DIAMMONIUM PHOSPHATE SYNTHESIS METHOD Russian patent published in 2010 - IPC C05B7/00 C01B25/28 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for synthesis of diammonium phosphate which has antiseptic properties. The method involves mixing phosphoric acid and spent sulphuric acid from petrochemical production in amount of 25-30 kg per ton of phosphoric acid and industrial sulphuric acid until attaining 6.5-7.0 % SO₃ content in the mixture, step by step neutralisation of ammonia with the mixture of acids until molar ratio NH₃/H₃PO₄ = 1.4, and then to 1.75, granulation, drying the product and subsequent cleaning of exhaust gases in two steps, at the first step of which ammonium phosphate pulp with molar ratio NH₃/H₃PO₄ = 0.4 -0.5 is fed, and at the second step - a mixture of acids and an additional antifoaming agent PG-3 in amount of 0.5-2 g per ton of the end product.

EFFECT: method prevents foaming of absorption solutions and enables to obtain diammonium phosphate having antiseptic properties, with high efficiency of the process.

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