Solvent extraction studies for recovery of uranium from thiocyanate analytical waste using DAAP

Analytical lab waste containing U in ammonium thiocyanate is generated in reprocessing laboratory. Recovery of U from such analytical waste is very important. Dialkaylalky phosphonate based extractants has high extraction efficiency over trialkyl phosphates. In the present study, the recovery of U from thiocyanate analytical waste has been examined by solvent extraction using diamylamyl phosphonate (DAAP) as extractant. DU in DAAP varies with pH and concentration of thiocyanate ligand. Uranium forms a disolvate complex with DAAP in nitric acid medium. In the present study, solvation number of U complex extracted by DAAP from thiocyanate medium was studied by mole ratio method, absorption behavior of U extracted species in DAAP and back extraction studies of U with Na₂CO₃ as strippant were carried out. These studies conclude that the U is extracted as U-SCN complex from thiocyanate waste and it forms a disolvate complex in DAAP. Extracted U is recovered by stripping with 2.25M Na₂CO₃