Numerical Simulation Of Bubble And Pulp Flow Features In KYF Ⅱ-40Flotation Machine

Abstract:In the process of mineral flotation, bubble velocity, gas holdup and bubble size distribution in flotation cell affect the flotation efficiency directly. This paper summarizes the research status of froth flotation and multiphase flow, applied numerical simulation method to study the bubble and pulp flow features in flotation cell. Major research work and conclusions are as followed:1、In view of the existing numerical simulation model, it is difficult to obtain the flotation bubble size distribution. Population balance model is put forward to describe flotation bubble size and its changes, coupled with Euler model and applied to numerical simulation of gas and liquid two phase flow movement in flotation cell. Euler-PBM (population balance model) model adopts Luo&Lehr breaking model to describe the broken process of bubble, and modifies Prince&Blanch coalescence model to describe the coalescence process of bubble. The result of simulation experiment applied with experimental data shows that Euler-PBM coupling model can simulate bubble and pulp in flotation machine flow features correctly.2、This paper applied Euler model and Euler-PBM coupling model in numerical simulation of bubble and pulp flow process in KYF Ⅱ-40flotation machine of a alumina plant on the production condition in hand respectively. The result of Euler-PBM coupling model numerical simulation such as flow field characteristics and gas holdup are closer to reality. In addition, Euler-PBM coupling model could describe bubble size and its change process, and predict the distribution of bubble size.3、Single factor method has been applied to investigate five aeration speed and five stirring speed. The change of air velocity features, gas holdup and bubble size distribution in KYF Ⅱ-40flotation cell. The results showed that, keeping the stirring speed is constant, with the increase of aeration speed, the turbulence intensity of flotation cell is aggravated, while gas holdup is increased, bubble size is growing larger firstly, and then becomes smaller. Keeping the aeration speed is constant, with the increase of stirring speed, the turbulence intensity of flotation cell is aggravated, air dispersion is getting better and better, bubble size decreases gradually.4、The air velocity features, gas holdup and bubble size distribution in KYF Ⅱ-40flotation machine are investigated for the situation of8m/s aeration speed and136r/min stirring speed. The results show that under the those conditions, air velocity features, gas holdup and bubble size distribution in KYF Ⅱ-40flotation cell are all improved compared to the kept rated condition. The best parameters of KYF Ⅱ-40flotation machine are taken to be the aeration speed of8m/s and the stirring speed of136r/min respectively.