Study on flotation and magnetic separation metallurgical experimental of low grade high oxidation copper-cobalt ore in SCM Mine Area, DRC

In a low grade copper-cobalt ore in SCM Mine Area, DRC, the copper mainly exists in the form of free copper oxide and combined copper oxide, along with a small amount of secondary copper sulfide and little primary copper sulfide; the cobalt is mainly in the form of cobalt oxide such as heterogenite, spherocobaltite, cobalt dolomite, etc. The copper and cobalt ores are in a complex state and difficult to recover. According to the nature of the ore and actual production requirements, the process featured by “pre-flotation of sulfide ore-sulphidizing flotation of oxide ore-magnetic separation-leaching” is adopted to investigate the influence of the type of sulfurizing agent, the chemical system and magnetic field strength of flotation on the separation index of copper and cobalt, as well as the leaching effect of copper and cobalt under the conventional leaching conditions. The results show the selective separation of copper-cobalt oxide ore can be achieved in natural pulp when sodium sulfide is used as sulfurizing agent, butyl xanthate as collector, and vulcanization time of 4 min; when the magnetic field strength is of 1.1 T, flow rate of 1.0 cm/s and pulsation frequency of 16 Hz to operate magnetic separation of the tailings of copper-cobalt oxide ore after sulphidizing flotation, good magnetic separation effect of copper and cobalt can be obtained. For the raw ore containing 1.68% copper and 0.165% cobalt, with an oxidation rate of 94.05%, the open circuit test is applied with four phases of copper oxide flotation, three phases of cobalt oxide flotation and two phases of magnetic separation in selective operation and is obtained copper-cobalt oxide crude concentrate with yield of 20.99%, copper grade of 6.67% and recovery rate of 79.91%, cobalt grade of 0.396% and recovery rate of 51.70%. Copper-cobalt oxide crude concentrate is leached with sulfuric acid at 98% concentration to adjust the acidity of the leaching slurry. Under the conditions of liquid-solid ratio of 5∶1, leaching time of 4 h, stirring speed of 200 r/min, and terminal pH value of about 1.5, the leaching rate of copper is 97.96% and that of cobalt is 91.08%, and the net acid consumption per ton of copper is 0.96 t _acid/t _copper. The results of this paper can provide a technical reference for the smelting treatment of the same type of ore.