The Recovery Of Pgms From The UG2 Silicate Stream By Fine Grinding And Froth Flotation

Abstract

– The Bushveld Igneous Complex (BIC) hosts the largest reserves of Platinum Group Metals (PGMs) in the world with most of the Platinum Group Element (PGE) mineralization occurring within the Merensky Reef, UG2, Platreef and Middle Group Chromitites reef. This research sought to investigate the PGMs locked in the silicates of the UG2 ore from the Eastern Limb. As most of the PGMs are locked in the silicate stream, these are disposed in the tailing dams. The silicate stream was characterized using the XRF, XRD, SEM and fire assaying through nickel sulphide collection. 1kg of the sample was milled in the rod mill to 80% passing 53 µm and floated in a D12 Denver flotation cell to recover the PGMs from the silicate stream based on Response Surface Methodology. It was found that the major mineral phases in the silicate stream were quartz, sphalerite, pyrrhotite, chalcopyrite and chromites. The size of the sulphide mineral that hosted the PGMs in the silicate was 20 µm. The highest concentrate grade obtained after flotation was 19.19 g/t of Pt. The as-received sample also had 0.95 g/t of Au which was recovered.