Experimental study and industrial practice on flotation recovery of a primary copper-sulfur-cobalt ore from DR Congo

This paper focuses on a copper-sulfur-cobalt ore from a deep deposit in the Democratic Republic of Congo, where the metallic minerals are predominantly chalcopyrite, carrollite, and pyrite, with minor amounts of copper-bearing minerals including chalcocite, digenite, bornite, and covellite, while the gangue minerals mainly consist of quartz and dolomite. Chemical phase analysis shows copper primarily exists as primary copper sulfide, followed by secondary copper sulfide with minor combined and free copper oxides, and cobalt mainly occurs as sulfide along with combined and trace oxidized cobalt. Through systematic beneficiation tests conduct in accordance with the ore characteristics and operational parameters specific to the Democratic Republic of Congo（DRC）, which ultimately established a bulk flotation process for copper-sulfur separation under low-alkalinity conditions（pH≤8）. The process configuration incorporates lime as a copper regulator, butyl xanthate as the primary collector, and No.2 oil as the frothing agent. Under the condition that the primary grinding fineness of the raw ore reaches 76% passing 0.074 mm, and for raw ore with copper, cobalt, sulfur, and iron grades of 2.46%, 0.098%, 2.69%, and 2.64% respectively, the closed-circuit test produce a copper-cobalt sulfide concentrate with a yield of 9.56%. The concentrate assay 24.56% Cu, 0.86% Co, 26.77% S, and 22.55% Fe, with corresponding recovery rates of 95.07%, 84.25%, 95.20%, and 81.75%, respectively, demonstrating effective comprehensive recovery of valuable minerals from the ore. The results of this paper can provide a technical reference for the smelting treatment of the same type of ore.