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

• Published in: Journal of cleaner production 2018-04, Vol.181, p.408-415
• Main Authors: Lei, Chang, Yan, Bo, Chen, Tao, Wang, Xiao-Liang, Xiao, Xian-Ming
• Format: Article
• Language: English
• Subjects: Chloride leaching; Leaching residue; Lead-zinc tailings; Metal recovery; Roasting
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2018.01.243

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. [Display omitted] •A high temperature roasting was conducive to the leaching of Ag, Ga and Pb.•The leaching kinetics of silver in the tailings were analyzed.•The Ag, Ga and Pb in the tailings can be recovered by the chloride leaching.•The pollution risk of the leaching residue was substantially eliminated.