METHOD PRODUCING FERTILISER CONTAINING NITROGEN, PHOSPHORUS AND SULPHUR Russian patent published in 2011 - IPC C05G1/06 

FIELD: chemistry.

SUBSTANCE: invention relates to production of compound fertiliser containing nitrogen, phosphorus and sulphur and used in agriculture, for example during production of ammonium-phosphate-sulphate. The method involves neutralisation of a mixture of phosphoric acid and sulphuric acid with ammonia in three steps. At the first step, absorption liquid from purification of exhaust gases from container-type reactor 1, granulator 3 and drying drum 4 is mixed with wet-process phosphoric acid to obtain a mixture with density of 1.35 - 1.45 t/m³ and then neutralised in reactor 1 to obtain a reaction mass with molar ratio NH₃/H₃PO₄ equal to 0.2-0.5. At the second step, the obtained reaction mass and sulphuric acid are neutralised in a tubular reactor 2 until achieving molar ratio NH₃/H₃PO₄ equal to 0.8-0.9 with separate inlet of acids. At the third step, the pulp undergoes further neutralisation in an ammoniator - granulator 3 to the required molar ratio of NH₃/H₃PO₄. The end product undergoes granulation and drying. Phosphoric acid is taken in concentration of 32-40% P₂O₅.

EFFECT: invention enables to obtain a wide range of nitrogen-phosphorus fertiliser with different combinations of nutrient substances: nitrogen in ammonia form, phosphorus and sulphur with high reliability of the processing equipment and high output of the equipment.

2 cl, 1 dwg, 1 tbl, 6 ex