Selective arsenic-fixing roast of refractory gold concentrate

A novel pretreatment technique suitable for gold extraction from refractory ores was developed. The technique was based on selective arsenic fixing, u sing a fixing agent in the conventional two-stage roast. As in the existing fixing roast, more than 92 pet of the arsenic was retained in the calcine, using sulfate and lime as selective arsenic-fixing agents in fixing roast process. The arsenate retained in the leaching residue was found to be stab le. The selective fixing of arsenic allowed about 80 pet of the sulfur to b e recovered for sulfuric acid production. Compared to the existing fixing r oast, the amount of fixing agent added was reduced, accompanied by a reduct ion in solid-waste generation. Integrated in a two-stage roast under the op timal operating conditions identified, the new process resulted in a gold r ecovery of 89 to 91 pet from a typical refractory gold ore containing a sub stantial amount of pyrite, arsenopyrite, antimony, and carbonaceous and org anic carbons.