METHOD FOR EXTRACTING GOLD FROM CONCENTRATES Russian patent published in 2014 - IPC C22B11/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy of non-ferrous and precious metals, and namely to removal of gold from concentrates. The method involves stage-by-stage cyanide leaching of gold, at the first one of which the crushed raw material is leached at stirring by a return cyanide solution. A sand fraction is extracted from the product of the first stage by classification. At the second stage, the sand fraction is leached out in the cyanide solution with NaCN concentration of 0.5-2 g/l. With that, solutions obtained at the second stage are directed for leaching of the raw material. Gold is extracted from leaching solutions of the first stage. Leaching cakes of the first and the second stages are mixed with binding agents and porous filler; the mixture is granulated, stocked in the form of a pile, and additionally, gold is removed from the pile by heap leaching. As porous filler, bituminous coal combustion ash is used in the amount of 5-10% of weight of cakes. Heap leaching of gold is performed by an ash-free solution with NaCN content of 0.1-0.5 g/l. The product solution of heap leaching is strengthened with cyanide and directed to a leaching stage of the sand fraction.

EFFECT: improving total extraction of gold from concentrates by 4-5%.

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