Study On Centrifugal Filtration Of Flotation Clean Coal Based On Hydrophobic Agglomeration

In this paper,the dewatering process of flotation clean coal with hydrophobic agglomeration and centrifugation filtration is proposed.Taking the flotation clean coal of Xiaoyi Xingyang coal preparation plant as the object,the filtration dehydration test was carried out by high-speed stirring device and centrifugal filter device,and the influence of the agglomeration agent addition system and stirring system on the dewatering effect was discussed.The hydrophobic agglomeration was carried out with diesel and heavy oil as agglomerating agents.The single factor optimization test was carried out with the agglomerated oil addition system and the mixing system as the investigation factors.The water content and recovery rate of the product after dehydration were the process indicators,and the factors were analyzed.The effect of the hydrophobicity of the coal particle surface and the agglomeration effect of the particle results in the following conclusions:The best condition for diesel as agglomerating agent:3% of diesel fuel,the first stirring speed and time are 1500r/min and 14 min respectively,and the second deceleration stirring speed and time are 750r/min and 2.5min respectively,the water content is 21.56% and the recovery rate is 96.06%.The best condition for heavy oil as agglomerating agent:9% of heavy oil added,the first stirring speed and time are3000r/min and 18 min respectively,and the second deceleration stirring speed and time are 1500r/min and 2.5min respectively,the product moisture is 16.02% and the recovery rate is 93.95%.By counting the particle size distribution of flocs under different conditions,it is found that with the increase of the addition amount,the floc size increases continuously,and the diesel has better effect on the fine particles.The particle size of the floc increases with the increase of the single-stage constant-speed stirring speed,and the stirring speed is too high,which is not conducive to the formation of the floc.The amount of fine particles is significantly reduced as the single-stage constant-speed stirring time is extended.The second-stage deceleration agitation is better than the single-stage constant-speed agitation on fine particle agglomeration and improved recovery.The influence of stirring speed on the mixing effect and the calculation of thetotal potential energy between the oil bead and the coal particles were simulated.The conclusions were as follows:(1)When the stirring speed is less than 1500r/min,the mixing effect will improve with the speed;the stirring speed is more than1500r/min,the mixing effect did not change,but the shear force became stronger and was not conducive to the formation of the floc,which was consistent with the test results.(2)Under the action of hydrophobicity,the total potential energy decreases with the distance decreases between the oil beads and the coal particles,and the oil beads adsorb and spread on the surface of the coal particles.