Abstract: A batch process for forming a granulate of predetermined granule size distribution from a powdered solid substance or, a mixture of powdered solid substances, which comprises the steps of (a) blowing hot air upwardly through a batch of said mixture of powdered substances to form a fluidized bed having a lower portion and an upper portion, (b) spraying into the upper portion of said fluidized bed a hot bonding liquid at a rate sufficient to cause the particles of the powdered substances to coalesce and initiate a buildup of granules, (c) simultaneously breaking down the built-up granules in the lower portion of the fluidized bed by impact with rigid blades moving at high speed to establish an equilibrium between build-up and break-down of granules, the granule build-up rate slightly exceeding the break-down rate, and (d) recovering the granulate when the desired granule size distribution has been achieved.