Froth flotation process

Claim 1

In the method for recovery of metal values by froth flotation from metallic sulfide mineral ores comprising copper and molybdenum, including the steps of: (A) forming an aqueous mineral pulp from the ore; (B) subjecting the pulp to rougher flotation to provide a scavenger feed and a rougher concentrate; (C) adding an effective amount of an alkyl mercaptan of the formula C n H 2n+1 SH in which n is at least 12 to the rougher flotation stage (B) or to the scavenger feed resulting therefrom, as a collector, and subjecting the scavenger feed to flotation to provide a scavenger tailing and a scavenger concentrate; (D) combining, regrinding, and cleaning the concentrates from the rougher and scavenger flotation states (B) and (C) to provide a copper-molybdenum cleaner concentrate; and then (E) subjecting the cleaner concentrate of step (D) to component mineral stage flotation separation; the improvement which comprises deactivating a substantial amount of the mercaptan collector on the mineral of the ore in the cleaner concentrate of step (D) prior to the component mineral stage flotation separation in step (E), said deactivating comprising adding a deactivating effective amount of activated carbon to the cleaner concentrate prior to flotation in step (E); to provide more effective mineral separation of said copper and molybdenum.