METHOD FOR PRODUCING PURIFIED EXTRACTION PHOSPHORIC ACID Russian patent published in 2023 - IPC C01B25/234 C01B25/235 C01B25/46 

FIELD: chemical industry.

SUBSTANCE: method for producing purified extraction phosphoric acid, used as a raw material for the production of mineral fertilizers, as a food additive included in confectionery products, carbonated drinks, syrups, sausages, processed cheeses, and also used in cosmetics, dentistry and other areas. The method includes receiving extraction phosphoric acid, precipitation of gypsum and clarification of phosphoric acid by adding chalk, a solution of sodium polysulfide and evaporated phosphoric acid with further filtration. The phosphoric acid is cooled and filtered, the evaporated phosphoric acid is extracted with a tributyl phosphate solvent, fluoride and organic impurities are steam distilled, the phosphoric acid is evaporated to at least 75% by weight of H₃PO₄ and carbon purification is carried out.

EFFECT: providing a method for producing purified phosphoric acid using a combined purification method with a P₂O₅ content of at least 53% from weak phosphoric acid with a P₂O₅ content of 18-22%.

1 cl, 2 ex