不同氧化还原条件下铅锌矿尾砂中重金属元素活化迁移规律

以广西大厂镇鲁塘铅锌矿尾砂为研究对象，通过淋滤实验研究了不同氧化还原条件下尾砂中Cu、Cd、Zn、Pb和As等元素的活化和迁移规律。结果表明：经高浓度氧化、高浓度还原条件处理的尾矿表现为pH<7的酸性环境，经低浓度氧化环境条件处理的尾砂呈现pH>7的弱酸性至弱碱性环境；尾砂中Cu、Cd元素活化迁移受pH值的影响明显，即高浓度还原和高浓度氧化条件可以促进Cu和Cd元素的迁移，酸性条件对Cu和Cd元素的迁移起到促进作用；Zn与Cd元素存在竞争吸附关系，但二者仍有明显差别；Pb和As元素受到还原条件的影响，能有效促进Pb和As元素的释放迁移。在淋滤实验前期，铅锌矿的表面阻力较小，由于环境酸碱性的改变，初始尾砂对重金属元素的吸附位能发生变化，重金属元素初期迁移能力得到加强；淋滤后期，矿物颗粒表面由于发生氧化还原反应，促使颗粒表面的阻力增加，重金属元素的溶出量减少，迁移能力受到抑制。

Activation and Migration of Heavy Metal Elements in Lead Zinc OreTailings Under Different Redox Conditions

Taking the tailings sand of Lutang lead and zinc mine in Guangxi as the research object, the activation and migration law of Cu, Cd,  Zn,  Pb, As  and other elements in tailings sand under different oxidation and reduction conditions was studied by leaching experiments. The results showed that the tailings treated with high concentration oxidation and high concentration reduction conditions showed the acidic environment with pH <7, and showed weak acidity to weak alkaline environment with pH>7 under the treatment of low concentration oxidation environmental conditions. The activation and migration of Cd is obviously affected by pH, that is, high concentration reduction, high oxidation, and acidic conditions can promote the migration of Cu and Cd; While reducing conditions can effectively promote the release and migration of Pb and As. The surface resistance of lead and zinc ore is small in the pre-filtration experiment,  and the migration ability of heavy metal elements in the initial stage is strengthened. The adsorption energy level of the initial tailings for heavy metal elements is changed by the change of ambient acidity and alkalinity. Later in the leaching period, the surface resistance of the mineral particle is increased due to the redox reaction, the dissolved amount of heavy metal elements is decreased, and the migration ability is inhibited.