A process for the production of urea granules from a melt or solution of urea by spraying the urea melt or solution, which also contains as granulation additive formaldehyde, methylolureum, urea-formaldehyde precondensates, or hexamethylenetetramine, in the form of very fine droplets into a fluidized bed of urea particles, in which process the granulation additive is added to the melt or solution prior to the granulation at such a stage so that the mixture of the granulation additive and the urea melt or solution has a contact time of at least 20 sec., but not more than 20 min.

1997 Kayaert Hydro Agri 5653781 Process for the production of urea granules.pdf