METHOD OF PREPARING NITROGEN-PHOSPHORUS COMPOUND MINERAL FERTILISER Russian patent published in 2010 - IPC C05C1/00 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing nitrogen-phosphorus compound mineral fertiliser based on ammonium nitrate with a phosphate additive. The method involves addition into a concentrated ammonium nitrate solution of a nitric acid extract of apatite, from which the calcium part is pre-separated in form of a tetrahydrate of calcium nitrate, neutralisation with ammonia, evaporation and granulation of the end product by prilling. Calcium is separated from the nitric acid extract until the ratio Ca/P₂O₅ equals 0.35-0.65. Before addition into the concentrated ammonium nitrate solution, the nitric acid extract is neutralised with ammonia and evaporated. The obtained product contains nutrient components in amount of, wt %: N - 27-33, P₂O₅ - 2-9.

EFFECT: stable operation of industrial unit AS-72.

4 cl, 2 ex