The viscosities of the industrial basic oxygen furnace (BOF) slag with varying compositions of MgO, Al₂O₃, TiO₂, and MnO were continuously measured at a temperature range between 1400 and 1700 °C using the rotating bob method. Three characteristic temperatures for the melting behavior of the BOF slag were investigated using a high-temperature microscope. The solid fraction of the slag was calculated by FactSage 7.2 using the FTOxid database. General observations from the experimental data show that the increase in MgO tends to increase viscosity. However, Al₂O₃, TiO₂, and MnO decrease viscosity up to a certain level, and beyond that, they also increase the viscosity. The measured values of the viscosity of BOF slags were compared and discussed with known data from the literature. Finally, the activation energy of BOF slags with different compositions of MgO, Al₂O₃, TiO₂, and MnO was calculated in the temperature range of industrial operations.

In the present work, the calculations of the modified operating line for the COREX process, based on the Rist diagram approach, have been performed. The operating line developed by Rist in 1960's has been modified by various researchers for improvements in the blast furnace. The idea proposed by Rist was further utilized to perform the heat balance along with the net oxygen balance for the other iron making processes. The operating line has been modified thus accounting the generated H2O and CO2 with respect to Fe, in the process of smelting reduction of ore by coal containing volatile and moisture.