The present study concerns the optimization of a process where solid particles are coated through the interaction of a particulate flow coming out of a cyclone with a spray issuing from a pressure atomizer. Since the industrial process could not be studied in detail experimentally, numerical calculations of the multiphase flow process using the Euler/Lagrange approach were used to optimize the coating efficiency. The gas flow was calculated by solving the Reynolds-averaged Navier-Stokes equations in connection with the k-ε turbulence model and appropriate source terms for the dispersed phase. The particle and droplet phase was simulated with the Lagrangian approach where a large number of computational particles are tracked through the flow field. The calculations take into account the particle and droplet size spectrum. The latter was obtained from measurements by Phase-Doppler anemometry. Turbulence effects on droplet and particle motion are considered by using a Langevin-equation model. For allowing the calculation of the coating efficiency a stochastic approach is used to model collisions between droplets and particles. In order to determine the mass of liquid deposited on the particle during impact correlations from detailed micro-physical experiments are used and implemented in the stochastic collision model. Based on the calculations an optimized configuration of the spraying chamber could be suggested.