Analysis of the Influence of Additions of Flux, SiO2, and Al2O3, on the Desulfurization Efficiency of Hot Metal Using Global Desulfurization Factor

The formation of the solid phases CaS, 3CaO.SiO₂ and CaO.Al₂O₃ around the lime particle decreases the efficiency of desulfurization by the kanbara reactor (KR) process. The addition of fluxes reduces the formation of these phases. The addition of Al and Si can also have this effect, depending on the added levels. In this study, different mixtures based on CaO with different levels of fluorspar, sodalite (Nepheline Syenite), and SiO₂ and Al₂O₃ content were studied and used in the desulfurization process of hot metal. These mixtures were added to a bath of liquid hot metal at 1400 °C. All experiments were performed with mechanical agitation. Samples were taken at times of 5, 10, 15, and 20 min, and analyses were performed to evaluate the variation of sulfur over time. The Thermo-Calc software was used to determine the formed phases, solid fraction, and liquid fraction of the different mixtures. With this data, different values of the Global Desulfurization Factor (FG_DeS) were calculated, which was developed to evaluate and predict the efficiency of hot metal desulfurizing mixtures by the KR process. The results of showed that fluorspar was more efficient than sodalite. The FG_DeS had a correlation factor (R²) above 0.9 with the desulfurization efficiency.