垃圾焚烧飞灰中重金属的分布规律及浸出特性

文章研究了上海某垃圾焚烧厂不同粒径飞灰中重金属的分布特性。结果表明,大部分飞灰聚集在38～280μm,其中在38～53μm飞灰约占总量的50%。飞灰中重金属在不同粒径中的含量分布规律均为:Pb>Zn>Cu>Cr>Cd>Ni;除Ni和Cr外,重金属Zn、Cd、Cu和Pb都普遍表现出向小颗粒富集的趋势。重金属在不同粒径中的浸出量均为:Pb>Zn>Cr>Ni>Cu>Cd;Cr、Ni、Cu和Cd的浸出量随飞灰粒径的减小呈增加趋势,而Zn在106～280μm和Pb在75～106μm处的浸出量都经历了一个陡增过程。不同重金属的主要化学形态各不相同,除Ni和Cr外,其它重金属的主要形态都呈不稳定性。随着飞灰粒径的减小,碳酸盐结合态的Cd、Pb、Zn、Cu和铁锰氧化物结合态的Pb、Zn、Cu的量逐渐增加;残留态的Zn和有机结合态的Cu则不增反减;Ni和Cr的各形态分布规律不明显。

Distribution and Leaching Characteristics of Heavy Metals in MSWI Fly Ash

Distribution of heavy metals in municipal solid waste incinerator(MSWI)fly ash was investigated by means of particle size and leaching procedures.Results showed that most of fly ash was accumulated in fractions with particle size of 38～280μm and fractions of 38～53μm accounted for about 50%.Besides Ni and Cr,other metals including Zn,Cd,Cu and Pb were mainly accumulated in fine fractions.The amount of Cr,Ni,Cu and Cd that leached out from fly ash samples increased with the decrease of particle size of fractions,while amount of Zn and Pb that leached out presented a rapid increase in 106～280μm and 75～106μm.Chemical speciation distribution of heavy metals was distinctly different according to results from sequential extraction procedure,and the most heavy metals were presented in the unstable speciation except of Ni and Cr.