A review of the selective leaching of gold from oxidised copper–gold ores with ammonia–cyanide and new insights for plant control and operation

Abstract The ammonia–cyanide leach system was first patented over 100 years ago and stands out as a unique method of selectively leaching up to 90% Au and This paper reviews some of the recent applied and fundamental studies on the leaching of copper–gold ores with the ammonia–cyanide system and provides insights into the mechanism to give a better appreciation of the key parameters required for the optimum leaching of gold with minimum copper dissolution. Recommended leach compositions, Eh and pH are provided to enable process control measures to be adopted for a variety of ores. The selective recovery of gold from the leach solutions by cementation or adsorption onto activated carbon or ion-exchange resins is also discussed.