Measurement of surface properties of coal using a modified washburn technique

Several physical coal cleaning processes, e.g. oil agglomeration and flotation, are dependent on the surface properties of coal. One conventional method of surface characterization involves measurement of the contact angle. The Washburn method of contact angle measurement has advantages over most other techniques used to measure the contact angle of solids in powder form. This technique involves filling a vertical cylindrical tube with the powdered solid and allowing a liquid to penetrate the powder bed by capillary driving forces. The Washburn method has been modified using fundamental equations governing fluid transport through a packed bed.