Simulation of magnetic particle suspensions using the Stokesian dynamics technique

The dynamic behaviour of ferromagnetic particle suspensions is of interest in various technical applications, including separation processes in the mining industry. In this work, an implementation of magnetic particle interactions within a Stokesian dynamics simulation framework is presented.Stokesian dynamics is a particle-based, mesh-free method developed for nm to mm size particles in static or flowing liquid suspensions. Particle-fluid and pairwise hydrodynamic interactions are included in the technique, and additional external or interparticle forces can be included depending on the size of particles and the properties of the system under consideration. In this work, we include models to allow for 3D simulation of magnetic particles in the presence of an external magnetic field. A single magnetic point source can be arbitrarily assigned within the simulation domain. The magnetic interaction model includes macroscopic particle-field interactions as well as pairwise interactions between nearby particles, resulting from field-induced particle magnetization.Results are compared with laboratory tests using a bench-scale flow cell. It is demonstrated that Stokesian dynamics is a feasible technique for numerically studying the behaviour of ferromagnetic systems. The applicability of the method for understanding and predicting particle level mechanisms of relevance for the efficiency and selectivity of mineral separation processes such as wet low-intensity magnetic separation (LIMS) is discussed.