Study On The Effect And Mechanism Of Hydrophobic Particles On The Flotation Behavior Of Fine Low Rank Coal

As a non-renewable resource,coal plays an important role in China's economic construction and development,and is of great significance to human survival and progress.China has rich reserves of low-rank coal resources,and its output accounts for about 40%of the total coal output.It is an important part of coal energy production and supply.As the degree of coal mining mechanization increases,the low-rank slime content gradually increases.The low-rank coal has many oxygen-containing functional groups and poor floatability.Flotation has outstanding problems such as high reagent consumption and low process efficiency,especially at the fine particle level.In view of this,this paper investigates the effect of hydrophobic particles on the flotation behavior of fine low-rank coal,explores the influence of hydrophobic particles on the flotation mechanism of fine low-rank coal,and builds a theoretical system for the analysis of low-rank coal reinforced by hydrophobic particles.Low-rank coal efficient flotation provides theoretical and technical support.The analysis of the test samples shows that the main particle size of the test coal sample in this paper is-0.074mm,the ash content is 22.59%,and the fine coal slime component content is high;the main gangue components are quartz and kaolinite,the surface is rough,there are a lot of cracks,And contains a variety of oxygen-containing functional groups,such as:-OH,C=O,RO,-COOH,etc;the contact angle is 48.54°,the hydrophobicity is weak,the floatability is poor,and the high-order coal,polypropylene,and ferric oxide particles The contact angles are 79.35°,101.91°,and 131.90°,and the floatability is good.The experimental study on the influence of hydrophobic particles on the flotation behavior of fine low-rank coal showed that the best flotation conditions in the experiment were agitation strength 1800r/min,flotation concentration 60g/L,collector dosage 3000g/t and foaming agent The dosage is 400g/t.Under this test condition,the recovery rate of combustibles of low-rank coal is 50.88%;with the increase of the proportion of hydrophobic particles,the recovery rate of combustibles of fine low-rank coal is increasing;for the three types of hydrophobic particles,medium-sized hydrophobic particles Is better than other particle sizes;using the classic two-stage flotation kinetic model as the fitting model for this experiment.When hydrophobic particles are added,the flotation rate of fine low-rank coal is significantly increased.Among the three types of hydrophobic particles,The addition of medium-sized hydrophobic particles has the fastest flotation rate.The study on the mechanism of hydrophobic particles affecting the flotation of fine low-rank coals.The results show that the hydrophobic force plays a leading role in the adhesion behavior between the particles during the flotation process,and the fine low-rank coals and particles are always maintained at a large distance.The tendency of mutual attraction;agglomeration occurs in the analysis of laser particle size and scanning electron microscope;in the solution phase,the merger time between the two phase bubbles is 0.880s,and the merger time sequence after the single particles are attached to the bubbles is:low order Coal<high-rank coal<polypropylene<ferrous oxide,can increase the merger time of bubbles after adding hydrophobic particles in the fine low-rank coal;the higher the proportion of hydrophobic particles added,the greater the viscosity increase,the more the liquid membrane discharge rate Slower,the foam half-life will also be extended.In addition,the finer the hydrophobic particles added,the more the viscosity increases,and the longer the half-life.Hydrophobic particle recovery and reuse test research results show that in the hydrophobic particle recovery and reuse test,when high-order coal is added,no material separation is required;when adding polypropylene particles in flotation,the density difference can be used to use a centrifuge Separation,but the separation rate is relatively low,only over 75%;when flotation of ferric oxide particles is added,magnetic substances can be recovered by magnetic separation,and the recovery rate is as high as 99%.To sum up,the flotation index is the best when adding high-order coal,but in the mechanism analysis,polypropylene feed and Fe₃O₄have more influence on the flotation of low rank coal.In addition to high-order coal flotation,there is no need to separate the flotation products,so that the hydrophobic particles can become the clean coal part,reduce the ash content of the clean coal,improve the yield of the clean coal,and thus improve the overall effect of flotation.Therefore,in the flotation of fine-grained low rank coal,the use of high-order coal as the particle flotation has the advantage of high recovery.In addition to polypropylene and ferric oxide,hydrophobic particles can be used Particles can be reused to reduce material loss.