Recovery of valuable metals from zinc leaching residue by sulfate roasting and water leaching

硫酸盐化焙烧-水浸回收锌浸渣中有价金属（英文）

Zinc leaching residue(ZLR),produced from traditional zinc hydrometallurgy process,is not only a hazardous waste but also a potential valuable solid.The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR.The ZLR was initially roasted with ferric sulfate at640°C for1h with ferric sulfate/zinc ferrite mole ratio of1.2.In this process,the valuable metals were efficiently transformed into water soluble sulfate,while iron remains as ferric oxide.Thereafter,water leaching was conducted to extract the valuable metals sulfate for recovery.The recovery rates of zinc,manganese,copper,cadmium and iron were92.4%,93.3%,99.3%,91.4%and1.1%,respectively.A leaching toxicity test for ZLR was performed after water leaching.The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.

锌浸渣产生于传统湿法炼锌过程,它是一种危险废物同时也是一种潜在的有价固体废物。用硫酸盐化焙烧-水浸的组合工艺对锌浸渣中有价金属进行回收。首先,锌浸渣在640°C下与硫酸铁进行混合焙烧,硫酸铁/铁酸锌摩尔比为1.2,硫酸盐化焙烧时间为1 h。在此过程中,废渣中的有价金属转化为可溶的硫酸盐,而铁以氧化铁形式存在。随后,采用水浸法提取有价金属硫酸盐,渣中锌、锰、铜、镉、铁的回收率分别为92.4%、93.3%、99.3%,91.4%,1.1%。对水浸处理后的废渣进行浸出毒性检测。结果表明,上述工艺可以有效地实现锌浸渣的无害化处理,处理后各重金属浸出毒性均低于限值。