Abstract:
During the oxygen pressure leaching process for zinc refining in a hydrometallurgical zinc-refining plant in Yunnan, large quantities of silver-bearing zinc-sulfur residue are produced. To effectively recover silver from this residue, the process parameters of silver recovery via thiourea leaching were systematically investigated. The results revealed that thiourea leaching has a significant chemical reaction driving force, with a binding energy of 83.9 kJ/mol on the silver surface. Under optimal conditions of a liquid-solid ratio of 8∶1, thiourea dosage of 10 g/L, leaching time of 2 h, leaching temperature of 50 °C, pH value of 1.5, and Fe
3+ concentration of 0.3 mol/L, a silver leaching rate of 85.71% was achieved. The study provides a scientific basis for efficient silver recovery from zinc-sulfur residue and theoretical support for the further application of the thiourea method in hydrometallurgical zinc-refining processes. This approach contributes to the comprehensive recovery and utilization of silver resources in hydrometallurgical zinc production and has the potential to generate significant economic benefits for enterprises.