METHOD OF PURIFICATION OF EXTRACTION PHOSPHORIC ACID Russian patent published in 2003 - IPC

FIELD: methods of production of phosphoric acid at low content of admixtures for production of food, fodder and technical phosphates and complex fertilizers. SUBSTANCE: proposed method includes stepped extraction of phosphoric acid by organic solvent tributylphosphate followed by separation of aqueous and organic phases at obtaining extract and re-extraction of phosphoric acid for forming emulsion under action of air in pulsating mode; magnesium or strontium compounds are introduced into starting extraction phosphoric acid in the amount ensuring mole ratio of Mg/SO₄ or Sr/SO₄ equal to (1.1-10):1; extraction is performed at volume ratio of organic and aqueous phases equal to (2.5- 8):1; intensity of pulsation at extraction is maintained within 100-900 mm/min; washing of extract with water or phosphoric acid solution is performed at volume ratio of organic and aqueous phases equal to (5- 25):1; process is continued till mass fraction of P₂O₅ in washed extract reaches 7.3 to 15.5%. Proposed method stabilizes quality of productive acid at increased yield with no change in degree of extraction of P₂O₅ from acid. EFFECT: enhanced efficiency. 4 cl, 1 tbl, 2 ex