METHOD OF GRANULATION OF NITROGEN FERTILIZERS AND DEVICE FOR REALIZATION OF THIS METHOD Russian patent published in 2001 - IPC

FIELD: manufacture of mineral fertilizers, nitrogen fertilizers in particular; chemical and other industries. SUBSTANCE: granulation of nitrogen fertilizers is performed in fluidized bed at constant temperature below solidification temperature over entire length of granulation zone followed by cooling the recycle and directing it for repeated granulation; rarefaction of 0.0035 to 0.0045 MPa is created above fluidized bed and product thus formed is directed to classifier for separation of this product into commercial fraction of 2 to 4 mm in size, fine fraction in form of recycle, 0.5 to 2 mm in size and coarse fraction above 4 mm in size followed by crushing to sizes of recycle and partial commercial fraction followed by crushing for compensation for shortage of recycle. Device for granulation of fertilizers has housing with air supply pipe unions found in its lower and air discharge pipe unions in upper portion, common air distributing grate mounted above air supply pipe unions and granulated product discharge pipe union. Mounted inside housing is granulation unit made in form of two-roll chute with wave curved grate at angle of 45 deg. relative to level and 60 deg. at wave crest. Working grate is provided with holes in horizontal sections and in sections inclined to level at angle of 45 deg. EFFECT: increased output of target product; high quality of finished product; avoidance of local overheating due to equalization of temperature fields; low cost of process due to avoidance of powerful-gas-cleaning units. 5 cl, 5 dwg