煤矸石中重金属元素赋存形态及释出特征研究

发布时间：2018-03-26 09:14

本文选题：煤矸石　切入点：形态分析　出处：《河南理工大学》2015年硕士论文

【摘要】：为探明煤矸石中重金属Cr、Ni、Cu、As、Cd、Pb的形态结构和释放机理,以及煤矸石山周围农田土壤的重金属污染现状,以河南省焦作市中马村矿为研究对象,并以新乡市赵固一矿和新密市米村矿为对照,采用BCR连续提取法分析了三个矿区煤矸石和农田土壤(中马村矿)中重金属元素的形态;对煤矸石进行了浸泡和淋溶实验,分析了煤矸石中重金属元素在浸泡和淋溶过程中的释放规律,讨论了重金属浸泡析出量与可交换态含量之间的关系。主要结果为:(1)中马村矿矸石中重金属Cr、Ni、Cd、As均以残渣态为主要赋存形态,Pb以残渣态和可还原态为主要形态,Cu的主要形态为残渣态和可氧化态。煤矸石中重金属元素的有效形态含量、总量与矸石粒径大小均无显著关系。生态风险评价结果表明,中马村矿煤矸石中重金属Ni、Cu的可交换态比例分别达到27.01%和21.41%,处于中度生态风险水平;米村矿煤矸石中重金属Ni、Cd均达到中度至高度生态风险;赵固一矿的Pb、Ni、Cu达到中度生态风险水平。单项污染系数评价结果表明:中马村土壤重金属污染系数均值大小排序为:CdAsPbCuNiCr,Cd元素全部样品均达到严重污染程度,Pb、As多数样品达到轻微污染,个别样品达到中度污染。(2)煤矸石一日浸泡实验的结果表明,重金属Ni和As在弱酸性浸泡液中更易被溶出释放;煤矸石经浸泡后的重金属析出量与矸石粒级无显著联系;中马村矿矸石中重金属Cu、Ni、As的释放浓度与其可交换态含量呈显著负相关,米村矿矸石中重金属Ni、Cd的释放浓度与其可交换态含量呈正相关。与国家地下水质标准对比,中马村、米村、赵固一矿三地矸石一日浸泡实验结果中均发现Ni、As元素浸出浓度均超过地下水水质标准,对环境存在一定风险。(3)煤矸石五日浸泡实验的结果表明,煤矸石中重金属Cd最易溶出,Pb最难溶出。重金属元素的溶出率大小排序为:中马村矿CdAsCrNiCu≈Pb;赵固一矿CdAsCrNiCuPb;米村矿CdAsCrNiCuPb。(4)煤矸石淋溶实验的结果表明,重金属Ni、Cu、As、Cd的释放量随时间的增长呈逐渐减少的趋势,最后趋于平稳,其淋溶释放峰值均出现于淋溶初期;重金属Pb、C的r淋溶释放规律均表现出波动性。(5)三个矿区煤矸石中重金属的溶出率均以As元素为最高;米村矿矸石中As元素的最大溶出率高于中马村矿和赵固一矿,达到1.0844%;矸石中Cd的最大溶出率以中马村矿为最低,仅为0.0253%;米村矿和赵固一矿矸石中重金属的最大溶出率均以Pb为最低。
[Abstract]:For heavy metals in coal gangue proved Cr, Ni, Cu, As, Cd, Pb morphology and release mechanism, and the heavy metal pollution in the farmland around coal gangue situation, in Macun city of Jiaozuo province in Henan coal mine as the research object, and takes Xinxiang city and Xinmi city zhaoguerkuang mine Micun mine as control. The three coal gangue and soil analysis method for continuous extraction of BCR (Macun mine) of heavy metal elements in the form; soaking and leaching experiments of coal gangue, analyzes the release law of heavy metal elements in coal gangue in soaking and leaching process, discussed the relationship between the heavy metal and immersion precipitation the exchangeable content. The main results are as follows: (1) the heavy metal Cr in Macun mine gangue, Ni, Cd, As in the residue as the main speciation, Pb in residual and reducible as the main form, the main form of Cu is residual fraction and oxidizable in coal gangue. The available form of heavy metals, there was no significant relationship between the total and gangue particle size. The ecological risk assessment results show that the heavy metal Ni in Macun coal mine, coal gangue, Cu of exchangeable ratio reached 27.01% and 21.41% respectively, in the moderate ecological risk level; heavy metal Ni Micun mine coal gangue, Cd are moderately to a high degree of ecological risk; Zhaogu No. Pb, Ni, Cu at moderate ecological risk level. The single pollution coefficient evaluation results show that: in Macun, the soil heavy metal pollution coefficient mean the order of CdAsPbCuNiCr, Cd elements in all samples have reached serious pollution, Pb, As in most samples reached slight pollution, moderate to individual samples the pollution of coal gangue. (2) a day immersion test results show that Ni and As are more susceptible to heavy metal release in acid soaking liquid; coal gangue were soaked in heavy precipitation and grain level Significant contact; heavy metals of Cu, in the Macun coal mine gangue Ni, concentration of As and the release of exchangeable content was significantly negatively related to heavy metal Ni Micun mine gangue, the release concentration of Cd and exchangeable content were positively correlated. Compared with the national standard of underground water in Macun, rice village, Zhao Ni were found the three day Gu mine gangue soak in the experimental results, As element leaching concentration exceeded the groundwater quality standards, there are certain risks to the environment. (3) coal gangue five days immersion test results show that the heavy metal Cd in coal gangue is most easily dissolved, Pb the most difficult dissolution of heavy metals. The dissolution rate of size order: in Macun mine is CdAsCrNiCu Pb; zhaoguerkuang mine CdAsCrNiCuPb; Micun mine CdAsCrNiCuPb. (4) coal gangue leaching experiment results show that the heavy metals Ni, Cu, As, Cd emissions were gradually decreased along with the increase of time, and finally tends to be stable, the leaching release Put the peak occurred in the early stage of leaching; leaching of heavy metals of Pb, release of R C fluctuated. (5) the three heavy metals in coal gangue dissolution rate of the As element is the highest; As element in Micun mine gangue in the maximum dissolution rate was higher than that in the Macun mine and zhaoguerkuang mine in Cd, reached 1.0844%; gangue maximum dissolution rate in Macun mine is the lowest, only 0.0253%; heavy metal mining and zhaoguerkuang mine gangue Micun maximum dissolution rates were the lowest in Pb.

【学位授予单位】：河南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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