LLC “Gidrometallurgiya” Scientific and Research Center

Ya. M. Shneerson, Chief Executive Officer, Professor, e-mail: ims@gidrometall.ru

L. V. Chugaev, Leading Researcher

A. V. Markelov, Researcher

CJSC Gold-mining Company “Polyus”

M. T. Zhunusov, Head of a Science and Technology Department

S. V. Drozdov, Head of a Hydrometallurgy Laboratory of the Research Center

Bacterial oxidation is one of the most common methods of the revelation of hard gold concentrates. CJSC “Polyus” developed the Bionord^® technology — the technology of bacterial oxidation, which is used for many years. However, the bacterial method does not allow to oxidize the gold bearing sulphides completely. It is accompanied with obtaining of the considerable amounts of the elemental sulfur. It greatly increases the consumption of cyanide during the cyanidation process. A possible solution is to oxidize the elemental sulfur and residual amounts of the sulphide sulfur during the autoclave oxidation. This article presents the results of laboratory investigations in this direction. The object of research is the product of biooxidation, which contains 8.9% of elemental sulfur and 6.4% of sulphide sulfur. It is studied the influence of the process parameters (such as temperature and oxygen pressure) on the kinetics of autoclave oxidation of this material. It is shown that at the temperature of 225 ^оC and partial oxygen pressure of 0.5–0.7 MPa, the autoclave oxidation of the material can improve the gold recovery from 86% to 96% and decrease the cyanide consumption from several tens to 3–6 kg/t. The pilot tests of the process were held on the installation. This installation consists of 4 autoclaves, which are connected in serial. The capacity of each part is 12 liters. The results of the pilot plant tests confirm with the laboratory research. The gold recovery rate is not less than 96%, and cyanide consumption is not more than 5 kg/t. According to the results of this work, there is proposed the structural scheme of the industrial implementation of this process.

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