Herein, a diffusion model for the dissolution of oxide particles in multicomponent slag systems is developed. It is assumed in this model that a sharp-interface separates the solid particle from the liquid slag. Minimization of the Gibbs energy provides the conditions at the interface. The differential equations for multicomponent diffusion in the liquid slag are solved numerically via a finite-difference scheme. It is indicated via parameter studies that the diffusion controlled dissolution kinetics may result in strongly different dissolution profiles depending on the initial conditions. It is demonstrated that the rate-controlling dissipative process is the diffusion of components for cases where earlier investigations claimed that a coupled diffusion-reaction process is in charge of the dissolution kinetics. Eventually, the numerical results are compared to data obtained from high-temperature laser scanning confocal microscopy (HT-LSCM) experiments.