Experimental Study On The Melting Of Municipal Solid Waste Incineration Fly Ash

Having the advantages of remarkable volume-reduction, weight-reduction and energy-recovery, disposing of Municipal Solid Waste (MSW) by incinerations have been widely used abroad during the past twenty years. Nowadays this technology is being popularized gradually in our country. Yet the release of toxic substances such as heavy metals and dioxins bring environmental problems. In the fields of treatment of hazardous MSWI fly ash, the thermal melting process becomes one of most significant research community.The physical-chemical properties of the ash samples, such as major compositions, trace elements of hazards (dioxins and heavy-metals), porosity and morphology were successively analyzed by Electron Spectroscopy, Atom Absorbing Spectrum, GC-MS and Poremeter, respectively.The experiments were developed depend on the physical-chemical properties of the molten slag of the MSW, firstly, the component of the fly ash were analyzed, the experiments were conducted in a self-developed batch system and the molten slag were analyzed; reduction characteristic is one important advantage of melting treatment method, the influences of operational condition on reduction characteristics were investigated, while the considerable variables include process temperature, atmosphere and additional reagent. The thermal analysis were performed to study the thermal characteristics of the molten slag, also the XRD analysis were performed to study the non-crystal characteristic of it.The thermodynamics and kinetics of melting process of MSWI fly ashes were characterized on basis of experimental evidence. Experiments were conducted in a micro-scale high temperature DSC-DTA system. The heat of melting transition as well as the sensible heat during the process was measured.The partition of heavy metals during melting process was also studied. Influences of temperature, atmosphere, time, and additional reagent on the solidification of heavy metals were considered. It is concluded that the partition characteristics of during ash melting greatly differs for each kind of heavy metals. The control of secondary pollutants of melting process was considered. The degradation of dioxin during melting process was studied in lab-scale batch system. Experimental results indicate that the great part of dioxins with MSWI fly ash degrades.