The influence of the high potassium biomass on the ash fusion characteristics of coal

Abstract The influence of high potassium biomass (corn straw (CS)) on ash fusion temperature (AFTs) of Jincheng coal (JC) was explored by X-ray fluorescence (XRF), intelligent ash fusion point tester, X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS). The results show that the method of adding CS can effectively reduce the AFTs of JC. The main mineral composition of JC ash at high temperatures is refractory Al6Si2O13, which is why JC has a higher AFTs; the main mineral composition of CS ash at high temperatures is its ash with a large amount of Ca/Mg-containing aluminosilicates and glassy substance containing metal potassium (K), which is why CS has a lower AFTs. With the increasing of the proportion of CS added, Al6Si2O13 as the main mineral component in JC ash gradually converts into a series of new Ca/K-containing aluminosilicates (such as, diopside (CaMgSi2O6), leucite (KAlSi2O6), etc.), which results in the reduction of the AFTs of JC. Meanwhile, the Ca/K-containing aluminosilicates has a low-temperature co-fusion effect. In addition, SiO2 and Al2O3 together in coal ash have excellent K-fixing efficiency confirmed by the formation of stable K-containing aluminosilicates.