Experiments And Simulation On Performance Parameters Of Deep Pneumatic Flotation Machine

In order to solve the problem of low efficiency for fine particles flotation in reverse flotation of bauxite ore, a deep pneumatic flotation machine was designed to improve the flotation effiency of ultra-fine particles for bauxite reverse flotation, and experiments of this flotation machine were also systemetically carried out in reverse flotation for Henan bauxite resources.The influences of flotation machine performance parameters on the separating efficiency were studied to get the optimal parameters. Then the effects of cell-depth on the fine particles flotation were investigated under the optimal parmeters, and the relative effect factors were also determined by orthogonal test. The fluent softawre was uesd to simulate fluid characteristics inside the cell. Combining the measurements of air dispersion, the result of the flotation experiments and simulation was verified accurately.The results show that the best flotation aeration rate is between 200-250L/h, the optimal rotation speed is between 2000-2200rpm.The increase of cell depth is benefitial to the reverse flotation of bauxite ores. On the premise of the similar concentrate grade, the recovery of Al2O3 in concentrate improved from 73.41% to 77.99% when the cell depth increased from 131mm to 177 mm. The vlues of R and F in the orthogonal test show that rotation speed has a great effect on the ratio of Al/Si and recovery of concentrate. Deeper cell can not only increase the flotation recovery, but also can control the ratio of Al/Si of the tailings. In a word, the deeper pneumatic cell can greatly promote the flotation efficiency of ultra fine particles.The FLUENT software stimulation shows that the air dispersion increases with the increase of gas flow. However, when the gas capacity goes above a certain point, the air dispersion decreases. With the rotation speed increasing, the air dispersion and the turbulence both increase. The optimal fluid characteristics happened at the rotation speed of 2000rpm. If the rotation speed goes higher continually, the turbulent effect increases, and then the flotation perfomance goes worse. The fluid is fluctuate and the cell surface is not stable for shallow cell. When the depth of cell increases, a stable flotation zone (bubble zone and separation zone) is formed, and the fluid characteristics is getting better. Hence, the deep cell represents better flotation perfomacne than the shallow one. For the deep cell, the negative pressure is getting bigger, thus the bigger axle torsion is needing. Compared to the standard cell (h=144mm), the best aeration rate is varifing from 250 L/h to 300L/h and the best rotation speed is changing from 2000rpm to 2200rpm for deep cell. The measuremnts of air dispersion accord well with the results of FLUENT stimulation, which shows the accuracy of the stimulation results.