Abstract: A method of separating the constituent minerals of a mixture of minerals requires the introduction of fine particles of magnetic material such as finely ground particles of magnetite. The control of the zeta-potential of the minerals and particles of magnetic material provides heterocoagulation of the magnetized particles with one mineral but not the other to achieve separation. The method is ideally suitable for separating carbonates and phosphate ore and the separation process is enhanced by the addition of a surfactant such as oleate. The slurry is preferably subjected to low intensity magnetic separation to remove unattached particles of magnetic material which can be recycled to keep costs to a minimum.