High-Efficiency Flotation of Fine Particle Coal by Nanobubble and Its Mechanism
The traditional flotation with the large volume and small specific surface area of bubbles results in the.low flotation efficiency of fine particle coal,which brings great difficulties to the recovery of fine particle coal.The difference between nanobubble flotation and traditional flotation on the recovery of fine particle coal were compared,and the influence of nanobubble on the flotation of fine particle coal were explored by means of flotation condition test,flotation kinetics test,screening test and Zeta potential test.The research results are drawn as follows.The introduction of nanobubbles can improve the recovery rate of fine particle coal and show good flotation selectivity.In the same flotation time,the recovery rate of clean coal by nanobubble flotation is always higher than that by traditional flotation,and the flotation operation can be completed about 40 s earlier than that by traditional flotation,which effectively improves the flotation rate.When there are nanobubblcs,with the decrease of the particle size of the clean coal product,nanobubbles show a more efficient recovery effect on fine particle coal.In the range of-0.043 mm fine particle coal,the recovery of the clean coal by nanobubble flotation is 16.33 percentage points higher than that by traditional flotation.Nanobubbles can effectively reduce the surface potential of coal particles,effectively reduce the electrostatic repulsion among coal particles,enhance the stability of the hydrophobic agglomeration structure of fine particle coal to improve the recovery effect of fine particle coal.The nanobubbles can increase the contact angle of coal surface by 9.23°,which effectively improves the hydrophobicity of coal surface.
NanobubbleFine particle coalFlotation mechanismRecovery rate of clean coal
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