METHOD OF PRODUCTION OF LIQUID COMBINED FERTILIZERS Russian patent published in 1999 - IPC

FIELD: production of liquid combined fertilizers. SUBSTANCE: the essence of method consists in that transparent solution of liquid combined fertilizer with low content of impurities insoluble in water and absent carbon is produced by neutralization of wet-process polymetaphosphoric acid with ammonia gas. Fusion cake is dissolved to obtain cooled solution and insoluble impurities of carbon organic origin and other solid impurities are removed by filtering of solution on filter with auxiliary material layer 5-30 mm thick. Auxiliary material is used in form of waste of production of aluminum fluoride by reaction of silicofluoric acid and aluminum hydroxide (SiO₂ 78-94; AlF₃ 6-22) containing 45-60% particles sizing less than 50 mcm with porosity of 0.83-0.85. EFFECT: higher purity of solution of liquid combined fertilizers and intensified process due to exclusion of prolonged settling of suspension. 4 cl, 1 ex