National Research Tomsk State University, Tomsk, Russia:

V. I. Sachkov, Associate Professor, Head of the Chemical Technology Laboratory, Doctor of Chemical Sciences
R. A. Nefedov, Senior Researcher, Candidate of Chemical Sciences
P. S. Shcherbakov, Junior Researcher, e-mail: xcrbgc@gmail.com
D. I. Leonov, Junior Researcher

This paper examines the processing behaviour of gold-bearing carbonaceous shales sampled from the Kirovsk-Kryklinsk ore-bearing zone and describes a feasibility study that proposes to use the method of heap leaching and some synthetic materials. The authors looked at the material composition, as well as physical, hydrophysical and physicomechanical properties of the above ore. It was established that the gold identified in the sample is partially found in the form of gold nuggets. The preg-robbing activity, shale content and pelletization parameters of the ore were determined. Agitation and percolation leaching with sodium cyanide was used to extract gold from primary ore. A sequential pretreatment of slurry with synthetic materials (formaldehyde solution and polyvinyl alcohol) before agitation cyanidation results in a 205 or 293% increase in the recovery of gold into liquor depending on the pretreatment method. The maximum gold recovery reached during agitation leaching was 76.51%. The residual concentration of gold in the ore was 1.17 g/t. It was found that the pretreatment of ore before cyanide leaching helps to considerably lower the preg-robbing activity of the studied ore in relation to gold. The paper proposes to use synthetic materials for ore pelletization for the purposes of percolation leaching. After such pretreatment the gold recovery during percolation reaches 56.82% (compared with 20.91% without pretreatment), with the residual concentration of gold being 0.95 g/t ore. The phase and elemental analysis of ore sampled from the Kirovsk-Kryklinsk ore-bearing zone revealed the presence of an indium-bearing phase, which suggests that the said ore may contain trace elements.
Contributors to this paper include A. S. Sachkova, Candidate of Biological Sciences; junior researcher R. O. Medvedev, junior researcher I. Amelichkin, postgraduate student O. V. Nefedova, engineer V. S. Soloviev, laboratory assistant D. A. Biryukov.
This research was funded by the Ministry of Education and Science of the Russian Federation under Governmental Assignment No. FSWM-2020-0028 and under the Tomsk State University Development Programme Priority-2030.

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