Study of gold and silver leaching processes from sulfide ores

Abstract

Precious metals are mainly recovered from rebellious gold-bearing raw materials through use of sodium cyanide alkali solutions. Reduced cyanide solutions consumption providing high leaching efficiency are the most challenging problems we face today in precious metals hydrometallurgy. We thoroughly studied processes of precious metals leaching with mixed cyanide-thiosulfate solutions as compared to the individual cyanide and thiosulfate solutions at equal concentrations and experimental conditions. Silver and gold-bearing sulfide ore (deposit in Kazakhstan) composed as follows, %: 2,8 g/t Au; 68,8 g/t Аg; 0,36 Cu; 0,09 Zn; 0,03 Co; 0,06 Ni; 13,8 Fe; 0,30 Mn; 6,4 Stotal; 0,1 As, was selected as a subject of our research. It was shown that the silver recovery degree where mixed solution was used amounted 61,1%, while in processing with individual cyanide and thiosulfate solutions this value was equal to 40,8% and 49,5%, respectively.