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

FIELD: agriculture, fertilizers. SUBSTANCE: invention relates to technology for manufacturing complex water-soluble nitrogen-phosphorus fertilizers used in agriculture for soils of different species. As a phosphorus-containing component the method involves using nitrate-ammonium-phosphate solution prepared by neutralization of nitric acid extract formed as result of decomposition of apatite with nitric acid and the following separation of calcium nitrate. Then this solution is diluted with water or condensate up to the salt concentration 55-65% is mixed with the conversion ammonium nitrate solution in the concentration 55-92% up to the ratio N : P₂O_{5woter-soluble}, = (2.3-11.3): 1. Method involves purification of nitrate-ammonium- -phosphate solution or its mixture with conversion ammonium nitrate from water-insoluble impurities. Prepared fertilizers show good physical-chemical indices, they contain water-soluble phosphates only wherein amount of water-insoluble compounds do not exceed 0.2%. The total content of nutrient substances in prepared fertilizers is 36%, not less, in the ratio N : P₂O_{5woter-soluble} = (2.3-11.3):1. EFFECT: improved preparing method of fertilizers. 4 cl, 1 tbl, 2 dwg