Kazakhstan Academy of Natural Sciences, Almaty, Kazakhstan:

N. S. Bekturganov, First Vice-President

Institute of Metallurgy and Ore Benefication, Almaty, Kazakhstan:
G. A. Arystanova, Senior Researcher
A. K. Koyzhanova, Leading Researcher, e-mail: aigul_koizhan@mail.ru
M. B. Erdenova, Leading Engineer

This paper shows the results of the comparative study of efficiency of methods of gold extraction from anthropogenic flotation tails by gravity concentration, agitation cyanidation and biooxidation with following leaching. We investigated the chemical and mineral compositions of flotation tails using spectral, semi-quantitative, chemical and mineralogical analysis. The investigated sample of anthropogenic flotation tails is poor raw material, containing 0.6 g/t of gold. The basic goldconnected sulfur-containing minerals are arsenopyrite (5.97%) and pyrite (4.2%). Gold grains are found in quartz and sulfides in irregular isothermal form and in fine-disperse state. The process of gravity concentration of flotation tails was investigated. Its low efficiency is shown – gold extraction in gravity concentrate is not more than 14.2%. 57.8% of gold is extracted by cyanidation. Increasing of gold extraction, included in sulfides and pyrite, recommends the use of bacterial oxidation of flotation tails using acidophile bacteria At. Ferrooxidans, preliminary adapted to the substantial composition of investigated sample, followed by sodium hypochlorite solution treatment and cyanidation. Combination of processes of preliminary sulfuric acid washing of flotation tails, bacterial leaching using acidophile cultures Acidithiobacillus ferrooxidans, hypochlorite treatment of biooxidation and cyanidation cake provide high gold extraction (75%) from flotation tails and its content 0.6 g/t.

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