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 1 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 1.75, granulation, drying the product and subsequent cleaning of exhaust gases in two steps, at the first step of which an ammonium phosphate pulp with molar ratio NH₃/H₃PO₄ = 0.4-0.5 is fed, and at the second step - the mixture of acids and an additional antifoaming agent PG-3 in amount of 0.5-2 g per 1 ton of the end product.

EFFECT: method prevents foaming of absorption solutions and enables obtaining diammonium phosphate with antiseptic properties with high output of the process, as well as use of spent sulphuric acid from petrochemical production wastes.

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