METHOD FOR PREPARING MONOAMMONIUM PHOSPHATE Russian patent published in 2005 - IPC

FIELD: fertilizers, chemical technology.

SUBSTANCE: invention relates to a method for preparing monoammonium phosphate used broadly as a mineral fertilizer. Method involves decomposition of phosphate with a mixture of phosphoric and sulfuric acid, separation of reaction mass with isolation of the production acid, its purifying from impurities, concentrating, ammoniation to obtain phosphate pulp and the following procedures of granulation and drying. The separated production acid is concentrated and then subjected for purification from impurities and ammoniated maintaining the content of P₂O₅ in the concentrated acid at these stages in the range 52-56%, the content of SO₃ at the range 1.5-3.2%, the residual content of solid impurities in the cleared concentrated acid 0.2-0.6% by mass, and the mole ratio NH₃ : H₃PO₄ in the range 1.01-1.16. Regulation of the yield for required sort of monoammonium phosphate by the content of main nutrient substances and the ratio is carried out by change of the SO₃ content in dilute phosphoric acid and by change of the mole ratio NH₃ : H₃PO₄ in the ammoniation process. Invention provides enhancing content of total sum of nutrient substances in the fertilizer and enhancing strength index of granules and their homogeneity.

EFFECT: improved preparing method.

2 cl, 4 ex