The kinetics of the dissolution of oxide particles in metallurgical slags is simulated by means of a sharp-interface finite difference model where multi-component diffusion is considered. The effect of convective fluxes on the dissolution kinetics is being considered by a constrained boundary layer thickness. The thickness of this boundary layer can be estimated from theory and is used together with the interdiffusivity matrix to predict the dissolution kinetics of spherical alumina particles in various CaO–SiO 2–Al 2O 3 slags. The numerical results are compared to experimental observations using High-Temperature Confocal Scanning Laser Microscopy (HT-CSLM).