Contact Angle Measurements on Discs Compressed From Fine Coal

Abstract

The contact angle of water on fine coal particles was measured on a flat surface formed by pressing the coal powder into a highly compacted disc. A model that considers solid particles and pores as major disc consituents was employed. The fractional area of pores on the disc surface was postulated being equal to the disc bulk porosity under the assumption of uniform porosity within the disc and of negligible plastic deformation and crushing action on the particles on the disc surface. The predominant effect of disc porosity on the contact angle was corrected using the Cassie-Baxler equation.

The proposed correction procedure for the apparent contact angle values directly measured was also evaluated by using the model to calculate the contact angle of water on coal organic matter. The reasonable values, which were obtained, seem to confirm the procedure. The correcting procedure was also utilized to analyze the data available in literature.

Keywords:

• Coal surface
• Coal wettability
• Contact angle
• Fine coal wettability
• Compressed disc
• wettability
• Cassie-Baxter equation

Additional information

Notes on contributors

J. S. LASKOWSKI

To whom all the correspondence should be directed