Rotary dryer star and method for treating solid particles

A method for the treatment of solid particles for the purpose of agglomeration, coating, layering, spray granulation or pelletizing in a fluid-bed apparatus in which the solid particles are spray-coated with a specific retention time spectrum being set, comprising

• (a) providing a star-shaped rotation dryer for segmenting a fluidizing chamber into process compartments, wherein the star-shaped rotation dryer is pivot-mounted and comprises a central conical shaft and dividing walls connecting to and protruding from the central conical shaft for the conveyance of solid particles along a conveyance path;
• (b) detachably mounting a flow-receiving base to the central conical shaft below the star-shaped rotation dryer in a manner such that the flow-receiving base rotates with the star-shaped rotation dryer, the flow-receiving base comprising a central conical shaft receiving portion, the central conical shaft receiving portion being shape fit to the central conical shaft;
• (c) spray-coating the solid particles in the star-shaped rotation dryer;
• and
• (d) conveying the solid particles along the conveyance path;
• wherein the retention time spectrum as a ratio of the solid particles retention time in the fluid-bed apparatus with a 10% cumulative distribution and a 90% cumulative distribution has a margin of at least 1:3.