Formation mechanism and influencing factors of dioxins during incineration of mineralized refuse

Chlorine sources and heavy metal catalysts play an important role in the formation of dioxins during the incineration of mineralized refuse in landfills. Through the use of different external chlorine sources and pretreatment methods, their effects on the formation of dioxins in flue gas from mineralized refuse incineration were studied. The effects of temperature, external chlorine sources, pretreatment methods and metal catalyst ratios on dioxin generation in the flue gas of mineralized refuse incineration were investigated with mineralized refuse. The effects of temperature, atmosphere and external chlorine source on the low-temperature re-synthesis of dioxins from mineralized refuse incineration fly ash were investigated, and the ability of re-synthesis of dioxins from mineralized refuse incineration fly ash and MSWI (Municipal Solid Waste Incineration) fly ash was compared using in situ XPS (X-ray Photoelectron Spectrometer) and heavy metal morphology analysis. The results showed that CuCl2 has the strongest catalytic effect on the formation of gaseous dioxin from mineralized refuse incineration. The components of mineralized refuse and water washing do not interfere with the mass concentration of dioxins in incinerated flue gas. The effect of temperature, atmosphere and external chlorine source on the low-temperature synthesis of dioxin from mineralized refuse incineration fly ash was similar to that of MSWI fly ash. The results of in situ XPS and speciation analysis of heavy metals show that the reducible metals in mineralized refuse fly ash was mainly composed of Fe. The stronger oxidation and chlorination of carbon and the stronger interaction between copper and iron in mineralized refuse fly ash make the dioxin synthesis capacity higher than that of MSWI fly ash. In addition, the concentration of gaseous dioxins produced by mineralized refuse incineration was directly proportional to the amount of CuCl2. However, changing the ratio of heavy metals weakened the de novo synthetic reaction to a certain extent, resulting in the change in 17 toxic dioxin isomers.