铅锌尾矿固结体的重金属长期稳定性及机理  

Long-term Stability and Mechanisms of Heavy Metals in Lead-Zinc Tailings Consolidation Blocks

作　　者：王豪杰 黄绪泉[1,2] 薛菲 侯浩波[3] WANG Haojie;HUANG Xuquan;XUE Fei;HOU Haobo(Engineering Research Center of Eco-environment in Three Gorges Reservoir Region of Ministry of Education,China Three Gorges University,Yichang 443002,China;College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,China;School of Resource and Environment Science,Wuhan University,Wuhan 430072,China)

机构地区：[1]三峡库区生态环境教育部工程研究中心,湖北宜昌443002 [2]三峡大学水利与环境学院,湖北宜昌443002 [3]武汉大学资源与环境科学学院,湖北武汉430072

出　　处：《环境科学与技术》2025年第2期50-59,共10页Environmental Science & Technology

基　　金：湖北省自然科学基金项目(2024AFB158);宜昌市自然科学基础研究基金项目(A24-3-007);国家重点研发计划项目(2018YFC1801703)。

摘　　要：目前,固化/稳定化技术仍是降低大宗重金属废物环境风险的有效途径之一,但重金属在固化后离子总量不变,并全部转存于固结体中,极易引发有毒重金属二次释放的潜在环境风险。该文以70%(w)铅锌尾矿(LZTs)占比制备的LZTs固结体(LZTCBs)为研究对象,通过半动态浸出试验,模拟不同自然侵蚀条件下LZTCBs中重金属的释放特性,探究固结体的重金属扩散模型并量化其长期环境稳定性能,并揭示LZTCBs中重金属的长期稳定固化机理。结果表明:LZTCBs在模拟地表/下水、酸性降雨和卫生填埋场渗滤液中Pb、Zn、Cr和Cd的释放机制为扩散控制,扩散系数分布在5.38×10^(-14)~2.98×10^(-8)cm^(2)/s,重金属污染离子流动性较低;经过100 a的模拟扩散,LZTCBs中Pb、Zn、Cr和Cd扩散面积分布在1.70×10^(-4)cm^(2)~1.83 m^(2),基本上在源头控制了重金属的释放;LZTCBs中重金属Pb、Zn、Cr和Cd主要通过化学沉淀、固溶体形成与吸附和物理固封的协同作用实现稳定化。由70%掺比制备的LZTCBs,可用于道路基础、矿山充填和采石场修复等实际工程,为实现有毒重金属废物的无害化和资源化利用提供了一条可行途径。Presently,solidification/stabilization technology is still one of the effective ways to reduce the environmental risk of bulk heavy metal waste,but the total amount of heavy metal ions remains unchanged after solidification,and all of them are transferred to the consolidated body,which easily leads to the potential environmental risk of secondary release of toxic heavy metals.This article with LZTs consolidated body(LZTCBs)prepared from 70%(w)lead and zinc tailings(LZTs)was taken as the research object.Semi-dynamic leaching test was conducted to simulate the release characteristics of heavy metals in LZTCBs under different natural erosion conditions,explore the heavy metal diffusion model of the consolidated body and quantify its long-term stability performance,and reveal the long-term stability chemical mechanism of heavy metals in LZTCBs.The results show that the release mechanism of Pb,Zn,Cr and Cd from LZTCBs in simulated surface/water,acid rainfall and sanitary landfill leachate is diffusion control,with diffusion coefficients ranging from 5.38×10^(-14) to 2.98×10^(-8) cm^(2)/s,and the fluidity of heavy metal ions is low.After 100 years of simulated diffusion,the diffusion area of Pb,Zn,Cr and Cd in LZTCBs is 1.70×10^(-4) cm^(2)~1.83 m^(2),which basically controls the release of heavy metals at the source.The heavy metals Pb,Zn,Cr and Cd in LZTCBs are stabilized synchronously through the synergistic effects of chemical precipitation,solid solution formation,adsorption and physical solid sealing.LZTCBs with“critical particle size-low alkali excitation-normal tempera-ture preparation”provides a feasible way to realize long-term harmless and full resource utilization of heavy metals in LZTs simultaneously.

关 键 词：铅锌尾矿 固结体 重金属 模拟扩散 长期稳定性 

分 类 号：X757[环境科学与工程—环境工程]