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研究报告

摘要：从珠三角地区2家典型垃圾焚烧厂采集飞灰，通过分析飞灰中金属及二英异构体的组成和分布特性，提出了水洗球磨法处理飞灰的新工艺.结果表明，飞灰中细颗粒物所占的比重大，80%以上的颗粒集中在2~100 μm粒径之间，二英主要集中的粒径范围是30~53 μm.飞灰中的二英包括多氯二苯并呋喃类（PCDFs）和多氯二苯并对二英类（PCDDs）两大类，二英的17种主要异构体中含量最大的是OCDD，毒性当量浓度最大的物质为2，3，4，7，8-PeCDF.水洗后钾盐钠盐大量溶出，而二英是水难溶性物质，水洗后98%以上仍在固相中.使用球磨法降解飞灰水洗渣中的二英可以实现较好的降解率，特别是当使用双金属球磨法时，降解率可以达到93.20%.球磨过程中PCDDs类物质优先降解，且PCDFs类物质可能会转化成PCDDs类物质.当球磨反应进行到20 h时，球磨时间过长造成了二英的二次生成.

Abstract：Samples were taken from different types of typical waste incineration plants in the Pearl River Delta. By analyzing the characteristics of composition and distribution of metals and dioxin congeners in fly ash, water-ball milling was proposed to handle fly ash. The results showed that small particles had a higher proportion in fly ash and more than 80% of particles were in the range of 2~100 μm. Dioxin was mainly concentrated in the range of 30~53 μm. In fly ash, dioxin included PCDFs and PCDDs. Dioxin congeners mainly included 17 categories, within which OCDD had the maximum concentration, and the most I-TEQ substance was 2,3,4,7,8-PeCDF. Washing could promote dissolution of potassium salt and sodium salt. However, more than 98% of dioxins remained in the solid phase after washing as they were insoluble. Ball-milling could achieve better degradation rate for dioxin in washing slag of fly ash. Particularly, when the method of bimetallic ball-milling was used, the degradation rate of dioxin could reach 93.02%. In the process of reaction, the degradation of PCDDs was prior to PCDFs, and PCDFs may transform to PCDDs. When the reaction time reached 20 h, the secondary formation of dioxin may occur.