Differential classification of dense material in a three-product cyclone

A hydrocyclone with two concentric vortex finders, named the three-product cyclone, has been successfully tested in the Platinum industry for classifying UG2 ore which contains a high density chromite and a low density PGM carrying silica component. The low density silica reports to the overflow even when not sufficiently fine enough for flotation, which results in loss of recovery through over-size silica component material in the float feed. s from industrial plant trials conducted using a 600 mm diameter three-product cyclone are presented. The three-product cyclone produced a middlings product containing the majority of the oversize silica that would normally report to the overflow. The middlings from the three-product cyclone represents a small percentage of the total cyclone feed and can be treated separately by fine screening to return the coarse silica to the mill for further grinding.