School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China.
School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China; Hubei Environmental Remediation Material Engineering Technology Research Center, Wuhan, 430072, PR China.
Environ Pollut. 2022 Aug 15;307:119529. doi: 10.1016/j.envpol.2022.119529. Epub 2022 May 24.
In acidic medium, hazardous heavy metals of lead-zinc tailing (LZT) are easily leachable and mobilizable. Thus, the hazard, amount, form, and complexity of the leached heavy metals under acidic precipitation become a major environmental concern. This work investigates the gangue minerals, toxicity, speciation, leaching characteristics of heavy metals in LZT under simulated acid rain, as well as immobilization effects and mechanisms using a sustainable binder. In LZT, dolomite, quartz, calcite, and muscovite are the main gangue minerals, tiny hazardous metallic minerals were absorbed in the surface. The results revealed that Pb, Zn, Cr, and Cd were the predominant harmful elements, particularly Pb and Zn. Zn is leached completely and is the concerned hazardous element under simulated acid rain. In the acid rain neutralization ability test, the amount of leachable Pb, Cr, Ca, and Si maintained in equilibrium, leached Zn, Cd, Al, and Mg depended on the addition of acid. Pb and Ca were sedimented in residues. Immobilization of Pb, Zn, Cr, and Cd depended on the stability of Ca(OH)/C-S-H of hydrates, and 70% LZTHP after curing 7 days can be used for some practical engineering projects. This work opens up deeply understandings for the leached heavy metals under acidic precipitation and improves the sustainable and safe in the field of immobilization of heavy metals.
在酸性介质中，铅锌尾矿（LZT）中的有害重金属很容易浸出和迁移。因此，在酸性降水下浸出重金属的危害、数量、形态和复杂性成为主要的环境关注点。本研究采用可持续粘结剂，调查了模拟酸雨条件下 LZT 中的脉石矿物、毒性、形态、重金属浸出特性以及重金属的固定化效果和机制。在 LZT 中，白云石、石英、方解石和云母是主要的脉石矿物，微小的有害金属矿物被吸附在表面。结果表明，Pb、Zn、Cr 和 Cd 是主要的有害元素，尤其是 Pb 和 Zn。Zn 完全浸出，是模拟酸雨下的关注有害元素。在酸雨中和能力测试中，可浸出 Pb、Cr、Ca 和 Si 的量保持平衡，浸出 Zn、Cd、Al 和 Mg 取决于酸的添加量。Pb 和 Ca 沉淀在残渣中。Pb、Zn、Cr 和 Cd 的固定化取决于水合产物中 Ca(OH)/C-S-H 的稳定性，养护 7 天后 70%的 LZTHP 可用于一些实际工程项目。这项工作为深入了解酸性降水下的重金属浸出情况，并提高重金属固定化领域的可持续性和安全性提供了新的思路。
