METHOD OF PREPARING COMPLEX FERTILIZERS Russian patent published in 1998 - IPC

FIELD: chemical industry. SUBSTANCE: claimed method comprises mixing phosphoric and sulfuric acids with ammonia, granulating and drying the product. Ammonia and phosphoric acid are mixed to P₂O₅:N = 1:(2,2-20) molar ratio of 1:(2.2-20) and subsequently adding sulfuric acid and P₂O₅:N molar ratio is maintained at 4:5 -20 and at 90-150 C. Potassium containing additive may also be used to P₂O₅:K₂O molar ratio of 1:(0.5-10). Potassium containing additive includes potassium chloride, potassium sulfate, potassium-magnesia and is added either to suspension or to granulation stage. The claimed method makes it possible to avoid using production equipment made of special corrosion resistant steels. EFFECT: wider range of fertilizers. 3 cl