Corrosion mechanism and kinetic behaviour of MgO–C refractory material in contact with CaO–Al 2 O 3 –SiO 2 –MgO slag

The rate of dissolution of solid MgO–C into liquid CaO–Al 2 O 3 –SiO 2 –MgO slag at different temperatures was studied under conditions of forced convection by rotating cylindrical refractory specimens in a stationary crucible containing molten slag. The corrosion rate was calculated from the change in diameter of the cylindrical refractory specimens. The specimens were rotated for 15–120 min at a speed of 100–400 rpm in the molten slag. The rate of corrosion was found to increase with an increase in temperature and rod rotation speed, and to decrease when the slag was nearly saturated with MgO. The experimental results support the assumption that the diffusion of magnesium oxide through the slag‐phase boundary layer controls the corrosion process. The corrosion mechanism seems to be the dissolution of refractory material into the slag followed by penetration of pores and grain boundaries and dispersion of the grains into the slag.