Gas-cyclones are widely used in separation or size classification
apparatus for gas–solid flows because of their simple structure and low
cost. Recently,with improvements in the dimensions of various parts of
cyclones, a fairly high level of precision in the classification of submicron
order particles has become possible[1–3]. Recent industrial
requirements of ceramics or metal powders require particle size
distributions with a narrow standard deviation, because the physical
properties of such classified particles are related to the performance of
electrical, magnetic and chemical reactions. In particular, particles with
a diameter of 0.1 to 1 μm are required for various powder handling
processes. In order to classify a particle cut size in the size range of 0.1 to
1 μm, forced centrifugal classifiers are not always effective because of
particle erosion problems and the increased maintenance costs of such
classifiers due to high revolutions