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

Research presented in this article was carried out in order to develop a technology for processing low-grade copper-zinc sulfide concentrates. At the stage of laboratory testing, the influence of key parameters (residence time, acidity, concentration of copper and zinc in solution) of hydrothermal alteration (HTA) on process performance (extraction of copper and zinc) was determined. The features of the medium-temperature hydrothermal alteration process of copper-zinc concentrates are noted. It has been established that the transition of zinc and iron into the leaching solution is stimulated by partial oxidation of the material at the beginning of HTA. It is noted that an increase in the concentration of copper in the solution allow to increase zinc recovery to the solution. It was found that the process of zinc reprecipitation may occur under low copper concentration and extended time of HTA process. The results obtained on the laboratory stage were confirmed during pilot plant tests, during which various HTA 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 are 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 Zinc Plant (Balkhash, Kazakhstan). New scheme on 80% is equipped with existing equipment of the Zinc Plant.

1. Naboychenko S. S., Ni L. P., Shneerson Ya. M., Chugaev L. V. Autoclave hydrometallurgy of non-ferrous metals. Ekaterinburg : USTU – UPI, 2002. 940 p.
2. Habashi F. Recent trends in extractive metallurgy. Journal of Mining and Metallurgy. 2009. Vol. 45B, No. 1. pp. 1–13.
3. Dreisinger D. Case study flowsheets: Copper-gold concentrate treatment. Developments in Mineral Processing. 2005. Vol. 15. pp. 825–848.
4. Shneerson Ya. M., Naboychenko S. S. Trends in the development of autoclave hydrometallurgy of non-ferrous metals. Tsvetnye Metally. 2011. No. 3. pp. 15–20.
5. Pinigin V. K., Naboychenko S. S., Khudyakov I. F. Zinc removal from copper-zinc products by sulfuric acid solutions in autoclave. Tsvetnye Metally. 1973. No. 10. pp. 23–24.
6. Shneerson Ya. M., Ivanova N. F. Application of autoclave methods for removal of impurities from refractory copper polymetallic concentrates. Tsvetnye Metally. 2003. No. 7. pp. 63–67.
7. Boduen A. Ya., Ivanov B. S., Ukraintsev I. V. Copper concentration from sulfide ore: state-of-the art and prospects. Non-ferrous Metals. 2015. No. 1. pp. 17–20.
8. Weidenbach M., Dunn G., Teo Y. Y. Removal of impurities from copper sulfide mineral concentrates. Proceedings of 7^th Annual Nickel-Cobalt-Copper Conference ALTA 2016. Perth, Australia, 21–28 May 2016. pp. 335–351.
9. Vinals J., Fuentes G., Hernandez M. C., Herreros O. Transformation of sphalerite particles into copper sulfide particles by hydrothermal treatment with Cu (II) ions. Hydrometallurgy. 2004. Vol. 75. pp. 177–187.
10. Sadykov S. B. Autoclave processing of low-grade zinc concentrates. Ekaterinburg : UrO RAN, 2006. 582 p.
11. Оspanov E. А., Shakhalov А. А., Shneerson Ya. M., Fomenko I. V. Autoclave technology for treatment of polymetallic concentrates in oxidative-reduction conditions. Proceedings of the scientific and practical conference “Intensification of hydrometallurgical processes of recycling of natural and technogenic raw materials. Technologies and Equipment”. Saint-Petersburg, 2018. pp. 135–138.
12. Lyakh S. I., Klementev M. V., Shneerson Ya. M. Autoclave pilot plant for conducting semi-industrial tests of the oxidation of sulfide flotation concentrates of gold-bearing ores. Non-Ferrous Metals – 2012 : Materials of the Fourth International Congress. Krasnoyarsk, 2012. pp. 584–589.