PURPOSE: To form dense and homogeneous spherical particles by providing internally a rotary disc having a truncated circular cone shape in a fluidization chamber of a fluidized granulator and inducing cyclonic flow in fluidized layers.

CONSTITUTION: The diameter of a fluidized chamber 1 at the part of height of 1/4W1/2 of the overall height from the bottom 8 surface is made larger than the diameters of the bottom 8 and the top part. A rotary disc 4 having a truncated circular cone shape is provided to a revolving shaft 15 erected at the centerline of the bottom 8. A prescribed amt. of powder and granules are charged into the chamber 1 and while hot air is fed from the bottom 8, the disc 4 is rotated and a binder soln. is sprayed from nozzles 17. A cyclonic flow is thus induced in the hot air and the powder and granules ascend while swirling and are acted by centrifugal forces by which the powder and granules are brought into impulsive contact with the inside wall surface of the chamber 1 and the inside and outside lateral surfaces of the disc 4 and are thus ground to dense spherical bodies. The disc 4 is rotated in a 200W1,000rpm range to maintain the impulsive contact power on the powder and granules to be constant.