摘要
采用EPA Method 3051和微波消解以及模拟中性和酸性降雨及垃圾渗滤液对燃煤电厂F类3个等级的粉煤灰和渣开展浸泡实验,并使用电感耦合等离子体质谱法(ICP-MS)测定了其重金属的含量,分析粉煤灰和渣中重金属的分布特征及不同酸碱度下的浸出毒性.结果表明,3个等级的灰中Cr、Mn、Ni、Cu、Zn和Pb的平均含量分别为35.75、148.06、19.64、17.95、32.95和14.95μg.g-1,都低于天津地区土壤环境背景值,但Cd的含量(0.182μg.g-1)远超过环境背景值.重金属在3个级别灰中的分布没有明显差异,但都比渣中的含量高,而Mn则相反,其含量呈现明显的分布特征(Ⅰ级灰<Ⅱ级灰<Ⅲ级灰<渣),随着粒径增大,Mn的含量在增加.模拟中性和酸性降雨对灰渣的浸泡实验表明,Mn、Ni、Cu、Zn和Pb浸出效率都比较低(<0.11%),Cr和Cd则有较高的浸出率,在模拟垃圾渗滤液浸泡实验中重金属的浸出率明显上升,Cd上升最为明显,其在Ⅰ级、Ⅱ级、Ⅲ级灰及渣中的浸出率分别达到26.6%、17.7%、14.4%和8.3%.若采用湿式除灰渣的处理方式将会对Cd产生淋溶作用,存在一定的环境风险.
Three levels of class F fly ash and slag of thermal power plant were digested with EPA Method 3051 and microwave,and extracted with three solutions of different pH to simulate the landfill leachate,the neutral and acid rain.The contents of heavy metals（Cr,Mn,Ni,Cu,Zn,Cd and Pb） were determined by the inductively coupled plasma mass spectrometry（ICP-MS） to analyze their distribution characteristics and leaching toxicity.The results showed that the mean contents of Cr,Mn,Ni,Cu,Zn and Pb in three levels of fly ash were 35.75,148.06,19.64,17.95,32.95 and 14.95 μg·g-1,respectively,which were lower than Tianjin soil environmental background value.However,Cd content（0.182 μg·g-1） exceeded the background value.There were no significant difference in the distribution of three levels of fly ash,but the concentrations were higher than those of heavy metals in slag.On the contrary,the content of Mn showed the obvious distribution characteristics（fly ash Ⅰ fly ash Ⅱ fly ash Ⅲ slag）,and it increased as the particle size increased.Simulation results of neutral and acid rain on the fly ash and slag extraction showed that extractability of Mn,Ni,Cu,Zn and Pb were quite low（0.11%）,but Cr and Cd showed higher extractability.In the simulation experiment of landfill leachate extraction,the extractability of Cd increased significantly,the leaching rate of Cd in fly ash Ⅰ,Ⅱ,Ⅲ and slag were 26.6%,17.7%,14.4% and 8.3%,respectively.The wet ash and slag removal can induce the leaching of Cd,which had some environmental risks.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第6期1831-1836,共6页
Environmental Science
基金
天津市自然科学基金项目(10JCZDJC24500)
天津市高等学校科技发展基金计划项目(20080514)
关键词
粉煤灰
重金属
分布特征
模拟雨水
浸出
fly ash
heavy metals
distribution characteristics
simulated rain
leaching
