Effect of particle size in swelling ratio for a bituminous coal

Swelling ratio in pyridine has been measured for a selected bituminous coal of particles sizes ranging from 10 μm to 5 mm. The density of samples after action of pyridine has been determined using a helium pycnometer. The dependences of swelling ratio and density on the size of particles have also been determined. Saturation of dependences for particles sizes of about 0.2 mm has been observed. A model explaining the dependence of swelling ratio on particle size is presented.