Sequential flotation of sulfide ores

In a sequential flotation process for the separation of components of a mineral mixture of the type wherein a primary grind ore pulp is routed sequentially through a series of flotation circuits having successive separation and concentration stages for separating and concentrating one of the mineral components, the improvement comprising:

• grinding a sulfide ore comprising a mixture of copper, lead and cobalt-nickel sulfide minerals in a carbonate matrix to provide a primary grind flotation pulp;
• conditioning the pulp with SO.sub.2 under intense aeration to depress lead and cobalt-nickel and promote copper;
• routing the conditioned pulp to a copper flotation circuit having a roughing stage and at least one cleaning stage;
• effecting flotation of the copper and separating a copper rougher concentrate from a copper rougher tailing product;
• regrinding the copper rougher concentrate to liberate lead and cobalt-nickel minerals and conditioning the reground concentrate with SO.sub.2 ;
• cleaning the reground conditioned rougher concentrate and separating a first copper cleaner concentrate from a first copper cleaner tailing product;
• routing at least the copper rougher tailing product directly to the lead flotation circuit wherein a lead concentrate is separated from a lead tailing product;
• routing the lead tailing product from the lead flotation circuit to a cobalt-nickel flotation circuit wherein a cobalt-nickel concentrate is separated from a cobalt-nickel tailing product;
• and
• recovering the copper, lead and cobalt-nickel concentrates from their respective flotation circuits.