A Modified Suction Potential Method for Measuring the Three-Phase Contact Angle

Abstract

The suction potential method for measuring the three-phase contact angle was modified and used to determine the oil-water-solid contact angle for various samples of coal. The method involves measuring the pressure changes required to draw an oil/water interface and then an oil/air interface into a packed bed of solid particles. Before the latest modification, the method was very time consuming and difficult to control. These problems were overcome by modifying the apparatus and measuring technique. Values of the contact angle determined with the new technique were very similar and as reproducible as those determined with the older method. Also, measurements of the contact angle for a series of oxidized coal samples were consistent with other surface property measurements. In addition, for this series of samples, the recovery of coal from an aqueous suspension by oil agglomeration was found to correlate very well with the contact angle.

Keywords:

• Coal surface
• Wettability
• Contact angle
• Oil agglomeration
• Heat of immersion
• Hydrophilicity index