METHOD OF PRODUCTION OF PHOSPHATE FERTILIZER Russian patent published in 1999 - IPC

FIELD: methods of production of fertilizers from lean phosphate raw materials with considerable content of impurities and suitable for various types of soils and for various crops. SUBSTANCE: method mixing of phosphate raw material with mineral acid and recycle, pelletizing of product and subsequent maturation and drying of product. Phosphate raw material is preliminarily moistened up to moisture content of 6-9%, mixed with mineral acid to obtain in pulp of calcium monophosphate- calcium diphosphate ratio of 1-4, added with recycle in amount required for attaining moisture content in pelletized mixture of 7-11%. Mineral acid is taken in form of, either, phosphoric, or its mixture with sulfuric acid. At stage of mixing, introduced into reaction mass are components containing microelements. EFFECT: prolonged action of produced fertilizers, provision of definite citric-soluble P₂O₅-aqueous P₂O₅ ratio, and increased strength of produced pellets. 3 cl