Vibro-fluidization of fine boron nitride powder at low pressure

At low pressure (less than atmospheric), a vibro-fluidized bed was construc ted for the fluidization of fine BN powder. This powder exhibits the charac teristics of a Geldart C type powder, with significant cohesive behavior. F ine BN particles form lightly bonded agglomerates that remain in the bed du ring fluidization. The agglomerate size was measured in situ during fluidiz ation using a pulsed laser coupled with a CCD camera. An increase in the vi brational force causes a corresponding decrease in the size of the agglomer ates. Vacuum level does not affect agglomerate size. A balance of forces mo del is used to derive an equation that predicts the minimum fluidization ve locity (u(mf)), taking into account the forces due to vibration, cohesion, gravity and drag. (C) 2001 Elsevier Science B.V. All rights reserved.