Silver leaching and recovery of valuable metals from magnetic tailings using chloride leaching

Abstract

Abstract To comprehensively reuse lead-zinc tailings, the recovery of valuable metals from magnetic tailings after iron recovery from lead-zinc tailings using roasting followed by chloride leaching was studied in this paper. The recovery of metals was investigated by studying the effects of roasting temperature, leaching temperature, liquid-to-solid ratio, chloride ion concentration and acid concentration on the metal leaching efficiency. The results showed that the leaching efficiencies of Ag, Ga and Pb reached 84.39%, 80.76% and 70.47%, respectively, at a roasting temperature of 900 °C and with the optimized leaching parameters. The Ag (9.98 mg/L), Ga (18.62 mg/L) and Pb (1506.12 mg/L) in the leaching liquor could be further recovered. The leaching kinetics showed that the silver leaching was controlled by the diffusion of the fluid species, and the activation energy was 22.06 kJ/mol. Furthermore, the leaching residue was analyzed. The results of X-ray fluorescence spectrometry, chemical speciation and extraction toxicity analyses suggested that the pollution risk of the leaching residue has been substantially eliminated and that further reuse of the residue was possible. With this method, the processes of metal recovery from magnetic tailings using roasting followed by chloride leaching were proposed for the comprehensive utilization of lead-zinc tailings.