Analysis Of Gas-liquid Dispersion Characteristics And Factors Of KYF-0.2 Flotation Machine By CFD Method

KYF-0.2 flotation machine,which uses the separation method of the interaction between bubbles and particles,is widely used in mineral processing industry.External air compressor sends the air into the domain of mixing impeller through the hollow shaft of the flotation machine.And Then the rotation of the mixing impeller provides a strong radial flow,which leads the gas through the stator turbulence and distributes the gas to the entire flotation tank.In this paper,the steady and transient calculations are carried out for the KYF-0.2 flotation machine,with standard k-? turbulence model,Eulerian-Eulerian multiphase flow model,and multiple size group(MUSIG)model.The particle transport model is used for the slurry particles.Considering the positional relationship of geometry of the stator and the rotor,the reasonable time steps are selected.The rationality of the model has been verified by comparison of experimental stirring power consumption with simulated value.Concentrated on the gas-liquid dispersion problem,based on the actual field background,an effective method for analyzing and evaluating the gas-liquid flow characteristics in the flotation cell is obtained,and the factors affecting the gas-liquid dispersion of the flotation machine are explored.The simulation results of different air intakes show that:the stirring power consumption is more obvious when air intake is more than 10m3/h.Increase of the air intake makes the interaction between the impeller and the stator weaken,causes the large-sized bubble area gradually to expand,lets gas jet angle increase significantly,and gives rise to the strengthening of the lower circulation effect of the flotation cell and the weakening of the upper circulation effect.The simulation results of different rotation speeds show that:when the rotation speed increases,the gas phase gradually approaches from the center of the flotation cell to the annular wall,the bubble size increases,and the gas jet angle decreases,the lower circulation effect in the flotation cell is weakened,and the upper circulation effect is strengthened.Three factors affecting the gas-liquid dispersion of flotation machine have analyzed.As the thickness of impeller increases,the stirring torque value of the impeller decreases significantly,and its fluctuation amplitude also decreases.Air holdup in the domain of impeller increases,the difficulty of the gas phase flowing out around increases,and the range of the blade's work on the liquid phase decreases with the thickness of impeller increases.The flow rate of the slurry increases,the up and down circulation of the liquid phase decreases,the gas phase does not change,and there is a "short circuit" effect.As the solid phase concentration increases,the ability of the ore particles entering the tank to reach a longer residence time decreases,the lifting angle of the gas phase increases,the upper circulation area decreases,and the overall flotation mixing effect reduces.Gas-liquid dispersion characteristics and influencing factors of the flotation machine is analyzed by CFD method,which can provide an effective reference for the flotation production operation,equipment maintenance and other mineral processing equipment experiments and R&D design.