Abstract:Copper leaching rate of acid leaching-cyanide process in complex gold concentrate calcine acid leaching-cyanide process and leaching rates of gold and silver in subsequent cyanidation process were studied. The results show that leaching rates of gold, silver and copper are 93.21%, 83.25%, and 95.57% separately under the optimum leaching conditions including leaching temperature of 363 K, leaching time of 3 h, sulfuric acid concentration of 1.0 mol/L, stirring speed of 300 r/min, and L/S=4/1. Silicate inclusion is the main cause of low silver leaching rate. Content of silver silicate inclusions is 60.30% of total amount of silver in cyanide residue without additives in roasting process. Sodium hydroxide addition in roasting process can effectively reduce probability of silver silicate inclusion and improve silver leaching rate. Content of silver silicate inclusion is only 27.56% of total amount of silver in cyanide residue in sodium hydroxide roasting process.