Agglomeration-flotation of finely ground chalcopyrite using surfactant-stabilized oil emulsions: Effects of co-existing minerals and ions

As high-grade and easily exploitable copper ores have been getting depleted, the development of flotation techniques for copper ores with low-grade and small grain size is becoming an important issue. To process these kinds of ores, fine grinding is essential to achieve sufficient liberation; however, flotation rate of finely ground minerals ( 5 mu m) is substantially low due to the low collision probability between air bubbles and mineral particles. Agglomeration-flotation using surfactant-stabilized oil emulsions was effective to improve the recovery of finely ground chalcopyrite. In this study, the effects of emulsifiers in the presence of co-existing minerals and ions on agglomeration-flotation of finely ground chalcopyrite were investigated. The addition of anionic emulsifiers (SDS, KAX) could stabilize the oil-water emulsion and produce smaller oil droplets, which improve Cu recovery in the agglomeration-flotation of chalcopyrite and quartz from -68% (without emulsifier) to 97% (with emulsifier). When Ca2+ and quartz co-existed, the amounts of SDS used as emulsifier were reduced due to its adsorption onto the surface of Ca2+ activated quartz, which caused the coalescence of oil droplets resulting in low Cu recovery (i.e., 81% with quartz only; 44% with quartz and Ca2+). Meanwhile, emulsified oil stabilized by KAX was not affected by the presence of Ca2+ and quartz, and high Cu recovery (-83%) could be obtained.