Study On Wettability And Floatability Of Different Rank Coal

Flotation is based on the nature of the mineral surface to achieve the difference between mineral and gangue separation of a physical chemical sorting method.In general,the stronger the hydrophobicity of the mineral surface,the better the floatability.The contact angle ? can mark the wettability of the coal surface.The wettability of the coal surface is of great significance to the coal flotation,coal dust and coal slurry preparation.The addition of surfactants in the water can effectively increase the wettability of water on the surface of the coal,thereby increasing the wetting efficiency of the coal.The addition of a small amount of surfactant in the process of coal flotation can improve the hydrophobicity of the coal surface,promote the dispersion of the collector in the pulp and spread on the surface of the coal particles,improve the flotation environment and enhance the flotation effect.In this paper,the coal with different metamorphic degrees in five areas was selected,and the coal samples were treated with different sandpaper to form different roughness on the surface of the coal sample.Then,different concentrations were obtained by using deionized water,glycerol and three kinds of surfactants.As the liquid to be measured,the contact angle of the surface ofdifferent roughness coal samples was measured,and the OWRK method was used to calculate the surface energy of different degree of metamorphism and different roughness coal to explore the different metamorphic degree.The difference of hydrophobicity and surface energy,the kind of surfactant,the concentration and the surface tension on the wettability of coal with different metamorphism.Then five kinds of coal samples were flotation test.During the flotation process,three kinds of surfactants were added to different concentrations of the solution,and compared with the flotation effect without adding surfactants,the effects of surfactants on flotation influences.The main conclusions of this paper are as follows:1.The contact angle of the deionized water on the coal surface increases with the increase of the degree of metamorphism of the lignite-coking coal,which indicates that the hydrophobicity of the coal surface increases with the increase of the degree of metamorphism.With the decrease of coal surface roughness,the contact angle increases with deionized water,and the hydrophobicity is enhanced,and the increase rate of coal with different metamorphism is inconsistent.2.The surface energy of the coal decreases with the increase of the degree of lignite-coking coal,that is,the surface energy decreases with the increase of hydrophobicity,and the surface energy of lignite is the highest,and the surface energy of coking coal is the smallest.The surface of the coal with the same degree of metamorphism,the surface with different sandpaper grinding,thesurface energy is also different,indicating that the surface of the coal after treatment with different sandpaper,the surface roughness of the coal surface energy.With the decrease of surface roughness of coal samples,the surface of coal can be decreased,which shows that the surface energy of coal decreases with the decrease of surface roughness.3.The same degree of deterioration of the coal,the surface roughness of the same,the same surfactant in its surface wettability is also different.Surfactant concentration in the CMC value,the wetting ability is better.With the increase of surfactant concentration,the surface tension gradually decreases,and its surface tension is no longer reduced when the concentration increases to the critical micelle concentration,and its wetting ability also does not change much.The same concentration of surfactant solution,the smaller the surface tension,the stronger the wettability.4.Different surfactants have different wetting ability,and the wetting ability of nonionic surfactants is higher than that of anions and cationic surfactants.The wettability of cationic surfactants is relatively poor.The surfactants of the anionic surfactant SDBS have better wettability than the nonionic surfactants OP-10 and the cationic surface activity of the coal with different degree of metamorphism.Agent DTAC,with the degree of deterioration of the increase in non-ionic surfactant OP-10 easier to wet coal surface.5.The addition of anionic surfactant SDBS,nonionic surfactant OP-10 andcationic surfactant DTAC promoted the flotation efficiency of five kinds of coal samples.The flotation rate and flammable Recovery rate has improved.6.Different surfactants have different effects on the flotation of coal samples.The adsorption effect of cationic surfactant SDBS on the flotation was the best,and the promoting effect of cationic surfactant DTAC was relatively weak.For Pang Pang coal and Dongqi coal samples,The effect of nonionic surfactant OP-10 on the flotation was the best,and the effect of cationic surfactant DTAC on the flotation was weak.For the Yangquan coal sample,the non-ionic surfactant OP-10 promoted the flotation Preferably,the anionic surfactant SDBS and the cationic surfactant DTAC have little effect on the flotation.