Biooxidation-cyanidation leaching of gold concentrates with different arsenic types

The biooxidation and cyanidation leaching of gold concentrates and monominerals with different arsenic types were studied.The effects of arsenopyrite and realgar on the biooxidation and cyanidation leaching of gold concentrate were investigated.The results show that arsenopyrite in the arsenic-bearing gold concentrate is easily oxidized and decomposed.The dearsenification rate rises up to 93.10% after 192 h biooxidation.On the contrary,realgar cannot be biooxidated,which restrains the growth of bacteria and extends the lag phase.In the process of cyanidation leaching,arsenopyrite is very stable and does not participate in any side reactions,conversely,realgar participates in the side reactions with cyanide and alkali.The efficiency of cyanidation leaching is depressed because the precipitates produced form the film on the surface of gold grain in the process of cyanidation leaching.