Kazakhmys Corporation LLP, Almaty, Kazakhstan:

A. A. Shakhalov, Project Manager of Department of Complex Processing of Technogenic Raw Materials, e-mail: aleksandr.shahalov@kazakhmys.kz
E. A. Ospanov, Head of Department of Complex Processing of Technogenic Raw Materials

Ural Federal University named after the first President of Russia B. N. Eltsin, Ekaterinburg, Russia:
S. S. Naboychenko, Visiting Professor of a Chair of Metallurgy of Heavy Non-Ferrous Metals

LLC “Scientific-Research Center “Gidrometallurgiya”, Saint-Petersburg, Russia:
I. V. Fomenko, Research Director

Researches presented in this article was carried out with the aim to develop a technology for processing substandard copper-zinc sulphide concentrates. At the stage of laboratory batch testing the influence of key parameters (residence time, acidity, concentration of copper and zinc in solution) on the parameters of the leaching process (extraction of copper and zinc) was determined. Features of medium temperature pressure oxidative leaching of sulfide concentrates are noted. Particular attention was paid to the formation of elemental sulfur in the process of autoclave leaching. It is noted that an increase in the concentration of copper in the solution allow to accelerate the oxidation process and to decrease the content of elemental sulfur in the oxidized residue. Concentration of sulfuric acid, on the contrary, has a strong inhibitory effect and promote the increase of amount of elemental sulfur. The results obtained on the laboratory stage were confirmed during pilot plant tests during which various leaching regimes were tested in a continuously operating autoclave. The main objective of the pilot tests was the final selection of the optimal mode of the pressure oxidation process, as well as obtaining the indicators which is necessary for further process design. Developed technology includes two pressure leaching steps with subsequent flotation enrichment of pressure leaching residues with extraction of copper, zinc and lead into separate products. Obtained products will be subjected for further processing or for sale. Process diagram for processing substandard concentrates was developed on a base of Balkhash zinc plant (Kazakhstan). New scheme on 80% is equipped with existing equipment of the Balkhash zinc plant.

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