FIELD: technological and geological investigations and concentration of mineral materials. SUBSTANCE: method of dry classification of powder material particles includes introduction of initial material and gas flow through holes into classifier working chamber; disintegration of initial material particles; creation of gas flow in working chamber and transfer of initial material particles into gas flow with use of rotor; conduction of classification of initial material in flow with use of stage varying of velocity of vertical gas flow due to stage successive increase of diameters of classifier vertical chambers; withdrawal of different fractions of classification from classifier chambers. For creation of gas flow in working chamber and transfer of initial material particles into chamber with use of rotor, installed in working chamber are stators; velocities of particles of gas flow are equalized in gas conduit connecting the working chamber with the first vertical chamber of classifier. Vertical gas flow is created at classifier outlet. Withdrawal of classification various fractions from classifier chambers is performed through accumulating pockets located in lower parts of classifier chambers. Conditions of classification are selected depending on initial material. EFFECT: higher quality and productivity of classification. 15 cl, 1 dwg
