Abstract: Aiming at the predicament of the sulfur-cobalt mixed concentrate (with a cobalt grade of 0. 33% and a sulfur
grade of 31. 92%) obtained by flotation in a titanium concentrator in Southwest China,such as the cobalt content failing to
meet the pricing standard and the value not being fully realized,this study starts with process mineralogy. It is clarified that cobalt
is mainly hosted in cobalt-nickel-bearing pyrrhotite and hengleinite,with a monomer dissociation degree of over 87%. On
this basis,the traditional pretreatment framework of regrinding and reagent removal is broken through,and a new process of direct
flotation separation of raw slurry using high-efficiency selective reagents is proposed. A combined reagent system of "composite
calcium activator + EMZ5# depressant" is developed. The closed-circuit test of raw pulp flotation separation with the
process of "one roughing - one scavenging - three cleanings" (without reagent removal and regrinding) yields a value cobalt
concentrate with a Co grade of 2. 25% and a Ni grade of 4. 84%,with the recovery rates of both around 80%. For the sulfur
concentrate,the S grade reaches 31. 82%,with its Co and Ni contents reduced to 0. 07% and 0. 18% respectively,achieving efficient
separation and enrichment of cobalt-nickel minerals. The research shows that the raw pulp flotation separation process
has significant advantages in simplifying the process,reducing energy consumption and costs,and provides a new technical direction
for the efficient utilization of low-grade cobalt-sulfur resources.