Motion and capture simulations of magnetic particles in centrifugal DMS process

Centrifugal dry magnetic separation (cDMS) is an effective technology for processing fine dry ore powders, as it significantly reduces the lower particle size limit from -150 μm in the conventional DMS separators to -37 μm, at a much higher separation accuracy. The motion trajectories and capture behaviors of magnetic particles in the cDMS process were systematically investigated, to elucidate the underlying cDMS mechanisms using an established simulation model; and, the interactions between magnetic and non-magnetic particles during separation were revealed. Simulation results indicate that magnetic particles move in spiral trajectories and form a helical ”magnetic chain” on the separation cone surface, under the action of magnetic force and tangential friction resulted from the rotation of cone, which significantly extends the separation path of magnetic particles and thus improves its separation selectivity. Furthermore, the volume susceptibility, shape, and density of magnetic particles have significant impacts on their motion trajectories and capture behaviors. It was found that magnetic particles would entrain non-magnetic ones in the cDMS process, significantly prolonging the motion trajectories of non-magnetic particles and causing the inclusion of non-magnetic particles into magnetic product. This investigation clarified the motion and capture behaviors of magnetic particles in the cDMS process, providing an important theoretical foundation for the development of cDMS technology.