JSC “Irgiredmet”, Irkutsk, Russia:

A. V. Boldyrev, Junior Researcher (Laboratory of Metallurgy), e-mail: durazell@rambler.ru
S. V. Balikov, Chief Researcher of Laboratory of Metallurgy
A. V. Bogorodskiy, Senior Researcher of Laboratory of Metallurgy
Yu. E. Emelyanov, Leading Researcher of Laboratory of Metallurgy

In recent years, gold mining industry has faced with significant changes in precious metals recovery from refractory ore or technogenic raw materials by direct cyanidation. These refractory ores include gold-pyrite and gold-arsenic ores and their concentrates, containing refractory gold. Their reserves make up a significant proportion, according to which, new prospective projects are constantly developed. This paper gives the results of POX of refractory gold-bearing concentrates using halide-ion as solvent for precious metals and activated carbon as adsorbent. It was found that gold did not recover to the solution when halide was added during POX. Silver was partially dissolved in the solution. When halogen-containing reagents and activated carbon were added during POX, gold was dissolved and loaded into the activated carbon. Sulfide oxidation degree was 99.3–99.6%. Gold recovery into granulated carbon was 94.7–94.8%, using chlorine-bearing solvents (NaCl, CaCl₂ and carnalite); and 98–99% — using KI and KBr. This treatment process of refractory gold-bearing concentrates combines sulfide oxidation, dissolution and adsorption of precious metals. Metal recovery results obtained during this process can be compared with the recovery during POX-cyanidation. In this case, sodium cyanide is not used. This allows the reduction of capital and operational costs due to the absence of cyanidation, carbon-in-leach and detoxification of leaching tailing circuits.

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