垃圾焚烧炉飞灰熔融特性及重金属的分布
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摘要: 对垃圾焚烧炉飞灰进行了差热分析及熔融实验，探讨了不同熔融温度对试样的灼烧减量及重金属分布特性的影响。结果表明，飞灰试样在1132℃时熔融，在1252℃～1290℃发生二次熔融。灼烧减量在1200℃达到最低值27.5％； Cr、Ni、Cu在熔融体中的固溶率随着沸点的升高而依次升高。重金属Pb、Cd、As、Hg挥发率均超过95％，挥发性依次为Pb>Cd>As>Hg；飞灰中Zn的氧化物熔融后转化为Zn2SiO4、ZnSiO3和ZnAl2O4等不易挥发的化合物，且Zn在1200℃时挥发率最低仅有66.7％。Abstract: Fly ashes from municipal solid waste (MSW) incinerator were used to determine melting point and to perform differential thermal analysis. The weight loss and heavy metals distribution during calcination in air at different temperatures were discussed. It indicates that the minimum of weight loss is up to 27.5%. Melting reaction of fly ashes initially occurs at 1132℃ and exhibits the second melting reaction at 1252℃～1290℃. The proportions of Cr, Ni and Cu in melted samples increase with the elevation of their melting point and boiling point. The amounts of evaporation are above 95% for Pb, Cd, As, and Hg. The quantities of evaporation is in sequence of Pb>Cd>As>Hg. Zinc in fly ashes exists in the form of ZnO, which forms the nonvolatile compounds such as Zn2SiO4, ZnSiO3, and ZnAl2O4. The minimum rate of Zn evaporation in fly ashes is 66.7% at 1200℃.
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Key words:
- MSW incineration /
- fly ash /
- melting /
- heavy metals
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