Mekhanobr Engineering JSC (Russia):

Bogdanovich A. V., Deputy Head of Department, Doctor of Engineering

Vasilyev A. M., Researcher, Ph. D. in Technical Sciences

E-mail (common): office@mekhanobr.spb.ru

Scientific and Research Centre «Gidrometallurgiya» (Russia):

Shneerson Ya. M., General Director, Doctor of Engineering

Pleshkov M. A., Leading Researcher, Ph. D. in Technical Sciences

The gold content of old tailings of the Urals copper and copper-zinc ore concentrating mills amounts to 1, and even 2 g/t. The article presents the results of a research project completed at Mekhanobr Engineering and Research Center «Hydrometallurgy» on a large representative sample of old flotation tails of one of the copper-zinc mills, in search for potential gold recovery flowsheets to pursue. Based on the outcome of the research work done the following promising flowsheets to extract gold from old tails were identified: direct cyanidation of the bulk of old tailings; separation of old tails in a spiral followed by cyanidation of the resultant concentrate; regrinding and cyanidation of the spiraled concentrate after copper extraction from the gravity concentrate by flotation. The most straightforward flowsheet ensuring sufficiently high gold recovery requires direct vat cyanidation of tailing feed reground to 80–90 % –0.044 mm. It also enables recovery of 34–40 % of gold for a cyanide consumption level of 2 kg/t of feed. It has been demonstrated that preliminary spiral separation of old tailings reduces the volume of feed for cyanidation and the consumption of cyanide almost by 50 %. However, it will decrease the total recovery of gold to 30–31 %. The flowsheet becomes even more complicated if it involves a flotation step, though it reduces the cyanide consumption by another 15–20 %. It is noteworthy that the final selection of a flowsheet for gold extraction from old pyritic tails requires careful economic assessment.

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