Uranium stripping from tertiary amine by sulfuric acid solution and its precipitation as uranium peroxide

Abstract The uranium stripping results from a loaded tertiary amine (Alamine ® 336) by sulfuric acid solution and the uranium peroxide precipitation from the pregnant strip solution (PSS) are presented. The following steps were investigated: (i) uranium stripping; (ii) sulfate content reduction from the PSS and (iii) uranium peroxide precipitation. The experiments were carried out in batch as well as in continuous scale. In the stripping stage, a PSS containing 96 g/L of U 3 O 8 was obtained, using a 4.0 mol/L H 2 SO 4 stripping solution in six mixer-settler stages. The sulfate content reduction from the PSS was carried out by the addition of lime up to pH 3.0. After sulfate excess removal, uranium precipitation was carried out by H 2 O 2 and MgO/Mg(OH) 2 powder addition. A calcining product assaying 99.7% U 3 O 8 was obtained.