摘要
Zinc neutral leaching residue（ZNLR） from hydrometallurgical zinc smelting processing can be determined as hazardous intermediate containing considerable amounts of Cd and Zn which have great threats to the environment. The ZNLR contained approximately 35.99% Zn, 15.93% Fe and 0.26% Cd, and Cd mainly existed as ferrites in the ZNLR in this research. Reductive acid leaching of ZNLR was investigated. The effects of hydrazine sulfate concentration, initial sulfuric acid concentration, temperature, duration and liquid-to-solid ratio on the extraction of Cd, Zn and Fe were examined. The extraction efficiencies of Cd, Zn and Fe reached 90.81%, 95.83% and 94.19%, respectively when the leaching parameters were fixed as follows： hydrazine sulfate concentration, 33.3 g/L; sulfuric acid concentration, 80 g/L; temperature, 95 °C; duration of leaching, 120 min; liquid-to-solid ratio, 10 m L/g and agitation, 400 r/min. XRD and SEM-EDS analyses of the leaching residue confirmed that lead sulfate（Pb SO4） and hydrazinium zinc sulfate（（N2H5）2Zn（SO4）2） were the main phases remaining in the reductive leaching residue.
湿法炼锌中性浸出渣(中浸渣)是含有Cd和Zn等重金属元素的一种危险中间物料,对环境造成严重危害。本研究所用锌中浸渣含有约35.99%Zn、15.93%Fe和0.26%Cd,而Cd主要以铁酸盐的形式存在。研究硫酸肼浓度、硫酸初始浓度、温度、时间以及液固比对酸性还原浸出锌中浸渣Cd、Zn和Fe浸出率的影响。结果表明,中浸渣在硫酸肼浓度为33.3 g/L、硫酸初始浓度为80 g/L、浸出温度为95°C、液固比为10 m L/g、搅拌速度为400 r/min条件下还原浸出120 min,Cd、Zn和Fe的浸出率分别达90.81%、95.83%和94.19%。X射线衍射及扫描电镜-能谱分析显示还原浸出渣的主要物相为硫酸铅(Pb SO4)以及硫酸锌肼复盐((N2H5)2Zn(SO4)2)。
基金
Project(2012FJ1010)supported by the Key Project of Science and Technology of Hunan Province
China
Project(51474247)supported by the National Natural Science Foundation of China
Project(2012GS430201)supported by the Science and Technology Program for Public Wellbeing
China
