FIELD: air classifying of polydispersed materials; separation of fine particles by density. SUBSTANCE: material to be separated is fed in form of aeromixture over center between concentrator cover and upper outer surface of bowl- shaped rotor mounted rotatably over center of concentrator housing; concentrate is discharged spirally over inner working surface of concentrator housing; fine particles of heavy minerals and metals are re-extracted on inner riffled portion of rotor from ascending twisted vortex flow of aeromixture in form of twisted circuit downward between bowl-shaped rotor of concentrator and central exhaust tube discharging light fraction with air; concentrate from inner working surface of bowl-shaped rotor is discharged to lower circular part of concentrator where revolving boiling fluidized layer is formed by compressed air directed tangentially; then, concentrate is finally discharged to concentrate receiver through sand packings. EFFECT: enhanced efficiency. 3 cl, 2 dwg
