Abstract: In the process for the agglomeration of slightly soluble and hydrolytically sensitive substances, a powder of the slightly soluble substance is conducted, together with at least one water-soluble binder, in free fall through a steam atmosphere at temperatures between 85.degree. C. and 105.degree. C. essentially without the action of compacting forces. In this process, the residence time in the steam atmosphere is approximately 0.5 to 10 seconds. The agglomerates formed are then dried in free fall, so that small solid bridges form from the binder liquid bridges formed at the points of contact between the primary particles. In a following integrated fluidized-bed dryer, the final drying then takes place to a water content of less than 0.5% by weight. The process is carried out in a steam jet agglomerator in which a freely falling product curtain of the pulverulent mixture to be agglomerated is impinged by steam using steam jet nozzles (5, 6).