Abstract: Uranium in wet-process phosphoric acid in the tetravalent state is extracted with an alkylphenyl acid phosphate extractant comprising a mixture of mono- and di(alkylphenyl) esters of orthophosphoric acid. The pregnant extractant is stripped with a suitable stripping solution, and the barren extractant recycled to the extractant step. At least a portion of the recycled extractant is treated with concentrated sulphuric acid to remove organic and inorganic impurities including alkylphenol present in the barren extractant as a result of hydrolysis from the mixture of mono- and di-(alkylphenyl) esters of orthophosphoric acid to regenerate the extractant.

Abstract: Uranium in wet-process phosphoric acid in the tetravalent state is extracted with an alkylphenyl acid phosphate extractant. The uranium in the pregnant extractant is then oxidized to the hexavalent state and stripped with a phosphoric acid stripping solution. Hydrolysis of the extractant is decreased by decreasing the proton concentration of the extractant which results from acidic impurities, e.g., sulfuric acid and fluorosilicic acid, originally present in the wet-process phosphoric acid. The proton concentration of the extractant is reduced indirectly by treating the phosphoric acid strip solution (1) with reagents which react with the acidic impurities to form water and an insoluble precipitate which is removed from the stripping solution; (2) with reagents to neutralize the acidic impurities in the stripping solution; or (3) by passing the stripping solution through a suitable ion exchange column.