Study On The Effect Of Aeration Performance On The Coal Particle Size Of Inflatable Cyclonic Flotation Column

In the current flotation process, if the recovery of coarse particles is strengthed,which will result in more high ash fine slime entering into froth products.Finally,the ash of clean coal will be high. Oppositely, if the impact of fine slime on the clean coal ash is weakened, it will cause the loss of some coarse coal particles in the tailings.However, traditional flotation equipments are difficult to realize the effective separation due to their limitations.Combined with the advantages of cyclone flotation column and aerated flotation column, the influence of aeration performance on the particle size was studied. And the flotation kinetics of different granular slime was also explored.Experimental study on the coal slime flotation test in the inflatable cyclone flotation column is of great significance to improve the flotation effect of whole grain grade.The results show that the yield of 0.5-0.25mm particle slime was decreased gradually from bottom to top. While the 0.125-0.074mm and -0.074mm coal slime, the yield increased with the height of column. For the 0.25-0.125mm granular slime, the yield is not changed with the column height at low aeration, when the inflatable capacity reaches a certain degree, its yield fluctuates greatly with the height of the column, and the overall trend is increasing. The slime ash decreases with the increasing of the column height. The change of ash gradation in the flotation stage of the column is more severe than that of the middle and lower flotation segments. The greater the inflatable volume, the more obvious the change of the ash gradient. Analysis of clean coal screening results found when the filling capacity is increased from 0.25m3/h to 1.0m3/h,the proportion of 0.5-0.25mm and 0.25-0.125mm slime in the floating slime is increased from15.20 % to 39.35%, while the 0.125-0.074mm and -0.074mm slime increase quite slowly.The flotation kinetics test of different particle size coal slime was carried out in the inflatable cyclone flotation column. It was found that the increase of the aeration capacity could significantly increase the flotation rate constant of each grade coal slime,at the early flotation stage, the fine slime flotation has the fastest flotation speed, but with the extension of time, the coarse coal (0.5-0.25mm) floatability is better than fine-grained level, which also has a higher recovery. The separation efficiency of coarse coal slime in the aerated cyclone flotation column can be improved by increasing the amount of aeration.The results of the flotation kinetics for various size fractions in the cyclone flotation column were fitted. After the comparison of fitting models and experimental values, we can see that the coarse fraction size of -0.5+0.25mm, low aeration rate(0.25m3/h), complies with the first-order dynamic model, whereas the high aeration rate(1.0m3/h) accords with the second-order dynamic model. Under other aeration rate,-0.5+0.25mm coal slime is in line with the first-order rectangular distributing model.For -0.25+0.074mm and -0.5mm coal slime, the flotation process is in accordance with the second-order dynamic model(in addition to 0.75m3/h aeration rate is in line with the first-order rectangular distributing model). A new kinetic model suitable for describing the flotation process of each grade coal under different aeration rate was established. Its expression is:?t=??(1-e-t(1/4at3+1/3bt2+1/2ct+d)Where a, b, c, d are the relevant parameters in the above formula, and the model is highly reliable by analysis and verification.The separation efficiency of coal slime can be obviously improved by increasing the aeration capacity in the Inflatable Cyclonic Flotation Column, which can realize the effective recovery of coarse coal slime and have some reference significance for industrial application.