METHOD OF PHOSPHORIC FERTILISER PRODUCTION Russian patent published in 2009 - IPC C05B11/12 C01B25/445 

FIELD: agriculture.

SUBSTANCE: potassium chloride is decomposed by wet-process phosphoric acid taken in the amount of 90-110% of stoichiometry under the temperature of 75-90°C; the obtained pulp is thermally treated under the temperature of 320-380°C until potassium metaphosphate is produced and the hydrogen chloride which is isolated during the decomposition and thermal treatment is recovered by water producing 17-20% waste acid which is then supplied for the decomposition of poor phosphate raw material and the decomposition is carried out under the acid rate of 60-70% (in terms of CaO) of stoichiometry and the temperature of 50-90°C; the obtained pulp is granulated and dried by known methods. Potassium chloride with the proportion of P₂O₅:K₂O = 1:(1-1.5) is added at the granulation phase to produce phosphoric-potassium fertiliser.

EFFECT: method allows for the production of phosphoric fertilizers with different P₂O₅ content and different proportions of water-soluble and assimilable forms using cheap raw materials and for the elimination of the disadvantages of the known methods for decomposing poor phosphate raw material by hydrochloric acid.

2 cl, 4 ex