Effect of Stone Coal Chemical Composition on Sintering Behavior during Roasting

During the roasting of stone coal, a sintering phenomenon usually occurs, which is related to the chemical composition of the stone coal. In this study, the sintering beginning temperature (SBT) and ash fusion temperatures (AFTs) of stone coal with different CaO, Fe2O3, SiO2 and Al2O3 content were investigated. FactSage has been used to calculate the phase distribution of roasted stone coal, to analyze how these components influence the sintering behavior during roasting. For stone coal with low CaO content, CaO reacted with albite, leucite, and quartz to generate an amorphous phase, which would easily cause sintering, while for stone coal with high CaO content, CaO took part in the formation of andradite and Na2Ca3Si6O16. Most Fe2O3 in roasted stone coal stably existed as hematite in the system and did not react with others, which had almost no effect on sintering. SiO2 and Al2O3 in the stone coal contributed to hinder the formation of amorphous phases, especially for high Al2O3 stone coal, in which mullite was generated.