Chlorine leaching of gold-bearing sulphide concentrate and its calcine

In view of the environmental limitation imposed on cyanide disposal, there is general interest in developing non-toxic, safe substitutes for cyanide in the gold leaching process. Chlorine leaching, as a potential alternative to the conventional cyanidation for the extraction of gold, was tested on a sulphide concentrate and its calcine from the Pearl River Area, South China. The basic feasibility of using the resin-in-leach (RIL) technique in chlorine leaching of the gold-bearing sulphide concentrate and its calcine is discussed. The experimental results showed that, under optimal leaching conditions, the extraction of gold can be over 96%. The effect of various parameters on the extraction and elution of gold was also studied. The absorption of gold was over 99% with a strong base anion exchange resin. Gold can be eluted easily from the loaded resin with acidic thiourea solution at ambient temperature. Based on the experimental results from bench tests, a flowsheet for gold recovery from the sulphide concentrate is proposed.