A device for the selective granulometric separation of solid powdery materials using centrifugal action, capable of separating materials into a fine material fraction and a coarse material fraction, includes: a housing, a cylindrical rotor rotatable, relative to the housing, about a vertical axis inside the housing and provided with blades evenly distributed on the periphery of an upper outlet opening through which a stream of gas, laden with particles having a size lower than a predetermined particle size, is drawn, a set of vertical adjustable vanes evenly distributed about the rotor along the generatrices of a virtual cylinder and directing the gas stream towards the rotor, elements for feeding the particles between the vanes and the rotor, collecting unit lower than the rotor for collecting the unfed particles having fallen and having a size larger than the predetermined particle size. The collecting unit includes a peripheral system with a fluidized bed extending about the rotor axis, at least underneath the vanes and the gap between the vanes and the rotor.