【作者】 喻明军；

【导师】 王毓华；

【作者基本信息】 中南大学 ， 矿物加工工程， 2010， 硕士

【摘要】 针对铝土矿反浮选脱硅中存在的微细粒浮选效率低的问题,本文设计了一种较适合于铝土矿微细粒反浮选的充气式深槽浮选机,并对河南铝土矿进行了反浮选试验。论文系统考察了浮选机工艺参数对反浮选指标的影响规律,在最佳浮选机工艺参数下考察了深槽对微细粒的浮选效果,利用正交条件试验确定了试验相关因素的影响因子。采用FLUENT软件模拟浮选槽内部流体特性,结合空气分散度测定,验证分析浮选试验结果和模拟结果。反浮选试验结果表明：浮选机最佳充气量为200-250L/h,最佳转速为2000-2200rpm；浮选槽深度的增加有利于铝土矿的反浮选过程。槽深由131mm增加到177mm时,在精矿铝硅比相近的前提下,精矿Al2O3回收率由73.41%增加到77.99%。利用正交条件试验的R值和F值检验可知,调整浮选机转速对浮选精矿铝硅比和回收率影响较大；深槽不但有利于提高浮选回收率,而且能很好的控制尾矿铝硅比。表明充气式深槽浮选机能提高微细粒的浮选效果。基于FLUENT的流体特性模拟结果表明：随着浮选机充气量的增加,空气分散度增高,但当充气量高于一定水平时,空气分散度下降。提高浮选机转速有利于槽内气体分散,增强紊流作用,转速为2000rpm时浮选槽内流体特性最好,但转速过高,槽内紊流性变差,不利于浮选。浅槽时,槽内流体波动较大,槽表面不稳定,增加槽深,形成平稳的浮选区域(泡沫区和分离区),槽表面变稳定,槽内流体特性变好,深槽比浅槽有利于浮选。深槽条件下,槽内负压变大,浮选机需要的轴扭矩增加,对比144mm槽深模拟结果,浮选机最佳充气量由250L/h增加到300L/h,最佳转速由2000rpm增加到2200rpm。空气分散度测量结果与反浮选试验结果及模拟结果都相符合。更多还原

【Abstract】 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.更多还原