摘要
在小型熔融实验台上,将不同比例的SiO2与焚烧飞灰均匀混合进行熔融处理实验,系统地研究了SiO2掺入量对熔融试样的重金属分布、浸出毒性等方面的影响。结果表明,飞灰SiO2掺入量对焚烧飞灰熔融特性有显著影响,SiO2添加剂可有效控制焚烧飞灰重金属污染物。当Cr,SiO2掺入量为15%时,Cr的固溶率达到最高,为106.3%;对于Ni,Cu和As,当SiO2的掺入量低于15%时,有利于它们的固溶率提高,但SiO2掺入量超过15%时,3种重金属的固溶率与SiO2掺入量成反比。对于Cd、Pb、Zn,三者的挥发率均随SiO2的添加量增加而减少,但SiO2对Zn的挥发抑制作用较明显,而对Pb,Cd的挥发有较弱影响;SiO2掺入量对Hg的挥发几乎没有影响。当SiO2掺入量超过20%时,熔渣断面平整且结构致密,呈细条纹状,表面无任何孔隙。随着SiO2掺入量的增加,试样收缩率趋于线性增长,熔渣密度则缓慢减小,熔融体中重金属的浸出率呈减少趋势。
Mixed ash samples of fly ashes from MSW incinerator, which adding additives of SiO2 in different ratios, were carried out to determine melting treatment. Effects of the heavy metals distribution and leaching toxicity have been systematically studied. Experimental results indicate that the SiO2 content of fly ashes have a notable influence on melting characteristics. Adding SiO2 into fly ashes samples would effectively control the heavy metals contamination emission. For Cr, the ratio of fixation was up to the maximum 85.4% with the addition of additives about 15wt%. When adding below 15% would be of advantage to make more the heavy metals Ni, Cu, and As, stabilizing in slag. Whereas the amounts ofNi, Cu, and As, fixation in slag would decrease with the adding content of SiO2 increasing in fly ash. For Cd, Pb, and Zn, the amounts of evaporation reduce with the adding of SiO2 increasing. Adding SiO2 into fly ash would validly restrain the quantity of Zn evaporation, but it have a petty effect on the controlling for the evaporation of the Pb and Cd. The amounts of Hg volatilization would be immune from altering SiO2 content in fly ash. When adding above 20%, molten samples become full smooth, much compact in surface structure, while the sections of the molten samples have no apparent aperture. With the elevation of adding SiO2, the shrinkage mount up, but the density decrease slowly. The leaching rates of heavy metals decrease distinctly.
出处
《电站系统工程》
北大核心
2007年第5期17-20,共4页
Power System Engineering
基金
教育部高等学校博士点基金资助项目(20030286005)
江苏省建设系统科技计划资助项目(JS200311)
河南科技大学博士科研基金(09001135)
