成分对垃圾飞灰熔融过程重金属迁移的影响

Heavy metal migration during vitrification of municipal solid waste incinerator fly ash

熔融处理可以有效控制垃圾焚烧飞灰中的重金属污染 ,飞灰成分对重金属的迁移特性有重要影响 ,研究了飞灰成分和碱度对 6种重金属迁移固化的影响规律。在自行设计的小型实验台上开展飞灰熔融实验 ,飞灰碱度在 0 .6～4 .6范围内变化。为评价多种重金属综合固化效果提出一个简明的评价模型。在 14 6 0℃、空气气氛下熔融处理时 ,加入Ca O后除了 Cd外各种重金属的固化率均下降 ,而加入 Si O2后多数金属固化率增加。存在一个临界碱度值可以实现重金属的最佳固化 ,实验得到的临界碱度在 1.

Fly ash from municipal solid waste incinerators contains various pollutants including potentially hazardous heavy metals. Vitrification is an effective technique for stabilizing the heavy metals. The influence of ash composition on the migration characteristics of six heavy metals was studied in experiments performed in a lab-scale furnace with an air atmosphere at 1 460 ℃ with the basicity of the CaO/SiO_2 fly ash varied from 0.6 to 4.6. A model was developed to evaluate the binding efficiency of the heavy metals. The results show that an increased CaO content results in decreased binding of the heavy metals except Cd. Increase of the SiO_2 content has the opposite effect. A critical basicity gives the highest binding efficiency of heavy metals. For the fly ash used in these tests, the critical basicity is about 1.0.