Slag corrosion of MgO–C refractories during secondary steel refining

Studies of the reactions between the MgO–C refractory and a CaO–Al₂O₃–SiO₂–MgO slag system have been carried out through thermodynamic simulations, laboratory experiments and microscopy studies of the microstructure of the refractory samples after the experimental procedures. Corrosion experiments were conducted using the rotating immersion method of the MgO–C refractory rods in a liquid slag: in the temperature range of 1773–1923 K, revolution speed of 200 rev min⁻¹, with varying slag compositions and times (2700–8100 s). Laboratory experiments have shown that the time during which the ladle lining is exposed to a liquid slag with high stirring and slag composition are two important parameters which have large effect on the kinetics of the refractory wear. The rate constants calculated in the present work are in the range of 4×10⁻⁷ to 1×10⁻⁶ m s⁻¹. The estimated activation energy from the experimental results is 26 kJ mol⁻¹.