Influence of CaF2 in calcium aluminate-based slag on the degradation of magnesia refractory

High temperature experiments were carried out using an induction furnace to simulate the refractory-slag-metal reactions in conjunction with thermodynamic computations using FactSage7.0 software. The Al-killed steel and the CaO-Al2O3-8SiO(2)-5MgO-xCaF(2) (CaO/Al2O3 = 1.9, x = 0-15 wt%) slag were brought to equilibrium in a magnesia refractory at 1823 K. Moreover, the solubility of MgO in the slag was quantitatively measured using a resistance furnace as a function of CaF2 content and temperature to confirm the thermodynamic driving force of the dissolution of MgO. The penetration depth of a slag into the magnesia refractory increased with increasing CaF2 content, which originated from a decrease in slag viscosity. Also, it was confirmed that MgO grains were dynamically detached from the slag/refractory interface by increasing the content of CaF2.