GRANULATED UREA PRODUCTION METHOD Russian patent published in 1999 - IPC

FIELD: production of inorganic compounds. SUBSTANCE: invention solves problems associated with removing moisture in column granulation method and concentration of dilute formaldehyde in a granulation method involving fluidized bed or fluidized spouted bed when urea is granulated in presence of formaldehyde. In method of invention, granulated urea is obtained from drops of liquid or from sprayed urea solution drops, wherein urea solution is divided into two parts (A and B) and solution of the process is obtained by combining aqueous formaldehyde solution with urea solution A, concentrating combined solution, and finally mixing it with urea solution B. Urea-to-formaldehyde molar ratio in process solution is at least 0.5, and mixing and concentration operations are carried out at pH 5 or higher. Product exhibits crushing strength 25-35 N -2.7 mm and contains 0.2 wt % moisture. EFFECT: facilitated removal of moisture. 3 cl, 1 dwg, 2 ex