[Characteristics of melting and solidification process of fly ash from refuse incinerator].

This study was conducted to investigate the migration patterns of main compositions of the fly ash from refuse incinerator during melting and solidification process. The experiment was performed in a high temperature melting furnace with temperature controlled. X-ray fluorescence spectroscopy (XRF) and X-ray diffractometer (XRD) were used to analyzed the fly ash treated. The parameters investigated included main compositional contents, phase constituents, alkalinity, vaporation rate, volume reduction rate. The results show: (1) During the melting and solidification process, the contents of CaO, Al2O3, and SiO2 in fly ash increased as the temperature went up, but element Cl and S decreased from initial 20.59%, 10.74% to final 0.15%, 0.22%, respectively. This suggests that higher amount of Cl and S in original fly ash could lead to more vaporation in the form of chloride and calcium salfate in the process, which was further verified by XRD analyzing result. (2) The alkalinity decreased as melting temperature increased, but tended to be stable and maintained around 0.95 after temperature reached flowing temperature. (3) The decomposition and vaporation of the salts in the fly ash mainly occurred in the temperatures between 1150 degrees C and 1260 degrees C, which was approximately 100 degrees C lower than melting temperature.