垃圾焚烧飞灰熔融过程中重金属分离效果影响因素研究

采用重庆同兴垃圾焚烧发电厂产生的焚烧飞灰,在感应炉上进行熔融处理实验研究,探讨了熔融温度、熔融时间、碱度等因素对熔融过程中重金属分离效果的影响.结果表明,重金属的挥发率按其熔沸点高低区分明显,Pb、Zn和Cd的挥发率较高,分别为80%、60%和95%左右;Cr、Mn的挥发率均低于10%.随着熔融时间、熔融温度和碱度的增加,Pb、Zn、Cd、Mn、Cr的挥发率变化趋势不明显;铁浴熔融方式可进一步促进Zn、Pb、Hg的挥发,有利于Cr、Cu从熔渣中分离出来,与生铁形成合金.对熔渣的浸出毒性测试结果表明,重金属元素的浸出毒性均可达标(GB5085.3-1996).

Impacts on the separation of heavy metals in municipal solid waste(MSW) incineration fly ash melting process

Melting experiments were carried out to investigate the impacts on the separation of heavy metals in melting process for MSWI fly ash, which was sampled from Tongxing MSW incineration plant in Chongqing. The impact parameters included heating temperature, heating time and basicity. The results indicated that the evaporation of heavy metals had an obvious distribution along with their different melting and boiling point. The evaporation rate of Pb, Zn and Cd is separately high to about 80%,60% and 95%, while the evaporation rate of Cr and Mn are both below 10%. And the evaporation of Pb, Zn,Cd, Mn and Cr has a very weak change along with the variation of heating temperature, heating time and bisicity. The melting process with iron-bath can increase the evaporation of Zn, Pb and Hg, and promote the distribution ratio of Cr and Cu in iron phase. The leaching toxicity of molten slag were tested, and the leaching toxicity of all the metals can reach the standard.