Numerical Simulation Of Microbubble Flotation Technology

Firstly, the history and state of research and application of flotation column and micro-bubble are discussed systematically, and the work principle, the advantage and disadvantage of several typical flotation column and micro-bubble generator are narrated also. Meanwhile, the research state of effect theory of bubble and particle is expounded, too.According to fluid dynamics, the mechanism of the air entrained by a jet and the bubble formation are analyzed, and the basic performance equation of jet micro-bubble generator is set up. Moreover, the relationship equation among the structure parameters of micro-bubble is deduced. The research expresses that the air velocity becomes smaller with the pressure of mixed pipe entrained and there is an optimal value of mixed pipe that makes the air velocity become greatest.In accordance with the force of particles, based on the maximal adhesive force, the force mechanism of micro-bubble mineralization in four cases (single particle adhesion, multi-particle adhesion, single layer particle adhesion, multi-layer particle adhesion) is studied. The research indicates that there is an important influence from contact angle, micro-bubble diameter, mineral diameter and property, and maximal coverage angle to micro-bubble mineralization. The property of mineralization micro-bubble (micro-bubble diameter and density) is deduced, too. The results have an instructive effect for flotation design.Based the multi-phase flow model, with the help of FLUENT, this thesis systemicly analyses the flow field of micro-bubble generator in different diameter exiting and angle entraned of nozzle, pipe entrained diameter, ratio of area, distance between nozzle and mixed pipe, ratio of length and diameter, subulate angle of diffused pipe, coupling type of ventricle entraned, micro-hole baffle, velocity and chroma of nozzle entraned, and back pressure exiting. Furthermore, the optimal design is made under the instruction of simulation results. Meanwhile, the flow field of micro-bubble being optimal is analyzed in different bumper wall.Lastly, by the experiment, there is very close relationship among slurry pressures, work back pressures, the distance between mixed pipe and nozzle, the ratio of length and diameter and flotation performance. The simulation result is in agreement with the experiment. At the same time, the flotation experiment is completed on the micro-bubble generator which is designed by us. The selection of this thesis comes from the natural science fund in Yunan province. The research result has some meanings in developing micro-particle flotation equipments.