METHOD FOR PREPARING COMPLEX FERTILIZERS Russian patent published in 2004 - IPC

FIELD: chemical technology, fertilizers. SUBSTANCE: invention relates to a method for preparing complex NPK-fertilizers widely used in agriculture. Method involves neutralization of a mixture of phosphoric and sulfuric acid with ammonium to obtain phosphate pulp, addition of potassium-containing component, granulation and drying the product. As phosphoric acid method involves using non-evaporated phosphoric acid. Sulfuric acid is added in the amount 0.2-0.5 t per 1 t of P₂O₅ and ammonium for neutralization stage is fed in the amount that is necessary to get the mole ratio NH₃ : H₃PO₄ = 1.0-1.5. The prepared phosphate pulp is mixed with potassium-containing component and then the mixing product is fed to granulation and drying. The granulation and drying processes are carried out simultaneously. Potassium chloride or potassium sulfate is used as a potassium-containing component. Method provides reducing energy consumptions, to enhance quality of complex fertilizers, to reduce mixing capacity of fertilizers and to enhance the yield of the commercial fraction. EFFECT: improved preparing method. 2 cl, 5 ex