Almalyk Mining and Metallurgical Plant, Almalyk, Uzbekistan:

A. S. Khasanov, Deputy Director of Science at the Science and Production Association, Professor, Doctor of Engineering Sciences, abdurashidsoli@mail.ru

Navoi State Mining Institute, Navoi, Uzbekistan:

B. I. Tolibov, Doctoral Student

In terms of the Kokpatas and Daugyztau deposits, the effect of preliminary calcination of goldcontaining flotation concentrates and industrial products, conducted prior to cyanidation, on gold recovery is studied. The material constitution of flotation concentrates and industrial products are studied, and the reasons of unsuccessful increase in gold extraction are shown: fine dissemination of gold in quartz; presence of iron-containing compounds in minerals; presence of minerals containing arsenic and iron sulfides, which play the role of reducing agents, absorbing oxygen during roasting and cyanides during leaching; carbonaceous substances. The behavior of arsenic during roasting is described, and the conditions of arsenic removal for the increase of gold extraction are proposed. The design of the furnace for roasting flotation concentrates and industrial products, which operates with a suspended layer of material, is proposed. This furnace design is also applicable to the fluidized bed of the material, in which all oxidation processes are carried out in an intensive mode. At the same time, the maintenance of the required furnace temperature is a significant factor, as exceeding a set index will cause the material to melt, thus making it difficult for the reagent to penetrate during cyanidation. Studies on biooxidation products carried out on a furnace with a suspended layer for oxidation of sulfur and carbon confirmed the results of the laboratory studies.

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