Increased selectivity in continuous axial HGMS separators

High selectivity in the separation of multicomponent particle systems has been achieved using high-gradient magnetic separation (HGMS) in the axial configuration, especially in the repulsive mode. Increasing the length of the separator can provide higher material throughput as well as increased selectivity. The higher superficial velocity reduces retention of material, a crucial requirement for higher selectivity. A single-stage separator works in the repulsive mode for only one of the particle components if the carrier fluid has magnetic susceptibility in between those of the particulates. The authors have achieved high selectivities for both components of a two-component slurry (CuO and Al in MnCl₂) by using a two-stage separator with the second stage operated orthogonally (with respect to field direction) to the first. An axial separator has been applied to coal-pyrite separation