Abstract：
The continued growth in demand for mineral resources has led to a large amount of mining wastes, which is a major challenge in the context of carbon neutrality and climate change. In this study, runoff migration, batch leaching, and column experiments were used to investigate the short-, medium-, and long-term leaching of heavy metals from legacy tailings, respectively; the cumulative metal release kinetic equations were established, and the long-term effects of tailings leaching were verified by HYDRUS-1D. In runoff migration experiments, surface dissolution of tailings and the co-migration of adsorbed soil particles by erosion were the main carriers in the early stages of leachate formation (Mn ∼ 65 mg/L and SO42- up to 2697.2 mg/L). Batch leaching tests showed that the concentration of heavy metals in soil leached by acid rain were 0.1 ∼ 22.0 μg/L for Cr, 0.7 ∼ 26.0 μg/L for Cu, 4.8 ∼ 5646.0 μg/L for Mn, 0.3 ∼ 232.4 μg/L for Ni, and 1.3 ∼ 448.0 μg/L for Zn. The results of column experiments indicated that some soluble components and metals with high mobility showed a significant decreasing trend at cumulative L/S ≤ 2. Additionally, the metals have higher leaching rates under TCLP conditions, as shown by Mn > Co > Zn > Cd > Ni > Cu > Pb > Cr. The fitting results of Langmuir equation were closer to the cumulative release of metals in the real case, and the release amounts of Mn, Zn, Co, and Ni were higher with 55, 5.84, 2.66, and 2.51 mg/kg, respectively. The water flow within tailings affects the spatial distribution of metals, which mainly exist in relatively stable chemical fractions (F3 + F4 + F5 > 90 %) after leaching. Numerical simulation verified that Mn in leachate has reached 8 mg/L at a scale of up to 100 years. The research results are expected to provide technical basis for realizing the resource utilization of tailings in the future.
摘要：
对矿产资源需求的持续增长导致了大量的采矿废物，在碳中和和气候变化的背景下，这是一个重大挑战。在这项研究中,径流迁移，分批浸出，和柱实验用于研究短，medium-,以及从传统尾矿中长期浸出重金属，分别建立了累积金属释放动力学方程，并通过HYDRUS-1D验证了尾矿浸出的长期效果。在径流迁移实验中，在渗滤液形成的早期阶段（Mn〜65mg/L和SO42-高达2697.2mg/L），尾矿的表面溶解和通过侵蚀的吸附土壤颗粒的共同迁移是主要载体。分批淋溶试验表明,酸雨淋溶土壤中重金属含量为0.1~22.0μg/L,Cu为0.7~26.0μg/L，对于Mn，4.8~5646.0μg/L，Ni为0.3〜232.4μg/L，锌为1.3~448.0μg/L。柱实验结果表明，在累积L/S≤2时，一些可溶性成分和高迁移率金属呈显著下降趋势。此外,在TCLP条件下，金属具有较高的浸出率，如Mn>Co>Zn>Cd>Ni>Cu>Pb>Cr所示。Langmuir方程的拟合结果更接近实际情况下金属的累积释放量,以及Mn的释放量，Zn,Co,Ni较高，分别为55、5.84、2.66和2.51mg/kg，分别。尾矿内的水流影响金属的空间分布，主要存在于浸出后相对稳定的化学组分中(F3+F4+F5>90%)。数值模仿证实，在长达100年的规模内，渗滤液中的Mn已到达8mg/L。研究成果有望为今后实现尾矿资源化利用提供技术依据。
