Study of the Shape Separation of Fine Particles Using Fluid Fields

Abstract

In order to apply hydrodynamic Gelds to the shape separation of fine particles, the dependencies of dynamic properties of particles in a cyclone on the particle shape were discussed. Glass beads, glass powders, silica sands and mica particles in a 10–100 μm size range were classified into five fractions by wet cyclones. The equivalent diameters of classified particles were measured by a free settling method, and the geometric parameters were obtained from SEM microphotos. The Stokes diameters in free settling were in agreement with the mean values which were estimated for an ellipsoid and a thin disc to settle in random orientation. On the other hand, Stokes diameters in the cyclones were smaller than those in free settling. The discrepancy between these diameters was large especially for flaky mica particles, suggesting that a cyclone can be used to separate flaky particles from bulky ones.† This report was originally printed in J. Soc. Powder Technology, Japan. 29(11), 838-844 (1992) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.