| 宁东能源化工基地粉煤灰重金属赋存特征及生态风险评价 |
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| 引用本文： | 张治国,谭雨柠,胡友彪,郑永红,陈登红,蔡维卿,李雅婷,卢江伟.宁东能源化工基地粉煤灰重金属赋存特征及生态风险评价[J].煤田地质与勘探,2022,50(11):144-152. |
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| 作者姓名： | 张治国 谭雨柠 胡友彪 郑永红 陈登红 蔡维卿 李雅婷 卢江伟 |
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| 作者单位： | 1.安徽理工大学 地球与环境学院，安徽 淮南 232001 |
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| 基金项目： | 合肥综合性国家科学中心能源研究院项目(21KZS217)；国家自然科学基金项目(51904014)；国家重点研发计划重点专项项目(2020YFC1908601) |
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| 摘 要： | 为拓展粉煤灰的资源化利用，以宁夏宁东能源化工基地鸳鸯湖电厂粉煤灰为研究对象，使用扫描电镜、能谱分析和X射线衍射等测试方法对粉煤灰理化特性进行表征和分析，并采用酸消解法、DTPA浸提法和Tessier五步提取法，对粉煤灰中铅(Pb)、铬(Cr)、镍(Ni)、铜(Cu)、镉(Cd)和砷(As)6种重金属的全量、有效态、不同形态含量进行了测定。采用风险评价编码法(RAC)、次生相与原生相比值法(RSP)和潜在生态风险指数法评估粉煤灰重金属生态风险。结果表明:(1) 粉煤灰微观结构良好，密度小，速效钾和速效磷含量丰富。(2) 粉煤灰中6种重金属元素全量和平均值均超过宁夏地区土壤环境背景值，但未超过其他农用地土壤污染风险筛选值(基本项目)，超标倍数大小顺序为Pb、Cu、Cr、As、Cd、Ni。6种重金属元素有效态含量均未超过宁夏地区土壤环境背景值和其他农用地土壤污染风险筛选值。(3) RAC评价结果表明，As具有极高生态风险，Cd、Cu和Ni具有中高风险，Cr、Pb分别为低风险和无风险。RSP评价结果表明，重金属As为轻度污染，Pb、Cr、Ni、Cu、Cd均为无污染。潜在生态风险指数法结果表明，粉煤灰中6种元素全量和有效态潜在生态危害指数(RI)处于Ⅰ级，轻微生态危害水平，其中Cd是生态风险的主要贡献元素。因此，粉煤灰可以作为煤矿胶结充填材料进行大规模资源化利用。
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| 关 键 词： | 宁东能源化工基地 粉煤灰 重金属 赋存形态 生态风险评价 |
| 收稿时间： | 2021-05-18 |
Occurrence characteristics and ecological risk assessment of heavy metals in fly ash of Ningdong Energy Chemical Industry Base |
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| Institution: | 1.School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China2.Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China3.Anhui Engineering Laboratory for Comprehensive Utilization of Water and Soil Resources and Ecological Protection in Mining Area with High Groundwater Level, Huainan 232001, China4.School of Mining Engineering, Anhui University of Science and Technology, Huainan 232001, China |
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| Abstract: | In order to expand the resource utilization of fly ash, research was conducted based on the fly ash of Yuanyang Lake Power Plant in the Ningdong Energy Chemical Industry Base. Specifically, the physical and chemical properties of fly ash were characterized and analyzed by means of scanning electron microscope, energy spectrum analysis and X-ray diffraction. Besides, the total amount, effective state and content in different forms of Pb, Cr, Ni, Cu, Cd and As in fly ash were determined through acid digestion, DTPA extraction and 5-step Tessier sequential extraction. In addition, the ecological risk of heavy metals in fly ash was assessed with the risk assessment coding method (RAC), the ratio of secondary phase and primary phase (RSP) and the potential ecological risk index. The results show that: (1) The fly ash is in good microstructure at small density, with rich contents of rapidly available potassium and phosphorus. (2) The total average value of the six heavy metal elements in fly ash is higher than the background value of soil environment in Ningxia, but less than the screening value of soil pollution risk of other agricultural land (the basic items). The times of out-of-limit is ranked as Pb, Cu, Cr, As, Cd and Ni in order. The available contents of the six heavy metals do not exceed the background value of soil environment in Ningxia and the screening value of soil pollution risk of other agricultural land. (3) According to the RAC assessment results, the ecological risk is high for As, medium and high for Cd, Cu and Ni, low for Cr and zero for Pb. Meanwhile, the heavy metal As is slightly polluting, while Pb, Cr, Ni, Cu and Cd are non-polluting in accordance with the RSP assessment results. Moreover, the results of potential ecological risk index method show that the total amount and effective RI index of the six elements in fly ash are at grade I, with slight ecological hazard. Especially, Cd is the main contributing element of ecological risk. Therefore, fly ash could be used as the cemented filling material in coal mines for large-scale resource utilization. |
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