EFFECT OF OXIDATION-REDUCTION ON THE EXTRACTION OF URANIUM FROM WET PHOSPHORIC-ACID BY DEHPA TOPO/

Uranium is recovered from wet phosphoric acid by DEHPA/TOPO in kerosen e. Uranium is present in wet phosphoric acid in the tetravalent and he xavalent states but DEHPA/TOPO extracts uranium in tile hexavalent sta te only. The ratio of U4+/U6+ depends on several factors such as the o rigin of the phosphate rock, the method of preparation of phosphoric a cid and the presence of other impurities. Therefore it is important to oxidize the wet acid to convert all uranium to U6+ before extraction. Uranium is stripped from the solvent by a reverse process where a con centrated phosphoric acid is used under reducing conditions. This pape r studies the oxidation of wet phosphoric acid from Hems plant/Syria b y H2O2 oxidant and the effect of oxidation on extraction coefficient K . It also studies the reduction by iron and its effect on back extract ion of uranium from the solvent to phosphoric acid.