JSC URALINTEKH (Yekaterinburg, Russia)
I. Е. Rudakov, Engineer of the Laboratory of Hydrometallurgical Processes
P. S. Potapov, H ead of the Laboratory of Hydrometallurgical Processes, p.potapov@pm-ural.com
А. О. Chugunov, Laboratory Engineer
А. V. Еrmakov, General Director, aleksander.ermakov@pm-ural.com
Ural Federal University named after the First President of Russia B. N. Yeltsin (Yekaterinburg, Russia)
V. G. Lobanov, Associate Professor of the Department of Metallurgy of Non-Ferrous Metals, Candidate of Technical Sciences, v.g.lobanov@urfu.ru
During the processing of platinum-group metal concentrates (Oku grade) at the refining facility of JSC Uralintekh, a significant amount of impurity nonferrous metals, primarily copper, accumulates in recycled process products. The presence of copper in cementation precipitates formed after deep depletion of pregnant solutions necessitates additional reagent consumption and significantly complicates subsequent processing operations. The removal of copper from the process cycle is therefore an important task from both technological and economic perspectives. Known methods for the selective extraction of copper from polymetallic raw materials have been analyzed. Taking into account the phase composition of the cementation precipitate and the need to completely retain precious metals in the insoluble residue, a sulfate system based on Fe2(SO4)3 – H2SO4 has been selected as the preferred option. Studies have been conducted with the primary objective of optimizing the conditions for selective leaching of copper from a cementation precipitate containing platinum-group metals, gold, and silver. A regression equation for the process has been obtained using the method of mathematical design of experiments. Verification has confirmed the statistical significance of the resulting model. The optimal conditions have been established as follows: CFe2(SO4)3 = 0.96 M, CH2SO4 = 0.12 M, temperature = 63 °C, leaching time = 2 h, and liquid-to-solid ratio (L:S) = 4:1. Copper recovery of up to 95% has been achieved, with no transfer of precious metals into the solution.
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