5. Mineralurgy

In most cases, rhenium recovery involves concentrating molybdenite from copper-molybdenum porphyries (figure 1 ).

• The first stage of the recovery process consists of global flotation of copper (chalcopyrite) and molybdenum sulfides to give a mixed concentrate, using collectors (xanthates or dithiophosphates), a basic pH regulator (lime) and a foaming agent (methyl isobutyl carbinol, MIBC).

• The concentrate is then treated by decomposing the adsorbed xanthates by roasting at around 400 ˚C (Utah process) or by steam heating, or by depressing the chalcopyrite with ferrocyanide,...