Slag Formation in Si and FeSi Production: Reactions Between SiO2 and Limestone or Iron Sources

• Slag formation in Si/FeSi furnaces is more substantial than traditionally assumed, with slag accumulating in inactive zones. • Slag forms from reactions between SiO2 and other oxides (e.g., CaO, Al2O3) introduced via raw materials or fluxes, with composition influenced by equilibrium or kinetics. • Trace elements like K2O significantly lower slag viscosity and liquidus temperature, promoting slag formation and affecting furnace operation. • The study provides experimental data on slag formation mechanisms, including grain boundary reactions, composition gradients, and wettability, which are critical for optimizing raw material selection and process control.