焚烧飞灰磷灰石药剂稳定化技术研究

对垃圾焚烧飞灰的全组分和浸出特性进行了分析,表明焚烧飞灰含有多种重金属,其中Pb、Zn和Cd等的浸出毒性分别达到11.8、164.9和31.2mg/L,远高于危险废物浸出毒性标准.实验选择新型无机稳定化药剂———磷灰石对焚烧飞灰的重金属稳定化效果进行研究,结果表明:在磷灰石投加量7%时,处理后焚烧飞灰的重金属浸出毒性(部分样品除镉外)均达到了危险废物填埋入场控制限值;焚烧飞灰的稳定化效果与磷灰石的粒径有关,当其粒径为200目时能够取得较好的稳定化效果;稳定化产物在养护时间1d后,其重金属浸出浓度不再改变;实验证明在pH 3～11范围内稳定化产物都具有较好的稳定化效果,减少了稳定化产物在环境条件下的二次污染的风险.

Chemical Stabilization Technology in Treating with Flyash Using Apatite

Toxicity leaching characteristics and chemical compositions of sample flyash collected from municipal solid waste incinerator was analyzed, it was clear that different heavy metals were contained in flyash and the heavy metal leaching concentration for Pb, Zn, Cd was 11.8, 164.9 and 31.2 mg/L respectively which was much higher than that in Hazardous Waste Toxicity Leaching Standards. A new kind of inorganic chemical agent apatite was chosen to treat with this kind of incineration flyash, the results indicate that the heavy metals (not including Cd in some samples) in the treated flyash using apatite at dosage 7% can reach the landfilling standards for hazardous waste, and the treated flyash can have better stabilization when the size of apatite was 74 microm, and the heavy metal leaching concentration of the treated flyash keep stable at a curing time of 1 day, and it can keep stabilization with a broader pH value of 3 to 11. Thus the risk of secondary pollution for the treated flyash was reduced dramatically when the environment conditions change.