Thermal Synergistic Treatment of Municipal Solid Waste Incineration (Mswi) Fly Ash and Fluxing Agent in Specific Situation: Melting Characteristics, Leaching Characteristics of Heavy Metals

Abstract

The melting-solidification on the horizontal cyclone furnace plays an irreplaceable role in realizing the utilization of ash. The purpose of this research is to simulate and obtain the fly ash molten glass at the local location of the horizontal cyclone furnace utilizing a small high-temperature test bench in the laboratory. The influence of the fluxing agent (CaO, SiO2, Al2O3, and coal ash) was explored on the melting of MSWI-fly ash in the complex atmosphere from the combustion of CH4 with SEM-EDS, XRD, ICP-AES analysis methods. The results show that in order to obtained low melting-point minerals (anorthite, pearl mica, etc.), it requires SiO2=30 wt.%~37 wt.%, CaO=28 wt.%~34 wt.%, Al2O3=17 wt.%~28 wt.%, and alkalinity(B)=0.5~0.7. CaO, SiO2, and Al2O3 have significant effects on the deformation temperature, flow temperature, and melting temperature difference, respectively. In order to obtain [SiO4] and [AlO4] tetrahedrons encapsulating heavy metals and make the glass phase concentration more than 85%, it requires CaO≤30 wt.%, and concentration ratio of SiO2 and Al2O3 should be controlled within 1~1.5. The significance of this research is to standardize the operation of the horizontal cyclone furnace and obtain a molten glass that meets the national standard.

Keywords: MSWI-fly ash, Complex atmosphere, Fluxing agent, Heavy metals, Melting characteristics