Recovery of zinc and silver from zinc acid-leaching residue by sulphation roasting-water leaching of zinc and iron-silver chlorination leaching method

摘要

Recovering zinc and silver from zinc acid-leaching residue was investigated in this study. The process of sulphation roasting, water leaching, silver chlorination leaching, PbCl2 crystallization and lead replacement was used. The leaching rate of zinc and iron is 92.66% and 94.67% when sulphation roasting temperature is 300 °C, sulphate consumption is 70∼84 g Hectogram material, time is 120 min. Leach liquor retain to main process to recover zinc. Under the conditions that the concentrations of Fe3+, Cl− and H+ is 18g·L−1, 250 g·L−1 and 2.3mol ·L−1 separately, leaching temperature is 95 °C±1, mechanical agitation for 1.5 h. Leaching rate of silver and lead is 94.17% and 97.89%. Coarse silver powder was prepared by lead-cementation and cementation rate is higher than 99%.