Magnetic separators have unrestricted industrial application and are widely used in mineral beneficiation, food, textiles, plastic and ceramic processing industry. Separation efficiency of magnetic separator depends on material characteristics and the design features of equipment along with the optimization of process variables. This study is based on a novel application of image processing technique to capture the particle trajectory on induced roll in an electromagnetic separator while treating magnetic particles. Three different minerals of different magnetic susceptibility were selected to investigate this approach. Trajectories of 3 mm diameter balls of mineral fines were captured using an image analyzer at different operating conditions. The particle trajectory captured was compared with the trajectory predicted by Cakir mathematical model. The separation angle between roll and particles was considered as a separation performance measure. It was found that Cakir mathematical model produce reliable result and a new model was proposed to increase the reliability of separation angle prediction by including the particle shape factor. The proposed model can be utilized to optimize the magnetic separation process while treating paramagnetic minerals. (C) 2013 Elsevier B.V. All rights reserved.