Effect of slag composition on desulfurization and inclusion modification during ladle furnace refining

Abstract

The influence of LF refining slag composition on desulfurization and inclusion modification was investigated through industrial experiments and thermodynamic analysis. The results show that the sulfide capacity decreases with the decrease in (%CaO)/(%SiO2) and (%CaO)/(%Al2O3) of the slag. The theoretical sulfur distributions agree well with the analysis results when the sulfide capacity is calculated by Zhang's model, but the theoret- ical sulfur distributions are higher than the analysis results when the sulfide capacity is calculated by the KTH model. During the LF refining process, inclusions are transformed from Al2O3 inclusions into CaO-MgO-Al2O3 system inclusions. Higher slag basicity results in higher CaO and MgO and lower Al2O3 content inclusions in molten steel at the end of the LF process.