Quantification and analysis of slag carryover during liquid steel tapping from BOF vessel

Abstract

The amount of slag carryover (SCO) during the liquid steel tapping from the basic oxygen furnace (BOF) vessel has been estimated using a thermodynamic model that ensures the matching the predicted bath silicon with that of experimentally measured silicon in ladle furnace. FactSage 6.4 has been used for thermodynamic analysis. A simple correlation has also been established to estimate SCO immediately after the tapping process using the readily available plant data. Viscosity, interfacial tension of the slag, impurities in the liquid steel, and the tapping temperature has been found to have a profound effect on the amount of SCO. The advantage of the present method of SCO estimation compared to the other methods and the industrially viable control measures for minimising SCO is discussed in light of clean steel practices. Further, industry trials have been conducted to validate the control of SCO by tuning the BOF slag properties.