不同处理方法对硅灰稳固化垃圾焚烧飞灰重金属的影响

向飞灰中添加硅灰与一定比例的去离子水，混合均匀后分别进行自然养护、蒸汽养护和中温热处理.研究了自然养护和蒸汽养护条件下硅灰不同添加量对垃圾焚烧飞灰浸出毒性的影响，考察了蒸汽养护样与中温热处理样的重金属化学形态分布、晶体结构和微观形貌变化.结果表明：自然养护和蒸汽养护条件下，随着硅灰添加量由0%升至10%，飞灰中Pb、Cd、Cr和Cu的浸出浓度均随之降低.硅灰添加量为10%时，硅灰蒸汽养护样中Pb、Cd、Cr和Cu的浸出浓度略低于硅灰自然养护样，金属化学形态分布相比原灰变化较小；硅灰中温热处理对飞灰中Pb、Cd、Cu和Zn处理最为彻底，4种金属残渣态占比相比原灰分别从原灰的37.12%、11.82%、44.30%和51.94%升高至84.75%、75.49%、77.20%和67.40%，酸溶态分别由原灰的3.99%、54.92%、6.56%和10.49%降低至0.44%、9.37%、2.72%和3.59%.

Effects of different treatment methods on the stabilization of heavy metals in municipal solid waste incineration fly ash using silica fume

After mixing municipal solid waste incineration fly ash (MSWIFA) with silica fume and a certain proportion of deionized water, natural curing, steam curing and thermal treatment were performed respectively to stabilize heavy metals. The effects of additive amounts of silica fume on the leaching of critical heavy metals in MSWIFA with natural curing and steam curing were studied. Specification distribution of heavy metals, crystal structures and microstructures of steam curing samples and thermal treatment samples were also investigated. The results showed that the leaching concentrations of Pb, Cd, Cr and Cu gradually decreased with the addition of silica fume from 0% to 10% while using natural curing and steam curing. When adding 10% silica fume, the leaching concentration of Pb, Cd, Cr and Cu for natural curing samples were slightly higher than that for steam curing samples, in which specification distribution of heavy metals did not show significant change as compared with that in raw fly ash. Highly effective heavy metal stabilization of thermal treatment for Pb, Cd, Cu and Zn could be achieved, proven by leaching test results and specification distribution of heavy metals. The ratios of residue state of Pb, Cd, Cu and Zn in fly ash after thermal treatments increased from 37.12%, 11.82%, 44.30% and 51.94% to 84.75%, 75.49%, 77.20% and 67.40%, respectively, while the ratios of acid soluble state decreased from 3.99%, 54.92%, 6.56% and 10.49% to 0.44%, 9.37%, 2.72% and 3.59%, respectively.