Effect of changing slag composition on spinel inclusion dissolution

The rate of MgAl2O4 spinel inclusion dissolution in CaO–SiO2–Al2O3 slags at 1504°C has been measured using a laser scanning confocal microscope. It was found that the mechanism of spinel inclusion dissolution was at least in part controlled by mass transfer in the slag phase for the slag compositions used. Evidence in support of this finding was that the calculated diffusion coefficient was inversely proportional to the slag viscosity and that the diffusion coefficients were in reasonable agreement with those obtained in a separate study on alumina dissolution. The diffusion coefficients obtained were in the range of 0·76–2·2 × 10−10 m2 s−1.