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

FIELD: agriculture, fertilizers.

SUBSTANCE: invention relates to technology for preparing complex granulated nitrogen-phosphorus or nitrogen-phosphorus-potassium fertilizers. Method involves preparing nitrophosphate or nitrophosphate-potassium melt, addition to melt with the content of moisture 1.5%, not above, a powdered-like addition containing water-insoluble compounds of magnesium with pH value of an aqueous extract above 7.0, its mixing with melt at pH value 4.2, not less, but preferably at pH value 4.2-5.8. Dolomite, magnesite, caustic magnesite or their mixtures are used as a magnesium-containing addition. Magnesium-containing addition is mixed preliminary with potassium salt or recycled particles taken in the amount providing the content of MgO in fertilizer 0.3%, not less. Method provides preparing nitrogen-phosphorus-magnesium or nitrogen-phosphorus-potassium-magnesium fertilizers in equipment and by technological scheme used in manufacture of prillated NPK-fertilizers and using not expensive and not-deficient magnesium-containing raw with simultaneous improvement of consumers' properties of fertilizer, i. e. reducing caking and enhancing strength of fertilizer granules.

EFFECT: improved preparing method, improved and valuable properties of fertilizer.

4 cl, 5 tbl, 6 ex