锌渣的氯盐浸液锌粉置换沉银与硫化沉银研究

Study on Ag Replacement with Zinc Powder and Precipitation of Ag and Pb with Sodium Sulfide from Chloride Leaching Solution of Zinc Slag

对湿法炼锌过程产生的锌废渣进行焙烧—酸浸—氯盐浸出得到的氯盐浸液进行锌粉置换沉银及硫化沉银和铅的研究。锌粉置换沉银最佳条件为:锌粉用量9~10倍理论量、反应温度25℃、置换时间1.0h,银的置换率达到97%以上;硫化沉淀的最佳条件为:硫化钠用量1倍理论量、反应温度室温、反应时间1.0h,铅和银的沉淀率分别为99.86%和98.6%。硫化沉银后液配制的饱和氯化钠溶液二次浸出酸浸渣,在液固比5、90℃浸出4h时,银和铅的浸出率分别为94.11%和90%,铅在氯盐浸渣中的含量为1.03%,硫化沉银后液可循化作为酸浸渣的氯盐浸出剂使用。

Ag was replaced by zinc powder and Ag/Pb was precipitated by sodium sulfide from chloride leaching solution of zinc slag from zinc hydrometallurgy applying roasting-acid leaching-chloride leaching.Ag replacing rate is 97% above under the optimum conditions including dosage of zinc powder of 9~10times theoretical quantity,reaction temperature of 25℃,and reaction time of 1h.Precipitating rate of Ag and Pb is 99.86%and 98.6%respectively under the optimum conditions including dosage of sodium sulfide of one time theoretical quantity,room temperature,and reaction time of 1.0h.Acid leaching residue was leached by saturated NaCl solution prepared from sulfide liquid after Ag precipitation for 1.0hat room temperature with L/S=5,leaching rate of Ag and Pb is 94.11%and 90%respectively,and lead content in chloride leaching residue is 1.03%.Solution after Ag precipitation with sodium sulfide can be reused as chloride leaching agent of acid-leaching residue.