Abstract:Cyanide residue produced by gold industry has been listed as solid hazardous waste, and its detoxification treatment technology is a serious challenge that all gold enterprises have to face and a major problem that must be solved as soon as possible. The technical feasibility of treating low grade cyanide residue with low temperature micro-melting process and efficiently recovering precious metals and valuable metals were studied. Effects of roasting temperature, roasting time and dosage of additives on recovery of precious metals were investigated. Under the condition of existing of accelerant, low temperature and reducing atmosphere, formation of valuable metal matte (such as Au, Ag, Cu, Pb and Zn mattes, etc.) with low melting point, matte nucleus growth and mineralization were illustrated. The mechanism of flotation of quenching matte was also clarified. Under the optimized conditions, the cyanide tailings (Au 1.71 g/t, Ag 54 g/t and Fe 32.71%) were treated. Gold grade in final residue could be reduced to 0.14 g/t, the grade of gold and silver in flotation concentrate is 35.46 and 737.14 g/t, respectively, and the average recovery of gold and silver is 92.44% and 80.67%, respectively. The grade of iron in iron concentrate obtained by magnetic separation is 63.57% with 83% recovery rate and 68% yield. This process can effectively recover precious metals and realize the harmless disposal and resource utilization of low-grade cyanide residue.