EXTRACTION METHOD OF GOLD FROM OXIDISED ARGILLACEOUS GOLD-BEARING ORES Russian patent published in 2011 - IPC C22B11/08 

FIELD: metallurgy.

SUBSTANCE: extraction method of gold from oxidised argillaceous gold-bearing ores involves grinding, sieving of ore, mixing of ore with binding substance, pelletising of ore so that pellets are obtained, formation of stock pile from the obtained pellets and heap leaching of gold by spraying of sodium cyanide solution so that solutions enriched as to gold are obtained. As binding agent there used is product of mixed grinding of the mixture containing 70% of blast-furnace granulated slag and 30% of lime in terms of active CaO taken in quantity of 25 kilograms per ton of ore. Prior to spraying of the stock pile, it is exposed for five days. Fragmentation size of ore is 60 mm; at that, product of mixed grinding of the mixture consisting of blast-furnace granulated slag and lime has grinding fineness corresponding to specific surface of 3000-3500 cm²/g. Height of stock pile is not more than 15 metres, and as leaching solution there used is solution with cyanide concentration of not more than 0.5 g/l.

EFFECT: increasing the extraction degree of gold to commercial output at simultaneous reduction of duration of leaching process and its cheapening.

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