METHOD FOR PRODUCTION OF GRANULATED FERTILIZER MIXTURES Russian patent published in 2004 - IPC

FIELD: fertilizers. SUBSTANCE: granulated nitrogen-phosphorus-potassium and nitrogen-phosphorus fertilizer mixtures are produced by mixing urea with one or several mineral or mineral and organic fertilizers selected from ammonium nitrate, ammonium sulfate, ammophos, diammonium phosphate, potassium chloride and sulfate, phosphorite flour, biohum, potassium humate, and peat, content of urea in nitrogen-phosphorus-potassium mixtures ranging from 0.1 to 99.9% and weight ratio N/P₂O₅/K₂O being (15-25):(9-17):(9-17), whereas weight ratio N/P₂O₅ in nitrogen-phosphorus mixture is (11-45):(0.03-45). The two mixtures may further contain: one or several trace minerals; reinforcing additive: talk, perlite, or carbon in amount 0.1-0.3%; waterproofing additive: polymethylhydroxysiloxane emulsion (GKZh-94) in amount 0.04-0.4%. Mixtures are then moistened to water content 1.0-3.0% and granulated in standard industrial rotor granulator, after which granules are riddled. Granulated fertilizer mixtures exhibit good physicomechanical characteristics: statistic strength of granules without reinforcing additive 2.3-2.9 MPa, that with reinforcing additive 3.1-3.9 MPa, 100% friability, lack of blocking and dusting. Addition of GKZh-94 reduces hygroscopicity of granules and raises hygroscopic point by 1.0-2.4%. Yield granules with desired size 85-88%. EFFECT: improved consumer's properties. 4 cl, 5 tbl