【作者】 张纯； 闵小波； 张建强； 王密；

【Author】 Zhang Chun;Min Xiaobo;Zhang Jianqiang;Wang Mi;Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University;School of Municipal and Mapping Engineering,Hunan City University;Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution;

【机构】 中南大学冶金与环境学院； 湖南城市学院市政与测绘工程学院； 国家重金属污染防治工程技术研究中心；

【摘要】 锌冶炼中浸渣中镉扩散至环境会造成生态系统镉污染。中浸渣中镉主要以铁酸锌镉形式存在。采用SO₂做还原剂,通过监测浸出液中镉离子浓度,研究了二氧化硫还原气氛、初始硫酸浓度、温度、液固比、二氧化硫分压及转速对锌焙砂中浸渣中镉浸出效率的影响。结果表明,SO₂做还原剂可以大大降低常规高温高酸处理方法的苛刻条件。反应的最佳工艺条件如下:初始硫酸浓度:80g/L;温度:95℃;液固比（L/S）:10 mL/g;二氧化硫分压:200k Pa;转速:400rpm;反应时间:120min。该工艺条件下,渣中镉的浸出率达到99%以上,满足对镉浸出率的要求。XRD和ICP分析表明,中浸渣中铁酸盐被分解,硫化物在该反应条件下难以浸出,还原浸出渣中主要化学成分为铅和锌,主要物相为PbSO₄和ZnS。更多还原

【Abstract】 Cadmium in zinc neutral leaching residue can lead to cadmium pollution of ecological system if it spread into environment. Cadmium mainly exists as the type of cadmium-bearing zinc ferrite. Sulfur dioxide was adopted as reductant to study the sulfur dioxide reduction atmosphere, initial sulfuric acid concentration, temperature, liquid-to-solid, sulfur dioxide partial pressure and stirring speed on the leaching efficiency based on the monitoring the concentration of cadmium in leaching solution. The results show that the reductive leaching by sulfur dioxide can weaken the traditional reactive conditions greatly. The optimum technological conditions are as follows: initial sulfuric acid concentration: 80g/L; temperature:95℃; liquid-to-solid:10; sulfur dioxide partial pressure:200 k Pa; stirring speed: 400rpm;reactive time:120min. Under these conditions, cadmium leaching efficiency reached more 99%. XRD and ICP analysis show that ferrite was decomposed and sulfide was hardly leached out in such conditions. The main chemical components are lead and zinc and the main phase are lead sulfate and zinc sulfide.更多还原