Gold extraction from a copper bearing ore by thiosulphate leaching.

Abstract

Gold extraction by cyanidation is reduced to less than 30% as the copper content in the ore is higher than 0 .3% Cu. Thiosulphate leaching process could overcome this problem. The effect of the variables on the gold extraction have been investigated. Under the optimun leaching conditions: 0 .4 M thiosulphate, 0.2 M ammonia, 0.03 M cupric ion and pH 11, 90% of gold was extracted. The possible processes for gold recovery from the pregnant solution was also discussed.