Process for segregating powdered materials into fractions of different particle size

Claim 1

PROCESS FOR SEGREGATING POWDERED MATERIAL CONTAINING FINE PARTICLES HAVING DIAMETERS LESS THAN ABOUT 10$ AND COARSER PARTICLES INTO FRACTIONS WHEREIN FINER AND COARSER PARTICLES, RESPECTIVELY, ARE CONCENTRATED, COMPRISING THE STEPS OF SUBJECTING THE SAID MATERIAL TO A SOLEY MECHANICAL TREATMENT FOR CAUSING THE FINER PARTICLES TO CONGLOMERATE BY PASSING A GAS THROUGH A LAYER OF SAID MATERIAL UPWARDS AT A VELOCITY TO BRING SAID PARTICLES TO A FLUIDIZED STATE, MAINTAINING THE PARTICLES IN THE SAID FLUIDIZED STATE UNTIL FINER PARTICLES HAVE FOMED CONGLOMERATES LARGER THAN THE COARSER PARTICLES, AND PHYSCIALLY SEPARATING THE RESULTING CONGLOMERATES FO FINER PARTICLES FROM THE UNCONGLOMERATED, COARSER PARTICLES BY SUBJECTING THE RESULTING MATERIAL TO A SEPARATORY TREATMENT WHICH EFFECTS A SEPARATION ON THE BASIS OF PARTICLE SIZES.