Spray roasting of metal chloride solutions is frequently used in steel industries to recover pickling liquids. As spray roasting reactors are difficult to characterize experimentally, computational fluid dynamics simu- lations have been used to investigate reactor performance. These simulations require a particle formation model, which describes the particles size history including the characteristic effect of particle swelling. Based on available literature, different swelling models are compared by simulations of an industrial scale reactor. The influence of particle swelling is discussed. The results clearly indicate the necessity to investi- gate particle swelling, potential collision effects and fragmentation for sound simulation of spray roasting reactors.@en