Method for the treatment of solid particles for the purpose of agglomeration, coating, layering, spray granulation or pelletisation in a fluidisation apparatus, in which the solid particles are sprayed with the setting of a specific dwell time spectrum, wherein the fluidisation apparatus has a rotary dryer star which is installed in the fluidisation apparatus to segment a swirl chamber into process chambers, wherein the swirl chamber mounted above a distribution chamber consists of an outer casing, which has a solid particle inlet unit and a solid particle outlet unit, - wherein the rotary dryer star is rotatably mounted and has partition walls for conveyance of the solid particles along a conveyor line, and below the rotary dryer star is provided a diffuser plate, rotatable with and releasable from the former, and wherein the partition walls extend over the entire height of the swirl chamber; the method comprises: - continuous feeding of solid particles via the solid particle inlet unit, - introduction of a fluid through nozzles for the treatment of the introduced solid particles in the process chambers, in which the solid particles are conveyed through the swirl chamber with an exactly defined dwell time, and wherein the dwell time of the solid particles is defined directly via the speed of the rotary dryer star, - so that the dwell time spectrum is set as the ratio between the dwell time of the solid particles with 10% cumulative distribution t RTD.10 and the dwell time of the solid particles with 90% cumulative distribution t RTD.90 in the fluidisation apparatus with t RTD.10 / t RTD.90 ≤ 3. - wherein the rotary dryer star is rotatably mounted and has partition walls for conveyance of the solid particles along a conveyor line, and below the rotary dryer star is provided a diffuser plate, rotatable with and releasable from the former, and wherein the partition walls extend over the entire height of the swirl chamber; the method comprises: - continuous feeding of solid particles via the solid particle inlet unit, - introduction of a fluid through nozzles for the treatment of the introduced solid particles in the process chambers, in which the solid particles are conveyed through the swirl chamber with an exactly defined dwell time, and wherein the dwell time of the solid particles is defined directly via the speed of the rotary dryer star, - so that the dwell time spectrum is set as the ratio between the dwell time of the solid particles with 10% cumulative distribution t RTD.10 and the dwell time of the solid particles with 90% cumulative distribution t RTD.90 in the fluidisation apparatus with t RTD.10 / t RTD.90 ≤ 3. - continuous feeding of solid particles via the solid particle inlet unit, - introduction of a fluid through nozzles for the treatment of the introduced solid particles in the process chambers, in which the solid particles are conveyed through the swirl chamber with an exactly defined dwell time, and wherein the dwell time of the solid particles is defined directly via the speed of the rotary dryer star, - so that the dwell time spectrum is set as the ratio between the dwell time of the solid particles with 10% cumulative distribution t RTD.10 and the dwell time of the solid particles with 90% cumulative distribution t RTD.90 in the fluidisation apparatus with t RTD.10 / t RTD.90 ≤ 3.