生态水泥中SiO2掺量对焚烧飞灰中重金属固溶特性的影响

按不同SiO2掺量(质量分数)进行垃圾焚烧飞灰的水泥固化试验,研究了SiO2掺量对熟料试样的重金属分布、浸出毒性的影响。结果表明,SiO2掺量低于16%时,提高掺量有利于增加熟料中Cr、Ni、Cu、As固溶率;但SiO2掺量超过16%后,重金属固溶率与其成反比。Cd、Pb、Zn的挥发率随SiO2掺量增加而减少,掺加SiO2能明显抑制Zn的挥发,但基本不影响Hg的挥发。SiO2掺量增加后熟料结构进一步致密化,重金属浸出量减少。

Effect of SiO2 Mixing Ratio on Solid Solubility of Heavy Metal in MSWI Fly Ashes in Ecological Cement

Cement solidifications test for fly ashes from MSW incinerator, which mixing SiO2 in different ratios, were carried out. Effects of SiO2 mixing ratios on heavy metals distribution and leaching toxicity in clinkers were studied. Experimental results indicate that increasing SiO2 mixing ratio would be beneficial to make more Cr, Ni, Cu and As stabilizing in clinker when mixing SiO2 below 16%. Whereas the solid solubility of Cr, Ni, Cu and As would decrease with the mixing ratio of SiO2 increases (above 16%). For Cd, Pb and Zn, the amounts of evaporation reduce with the mixing ratio of SiO2 increases. Adding SiO2 mixing ratio would validly restrain the evaporation quantity of Zn, but the volatilization amount of Hg would be immune from it. With the increase of mixing SiO2, the clinker samples become much compact in microstructure, and the leaching amounts of heavy metals decrease distinctly.