Study On Separation Performance Of Three-product Cyclonic Micro-bubble Flotation Column

With the increase of coal mining depth and the popularization use of heavy medium cyclone,the proportion of difficult-to-flotation fine coal slime in flotation feed is increasing, ultra-fineslime (-0.074mm) is increasing constantly. However, high-ash fine-0.074mm gangue particlestend to pollute the flotation concentrate by means of un-selective entrainment that theconcentrate ash couldn’t reach its standard. Cyclonic micro-bubble flotation column （FCMC）performed better separation effect than the flotation cell for ultra-fine coal, while it still exists theentrainment of slime with high ash content, resulting in a reduction the value of clean coal.Based on FCMC and three-product flotation column, a new experimental separating system—three-product cyclonic micro-bubble flotation column (3P-FCMC)—was designed in orderto improve separation effect of ultra-fine coal slime. Influence of the structure parameters (belowcolumn height and upper column height) and operating parameters (collector dosage, frotherdosage, pressure of circulation pump and froth thickness) on separation efficiency of3P-FCMCwere explored by single factor gradual optimization experiments. Then the optimum processparameters were determined. Optimum results with3P-FCMC and FCMC in separation of twotype of different coal slime were compared. The feasibility of concentrate ash reduction with3P-FCMC to guarantee product quality was explored.According to the results,3P-FCMC could obtain concentrate at lower ash and yield thanFCMC. In separation of coal slime from WangLou coal preparation plant, a decrease of1.56%and3.67%in ash and yield respectively was obtained mainly resulting from the decrease of-0.045mm particles (61.38%in proportion of shedding and27.03%in ash) and+1.80g/cm3particles (17.02%s and67.81%in each index) in concentrate. This trend was also obtained inseparation of coal slime from Huangyanhui coal preparation plant where clean coal ash and yieldwas1.25%and3.93%lower respectively and the shedding contained33.82%of-0.045mm sizefraction at an ash level of31.06%. Furthermore,-0.045mm particles in+1.50g/cm3clean coalfor WangLou coal slime of3P-FCMC was6.12%and3.75%lower in yield and ash than FCMCconcentrate respectively which proved less entrainment phenomena in3P-FCMC concentrate.3P-FCMC can reduce concentrate ash efficiently and is better flotation performance ofultra-fine coal slime than FCMC.