Applying an equivalent free settling ratio to enhance ferro-magnetic and para-magnetic particles’ separation efficiency using the influence of a magnetic field aligned with gravity

ABSTRACT Settling behaviour of particles in aqueous mediums depends on the resultant force acting on them. This force normally is the resultant of gravity, buoyancy and drag forces. Therefore, the settling velocity of coarse and light particles is very close to that of fine but dense particles. This fact is the major cause of poor beneficiation of fine valuable minerals in gravitational separation devices like spirals. So, implementing of an external force such as magnetic force may well improve the beneficiation of such particles. Theoretical analysis of terminal settling velocity (TSV) of particles shows that a magnetic field aligned with gravity can increase TSV of minerals with magnetic properties which in turn results in higher free settling ratios between magnetic and non-magnetic particles. In this regard, an innovative laboratory device was designed, fabricated and used to better understand the simultaneous effects of gravity and a magnetic force aligned with it.