Thermodynamic Properties, Viscosity, and Structure of CaO–SiO2–MgO–Al2O3–TiO2–Based Slag

Abstract

The effect of TiO₂ and the MgO/Al₂O₃ ratio on the viscosity, heat capacity, and enthalpy change of CaO-SiO₂-Al₂O₃-MgO-TiO₂ slag at constant heat input was studied. The variation of slag structure was analyzed by the calculation of activation energy and FTIR spectrum measurements. The results showed that the heat capacity and enthalpy change of the slag decreased with the increase of TiO₂ content. Under constant heat supply, the fluctuations in slag temperature were relatively apparent, and the temperature of slag increased as the TiO₂ content increased. The viscosity of slag decreased due to the increase in slag temperature. Increasing the MgO/Al₂O₃ ratio could decrease the temperature and viscosity of slag. The effect of increasing the MgO/Al₂O₃ ratio on the viscosity was more pronounced than the decreasing temperature caused by increasing the MgO/Al₂O₃ ratio. The apparent activation energy decreased with increasing TiO₂ content and MgO/Al₂O₃ ratio. The Ti-O bonds formed with TiO₂ addition, and the Ti-O bonds were weaker than Si-O bonds, which resulted in the decrease in heat capacity and viscosity of slag.