Solidification/stabilization of heavy metals and its efficiency in lead-zinc tailings using different chemical agents
Solidification/stabilization of heavy metals and its efficiency in lead-zinc tailings using different chemical agents
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DOI：
10.1080/09593330.2020.1845817
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发表时间：
2020-11-24
影响因子：
2.8
通讯作者：
Mu, Yuandong
中科院分区：
文献类型：
--
作者：
Luo, Zhongtao;Tang, Changbo;Mu, Yuandong
铅锌尾矿是矿山开采过程中产生的一种固体废弃物，由于其重金属含量高，在自然状态下具有可回收性，因此被认为是危险固体废弃物。目前，处理固体废物中重金属最有效的技术是固化/稳定化（S/S）技术。就固硫技术而言，化学稳定化是最具潜力和实用性的方法之一。研究了四种典型化学药剂（Na 2S、NaH 2 PO 4、TMT和Na（2）EDTA）对铅锌尾矿中重金属的S/S特性。结果表明，螯合剂TMT比无机化学药剂Na 2S和NaH 2 PO 4更能有效稳定尾矿中的重金属铅和锌。当TMT用量为4%时，根据毒性特征浸出程序（TCLP），铅和锌的浸出浓度分别为0.18和14.60 mg/L，铅和锌的稳定效率分别为99.31%和80.92%。而加入10%NaH2PO4后，铅和锌的浸出浓度仅为0.41和16.00 mg/L。经4%Na2EDTA处理后，尾矿中重金属铅的浸出浓度高达53.44mg/L，远远超过污染控制标准。因此，综合考虑稳定效果和用量，TMT是铅锌尾矿中重金属固化剂的首选。
Lead-zinc tailings are generated during the mining process which is considered as hazardous solid waste due to its high heavy metal content and leachability in the natural state. At present, the most effective technology for disposing heavy metals in solid wastes is the solidification/stabilization (S/S) technique. In terms of S/S technology, chemical stabilization is one of the most potential and practical method. This paper aims to investigate the S/S property of four typical chemical agents (Na2S, NaH2PO4, TMT and Na(2)EDTA) on the heavy metals in lead-zinc tailings. The results reveal that the heavy metals lead and zinc in tailings are stabilized more effectively by using chelating agents TMT than by using inorganic chemical agents Na2S and NaH2PO4. When the dosage of TMT reaches 4%, the leaching concentration of lead and zinc is 0.18 and 14.60 mg/L according to toxicity characteristic leaching procedure (TCLP), and the stabilization efficiency of lead and zinc is 99.31% and 80.92%, respectively, while the leaching concentration of lead and zinc just drops to 0.41 and 16.00 mg/L with addition of 10% NaH2PO4. Furthermore, the leaching concentration of heavy metal lead in tailings treated by 4% Na(2)EDTA increases to 53.44 mg/L which far exceeds the standard of pollution control. Therefore, considering stabilization efficiency and dosage, TMT is the preferred agent for solidifying heavy metals in lead-zinc tailings.