摘要:

The Faipadajl Society is not responsible for opinioiis expressed before il b y Aufhors OY Spcakcrs. OF FOUNDED 1903. TO PROMOTE THE STUDY OF ELECTROCHEMISTRY, LLECTROMETALLURGY, CHEMICAL PHYSICS, METALLOGRAPHY, AND KINDRED 8UBdECTS. _ _ ~ _____ ~ - - _- - -______ ~ _ _ _ _ _ Vor,. IV. OCTOBER, 1908. PART 2. _ _ _ _ _ -- _ ~ _ _ _ _ _ _ _ _ _ _ _ ~ ______ ~ _ _ _ _ _ _ _ _ _ _ _ _ ~ - -~ .- T H E INDUSTRIAL USES OF OZONE, PARTICULARLY FOR THE PURIFICATION OF WATER. BY F. MOLLWO PERKIN, PH.D. ( A Pnpei read before the FaiTaday Society, Tuesday, May 12, 1908, Mr. LEON GASTER in the Chair.) The formation of ozone by the discharge of an electrical machine was originally noticed by Van Marum in 1785, but it was Schijnbein in 1840 who first actually prepared it and gave it the name “ozone,” from the Greek meaning “smell.” He also showed that it was much more active as an oxidising agent than ordinary oxygen.It is produced by the slow oxidation of phosphorus, and the peculiar smell of this element is really not the smell of phosphorus but the smell of ozone, and this can be shown to be the case by adding small quantities of substances to phosphorus which prevent its oxidation, when the smell is no longer perceptible. It also appears to be produced in small quantities by the burning of hydrocarbons. It is likewise formed in the open country, probably by slow evapora- tion or possibly by electronic action of the sun. Thus, where there are large quantities of water, as in the neighbourhood of the sea, the amount of ozone will probably be greater than in dry inland districts, although what is often at the seaside put down to the smell of ozone is simply the smell of decaying seaweed.It is formed in considerable quantities when fluorine acts upon water. If a drop of water is introduced into a tube filled with fluorine, reaction immediately ensues, and the tube becomes filled with deep blue vapour; this is ozone, which has a blue colour when concentrated- 3F, + 3H,O = 6HF + 0,. Ozone is also produced at the anode when acid solutions of water are electrolysed, particularly if the electrode is a platinum tube through which cold water is passed. Fischer and Massenez (2eit.f. anorg. Chem., 1907, 229) have obtained 25.27 per cent. of ozone in electrolytic oxygen by cooling to oo ; such a process would not however be satisfactory on a large scale.The best method to prepare it is to subject oxygen to the action of the silent electric VOL. IV. PART 2. T 682 THE INDUSTRIAL USES OF OZONE, PARTICULARLY discharge, the oxygen thereby receiving electrical energy and becoming converted into ozone, thus- 3 0 , + energy = 203. Consequently ozone is less stable than oxygen and is in a condition in which it will readily part with the energy originally received electrically in the form of heat--e.g., when the pure gas explodes or as chemical energy when it oxidises substances. The thermochemical equation accounts for its in- stability. 0, + 0 = 0, - 32,400 cal. Ozone is a blue gas-although when largely diluted with air this colour is not noticeable-which boils at -119"; it can therefore be obtained FIG.I. by passing ozonised oxygen through a tube surrounded by liquid oxygen (boiling point -1S2*5), a deep blue liquid being obtained. Its well-known sterilising properties are due to its great power of oxidation, and it is thus a very powerful bactericide. The employment of ozone or ozonised air for the purification of water on an industrial scale was suggested some years ago, but it is only within the last decade that the suggestion has been practically worked out and actually employed commercially.:: Of all the workers on the subject Messrs. Siemens and Halske have been most indefatigable and have fitted up works a t Paderborn and Wiesbaden, which have been in operation for some years and have given considerable satisfaction, particu- larly the former. The providing of a pure water supply to our towns, cities, and villages is of the very first importance.In some cases where the water comes from sources in which contamination of the supply is out of the question, such as from mountain lakes or from deep springs, no special purification is * Werner Siemens originally suggested its employment for this purpose in 1889, but the idea was put on one side, and not until 1898 was it again taken up by Messrs. Siemens and Halske.FIG. 2.FOR THE PURIFICATION OF WATER. 83 necessary. In other cases, however, where the source of water admits of or even invites contamination purification in some way or other is a sine quZ non. The method chiefly employed is mechanical filtration. Chemical methods, such as treatment with oxidising agents, can onlj7 be carried out on a small scale.Electrolytic methods, although frequently tried and continually patented, have also proved not to be satisfactory, at any rate on a large scale. The sand filtration method is partly bacterial and partly one of filtration. The surface of the sand becomes coated with a slimy deposit, which is partially of bacterial formation ; consequently the water first passes through the bacterial layer, which exerts a beneficial effect in destroying harmful bacteria, and also makes a much finer filter than can be produced by the more or less coarse-grained sand, and then it percolates through the sand. Sometimes, however, owing to flo-ods and special contamination, the filter- bed system breaks down, and then it may be a very serious matter for the populace.FIG. 3.-Battery of Ozonisers. Purification by means of ozone may be said to be electrical, chemical, and mechanical. The electric current is required to produce the ozone, thc ozone acts chemically upon the water, and the water is mechanically raised to high towers and allowed to trickle down over the layer of pebbles, where it meets the ozone : furthermore, it may be necessary or advisable to subject it to a previous filtration. Dr. G. Erlwein having kindly supplied me with details of the Siemens- Halske process as it is carried out at Paderborn and Wiesbaden, I will describe the first of these installations, as it is typical of the plant which they are supplying, and has now been worked successfully for some years.The ozoniser employed is shown in Fig. I . It consists of concentric pipes A and E placed one within the other. The inner one is of aluminium, and is connected with the leads carrying a high tension84 THE INDUSTRIAL USES OF OZONE, PARTICULARLY current, niarked in the diagram as +, as this is the positive pole. As currents of the high voltage employed are very dangerous, the leading-in wires are very thoroughly insulated and are passed through the hollow hermetically sealed pillars and the frame of the ozoniser. The glass cylinder E is the other pole; it is surrounded with water which can be circulated for cooling purposes, and as this is “alive” it receives its charge from it. The water which surrounds the glass cylinder receives its electricity from the iron-containing box, which is earthed, and consequently forms the negative pole.The annular space between D and E is where the silent discharge takes place. The complete apparatus consists of a cast-iron box divided into three chambers, the lower chamber for receiving and conveying the air to the ozone tubes, an hermetically sealed middle com- partment into which the ozone tubes are inserted by means of a stuffing-box gland, and an upper compartment for collecting the ozonised air. Fig. 2 shows the apparatus as it appears closed up. FIG. 4. A plate-glass inspection window is fitted to each apparatus, so that it is easy to see whether it is functioning properly owing to the appearance of the blue discharge. The ozone-room in which the ozonisers are kept is usually dark to enable the attendant upon entering it to see at a glance whether they are working properly-ie., whether the apparatus has a uniform bluish glow.An ozoniser of this construction carries an alternating current having a potential of 8,000 volts ; I h.p. per hour is required to operate it, and from 13.5 to 27 grm. of ozone is generated in that time, depending upon the amount of air which passes through the ozoniser and upon the degree to which it has been previously dried. The water at Paderborn and Wies- baden requires an average coilsumption of 1.3 grm. of ozone per cubic metre (35.3 cubic ft.). Consequently, taking the daily consumption of water at IOO litres per head of population, each ozoniser is capable of sterilising water in twenty-four hours sufficient for a town of from 2,400 to 4,800 inhabitants. The figure IOO litres per head is probably rather low for this country,FOR THE PURIFICATION OF WATER.85 therefore it is perhaps better to put the capacity of the ozonisers as sufficient for from 2,000 to 4,000 inhabitants. In the Paderborn works the installation consists of a battery of nine ozonisers, with two sterilisation towers erected outside the ozone chamber. The battery is made up of three independent sets, each consisting of three ozonisers arranged as shown in Fig. 3, which represents schematically the Paderborn plant. One of the three sets is kept in reserve while the other two are used to supply the sterilisation towers. The towers are 4 metres (141.2 ft.) high ; they are constructed of concrete and contain pebbles about the size of pigeon’s eggs.Over these pebbles the water trickles and is therefore broken up into a number of small streams so that a very large surface is exposed to the action of the ozonised air, which is forced under a gentle pressure up the towers by means of blowers. Each complete tower, as shown in Fig. 4, is divided into three parts-(I) the reservoir H for containing the water to be treated, ( 2 ) the sterilising compartment containing the pebbles, (3) the receptacle for collecting the treated water. The interior of each tower is divided by means of two partitions into four independent towers, all of which obtain their water from a common supply pipe with a valve C. Every single is divided by a grating into an upper and lower part pebbles 2 metres in thickness, and a 1ower.reservoir for STERlLlZATlOH TOWER tower or shaft containing the FIG.5. collecting the sterilised water. The water to be treated flows through the four-way supply pipe into each single tower ; here it passes through a sieve which causes it to fall in a fine shower on to the layer of pebbles through which it percolates, becoming ozonised, and finally collects in the reservoir. Each of the single towers is one square metre in cross-section, and about 15-20 cubic metres (529-706 cubic feet) of air passes through it in the twenty-four hours, At the sides of the tower cascades are built over which the escaping water flows to the final storage reservoir. All traces of dissolved ozone are thus lost by the contact with the atmosphere.The scrubber system is found to give better results than can be obtained by forcing ozonised air up through a large bulk of water, because, the water being in very thin layers ;is it percolates through the pebbles, a much larger surface is exposed to the action of the ozonised air than can be the case when the air is forced up in individual bubbles. In case of interruption either to the electric supply or to the blowers arrangements have been made by means of which the water is automatically shut off from the sterilising towers, thus preventing the inflow of unsterilised water into the town mains. For instance, if the current in one set of ozonisers be interrupted, thus stopping the ozone formation, a lever in connection with the electromagnet which is held in place by the passage of86 THE INDUSTRlAL USES OF OZONE, PARTICULARLY the current drops and closes an independent circuit, which in turn by electromagnetic action causes a floating conical rubber valve to drop and shut off the water supply to the four towers.On the other hand, should the blower break down, an aluminium disk which is inserted into the main air- pipe and kept raised by the pressure of the current of air as it passes under normal conditions drops, and likewise by electromagnetic action shuts off the water supply to the towers. In either case the fall of an indicator attached to the switch-board tells which set of apparatus is not working, a i d an alarm signal rings until the trouble is rectified ; consequently it is not possible for the pure water to become contaminated with the unsterilised water.The method just described is employed in cases where it is not required first to filter the water. Where the water contains suspended matter it is necessary to have a filtering plant in connection with the installation. The plant at Wiesbaden is arranged upon practically the same plan as that at Paderborn, and is constructed to treat 250 cubic metres (882.5 cubic ft.) of water per hour, which is obtained from springs situated near Schierstein, along a former arm of the Rhine. The plant is in duplicate, each part being capable of dealing with 125 cubic metres (451-25 cubic ft.) per hour, but as a rule only half the plant is in operation at one time, thus giving a reserve of roo per cent.Messrs. Siemens & Halske, besides fitting up large ozone plant, also build smaller laboratory and experimental apparatus to deal with small quantities of water, which can either be rised for purifying water on the experimental scale or might be used for oxidation of chemical products, and they are also suitable for use in dwellings or restaurants, &c. They have also shown their versatility by inventing and fitting up transportable apparatus which could either be used in war-time or for dealing with contaminated water supplies; and one has only to remember the terrible mortality from enteric fever which ensued in the Transvaal War to realise the importance of such a means of purifying water in camp and upon the battle-field, where ordinary filtering appliances would be useless and it is not always feasible to boil large quantities of water.The apparatus consists of two small wagons, each of which is hauled by one horse, The small dynamo and all the pumping appliances are worked by means of a petrol motor. This apparatus was employed in the recent Russo-Japanese War and gave the utmost satisfaction. Other cases where a portable steriliser might be of great use would be in cases of an epidemic where the water supply of towns or villages has become Contaminated. It is not so very long ago that a terrible outbreak of typhoid took place in Maidstone, and it will be remembered how great was the mortality. The source of the typhoid was ultimately traced back to the contamination of the water supply, and it was some considerable time before this became sufficiently pure to be again employed.One might not like the idea of drinking water containing dead typhoid germs, but it is certainly better than drinking water containing live germs, and in the case of ozonisation pathogenic bacteria are very susceptible to the action of the ozone. The compended table shows how complete the sterilisation of water is after ozonisation, and it will be noticed that where germs remain in the water they are of a harmless nature and non-pathogenic. The tables given only include a few cases, but both in France and in Germany, where so much work has been done with ozonisation. Similar results have been obtained in iiumerous cases in this country and abroad. Fig. 5 illustrates the Paderborn water sterilisation plant.FOR T H E PURIFICATION OF 1VATER.Before Ozonisation. 87 After Treatment. Source of Water. BACTERI 0 LOG1 C.4L RESULTS. Ozone Exferimeiztal Works, Martinkenfelde. Number of Bacteria per Cubic Centimetre of Water. Species of Bacteria Number after I Ozonisation. Ordinary. Pathogenic. i Source. 0 I 0 2 Cholera. Typhus. River Spree 9 , 9 9 7 7 >7 Spree water infected with cholera. Boiled water infected with typhus. Number before Ozonisation. 8 9 0 0 The operating costs are by no means high : at Paderborn only two men are required to look after the whole installation, so that the cost of labour is a comparatively small item. It is stated that a plant capable of treating two thousand cubic metres (70,640 cubic ft.) of water per hour requires 275 h.p., while 45+ h.p.is necessary for a plant capable of treating 200 cubic metres (7,064 cubic ft.) per hour. This works out at about wid. for the larger plant and about ad. for the smaller plant. These numbers refer to steam plant; if producer gas is employed the cost is slightly less. Of course the purity of the water to be treated also has a considerabie bearing upon the cost. The purer it is in the initial stage the less ozone is required to purify it, whereas if the water were very impure necessarily require to yield a product richer in ozone. THE OTTO SYSTEM. Another process which has been found to work very large scale for the purification of potable water is the the ozoniser would successfully upon a Otto system. The FIG. 6. ozoniser itself consists of a series of transverse plates so arranged that a dielectric plate is placed between each electrode plate, the arrangement being electrode, dielectric electrode, and is shown diagrammatically in Fig.6. VOL. IV--T588 THE INDUSTRIAL USES OF OZONE, PARTICULARLY The air is drawn or blown between the plates, the silent discharge passing between the spaces of the plates and thus ozonising the air or oxygen. There are an odd number of electrodes similar in arrangement to an accumulator, the odd and even being connected to separate poles of the source of current, the whole system being held in a frame. I 1 FIG. 7. Fig. 7 gives an idea of the manner in which the air passes over the plates. The alternating current machine of particular design is employed and the best results are said to be obtained with a pressure of 6,500 volts, the current intensity being 0*00146 ampere.Under these conditions the apparatus can FIG. 8. be used for hours without any appreciable warming taking place. The more rapidly the air is passed through the ozoniser, the better the yield of the ozone.88 THE INDUSTRIAL USES OF OZONE, PARTICULARLY The air is drawn or blown between the plates, the silent discharge passing between the spaces of the plates and thus ozonising the air or oxygen. There are an odd number of electrodes similar in arrangement to an accumulator, the odd and even being connected to separate poles of the source of current, the whole system being held in a frame. I 1 FIG. 7. Fig. 7 gives an idea of the manner in which the air passes over the plates.The alternating current machine of particular design is employed and the best results are said to be obtained with a pressure of 6,500 volts, the current intensity being 0*00146 ampere. Under these conditions the apparatus can FIG. 8. be used for hours without any appreciable warming taking place. The more rapidly the air is passed through the ozoniser, the better the yield of the ozone.FOR THE PURIFICATION OF WATER. 89 Another form in which revolving electrodes are enclosed in a metal chamber which forms one pole, employs a current with a tension of about 25,000 volts, and is stated to be very efficient when large volumes of air have to be dealt with. The Lahmeyer Electrical Company, Ltd., who are the agents i n this country for the Otto processj have also a very useful little apparatus for the sterilisation of domestic water supplies.The ozoniser works directly on to the water supply, and is automatically set in action by turning on the tap. The apparatus is worked from an ordinary 16-cap. lighting socket, and is designed for use upon IOO to 250 volt mains. If the current is alternatiiig it is transformed up to 3,500-8,000 volts. If it is direct then a small motor converter is supplied with the apparatus. Fig. 8 illustrates the manner in which the apparatus is connected with the water tap, and explains itself without further description. Fig. 9 shows the whole apparatus fitted up ready for use. Recently a slight modification has been made in the apparatus by the fixing of a better “emulsifier” for mixing the ozone with the water, which is much more efficient than the one shown in the illustration.The whole apparatus, together with the transformer, does not occupy more than 1-25 square feet of wall space. Such an ozoniser is capable of sterilising 250 quarts of water per hour, which of course is much more than would be needed for ordinary domestic requirements. At the moment of being drawn off the water has a distinct smell of ozone, but if it be poured from a jug into a tumbler the smell will be noticed to have completely vanished and no taste of ozone can be noticed on drinking the water. At the same time, it is probably advisable to allow the water to stand ten minutes or so in order that there shall be no doubt about the complete absence of ozorie. The ozone having done its work-that is, having sterilised the water-one does not desire to drink a disinfectant.As a matter of fact if the water is allowed to stand for ten minutes or is poured from the jug to the glass and back again and then again into the glass, no ozone remains, but the water contains slightly more free oxygen than ordinary water, and this is an advantage rather than a dis- advantage. Over five hundred of these ozonisers have been installed by the French Government in Paris. The Otto process, like the Siemens-Halske process, is also employed upon a very large scale for the sterilisation of water for towns and cities. At Nice an installation for treating 5,000,000 gallons per day has been in opera- tion for about three years.The circuit from which the power is taken is three-phase, and has a pressure of 10,000 volts at 25 cycles. The potential is reduced by means of a transformer to 220-110 volts. The motor for driving the circulating pump and alternator runs at 220 volts. The alternator generating at 220 volts and 500 cycles is transformed up to 20,000 volts, this high pressure being employed to excite the ozonisers. The process is also in operation in Paris, Dinard, Chantenay, Saint Servain, and other towns in France. The great advantage in employing ozone for tlie sterilisation of water supplies which are to be employed for drinking purposes is that no noxious material remains behind in the water. The ozone acts as an oxidising agent, gives up one atom of oxygen in the process, and there remains behind in the water simply oxygen ; that is to say, the water is more thoroughly aerated after the process of ozonisation than before.I should not be inclined to entirely dispense with filtration, but as the process is so extremely cheap, is so efficient, and so absolutely harmless, it certainly seems that the time has come for sanitary authorities to seriously90 THE INDUSTRIAL USES OF OZONE, PARTICULARLY consider the employment of ozone for sterilisation purposes to guard against the outbreak of epidemics. OTHER USES OF OZONE. Ozone is employed for sterilising the air of rooms and buildings. There are various forms of ozonisers employed for this purpose. In one case an ozone tube somewhat similar to the old Siemens tube is fitted on to a fan and rotated with it.The rotation causes air to be drawn through the tube and out again into the air. There is also an apparatus of the Otto type where ozonised air is blown into the room by means of a small electro-motor, which, as it revolves, works a blower and at the same time excites the ozoniser.::: Ozone is also used for maturing wines and in particular spirits. Spirit which would requirc years for ageing is matured in the space of a few minutes by emulsifying it with ozonised air. It has also been used for sterilising beer-barrels, which have, owing to secondary fermentation, an unpleasant smell, and are known in the trade as “stinkers.” It is also largely employed for bleaching flour and wheat. In this case, however, the apparatus is on a different principle.Ordinary air is passed through the filter and then supplied by a blower to the ozoniser, and thus becomes ozonised. The air is then passed through a spark-box, where a very small proportion of oxides of nitrogen would appear to be produced by the sparks passing in between the sparks in the box. In bleaching the flour the normal ainount of air passed through the ozoniser is practically roo cubic feet per minute. The resulting gas, which is air and ozone mixed with oxides of nitrogen, contains in every 40,000 parts by volume three parts of ozone and one part of oxides of nitrogen. The current is o-og ampere and the voltage employed about IO,OOQ. The ozonised air passing at this rate will sterilise and bleach as much as three tons of flour in one hour, which is an extraordinary effect when one considers the small amount of the bleaching agents employed. As showing that sterilisation as well as bleaching takes place, unbleached rye-meal contains 2,400 micro-organisms, and after bleaching 1,600 per grm. Unbleached wheat flour contains 540 organisms and after bleaching 170. Vanillin is another product which is manufactured by means of the oxidising action of ozone. Eugenol is first converted into izo-eugenol by means of caustic alkali ; the alkaline solution of iso-eugenol is then sprayed into a chamber, where it meets a current of ozone, and it is by this means oxidised into vanillin. When crystallised it is ready for the market. NoTE.-There has lately been a considerable correspondence in the daily Press in reference to the domestic use of ozone, for sterilisation of water and purification of the air in rooms, &c., it having been maintained that its use in this way is dangerous. Personally, I am not inclined to agree with this dictum. Breathed in large quantities, ozone produces a feeling of nausea, but that quickly goes off, and personally, although I have worked for weeks at a time in a small room the atmosphere of which was saturated with the gas, I have experienced no ill effects. When employed for sterilising water the excess of ozone almost immediately goes off. The personal equation may, however, have something to do with the effect of the gas when breathed in large quantities. consisting of aluminium gauze separated by a mica dielectric. * The Ozonair Company, by means of a fan, draw air through an ozoniser

ISSN:0014-7672    

DOI:10.1039/TF9080400081

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

FOR T H E PURIFICATION OF WATER. 91 DISCUSSION. Dr. G. Senter asked whether there was much difficulty in removing the last traces of ozone from the water. He remembered Nernst had once expressed the view that when ozone had stood for some time in contact with water it was difficult, if not impossible, to remove it completely by passing a current of air through the solution. In the portable ozone machines described by the author there did not appear to be any arrangement for the removal of the ozone. Dr. T. M. Lowry said he had been more impressed with the possibilities of the portable apparatus than with the large sterilisation plants. He thought that a cheaper and simpler way of dealing with town drinking water was to soften it and bring down the bacteria incidentally in the precipitated chalk.This had the advantage of improving the water for steam-raising purposes, and though the process was only in use in chalky districts where the water was so hard as to be a source of annoyance and danger, in domestic hot-water installations he believed it might be extended with very great advantage to waters of slight or moderate hardness. Dr. V. H, Veley stated that when engaged in attempting to prepare the purest nitric acid possible he had found that the best method for removing the last traces of nitric oxide was to allow the distilled acid to drop through an atmosphere charged with ozone generated in the usual manner. As to thc results of the bacteriological examination of water purified by ozone, it was perhaps fortunate for the human race that pathogenic bacteria were, as a rule, the most readily destroyed.Investigations had shown that there were both bacteria and lzyponzycefes (moulds), which were more persistent in their survival, but these were harmless. The speaker thought it was most useful to have on record a careful account of the sterilisation of water by ozone on a manufacturing scale, more especially as in certain processes now before the public they were induced to believe that merely passing an electric current of 30-40 amperes through water brought about ozone sterilisation. The Chairman: Dr. Perkin has given a very interesting account of the ozonising process, in particular in relation to the purification of polluted water for drinking purposes. I should like to bring before your notice the result of an experiment which I witnessed during a visit last year to Phila- delphia.I saw a complete ozone plant for the purification of water, the process being worked by the United Water Improvement Co., at Philadelphia. The plant was erected to treat the foul water obtained from the river Schuylkill, in West Philadelphia, which is described as being nothing but diluted sewage and is estimated to contain as much as 2,500,000 bacteria per square centimetre according to the testings made by the official bacteriolo- gists of the cities of Philadelphia and New York. After a rough straining to remove the coarser particles of suspended matter the water was treated by the ozonising process, and after treatment the bacteria were reduced to an average of about 2 5 , mainly of hay bacillus, which is supposed to have no effect on human organism.The Bacillirs coli, indicating the organic pollution of water, was claimed to have been completely killed by the ozonising pro- cess. The offensive odour was also destroyed and the discoloration of the water was to a great extent removed. The important part of the process of water purification is that it is entirely mechanical and automatic. A pressure of 10,000 volts and 103 cycles was used, and by the operation of re-actant coils and condensers voltaic arcs and sparks are prevented, the current passing as a pencil of blue light from each of some millions of metallic dis- charge points across a short air-gap to nickel receivers. Atmospheric air is9 2 THE INDUSTRIAL USES OF OZONE, PARTICULARLY drawn across this gap by means of an air-pump, and in so doing is partially converted into ozone.The ozonised air is then forced into a stand-pipe, in which it meets a current of water flowing in the opposite direction. It is claimed that the cost of erection of ozonising plant is not greater than that of the usual method of sand filtration ; and it has the undoubted advantage that it only takes a few months to build a large ozonisiiig plant, whereas sand filtra- tion often takes many years to complete. The space occupied is also very small. The plant which I saw in Philadelphia, estimated to be capable of treating for about 30,000 inhabitants, took only 30 by jo feet of ground against many acres of land which would hare been required for sand filters.The ozonising process has received attention from a very large number of manufacturers, and several processes apart from that so fully described by the author and illustrated with lantern slides are now in use, amongst which may be mentioned also the processes adopted by Messrs. Lahmeyer Co., the Ozonair Syndicate, &c. The size of plant now in use varies, some being capable of treating as much as 5,000,ooo gallons per day, like the one erected at Nice. According to the claini made by the inventors the cost of energy for sterilising parposes is very small indeed. It would be interesting to know whether any experinients were carried out in London, and if so, with what results. An important point in favour of the use of ozone for sterilising pur- poses was the fact mentioned that small complete plants are now available which can easily be transported from place to place, being very useful during military manceuvres or in time of war, &c.The ozone plants can also easily be increased in capacity with the requirements by simply increasing the number of batteries of ozonisers as shown by the author. It is interesting to notice that this ozonising method is being employed in very small towns, and its future development ought to be carefully watched by all those who take an interest in the purification of water and wish to have it as wholesome as possible for drinking purposes. A simple and compact sterilisation equipment was recently shown by the Lahriieyer Co., at the Municipal Building and Public Health Exhibition held at the Agricultural Hall from May 1st to 12th, and I understand that at the Franco-British Exhibitioii the Ozonair Syndicate are showing a complete plant in actual operation, indicating the many uses to which ozone could be put.The many recommendations which have been and are constantly being made to boil water before drinking are not as a rule carried out ; and although household filters have also been largely recommended, yet these require a great deal of attention and frequent cleansing if they are to answer their purpose satisfac- torily. The ozone treatment, it is claimed, kills the dangerous bacteria, and therefore makes the water quite wholesome for drinking purposes. The work of the electrochemist, in improving these processes, is a very useful one, and a great deal may be expected from the extensive use of suitable ozonising apparatus.Dr. H. Borns would have been glad if Dr. Perkin could have given some information on the French high-tension ozone plants. We had not of late heard anything about the plants of Abraham and Marrier : were they still in existence ? It was interesting to learn that the flour process was worked on a large scale by Leetham and Cramp ; Alsop, Andrews, and many others had, of course, tried to treat flour with ozone. The figures as to bacteriological tests which Dr. Perkin had quoted went back to 1901 and 1902. A lively coiitroversy had subsequently arisen as to the efficacy of the ozone treatment of potable water, but, so far as the speaker remembered, the result had been favourabie to ozone.Paderborn was a town of about ~5,000 inhabitants, in Time alone will prove their practical value.FOR T H E PURIFICATION O F WATER. 93 which Charlemagne had held a Diet in 777. Wiesbaden had itself more than IOO,OOO inhabitants, he believed, and sheltered at least as many visitors every year. The thermal springs of both these places had been known to the Romans, but the actual Wiesbaden was very modern, also in its claims as to water supply. Mr. W. Pollard Digby (coininunicafcd) thought that Dr. Perkin’s paper, setting aside the preamble about filtration and its pleas for sterilisation, resolves itself into telling a little more than can be gleaned in Science 4bslracfs upon this subject save for the affirmation “that purification by means of ozone may be said to be electrical, chemical, and mechanical.” But the sentence is hardly worthy of a scientist of Dr.Perkin’s high standing unless he was jesting. To affirm that purification by ozone is electrical or mechanical has nothing to do with the actual problem of purification. One might as well affirm that in some cases the purification was gaseous and leathery because in certain cases belt-driven centrifugal pumps driven by gas-engines are used in pumping the sewage. Upon the subject of the purification of impure waters, purification being understood as meaning sterilisation, he had perhaps as close an experience with the problems of water sterilisation as any member of this Society, having worked at this problem under the late Professor Kanthack and under Dr.Rideal in 1897-98 ; the medium then being used was an electrolytic hypo- chlorite of soda. These and other experiments were reviewed in a Paper by Mr. H. C. H. Shenton and himself read before the Society of Engineers in 1906, It would perhaps not be improper in discussing a paper on Ozone to put forward a few figures relating to a product also electrochemical, viz., sodium hypochlorite, which was equally efficacious and far cheaper than ozone. Dr. Perkin tells us that 13-5 to 27 grammes of ozone are produced per 1i.p. hour. Taking the higher figure, we thus have a yield of, say, 36 grammes per kw. hour. Now “the water at Paderborn and Wiesbaden requires an average consumption of 1.3 grammes of ozone per cubic metre” (say 230 gallons), so that for a consumption of I kw.hour 28 cubic metres of water (of whose composition bacteriologically and chemically nothing is known) can be sterilised. One would probably be wrong in assuming that it was a very bad water, high in organic impurity, akin to the effluent from a sewage settling tank. Now, it has been established beyond question that I grm. of available chlorine in the form of the hypochlorite will sterilise 1-21 cubic metres of settling tank-sewage effluent or 1.5 cubic metres of filtered sewage effluent. In any good electrolyser I kw. hour will produce from 150 to 200 grms. of available chlorine. To avoid any imputation of special pleading he would take the lower figure. This, then, gives a sterilisation of 181.5 cubic metres of unfiltered efflluent from a settling tank as against a maximum of 28 cubic metres of drinking water of unknown but presumably not greater organic impurity from consumption of I kw.hour of electrical energy. What, then, is to be said of ozone against sodium hypochlorite ? Obviously the cost of salt in the latter case. Ignoring the respective capital outlays required, and taking the running costs only, calculating the cost of electrical energy in each case at Id. per kw. hour and of sodium chloride for the hypo- chlorite solution at Id. per 10 Ibs. The cost of sterilising Paderborn and Wiesbaden water then becomes 3’57d. per 100 cubic metres. In 1896-98 his notebooks showed that sodium hypochlorite was being pro- duced at an inclusive charge iipon the basis stated of Igd. per kilogramnie of94 THE INDUSTRIAL USES OF OZONE.available chlorine. The cost of sterilising unfiltered sewage-tank effluent was thus 1’24d. per cubic metre. Dr. F. M. Perkin, in reply to Dr. Senter, said there was no great difficulty in removing the last traces of ozone froin the water by simple aeration, and it was possible that the last portion might be removed by coming in contact with organic matter of bacterial nature. Dr. Senter remarked that Nernst considered that when ozone had stood for some time in contact with water it was difficult to remove it. In the case in question the ozone was not in contact with the water any length of time, only sufficiently long to destroy bacterial matter. Dr. Lowry referred to the softening method by precipitating the chalk, which incidentally removes a large amount of the bacteria, but it was doubtful whether bacterial removing action was as efficient as when ozone was employed.He was very much interested in Dr. Veley’s remarks, in which he stated that he was able to remove the last traces of nitric oxides by allowing the acid to drop through an atmosphere charged with ozone. He quite agreed with him that the passage of an electric current through water had very little sterilising effect. Mr. Gaster’s experience in America was of interest, and he understood that the Americans are now considering the matter of ozone sterilisation to a very considerable extent, and he was quite in agreement with him that it was very difficult to get householders to filter or boil their water in case of epidemics, and therefore the ozone treatment was much more preferable, especially if the apparatus was fitted to the water supply so as to work automatically.In reply to Dr. Borns, he was not aware whether the Abraham and Marrier plant was still in existence. The historical facts in reference to Paderborn were very interesting. In reply to Mr. W. Pollard Digby, he would point out that the ozone processes to which reference had been made were used for the sterilisation of potable water, and he had in no case referred to the sterilisation of sewage effluents. Mr. Digby appears to be wedded to the use of sodium hypochlorite rather than to the use of any othcr form of sterilisation. Now, sterilisation by means of hypochlorites was an electrochemical process, and sterilisation by means of ozone was also an electrochemical process.For one class of work hypochlorites might be the better and for another class of work ozone ; and certainly as far as the sterilisation of potable water was concerned he thought that ozone was very much superior to the use of hypochlorites. When ozone was employed the resulting product was simply oxygen, the extra atom of the oxygen in the ozone being used for oxidising and sterilising purposes. By using hypochlorites sodium chloride was introduced into the water. The quantity, indeed, was small, but at the same time he held that water for potable purposes should have no substance added to it other than oxygen, which is practically the same as giving it a slight excess of aeration. He had often spoken in favour of the einplcyment of hypochlorite for purposes of disinfection, particularly in the case of the very successful Poplar plant, and for treatment of sewage it undoubtedly had shown very good results. Ozone has not so far been employed to any great extent for the sterilisa- tion of sewage effluent, but provided this were filtered there scems no obvious reason why it should not be used. It would simply be a question of whether hypochlorite or ozone were the cheaper material to use. He was quite willing to admit that Mr. Digby had a large and varied experience in connection with the sterilisation of waters, but his remarks showed that he had had very little experience in sterilisation by means of ozone.

ISSN:0014-7672    

DOI:10.1039/TF9080400091

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

DETERMINATION OF BOILING POINTS OF VERY SMALL QUANTITIES OF LIQUIDS. BY L. O'DOWD AND F. MOLLWO PERKIN. ( A Paper rend before the Favaday Society, Tuesday, May 12, 1908, Mr. LEON GASTER i n the Chair.) The determination of boiling points of very small quantities of liquids by distillation is by no means satisfactory, because in the first place considerable loss in the already small quantity of liquid may take place, and it is difficult to actually arrive at the boiling point owing to the time necessary to heat the thermometer up so that it may show the correct temperature, and the liquid often all distils over before this happens. Various methods have at one time or another been suggested for determining boiling points for very small quantities of liquids, but few of these have been accurate and reliable.Of course it is no use trying to ascertain the boiling point of very small quantities of liquid which is not pure, but it often happens in chemical research that one obtains very small quantities of pure products, and for purposes of identification or even simply to ascertain the boiling point of an unknown substance some reliable method is necessary. In some textbooks a method is described which, if it gave reliable results, would be very satisfactory. A small glass tube about 6 cm. long and about $ cm. in diameter, closed at one end, is fastened by means of a piece of platinum wire against a thermometer, and the thermometer and tube are fixed by means of a clamp into a beaker containing sulphuric acid or other liquid of high boiling point.The beaker is fitted with a stirrer in the ordinary way. The determination of the boiling point is made by placing I cm. of the liquid into this little test-tube ; then a capillary tube, which is sealed together about I C.C. from its end, is also placed into it so that the liquid reaches about up to the sealed part of the capillary. The directions for taking the boiling points are as follows :- The liquid in the beaker is heated by means of a burner, and in order to insure the steady rise of temperature it is agitated by means of the stirrer. When the liquid in the test-tube has nearly reached its boiling point bubbles of air commence to rise up through the liquid from the end of the capillary. The burner is now removed from below the beaker and the liquid thoroughly agitated so that the temperature may be uniform.It is then again replaced for a short time and again removed, these operations being repeated so that the rise of the temperature may be easily noted from degree to degree. As the boiling point is neared bubbles of air rise more rapidly, until when the liquid is just boiling they are given off in a continuous chain. At this point the thermometer is read, and by repeating the operation two or three times, each time putting a fresh capillary in, it is said to be possible to obtain close results. We very carefully tried this method but found it to be anything but accurate. With moderately low boiling substances the temperature might be ascer- tained within two or three degrees. With very low boiling substances it is 9596 DETERMINATION OF BOILING POINTS OF quite inaccurate, and with high boiling substances it was also not to be depended upon.We then tried various methods of modifying this process in order to see whether it might be possible to make it accurate. For example, a piece of platinum wire was fused through the end to the small test-tube, and an improvement was undoubtedly obtained, but even yet the results were by ;lo following process, which gives apparatus is depicted in the means accurate. Finally, we devised the results leaving very little to be desired. The diagram. A flask A which holds about f 3 100-110 C.C. of fluid is placed upon a wire gauze fastened over an inverted cone, such as is used to prevent Bunsen burners from flickering.The object of using this kind of chimney is that the heat may be evenly distributed upon the bottom of the flask. The flask has a very wide neck, about 4 cm. in diameter, which is fitted with a cork having three holes bored in it. Through the central hole a thermometer is passed, and through B a small thin-walled test-tube, about 7-8 cm. long, and having a diameter of 9 cm. This tube, however, is not passed directly through the cork but passed through a piece of glass tubing which is fitted into a cork so that it may be inserted and with- drawn without any difficulty. And, furthermore, if it happens to be moist with sulphuric acid, should this be the heated liquid employed, the cork will not be charred. In order to prevent the tube from slipping through into the flask the top of it is slightly widened out, so as to act as a collar.The thermometer also passes through a similar tube, and to prevent it dropping down too low a piece of rubber tubing C is placed round it to act as a support. The stirrer D of glass rod fits loosely through another tube, so that the air, as it expands upon heating, shall not set up a pressure.VERY SMALL QUANTITIES OF LIQUID. 97 About 4 C.C. of liquid, the boiling point of which is to be determined, is placed into the tube, and then a capillary tube, sealed at one end, and about 1-14 cm. long, is dropped into the liquid in such a way that the open end is to the bottom. The determination is then carried out as follows :- The temperature is raised by means of a Bunsen burner, the liquid being gently stirred in the meanwhile.The temperature is raised fairly quickly at first until a continuous stream of bubbles is given off from the bottom of the capillary tube. The source of heat is then removed and the temperature allowed to drop, the heating liquid being thoroughly stirred while it cools. As the temperature drops the bubbles begin to be given off less rapidly, and finally stop altogether. At the moment the bubbles cease to be given off- that is, when the pressure of the vapour within the tube is equal to the atmospheric pressure-the thermometer is read off and this is the boiling point of the liquid. A second determination can be made by at once again rapidly rising the temperature before the liquid is sucked back into the capillary tube. The stream of bubbles is again obtained, and on cooling down a second reading may be taken as before.It is found that by proceeding in this manner, and being careful to stir, absolutely accurate results may be obtained. If the liquid is not stirred the results are by no means accurate. This is, we think, due to the condensed vapour which has risen up in the tube B, which, being cooler than the heating bath, runs down to the liquid and stops it boiling. This, however, does not affect the thermometer sufficiently rapidly to drop the mercury, consequently the liquid ceases boiling inside the tube B and too high a boiling point is registered by the thermometer. We append a table of boiling points obtained by this apparatus. Column I gives the actual boiling point, those marked in asterisk having been obtained by previous distillation with the same thermometer, the others being the known boiling points of the substances taken from the literature.Column 2 gives the boiling point obtained with this apparatus when stirrer was used. Column 3 gives the results when no stirrer was employed. hfean Experimental Boiling Point. - Actual Boiling Point. 1 With Stirrer. 1 Without. Ether . . . . . . . . . Acetone . . . . . . . . . Hexane . . . . . . . . . Distilled Water . . . . . . Anisole . . . . . . . . . Aniline . . . . . . . . . Nitrobenzene . . . . . . Safrol . . . . . . . . . Ethyl propionate . . . . . . :::Q8.00 35.75' 56.8' 67.0' - 98.2' 206.0' 231.2' - - - I 0O'O0 99'5' 154'5' I 84.0' 209.0~ 234.0~ It is obvious that, with efficient stirring during cooling, the closeness with which the temperature of the inner liquid keeps to that of the outer depends on the rate of cooling, and this in turn depends upon the volume of the outer liquid.If, therefore, great accuracy is required, it is only necessary to employ a standard thermometer, a large flask to contain the heating liquid, and, perhaps, a mechanical stirrer. Now, as the rate of cooling at any time depends upon the difference of temperature between the liquid and the air98 DETERMINATION OF BOILING POINTS. the same amount of accuracy can be obtained for low temperatures by using a much smaller flask than would be necessary for high temperatures, because the cooling is slower when the temperature approaches that of the atmos- phere. It is also an all-important feature that the small test-tube should dip well into the heating liquid to ensure thorough heating of the condensed liquid within the tube, because this runs back down the sides and would otherwise stop the boiling. And, finally, the thermometer should be read when the inner liquid ceases to give off vapour-that is, when the last bubble stops increasing in size. Under these circumstances, all errors due to thickness of glass, &c., may be neglected. After being in use for some little time the sulphuric acid becomes dark in colour. This can b’e prevented and the acid again be rendered colourless by the addition of a few sinall crystals of potassium nitrate, which are easily dropped in by removing the small tube.

ISSN:0014-7672    

DOI:10.1039/TF9080400095

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

DETERMINATION OF BOILING POINTS. DISCUSSION. Dr. Senter asked if it was quite certain that the outside liquid had the same temperature as that in the small tube containing the capillary when the reading was made. Dr. Perkin, in reply, said that the boiling point of the liquid in the small tube was obviously the same as the temperature of the outer liquid, because in the table given the boiling points marked with an asterisk were first obtained by distillation, using the same thermometer, and it will be noticed that the results obtained by the other method are almost identical.

ISSN:0014-7672    

DOI:10.1039/TF9080400098

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

ON T H E UTILISATION OF THE ATMOSPHERIC NITROGEN IN THE PRODUCTION OF CALCIUM CYANAMIDE, AND ITS USE IN AGRICULTURE AND CHEMISTRY. BY DR. ALBERT R. FRANK. ( A Paper ?,cad hefove the Farnti1i.y Society 01% Tuesday, ?fine 9, 1908, Dr. F. MOLLWO PEKKIN Ln the Chair.) When Liebig, about the middle of last century, laid down the scientific basis of the natural laws of agriculture and the cultivation of plants, he showed that the essential condition for ensuring the soil against loss of plant- food, and thereby enabling it to maintain its fertility, was the supply of such mirzeral foods as the plants require for their growth. These mineral foods are continually being withdrawn from the soil, where they are by no means over- abundant in available form, by the crops. Among such foods Liebig placed phosphates and salts of potassium in the front rank, and thus founded his theory of mineral manure.As regards bodies like oxygen, hydrogen, carbon, and nitrogen, which are used for building up the intrinsic organic plant substances, Liebig maintained, in opposition to the supporters of the vegetable theory, which was believed in up till then, that the requirements of vegetation were continually and adequately supplied by the atmosphere, and that the effect of the nitrogen contained in certain bodies widely known in practice as efficacious manures, such as bone ash and guano, was of less importance than that of the other inorganic plant foods. Technical chemists adopted Liebig’s suggestion with enthusiasm and success. After the discovery of the rich mineral phosphate deposits, the conversion of these into the higher phos- phates by treatment with sulphuric acid was utilised with much success.The author’s father, Professor A. Frank, of Charlottenburg, succeeded, after the Stassfurt deposits were discovered, in placing at the disposal of agriculturists, the world over, an inexhaustible supply of the much needed potassium salts. As a result of the successes achieved in agriculture by Liebig’s minera2 theory, observant investigators, and amongst the first of these Liebig himself, could not in the long run ignore the fact that, by the addition of bodies con- taining nitrogen to the mineral manures, an essential requirement of plant life was met, and, at the same time, an improvement in the financial con- dition of the manure trade must ensue.In consequence an immediate demand for manures containing nitrogen, most of them of organic origin- e.g., bones, blood, offal, and fish guano-arose. These, however, only partially supplied requirements, while at the same time the Peruvian deposits of animal guanos were being very rapidly depleted by an ever increasing demand, I t became necessary, therefore, to turn to those inorganic compounds of nitrogen which had definitely been proved by scientific research to be suitable for plant food. Of these the two most important were the salts of ammonia, especially ammonium sulphate, the manufacture of which on a large scale from the gas liquors was first carried out in England in the early sixties, and the nitrates, of which an extensive deposit, in the form of sodium nitrate, was discovered on the rainless plateaus of Peru and Chili as early as 1830.Their application to agriculture, however, dates from 1860. Since ammonium salts 99IOO T H E UTILISATION OF ATMOSPHERIC NITROGEN have up till now only been profitably obtained as a by-product in the manu- facture of coal, gas, and coke, their production, in spite of the great increase from 10,000 tons in 1860 to about 600,000 tons last year (of which England uses up some 316,000 tons), is limited and dependent on other factors than agricultural demand. OUTPUT OF AMMONIUM SULPHATE IN ENGLAND. Year. I 898 1900 1901 1902 I903 I904 '905 1906 '907 I899 Total Production. Tons. 196,500 208,000 210,000 228,500 229,000 234,000 245,000 268,500 289,000 3 16,000 Average Price Per Ton.& s. d. 9 2 78 11 5 9Q I 0 I 1 4 11 16 3 12 9 3 12 3 8 12 I 0 9 I2 0 9 11 I5 3 I1 2 0 Total Home Consumption. Tons. 65,000 58,500 65,000 68,297 68,700 70,200 71,200 75,400 78,000 87,500 Used in Agriculture. This may be anything between 90 to 75 per cent. of the total home consumption, the balance being absorbed in arts and manufacture. OUTPUT O F AMMONIUM SULPHATE I N GERMANY. Year. I899 I 900 1901 I 902 I903 I904 I905 I 906 Total. Tons. 84,000 98,000 100,000 106,500 133,000 140,000 146,000 I 82,000 203,000 235,000 From Coke. Tons. 70,000 84,000 84,500 88,500 I 13,000 I 17,000 120,000 I 52,000 168,000 197,000 __ From Gas Works. Tons. 14,000 14,000 15,500 I 8,000 20,000 23,000 26,000 30,000 35,000 38,000 I t was these circumstances which placed sodium nitrate in the front rank of nitrogenous manures, and which caused the world's demand for these substances to rise from 935 tons in 1830 to about 1,740,000 in 1907 (see Fig.I). Of this amount Europe absorbs 1,400,000 tons and the U.S.A. about 340,000 tons. 20-25 per cent. of this being employed in the manufacture of chemicals and explosives, while the rest is used for agricultural purposes. Germany, which on account of the uncertain climate of its northern provinces, and because of its extensive beet sugar industries specially needs manures, is the largest consumer, importing over 500,000 tons yearly, about 400,000 of which are utilised in agriculturc. The guano deposits which at first were considered inexhaustible have now practically come to an end, and the same remark applies to the strictly limited nitrate deposits in the rainless region of Western South America.Agriculturists and political economists naturally regard with considerable anxiety the approaching disappearance of the deposits, while the demand for nitrates is steadily increasing year by year. Whether the date of exhaustion will be twenty or forty years hence is, on account of the vastIN T H E PRODUCTION OF CALCIUM CYANAMIDE IOI importance of the question, of little consequence, seeing that even during the last few years the price of sodium nitrate has risen 35 to 40 per cent. (in Germany), an increase due less to speculators than to higher working expenses and growing difficulty of production. It is also manifest that the chemical industries can afford to pay for the nitrate-which they consume in the pro- duction of nitrogenous compounds, nitric acid, and explosives-higher prices than the agriculturist is able to give.The price of sodium nitrate reveals, in addition, the state of the market for other nitrogenous manures. Ammonia and ammonium salts have likewise shown a marked advance, and agricul- turists who have urgent need of these manures, not only for producing their present average crops, but also for securing the increased output made neces- sary by the growth of population, an urgent necessity pointed out some years ago by Sir William Crookes, were threatened with a serious nitrogen famine. t8io dd30 4950 /d?o d@O A9P FIG. I.-SALTPETRE PRODUCTION IN CHILI. It is well known to all that the atmosphere surrounding our earth contains a diffused and practically inexhaustible supply of nitrogen, totalling about 4,041,200,000,000,000 tons.This works out at 31,000 tons of nitrogen over each acre of the surface of the globe, or the still air over every nine acres contains about 280,000 tons-ie., the same amount which is contained in the 1,740,000 tons of Chile saltpetre exported from that country in 1907. We know, further, that uncultivated plants, partly through certain organs which exist in them, as well as in leguminous plants, and partly by the aid of bacteria inhabiting the soil, are able to absorb the nitrogen they require from the air diffused through the soil. Furthermore in 1775 Priestley showed that atmospheric nitrogen under the influence of the electric spark combined with atmospheric oxygen to form nitric acid, the latter being conveyed by moisture to the soil and then to the plants.But all this accumulated experi- mental knowledge, important though its results undoubtedly were, did not afford any clue to the possibility of producing nitrogen compounds in con- siderable masses, nor was it freely at the disposal of agriculturist or chemist. The method devised by Fownes and Young last century, and experimentally applied by Bunsen and Playfair, showed that by passing atmospheric nitrogen over carbon and the alkalies or alkaline earths, the carbon compound102 T H E UTILISATION OF ATMOSPHERIC NITROGEN cyanogen could be formed from which by further treatment ammonia could be obtained.This method, in spite of its extensive application and the many improvements which Marguerite and Sourdeval and later Ludwig Mond introduced in its technical details, produced no practical result, on account of the difficulty of attaining the requisite temperature. It was further com- plicated by the fact that the construction and maintenance of the apparatus, owing to the materials used in the furnaces, gave rise to what were then insuperable difficulties. The first successful advance was made through the discovery and application of the dynamo, which rendered it possible for electricity to be supplied in considerable quantities. By this means a hitherto unattainable temperature could be produced in quite a restricted space. Up to this time, now some few years ago, the necessary energy had to be obtained, except in so far as it was produced by reaction from the molecular energy of the elements, by means of the chemical process of combustion.” With the application of the dynamo and the invention of the electric furnace by Siemens, this process was greatly modified, as by means of electric energy thus applied heat could be produced by means of the electric arc or of an electrical resistance, and could be brought to bear directly on to the chemically reacting mix t ure.With these improved means at their disposal, investigators endeavoured once more to find a solution, as already stated, of the all-important question of the fixation of nitrogen. Subsequent to 1894, when Thomas L. Willson and Moissan carried on the manufacture of carbide on a large scale in the electric furnace, the author’s father, Prof.A. Frank, in a Paper’ published in February, 1895, opposed Moissan’s views as regards the possible use of this carbide combined with atmospheric nitrogen, for the preparation of cyanides and amides. Tests carried out in conjunction with Dr. N. Car0 on this point established the truth of his hypotheses and further led to the invention of a method for the preparation of cyanides, cyanamides, ammonia, and other nitrogen com- pounds. It is on the technical and industrial manufacture of these and their value that the author has this evening to speak to you. The other way of fixing nitrogen, on which much successful work has been accomplished, by oxidising it and turning it into nitric and nitrous acid by means of the electric spark, was soon established on practical lines, firstly with unsatisfactory technical results at Niagara Falls by Bradely & Lovejoy, and then by the magnificent discovery of Birkeland & Eyde, as well as by the improvements which are now being perfected due to Schonherr and the Badische Anilin and Soda Fabrik.Prof. Birkeland made some highly interesting remarks on the oxidation of atmospheric nitrogen in this room in July, 1906, which you will all remember. In amplification of these the author may add that the production of calcium nitrate by the Birkeland-Eyde process seems to be developing exceedingly well in Norway, and that the factory mentioned by Prof. Birkeland is actually established at Notodden and is producing this substance.It should, however, be noticed that this industry has not made much progress in any other land save Norway, but it should not be forgotten that it is only in this Northern clime that electrical energy can be as cheaply obtained on account of its unrivalled resources of water power. It would therefore seem probable that Norwegian saltpetre is destined to remain the only direct competitor of the Chilian variety. As will be seen later on in my Paper, the two methods of nitrogen fixation I Vcrharzdlungen des Vereiizs ZILY Bc/ordeung des Gewerbflcisses, 1895, No. 2, February : (‘ ffber Gewinnung von Acetylen und dessen Verwendung zur Herstellung von Alkohol,” &c. By Dr. Adolph Frank Charlottenburg.IN THE PRODUCTION OF CALCIUM CYANAMIDE 103 differ greatly as regards their chemistry.Physically they are similar ; for, properly speaking, they are not electrical, but should be considered purely thermal processes. They do, however, differ in that the fixation of nitrogen by carbide is an exothermic process, in which heat is given out, while the combination of oxygen and nitrogen is endothermic--i.e., it absorbs a large amount of heat, and for the fixation of an equal quantity of nitrogen requires at least three times the energy that the former process calls for. The researches instituted, as mentioned above, by Frank & Car0 in 1895 were first carried out on calcium carbide mixed with sodium carbonate. But as the yield of cyanide obtained in this way proved unsatisfactory, they soon substituted carbide of barium therefor, a substance which at that time could be more easily obtained, and this they found absorbed nitrogen isolated from the air with great avidity at a temperature of between 700° and 800° C.Frank and Car0 were then contemplating the transformation of barium cyanide by treatment with carbonate of sodium or potassium into cyanide of potassium, which at that time commanded a very high price, with a considerably increasing demand. The first experimental plant was con- structed with the object of perfecting as far as possible the process for obtaining cyanide of potassium and yellow prussiate. They soon found that the nitrogen absorbed by barium carbide was not merely in the form of cyanide (Ba (CN),), but that it was also present in the form of a more complex compound. The latter was found, on examination, to be cyanamide of barium BaCN,, from which they inferred that the reaction had taken place according to the following equation- BaC, + 2N = BaCN, + C.Thus it appeared that in the reaction of carbide on nitrogen half of the carbon contained in the carbide had been set free. The proportion of cyanide and cyanamide of barium in the reacting mass was on an average as two to three, the product containing 30 per cent. of barium cyanide and 45 per cent. of barium cyanamide, the remainder consisting of barium oxide and car bo n . The transformation of the barium cyanamide into barium cyanide could be easily brought about by melting the mass containing both cyanamide and cyanide, with a flux such as potash or soda according to the following equa- tion- Ba (CN) , + BaCN, + C + 2K, CO, = 4KCN 3- 2BaC0,.The great progress which had meanwhile been made in manufacturing carbide of calcium on an industrial scale gave rise to a renewed attempt to try again the method of treating carbide of calcium with nitrogen, which had been previously abandoned owing to the difficulties which it offered at first starting. It was then discovered that the small yield of cyanide obtained in using carbide of calcium without an additional flux could be further reduced, and that no cyanide need be formed at all, but that the reaction wbuld proceed in accordance with the following equation- CaC, + 2N = CaCN, + C, and result in the formation of cyanamide of calcium alone, whilst, as has been seen, in using carbide of barium the corresponding cyanide was also formed.About this time the patentees, Messrs. Frank and Caro, together with the well-known electrical firm Siemens and Halske, and the Deutsche104 T H E UTILISATION OF ATMOSPHERIC NITROGEN Bank of Berlin, founded the Cyanid Gesellschaft of Berlin, for the further development of the process. The primary object of the new Company in taking up these inventions was to turn cyanamide of calcium into cyanide of potassium, for which there was an extensive and increasing demand for the purposes of gold extraction in South Africa and the United States. It is common knowledge that this object was successfully accomplished, The low atomic weight of calcium carbide compared with barium carbide, owing to which 64 parts in weight of calcium carbide sufficed to bind about 28 parts of nitrogen, seemed to point to the conclusion that by using calcium carbide it might prove feasible to produce those nitrogenous compounds also in which the nitrogen would only command a low price, such as fertilisers, &c.Further research in this direction was starting with calcium cyanamide as the raw material for producing ammonia, especially when it turned out that the total nitrogen contents of the calcium cyanamide could by treatment with hot water be turned into ammonia without any difficulty or loss. The process is effected according to the following equation- CaCN, + 3H,O = CaCO, + 2(NH,). In spite of the fact that this reaction requires an excess of water and a high temperature, and that acknowledged authorities on agricultural subjects passed unfavourable opinions in view of the presence of the poisonous cyanide group in the product, in consequence of a proposal made by me, an attempt was made to utilise crude calcium cyanamide directly as a fertiliser, burying it in the ground like any other manure.These experiments were first carried out in pots only. The results were satisfactory enough to indicate that the doubts entertained as to the applicability of the product as a fertiliser were groundless. Thereupon field experiments were arranged on an adequate scale at a large number of agricultural experimental stations, in most countries posscssing agricultural interests, and in connection with almost every class of agricultural produce, and these have been continued for the last six years without intermission.’ As has been the case with many other artificial ~nanures, a great outcry was, and still is, made warning farmers against the use of calcium cyanamide, popularly known as nitrolim, or at least advising that it should be employed with the utmost caution.*This outcry originated in the fact that not only farmers but even agriculturists are saturated with intense conservatism, and that initial failures did here and there occur when first using calcium cyana- mide.It is, however, certain that manufacturers must in the first instance determine the most suitable form for every new manure, as a string of well- known instances in the case of other manures abundantly proves. Fifty years ago, when the author’s father proposed the use of the potassium salts in the Stassfurt deposits, the chlorine compounds of potassium were not only con- sidered as of doubtful value, but even as harmful, while to-day three million tons per annum are used in agriculture all the world over.In the same way there was a time. when the use of Chili saltpetre was directly forbidden by the contracts of beet sugar manufacturers, while to-day it is considered absolutely infallible by all agriculturists, and in certain processes quite indispensable, The storm raised against calcium cyanamide has been lulled in the same way, and recently Professor Wagner of Darmstadt, one of the greatest authorities on agricultural chemistry, summed up his exhaustive researches I Experiments in the United Kingdom with the new manure have been made at Rothampsted, the Cambridge ‘University Farm, the West of Scotland Agricultural College, Harper Adams Agricultural College, the Highland Agricultural Society, the Dauntsey Agricultural School, and many other agricultural stations,IN THE PRODUCTION OF CALCIUM CYANAMIDE rog on the nitrogenous manuring of plants with Chili saltpetre, salts of ammonia, and calcium cyanamide as follows : “ The prospects for an advantageous use of calcium cyanamide are very bright, especially as regards its use for winter fruits.Calcium cyanamide can only be harmful in agricultural practice when it is submitted to abnormal decomposition through uizfavourable circum- stances. Such conditions are especially present in the cultivation of poor lands, such as high moorland and sandy soils which are inclined to be acid, and though rich in vegetable properties are poor in lime.I t is, however, well known that this soil behaves in an abiiormal maniaer to other nitrogenous maiaures. In order to prevent the unsuitable conditions of acid soil previous liming is necessary.” It was, besides, only natural that the manufacturers who were not in a position to turn out manure in bulk complying with all these demands should not have been very favourable. To-day, however, things are very different. A product is actually manufactured containing 20 per cent. and upwards of nitrogen-that is, considerably more than did the earlier products-which recently has further been submitted to a successful dust-removing process, is packed in air-tight sacks, and its efficacy appreciably increased thereby ; there can be no longer any doubt that calcium cyanamide is in a position to compete industrially with any other nitrogenous manure.In this connection the question of price is of the highest importance. Now, as the cyanamide industry has been perfected in the course of the last few years, it must be considered to form, on the basis of the percentage of available nitrogen, the cheapest, and therefore for agriculturists the most economical, manure of the present time. When the first consignments of calcium cyanamide were placed on the market the question of packing and storing was not fully understood. The result was that the product, containing a large amount of free lime, under the influence of atmospheric moisture was naturally converted into calcium hydrate. This caused such a large increase in the volume of the material that the jute sacks containing it burst.The theoretical proportion of nitrogen showed a decrease which was not ascribed, as it should have been, to the increase in total weight but was thought to be due to the fact that nitrolim lost nitrogen in some form or other when stored. Scientific research has shown conclusively, however, that calcium cyanamide may be kept stable for years without losing its nitrogen. The technical authorities have also taken notice of this fault, as mentioned above, and calcium cyanamide is now supplied by the manufacturers practically free from the influence of atmospheric moisture and packed in double paper and jute sacks.It has a further merit, which is of great importance in agricultural operations where elaborate appliances are wanting : calcium cyanamide can be mixed with most widely different manures without loss. For instance, mixed manures of cyanamide and potassium salts, basic slag, &c., may be mentioned which have been found eminently successful in practice. Some difficulty is met in mixing cyanamide with super-phosphate, as the free phosphoric acid combines with the free lime of the cyanamide, and is changed from the water soluble to the citric soluble form. To a certain extent this is not preventable, but the interesting and exhaustive work of Professor Hall, the well-known agricultural chemist and director of the Rothamstead agricultural farm, on this subject has proved that by observing certain conditions the mixing of super-phosphate with cyanamide can be easily accomplished, and is both successful and economical.What makes cyanamide especially valuable as a manure is its after-effects. I t is generally decomposed by the chemical and bacteriological constituents of the soil into ammonia, which becomes fixed by the vegetable mould, and106 T H E UTILISATION OF ATMOSPHERIC NITROGEN is not, as is Chili saltpetre, liable to be washed into the drains and so practically lost. For this reason cyanamide which has not been used during the jirst harvest is always available for the second. Researches on this subject show that the after-effects of cyanamide can be very considerable according to circumstances, a property possessed by no other nitrogenous manure.As regards the economy effected by cyanamide manuring the author will shortly describe the great number of tests which have been carried out for more than six years at agricultural research stations and by users in all parts of the world, and render the operation of cyanamide apparent by the help of photographs (see Appendix No. I.). As regards the part which cyanamide or iiitrolini plays in the soil various theories have been propounded. I t appears that when brought in contact with the ground calcium cyanamide is first decomposed through the action of the moisture and of the carbonic acid in the soil into free cyanamide and carbonate of lime according to the formula- CaCN, - H,O - CO, H,CN, - CaCO,.The free cyanamide will then, by absorbing water, probably be further decomposed into urea- The final product of this decomposition has been found to be ammonia, but later nitrate is produced through the nitrification of the ammonia. Special experiments have demonstrated that the process of transformation of calcium cyanamide or nitrolim is assisted by a host of microbes which are to be found in almost all cultivated soil. On this point very important and interesting investigation has been carried out quite recently by Dr. Lohnis and Saba- schnikoff I of Leipzig, and Dr. R. Perotti of Rome.z I t is, however, not only to the production of fertilisers that the scope of the new calcium cyanamide industry has been limited, for it has been also successfully extended to the production from nitrolim of a number of chemical substances to a great extent by utilising derivative forms of reaction long known to science.I am able to show you here some small samples of several of these derived products, all obtained from cyanamide of calcium. Although calcium cyanamide does not display the typical character of the cyanamides, it can, by melting with fluxes, be turned into calcium cyanide, which product can then be treated by well-known methods to yellow prussiate or cyanide of potassium or sodium. The molten mass obtained by melting nitrolim with a flux contains approximately an amount of cyanide correspond- ing to 25 per cent. KCN., the cost of the said molten mixture, to which we have given the name of “ surrogate,” being much less than that of an equiva- lent amount of pure cyanide of potassium, and the material having been shown by the investigations of English experts to be of equal efficiency with pure cyanide of potassium for the extraction of gold and silver.It appears particularly suited to the requirements of the countries where gold and silver are mined, as it can be produced without difficultyat the mine itself where it is to be used. The production of ammonia and ammoniacal salts from nitrolim, to which I have made reference previously, has also been further worked out and I Urttersuchungen iibev Kalkstickstofl und Stickstofkalk, von Dr. Alexis Sabaschnikoff. Dottore Renato Perotti, Su i bncteri delta diciandiainidc. Roma Typo- graphia Enriev Voghera, 1908.Berlin : 1908, Verlag von Paul Pavey.I N THE PRODUCTION OF CALCIUM CYANAMIDE 107 perfected on an industrial scale. You will readily understand that the ammonia obtained by heating CaCN, with water is very pure and free of empyrheuma. It is therefore particularly suitable for the production of pure ammoniacal salts as well as liquid ammonia (see Fig. 2). Further, the author would point out that a number of complex organic nitrogenous compounds have been derived from calcium cyanamide, and are already being produced on a manufacturing scale. Out of the great number of these I will only mention dicyandiamide (CNNH.),, for which there is an increasing demand in Germany for the manufacture of organic dyes, besides which there are urea CONH, and sulphourea CSNH,NH,.‘l’he author would also mention that one of the German companies is producing from nitrolim the salts of guanidine, such as carbonate and nitrate of guanidine, nitro-guanidine, and other salts, all of which should now gradually come into use on an increasing scale in the industries of organic chemistry, as the cost of production will be considerably lower when starting from calcium cyanamide than by the methods of manufacture hitherto employed. Recently attention has been paid to the use of nitrate From Steam- chest - - 1; Ammonia irz= F I G . 2.-DIAGRAM OF A PLANT FOR AMMONIA PRODUCTION FROM LIME NITROGEN. of guanidine, nitro-guanidine, and dicyandiamide as a ‘‘ deterrent ” for reducing the temperature of combustion with explosives and gunpowder. In consequence of the high contents of inert nitrogen in dicyandiamide (66.6 per cent.) it evolves a strong pressure when burnt in a gun, and in contradis- tinction to the other constituents of the explosive which contain more carbon and hydrogen, its decomposition produces but little heat.This peculiarity is of great importance in powder used with ordnance, such as cordite and filite, which, because of the high temperature of combustion, rapidly destroy the rifling of the barrels. With many powder mixtures the cooling action of dicyandiarnide is shown by the disappearance of the flash at the muzzle, so that on discharge both powder smoke and powder flash are done away with. The composition of the crude cyanamide of calcium made it appear likely that it would lend itself quite as well as yellow prussiate and potassium cyanide for use in case-hardening and tempering of iron and steel.Tests carried out to this end have confirmed this impression. It has been shown that by adding certain fluxes to the crude cyanamide of calcium a very high hardening effect can be produced. This new hardening mixture, under the name “ferrodur,” has been introduced on the market in Germany, England, and other countries, and its property of producing an extraordinary depth of the hardened surface without the material being at all deteriorated has already secured it a great number of friends.108 THE UTILISATION OF ATMOSPHERIC NITROGEN If I may ask your indulgence for a few more minutes, I would like to give you a short description of the method by which the nitrolim is being pro- duced in some of the factories, and to say also a few words on its position in the markets of the world.The carbide coming from the electric furnaces is ground, charged into retorts made of fire-proof material which are mounted in a furnace similar to gas-house furnaces (see Fig. 3). The nitrogen is then passed over the carbide at a temperature of from 800’ to 1,000~ C. The carbide used is of the same quality and percentage as that employed for lighting purposes, and the nitrogen consumed is obtained by fractional dis- tillation of liquefied air by the Linde system, or the so-called copper” process in which air has passed through heated copper particles. The copper takes up the oxygen and the free nitrogen passes to the furnaces.The resulting copper oxide is reduced in the same apparatus by treatment with reducing gases or vapours, and the copper which is recovered is then ready for a new cycle. In the Linde process the oxygen remaining after separation of the nitrogen may be utilised for any purposes. As soon as the carbide in the retorts is saturated with nitrogen, a fact which will be made apparent by the controlling gas-meter corning to a standstill, the calcium cyanamide is extracted from the retorts iii the form of a hard cake and cooled while the air is excluded. It is then ground into a fine powder and is ready for use. Nitrogen - 777 --t Flue FIG, 3.-DIAGRAM OF A LIME NITROGEN PLANT. During thc last year a new electric furnace has been developed for treating carbide with nitrogen, and is being universally adopted by all the new cyanamide factories in preference to the older retorts. This process is cheaper toinstall and to operate where the cost of power is low compared with that of the retort furnaces just described ; and notwithstanding that the average life of the retorts has been greatly prolonged, the new electric furnace is cheaper to maintain, possessing practically an unlimited life. Crude nitrolim contains about 57-63 per cent.of the pure cyanamide of calcium, so that its total contents in nitrogen will amount to roundly 20-22 per cent., the same as sulphate of ammonia. The material contains besides this about 20 per cent. of calcium oxide, 7-8 per cent. of silicious acid, iron oxide and alumina, and 14 per cent. of carbon, which imparts to the product its characteristic slate-black colour.Most carbide works obtain at the present time a yield of two tons of carbide per kw. year, and two tons of carbide will combine with practi- cally 500 kilograms of nitrogen in the form of nitrolim ; a power of two kw. or 2% horse-power is required per year for fixing one ton of nitrogen by the Frank-Car0 process. In addition thereto, about 5 horse-power is required for grinding and all other operations, If, therefore, it were pro-IN THE PRODUCTION OF CALCIUM CYANAMIDE 109 posed to substitute nitrolim for the nitrate of soda at present consumed in the world, it would require plants disposing of no less than 800,000 horse-power to do so. It goes without saying that before the process of making nitrolim could be developed on an industrial scale, its value as a fertiliser had first to be ascertained.And as it naturally took a number of years to complete the exhaustive agricultural researches instituted for this purpose sufficiently to make them conclusive, it will not surprise you, gentlemen, that it was only about three years ago that the question of putting up industrial works was attacked. About that time the Cyanid-Gesellschaft, in conjunction with two important Italian companies chiefly interested in the manufacture of calcium carbide, promoted, under the management of Cav-Morani, the founder of the Italian Carbide Industry, the Societa Generale per la Cianamide in Rome. The first plant on a large industrial scale was started about two and a half years ago at Piano d’Orta in Central Italy (Figs. 4 to 8), near to the Adriatic Sea, for a yearly production of 4,000 tons of lime nitrogen, and is just now being enlarged to a capacity of 10,000 tons.In addition to this, the Societa Generale is also about to appropriate a large water-power it owns in Italy for the erection of other works. One is ready to start in Terni in connection with the large carbide factories there, and another factory is in course of erection in San Marcel in the Val d’Aosta. There are at present in Austria-Hungary important cyanamide works in course of erection, all promoted by the Societa Generale of Rome. In Sebenico, in Dalmatia, at the carbide works one is being built for an initial yearly production of 4,000 tons. At Fiume, in Istria, works are also in construction for a similar output. At the present time a water-power installation of at least 50,000 horse-power is being erected at Almissa, also in Dalmatia, for the manufacture of this new artificial manure.The market for the products of these works will be the Balkans, Asia Minor, and Egypt, where, owing to the practice of irrigation, nitrolim will be of special value to agriculture. In France, the Soci6tk Francaise des Produits Azotks installed works a few months ago at N5tre Dame de Briancon (Haute Savoie), for the manu- facture of cyanamide, with an output of about 4,000 tons per annum. In the Rhone Valley in Switzerland the Sociktk Suisse des Produits Azotks has just opened equally important works. In Germany, the works at Westeregeln and Briihl on the Rhine are manufacturing 10,000 tons of nitrolim annually.It is interesting to mention that the works at Briihl for the preparation of carbide do not employ water-power, but produce the power required in the works themselves, using cheap coal in large quantities for this purpose. Another installation is that of the Brandenburgischer Carbidwerke for the preparation of nitrolim with an output of 2,500 tons per annum, near Bromberg, in North Germany, which is also completed, while the large works of the Cyanid Gesellschaft for an output of over 15,000 tons of nitrolim at Alz-Fluss, in Bavaria, are at present in construction. In the United States of North America the American Cyanamide Company has taken up the manufacture of nitrolim, and are constructing on the Canadian side of the Niagara Falls works of a present capacity of from 5,000 to 6,000 tons per annum, to be enlarged later to an output of 40,000 tons.It is quite natural that English enterprise should have given this new artificial fertiliser considerable attention. The North-Western Cyanamide Co., Ltd., with a capital of ; G I z o , o ~ , was incorporated in the middle of 1906 to acquire from the Societa Generale and work licences for the manufacturen o THE UTILISATION OF ATMOSPHERIC NITROGEN and sale of cyanamide in a vast territory comprising the United Kingdom, the Colonies, Protectorates and Dependencies (excepting Canada and Egypt), and a large portion of the North-West of Europe, viz., Norway, Sweden, and Belgium, with 30 per cent. of the consumption of Denmark, Germany, and Holland.The Sun Gas Company, now widely known as the Alby United Carbide Factories, Ltd., and their able Board of Directors, Mr. Albert Vickers, Sir Vincent Caillard, Mr. A. E. Barton, and others, took a leading part, with the co-operation and assistance of the Societa Generale of Rome, in the promotion of the North-Western Cyanamide Co., the Alby Company under- taking the erection of a new factory adjoining to that of the North-Western Company to supply them with the requisite carbide. These works, erected at Odda, which is situated at the head of the beautiful Hardanjer Fjord (Figs. 9 to 11), you will see in the accompanying picture, which shows the carbide works and the adjoining nitrolim works, which are the largest at present constructed.The capacity of the cyanamide works at present is 12,500 tons of nitrolim, and is laid out so as to be eventually enlarged to 50,000 tons. The nitrogen is produced by the largest Linde pump ever erected, with a capacity of 375 cubic metres (13,244 c. feet) per hour, and the latest electrical furnaces are there installed. The author wishes to point out here that the works at Odda, which produce 2,500 tons of nitrogen, only employ from 5,000 to 6,000 kw., whereas from the statement of Mr. Eyde' it appears that in the works at Notodden, in Norway, for the preparation of an equivalent amount of nitrogen in the form of nitrate of calcium, 25,000 kw. are required. In order to complete the review which the author has made of the works already erected for the preparation of nitrogenous fertilisers, it should be stated that the allies of the British in the Far East, the Japanese, are erecting in the south of the Kinskzu Island a works capable of producing 4,000 tons per annum, so that the manufacture of the new fertiliser will soon be localised all over the world. At the end of the present year works for a total production of over 45,000 tons of nitrolim will be in full swing, and in the course of next year there will be a correspondingly large increase in the means of production of this product. Though these figures may appear relatively high, they are quite diminutive in comparison with the continual increase in the demand for nitrogenous food for our agriculture, which in Germany alone at the present time shows an annual increase of 15,000 tons of nitrogen, which would, in the form of nitrolim, require a production of 75,000 tons.It would be an error to assume that the competition of calcium cyana- mide on the fertiliser market with Chili saltpetre, sulphate of ammonia, or Norwegian saltpetre can take on the character of a war of annihilation,as was the case with artificial indigo in respect to the natural product, On the contrary, Industry and Agriculture will welcome increasingly large supplies of nitrogen, tending to prevent the rising in the prices of the nitrogenous foods required for the development of plant life. It will be an especial satisfaction to you, gentlemen, to be assured that just at the present juncture discoveries in the field of electrochemistry have made it possible to succeed in the attempt to supply vegetation with its most valuable food, and that in the future the increasing demands for this form of nutrition by agriculturists can be satisfied, and mankind will, for the future, be able to manufacture unlimited bread and strength.Extract from the Archives of the Deutschen Landwirtschaftssrats, 3rd year, 1908.I N THE PRODUCTION OF CALCIUM CYANAMIDE 111 APPENDIX NO. I. SOME COMPARATIVE RESULTS OF THE APPLICATION OF " NITROLIM ' I TO CROPS. Spring Wheat.-Manuring experiments carried out by Professor Vincenti, of Ancona. Cwts. I. Manure applied per acre, superphosphate . . . . . . . . . 4'78 Non-nitrogenous manure as sulphate of ammonia . . . . . . . . . 0'79 non-nitrogenous ... { potassium sulphate .. . . . . . . . 1-59 above, plus nitrogenous i Chili saltpetre.. . . . . . . . . . . 0'40 Yield per acre : Grain, 9-56 cwt. ; straw 18.01 cwt. See Fig. 12. 11. Non-nitrogenous manure applied same as above- Plus nitrogenous nitrolim . . . . . . . . . . . . 1.36 cwt. Yield per acre : Grain, 9-56 cwt. ; straw, 18.17 cwt. See Fig. 13. Wiiztcr Wlzeaf.-Manuring experiments carried out by Professor Wagner, 111. Average of three years' crops in parallel experiments on areas of one of Darmstadt . hectare each, and identical applications of nitrogen. YIELD PER ACRE IN CWTS. Grain . . . . . . 10.20 16-77 16.34 16.89 So Manure. Chili Saltpdre. Sulphate of Ammonia. Nitrolim. Straw . . . . . . 20'64 37-21 34'43 35-06 With Chili saltpetre . . . . . . . . .. . . 2 4 6 With sulphate of ammonia . . . . . . . . . 2 5 4 With nitrolim . . . . . . . . . . . . . . . 2 19 14 PROFIT PER ACRE COMPARED WITH UNMANURED. s. d. See Fig. 14. IV. Wzizier Rye.-Manuring experiments carried out by Professor Wagner, of Darmstad t. Grain Straw YIELD PER ACRE IN CWTS. No Manure. Chili Saltpetre. Sulphate of Ammonia. Nitrolim. . . . . . . 7-01 15-38 15-30 15-06 . . . . . . 12-51 26.86 28-61 26.38 PROFIT PER ACRE COMPARED WITH UNMANURED. s. d. With Chili saltpetre . . . . . . . . . . . . I I I I I + With sulphate of ammonia . . . . . . . . . 2 6 I I $ See Fig. 15. With nitrolim . . . . . . . . . . . . . . . 2 5 82 V. Oak-Manuring experiments carried out by Professor Wagner, of Darm s tad t . YIELD PER ACRE IN CWTS. No Manure. Chili Saltpetre.Sulphate of Ammonia. Nitrolim. Grain . . . . . . 6.13 Straw . . . . . . 15.38 13.31 23'43 13-15 23'39 13.31 2 5 . ~ 8IIZ THE UTTLISATION OF ATMOSPHERIC NITROGEN PROFIT PER ACRE COMPARED WITH UNMANURED. .& s. d. With Chili saltpetre . . . . . . . . . . . . I 2 8 With sulphate of ammonia 1 4 3; With nitrolim 1 9 1% . . . . . . . . . . . . . . . . . . . . . . . . See Fig. 16. VI. Indian Cortz.-Manuring experiments carried out by Professor Menozzi, of Milan. COMPARISON OF EQUAL QUANTITIES OF NITROGENOUS MANURES-YIELD PER ACRE I N CWTS. Manure Used. Grain. Stalks and Leaves. ... 61.76 40 per cent. sulphate of ammonia 60 per cent. Chili saltpetre 1 . . . . . . f 28.61 See Fig. 17. . . . . . . . . . . . . . . . Nitrolim 29'25 57'78 See Fig. 18. VII. Potatoex-Manuring experiments carried out by Professor Steglich, of Dresden. Manure containing 674 lbs.of nitrogen per acre in the form of Chili nitrate, sulphate of ammonia, and nitrolim was applied. Preliminary manuring consisted of 44% lbs. phosphoric acid in thc form of 18 per cent. superphosphate and ++Q Ibs. of pqtassium monoxide in the form of potassium chlorate, and besides the equivalent amount of calcium cyanamide 12 cwt. of carbonate of lime were added. With Preliminary Chili Sulphate of Manures. Saltpetre. Ammonia. Nitrolim. Cwts. per acre . . . . . . 40.80 48.6 I 43'83 46.36 See Fig. 19. VI I I. Sugar Beet.-Manuring experiments carried out by Professor Strohmer, of Vienna. 468 lbs. superphosphate. 224 lbs. of 40 per cent. potassium salts. Preliminary manuring, per acre ...{ 1-35 cwt. sulphate of ammonia. 1-38 cwt. nitrolim. Nitrogenous manures, per acre ... { 1-78 cwt. Chili saltpetre. CROP I N CWTS. PER ACRE FROM THREE PARALLEL EXPERIMENTS. No Manure. Chili Saltpetre. Sulphate of Ammonia. Nitrolim. Roots . . . . . . 215.96 278'13 255'41 286'49 Sugar . . . . . . 36.10 47'43 43'72 50.08 See Fig. 20. APPENDIX NO. 11. GENERAL DESCRIPTION OF THE WORKS OF THE NORTH-WESTERN CYANAMIDE COMPANY, LIMITED, AT ODDA, NORWAY. As the works of the North-Western Cyanamide Company are the largest of the kind so far erected it will be of 'interest to give some details in connection therewith. Site.-This was chosen because of its proximity to one of the more abundantFIG. 4.-Piano d’Orte. General View of Works:FIG. 5.-Piano d'Orte.First Operation-receiving Carbide. FIG. 6.-Piano d'Orte. Manufacture of Nitrogen Gas.FIG. 7.-Piano d’Orte, Filling Charging Cylinders with Carbide, FIG. 8.-Piano d’Orte. Discharging Retorts.FIG. Io.-Odda Works, Interior of Furnace Room. FIG. II.-Odda. Inside Storage Lager.Odda Village. Cyanamide Works. FIG. g.-Odda. General View of Harbour, Village, North-Western Cyauainide Works, and Alby United Carbide Factories’ Works, Carbide Works. VOL. IV-T6FIG. 12.-Spring Wheat. Effect of Chili Saltpetre. (Professor Vincenti). FIG. 13.-Wheat. Effect of Nitrolim (Professor Vincenti). VOL. IV-T7Without Nitrate of Sulphate of Calcium cyanamide manure. soda. ammonia. (nitrolim). FIG. 14.-Comparative Results on Winter Wheat (Professor Wagner). Without Nitrate of Sulphate of Calcium cyanamide manure.soda. ammonia. (nitrolim). FIG. 15.-Comparative Results with Winter Rye (Professor Wagner).Without Nitrate of Sulp h ate of Calcium cyanamide manure. soda. ammonia. (nitrolim). FIG. 16.-Comparative Results with Oats (Professor Wagner). FIG. 17.-Indian Corn. With 10 per cent. Nitrate of Soda and 60 per cent. Sulphate of Ammonia. FIG, ~$.--Indian Corn with Nitrolim.Fundamental Nitrate of Sulphate. of Calcium cyanamide ammonia. (nitrolim). manuring. soda. FIG. ~g.-Comparative Results with Potatoes (Professor Steglich) Without Nitrate of Sulphate. of Calcium cyanamide manure. soda. ammonia. (nitrolim). FIG. 2o.-Comparative Results with Sugar Beet (Professor Slrohmer).I N T H E PRODUCTION OF CALCIUM CYANAMIDE 113 and less expensive sources of water-power to harness in Norway, situated in the valley of Tysse, between six and seven miles from the southern end of the Hardanger Fjord, and because suitable level land of sufficient extent for factory purposes existed abutting on the fjord to the east and south of the village of Odda.Power.-The harnessing of the natural water-power available in the Tysse Valley under agreement with the Alby United Carbide Factories, Limited, was undertaken by the Norwegian Tyssefaldene Company some two years ago. This Company also provided the land adjoining the village of Odda now occupied by the two companies. The power is derived from the last of the small chain of lakes in the Tysse Valley connected by the Tysse River, and fed from glaciers situated some ten miles from the eastern edge of the Hardanger Fjord. This lake is supplied from several lofty natural falls, the chief of which is the well-known Skjceggedalsfal.The water for power pur- poses is taken at about 40 ft. under the surface of the lake at its lower end, where a drowned dam has been constructed, enters a tunnel some three miles in length driven through the intervening hills, and is delivered to a series of 6-ft. pipes laid on the surface of the cliff overhanging the fjord. The generating station is built at the fjord level where there is an effective fall of 1,350 ft. upon the turbines. The permanent works, such as the tunnel, &c., are constructed for an eventual output of 80,ooo electrical horse-power, but the present installation is for the delivery of a quarter of that amount.Area Occupied by the Works.-The North-Western Cyanamide Works and those of the Alby United Carbide Factories, which supply the former with the raw material for the manufacture of their “ nitrolim,” occupy an area of some 34 acres exclusive of land on which their respective workmen’s villages are erected, the works of the N.W.C. Company occupying from 6 to 7 acres. OutpuL-The cyanamide works are designed for a yearly output of some 12,500 tons of a product testing between 20 and 22 per cent. of nitrogen. The carbide works are intended for an initial output of over 30,000 tons, and both works are laid out so as to be readily and progressively extended to four times their present capacity.BuiZdiizgs.-The main buildings of the cyanamide works occupy an area of 38,000 sq. ft., and consist of a suite of buildings comprising the carbide crushing house of three storeys, the electric furnace-room, the cyanamide crushing house of two storeys, the storage hoppers, with the cyanamide aerating-room on top with a storage capacity of some 8,000 tons, the packing- room, with the following isolated additional buildings : the Linde house, the transformer house, the repairing shops and store, and the drawing and general offices and laboratory. Works Comections.-An electric tramway connects the carbide and cyana- mide works and places them in communication with an extensive store at the export wharf, where two large ocean-going steamers can be berthed at once. The carbide works possess in addition an import quay, situated on the east side of the Odda River and connected with their works by an overhead cable- way, by-means of which the supplies of coal and limestone are delivered at the kilns, and the Cyanamide Company possess a short-length cableway connecting the furnace-rooms of the Alby Company with the upper story of the carbide crushing-room.Manufacturing Process.-The carbide broken into lumps received from the carbide works is delivered on the floor of the upper story of the carbide crushing house. There it is fed into a first set of crushers, traversing an intermediate set of crushers on the first floor, and thence passes through a double set of mills, where it is ground to the degree of fineness required, T8114 THE UTILISATION O F ATMOSPHERIC NITROGEN The whole of these operations are effected automatically with a special plant, which is entirely air-tight.From the fine grinding mills the carbide powder falls into a closed hopper under floor-level, from which the automatic lifting and conveying machinery delivers it into the furnace-feeding hoppers. The carbide power is then delivered into the recipients for the electric furnaces, of which there are 196 in the furnace-room, constructed for 300-kg. charges. These recipients are lifted and transported by an overhead electric traveller, and dropped into their respective furnaces in the furnace-room. The lids are then put on, fastened down, and rendered air-tight. Nitrogen gas is admitted under pressure. The alternating current is switched on, and the temperature of the contents raised to some 800' to 1,000' C.The whole process of converting the carbide into cyanamide takes on an average forty-five hours, including cooling. The movable recipients are lifted out, and their contents when cool are delivered into a double set of rnills in the cyanamide crushing-room, where they are once more reduced to a fine powder, which falls into hoppers below floor- level, and is lifted and delivered at the height of about 60 ft. on the floor covering the storage hoppers. Here it is fed into long, slow-moving conveying worms, over which is a trunking through which a current of air passes, travelling in the opposite direction to the conveyers. From the aerating conveyers it is distributed and dropped through openings into the storage hoppers, which are arranged on the unicellular system. From the hoppers the cyanamide is drawn, when required, through central horizontal sluice openings at the bottom of the hoppers communicating with conveyer pipes provided with endless worms, delivering into hoppers, from which it is lifted and fed into the tanks supplying the automatic weighing and sack-filling machines in the packing house. The whole of the plant above described has a maxiniuin capacity of some 30 tons Cyanamide per working day. The most important auxiliary building is the Linde house, where a complete plant duplicated in all essential parts for a production of 375 cubic metres of practically pure nitrogen is installed. This plant is too well known to require description, but it embodies all the latest improve- ments which the accumulated experience of many years has taught the patentees and makers to be desirable. The nitrogen as generated is dis- tributed through control metres to the various plants using it throughout the works without intermediate storage. There are also separate houses for the oil-cooled transformers (English make) of the total capacity of some 2,000 kw., which transform the current delivered by the generating station from 11,000 volts to the working pressure. The repairing workshop and store is provided with a smithy and a complete plate-bending, riveting, and cutting plant for the repair of the electrical furnace and various machine tools. The offices and laboratory are a large and convenient building of two storeys, with rooms for the manager, chief chemist, &c., on the upper floor, and areadjacent to a similar building belonging to the Alby Company at the road entrance of the works. The workmen's village is situated on the west side of the works at about half a mile distance, and accommodation is provided there for some forty families. Separate buildings for the accommodation of the other members of the works staff and foremen are also provided.

ISSN:0014-7672    

DOI:10.1039/TF9080400099

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

114 THE UTILISATION OF ATMOSPHERIC NITROGEN DISCUSS I ON. Mr. Henry E. P. Cottrell said he could add little to what Dr. Frank H e was pleased to be able to report that the Odda works of the had said.IN THE PRODUCTION OF CALCIUM CYANAMlDE 115 North-Western Cyanamide Company were starting operations that very day, and he thought that they would be able to supply all the nitrolim required at present within the sphere of operations reserved to their Company. Of course it .was difficult to get the British farmer to use new manures, but they had the support of the scientific agriculturalists, and they also had the support of those who best understood how to make the value of new manures under- stood by the British farmer. He believed that artificial nitrogenous manures had come to stay, for one reason because they were alkaline, and the ordinary nitrogenous manures were acid, and if applied constantly induced so-called sickness in the soil which the alkaline manure removed.Mr. Walter F. Reid congratulated the Society on having heard such an admirable Paper from Dr. Frank. He himself was much interested in the subject, having, during the last two years, carried out some tests on nitrolim. He had found that its value as a manure depended largely on the nature and state of the soil. For example, a sandy soil deficient in clay was too light for it, and it needed a certain amount of moisture to make it useful. It was therefore necessary that it be applied under suitable conditions. With regard to its use in explosives and in smokeless powder, he had made some imall-scale experiments, and had found it decidedly efficient in slowing down the explosion-perhaps rather too efficient.There was a distinct reduction in the flame and a cooling down of the gases. It was somewhat strange that a compound of nitrogen could be used to lessen the activity of explosives, themselves nitro-compounds. The uses of nitrolim as a raw material for the production of other chemicals; some of which were at present rare and expensive, should not be lost sight of, and on this account alone chemists should feel greatly indebted to Dr. Frank, to whose enterprises he wished every success. Dr. H. Borns hoped that the author would be able to add some information concerning electrical features. The diagrams and views did not explain any details.How long were the carbide and nitrogen heated together ? The electrical furnaces installed at Odda were apparently very small units arranged in a good many rows; could Dr. Frank tell them anything about the materials of the furnaces and their operations, and about the electrodes? When Mr. P. A. Guye had lectured on the fixation of atmo- spheric nitrogen before the Society of Chemical Industry two years ago, Dr. N. Car0 had stated that the cost of fixation would approximately be the same for the three processes, the Birkeland-Eyde, Guye, and Frank-Car0 processes ; did the figures then given still hold ? Dr. J. A. Voelcker (Royal Agricultural Society of England) defended the .British farmer in regard to the charge of conservatism and prejudice which had been made against him by the author of the Paper and by Mr.Cottrell, these having been put forward by them as constituting the principal bar to the utilisation of calcium cyanamide. The farmer, he (Dr. Voelcker) thought, was very wise to suspend his judgment. What were the circum- stances ? Here was a material, the claims of which were strongly advocated ; but if he applied for it, the farmer could not as yet be supplied with it, nor was he told what it would cost him. Throughout the whole Paper which they had heard read that evening there was no statement whatever as to where calcium cyanamide could be obtained, what the cost of manufacture was, or what the price to the farmer was to be. Could they, then, be surprised that he was not prepared to abandon the use of nitrate of soda or sulphate of ammonia for this new material? The farmer knew what these latter manures could do for his farm, and he knew what the nitrogen cost him per unit in them.If the advocates of calcium cyanamide could show him that116 THE UTILISATION OF ATMOSPHERIC NITROGEN he would get equally good results while purchasing the nitrogen at a lower cost per unit, they might be sure that he would not be slow to take it up. That calcium cyanamide was a perfectly good and useful material to employ had been shown already by experiments made with it. He himself had employed it, experimentally, on the Woburn Farm of the Royal Agri- cultural Society. There was no reason why it should not do well, but the whole question resolved itself into one of cost.Was the nitrogen to be procurable at a cheaper rate than in the form of nitrate of soda or sulphate of ammonia ? Until the advocates of calcium cyanamide could satisfactorily answer this, and also could tell the farmer where he could obtain it on a commercial scale, and not merely in experimental quantities, it was hopeless to look for any advancc and unfair to attribute this lack to the prejudice of the farmer. That the new material was any better than other nitrogenous materials, nitrogen for nitrogen, or better than its rival, calcium nitrate, he did not believe. Indeed, there were drawbacks to its use, as shown in the difficulties found in mixing it with superphosphate and other manures, and in the tendency for it to lose nitrogen on keeping.Here again the whole matter resolved itself into a question of relative cost of production, and the price at which calcium cyanamide could be put on the market. In the Paper mention had been made of other uses to which calcium cyanamide could be put. One of these was the manufacture of sulphate of ammonia. But it was clear that, for this to succeed, the calcium cyanamide must be capable of being produced at a considerably less cost than the sulphate of ammonia, and it had not yet been proved that this could be done. Much the same was true of calcium nitrate, a material which was not yet obtainable commercially, and for which no market price was quoted. And when the farmer found matters in this position, he could hardly be blamed that he did not show himself enthusiastic over this and other new discoveries, but that he preferred to wait until he knew what they were going to cost him.Mr. W. Murray Morrison also hoped that more information would be forthcoming regarding cost of production and power absorbed in the various stages of the process, together with a description of the plant employed. He asked whether it would be possible to make the cyanamide directly from the raw rnaterials in one operation, instead of having first to make carbide, cool it, crush it, and by a second process make the cyanamide. The exothermic nature of this second process apparently ren- dered the power absorbed very small, but it was obvious that a direct process would reduce the power, the labour, the capital eirpenditure, and other charges, He also asked whether a carbide of lower purity than that necessary for lighting purposes could not be employed.If so, the raw materials might be of a lower and cheaper quality, and the power absorbed by a lower grade carbide would be much less, the energy and the grade not following in direct ratio. The output mentioned on page 108, namely, z tons of carbide per kw. year, would seem to indicate a somewhat lower quality than the English standard carbide used for the production of acetylene. Did the author think that there would be sufficient demand for all the product in the market when all the works mentioned in the Paper were producing to their utmost capacity? He thought that the heartiest con- gratulations were due to the author’s father, and others associated with him, for the wonderful development of the cyanamide industry in so short a space of time.IN THE PRODUCTION OF CALCIUM CYANAMIDE 117 Mr.H. L. F. Vogel asked what the effect would be if a charge of carbide were not completely saturated with nitrogen. Would there not be danger of acetylene being evolved if the powder became moist ? The percentage of calcium oxide present in the cyanamide seemed very high. What was the degree of purity of nitrogen made in the Linde apparatus? Mr. Leon Gaster, in drawing attention to the statement of Dr. Frank that the Birkeland-Eyde process apparently required about four to five times as much electrical energy to produce a ton of nitrogen as was necessary in his own process, asked whether he was prepared, to give information on the following points : what proportion the cost of electrical energy bore to the total cost of production, how the cost of the various items, such as calcium carbide, and other materials employed, was distributed, and how they would influence the actual cost of cyanamide.In the Birkeland-Eyde process, it appeared that the cost of the electrical energy formed the most important item. It was probable that, in the case of Dr. Frank’s process, the cheaper the carbide was obtained, the lower would be the price of the cyanamide. The Chairman thought the Society were very fortunate in having such an interesting Paper as that to which they had just listened, and was sure that members were extremely obliged to Dr. Frank for coming over from Berlin to read this very valuable Paper.From an agricultural point of view the “fixation of atmospheric nitrogen” was of the very first importance, and although there was the process of Birkeland and Eyde, there was room, as the figures which Dr. Frank had placed before them showed, for a very large and increased output of nitrogenous products. There was no doubt cyana- mide had come to stay. The inventors were not to be blamed for being sanguine, and it was to be hoped that the product would be found to be of very great value to the agriculturalists. At the same time, they must be prepared to meet criticism, and this criticism would have to be disarmed by actual experimtntal demonstration. He thought it was all to the good that the agriculturists should be rather critical, because this was better than receiving the new invention with open arms and then finding out that it was not all that it claimed to be.A point that interested him very much was the large number of chemical products which it had been found possible to prepare using cyanamide as a starting material. He was sorry that Dr. Frank had been unable to tell them more about the new electric furnace, and hoped that it would not be long before he was in a position to give them the information which they desired. Dr. A. R. Frank : In reply to the questions of Dr. H. Borns, Dr. Frank replied that he regretted not being able to give at the time exact information with regard to the new electric furnaces which were being used at Odda for the manufacture of calcium cyanamide. He hoped, however, soon to be able to give the desired information, and he could already say that the method of working the furnaces was, like the carbide process, thermal.Since the lecture of Prof. P. A. Guye before the Society of Chemical Industry two years ago, on the fixation of nitrogen in the form of cyana- mide, substantial improvements and simplifications had been effected, so that the price estimated by Prof. P. A. Guye respecting the manufacture of cyanamide has now been considerably lowered. Dr. J. A. Voelcker raised a very important question from the point of view of sales of calcium cyanamide--e.g., the sale price. He (Dr. Frank) was only aware of the price which was asked for nitrolim in Italy and Germany. ‘This was at the present time 10 to 20 per cent. lower than that Was it due to oxygen being left in the nitrogen ? VOL.IV-T7*118 T H E UTILISATION OF ATMOSPHERIC NITROGEN for corresponding amounts of nitrogen contained in sulphate of ammonia or nitrate of soda. At this opportunity he would like to point out that the price for Norwegian calcium nitrate in Germany was higher than for the corresponding amount of nitrogen contained in Chili nitrate. He was pleased to learn from the statement of such a high authority as Dr. Voelcker that as a fertiliser nitrolim behaves as well as nitrate of soda and sulphate of ammonia, and that, as already asserted, the price of the material would be decidedly lower than that asked for other nitrogenous fertilisers, and he confidently expected that the English farmer would willingly consume the new fertiliser in large quantities.The difficulties already pointed out by Dr. Voelcker with regard to the mixing of nitrolim with superphosphate might, as stated in the lecture, be considered as solved, and he referred again to the interesting and conclusive trials made by Dr. Hall in this direction. Losses in the percentage of nitrogen contained in calcium cyanamide, which Dr. Voelcker had referred to, had been proved by con- clusive experiments to be non-existent. The decrease noticed earlier resulted from the increase in weight, but this difficulty also had been overcome by selecting special raw material and methods of packing. The regrettable fact pointed out by Dr. Voelcker, that nitrolim was not yet on the market in England, would soon be overcome by the North-Western Cyanamide Company, who would be able to furnish all the quantities required by the English farmer at no late date.In reply to Mr. Morrison's question, he must say that the experiment of preparing calcium cyanamide from the raw materials-lime and coal-had been carried out on a large scale for a number of years. Furnaces of a capacity of 500--600 kw. had been employed, but succeeded only in pro- ducing a 10-11 per cent. nitrogen product against that containing 20 per cent. and over yielded by the indirect method in employing carbide of calcium. The amount of power used in the direct process was originally not less than that required for the preparation of carbide and its subse- quent nitrification, but, on the contrary, was even higher.The cost of labour and apparatus for the direct process was not more favourable than that required for the indirect process, and this the more so when the consider- able disadvantage ensuing on the production of a low percentage product as compared with a high percentage product was 'considered. Notwithstanding this, the former method had not been entirely aban- doned; but it would take up too much time at this stage to enter into particulars of the trials made and the resulting conclusions. The quality of the carbide used in the preparation of cyanamide was essentially the same as that employed for lighting purposes as made at all the good European works, which, as stated on page 108, yielded 300 litres of gas per 2 tons of carbide per kilowatt per annum, and, in addition, satisfied the normal standard of carbide lighting.So long as the carbide works installed for the production of carbide did not give up their claim, under certain circumstances, to manufacture carbide for lighting purposes, iL would appear that to reduce the quality of the raw materials would render it un- marketable, although such a reduction for the purposes of cyanamide could undoubtedly be effected. It could not at present be decided whether the demand for nitrolim would embrace the production of all the works. When, however, one considered the steadily increasing demand all over the world for nitrogenous fertilisers, one must become convinced that many times the present anticipated production of nitroliin would find a ready market without the lcast difficulty, without taking into consideration the fact that at some time the Chili nitrate supply must become exhausted,IN THE PRODUCTION OF CALCIUM CYANAMIDE 119 In reply to the questions of Mr. H.L. F. Vogel, Dr. Frank said that an arrangement was now in use in all the large works to prevent nitrolim coming into the market containing carbide which would yield acetylene, or which had been damaged in course of manufacture. The nitrogen made by the Linde process attained usually a purity of 99'8 to IOO per cent. If, through any accident or during storage while being rectified, some oxygen happened to remain in the nitrogen, it would be absorbed during the transformation of the carbide. Concerning the remark of Mr. Leon Gaster, that the consumption of power for the preparation of equal quantities of nitrogen by the Birkeland- Eyde process was from four to five times as large as that required by the calcium cyanamide process, no objection could be raised. The proportionate cost of power to the entire cost of the preparation of calcium cyanamide depended essentially on the cost of power available for the manufacture of the carbide, as the cost of power for milling and grinding of raw and manu- factured materials was only an unimportant item. On the assumption that the average cost of electrical power available at the carbidc works was from ;G2 'to ;Gz 10s. per h.p. per annum, the cost of the carbide would amount to about 60 per cent. of the whole cost of preparing calcium cyanamide. By the Linde process the cost of nitrogen amounted to about 4s. Iod. per cubic metre. It was owing to these conditions that the cost of power and raw materials for the preparation of carbide exercised the greatest influence on the cost of calcium cyanamide.

ISSN:0014-7672    

DOI:10.1039/TF9080400114

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

RECENT DEVELOPMENTS OF T H E KJELLIN AND ROCHLING-RODENHAUSER ELECTRIC INDUCTION FURNACES. BY J. H A R D ~ N . ( A Paper read before the Faraday Society, June 23, 1908, Professor A. K. HUNTINGTON, Vice-President, in the Chair.) The object of this Paper is to discuss the rapid development of the electric induction furnace during the last two years. Before proceeding to discuss the practical improvements in detail, it will be interesting to touch upon one or two novel points of a purely physical nature. We will consider one which will be of general interest- THE (‘ PINCH ” EFFECT OF AN ELECTRIC CURRENT. Many people experimenting with electric arc and resistance furnaces have observed that when a current is passed through a bath of molten metal or electrolyte the current density cannot be raised to a very high limit without distorting the bath.If the current density is raised to a certain point, it is plainly seen that the metal carrying the current contracts violently, or, in other words, becomes pinched, the effect of which is that the metal on either side of the pinch swells up above the.average level of the bath. If the current is still increased, the pinch effect becomes so complete as to actually cause separation in the bath, thereby breaking the current circuit and causing a violent flash, together with rapid volatilisation. This is only a momentary effect, as the separate parts immediately flow together again, closing the circuit, when the same phenomenon repeats itself. Thus it was found impos- sible to pass an unlimited amount of power into the bath, although one might be well below the boiling point of the metal.The explanation of this pinch- ing is quite obvious. We have only to remember that conductors carrying current in the same direction have a mutual attraction for each other, and if we consider that the molten bath consists of an infinite number of elementary paths of current, it is natural that, as each one is attracting the paths in its immediate neighbourhood, there must be a tendency to compress the full section of the bath. If now, therefore, the bath is slightly contracted at any one spot, the current density will here be raised and the pressure will in- crease until finally the bath becomes so pinched that an actual break in the circuit may take place. Correspondents of the technical papers have discussed this question, and the point has been raised whether this phenomenon can also be observed in the induction furnace.Theoretically it is obvious that it should, for although the induced current is an alternating onc, it has for a given moment of time the same direction in each part of the path. We have taken observations under working conditions in a 60-kw. Kjellin furnace erected in London for experimental work. A small charge of pig- iron, consisting of about one-third of the full capacity of the furnace, was placed in the bath, and a current of 20 kw. was employed. As soon as the r 20 Of course, this is only momentary.RODENHAUSER ELECTRIC INDUCTION FURNACES 121 charge was fully liquid the pinching effect commenced, and the metal was seen to contract at a certain spot, raising the level of the metal on both sides of the pinch, which was sufficient to break the circuit, causing a flash, imme- diately after which the metal flowed together again, closing the circuit. The level of the metal immediately on each side of the pinched area rose about I+ in.above the normal level of the bath. It was found, on examination, that a small piece of slag was burnt into the bottom of the hearth at the point where this phenomenon occurred, thus causing the original reduction of area. Pieces of pig-iron were added to the bath, and as the depth increased the pinching slowly disappeared. It was found that if the original charge was about half of the full charge no pinching effect could be observed.Another striking feature is the resistance curve of the melt-that is to say, the curve obtained by taking the voltage at constant power across the terminals of the furnace during melting. Supposing we are starting the charge by means of a cold ring of welded or cast iron. Putting on a full load and keeping the kilowatts constant, we first find that the voltage rises above the normal for full load, and as the ring gets hotter the voltage still gradually rises until the ring becomes a bright red heat. From that point a decided drop in the voltage is noticed, although the power is kept constant and the weight of the charge is kept the same. As soon as the ring begins to melt the voltage again rises, but does not reach the same value as before the ring was red-hot.Now let us consider the cause of this result. The furnace is, as you know, nothing but a transformer with a short-circuited secondary. This latter must be placed some distance from the primary, owing to the thickness of the lining, cooling chamber, &c. We therefore have a certain amount of magnetic leakage, not only around the primary, but also round the secondary. The secondary is of iron, with comparatively high permeability, and we have therefore intro- duced an easy path for the lines of the stray field, hence the increased in- ductive voltage across the terminals. This is to a certain extent compensated for by the lower ohmic resistance of the ring ; but as the resistive coefficient of the latter is such as to increase with the temperature, the total resistance, measured across the terminals, will increase with the temperature, but the power factor will be lower during this period, which shows that it is not only the ohmic resistance that is increased, but also the inductive resistance.This is due to the fact that the permeability of the iron is also increased to a certain extent with the temperature; in fact, it rises very rapidly up to a temperature of about 840°C., when the permeability begins to drop very quickly, and reaches zero at about 920° C. In this interval between 840° and 920' (this figure will vary with various kinds of iron) the inductive resistance is rapidly decreasing, because the easy path for the stray field is checked, and the voltage across the terminals is consequently lowered. But in the meantime the ohmic resistance is steadily increasing, but more slowly than the change in the permeability ; therefore, the voltage will again rise, though slowly, until the temperature is reached at which the loss by radiation and the heat introduced balance each other.It may even increase somewhat above this point, owing to oxidation of the charge, but this increase is very slight. This is the explanation why some people were misled into believing that the increase of resistance in iron due to heat was not a straight line curve, (It may, perhaps, not be so, but the effect shown on the furnace terminal is certainly produced in the way stated-which can be proved by the watt- and voltmeter readings.) Now, turning our attention to the more practical side of our process, we recognise a new feature, which is likely to prove a distinct improvement, viz., the Rochling-Rodenhauser modification of the induction furnace.122 DEVELOPMENTS OF T H E KJELLIN AND ROCHLING- In the original Kjellin furnace some disadvantages are experienced when dealing with material which has to be refined and treated in very large quantities. For instance, when a charge of three tons or more is to be treated, the section of the b;tth becomes very large, thus causing a low resistance, whereby the power factor is lowered.If we try to increase the resistance by making the ring wider in diameter and of smaller section, the distance from the primary will be greater and the power factor again lower. Thus it becomes necessary to emp!oy a generator of very low periodicity for such furnaces, which is, of course, undesirable.Also the processes of de- sulphurisation and dephosphorisation are very tedious, as it is difficult to keep the slag sufficiently liquid for such purposes. Neverilzeless, this class of .furlaace will still hold its own, as it -forms an almost ideal crucible steel furnace. In the case of crucible steel we have seldom to deal with more than onc and a half to two tons at a time, and as it does not pay to use impure raw material, no refining is required, but plain melting and “ killing,” and for this class of work plain induction furnaces can be provided, which will answer very well at 15 to 25 cycles per second. But when it is desired to refine, say, a material smelted from inferior ores and decarburised in a converter, but still containing up to 0.1 to 0.2 per cent.sulphur and 0.05 or more phos- phorus, in quantities of five to seven tons, this plain induction furnace would not be so satisfactory. This was what was required for making rail and other similar steel at the Rochling’sche Iron and Steel Works at Volklingen, Germany, and therefore the engineers at these works, Mr. Rodenhauser and Dr. Schonawa, set them- selves to adapt the Kjellin furnace, and so arrived at the ‘( combined furnace.” This consists of a transformer furnace with two ring-shaped baths adjacent and communicating with one another, in the case of a single-phase furnace, and three such baths in the case of a three-phase furnace, with a square or rectangular hearth in the centre between the rings, with doors in front and behind, in exterior appearance very much like a Siemens open-hearth furnace ; but the principal feature is a heavy secondary winding of copper cables, placed around and co-axial with the primary (one on each leg of the core), sur- rounded by the rings forming the charge.These copper secondaries, consist- ing of a few turns only, are connected to conductive plates-they can hardly be called electrodes, for reasons given below-built into the furnace wall, two in front and two.at the back for a single-phase furnace. These plates consist of corrugated cast steel plates, and a compound of magnesite, dolomite, and tar is applied firmly over the corrugation. The plates do not conduct well when cold, but as soon as the furnace is charged with molten raw material they will act as a (( conductor of the second class,” and readily allow the current to pass.Thus about one-half of the power is transmitted to the charge by induction in the rings and the rest of the power through the side plates. As the copper secondary is placed very close to the primary, the leakfield is very much smaller ; in fact, three furnaces for one to one and a half tons ‘are ,now in operation with 50 periods at a power factor of 0.7 to 0.85, a result which could never be obtained with a plain induction furnace of a similar size, in spite of (( bifilar ” baths and other devices which have been tried. But fhis is not the chief advantage, as the same result may be obtained by other electrical means. A far more important gain is to be found in the metallurgical possibilities obtained with the new design. We know that for carrying out any refining process in steel we need a sufficiently liquid slag and ways and means of handling the same.This is to a certain extent obtained in some (( electrode furnaces,” where an arc plays between carbon blocks and the slag “blanket.” This, however, in some cases, has122 DEVELOPMENTS OF T H E KJELLIN AND ROCHLING- In the original Kjellin furnace some disadvantages are experienced when dealing with material which has to be refined and treated in very large quantities. For instance, when a charge of three tons or more is to be treated, the section of the b;tth becomes very large, thus causing a low resistance, whereby the power factor is lowered.If we try to increase the resistance by making the ring wider in diameter and of smaller section, the distance from the primary will be greater and the power factor again lower. Thus it becomes necessary to emp!oy a generator of very low periodicity for such furnaces, which is, of course, undesirable. Also the processes of de- sulphurisation and dephosphorisation are very tedious, as it is difficult to keep the slag sufficiently liquid for such purposes. Neverilzeless, this class of .furlaace will still hold its own, as it -forms an almost ideal crucible steel furnace. In the case of crucible steel we have seldom to deal with more than onc and a half to two tons at a time, and as it does not pay to use impure raw material, no refining is required, but plain melting and “ killing,” and for this class of work plain induction furnaces can be provided, which will answer very well at 15 to 25 cycles per second.But when it is desired to refine, say, a material smelted from inferior ores and decarburised in a converter, but still containing up to 0.1 to 0.2 per cent. sulphur and 0.05 or more phos- phorus, in quantities of five to seven tons, this plain induction furnace would not be so satisfactory. This was what was required for making rail and other similar steel at the Rochling’sche Iron and Steel Works at Volklingen, Germany, and therefore the engineers at these works, Mr. Rodenhauser and Dr. Schonawa, set them- selves to adapt the Kjellin furnace, and so arrived at the ‘( combined furnace.” This consists of a transformer furnace with two ring-shaped baths adjacent and communicating with one another, in the case of a single-phase furnace, and three such baths in the case of a three-phase furnace, with a square or rectangular hearth in the centre between the rings, with doors in front and behind, in exterior appearance very much like a Siemens open-hearth furnace ; but the principal feature is a heavy secondary winding of copper cables, placed around and co-axial with the primary (one on each leg of the core), sur- rounded by the rings forming the charge.These copper secondaries, consist- ing of a few turns only, are connected to conductive plates-they can hardly be called electrodes, for reasons given below-built into the furnace wall, two in front and two.at the back for a single-phase furnace.These plates consist of corrugated cast steel plates, and a compound of magnesite, dolomite, and tar is applied firmly over the corrugation. The plates do not conduct well when cold, but as soon as the furnace is charged with molten raw material they will act as a (( conductor of the second class,” and readily allow the current to pass. Thus about one-half of the power is transmitted to the charge by induction in the rings and the rest of the power through the side plates. As the copper secondary is placed very close to the primary, the leakfield is very much smaller ; in fact, three furnaces for one to one and a half tons ‘are ,now in operation with 50 periods at a power factor of 0.7 to 0.85, a result which could never be obtained with a plain induction furnace of a similar size, in spite of (( bifilar ” baths and other devices which have been tried.But fhis is not the chief advantage, as the same result may be obtained by other electrical means. A far more important gain is to be found in the metallurgical possibilities obtained with the new design. We know that for carrying out any refining process in steel we need a sufficiently liquid slag and ways and means of handling the same. This is to a certain extent obtained in some (( electrode furnaces,” where an arc plays between carbon blocks and the slag “blanket.” This, however, in some cases, hasFIG. 3.-The Rochling-Rodenhauser 3-phase InductionFurnace-1 Ton. 60-kw. Experimental Kjellin Furnace-London.RODENHAUSER ELECTRIC INDUCTION FURNACES 123 proved troublesome, the drawback being that the temperature must be extremely and unnecessarily high at the spot where the arcs are playing, which may not be without certain disadvantages to some steels.If we try to dip the carbons direct into the molten metal, we find that they are consumed at once, in such case contaminating the steel, which is, of course, difficult to avoid. The conducting side plates before mentioned are of quite a neutral nature ; in fact, some plates, which had been in constant use, day and night, for three months were so little corroded at the end of that period that the loss of the plates, calcu- lated per ton of steel, was hardly determinable. Part of the power is induced in the rings, thus heating the charge, and the rest passes through the side plates, to such an extent only as experience has proved to be necessary in order to obtain a sufficiently liquid slag.The ring-shaped part of the bath is covered with bricks, at a height below the level of the charge in the centre bath. Thus no slag can enter into the rings, and as it is the slag which is injurious to the lining, the rings need hardly any repair during a long run, whereas the rectangular bath in the middle is easily accessible, and can easily be patched out. The lining is simply calcined magnesite or dolomite, mixed with tar, and stamped in hot. It has been %id that the use of these steel side plates would be equal to a return to the old system of electrodes, with all their disadvantages, but it is evident from what has been stated above that this is not so, as practically no consumption whatever of these plates takes place, and they can hardly be called ‘‘ electrodes ” in that sense of the word.After the lining is stamped in, the tar is burnt out (either by heating a cast steel ring or pouring a small quantity of pig iron into the hearth), leaving behind a sintered mass, forming a solid brick of basic lining. The pig iron is teemed for treatment in the Bessemer converter, and a fresh charge is given, which is tapped direct from the converter. It is more economical to burn out the carbon and the silicon in the converter, before refining from phosphorus and sulphur. The larger furnace at Volklingen will take a charge of four tons. Calcined lime is added to form a suitable slag ; this slag sometimes also contains about 6 per cent.of magnesia. In case of need, a small quantity of fluorspar is also added, to act as a flux, but this is not always nwessary. Plate scale from the rolling-mill is added for decarborising. In this condition the slag will take up the phosphorus very readily, after which it is made more viscous by applying cold lime and drawn off through the slag door by a slight tilting of the furnace. It is essential for a successful dephosphorisation that the charge should be what is called “ hot brittle”--i.e., have an excess of oxygen, in order to prevent the phosphorus wandering back into the charge again. After removing the slag which contains phosphorus, ferrosilicon or carbon is added, forming SiO, or CO, thus depriving the charge of the oxygen.It has been found that the adding of ferrosilicon will shorten the time of the de-oxidation ; thus, if power is cheap, the cheaper carbon may be employed, and in the case of dearer power it is better to use the ferro- silicon. As soon as the dephosphorising is effeoted this first slag is entirely removed, and a fresh slag of lime only is formed, which, when the temperature is raised, acts as a desulphuriser in forming iron sulphide, But this is not so in the case of the combined furnace. Let us now follow up the progress of the operation.124 DEVELOPMENTS OF THE KJELLIN AND RuCHLING- The oxygen is also driven out in this operation, probably partly by combus- tion of the ferro-silicon (or carbon), whereby the temperature is increased, thus forming calcium carbide, and partly by adding a small quantity of other reactive agents.After this, the maximum power is applied, in order to drive out the last trace of oxygen, and as soon as no more gas bubbles are seen to leave the charge a test piece is taken out and forged. If too soft for the purpose, some coke powder is thrown in until the right proportions are arrived at. As a rule the operation is finished in one and a quarter to two hours, but if necessary the steel can, without disadvantage, be kept in the furnace for ten hours or more. It is thus possible to treat a material which contains up to 0.1 per cent. phosphorus and 0.1 per cent. sulphur or more so that a product containing 0*006 per cent. phosphorus or less and o*oz per cent. sulphur or less and from 0.5 to 0.1 per cent.manganese and 0.01 silicon will be obtained. As to the power consumption, if the furnace is charged with molten material from the converter, the consumption is from 125 to 150 kw. hours per ton of finished material. This, of course, depends upon the quality of the raw material, but 130 kw. hours may be taken as a good average for rail steel. The finished product is especially distinguished by its great strength, equality, and homogeneity. In fact, rails have been made with a much higher bending and breaking point than ordinary Bessemer or Thomas rails, and these rails command from 25s. to 45s. per ton more than ordinary rails, owing to their greater durability. There is no necessity to give a large quantity of figures as to strength, &c., of this material, but a few may be given below.ANALYSIS AND PROPERTIES OF ELECTRIC RAIL STEEL. Exhibited on the Meeting of the Furaduy Society. NO. - I 2 3 c. 0'55 0'50 0'55 I I 0'0941 Oq30 Si. S. P. 0.30 0.03 0.05 0'25 0.025 0.05 0.29 0.03 0.04 Tensile Strength. Ton, Square Inch. 53'2 52.0 52'5 Elongation Per Cent. 8 Inches. I 8.5 I 9.0 I 7-0 Contraction. Per Cent. 31'4 26.7 30.8 Low Carbon Electric Steel. 0*086/ 0*024( Traces/ 23.22 I 36.0 1 71.5RESULTS OF REFINING IN THE COhfBINED FURNACE. MECHANICAL PROPERTIES. CHARGING MATERIAL. No. I 2 3 4 5 6 7 8 9 I0 I1 12 13 I4 15 16 17 18 I9 20 21 - C. 3.400 P. 0048 0.048 0.064 0.060 0'077 0.042 0.098 0.057 0.07 I 0.048 0.049 0.070 0.060 0.085 0'045 0.043 0069 0.060 0.050 0.08 I 0.074 hln. 0.440 0'520 0.528 0.580 0.592 I *050 0.488 0.420 0.580 0'540 0.450 0'340 0.440 0.460 0'496 0.476 0.464 0.460 0.500 0.460 0.540 S 0.137 0.08 I 0.089 0084 0.089 0.097 0.073 0'105 0'057 0.08 I 0'073 0.105 0.065 0'073 0.057 0'12 I 0.078 0.081 0.08 I Si. 0'15 C. 0.093 0.070 0.152 0'144 0'334 0'397 0.690 0.892 0.928 0'939 0.972 I -04 1.05 0'201 0.854 I '00 0*080 0.620 0.750 1-170 0'2 I2 P. 0'022 rraces 0.025 0'0 I 8 0.024 0'0 I5 0.023 0.016 0'0 I 5 0.016 0.016 0.0 I 8 0.026 0'022 0'0 I2 0'01 I FINISHED h1ATERIAL. b1 n. 0.420 0.420 0.420 0'435 0'495 0.540 0.667 0'347 0.352 0'376 0.360 0.3 I 8 0.300 0'352 0.300 0330 Steel AIloj 0.01g 0.016 0.025 0'022 0'022 0.253 0'505 0.880 0,283 0.320 S . 0.024 0.032 0.024 0.026 0'035 0.024 0.016 Traces 0.016 0'0 14, Traces 0.016 Traces 0.016 0.01; 0'020 0.032 0'02 8 I'races 0.016 0.0 I 6 Si , 0'014 0.24 0.29 0.3 I 0.38 0'34 0.19 0.3 I 0.13 0.25 0.16 0.18 0'010 0'12 0'22 0'20 0.14 0'26 0'79 0.4 I 0.30 Cr. Ni. Tensile Strength. Tons, per Square Inch. 22.5 23-8 31'5 3 1.0 32.8 39'75 41'4 45'2 40'3 61.5 65.0 72.1 Elongation per cent. Total length 8 inches. 37'0 40.0 33'5 28.5 31.0 27'5 26.0 I 9.0 17'5 I 2.5 7'0 10'0 Contraction per cent. 70.2 69.3 62'3 51'5 53'2 41'3 32'9 48.5 46.4 23'5 49'2 23'4

ISSN:0014-7672    

DOI:10.1039/TF9080400120

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

126 DEVELOPMENTS OF THE KJELLIN AND ROCHLING- DISCUSSION. Mr. F. W. Harbord considered the modified Kjellin furnace described in the Paper a useful improvement on the original furnace. He did not, however, see how a 7-ton furnace could make rail stcel in competition with a modern converter of 10 to 14 tons capacity, or a 50-ton open- hearth furnace. The electric process, in fact, was really a refining process, and should be used as such, either in conjunction with a converter or an open- hearth furnace ; this was the most promising future for the electric furnace, in connection with steel manufacture. He did not think the etched rail sections they had seen proved very much as regards the uniformity of the electric as against open-hearth steel. He would like to know whether this steel was actually being used for rails.As regards the high breaking stress of the material, there was no difficulty in making such steel, containing, for instance, only a trace of phosphorus, provided pure materials were used, as they were here. The induction type of furnace was not, in his opinion, particularly well adapted for impure materials, and its real advantage was, that it worked in a neutral and not an oxidising atmosphere. It was a crucible furnace, in which ton lots instead of pound lots could be made. He was much interested to find that calcium carbide was produced in the furnace in situ. He had seen-he believed in an Hkroult furnace- carbide added to deoxidise the bath, with extremely good results. Mr. E. Ristori said that the title of the Paper gave a wrong itnpression of the type of furnace the author had described, which was not an induction, but a combined induction and resistance furnace, and it appeared to him from the description that most of the work was done in the resistance portion of the furnace.The induction type of furnace, he considered, was only suitable as a substitute for crucibles, but was not capable of refining steel, viz., of making good steel out of impure raw materials. This could only be done by means of the resistance type of furnace, such as the Hkroult furnace, and he noted that the inventors had to fall back on the resistance principle when they wanted to refine steel. He would like to ask the author if he could give an analysis of the raw materials used and of the finished steel in order to see what amount of refining could actually be done in practice by the type of furnace described.Dr. H. Borns : We have reason to thank Mr. Hard& for his paper. The recent discussions on the performance of electric iron and steel furnaces, notably in Germany, have helped us to a good deal of useful information, and Mr. Hardkn has now made some valuable additions. May I ask a few questions? What was the depth of the metal in the trough when Mr. Hard& observed the pinch effect? I should also feel obliged if Mr. Hard& could explain more fully how the metal is kept at a somewhat higher level in the central portion of the Rodenhauser furnace than in the ring. I t is said that the iron will, in the annular trough, assume an inclined position as if it were under the influence of a centrifugal force ; the effect is aScribed to the combined action of magnetic stray fields and of gravity.IS the surface always inclined, and does Mr. Hardin accept the suggested explanation ? Mr. Harbord has already referred to the part played by calcium carbide in the purification of the steel; Hkroult and Eichhoff make a point of the action of the carbide, especially with regard to the removal of the sulphur. Mr. Hardin tells us that the carbide must be formed in situ, and that. he All rails varied very considerably in this respect.RODENHAUSEK ELECTRIC INDUCTION FURNACES 127 noticed the smell of acetylene. Have we any real evidence of this formation in situ? Dr. Richard Seligman said that as the time was so far advanced he would not detain the meeting longer than to put one or two questions to the author.He had been extremely interested in the author’s remarks on the “pinch effect,” a phenbmenon which was of importance to all of them who had to pass heavy currents through molten conductors, and one which had a habit of cropping up in the most unexpected way. Could the author tell them at what current density the “effect ” was observed in the case of molten iron? The author stated that the “sticky” property of iron was due only to high temperature, and gave as his reason the fact that when fresh metal was added to the bath the stickiness entirely vanished. But was the effect of the added metal merely to reduce the temperature of the bath ? Was it not possible that the ‘( sticky” metal was merely diluted by the addition of the fresh metal, or had the author made the experiment of lowering the temperature of the bath by other means in order to see whether the stickiness disappeared in the same way? Dr.J. A. Harker joined the previous speakers in congratulating the author on the many interesting facts revealed in the Paper. The Grondel- Kj ellin Company had last year kindly presented a small experimental induction furnace, taking some 25 kw., to the National Physical Laboratory. He hoped this would sooii be working, they had been obliged to erect a special building to place it in, for it was intended to study in it some of the interesting questions raised by the author-he would instance the increased resistance of iron at high temperatures-and to determine the physical constants of iron and steel and other metals at high temperatures, accurate data which we were so badly in need of.The speaker also referred to some experiments in which he had noticed the “pinch” effect alluded to in the Paper. In conjunction with Mr. W. A. Price he had attempted to use a resister of molten tin as the heating medium for a bath of fused salts. If the resister were made in the form of a gridiron, the metal being contained in channels machined on the surface of a fire- brick, it was found that at high-current densities, using alternating current of fairly low frequency, severance of the conductor always took place, rendering the method incapable of application. Even with a straight channel, where magnetic effects of the current would be less serious, the slightest irregularity in the shape of the channel holding the metal apparently determined the point of severance.The current densities in these experi- ments would be from 5,000 to 15,000 amperes per square inch, and the conductors about & square inch in cross-section. I t was not found possible to employ the method as originally intended. For experimental purposes it was impossible to overrate the advantage of being able to melt metals and other substances in a neutral atmosphere, such as one had in the induction furnace. The new metallic filament lamps were calling out for such a furnace which could be worked in vacuo. Tungsten, for instance, combined with almost any gas that came near it, and a vacuum induction furnace was therefore a necessity.Did the author know whether the Colby furnace, for which American patents were taken out some years ago, was being used for melting platinum and other refractory metals in vacuo? Dr. J. Harden, replying to Mr. Harbord, said the steel had been used commercially for various purposes, among others for automobile work (samples exhibited). As regards rails, the Prussian State Railways had128 DEVELOPMENTS OF T H E KJELLIN AND ROCHLING- recently ordered considerable quantities for points and crossings, paying some 40 marks a ton more than for ordinary steel. Those who could appre- ciate this fact would recognise that there must be good reasons for such willingness to pay an extra 40 niarks a ton. When discussing the extent to which the steel had been used, it must be borne in mind that the large furnace described was the first of any size built.-VVith reference to the presence of calcium carbide, if ready-made carbide is added to the slag no action takes place (it may even be injurious to the process) provided that the tem- perature is not high enough lo decompose the carbide, in which case desulphuri- sation is observed. The author’s theory, however, is that when lime, CaO, is added to the steel while the latter contains an excess of oxygen, a deoxi- dising material, such as carbon, or, still better, ferrosilicon, also being present, the oxygen then acts upon this substance in a combustive manner, whereby the temperature is considerably increased. Therefore, with aid of the carbon present in the steel, the lime is partly decomposed into calcium and carbon monoxide ; the free calcium combines instantly with the sulphur, forming calcium sulphide, while a portion of the calcium, at this temperature, takes up some of the carbon present, thus forming calcium carbide, both being found later in the slag.Consequently it is not the carbide per se which acts as a desulphuriser or deoxidiser, but its presence is merely an indicator that the desulphurisation has actually taken place. It is the ferrosilicon, &c., which deprives the steel of its oxygen, thereby raising the temperature so that the above reaction may take place. Hence also the necessity of exces- sive heat when trying to desulphurise by means of ready-made carbide, which will have to be decomposed at high temperature; this may certainly be carried out in an arc-furnace, but is to the author’s mind a waste of power, The excessive formation of carbide in any steel furnace must be a waste of power, as it is always an expensive process; it is only necessary to form sufficient carbide to indicate that the desired reaction has taken place.In the case of an arc furnace, with a very high temperature under the arcs, the possibility exists that the deoxidation may be effected by means of lime only (or carbide) ; i.e., if the lime (or carbide) is decomposed by the heat, part of the free calcium may form calcium sulphide, and, as soon as the critical point is again reached, oxygen may be taken from the steel, re-forming lime together with the calcium present in the slag.Of course, no free calcium will ever be found in the slag after it has been withdrawn from the furnace, as it is oxidised instantly by the atmospheric oxygen. The above theory is, of course, very difficult to prove, but many observa- tions tend to indicate that it may be right, and it would certainly be very desirable if the matter could be fully cleared up. Referring to DP. Harker’s remarks, the interesting little furnace at the National Physical Laboratory was the one that had been in use at the Sheffield Exhibition. It had a power- factor of 78 to 81 per cent., and worked with a frequency of 210, the core being very narrow, as it was especially adapted for melting rare substances. In one form of this the windings were outside the crucible, and on this account the power-factor was low.No large furnaces of this type had been built, and the Colby Company was now working in conjunction with the Kjellin Company in America. He knew of no vacuum induction furnace, but he thought that although considerable mechanical skill would be called for there was no serious diffi- culty in the making of one. The best vacuum electric furnace he knew of was that of the General Electric Co., U.S.A., designed by Mr. Arsem. In It would melt 7 lbs. of iron in twenty minutes. The Colby induction furnace had been mentioned.RODENHAUSER ELECTRIC INDUCTION FURNACES 129 this boron carbide had been made and the existence of two carbides had been proved. Wolfram may be produced in a crucible lined with wolfram oxide.In reply to Mr. Ristori‘s remarks, the Kjellin furnace was originally only a melting furnace, but when it was found necessary to refine it was modified to the combination form ; but as, generally speaking, two-thirds of the power was inductive-depending on the degree of refining required-and at the least one-half, it was not accurate to call it a resistance furnace. Moreover the electrodes were neutral and unacted upon. Replying to Dr. Borns, the depth of the bath, when the pinch effect was observed, was about I$ to 2 inches. As to the difference in level, this was very slight only, and effected by brickwork, covering the rings and secured by bandage of iron. As regards the level on the surface in a Kjellin furnace, the magnetic forces are tending to drive the metal outward, widening the ring, thus raising the level on the outer wall ; but the thermal effect, caused by higher current density in the inner parts, will make it rise still more on the inner wall, where also the slag may be mostly observed. In reply to Dr. Seligman, the bath section was about I B x 2 in. and the current about 9,000 amps., but the density might have been higher, due to the obstruction which started the pinch. The “stickiness” of the metal in the observed cases was certainly due to temperature only, and it was overcome by cooling.

ISSN:0014-7672    

DOI:10.1039/TF9080400126

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

T H E HEATS OF COMBUSTION OF’ ALUMINIUM, CALCIUM, AND MAGNESIUM. BY F. E. WESTON, B.Sc., AND H. R. ELLIS, B.Sc. ( A Paper read before the Faraday Society.) The values given by various experimenters for the heats of formation of Al,O,, CaO, and MgO differ very considerably, as is shown in the following table. I. Mg+O=MgO- Heat Evolution. Authority. 148,000 calories ... 143,300 ,, ... Beketoff. 143,400 ,9 ... Electrochemical and Metallurgical Industry, 6-8. 151,900 calories ... 131,500 ,, ... Thomsen (see L. and B.). 145,000 7 ) ... Moissan. 131,648 ,, ... Dr. Strauss, Minet, Produciion of Al, p. 209. 130,900 7 , ... Thomsen. Dr. Strauss, Mirzet, Production of AE, p. 209. 11. Ca + 0 = CaO- A. Guntz and H. Bassett, jun., C. R., 1905, 140, 863,864. Guntz used pure Ca and formed pure compounds, from which he deter- mined the heats of solution ; this, of course, introduces complications, leading to various corrections.Forcrand, using pure CaO from Ca(OH), and deter- mining heats of solution, obtained the same value as Guntz (C. R., 1908, 146 217-220). Thomsen used CaO prepared from calcium nitrate, and Forcrand (C. R., 146, 217-220) points out that the low value obtained was probably due to impurities ; consequently all values based on Thomsen’s results will be low (see also J . C. S., Abst. II., 155, 1908). Moissan’s result was obtained by direct determination of the heat of combustion, and therefore is less liable to error than those. results obtained by indirect means. 111. 2 A1 + 3 0 = Alz03- 386,988 calories ... 380,200 ’, ...Thomsen (see L. and B.). 392,610 ,, ... Richards, Electrochemical and Metallurgical Calculating these results for I gram-atom of 0, they become 128,996, 126,733, and 130,870 respectively. On account of the great divergence in the above numbers, experiments were carried out with a view of ascertaining as far as possible which element has the greatest heat of combustion by examining the reducibility of the oxides of aluminium, calcium, and magnesium by the metals Al, Ca, and Mg respectively. Dr. Strauss, Miizet, Production of AZ, p. 209. Zitdustry, 6-8. 130HEATS OF COMBUSTION OF ALUMINIUM, ETC. 131 From the foregoing tables it will be seen that the average value of the heat of combustion of Mg is 145,000 calories, that of Ca is 137,000 calories, and that of A1 is 129,000 calories; hence from the theory of greatest heat development Mg should reduce CaO and A1,0,, Ca should reduce A1,0, and not MgO, and A1 should not reduce CaO or MgO.Now Goldschmidt (Minet, Production of AZ, p. 213) has already shown that A1 can reduce CaO, and Dr. F. M. Perkin has succeeded in reducing A1,0, by Ca ; but it was thought advisable to repeat these experiments in order that a complete comparison could be made between the various reductions when carried out under the same conditions. EXPERIMENTAL. Series I . The Action of A1 Powdei upon Al,O,, MgO, and CaO respectively. The A1 powder was the same as that used by the authors in their previous work (see Trans. Far. SOC., vol. iv., 1, 1908). The A1,0, was prepared by ignition of pure ammonia alum.The MgO was made by ignition of precipi- tated magnesium carbonate, and was heated for some hours in a muffle at 1,000' C. and was in an extremely fine state of division. The CaO was obtained by ignition of marble, finely powdered, passed through a 40,000- meshed sieve, and the resulting powder again heated at 1,000~ C. for one hour. This experiment was first carried out by Duboin (C. R., cxxxii., No. 13). The mixture readily reacts with a fuse, forming a blackish- grey product which dissolves in HCl with the evolution of H ; it contains, probably, a suboxide of aluminium, but very little nitride. The mixture, contained in a Hessian crucible, would not react in the cold, even when a fairly large fuse was used ; when heated over a bunsen burner for two hours (the bottom of the crucible was at a dull red heat), a fuse again brought about no reaction.The crucible was then placed in the muffle at its hottest part ; after two minutes, the crucible then being bright red, action started at the surface and then very rapidly spread throughout the whole mass, giving a somewhat violent reaction. The reaction consisted first of the oxidation of the surface A1 by the air, and the heat produced by this reaction, together with the heat supplied by the furnace, brought about the reduction of the CaO by the Al; this reaction appears to us to be endo- thermic, since it was only possible to bring about the reaction under the conditions stated. The product of the reaction consisted of a hard, black, fused mass, and contained free Ca, calcium aluminate, free A1 (and possibly some A1,0), A1,0,, and CaO ; it also contained a small amount of nitride and carbide.Estimation of Free Ca and AZ.-The finely powdered substance was treated with cold water and the gas evolved collected and analysed. From volume of H evolved the percentage of free Ca was calculated ; a small quantity of C,H, and CH, was found present. After treatment with water, HC1 was added and the process repeated. I. A1,0, + 4Al. 2. 2 A1 + 3 CaO. Per cent. free Ca = 8-3 ,, ,, free A1 = 6-1 ,, ,, nitrogen = 0.375 (as nitride) Hence it is evident that A1 powder can reduce CaO at high temperatures, and it is probable that the reaction 2 A1 + 3 CaO +3 Ca + A/O, is a rever- sible one and that a stage of equilibrium is reached under the above con- ditions.132 THE HEATS OF COMBUSTION OF ALUMINIUM, 3.2 A1 + 3 MgO. The reduction could not be brought about even at the highest temperature attainable (e.g., about I , 100" C.) ; the only change obtained was a superficial oxidation of the A l ; the contents of the crucible were otherwise unacted upon. Hence it appears that the heat of formation of MgO is greater than that of CaO. Series I I . I. 3 Ca + A1,0,. The calcium was first converted into fine shavings in a lathe, and these were then crushed as small as possible in an iron mortar, and that portion which passed through a Izo-meshed sieve was used. The mixture, in a Hessian crucible, would not react in the cold even when a moderately large fuse was used, but on heating with a bunsen burner until the bottom of the crucible was at a dull red heat, a violent reaction took place and the larger portion of the contents of the crucible was ejected.From the way in which the reaction took place it is fair to assume that if calcium powder in a sufficiently fine state of division were employed the reduction would take place readily in the cold, and if air were excluded and sufficiently large quantities of mixture employed, fused A1 could be obtained (see also Dr. Perkin, T. F , S., iii., 3, 184). In this reaction the A1 produced probably volatilised, and consequently oxidised under the very high temperature obtained, and this may account for the small percentage of A1 found and also for Dr. Perkin's failure to obtain globules of metallic Al. The authors intend repeating this experiment under such conditions as to avoid loss, &c.The presence of free A1 was shown by treating the finely powdered product with water until no more gas was evolved, even on heating, and then adding HCl ; a rapid effervescence of H took place, and A1 was found in the solution. The product contained about 8 per cent. of free Al. 2. Ca + MgO. The mixture, placed in a Hessian crucible, was found to react slowly when the surface was heated with a bunsen burner ; the surface Ca ignited, and the incandescence slowly spread throughout the mass from the top downwards. On cooling the contents of the crucible were found to be white at the top to a depth of about Q inch, and then of a deep yellow. It was thought at first the action was due to reaction of the Ca with the atmosphere forming a small amount of lime and a large amount of calcium nitride.That this was not so was evident from (I) the analysis of the resulting mixture ; (2) that the calcium when heated in a crucible by itself under the same conditions only burnt on the surface and remained unchanged below ; and (3) a mixture of CaO and Ca when treated in the same manner or even when strongly heated by a Bunsen flame only reacted at the surface. Analysis of the product gave- N as nitride = 5'79 per cent. Free Ca = 4-16 ,, ,, , j Mg = 0.58 9 , ,> It was not possible to decide whether the nitride was calcium nitride or magnesium nitride or a mixture of both, But from the large percentage of nitride (about 30 per cent. if calcium nitride) it appears that the atmospheric N plays a great part in the reaction observed. Series I I I .That Mg will readily reduce CaO in the cold is, of course, well known, this reaction serving for the preparation of argon from the air. A mixture made in the proportion Mg + CaO can easily be fired by a lighted I . Mg + CaO.CALCIUM, AND MAGNESIUM I33 match, the reaction proceeding steadily throughout the mass. product is of a bright yellow colour, and consists chiefly of calcium nitride. The resulting Analysis of product gave- Ca,N, = 33-65 per cent. Free Ca = 1'29 ,, ,, 9 , Mg = 0'47 9 , ,, In this reaction, in order to obtain a yield of Ca, air would have to be excluded. 2. 3 Mg + Also,. This mixture, in a Hessian crucible, easily reacted with a fuse ; the reaction was somewhat violent, the mass swelling up considerably.The resulting product was quite black. Analysis of product gave- N as nitride = 7'43 per cent. Free A1 = 0'71 ,, ,, ? J Mg = 3'87 > > I ? In this reaction, as in the case of Ca and A1,03, it is probable that most of the A1 liberated is converted into nitride and some re-oxidised to AI2O3. Although in these experiments, which were only carried out on a small scale (20 to 50 grams), complications arise partly from the interaction of the various hot metals with the air and with the oxides, it is quite evident that both Mg and Ca reduce Also3 in the cold and also that Mg easily reduces CaO with the formation of the free metal. It is thus evident that the heat of combustion of Mg is greater than that of Ca, since MgO is not reduced by Al, whilst CaO is at a very high temperature ; however, the heat of combustion of Mg is not much greater than that of Ca, since it is possible to cause Ca to interact with MgO ; also the heats of com- bustion of Mg and Ca are much higher than that of Al. The partial reductions of CaO by A1 and of MgO by Ca-probably endothermic reactions-are analogous to the reduction of B,03 by K and Na respectively. Gay-Lussac prepared B by heating B203 with K to a red heat in an iron tube. Now, the heat of combustion of B to B,O, is given as 317,200 (Troost and Hautefeuille-Watts, Dictionary), 3 14,821 by Roscoe and Schorlemner ; whilst the heat of combustion of K to K,O is given by Beketoff as 97,100 (L. and B.), 86,800 by Rengarde (7. C. S., Abs. TI., 156, 198), and 84,800 (i6id.). Hence B,03 + 6 K = 3 K,O + B, becomes thermally (using average values) - [ ( 3 1 6 ~ 0 ) -.. 3 (89,500)I a.e. = - 47,500 ; ie., heat must be supplied ; a similar reaction occurs with Na. CHEMICAL LABORATORY, THE POLYTECHNIC, REGENT STREET, W

ISSN:0014-7672    

DOI:10.1039/TF9080400130

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

T H E INFLUENCE O F CHEAP ELECTRICITY ON ELECTROLYTIC AND ELECTROTHERMAL INDUSTRIES. BY E. A. ASHCROFT, A.M.I.C.E., M.I.E.E., &c. ( A Pajer to be read before the Faraday Society.) The industries of electrometallurgy and electrochemistry became com- mercial only with the invention of the dynamo in 1867. And to-day we are standing on the verge of greater developments, fore- shadowed by the recent rapid increase in the production of such metals as aluminium and sodium in America and Europe, experiments in the electric smelting of iron, developments in steel refining, the success of the lime nitrogen works at Notodden, Norway ; the extensive growth of the carbide and, later, of the cyanamide industries in Norway, Italy, and Switzerland, the introduction of a successful lead-refining process, sulphide ore experiments, lead and copper smelting experiments, zinc distillation, and many other promising operations just emerging from the experimental stage.It is becoming clearer every year that the extent of these developments in the near future will depend on the limits to which the cost of electric energy can be reduced at suitable sites. For this reason the special influence of cheap energy on electrolytic and electrotherrnal industries, although not strictly a scientific question, becomes a matter of great interest to this Society. The large developments at Niagara Falls have familiarised the world with the possibilities of water-power ; but they have also brought certain well- defined limitations to light ; for it now becomes evident that at Niagara Falls the price of energy to the consumer is not low enough, and never can be low enough, to satisfy the rigid economical demands of many, technically possible, industrial processes which would soon become commercially possible with sufficiently cheap energy.But if Niagara power is too dear, what chances have the steam, gas, and oil engines’ motors which one hears so much about nowadays ? As main generators of energy for the purposes above stated, the answer is that they have no chance at all. For even if absolutely free and regular supplies of fuel were available for such engines (which is certainly not the case) the capital charges, and the upkeep would still bring the cost of the unit of electricity somewhere about the level of the Niagara prices, and still far above the “low-grade limit” which will be inexorably demanded by the coming new industries as a root condition of their being.I should be inclined to suggest for this “low-grade limit” about LGZ per kilowatt year (;GI 10s. per horse-power year) and we may at once quite safely assume that no means of producing energy at present known or thought of can touch this limit except one, and that I have designatcd water-power of Class I.” In some exceptional cases already the price of energy by water-power * That is to say, those water-powers in which favourable natural conditions enable the development of the power at a very low expenditure of capital, 1.34T H E INFLUENCE OF CHEAP ELECTRICITY, ETC. 135 ITEM. has been reduced below that limit.In fixing this limit I, of course, assume that some profit is to be made on the large industries considered as well as on the water-power, not merely the covering of working expenses and capital charges. STEAM ENGINES. ____ _--- -- -- , TABLE I. RELATIVE COSTS OF ELECTRICITY PRODUCED FROM STEAM, GAS, OIL, WATER (2) AND WATER (I) FOR CONTINUOUS LOADS. , & s. d. s. d. l - - 0 8 0 0 6 0 4 2 0 3 2 0 0 3 0 0 2 0 0 1 3 0 1 0 1 0 0 Fuel . . . . . . . . . . . . . . . . . . . . . Labour . . . . . . . . . . . . . . . . . . . . . Capital charges . . . . . . . . . . . . . . . Royalties on rights . . . . . . . . . . . . . . . Upkeep . . . . . . . . . . . . . . . . . . '':L s. d. ~ A s. d. 4 2 6 ' 3 3 0 O I I o ' o 8 o 0 1 3 o 1 0 1 0 0 3 0 0 2 8 6 I - - 8 6 6 1 6 9 6 1 GAS ENGIKES.1 OIL EXGINES. ITEM. 1 Per Kw. Year. Fuel . . . . . . . . . Labour . . . . . . . . . Upkeep . . . . . . Capital charges ... Royalties on rights ... +E s. d. 2 8 0 0 8 0 o 16 o 3 6 0 - I 6 1 8 o Per H.-P. Year. Per Kw. Year. Per H.-P. Year. I I _. :k;G s. d. I 14 o 0 6 0 2 13 6 0 I 2 0 - ' E S. d. 4 0 0 0 7 0 o 16 o 2 1 0 - 6 s. d. 3 0 0 0 5 0 0 I 2 0 I I 1 0 - * Varies greatly according to value of bye-products obtained. WATER, CLASS 11. ITEM. Per Kw. Year. Per H.-P. Year. Fuel . . . . . . . . . Labour . . . . . . Upkeep . . . . . . Capital charges ... Royalties on rights ... WATER, CLASS I. Per Kw. Year. 1 Per H -P. year. I A s. d. s. d. 0 8 0 0 6 0 0 1 3 0 , 0 I 0 0 - 070 I 0 4 0 0 I 0 0 2 0 0 1 I 1 0 0136 THE INFLUENCE OF CHEAP ELECTRICITY ON The undeveloped water-power of the world is still very large; and as a consequence no regular market value has yet been placed upon water rights in public estimation, (except in special circumstances where their market value is at once apparent).I have treated the possibilities of royalty payments as a contingent item in the comparison of costs. This item will, however, find its natural commercial level as industry extends, and the demand for such water-power increases. The accompanying Table I. of comparative costs of the various available meansof producing energyis prepared from manyrecords, and it aims at striking a useful average. Of course it follows without saying that no ‘‘ average price ” can be accurate for all countries, but nevertheless the difference in these figures in different situations is not in fact so great as might at first appear likely, when the division of water-powers into two classes is adopted.The principal difference is a fundamental and striking advantage peculiar to water powers of Class I. It is not proposed to discuss either steam, gas, or oil engines here, for a glance a t the table shows that they are quite out of court in this larger con- nection which we are considering. The best practical source of energy “in bulk ” to-day is the favourably- placed waterfall, and the second best is a waterfall of Class II., which may also sometimes have the advantage of being obtainable nearer home. A growing demand for large gas and oil motors, however, is indicated by the state of the markets to-day, a circumstance which is explained by the fact that many operations consuming energy are absolutely bound to be carried out at spots where no waterfall can be obtained.Moreover, in the particular industries which I am considering here quite a large demand may yet arise for gas and oil engines; for there are indications of a tendency to devise apparatus wherein a combined use is made of electrothermal (or electrolytic) and of direct combustion principles. Thus it has been suggested that a charge of iron ore, carbide materials, or similar raw materials, might be heated up by ordinary fuel combustion to nearly the required temperature and made thus to imbibe a large number of necessary heat units at a cheap rate, and then finished off by raising it to final temperature, with the aid of the more expensive electric heat.Such operations could, of course, be carried on economically at sites even nearer to the markets than the cheap water-power sites of which I shall speak presently, and an advantage of some importance might be thus obtained in respect of freights. Also, it is to be noted that in such countries as England and Germany, where there are few or no water-powers of Class I., there will be found a great desire to keep industrial operations as much as possible within the respective countries. For these reasons the gas engine has every chance of encouragement. But the fundamental, unalterable, natural economic conditions of any industry should not be wholly obscured by such considerations. I am convinced that much larger developments will take place during the next few decades at the first-class water-power sites.Such developments, in fact, are already taking place, and will be limited only by the comparative scarcity of this class of power in the world, and I may add by the false patriotic ideals which sometimes actuate the peoples of the few naturally favoured lands where such powers exist.::: * In Norway at the present time an absolutely unparalleled opportunity is offered to the country for a prosperous era of commercial development such as few countries have ever seen, but the people, though highly intelligent in other respects have not the power to appreciate it, in virtue of their national selfishness. Instead 0; rising as one man to meet this grcat opportunity, they are hampering the develop-ELECTROLYTIC & ELECTROTHERMAL INDUSTRIES 137 It is therefore probable that when such causes are removed there will be a reversal of the present exclusive policies, and then foreign capital will be welcomed, even subsidised and encouraged to develop the natural resources of the country.When this takes place I predict for these industries, and for that fortunate land which possesses the water-powers of such exceptional qualities, an immense access of prosperity. In support of this the following significant figures may be cited : Although electrically produced heat can probably never compete in cost, unit for unit, with heat produced from coal burned direct, yet the ratio of cost between the two is much lower than is usually supposed, whilst the ratio of efficiency brings the two still more nearly on a level, turning the balance in many cases in favour of greater economy for electric heating.One pound of an ordinary quality of coal will generate, if burned in a producer and supplied to a modern gas engine, about one electrical horse- power hour, and it will cost at the pit's mouth (at 8s. per ton) 'ogd. This amount of electric energy (one electrical horse-power hour) is equal to 644,544 gram calories of heat energy. Burned directly to generate heat, one pound of coal will produce approxi- mately 3,000,000 gram calories. Therefore by burning coal, for &I we may procure a theoretical combustion heat of approximately ~ ~ , o o o , o o ~ , o ~ ~ c a 1 or i e s . The same &I employed in purchasing electric energy at the cheapest rate (Class I., water) yields one electrical horse-power for 5,840 hours, and is therefore equivalent to 3,764,136,960 calories.This is just about one-quarter of the yield from direct combustion of an equivalent value of coal. I t may be assumed that the labour and wear and tear of the furnace will, taken together, be about equal in each case. The heat produced electrically can, however, be much more usefully employed, so that a true comparison of the cost of heating processes by the two methods can only be made in the full light of experimental data deter- mining the efficiency of each furnace or apparatus. When it is remembered that the efficiency of many non-electric furnaces is barely 10 per cent. of the theoretical and very few will exceed 25 per cent., whilst the efficiency of electric appliances sometimes reaches 75 per cent.and is often 50 per cent., it will be seen how closely this cheap power of to-day is competing with fuel combustion, even as a mere source of heat for metal- lurgical or chemical reductions. In the case of different water-powers a great deal of variability exists as to the possibilities of economy. The cost of labour and upkeep for a modern generating plant, actuated by water-power, with good machinery and untroubled by any irregularities of working may be easily reduced to a perfectly nominal sum (about 4s. per horse-power-year is sufficient in such cases for any fair-sized plant, and with very large plants it may be brought down to half that sum).The gross cost of the power to the consumer then becomes practically dependent on the amount of capital charges (and valuable private rights) involved. These items will vary enormously according to inent in every possible way by short-sighted anti-foreign legislation aimed especially at the exclusion of foreign capital-a policy which (like most selfish policies in the sphere of world-politics) a inore advanced order of intelligence would see hurts far inore the nation adopting it than it can ever hurt the foreign capitalist who has other fields for his energies to choose from if he is excluded from this one. It is my opinion, after studying this question a good deal from all sides? that short of carrying the waterfalls themselves out of the country (which, of course, is impossible), there is no possible way in which the free admission of foreign capital can do anything else than benefit Norway.138 THE INFLUENCE OF CHEAP ELECTRICITY ON whether the flow of water is naturally even all the year round, or whether expensive dams must be constructed to regulate it, whether the pipe is long or short, the fall high or low, whether much valuable property is submerged by damming, and other conditions.By designating the various water-powers Class I. and Class II., I distinguish in a rough, practical way between thosepowers where a high cost of regulation or of development has been necessary to bring the water to the place of con- sumption and to insure an even supply all the year round, on the one hand (Class II.), and those cases where these essential objects have been provided more or less completely by natural conditions (Class I.), thus rendering the total capital employed much lower.In general it may be stated that a capital expenditure of A7 0s. od. per e.h.p. capacity is sufficient for the development of powers of Class I., in- cluding all necessaries up to the dynamo terminals ; whilst some few powers which exist in Western Norway can be developed still more cheaply. On the other hand, water-powers have been developed in England and in other countries which have cost upwards of A60 0s. od. per electrical horse-power for harnessing equipment and compensations. The total equipment at Niagara Falls cannot have cost less than A30 0s. od. per horse-power in spite of the very large scale of operations.It is needless to say that unless it be undertaken for some very good and exceptional reason such an expenditure as A60 per horse-power in the light of our modern understanding of this subject is quite prohibitive and ought not to be seriously proposed. In considering the various water-powers available throughout the world there are, of course, many intermediate stages between these two extremes, and in some of these stages it may be possible to set some royalty value on the water rights. In general, however, it may be assumed that only powers which are strictly of Class I. will be able to successfully demand royalty values, and that powers of Class 11. (and intermediate stages) will only be developed in future when some public object is to be served by their employment.The grants for such powers will mostly be free, or nominal royalties only will be charged. The powers of Class I. (especially the best ones) are not very numerous, and their enormous natural advantages will to some extent be neutralised by the high prices which will naturally be placed on the water rights by owners, when their true values become known and when a ready market is opened for them. Nevertheless, I believe it is almost exclusively to powers of this type that we must look for the future of such gigantic possible developments as are suggested to-day by the looming processes of electrolytic iron, nitrate production, and the complete treatment of complex sulphide ores-three fields of enterprise, any one of which, if successfully developed, must rapidly exceed in magnitude the entire industry of electrometallurgy as it exists to-day.As this class of water-power seems destined to play so important a 7o"Ee in the near future, it will be of special interest here to give a concrete instance of such a water property and the method employed in Norway for arriving at the capitalised value of the water-right. The example is drawn from one of the most favourably situated of the many favourably placed of the small powers in western Norway, where the existence of these sources of energy on the verge of deep water and ice-free harbours suitable for any kind of shipping, is probably unique, offering advantages to industry found nowhere else in the world in such happy combinations.ELECTROLYTIC & ELECTROTHERMAL INDUSTRIES 139 The property was acquired about eight years ago from the former Norwegian owner.The purchaser left some mortgages standing, so that the capital stood as noted below when he succeeded in obtaining title (a royal concession under the Foreigners’ Exclusion Acts) to own the property. Extensive surveys had been made, the statistics of rainfall, &c., obtained, and the engineers had pronounced the waterfall (which had a fall of 1,000 feet, with a very short distance for tunnel and for pipe line from the outlet of the last lake to the lowest level) to be good for about 7,500 kw. (10,000 e.h.p.), and capable of development for less than -& (kr. 90) per h.-p., which sum was to include also some payments to farmers for fullest damming rights.It also included the cost of damming the principal lakes at a very favourable spot, whereby, for the comparatively small sum of -&,ooo, enough water could be stored in the large lakes to completely equalise the fall all the year round, and so use nearly every drop of water that falls on the watershed. Though the total area of the watershed was small, viz., about 40 square kilometres, the annual rainfall is the highest in Norway, reaching 3,600 mm. per year. There was therefore enough water to secure 3.8 cub. m. per second all the year round after liberal deductions for evaporation and loss. The lake basin was large enough to secure complete equalisation of the supply. Also the intervals of drought are never very protracted when compared with such periods in countries like England.All these circumstances are most favour- able for cheapest development. TABLE 11. SHOWING INFLUENCE OF THE COST OF DEVELOPING A SMALL WATERFALL WATER RIGHT AND FREEHOLD. SHOWING ALSO METHOD OF CALCU- LATING RETURN ON CAPITAL INVESTED. (AND INSTALLING MACHINERY) ON THE CAPITALISED VALUE OF THE The fall has a capacity of ca. 7,500 kw. It is supposed that a contract (with suitable guarantees) has been obtained for renting 6,000 kw. at an inclusive charge of A 2 10s. per kw. delivered at switchboard (= &I 17s. 6d. per e.h.p.). According to latest estimates and all existing contracts the expenditure required will be as follows, viz. :- Earthworks- A s. d. E s. d. Tunnel 300 m. long @ A4 8s. 3d. ... 1,323 5 0 . . . . .. . . . Intake, masonry, &c. 555 0 0 Pipe track levelling 555 0 0 Dam at Rorvik lake and cuts *.* 5,555 0 0 . . . . . . . . . . . . ... 7,988 5 0 -- (N.B., equal to &I 6s. 6d. per kw.) Buildings- One power station, two valve houses, sundry observation boxes, telephone posts, and sluiceman’s house 2,666 o o . . . . . . (N.B., equal to 9s. per kw.) Ironworks- One pipe line of 800 m. length with all sundries . . . . . . . . . . . . . . . 6,222 o o . . . . . . Sluices for dam, intake, and cuts 555 0 0 6,777 0 0 -- (N.B., equal to -&I 2s. 6d. per kw.) VOL. IV-T8140 T H E INFLUENCE OF CHEAP ELECTRICITY ON Mach in ery- Pelton wheel turbines, dynamos, and regulators . . . . . . . . . . . . . . . 12,777 o o Transformers and 2-kilo line . . . . . . 7,222 o o Electrical outfit .. . . . . . . . . . . 1,110 o o 21,109 0 0 -- (N.B., equal to A3 10s. per kw.) Special Charges and Allowaiaces- Extra compensation to farmers, payable on exercise of damming rights as per contracts . . . . . . . . . . . . . . . 2,220 o o Special tax demanded by Herredsstyrer 1,387 o o Contingencies on building estimates ... 2,277 o o Total development cost as estimated ... 44,424 5 o General margin for contingencies ... 5,555 o o 5,884 0 0 ---- (N.B., equal, say, to &I per kw.) 491979 5 0 -- This expenditure can be provided for by the issue of &33,333 preference shares and A16,665 by bank loan on mortgage or debentures. The water right can be paid for by the issue of A50,000 in ordinary or deferred shares. The complete scheme of capitalisation will then be as follows :- ;E s.d. A s. d. Existing mortgages . . . . . . . . . 13,888 o o Bank loans . . . . . . . . . . . . . . . 16,665 o o Preference shares, 8 per cent. . . . . . . 33,330 o o Ordinary shares to owners of water rights . . . . . . . . . . . . . . . 50,ooo o o --- 113,883 o o - The apportionment of revenue will be as follows :- Working Expenses- Wages, materials, taxes, and administra- tion . . . . . . . . . . . . . . . . . . Amortisation of plant and renewals- Buildings, 10 per cent. on &2,665 ... Ironworks, 5 per cent. on ;E13,000 ... Machinery, 5 per cent. on A13,888 ... Earthworks, 2+ per cent. on A8,ooo C q i t a l Charges. Mortgages- Interest at 5 per cent. on E13,888 ... Redemption fund 10 per cent. on ;G5,555 2+ per cent.on E8,332 . . . . . . . . . Bank loan- Interest 6 per cent. on ;G16,665 . . . . . . Redemption fund 5 per cent. on... ... The share capital- Preference shares ;G33,330 at 8 per cent. Ordinary shares &o,ooo at 8 per cent. ... 1,665 o o 267 o o 650 o o 694 0 0 200 0 0 3,476 0 0 --- 1,000 0 0 833 o o 1,833 0 0 --- 2,666 o o 4,000 o o -- - 6,666 o oELECTROLYTIC SE ELECTROTHERMAL INDUSTRIES 141 Revenue- 6,000 kw. sold at E2 10s. per kw. . . . . . . . . . . . . 15,000 o o --- Margin + 1,568 o o -~ This fall costs only A7 8s. per kw. to develop and equip. I t is therefore possible to place a considerable value on the water-rights. If the same revenue is obtained froin another waterfall (B) which, owing to less favourable natural conditions, will cost &8 5s.per kw. to develop and equip (an average cost in Western Norway), or from a third fall (C) costing AII 2s. per kw., then, omitting the ordinary shares altogether in the case of (C), and valuing the water-right at A25,ooo in ordinary shares in the case of (B), the account will stand as follows :- Total cost of development with B. margin in same proportion as s. d. . . . . . . . . . . . . before ..- 58,333 0 0 Schemes of Capitalisation- Existing mortgages before for the sake of comparison . . . . . . 13,888 o o Bank loans . . . . . . . . . . . . 22,220 o o Preference shares 8 per cent. ... 36,105 o o Ordinary shares for water right ... 25,000 o o Total capitalisation . . . . . . . . . Apportionment of revenue as follows :- Working Expenses- Wages, materials, taxes, and adminis- tration as before .. . . . . . . . Amortisation of plant . . . . . . . . . Capital Charges- Mortgages as before . . . . . . . . . Bank loans, 6 per cent. and 5 per cent. Preference shares, 8 per cent. ... Ordinary shares, 8 per cent. . . . . . . 1,665 o o 2,316 o o 1,488 o o 2,444 0 0 2,888 o 4 2,000 0 0 Revenue as before . . . . . . . . . 12,771 0 0 15,000 o o C. & s. d. 77,777 0 O 13,888 o o 27,775 0 0 49,995 0 O 91,658 o o - 1,665 0 0 3,088 o o 1,458 0 0 3,055 0 0 4,000 o o 13,266 o o 15,000 o o - ~~ Margin . . . . . . . . . . . . . . . 2,229 o o The &o,ooo ordinary shares in the case of Fall (A), and the &25,000 ordinary shares in the case of (B), and nothing (by comparison) in the case of (C), therefore represents the fair valuation of the water right, and when it is considered that the returns on these deferred shares rank after the preference shares and mortgages, and the revenue will gradually rise to 12 per cent. on all shares during the currency of the long contract by reason of the accumu- lation of the sinking funds for extinction of the loans, it must be allowed that the valuation is not excessive.There have been cases in Norway where the price of electric energy is said to be still lower than the figure I have selected as a probable minimum, * Without any dividend for ordinary shares.142 THE INFLUENCE OF CHEAP ELECTRICITY, ETC. viz., ;G2 10s. per kw. ; for instance, at Meraker, near Trondhjem, the power 3,000 h.p. has been sold at -&I 5s. 6d. per h.-p. on a seven years’ contract, and at Notodden I believe the price was &I 8s.for 3,000 e.h.p. It is not easy, in the absence of exact statements such as I have given above showing what allowances are set aside for interest on capital, sinking fund, &c., in stating such prices to make a comparison with the figures I have stated from my own experience. It may well be that when such investments become more popular lower returns on capital will be accepted, in which case the sale price may become proportionally lower without reducing the value of the water-right. For example, if for the development of the above-quoted waterfall supplies of capital could be obtained at a uniform rate of 5 per cent. (including interest and sinking funds), then, leaving all other items of expense the same (including depreciation on the works and plant), the price of the energy might be reduced to &z per kw. and the value of the water- right remain as above stated. It is by no means certain that there exist a very large number of powers which can be developed at even so low a cost as to permit of the sale of the energy at ;G2 per e.h.p. year (& 10s. per kw. year) either in Norway or anywhere else ; the value of such water rights may therefore very likely rise much above the value indicated by these estimates. For instance, if the current price of energy in the next few years finds a level at ;G3 per kw. year, the capitalised value of the undeveloped fall (A) in question would be about twice that shown in the table. It may be added that although the above valuation is self-evidently a just one, yet so little attention has been drawn to those remarkably favourable opportunities of producing cheap electrical energy with low capital expendi- ture and low working costs and under highly favourable conditions for its utilisation, that such values as those indicated by the above figures are not always attached to these properties as yet. How long this opportunity of reaping a large increment on capital combined with intelligence will remain open is a matter for the intelligent foreign capitalist and the Norwegian Government to decide between them. My belief that this subject has not received nearly enough attention, and that its great importance to the early expansion of electrolytic and electro- thermal industries, which it is this Society’s special mission to foster, has been somewhat overlooked, must be my excuse, if excuse is needed, for this special advocacy of a single class of motive power and for the simple nature and the purely commercial treatment of the subject chosen for this paper.

ISSN:0014-7672    

DOI:10.1039/TF9080400134

出版商:RSC    

年代:1908

数据来源: RSC