RlR. RITJSPRATT OX THE MUSPRATT,ESQ. Analysis of BEack-ash Soda-ash &. by FREDERIC -Conducting the operations in an estensive Soda Manufactory have repeatedly to investigate the several processes in all their intricate relations and more especially to malyse the numerous products in order to arrive at the necessary quantities of the different sulistances that should be employed in the mixtures for the production of a black-ash that would yield when lixiviated the largest amouint of subcarbonate Gf soda. the fabrication of soda as in all other technological processes correct data can only be arrived at by ascertaining exactly the composition of the products. Some of my results are completed and as they may prove interesting to the Society I transmit them through my brother Dr.Muspratt. The analysis of black-ash being somewhat complex my mode of procedure is appended as it may facilitate the progress of others embarking in a similar field of research. I dissolved a weighed portion of black-ash in aqua regia boiled and filtered the solution. 1. The residue was weighed 011 a dried filter. It consisted of charcod and sand. 2. I evaporated the filtrate and digested the residue with hydrochloric acid ; filtered again and determined the amount of silica which remained. 3. 'l'he solution was treated with ammonia to precipitate the phosphate of lime niid peroxide of iron which were ignited and weighed. ANALYSIS OF BLACK-ASH SODA-ASH &C. 4. I treated the filtrate from 3 with oxalate of ammonia precipitating the lime from the amount of which I calculated its compounds with sulphur and carbonic acid.5. The filtrate was evaporated with sulphuric acid to obtain sulphate of soda and sulphate of magnesia from which after deducting the magnesia determined in the usual manner by dissolving the compound and pre- cipitating with phosphate of soda and ammonia I obtained the soda; and after calculating the quautity that existed in cornhination determined the amount of caustic soda. hother portion of the ash was treated with concentrated nitric acid and the sulphuric acid precipitated by means of nitrate of baryta. Water was then added to another weighed quantity of black-ash till all the soluble portion was dissolved. The solution was then measured into three parts and the chloride of sodium sulphate of soda and d-phide of sodium were respectiyely determined.The amount of carbonic acid was ascertained with the aid of Will’s apparatus ; an aqueous solution gave in the first instance the carbonic acid combined with soda and secondly the black-ash treated with an excess of chromate of potash yielded the total quantity of carbonic acid. ANALYSIS OF BLACK-ASH. Calculated 011 100 parts without charcoal and sand. Carbonate of soda . 17*1Sl 18.804 Caustic soda* . . 7.970 SA723 Sulphate of soda . 1.500 1.642 Sulphide of sodium . 0.900 0.985 Chloride of sodium . 2.600 2.846 Sulphide of calcium . 25.048 28.509 Carbonate of lime . 17.045 18.655 Caustic lime . . 8.355 9‘144 Peroxide of iron.. *> 3.817 4.1 78 Phosphate of lime . silicate of magnesia . . 1.4130 1.620 . 4.472 4.894 Silicate of soda Charcoal and sand . . 7.942 -99*280 1OO-C)QO * Since this analysis was read to the Society a paper on the products of the Soda Manufacture by hlr. John Brown has appeared in the Philosophical Magazine for January 1849 in which the author objects to the manner in which Unger and Rkhztrdson have stated their results with regard to the carbonate and caustic Soda. Their determinations appear to me most satisfactory as tbey represent the value of the coinpound obtained in the process of manufacture in the same way that one mould state the richness of a metal procured in the manufacture of prmsiate of potash. Did the B2 MR.THORXTON JOI3X I-IERiPATH 0s THE The abore resiilts justify the assumption that a double salt of sulphide of calcium and lime is formed wliich is insoluble in water whereas the sulphide of calcium is soluble. The method employed in analgsing soda-ash was siniilar to t,hat described with reference to black-ash it will therefore be unnecessary to repeat it. AN,1T,TC;TS OF SODA-ASH. Calculated 011 LOO parts n-ithout charcoal and sand. Carbonate of soda . . 77-08;? 78.428 4,881 4-961 Caustic soda . Sulphate of soda . 3.110 5.198 Sulphide of sodium 0.630 0.640 Carbonate of lime . 0.320 0.525 Pcroside of iron . 0.324 0.329 Carbonate of potash . 0°200 0.204 Cyanide of sodium . 0.012 0.013 Silicate of soda . . 2*400 2.442 Chloride of sodium 7.130 7.256 Sulphide of calcium . 0.200 0-20-1 I Charcoal and sand . 0.G59 98.95 1 100~000 It will be seen from the above analysis that the quantity of caustic soda is very small proying that the carboiiates generally employed may be dispensed with as the access of air performs their office sufficiently for general purposes. I haye also had occasion to examine niaiip specimens of pyrites both before and after ignition and have invariably found the burnt pyrites to contain its sulphur in the form of sulphuric acid most probably in the state of a basic salt. The mass is perfectly insoluble in water.