Iron chloride solutions are a waste product in steel pickling plants. A technique to recover the spent solutions is the so-called spray roasting process, where the spent solution is sprayed into a hot reaction atmosphere and solid iron oxide particles are formed. The particle formation in spray roasting reactors has important influence on the efficiency of the recovery process and on the quality of the desired by-product Fe2O3. A laboratory reactor was designed to investigate the particle formation. Experiments were carried out covering the predominant conditions in spray roasting reactors. The results offer valuable insight into the particle formation process, providing data on the surface structure of the Fe2O3 particles formed and on the progress of chemical conversion. Based on these results, a simplified model applicable to CFD-modelling of spray roasting reactors has been developed. Simulations of particle trajectories in the laboratory reactor are presented to show the capabilities of the model. (C) 2012 Elsevier B.V. All rights reserved.