Method and apparatus for separation of molybdenite from pyrite containing copper-molybdenum ores

A method and an apparatus for the separation of the mineral components of a pyrite containing copper- molybdenum ore by flotation. The method comprises grinding the ore in the presence of soda ash in an open circuit to produce an aqueous ore slurry; subjecting the slurry to a collective flash flotation step (10) in the presence of soda ash and sodium sulphide to recover a first part of metal sulphides of the ore in the form of a first concentrate (Cl); subjecting the tailings (Tl) of the collective flash flotation step (10) to a grinding step (13) and to a collective rougher flotation step (14) to recover a second part of metal sulphides of the ore in the form of a second concentrate (C3); and subjecting the concentrate (Cl) of the collective flash flotation step (10) and the concentrate (C3) of the collective rougher flotation step (14) to a selection step (12) to separate molybdenite from the other metal sulphides of the concentrate.