不同粒径垃圾焚烧飞灰中重金属富集特性表征

Heavy metal enrichment in municipal solid waste incineration fly ash with various size ranges

针对杭州市生活垃圾焚烧飞灰按粒径级别进行其重金属特性表征,主要展开飞灰组成元素和矿物成分、重金属含量分布、以及重金属与飞灰颗粒的微观结合行为等研究.结果表明,"SiO2-CaO-Al2O3-金属氧化物"体系构成了重金属的富集载体;Zn、Pb、Cu、Mn、Ni、Cr、Sb等重金属在75—125μm飞灰颗粒中的占有率最高,达52%;Zn、Cu、Cr随着粒径减小其含量显著增加,其它重金属未见此趋势;通过SEM-EDX对飞灰颗粒表面和断面进行扫描电镜观察和面、线扫描元素能谱分析,在飞灰断面发现了更多类型、更密集的重金属分布.通过结合XRF、ICP-MS、SEM-EDX等仪器手段分析飞灰中重金属富集特性,深入探索重金属在飞灰颗粒中富集特征.

Fly ash from a Hangzhou incinerator was characterized on the basis of the particle size distribution. Major elements, heavy metal distribution, and binding states of heavy metals with fly ash particles were studied in this paper. It was found that SiO2-CaO-A12 03-metal-oxide was the carrier of heavy metals in fly ash. The contribution of Zn, Pb, Cu, Mn, Ni, Cr, Sb in 75--125 ~m of the fly ash fraction is the highest, which reached about 52%. Zn, Cu and Cr contents increased with decreasing size of fly ash particles, but other heavy metals showed little increase. More heaW metals and higher distributions were detected on the crossing- section area of fly ash particles than their surface area. Our results suggest that the comprehensive method of applying XRF, ICP-MS, and SEM-EDX to analyze heavy metals in fly ash can provide better and deeper understanding on heavy metal distributions.