Fine coal particles are difficult to separate effectively from liquids or o
ther solids. Ultrasonic energy may be used to enhance the efficiency of the
conventional fine-particle separation processes widely used in the coal an
d mineral industries. Flotation, settling and dewatering tests were conduct
ed using several fine coal samples to study the effects of ultrasonic treat
ment on these processes. Process variables such as particle size, ultrasoni
c treatment time and solids concentration were investigated for their impac
ts on ultrasonic treatment effectiveness. The results obtained from this st
udy showed that ultrasonic treatment is an effective approach for enhancing
solid/solid separation in flotation and solid/liquid separation in sedimen
tation and dewatering of fine coal. SEM microphotographs demonstrate that u
ltrasonics cleaned particle surfaces, which is, in part, responsible for th
e observed improvement in fine coal separation processes.