Flow Field Simulation Of Flotation Machine And Pulp Fluid Dynamics

At present flotation is one of the main methods of mineral separation.The flotation machine is the core equipment in the flotation process.The study on the relationship between the working parameters of flotation machine,flotation kinetics parameters and flotation indexes of flotation machine is helpful to improve the flotation efficiency.In this paper,by means of numerical simulation,the bubble layer in the inner flow field of the flotation machine is simplified,and the Eulerian multiphase flow model and the standard k-? turbulence model are proposed to simulate the internal flow field of the flotation machine.The model of single-phase flow,solid-liquid two-phase flow,gas-liquid two-phase flow were investigated under five kinds of impeller speed and aeration quantity.The relationship between the impeller speed,aeration parameters and pulp content,air dispersion rate of flotation kinetics parameters was explored.In this paper,the internal flow field and flotation kinetic parameters of XFD-II 1.0L flotation machine were studied:(1)According to the characteristics of the internal flow field of stirring type flotation machine XFD-II 1.0L and multiphase flow characteristics,ignoring the effect of foam layer on the flow field of the internal flow field of flotation machine is simplified,the basin is divided into the mixing zone,mineral transport area,gangue separation zone.(2)Under 500r/min,1000r/min,1500r/min,1900r/min,2400r/min impeller speed,the distribution characteristics of velocity of pulp flow in mixing zone,mineral transport area,gangue separation zone and the bottom of flotation tank was investigated,the velocity increases with the impeller speed.(3)The change of gas content and air dispersion rate in the bottom of the flotation cell and the free surface of the pulp were investigated under the 50L/h,100L/h,150L/h,200L/h,250L/h aeration.The content of gas in free surface increases with the aeration.Air dispersion rate remained at a high level in the early stage and decreased slowly with the increase of aeration,when the air flow is increased to a critical point to increase air dispersion rate decreased rapidly,and the critical point increases gradually with the impeller rotational speed.(4)Considering the pulp gas content and air dispersion rate,the suitable working parameters of XFD-II 1 L flotation machine is impeller speed 1900r/min and chargevolume 250L/h.Through the actual laboratory flotation verification,the selected flotation machine work parameter is reasonable,and it has the project practical application significance.(5)The effects of different working parameters on distribution characteristics of scheelite,fluorite and calcite near the bottom the flotation tank and the free surface of the pulp was investigate.Considering three kinds of mineral density differences,from1700r/min to 1900r/min impeller speed,scheelite content is higher relative to the other two kinds of minerals in the upper part of the transport area and separation zone,the collision probability with the bubble is higher too.Through laboratory tests of pure minerals flotation of scheelite,Scheelite content in the upper part of pulp flow of the numerical simulation results and the content of the actual scheelite flotation recovery rate are agreement.And the optimum conditions of scheelite separated with calcite and fluorite is the impeller speed 1900r/min,aeration rate of 250L/h.