煤中微量元素的环境效应

以华北某电厂燃煤为例,探讨了煤中微量元素的环境效应评价方法。通过电感耦合等离子体原子发射光谱(ICP-AES)等方法测定了电厂循环流化床炉原煤、飞灰、底灰中F,Pb,Hg,等11种微量元素的含量,通过淋滤实验测得了原煤及底灰中Pb、Hg、Cr等7种微量元素的淋出率,并测定了煤堆附近土壤中Cd、Hg、Cr等6种微量元素的含量,计算出了煤中微量元素对大气、水和土壤环境的污染因子。结果表明,燃煤中元素F、Hg、Se、Cl挥发性较强,燃煤中微量元素对大气环境的综合污染因子达3.5,属重污染。元素Hg、As的淋出率较高,原煤和底灰中微量元素对水环境的综合污染因子分别为0.71和0.88,污染程度属微污染。土壤对Cd、Hg、Pb等元素的富集程度很高,煤中微量元素对土壤环境的综合污染因子为0.98,属微污染。

Environmental Impact Assessment of Trace Elements in the Coal

Taking the coal of a power plant in North China as example,the environmental impact assessment method of trace elements in coal was studied. 11 trace elements of F,Pb,Hg in raw coal,fly ash,bottom ash of the CFB combustor in the power plant were determined by the method of ICP-AES. The leached rates of 7 trace elements of Pb,Hg,Cr in the coal and bottom ash were determined by leaching test. The contents of 6 trace elements of Cd,Hg,Cr in the soil near the coal dump were also tested. Then the atmospheric pollution index,water pollution index and soil pollution index were calculated. Results indicted that the volatility of the elements of F,Hg,Se and Cl in the coal are strong. The individual indices of the elements of F,Cr,As,Se, Mn and Be are greater than 1. The integrated pollution index of the trace elements in the coal on the atmospheric environment is 3.5 which belong to heavy pollution. The leaching rates of Hg and As in the coal and bottom ash are higher. The integrated pollution indices of trace element in the coal and the bottom ash on the water environment which are 0.71 and 0.88 respectively belong to unpolluted. The enrichment of the elements of Cd,Hg,Pb in the soil is quite great. The integrated pollution index of trace elements in the coal on the soil environment is 0.98 and belongs to unpolluted but was close to the lower limit of light pollution.