METHOD FOR TREATMENT OF WET-PROCESS PHOSPHORIC ACID Russian patent published in 2007 - IPC C01B25/234 C01B25/46 

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for treatment of wet-process phosphorus acid from impurities. Method for treatment of wet-process phosphoric acid involves step-by-step extraction of phosphoric acid with tributyl phosphate, aqueous re-extraction of phosphoric acid from organic phase carried out in pulsation regimen, separation of aqueous and organic phases after extraction and re-extraction steps and recovery of regenerated extractant to extraction step. Step-by-step extraction is carried out for two stages. At the first stage the parent wet-process phosphoric acid and extractant containing 5-12% of phosphoric acid from the second extraction stage are fed. Process in the first stage is carried out up to extraction of 0.5-0.75 mas. p. p. of H₃PO₄ from the parent acid to extract that is fed to re-extraction, and raffinate obtained in this stage is fed to the second extraction stage that is carried out in the presence of sulfuric acid and in the ratio H₃PO₄ : H₂SO₄ = (1.5-10.5):1. Invention provides enhancing yield of purified acid.

EFFECT: improved method of treatment.

3 cl, 1 tbl, 6 ex