COMPLEX NITROGEN PHOSPHORIC MINERAL FERTILIZER AND METHOD OF PREPARING THEREOF Russian patent published in 2001 - IPC

FIELD: agriculture, more particularly application in any soils. SUBSTANCE: fertilizer comprises nutrient substances, wt %: nitrogen, 33 1; phosphorus pentoxide, 2-6 ammonium nitrate, 92.5 3; monoammonum phosphate,6.5 3.2; and ammonium sulfate, 0.02-2.0. Fertilizer is prepared by stepwise neutralization with addition of phosphoric and sulfuric acids, evaporation of neutralized solution and granulation of desired product. Use is made of phosphoric acid resulting from sulfuric acid decomposition of natural calcium phosphate and which is added in amount of 20-60 Kg calculated for P₂O₅ per 1 t of desired product into reactor above ammonia-nitric acid mixing zone, and neutralization in first stage is carried out to residual acidity of 8-40 g/l calculated for nitric acid. EFFECT: higher content of phosphorus in water - soluble form in fertilizer and use of readily available stock, namely extraction phosphoric acid. 3 cl, 1 ex