Distribution of Cobalt in Mineral Constituents of the Merensky Reef and UG-2 Chromitite Layer of the Bushveld Complex

摘要

Trace amounts of cobalt are incorporated in almost all the constituents of the Merensky Reef and the UG-2 Chromitite Layer of the Rustenburg Layered Suite in the Bushveld Complex. Although the cobalt concentration in silicates and chromites is low, ranging up to 800 and 700 p.p.m. respectively, the proportion hosted by these minerals is large because they are the predominant constituents of the rock. In the Merensky Reef, the silicates are major constituents, so the bulk of the cobalt is present in them; in the chromite-rich UG-2 layer, the major proportion is present in chromite. Only the cobalt that is locked up in sulfides can be extracted during beneficiation of the platinum-group minerals and, because the sulfide content of the reefs is very low, the total amount of cobalt that can be recovered is also low.