细颗粒煤炭纳米气泡高效浮选及其机理研究

High-Efficiency Flotation of Fine Particle Coal by Nanobubble and Its Mechanism

传统浮选气泡体积大、比表面积小,导致细颗粒煤的浮选效率低,给细颗粒煤的回收带来极大的困难。对比了纳米气泡浮选和传统浮选对细颗粒煤回收的差异,通过浮选条件试验、浮选动力学试验、筛分试验、接触角及Zeta电位测试等手段探究了纳米气泡对细颗粒煤浮选的影响。结果表明:纳米气泡的引入可以提高细颗粒煤的回收率,并表现出良好的浮选选择性;在相同的浮选时间内,纳米气泡浮选的精煤回收率总是高于传统浮选的精煤回收率,并且纳米气泡浮选较传统浮选提前约40 s就可完成浮选作业,有效地提高了浮选速率;有纳米气泡时,随着精煤产品粒度的减小,纳米气泡对细颗粒煤表现出更高效的回收作用,在-0.043 mm的细颗粒煤的范围内,纳米气泡浮选精煤的可燃体粒级回收率高于传统浮选16.33个百分点;纳米气泡可以有效降低煤颗粒表面的电位,降低煤颗粒之间的静电斥力,增强了细颗粒煤的疏水性团聚结构的稳定性,进而提高了细颗粒煤的回收效果;纳米气泡可以提高煤表面接触角9.23°,有效改善煤表面的疏水性。

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 40searlier than that by traditional flotation,which effectively improves the flotation rate.When there are nanobubbles,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-0.043mm fine particle coal,the recovery of the clean coal by nanobubble flotation is 16.33percentage 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.