[Fundamental properties of fly ash from municipal solid waste incineration]

Fundamental properties and the factors that influence the distribution of heavy metals of several fly ashes are analyzed. Experiments indicate that the structures are complex and the properties are changeable. The study results show that the chemical composition is Cl, Ca, K, Na, Si, Al, O, etc, and heavy metals are Zn, Pb, Cr, Cu etc. The main structures of fly ash are irregularly amorphous forms and polycrystalline aggregates. Generally, the ieaching toxicity exceeds the identification standard for hazardous wastes. Heavy metals are chiefly in the forms of tiny aerosol particles and aggregates on the surface of fly ash. The properties of fly ash are greatly influenced by the change of incinerators or the variation of incinerating time. The content of Cl ranges from 6.93% to 29.18%, while that of SiO2 does from 4.48% to 24.84%. The leaching toxicity varies between 0 and 163.10 mg x L(-1) (Pb) and between 0.049 and 164.90 mg x L(-1) (Zn).