不同粒径垃圾焚烧飞灰金属形态分布比较研究

Comparative study on metal speciation distributions in MSWI fly ash with various particle sizes

研究了华南地区某垃圾焚烧厂的除尘器飞灰的化学组成和粒径分布,并采用分级提取法对不同粒径飞灰中的重金属化学形态进行了研究。同时比较了华南、华东、西南地区以及台湾地区垃圾焚烧飞灰的筛下累积分布和不同粒径飞灰中各重金属组成。结果表明,飞灰的组要成分为:CaO、SiO2和SO3等;各地区75%的飞灰粒径都主要集中在38.5～75μm。华南地区各粒径飞灰中挥发性金属(Zn和Pb)含量明显高于其他金属。除Ni和Cr外,Cu、Zn、Pb和Cd含量随粒径减小呈先减少后增大的趋势。华南地区Cu、Zn、Ni、Cr、Pb和Cd的含量均高于其他地区(台湾地区除外)。Cu、Zn和Cd的弱酸提取态和可还原态含量较高。高于40%的水溶态Pb表明其对环境有较大潜在危害;40%Ni和Cr主要以残渣态存在,对环境的潜在影响较小。

The chemical composition and distribution of particle size in municipal solid waste incinerator（MSWI） fly ash of South China were analyzed.The heavy metal contents and speciation with various particle sizes were analyzed by sequential chemical extraction procedure.The comparison was conducted to evaluate metal speciation distributions and particle size cumulative distribution with various particle sizes in different areas including South China,East China,Southwest China and Taiwan areas.The results showed that the main compounds were CaO,SiO2,SO3 etc.75% of fly ash particles were in the range of 38.5~75 μm.The concentrations of volatile metals Zn and Pb were larger than other metals.Concentrations of Cu,Zn,Pb and Cd,except Ni and Cr,decreased firstly and then increased with the decrease of particle sizes.It was also found that the weak acid soluble fractions and reducible fractions of Cu,Zn and Cd were relatively high.Up to 40% of Pb was mainly occurred as water soluble fraction,which had more potential risk to the environment.Over 40% of Ni and Cr took up as residue fraction with smaller potential risk impact on the environment.