CONSTANT-PRESSURE FILTRATION OF SUBMICRON PARTICLES

The mechanism of cake formation in constant pressure filtrations of su bmicron particles is studied by analysing the forces exerted on the de positing particles. The Brownian dynamic method is used to trace the l oci of slurry particles and to simulate the packing structure of submi cron particles in filtrations. The major factors affecting the particl e packing, such as frictional drag, van der Waals' force, electrostati c force, and Brownian force, etc., are discussed. The most compact cak e is found when the frictional drag and Brownian force are of the same order of magnitude. A numerical program is designed to estimate the v ariations of local cake properties during a course of constant pressur e filtration. The calculated results of average cake porosity and aver age specific filtration resistance agree very well with the experiment al data.