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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)。
Zinc hydrometallurgical leaching residue (middle leaching residue) is a dangerous intermediate material containing heavy metals such as Cd and Zn, causing serious environmental damage. The zinc leach residue used in this study contains about 35.99% Zn, 15.93% Fe and 0.26% Cd, whereas Cd is mainly present as ferrite. The effects of concentration of hydrazine sulfate, initial concentration of sulfuric acid, temperature, time and ratio of liquid to solid on leaching rates of Cd, Zn and Fe from leaching residue by acid reduction were investigated. The results showed that the medium leaching residue was obtained under the conditions of hydrazine sulfate concentration of 33.3 g / L, sulfuric acid initial concentration of 80 g / L, leaching temperature of 95 ° C, liquid-solid ratio of 10 m L / g and stirring speed of 400 r / min The leaching rates of Cd, Zn and Fe reached 90.81%, 95.83% and 94.19% respectively after being reduced and leached for 120 min. X-ray diffraction and scanning electron microscopy-energy spectrum analysis showed that the main phases of the leaching residue were lead sulfate (Pb SO4) and zinc (II) sulfate complex salt ((N2H5) 2Zn (SO4) 2).