METHOD FOR PRODUCING PURIFIED PHOSPHORIC ACID Russian patent published in 2023 - IPC C01B25/234 B01J20/10 B01J20/20 

FIELD: chemical industry.

SUBSTANCE: method for obtaining purified concentrated phosphoric acid from extractive phosphoric acid, which can be used in the production of technical, feed and food phosphates. The method for obtaining purified phosphoric acid includes purification of extractive phosphoric acid (EPA) with a liquid organic solvent, post-treatment with simultaneous concentration by direct contact of the acid to be purified with a gaseous heat carrier in the mode of a foam layer with stripping of fluorine compounds and circulation of the acid to be purified through it. Then, adsorption purification is carried out on a silicon oxycarbon adsorbent obtained by activation in a vibrating mill of a mixture of activated carbon and white carbon, taken in a ratio of 1:1, at an adsorbent/acid ratio of 1:(100-300). Superheated steam with a pressure of 2-3 atm and a temperature of 120-133°C is used as a heat carrier, which is condensed upon cooling to obtain fluorosilicic acid. Concentration and adsorption purification is carried out at a vacuum of 0.15-0.2 atm and a temperature of 81-86°C.

EFFECT: reducing the consumption of the adsorbent, the specific energy consumption, the emissions of fluorine-containing products into the atmosphere, and increasing the degree of purification of phosphoric acid.

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