城市垃圾焚烧飞灰的水洗脱氯与水泥固化技术

Water-washing Dechlorination and Cement Solidification of Municipal Solid Wastes Incineration Fly Ash

利用水洗脱氯和水泥固化对垃圾焚烧飞灰进行固化/稳定化处理,研究了液固比对焚烧飞灰中氯和重金属的脱除效果的影响,以及水泥添加量和养护时间对固化体密度、抗压强度和重金属浸出毒性的影响。结果表明:水洗过程对氯离子的脱除率为60.11%~74.64%,当液固比L/S=20 mL/g时,氯离子的脱除率达到最高的74.64%,但重金属Cr、Cu、Ni和Zn在水洗过程的脱除率都小于2%。随着水泥添加量和养护时间的增加,固化体密度和抗压强度呈逐渐增大趋势。当水洗焚烧飞灰含量为10%~70%时,固化体中重金属Cr、Cu、Ni和Zn的浸出浓度远低于GB 5085.3—2007规定的浸出阈值。

The water-washing dechlorination and cement solidification technology were used for the stabilization/solidification of municipal solid waste incineration fly ash.Effects of liquid-to-solid on the removal of chlorides and heavy metals were analyzed.Besides,the effects of cement addition on the density,compressive strength and leaching concenration of heavy mentals of solidified body were systematically studied.The results demonstrate that the removal rates of chlorides are 60.11%~74.64%during the processes of water-washing.The removal rate of chlorides reaches the maximum value of 74.64%when L/S was 20 mL/g,while those of heavy metals Cr,Cu,Ni,and Zn are below 2%.The density and compressive strenth of solidified body increase with the increase of cement addition.When the content of municipal solid waste incineration fly ash is ranged from 10%to 70%,the leaching concentrations of heavy metals Cr,Cu,Ni,and Zn are much lower than the limits suggested by China Standard of GB 5085.3—2007.