No abstract available

[en] The solvent extraction of molybdenum(VI) from sulphuric acid solutions with di-(2-ethylhexyl)-phosphoric acid (HDEHP) and monododecylphosphoric acid (HDDP) in n-heptane has been studied (a) as a function of the concentration of sulphuric acid, molybdenum and the extractant; (b) in the presence of copper and zinc in the aqueous phase and (c) in the presence of tri-n-butylphosphate (TBP) in the organic phase. The distribution of the sulphuric acid between aqueous and organic phase has also been studied. The results obtained fail to provide evidence on whether extraction of sulphate complexes of molybdenum is possible in the system studied because of the lack of correlation between the extraction of molybdenum and of sulphuric acid, and the occurrence of the competition. It seems likely that from concentrated solutions of sulphuric acid molybdenum is extracted in the form of molybdenic acid associates. (T.G.)

[en] The selective separation of Cu, Zn, and Mn from various liquid secondary raw materials has been studied by means of radionuclides. The establishment of equilibrium in a mixer-settler could be continuously followed. The suitability of various industrial extractants such as LIX 64 N, Acorga P-17, Kelex 100, D 2 EH PA for the extraction of those nonferrous metals from spent zinc electrolytes and from solutions obtained by leaching Cu/Zn scrap has been determined on the basis of a new selectivity criterion. Good results have been achieved by selecting the optimum extraction and reextraction conditions. (author)

No abstract available

[en] The principles are presented of the radioisotope tracer methods applied to the study of efficiency and kinetics of hydrometallurgic processes of leaching and liquid extraction and also to the study of the hydrodynamics of hydrometallurgic apparatus. These methods were applied in the investigations of the hydrometallurgical processing of materials from the copper industry and to the hydrodynamics of various types of leaching apparatus and of a bath for copper electrorefining. (author)

No abstract available

[en] The use of radioisotopes in investigating hydrodynamic processes in multiphase hydrometallurgy is described. The extraction of copper from copper concentrates with the aid of a ferrous sulfate solution, the desilification of sodium aluminate (in producing Al₂O₃ according to the Grzymek method), and the corresponding equipment have been investigated. Further investigations covered the hydrodynamics of the solid phase in a multistage apparatus for continuous hydrolysis of alkaline aluminium-ammonium sulfate (in producing Al₂O₃.7 H₂O). Furthermore, some laboratory investigations of the copper extraction from waste material by means of liquid-liquid extraction are described. (author)