Research On Structural Optimization Of Centrifugal Flotation Machine Based On Numerical Simulation

Self-priming centrifugal flotation machine breaks the traditional mechanical flotation design, gives full play to the turbulent jet, and combines centrifugal force field and gravity field, etc.. It is unique in feeding mode, pulp inflatable, bubble mineralization and slurry flow, and makes progress in high speed and efficiency flotation. Self-priming centrifugal flotation machine design met the concept of "Dynamic mineralization and static flotation”,also achieved good performance in industrial test and production. There exists a variety of mineralization processes in centrifugal force field flotation device, which can improve the separation efficiency of fine particles effectively. In recent years, centrifugal flotation machine were studied by scholars, and gradually be extended, and has been used in metal and non-metallic mineral recycling, water purification, medicine, environmental protection and other fields.In this paper, the CFD software, STAR CCM+, was used to simulate centrifugal flotation machine whole flow field and bubble generator structural optimization, and critical parameters including velocity, pressure, gas-liquid holdup, turbulent intensity distribution and inspiratory capacity were obtained. The simulation results show that: flow and pressure of the annular device outlet maintain uniform, which is conducive to the stability of pulp and foam layer. There is a loss of energy, mixture efficiency and other issues in bubble generator, due to structural factors, such as mixing chamber, nozzles, or throat. High velocity gradient existed in outer flotation cell, from 7-8m/s down to 1m/s or less radially inward, could lead to level deflection and flipped. The dispersion of mineral laden bubbles in outer cell was relatively low, and at the initial stages it was only 20%-30%,increased with the Z axis increases.The analysis of simulating different guiding device structure showed that, when adding rotating baffle or deflector, it could effectively reduce the outer cylinder velocity gradient and improve dispersion in the initial stage; while the concentrate loss increased,with adding to the vertical baffle. The simulation results indicated that with other parameters unchanging, inspiratory capacity and Turbulent Kinetic Energy decreased by increasing nozzle outer diameter, and the better nozzle diameter was 19 mm. Inspiratory capacity and negative pressure of throat decreased by increasing area ratio, velocity of diffuser outer reached the maximum at area ratio 3.57. The simulation results demonstrated that the optimum area ratio was 3.57, which could provide a reference for optimizingstructure of centrifugal flotation machine and bubble generator.