This paper reports the study of a High-Gradient Magnetic Separation (HGMS) process for the treatment of industrial wastewaters that considers an assisted chemical-physical pre-treatment for the removal of heavy metals through the bound by adsorption with added iron-oxide particulate matter (hematite). The considered filter, constituted by ferromagnetic stainless steel wool and permanent magnets, is studied with a new approach based on a statistical analysis that requires the study of the trajectories of the particles. Experimental activity on a laboratory device has been carried out in order to test the model. (C) 2010 Elsevier B.V. All rights reserved.