JSC “Chelyabinsk Zinc Plant”, Chelyabinsk, Russia:

Yu. V. Reshetnikov, Deputy Technical Director — Production Control Manager, e-mail: uvr@zinc.ru
O. V. Belyakov, Head of Hydrometallurgical Shop
K. M. Kozlov, Deputy Manufacturing Head of Hydrometallurgical Shop
M. S. Varganov, Production Engineer of Engineering Center

Since 2010, Chelyabinsk Zinc Plant has been using a comprehensive technology of zinc, cadmium, and indium extraction from oxidized material, including such methods as Waelz-process, off-gas calcination in large pipe furnace and leaching of calcined products with extraction of zinc, cadmium and indium into solution and lead extraction into lead concentrate. This article provides a currently approved three-stage scheme of hydrometallurgical processing of calcined Waelz-oxide, optimal technological parameters of the process conducting under these conditions, raw material composition for processing and composition of obtained lead concentrate. Results of development of adopted technology of hydrometallurgical processing of calcined Waelz-oxide are shown. In comparison with processing of un-calcined Waelz-oxide (with previous washing from Cl and F), this technology allowed to carry out the following measures:
– 33–36% productivity increase of hydrometallurgical plant leaching department because of material bulk density growth (from 0.92 to 2.0 tones/m³);
– reduction of zinc and cadmium losses with lead cake by 2.7% and 4.6% respectively because of increase of zinc dissolution (by 3.8%) and cadmium dissolution (by 35.3%);
– reduction of impurities content in zinc sulfate solution, namely: arsenic - by 70%, chlorine — by 41%, and fluorine — by 7%;
– reduction of wastewater volume, requiring treatment and utilization by 90.5%.

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