流体場を利用した粒子の形状分離に関する基礎的検討 湿式サイクロン中における不規則形状粒子の運動特性

Abstract

In order to apply hydrodynamic fields 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 10-100μm size range were classified into five fractions by wet cylclones. 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 hands, 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 blocky ones.