Fusion characteristics of blended ash from Changzhi coal and biomass

The blended ash fusion characteristics and its fusion mechanism of biomasses (peanut husk (PH) and rice husk (RH)) and Changzhi (CZ) coal with high melting point (MP) were investigated by ash fusion temperature (AFT) detector, X-ray fluorescence, X-ray diffraction, and FactSage software. The results show that the AFTs of CZ ash mixtures decrease with addition of biomass ash, and the fluxing effect of PH ash is better than that of RH ash, which mainly depends on their ash chemical compositions and elements existing form. The formations of low MP minerals anorthite, albite, and leucite are responsible for the decrease in AFT of PH and CZ mixtures. With RH ash addition, feldspar and eutectics are generated, resulting in a decrease in AFT of their mixtures. In the presence of Na2O, CaO, or K2O, SiO2 and Al2O3 would firstly react with them to form low MP aluminosilicate from the perspective of thermodynamic calculation, inhibiting formation of high MP mullite. The mixed ash fusion process could be divided into two major stages: fusion of K- and Ca-bearing minerals, respectively.