Abstract
South Africa host massive deposits of Platinum Group Metals (PGMs) in the Igneous
Bushveld Complex. These deposits have been mined for a long time and in the process
Mine sludge has been produced. It has been piled up and there is need to recover PGMs
locked in it. The conventional way of processing PGMs has proved to be very difficult
due to ultra-fines in the sludge that causes major loses during flotation. An alternative
hydrometallurgical process for recovery of PGMs from a mine sludge by leaching using
a mixture of hydrochloric acid and different oxidizing agents was investigated. It was
found that the mine sludge contained 8.93 g/t Pt, 6.99 g/t Pd, 2.79 g/t Ru and minor
percentages of Rh, Ir, and Au. It had a particle size distribution (PSD) of 84.64%
passing 38 microns. Major mineral phases present are sphalerite, chalcopyrite,
pentlandite, covellite, bornite, chromite, and silica as the main gangue. HCL + H2O2
(1:1) combination managed to leach all the PGMs and gold. HCL + Ferric Chloride
(1:1) combination managed to leach Pt, Rh and Ru very well but it could not leach Pd.
Further investigation on the optimization of the leaching conditions is being done.