The Research Of Electrolytic Bubble Characteristics And Its Effcet On Slime Flotation

Slime flotation technology research has been a hot and difficult coal industry.Slime has "small,complex,difficult" characteristics·The finer the particle size is,the larger the surface area and surface energy are,the low selectivity and the high consumption of the drug is,these reasons explain low efficiency of flotation of fine particles between the particles and bubbles due the collision probability is low.Reducing the size of the bubbles can increase the probability of collisions of bubbles with particles and combustible material to improve the rate of recovery of flotation.electrolytic bubbles has been used to study a variety of mineral flotation,due to its small size and high concentrations and dispersion,flexible adjustment of bubble diameter(through change the electrolyte parameters,select the appropriate electrode geometry and adjust the required pH of flotation medium)and high physical chemistry activity.This paper investigate the effect on inflatable amount and bubble size of different conditions-different electrolyte in the aqueous medium(NaCl,MgCl2,AICl3,Na2SO4,MgSO4,Al2(SO4)3),different current density,different electrolysis time and different electrolyte concentration.Analysis of the mechanism of electrolytic bubbles is through the method of measuring surface tension changement.Coal is 8#coal from Malan CPR.On the basis of analysing its basic properties,electrolytic flotation is investigated through adding chloride and sulfate.A preliminary study from the mechanism is have done by using infrared analysis,contact angle analysis,and Zeta potential analysis.The following conclusions are obtained:(1)Aeration of all electrolytic solution increase with the incresment of anodic current density,and increased first and then decreased with the incresment of electrolytic concentration-the optimal electrolyte concentration of chloride is 1g/L.Optimal electrolyte concentration of sulfate is 0.5g/L,and increased first and then decreased with with time-the optimal electrolyte time of MgCl2 and Al2(SO4)3 is 15min,the others is 25min;MgCl2 solution inflate best when the time is 15min.Na2SO4 solution inflate best when the time is 25min.Inflatable amount:magnesium salt and sodium solution>aluminum salt.(2)Increasment of anode current density increase-45?m bubble quantity but reduce 45-125?m bubble quantity.For sodium,small bubble quantity is generally increases with the increasment of electrolyte concentration,but the aluminum is in contrast;for MgSO4 and MgCl2,small bubbles quantities are slightly increased with electrolyte concentration increased.Maximum number of-45nm bubbles is of AICl3 and Al2(SO4)3 solution of 0.25g/L.The relationship of bubble size and time has the same conclutions(3)Small surface tension form bubble easily,the maximum inflatable amount is present in the extreme points of surface tension,but the surface tension is not the only factor that determines the amount of inflatable amount.(4)Compared with chloride,sulfate solution can obtain a greater yield of clean coal.Aluminum has a better ash reduction effect than sodium and magnesium salts.From the perspective of bubble size,with the incresment of electrolyte concentration,the better flotation results corresponding to the bubble size range decreases.Whether it is the recovery of combustibles or improved floatation index,flotation effect of sulfate is better than chlorine salts.(5)By infrared analysis,contact angle analysis,laser particle size analysis,as well as the Zeta potential analysis,the results can be drawn:the coal sample after electrolytic pretreatment,on the one hand,the coal surface—OH,>C=O,—COOH oxygen functional groups reduction in the coal sample and contact angle larger,indicating that coal sample enhanced hydrophobic.The interaction of coal and air bubbles in the flotation process optimize the flotation effect and reducing the Zeta potential of coal surface,making coal and collecting agents have better effect and flotation activity improved.It can be seen through the test results and analysis:the electrolytic treatment can make certain change to the surface properties of coal.