| abstract |
CRYSTALLINE UREA HAVING A LOW BIURET CONTENT AND A LOW BULK DENSITY IS PREPARED BY INTRODUCING A CONCENTRATED, AQUEOUS SOLUTION OF UREA TO A CRYSTALLIZATION ZONE UNDER CONDITIONS EFFECTING EVAPORATION OF SOME OF THE WATER FROM THE SOLUTION AND FORMATION OF UREA CRYSTALS ON THE SOLUTION SURFACE. THE CRYSTALS ARE SKIMMED FROM THE SOLUTION SURFACE ONTO A UREA-ADHERING SURFACE, FOR EXAMPLE, ONTO A ROTATING DRUM. |