凤县安河流域铅锌尾矿重金属污染评价和淋溶特性研究

发布时间：2018-07-31 14:24

【摘要】：矿业生产活动产生了大量的尾矿废弃物。目前尾矿中高浓度的重金属已经成为土壤环境重金属污染的重要来源,直接或者间接地危害动植物和人类的生命健康。本研究从废弃尾矿长期堆放现状导致的重金属污染问题出发,以治理尾矿重金属污染为基本目标,在查阅大量相关文献和利用环境化学等学科知识的基础上,以凤县安河流域铅锌尾矿为研究对象,调查了铅锌尾矿和周围耐性植物重金属含量状况,并评价了铅锌尾矿的污染状况。在此基础上,通过柱淋洗和BCR的方法评价了2种常用的钝化剂-氧化钙和竹炭在铅锌尾矿重金属污染治理上的实际效果。主要得出了以下结论:1.铅锌尾矿中重金属Cu、Zn、Pb和Cd含量较大,分别为131、3332、4474和140mg/kg。周边荩草的地上部分Zn含量较高,为683 mg/kg。中国繁缕的地上部分Pb和Zn含量都较高,分别为757和702 mg/kg。可作为潜在的土壤重金属修复植物。2.通过潜在生态风险指数法评价凤县安河流域铅锌尾矿对环境造成的影响,发现铅锌尾矿中重金属Zn对环境有中等的生态风险,重金属Cd和Pb会对环境存在极强的生态风险,铅锌尾矿的综合潜在生态风险指数为6673,表现为极强,亟需治理。3.柱淋洗实验中铅锌尾矿淋出液的pH一般在7.88~8.89之间,添加1%氧化钙作为钝化剂的B柱淋出液的pH却大大不同,在12.80~13.03之间。4.使用氧化钙作为钝化剂的铅锌尾矿淋洗实验表明,河水对于重金属的溶出效果好于酸雨和去离子水。使用竹炭作为钝化剂的铅锌尾矿淋洗实验显示,河水和酸雨的重金属溶出效果好于蒸馏水。5.通过淋溶实验和BCR实验分析了添加1%氧化钙作稳定化处理的铅锌尾矿样,发现氧化钙对重金属Cd和Zn有较好的钝化效果,对重金属Cu和Pb稳定化能力较差。6.通过淋溶实验和BCR实验分析了添加1%竹炭作稳定化处理的铅锌尾矿样,发现竹炭对重金属Cd、Pb和Zn有较好的稳定化作用,对铅锌尾矿中的Cu稳定化能力较差。
[Abstract]:Mining activities produce a large amount of tailings waste. At present, the high concentration of heavy metals in tailings has become an important source of heavy metal pollution in soil environment, which directly or indirectly endangers the life and health of animals and plants and human beings. Based on the problem of heavy metal pollution caused by the long-term stacking of waste tailings, the basic goal of this study is to control the heavy metal pollution of tailings, on the basis of consulting a large number of relevant documents and utilizing the knowledge of environmental chemistry, etc. Taking lead and zinc tailings in Anhe Valley of Fengxian County as the research object, the contents of heavy metals in lead and zinc tailings and their surrounding tolerant plants were investigated, and the pollution status of lead and zinc tailings was evaluated. On this basis, the practical effects of two common passivators, calcium oxide and bamboo charcoal, on the treatment of heavy metal pollution in lead-zinc tailings were evaluated by column elution and BCR. The main conclusions are as follows: 1. The contents of Pb and CD in the tailings of lead and zinc are 131C 3332N 4474 and 140 mg / kg respectively. The content of Zn in the aboveground part was higher, which was 683 mg / kg 路kg ~ (-1) 路m ~ (-1). The contents of Pb and Zn in the aboveground parts of Zoysia japonica were 757 and 702 mg / kg, respectively. It can be used as a potential soil heavy metal remediation plant. The potential ecological risk index method was used to evaluate the impact of lead and zinc tailings on the environment in Anhe basin of Fengxian County. It was found that the heavy metal Zn in lead and zinc tailings had moderate ecological risk to the environment, and CD and Pb had a strong ecological risk to the environment. The comprehensive potential ecological risk index of lead-zinc tailings is 6673, which is very strong and needs to be treated urgently. In the column elution experiment, the pH of the leaching solution of lead-zinc tailings was generally between 7.88 and 8.89, but the pH of the B-column leaching solution with 1% calcium oxide as passivating agent was significantly different, ranging from 12.80 to 13.03. The leaching experiment of lead-zinc tailings using calcium oxide as passivating agent shows that the leaching effect of river water on heavy metals is better than acid rain and deionized water. The leaching experiment of lead-zinc tailings using bamboo charcoal as passivating agent showed that the leaching effect of heavy metals in river water and acid rain was better than that in distilled water .5. The samples of lead-zinc tailings treated with 1% calcium oxide as stabilizer were analyzed by leaching and BCR experiments. It was found that calcium oxide had a better passivation effect on heavy metals CD and Zn, and a poor stabilizability of Cu and Pb. The lead-zinc tailings treated with 1% bamboo charcoal as stabilizer were analyzed by leaching experiments and BCR experiments. It was found that bamboo charcoal had a good stabilizing effect on heavy metals CD, Pb and Zn, but not on Cu in lead-zinc tailings.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X82;X753

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