Study on Measurement and Calculation of Critical Surface Tension of Wetting Coal with Water

In order to improve the seam water injection effect, the paper introduced the coal wetting process with water.The coal surface tensions with six different aqueous solutions and the contact corner of coal samples from Chengzhuang Mine were tested and measured.The Zisman method was applied to calculate the critical s urface tension of the coal samples from Chengzhuang Mine.The results showed that the surface tension with suds would be the lowest and the average critical surface t ension of coal samples from Chengzhuang Mine would be 17.15 mN/m.As the surface tension lower than 17.15 mN/m, the water could make the coal fully wetted and fu lly expanded.Different kind water to make the surface tension higher than 17.15 mN/m, the surface tension more closely to the value and the wetting effect would be bet ter.The critical surface tension could be applied to evaluate the effect of the coal wetting with mine water.