粉煤灰中砷溶出特性及其与铁锰相关性分析  

Arsenic leaching characteristics and correlations with iron,manganese in fly ash from coal-fired power plants

作　　者：金毅[1] 苑春刚[1] 江万平[1] 齐立强[1] 赵毅[1] 

机构地区：[1]华北电力大学环境科学与工程学院,保定071003

出　　处：《环境化学》2013年第2期267-274,共8页Environmental Chemistry

基　　金：河北省自然科学基金(B2010001676);教育部新世纪优秀人才支持计划(NCET-10-0341);中央高校基本科研业务费专项资金资助

摘　　要：将不同燃煤电厂的粉煤灰分为0—2.5μm、2.5—10μm、10—60μm、60—100μm、100—200μm、>200μm不同粒径的样品,采用原子荧光光谱法测定了其中的总砷含量.粉煤灰对砷的富集效果与粒径呈明显的负相关.分别采用去离子水、醋酸、稀盐酸、盐酸羟胺、草酸铵-草酸和柠檬酸钠-连二亚硫酸钠为提取剂对不同粒径粉煤灰中的砷进行了提取.结果显示,去离子水可提取态砷占总砷含量的5.93%—18.70%,醋酸溶液提取砷占总砷的6.78%—16.91%,采用0.25 mol.L-1稀盐酸、0.6 mol.L-1稀盐酸、盐酸羟胺、草酸铵-草酸为提取剂可提取态砷占总砷的比例分别为18.1%—56.5%、28.2%—74.8%、43.4%—80.8%和39.1%—66.7%.盐酸羟胺对砷的提取效果最佳.采用稀盐酸、盐酸羟胺、草酸铵-草酸为提取剂时,可提取砷含量与铁、锰含量具有很好的线性相关性,同时,可提取砷占总砷含量的比例与铁、锰之间也存在显著线性相关性.Fly ash samples from three different coal-fired power plants were divided into sub-samples according to particle size（0—2.5 μm,2.5—10 μm,10—60 μm,60—100 μm,100—200 μm,200 μm）.Total concentrations of arsenic in the samples were determined by atomic fluorescence spectrometry.It was found that the total arsenic in fly ash was negatively correlated with particle size.Arsenic in the fly ash samples with different particle size（200 μm,100—200 μm,60 μm） was extracted respectively by deionized water（H2O）,acetic acid（CH3COOH）,diluted hydrochloric acid（HCl）,hydroxylammonium chloride（NH2OH · HCl）,oxalate-ammonium oxalate solution（C2H2O4-（NH4）2C2O4）,and sodium citrate-sodium hydrosulfite solution（Na3C6H5O7-Na2S2O4）.The results revealed that water soluble arsenic accounted for 5.93%—18.7% of total arsenic.Carbonate arsenic extracted by acetic acid accounted for 6.78%—16.91% of total arsenic.Arsenic concentrations extracted by 0.25 mol · L-1 HCl,0.6 mol · L-1 HCl,NH2OH · HCl,C2H2O4-（NH4）2C2O4 accounted for 18.1%—56.5%,28.2%—74.8%,43.4%—80.8% and 39.1%—66.7% of the total amount,respectively.NH2OH · HCl was the most effective reagent for arsenic leaching from fly ash in our experiment.The concentration of extractable arsenic had significant linear correlation with the concentration of Fe and Mn in fly ash.

关 键 词：粉煤灰 砷 溶出特性 铁锰 相关性 

分 类 号：X773[环境科学与工程—环境工程]