The Influence Mechanism Of Fluid Force Field On The Separation Of Cu-Ni Sulfide Ore

The problems of low nickel grade and recovery in nickel concentrate and the difficulty in magnesium reduction were discussed in the beneficiation process of copper-nickel sulfide ore.Pyrrhotite represents nickel sulfide minerals which been contained in copper and nickel sulfide minerals,and the dissolution and adsorption mechanism of metal ions on mineral surface,the adsorption of butyl xanthate on pyrrhotite surface,the dispersion/aggregation and heterogeneous condensation between pyrrhotite and serpentine under the action of fluid force field were investigated.The influence of fluid force field on mineral flotation process is revealed.Based on the investigation on the mechanism of magnetic enhancement of pyrrhotite by using Fe₃O₄particles as magnetite seed,the effects of fluid force field on the adsorption of sodium oleate on the surface of pyrrhotite,the surface composition and surface magnetic properties of pyrrhotite after magnetic enhancement were analyzed.The mechanism of the synergistic effect of fluid force field and magnetic field on the magnetic enhancement of pyrrhotite by magnetic seed Fe₃O₄ is revealed.By simulating the movement of single-phase fluid and solid-liquid two-phase fluid in the stirred tank,the velocity characteristics,shear force characteristics and turbulent kinetic energy characteristics of the flow field in the stirred tank are discussed.The flow field characteristics of the slurry and the dispersion characteristics of the particles under the effect of the fluid force field are revealed.On this basis,the“flotation-magnetic-flotation”combined with stirring tank pre-stirring process was developed to recover refractory copper nickel sulfide ore.It has important guiding significance for the efficient recovery of refractory copper nickel sulfide ore.The main research results are as follows:（1）Effect of fluid force field on mineral flotation separationThe change of process and structure parameters in the agitated tank can cause the change of mineral particles in the slurry under the action of fluid force field,it can promote the dissolution of Fe³⁺and Mg²⁺from mineral surface and adsorption on the surface of pyrrhotite,it also can change the surface potential of mineral particles,strengthen the function of minerals and agents,and improve the effect of minerals flotation;When the agitated tank is equipped with 4 baffles and upper straight/down inclined paddle,the mixing time is 30min,the mixing speed is 500r/min,flotation effect was the best,the recovery rates of monoclinal pyrrhotite,hexagonal pyrrhotite and serpentine were 82.9%,79.1%and 21.8%respectively;The action of fluid force field can increase the dispersion effect between mineral particles in pulp and the effect between mineral particles and agents,change the dynamic model of mineral flotation,and improve the effect of mineral flotation.（2）Synergistic effects of fluid and magnetic fields on mineral magnetizationFe₃O₄ particles can not magnetize serpentine and can effectively magnetize pyrrhotite,the magnetization intensity of saturated mass on the surface of pyrrhotite increased from 12.54Am²/Kg to 13.77Am²/Kg after magnetic strengthening,The study on the magnetic strengthening artificial mixed ore by the synergistic effect of fluid force field and magnetic field shows that:when the agitated tank is equipped with 4baffles and upper straight/down inclined paddle,the mixing time is 30min,the mixing speed is 500r/min,the magnetization p H is 9,the the dosage of sodium oleate is 3×10^-4mol/L,the magnetic field intensity is 160m T,the dosage of Fe₃O₄ particles and the mass of pyrrhotite were 1:10,the synergistic effect of fluid force field and magnetic field makes Fe₃O₄particles have better magnetic strengthening effect on pyrrhotite and its magnetic separation recovery is higher.Under the action of fluid force field,the adsorption capacity of sodium oleate on the surface of pyrrhotite was up to 0.761mg/g,and the composition content of magnetic species Fe₃O₄ which covered pyrrhotite particles surface was up to 2.91%,the magnetization intensity of saturated mass on the surface of pyrrhotite after magnetic strengthening was 13.79Am²/Kg,which was much higher than that of 12.87Am²/Kg when fluid force field was not added.The interaction between pyrrhotite,Fe₃O₄ particles and serpentine particles was calculated by extended DLVO theory:Under the action of magnetic field,magnetic agglomeration will occur between pyrrhotite particles,pyrrhotite and Fe₃O₄ particles at a spacing of 1～100nm;heterogeneous condensation occurs between pyrrhotite and serpentine at a spacing of1～5nm.When there is no external magnetic field,the addition of sodium oleate is not conducive to the aggregation of pyrrhotite and Fe₃O₄particles;when magnetic field is introduced,the addition of sodium oleate promoted the agglomeration effect between two particles.（3）Simulation of flow field in the agitated tankThe simulation results of single-phase fluid motion show that the number of baffles,blade type,layer spacing and rotating speed of agitating shaft in the agitated tank will affect the fluid surface motion,vortex height,velocity field,shear force and turbulent kinetic energy in the agitated tank;the simulation results of solid-liquid two-phase fluid movement show that:when the mixing simulation is conducted at 18.6s,the solid particles in the liquid phase are completely dispersed,and the solid-liquid two-phase fluid reaches a relatively stable state;the change of structure and process parameters in the agitated tank will affect the volume distribution uniformity of solid particles in the liquid phase;the intensity of turbulent flow in the agitated tank decreases with the increase of mineral particle size,density and volume fraction.Numerical simulation of solid particle group motion in the agitated tank shows that:with the increase of particle density,the number of collisions between particle clusters increases and the dispersion degree decreases.The dispersion and aggregation of particles can be affected by adjusting the structure and process parameters in the agitated tank.（4）Study on the mineral separation of Cu-Ni sulfide ore strengthened by fluid force fieldThe process mineralogy of Cu-Ni sulfide ore showed that the characteristics of nickel mineral dissemination are complex,disseminated grain size is fine,and the monomer dissociation is poor.Taking basic research as guidance in the earlier stage,a new combined process of"floating-magnetic-floatation"strengthened by fluid force field was developed for separation of nickel and copper from copper and nickel sulfide minerals.It compared with the original mixed flotation process,Cu and Ni in the tail of flotation can be further recovered by adding the magnetic separation process,in addition,pre-stirring is added before each separation process to effectively enhance the separation effect of each section by using the generated fluid force field,which effectively improves the mineral separation index.Nickel concentrate with Ni grade of 5.77%,recovery rate of 60.62%and Cu grade of 0.70%,recovery rate of 18.02%were obtained;Ni grade of 4.09%and recovery rate of 8.51%and Copper concentrate with Cu grade of 11.74%,recovery rate of59.73%were obtained.Compared with the original mixed flotation process,the total recovery rate of Ni was increased by 2.79 percent,the total recovery rate of Cu was increased by 3.04 percent,the Mg O content in nickel concentrate was reduced from 11.16%to 7.89%,and the quality grade of nickel concentrate was increased from level six to level five.Figures:128;Tables:44;References:164...