摘要
为了响应包头市“无废城市”建设及对矿坑环境整治的要求,拟用典型工业固体废物(粉煤灰)填埋对矿坑进行生态治理,但粉煤灰填埋长期的环境行为对矿坑土及地下水是否造成污染尚未可知,通过冻融循环—干湿交替的室内模拟方法和Hydrus-1D模型、溶质运移模型预测的方法,对粉煤灰填埋于矿坑后重金属的长期环境行为进行了研究。结果表明:粉煤灰在填埋5年后,重金属Cd、Pb、Cr、Cu含量分别降低了0.4、3.23、16.67、12.93 mg/kg,而矿坑土Cd、Pb、Cr、Cu含量分别增加了0.04、9.27、8.3、3.3 mg/kg;同时形态分析表明,粉煤灰中Cd、Cr以有机结合态为主,Pb以残渣态为主,重金属形态由铁锰氧化态和有机结合态向可交换态和碳酸盐结合态转化,说明重金属形态由稳定态向易迁移态转化。模拟结果表明,粉煤灰填埋于矿坑5年后,重金属元素有向周边环境迁移转化的趋势,因此在填埋过程中在矿坑底部做好防渗层,从而降低四种重金属Cr、Cd、Cu、Pb对矿坑土壤及地下水环境的污染风险,其含量远低于《土壤环境质量建设用地土壤风险管控标准》(GB 36600—2018)中筛选值及所影响区域的地下水中污染物标准,此状况下粉煤灰符合填埋标准,可以进行填埋。该研究可为固废在矿坑生态化利用工程应用提供科学依据和参考。
In order to respond to the construction of "waste-free city" in Baotou city and the requirements of mine environmental improvement,typical industrial solid waste(fly ash) is planned to be landfilled for ecological remediation of the mine.However,it is unknown whether the long-term environmental behavior of fly ash landfill will cause pollution to the mine soil and groundwater,the long-term environmental behavior of heavy metals after fly ash was landfilled in mine pit was studied by the indoor simulation method of freeze-thaw cycles-dry-wet,Hydrus-1D model and solute transport model prediction.The results showed that:After 5 years of landfill,the contents of heavy metals Cd,Pb,Cr and Cu decreased by 0.4,3.23,16.67 and 12.93 mg/kg respectively,while the contents of Cd,Pb,Cr,and Cu in mine soil increased by,0.04,9.27,8.3 and 3.3 mg/kg,respectively.At the same time,the speciation analysis showed that Cd and Cr in fly ash are mainly organic-matter bound,Pb is mainly in the residual,and the heavy metal forms changed from Fe-Mn oxides-bound and organic matter-bound to solube-exchangeable and carbonate-bound,which indicated that the heavy metal forms are transformed from stable state to easy migration state.The simulation results showed that five years after the fly ash is landfilled in the mine pit,the heavy metal elements have a tendency to migrate and transform to the surrounding environment.Therefore,in the process of landfill,an anti-seepage layer is laid at the bottom of the mine pit.The four heavy metals(Cr,Cd,Cu,and Pb)did not pose the risk of heavy metal migration to the mine pit soil and groundwater environment,its content is far lower than the screening value in the "Soil Risk Control Standard for Construction Land with Soil Environmental Quality"(GB36600-2018)and the pollutants in the groundwater in the affected area are lower than the Class Ⅳ groundwater standard.Under this condition,the fly ash meets the landfill standard and can be landfilled.This study can provide scientific basis and reference for the
作者
许欣
武小燕
陈敏洁
曹丹
郑春丽
XU Xin;WU Xiaoyan;CHEN Minjie;CAO Dan;ZHENG Chunli(School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China;School of Life Science and Technology,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China)
出处
《有色金属（矿山部分）》
2023年第1期73-81,共9页
NONFERROUS METALS(Mining Section）
基金
国家重点研发计划项目(2018YFC1802904)
内蒙古自然科学基金项目(2021MS05033)
内蒙古科技成果转化专项项目(2019CG062)。
关键词
粉煤灰
填埋
重金属
环境行为
生态化利用
fly ash
landfill
heavy metals
environmental behavior
ecological utilization
