METHOD OF OBTAINING LIQUID COMPLEX FERTILISERS Russian patent published in 2014 - IPC C05B7/00 

FIELD: chemistry.

SUBSTANCE: invention relates to agriculture. Method of obtaining liquid complex fertilisers includes neutralisation of extraction phosphoric acid with nitrogen-containing reagent, separation of sediment of non-soluble admixtures from obtained solution, introduction of solution of salts of microelements in presence of complex-forming agent. As nitrogen-containing reagent used is carbamide in form of water solution, taken in mole ratio carbamide: H₃PO₄, equal (1.5-2.5):1; process of neutralisation is carried out at temperature 95-99°C and density of reaction mass 1.22-1.28 g/cm³ until value of pH of reaction medium reaches 6.5-7.2 in presence of calcium-containing agent, taken in mole ratio calcium:fluorine, equal 1:2, and separation of sediment of non-soluble admixtures is carried out when pH of reaction medium reaches 5.0-5.9.

EFFECT: invention makes it possible to obtain liquid complex fertiliser with balanced composition and low content of admixtures of fluorine and sesquioxides.

2 cl, 2 tbl, 2 ex