Huang Xuquan, Sun Zhenghua, Zhao Yanhui, Wang Haojie, Xue Fei, Hou Haobo
Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, PR China; College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China.
College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China.
J Hazard Mater. 2024 May 5;469:133882. doi: 10.1016/j.jhazmat.2024.133882. Epub 2024 Feb 24.
Hazardous mine tailings (HMTs) dam failures can cause devastation to the ecology environment, people's lives and property, which require expensive and complicated remediation engineering systematacially. A cheap and sustainable inertization disposal is proposed for de-risking HMTs without any carbon emissions, stabilizing hazardous heavy metal cations within safety minerals and also sequestering CO in the process, simultaneously. Herein, lead-zinc tailings as target HMTs were inertized by using waste rice husk ashes (RHAs) and carbide slag (CS) with a certain ratio, and lead-zinc tailings hardened pastes (LZTHPs) were investigated based on the experimental performance, analytical characteristics, and simulation diffusion methods, to deeply unveil the minerals transformation mechanisms and long-term stability from the cation perspectives. Results revealed that LZTHPs' compressive strength ranged from 1.04-4.73 MPa and leaching toxicity concentrations of Pb, Zn, Cr, and Cd reached 0.03 mg/L, 1.78 mg/L, 0.01 mg/L, and 0.01 mg/L, respectively. C-S-H gels (Type I and II), cation hydroxides and CO mineralization carbonates were the hydrates in LZTHPs. Pb (86%), Zn (78%), Cr (76%), and Cd (65%) were immobilized as residual state, and CO mineralization capacity was 0.16 kg/kg. The diffusion coefficient of Pb, Zn, Cr, and Cd below 4.48 × 10 cm/s, 1.39 × 10 cm/s, 4.72 × 10 cm/s, and 0.30 × 10 cm/s, which would be sufficient in most scenarios to adequately stabilize tailings. Diffusion control is the leaching mechanism of cations. After 100 years of simulation diffusion, the diffusion areas of Pb, Zn, Cr, and Cd are 1.33 × 10∼1.49 cm, 2.47 × 10∼0.48 cm, 2.47-8.61 × 10 cm, and 1.49 cm, respectively, and the environmental impact of LZTHPs was negligible. This study provides promising solutions for alleviating hazardous tailings dangerous, achieving sustainable development with zero-carbon emission, implying the concept of eliminating waste by waste, synchronously.
危险矿尾矿（HMTs）坝体溃坝会对生态环境、人民生命财产造成破坏，这需要进行昂贵且复杂的系统性修复工程。本文提出一种廉价且可持续的固化处置方法，用于降低HMTs风险，该方法无碳排放，能将有害重金属阳离子稳定在安全矿物中，同时在过程中封存CO。在此，以铅锌尾矿作为目标HMTs，使用一定比例的废弃稻壳灰（RHAs）和电石渣（CS）对其进行固化，并基于实验性能、分析特性和模拟扩散方法对铅锌尾矿硬化浆体（LZTHPs）进行研究，从阳离子角度深入揭示矿物转化机制和长期稳定性。结果表明，LZTHPs的抗压强度范围为1.04 - 4.73MPa，Pb、Zn、Cr和Cd的浸出毒性浓度分别达到0.03mg/L、1.78mg/L、0.01mg/L和0.01mg/L。C - S - H凝胶（I型和II型）、阳离子氢氧化物和CO矿化碳酸盐是LZTHPs中的水化物。Pb（86%）、Zn（78%）、Cr（76%）和Cd（65%）以残留态固定，CO矿化能力为0.16kg/kg。Pb、Zn、Cr和Cd的扩散系数分别低于4.48×10cm/s、1.39×10cm/s、4.72×10cm/s和0.30×10cm/s，在大多数情况下足以充分稳定尾矿。阳离子的浸出机制是扩散控制。经过100年的模拟扩散，Pb、Zn、Cr和Cd的扩散面积分别为1.33×10∼1.49cm、2.47×10∼0.48cm、2.47 - 8.61×10cm和1.49cm，LZTHPs对环境的影响可忽略不计。本研究为减轻危险尾矿危害、实现零碳排放的可持续发展提供了有前景的解决方案，同时意味着以废治废的理念。
