Stabilization of heavy metals in hazardous waste incineration fly ash
危险废物焚烧飞灰中重金属的稳定化处理

Stabilization of heavy metals in hazardous waste incineration fly ash from a hazardous waste incineration plant in Shanghai by using four different kinds of chemical agents i.e.,Na2S,FeSO4,Na3PO4 and Na3C3N3S3 were investigated in this study.And the treated fly ash using Na3C3N3S3 was analyzed by using XRD,FTIR,scanning electron microscope and sequential chemical extraction.The result of toxicity characteristic leaching procedure indicated that Na3C3N3S3 had an excellent stabilization to heavy metals,such as Cr,Pb,Zn,whereas the effect of Na3PO4 could be ignored for Cr.The SEM,XRD and IR results show that surface structure become stable,and the structure of the product was amorphous under atmospheric conditions.The fractionation analysis revealed that the distributions of heavy metals significantly changed after treatment.The proportion of exchangeable decreased and oxidizable increased.Therefore the leaching toxicity of fly ash could be gradually reduced.