摘要:

AbstractResults are presented which indicate the effect of pH and flotation‐collector type upon the flotation rates of natural rutile particles. Above pH ∼2.5, flotation rate decreases with increasing pH for anionic collectors and increases with increasing pH for a cationic collector. These results are in agreement with expectations from the known electrokinetic properties of the mineral. Also, for a fixed pH, the rate of flotation is influenced by the length of the carbon chain associated with the collecting ion, and, for any one collector, by its concentration in solution. Below pH ∼2.5, the flotation rate with anionic collectors decreases with fall in pH, whereas with the cationic type a small increase in rate is shown as pH1 is appro

ISSN:0021-8871    

DOI:10.1002/jctb.5010160601

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractStudies of the reaction between hydrazine and oxygen at 25° and 70° in alkaline solution have shown that the observed rate is due to catalysis by traces of impurities. It has been found that copper(II) and manganese (II) are the most active catalysts, and, under certain conditions, the copper(II)‐catalysed reaction appears to be homogeneous. Evidence is presented that catalysis occurs by redox reactions. The copper(II)‐catalysed reaction has been studied in some detail, but only the earlier stages fit a simple kinetic equ

ISSN:0021-8871    

DOI:10.1002/jctb.5010160602

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractA hydrocarbon‐soluble vanadium‐activated system consisting essentially of vanadyl di‐isopropylsalicylate and phenylcyclohexane hydroperoxide proved to be an active initiation system for the low‐temperature emulsion copolymerisation of butadiene and styrene. Mercaptans were observed to have a promoting as well as a modifying effect in this system. Whereas complete omission of the mercaptan resulted in a very low conversion, high conversions were obtained with as little as 0‐01 g per 100 g of monomer. No initiation took place when the polymerisation was carried out in a homogeneous phase, e.g. i

ISSN:0021-8871    

DOI:10.1002/jctb.5010160603

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractLead dioxide is the active constituent of the positive electrode in the lead‐acid battery. Both the α‐ and the β‐modifications are present in battery electrodes andX‐ray diffraction techniques must be used to differentiate the role of each in the reactions occurring in the lead‐acid battery system. Standard samples of the two forms of lead dioxide are necessary for this purpose, and samples prepared by various methods have been studied. Powder patterns of electrodeposited samples of both α‐ and β‐lead dioxide showed preferred orientation effects which could not be removed by grinding. Chemically prepared samples of the two forms were well crystallised and did not produce preferred orientation effects. α‐Lead dioxide prepared by the oxidation of yellow lead monoxide (using a fused mixture of sodium chlorate and sodium nitrate) and β‐lead dioxide prepared by hydrolysis of lead tetra‐acetate were chosen as standard samples forX‐ray studies and their diffraction patterns have been recorded. A mechanism of nucleation has been proposed for the formation of α‐lead dioxide in alkaline and neutral media

ISSN:0021-8871    

DOI:10.1002/jctb.5010160604

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractA brief review is presented of the classification of methods of separation and of the selection of the best method.

ISSN:0021-8871    

DOI:10.1002/jctb.5010160605

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractUranium dioxide of high purity has been precipitated directly from acid uranyl nitrate solutions by hydrogen in a stainless steel autoclave at temperatures in the region of 300° and pressures up to 40 atmospheres. The thermodynamics of the reaction are discussed

ISSN:0021-8871    

DOI:10.1002/jctb.5010160606

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractA selective sorption of uranyl ions on organic ion‐exchangers containing ‐OPO(OH)2or ‐PO(OH)2groups from dilute nitric acid solution and the affinity of various divalent cations to these groups in acetate medium were studied. Practical applications of these ion exchangers for the separation are desc

ISSN:0021-8871    

DOI:10.1002/jctb.5010160607

出版商:John Wiley&Sons, Ltd    

年代:1966

数据来源: WILEY