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

以上海市某危险废物焚烧厂飞灰为研究对象,采用Na2S、FeSO4、Na3PO4、和Na3C3N3S34种不同类型化学稳定药剂对飞灰进行了稳定化处理,并应用XRD、IR、SEM和连续化学提取法等仪器和手段对Na3C3N3S3处理焚烧飞灰的产物进行分析研究。研究结果表明,Na3C3N3S3对飞灰中的重金属Cr、Pb、Zn的稳定效果最好,Na3PO4对Cr无明显稳定效果。稳定后产物表面变得致密化,Na3C3N3S3与重金属离子生成的沉淀物干燥后无明显晶型存在。经稳定处理后飞灰中的重金属形态由弱酸提取态转化为可氧化态,减少了飞灰中重金属的浸出毒性。

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.