In situ observation of the dissolution phenomena of SiC particle in CaO–SiO2–MnO slag

The dissolution of SiC particle at 1600 °C in the CaO–SiO2–MnO slag was observed in situ by means of confocal scanning laser microscopy in order to make the determination of dissolution mechanism. The SiC particle is initially wetted by molten slag from the outer surface and the wetting between SiC and slag phase is more dominant in the composition of higher CaO/SiO2 ratio. When the SiC particle is wetted by molten slag, the gas bubbles that are mainly CO gas is generated by the reaction between SiC and MnO in slag phase and are continuously evolved at the wetted area, which is pronounced as the CaO/SiO2 ratio increases. The dissolution of SiC particle in the slag through the reaction with MnO is enhanced in the composition of higher CaO/SiO2 ratio not only due to greater thermodynamic driving force but also due to accelerated mass transport kinetics.