Abstract: An apparatus and process for classifying fine particles from a particulate material, such as toner and pigment powders. The apparatus is generally a dynamic centrifugal gas (air) classifier that combines the operational advantages of centrifugal air classifiers with increased aerodynamic forces provided by a rotating member to classify powders at cutpoints of fifteen micrometers and finer. The classifier is configured to have an annular-shaped inner passage, an annular-shaped outer passage circumscribing the inner passage, and an inlet through which a gas-entrained particulate material is introduced substantially tangentially into the inner passage so as to impart a centrifugal force to the particulate material. A portion of the entraining gas is preferably separated and directed into the outer passage.