Study On The Wettability Of No.4 Coal In Dafosi Coal Field

Coal wettability is a kind of ability of coal to adsorb liquid,and its wetting effect is far-reaching in production life.For example,coal dust generated in coal mining,with ordinary aqueous solution to reduce the efficiency of poor spray,because the poor wetting of coal,water is not easy to wet.Understanding the wettability of coal in the study area and finding a surfactant that can change the aqueous solution is a great help to mine production.In this paper,the coal quality of the study area is studied.According to the results of coal petrography analysis and proximate analysis of coal,it is concluded that the NO.4 coal is Non caking coal.It belongs to the ultra low ash and medium and high volatile bituminous coal.Compared with the same type of coal,the water and fixed carbon content of the coal are relatively high.It was found that the carbon content of the NO.4 coal was higher than that of the same grade of bituminous coal,the content of oxygen was 10.15%,the content of hydrogen was 4.75%,the content of nitrogen was 0.83%,the content of carbon in the Vitrain((83.16%),while the remaining hydrogen elements,oxygen elements,carbon content,Vitrain are greater than the Durain;Secondly,the pore characteristics and specific surface area of coal were studied.The Mercury injection experiment and Liquid nitrogen adsorption test results show that the specific surface area of Vitrain of NO.4 is larger than that of Durain,and the specific surface area of NO.4 coal is between Vitrain and Durain.The pore volume,Average pore throat radius is larger than that of Durain.Compared with Durain,the separation property of Vitrain is worse,the distribution of hole is uneven and coarse,and the overall connectivity is not good.The surface of the Vitrain is limited by the debris,leading to the poor connectivity between the crumbs;and the presence of kaolinite on the surface of the Durain,and has a vertical tensile fracture,so that the overall quality of the connection is excellent.Both the Vitrain and the Durain contain a small amount of ink Bottle hole(fine bottle hole);Finally,the wettability was measured.The contact angle of the contact surface of coal water(distilled water)shows that the contact angle is from the following:Durain surface<vertical stratification surface<oblique bedding surface<parallel bedding surface<Vitrain surface,nonionic surface active agent 6501 solution concentration of 1.6%,the parallel stratification,vertical bedding,oblique bedding,Vitrain surface and Durain surface contact angle are reduced to about half of the original;Reversal agent g502 solution concentration of 0.1%,the contact angle can be increased to about 1.6 times the original;wetting effect does not increase with the addition of wetting agent solution concentration increases linearly,but will be in a certain Concentration range of critical micelle concentration(CMC),when added wetting agent is best to design the concentration beyond the critical micelle concentration,to avoid its impact.