METHOD OF PRODUCING PHOSPHORIC ACID Russian patent published in 2009 - IPC C01B25/18 C01B25/22 C01B25/222 

FIELD: chemistry.

SUBSTANCE: invention relates to production of phosphoric acid. The method of producing phosphoric acid involves decomposition of phosphate material of sulphuric and phosphoric acid, obtaining phosphoric-acid pulp and two-step purification of phosphoric acid from impurities by introduction of settling agents, filtration of the pulp, washing phosphogypsum. At the first step of purification, impurities are precipitated by introducing phosphorite and alkaline agent into the phosphoric-acid pulp until pH of 1.8 to 2.1, where said introduction takes place after completion of decomposition of phosphate material. At the second step of purification, impurities are precipitated by neutralisation of phosphoric-acid solution with alkaline agent to pH 2.8 to 4.0.

EFFECT: method allows for obtaining phosphoric acid, pure from impurities, for production of sodium and potassium polyphosphates.

2 cl, 1 tbl, 3 ex