Clean and Efficient Recovery of Precious Metals from Ag-Rich Lead Slime Anode

Abstract

Lead anode slime (LAS), a significant by-product for Ag and Au recovery, is produced from lead electro-refining process. The volume of Ag recycled from LAS accounts for approximately 60% share of global silver production. Limited understanding of complex characteristics of the metals in LAS and prominent problems of difficult efficient separation, complex process, and serious environmental pollution in traditional LAS processing for PMs recovery have been highlighted as significant knowledge gaps. An innovative directional vacuum volatilization of LAS for Ag and Au enrichment is therefore proposed. Results indicated that Ag and Au were successfully enriched in residues, while impurities of As2O3, Sb2O3, etc., were collected in volatiles. The direct recovery of Ag and Au reached 99.0%. Vacuum strategy not only effectively extracted Ag and Au but also avoided arsenic contamination. The finding will be significant to benefit decision-making direction for clean-efficient utilization of LAS.