城市垃圾焚烧飞灰特性及水泥固化试验研究

试验分析了重庆市某城市垃圾焚烧发电厂飞灰的化学成分，研究了原飞灰的浸出毒性，考察了水泥对原飞灰和酸洗预处理飞灰中重金属的固化效果. 结果表明:飞灰中重金属Pb和Zn的浸出质量浓度均超过《危险废物浸出毒性鉴别标准》(GB5085.3-2007)，因而被认为是危险废物，必须对之进行稳定化处理；酸洗预处理飞灰固化试块的抗压强度得到了一定程度的提高，其重金属Pb和Zn的浸出毒性均较相同配比、相同养护时间的原飞灰固化试块有明显降低；酸洗预处理飞灰固化试块抗压强度随掺入飞灰比例的降低和养护时间的延长而加大，在养护28 d时其抗压强度最高，达4.25 MPa；酸洗预处理飞灰固化试块在养护28 d时，其重金属Pb和Zn的浸出质量浓度分别比原飞灰所制固化试块降低了10.6%～59.0%和7.4%～73.7%. 

Experimental Study on Properties and Cement Solidification of Municipal Solid Waste Incineration Fly Ash

Fly ash was sampled from a certain municipal solid waste incineration (MSWI) power plant in Chongqing City. The chemical compositions were analyzed and the leaching properties of original MSWI fly ash were studied. The solidification effect of cement on heavy metals in original MSWI fly ash and in the MSWI fly ash washed withnitric acid solution was investigated. The results show that it is necessary tosolidificate the heavy metals in the original MSWI fly ash since uncontrolled leaching of its heavy metals constituent, especially Pb and Zn, would be a potential hazard. The compression strength of fly ash test block can be improved in a certain degree after being pretreated by washing it with nitric acid solution.The leaching toxicity of Pb and Zn of the pretreated fly ash test block is lower than the original one at the same proportion and the same curing time. The compressive strength of the pretreated fly ash test block is elevated with the decreasing of the ratio of fly ash and the extending of curing time, it reaches its maximum 4.25 MPa after 28-day conservation period. The leaching toxicity of Pb and Zn of the pretreated fly ash test block reduces by 10.6%～59.0% and 7.4%～73.7%, respectively, compared with original one after 28-day conservation period.