可溶性磷酸盐处理焚烧飞灰的稳定化技术

Heavy Metal Stabilization in Municipal Solid Waste Incineration Fly Ash Using Soluble Phosphate

对垃圾焚烧飞灰的基本物化性质进行了分析,表明焚烧飞灰的主要元素以Ca、Cl、K、S、Si等为主,另外还含有相当数量的重金属如Pb、Zn、Cu、Mn和Cr等,且Pb、Cu、Zn、Cd等重金属的浸出毒性远高于危险废物浸出毒性标准.研究采用可溶性磷酸盐对焚烧飞灰进行稳定化处理,分别考察了磷酸盐投加量、养护时间和pH值等因素对稳定化产物的影响.结果表明:磷酸盐可以对焚烧飞灰取得很好地稳定化效果,当磷酸盐投加量为3%时,飞灰中重金属Pb、Cd和Zn的浸出浓度能够分别降低97·5%、91·6%和95·5%;养护时间对稳定化产物稳定性的影响不大;稳定化产物能够在相当宽泛的pH范围内保持稳定,其长期稳定化效果很明显.

The physico-chemical characteristics of municipal solid waste incineration fly ashes was analyzed. It indicated that the main elements of fly ashes are Ca,Cl,K,S and Si, and many heavy metals such as Pb,Zn,Cu,Mn and Cr can be found in fly ashes, and the heavy metal leaching toxicity such as Pb,Cu,Zn and Cd is much higher than the standards. A new kind of stabilization agent-soluble phosphate is chosen to treat with fly ash, different influence factors including agent dosage, curing time and pH are taken into consideration to test its stabilization for the stabilized fly ash. The experimental results indicate that fly ash treated with soluble phosphate can have excellent stabilization effect, and the leaching toxicity for Pb,Cd and Zn can be reduced by 97.5%,91.6% and 95.5% at a phosphate dosage of 3%; curing time can not influence its stabilization; and, stabilized fly ash using soluble phosphate can keep long-term stabilization at a broad pH value.