(1. 中南大学 冶金与环境学院，长沙 410083；
2. 湖南城市学院 市政与测绘工程学院，益阳 413000；
3. 中南大学 国家重金属污染防治工程技术研究中心，长沙 410083)
摘 要: 以锌冶炼中浸渣为研究对象，研究中浸渣的化学成分及锌的存在形态，锌主要以铁酸锌形式存在。采用SO2做还原剂，研究温度、初始硫酸浓度、二氧化硫分压对锌浸出效率的影响，并分析中浸渣中锌还原浸出反应机制及动力学。结果表明：H+在锌还原浸出过程中起关键作用，锌还原浸出反应活化能为31.67 kJ/mol，为化学反应控制；SO2做还原剂时，反应时间、液固比及初始酸度均大幅降低。反应最佳工艺条件：初始硫酸浓度80 g/L、温度95 ℃、液固比(L/S) 10 mL/g、二氧化硫分压200 kPa、反应时间120 min。该工艺条件下，中浸渣中锌浸出率达99%以上。XRD和ICP分析表明：中浸渣中铁酸锌分解，硫化锌在该反应条件下未完全浸出，还原浸出渣中主要化学成分为铅和锌，主要物相为PbSO4和ZnS。
关键字: 中浸渣；还原浸出；二氧化硫；动力学
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China;
3. Chinese National Engineering Research Center for Control and Treatment of
Heavy Metal Pollution, Central South University, Changsha 410083, China）
Abstract:The chemical composition and zinc phases were studied by XRD, XPS, ICP and phase analysis. The effects of temperature, initial sulfuric acid concentration and partial pressure of sulfur dioxide on the Zn leaching rate were also studied when sulfur dioxide was used as reductant. The mechanism and kinetics of reductive decomposition of zinc ferrite were also studied. The results show that H+ plays a key role during the reductive leaching process. The activity energy is 31.67 kJ/mol and the kinetic equation is established based on the chemical reaction controlled model. The optimum technological conditions are as follows: initial sulfuric acid concentration 80 g/L; temperature 95 ℃; liquid-to-solid 10; sulfur dioxide partial pressure 200 kPa; reactive time 120 min. Under the optimum condition, zinc leaching efficiency reached more than 99% and the main phase in the reductive residue are lead sulfate and zinc sulfide.
Key words: zinc neutral leaching residue; reductive leaching; sulfur dioxide; kinetics
