Study On The Haracteristics And Chemical Stabilization Municipal Olid Waste Incineration Fly Ash

Having the advantages of remarkable volume-reduction, small floor area and Energy-recovery, disposing of Municipal Solid Waste(MSW) by incineration which meets the situation of our country have been widely used by in most large and medium-sized cities.Incineration fly ash contains many heavy metals and dioxins, so it is regarded as hazardous waste and need be stabilized before disposal.In the mainstream treatment of incineration fly ash, solidification and stabilization have been widely used by domestic and overseas.This paper firstly analyses the basic characteristics,contents and distribution of heavy metals of fly ash, and it is treated by a compound stabilization using cement-phosphoric acid or cement- chelating agent. Getting the following main conclusions.1. Incineration fly ash of the experiment with small particle sizes and substantially under the 38μm; The scanning electron photomicrograph of the fly ash shows that the volume of ash is small, the roughness of the surface; it has loose,porous structure and large specific surface area. In incineration fly ash the principal elements are Ca、Cl、K、S、Si、Fe, the mainly crystal structure are KCl, NaCl, CaClOH,CaSO4, CaCO3, Ca(OH)2, the crystal structure of heavy metals have close correlation with sampling in different seasons or conditions of incineration.2. Heavy metal content of fly ashes in different seasons has a similar distribution, and the sequence contents is Zn>Pb>Cu>Cd>Cr>Hg>Ni;Concentrations of Cd、Pb、Zn and Cu,decreased with the decrease of particle sizes, but the variation law of other heavy metals are not. According to analysis of heavy metals distribution,Ni mainly takes up as residue and Cd, Cu, Pb mainly takes up as reducible; In various size faction of fly ashes,Cd,Pb is basically and takes up as reducible, and enriched in the larger size.3. The cement-phosphoric acid stabilization, has obvious treatment of Cd, Zn,Pb when the phosphoric acid was 1.5%, and the effect for Pb was clearest, and Cu、Pbhave transformed to steady states.4. The cement- chelating agent stabilization has obvious treatment of Cu, Cd,Zn, Pb, Ni, each heavy metals have transformed to steady states, and the effect for Cu,Cd, Pb was clearest.