火电厂飞灰中砷、硒的溶解特性及其与酸雨的相互关系

Solving Characteristics of Arsenic and Selenium in Fly Ash of Coal-Fired Power Plants and Interaction Beween Fly Ash and Acid Precipitation

本文研究了我国五个火电厂的飞灰、灰水及灰水塘底泥中的砷、硒。分析结果表明:飞灰中砷含量0.70—11.72 mg/kg,平均为5.80mg/kg,硒含量0.45—5.92mg/kg,平均值2.57mg/kg。灰水中砷、硒含量分别为2.01和0.70 mg/l;灰水塘泥中砷含量高达17.01mg/kg,硒含量高达2.01mg/kg。六种深提剂对飞灰中砷、硒的深解能力次序为:0.07MHCl>B溶液(pH3.5)>A溶液(pH5.5)>>0.5M乙酸>碱性溶液(pH8.5)>蒸馏水。溶提剂酸度愈高,对飞灰中砷、硒的溶解率也愈高。模拟酸雨A(pH5.5)对飞灰中砷、硒的平均溶解率分别为41.94 ％和57.97％;模拟酸雨B(pH3.5)则分别是63.50％和70.56％。酸雨对飞灰中砷、硒的溶解及其污染起着很大作用。

In this paper, we studied arsenic and selenium in fly ash, ash-washing water and sediment in ash water pond of five coal-fired power plants in China. The research results show that: the content of As in fly ash ranges 0.70-11.72 mg/kg (5.80mg/kg in average) and Se 0.45--5.92mg/kg (2.75mg/kg in average); the content of As in ash-washing water is 2.01mg/L and Se 0.70mg/L. The content of As in sediment of ash water pond is as high as 17.01mg/kg and Se 2.01mg/kg. Solubility sequence of As and Se of fly ash in six solvents is: 0.07MHCL>solution B(pH3.5)> solution A(pH5.5) >>0.5M acetic acid >alkaline solulion (pH8.5) >distilled water. The higher the acidity of solvent, the higher the solubility of As and Se in it. Solubility percentages of As and Se of fly ash are 41.97% respectively in simulative acid precipitation (pH5.5) , 63.50% and 70.56% in simulative acid rain (pH3.5). Acid precipitation even greatly effects the solution from As and Se in coal-fired fly ash.