METHOD OF PURIFYING EXTRACTION PHOSPHORIC ACID Russian patent published in 2025 - IPC C01B25/234 C01B25/46 B01D11/04 B01J20/10 B01J20/20 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry. Method of producing purified concentrated phosphoric acid from extraction phosphoric acid involves purifying extraction phosphoric acid with a liquid organic solvent. Additional purification with simultaneous concentration is carried out by direct contact of the acid to be purified with a gaseous heat carrier in the mode of a foam layer with stripping of fluoride compounds and circulation of the acid to be purified through it. Adsorption purification is carried out at 100 °C on a silicon-oxycarbon adsorbent with an adsorbent/acid ratio of 1:100. Superheated steam is used as heat carrier. Concentration and purification is carried out at rarefaction of 0.15 ata and at temperature of 80 °C. Silicon-oxycarbon adsorbent is prepared by mechanical treatment of a mixture of activated carbon (AC), pre-washed with 3% hydrochloric acid solution, dried at 100 °C for 24 hours, and white soot (WS) with ratio of these components AC:WS 1:(0.25-2).

EFFECT: invention reduces consumption of adsorbent, increases degree of purification of phosphoric acid, reduces emissions of fluorine-containing products into atmosphere.

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