Study On Surface Oxidation Electrochemistry Of Copper And Nickel Sulfide Ore

For pentlandite and chalcopyrite are embedded in close symbiosis, both have similar flotability and the surfaces are easily oxidized which result flotability fallen and difficult separation, while nickel recovery rate is reduced for part of nickel in the process of conventional high alkali nickel flotation separation of copper nickel minerals into copper concentrate, falling of nickel and copper in nickel concentrate ratio, therefore it is of great significance to improve the resources utilization through researching the surface oxidation process and mechanism of pentlandite and chalcopyrite. This paper contrary to the surface oxidation electrochemical mechanism influence factors such as p H, presence of collector were investigated and the main contents are as follows:(1) From the surface oxidation Eh-p H analysis, we could infer the trend of surface oxidation and sulfide minerals of pentlandite and chalcopyrite, combined with the collectorless cyclic voltammetry tests results, their surfaces properties and flotability of the two kinds of sulfide ore were determined by oxidation degree. Sulfide ore behaved collectorless flotability when the surface was moderate oxidized for its product hydrophobic elemental; while flotability fell sharply or float when it oxidized depth that produced metal hydroxide and metal sulfate.Under the condition of high p H and potential, depth oxidation was easily occured on the surface of sulphide.(2) Tafel curves showed that p H value the corrosion kinetics parameters, chalcopyrite had more negative corrosion potential and bigger corrosion current density which corrosion occurred more often than pentlandite under the same p H collectorless condition(3) The open circuit potential and electrochemical tests of pentlandite and chalcopyrite under xanthate collector conditions showed that hydrophobic dixanthogen were the anode oxidation production, and it also showed that with the addition of collector, the oxidation process on the surfaces of sulfide minerals were greatly enhanced, made the oxidation rate far outweigh than the oxidation rate of sulfide ore themselies. The hydrophilic metal hydroxide and hydrophilic metal sulfates would be produced and covering the mineral surfaces, blocking the formation of dixanthogen and reducing flotability when the sulphide ore flotation p H was higher than the the critical p H and strong surface oxidation was dominated.On the other hand,within the critical p H, thedixanthogen generated response would be dominated and made mineral surface hydrophobic buoyant for its adsorption on mineral surface.(4) Electrochemical kinetics study of sulfide minerals showed that under the same collector concentration and p H condition, thickness of the collector oxidation generated production, hydrophobic dixanthogen, was different on sulfide mineral surface, which lead to hydrophobic differences and, in turn,affected the flotability of sulfide ore.