Research On Magnesium Decrease In Copper-nickel Sulfide Ore Floatation

Nickel is one of the strategic reserve resources in many countries,With the development of economy,there is a great dependence on external of nickel resources in China,and an increasing contradiction in the supply and demand is rising.Jinchuan company as a typical representative of copper-nickel sulfide ore in our country,the gangue minerals are mainly magnesium-containing silicate minerals in the raw ore,so it is of great significance to reduce the content of MgO in the concentrate through flotation.In this paper,the complexing agent is first used to clean Cu²⁺and Ni²⁺ions on the surface ofmagnesium-containing gangue minerals,the appropriate depressor is added to expand hydrophilic difference between the objective minerals and gangue minerals,so as to improve the grade and recovery rate of copper and nickel in concentrate and reduce the content of MgO.In the flotation of practical ore from Jinchuan company,in which the grade of nickel and copper are respectively 1.28%?0.86%and the content of MgO is 28.61%,the final copper-nickel mixed concentrate with Ni grade of 9.03%,Cu grade of5.18%,MgO content of 6.18%,nickel recovery of 85.30%,copper recovery of 72.82%was obtained,on the basis of single factor test to determine the best flotation conditions,under the reagent system of citric acid-modified starch combination,through the closed-circuit flotation process of one roughing-two selecting-three scavenging,and middlings returning in proper order into the flow.The results of XRD show that,the main mineral components are pentlandite and chalcopyrite in the concentrate and serpentine and chlorite in the tailing,which indicates that the gangue minerals can be effectively suppressed and the objective minerals can get effectivelyenriched.The flotation results of single mineral show that,addingxanthate has not much affect for the flotation of serpentine,while Cu²⁺can activate the flotation and citric acid can eliminate it,modified starch can reduce the recovery rate of serpentine;the recovery rate ofpentlanditecan reach more than 90%in the flotation of single pentlandite mineral by using butyl xanthate as collector,while it may be significantly reducedwith a little amount of serpentine,and it can be improved by increasing the amount of butyl xanthate or reducing the pH or adding the modified starch.The calculation resultsof solution chemical indicate that,citric acid can eliminate the activation to serpentine of Cu²⁺Ni²⁺by generating stable complex compound and going into the solution.Under the flotation pH environment of copper-nickel sulfide ore,serpentine and pentlandite may produce electrostatic adsorption for the electric property difference;citric acid and modified starch can both reduce the Zeta potential of serpentine and pentlandite,make the both beelectronegativity,so as to eliminate the electrical phase variations caused by electrostatic adsorption.Infrared spectrum analysis showed that modified starch can adsorp on the surface of serpentine mainly through the effect of hydrogen bond.