Abstract: The present invention pertains to an improved nozzle, particularly for use in wear-resistant rotary atomizers, to atomizer wheels containing such improved nozzles and to a method for obtaining microspherical particles with a narrower particle size distribution when using such nozzles. The atomizer wheels and nozzles have at least the same wear resistance as those described in the prior art, but have been improved to provide microspherical particles with a very narrow particle size distribution. The nozzle of the present invention comprises a flow channel in the shape of a vertical slot that may be lined with wear-resistant sintered material. The vertical slot may be uniformly rounded. It was found that when these improved nozzles are used for spray-drying suspensions, microspherical particles with a narrower particle size distribution are obtained than when using nozzles with cylindrical flow channels.