Abstract: An apparatus used for coating particles has a vessel in which a rotor which can be rotated about a vertical axis and possesses a disk. During coating of particles, the particles rest on the disk and are moved by the latter as a result of rotation, a process gas also being passed upward through an annular gap present between the wall of the vessel and the disk. The apparatus has at least one atomizing member which projects into the particle bed present on the disk. A coating material which is solid at room temperature is melted at least for the major part, sprayed by means of the atomizing member in the interior of the particle bed and onto the particles, and solidified by cooling. Pore-free and smooth coatings can be applied in this manner.

Abstract: An apparatus for layering powder onto particles has a vessel in which a rotor is mounted rotatable therein around a vertical axis. The rotor is a disc with a supporting surface for supporting particles. The apparatus also has a feeder with a substantially horizontal introducing member protruding slightly into the vessel above the disc. The introducing member limits a liquid outlet and an annular powder outlet encompassing the liquid outlet. During a layering operation, the introducing member protrudes into a bed of particles lying on the rotating disc and moved by the latter. There can then be sprayed liquid and powder simultaneously onto the particles passing in proximity of the outlets. This enables layering powder onto particles to produce thereby pellets having sizes lying in a narrow range.