ABSTRACT
Measurements have been made on the collapse of initially fluidized beds for a fine cohesive powder. Average particle size is 8.53 pm. For this value attractive van der Waals force exceed in several orders of magnitude the particle weight. As a result particles are agglomerated in the fluidized bed. We extend the Richardson-Zaki empirical law and Mills-Snabre theoretical law for the settling of aggregates to fit experimental data. The number of particles per aggregate N and the ratio of aggregate radius R to particle radius, a, have been chosen as fitting parameters.
