Y. Koudsi et al., EFFECT OF OXIDATION-REDUCTION ON THE EXTRACTION OF URANIUM FROM WET PHOSPHORIC-ACID BY DEHPA TOPO/, Journal of radioanalytical and nuclear chemistry, 198(1), 1995, pp. 237-245
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.