The influence of the reagent suite on the flotation of ores from the Merensky reef

A number of operations recover platinum group elements (PGE) from the Merensky reef in the Bushveld Complex, South Africa. The Merensky reef contains approximately 1% sulphides in the form of chalcopyrite, pentlandite and pyrrhotite, and the PGE’s are strongly associated with these sulphides. Different operations use different reagent suites (collectors, depressants, activators and frothers) in the flotation process to extract the valuable minerals from their section of the reef. Batch flotation tests were done on two ores from different parts of the reef using three different reagent suites based on the typical suites presently in use, and the recovery of the sulphide and gangue minerals compared. The two ores responded in a similar manner to the three reagent suites although there were differences observed in the behaviour of the individual minerals. These differences and the reasons for these differences are discussed.