Research On Process For Hydrometallurgical Extraction Of Sb And Au From An Antimony-Gold Concentrate

Abstract:Aiming at the problems of complicated process, high energy consumption, serious environmental pollution and low recovery of precious and base metal, a wet process of extracting antimony and gold from an antimony-gold concentrate is researched in this paper.Test on leaching of antimony from the antimony-gold concentrate which contain antimony of24.76%and gold of48.50g/t, the results showed that the gold loss rate was16.72%under the optimum conditions of antimony leaching with sodium sulfide, the separation effect is not thoroughly, and the method is infeasible. The optimum operation conditions of antimony acid leaching are obtained as that the temperature is95℃, HCl concentration is4.0mol/L, liquid-solid rate is4:1, FeCl3excess coefficient is1.1, leaching time is0.5h and agitation rate of100rpm. On these conditions, antimony content was0.54%and gold was106.66g/t, the leaching rate of antimony reached99.05%while that of gold was only0.99%, which means high leaching rate of antimony, low loss of gold and the excellent separation are achieved. Above all, it established the foundation for favorable selective leaching of antimony and gold.Research on the property and pretreatment of antimony leaching residue showed that because of pretreatment of antimony by desulfurization with heated sodium hydroxide-chemical oxidation have many problems, such as complicated process, high loss rate of gold and reagent cost, oxidizing roasting was chosen as the best pretreatment process of antimony. The oxidation roasting conditions are roasting temperature of600℃, roasting time of1h, the results showed that the sulfur content of calcine was0.15%, the desulfurization rate was99.84%, and the main phase were hematite and gangue minerals. Changes of chemical composition and phase in the process of oxidizing roasting are studied by XRD and chemical phase analysis, reveal the mechanism of oxidizing roasting. The result showed that elemental sulfur is oxidized firstly, followed by decomposition and oxidation of pyrite, and the wrapped gold are gradually released with pyrite are destroyed, which also proved included-gold with pyrite is the main reason of difficult leaching of gold. Parameter optimization of the process of gold leaching, studies showed that the highest gold leaching rate reached95.92%with the leaching time of48h and NaCN concentration of0.3%.Integrated the whole teat process, the process of acid leaching of antimony-oxidizing roasting-cyanide leaching of gold is recommended, it realized the separation and recycling of antimony, sulfur and gold. Finally, the high leaching rate of antimony and gold are achieved.