Determination of trace level impurities in uranium compounds by ICP-AES after organic extraction

The determination was studied of Al, B, Be, Cd, Ca, Co, Cu, Mg, Mn, Mo, Pb, Si, Sn, V, Cr, Ni, and Fe as trace level impurities in uranium compounds by ICP-AES after extraction of uranium with three different mixtures of di-(2-ethyl-hexyl) phosphate (D2EHP) and tri-(2-ethyl-hexyl)-phosphate (T2EHP) in solvents like toluene, carbon tetrachloride, hexane and cyclohexane. The study was carried out in presence of different concentrations of HCl and HNO3. A single extraction with D2EHP in cyclohexane using nitric acid as matrix was sufficient to reduce the U3O8 concentration from 100 g/l to 100 mu g/ml. The ICP-AES instrumentation applied, allowed the determination of metal concentrations ten-times lower than those usually found in nuclear grade U3O8. To check the efficiency of the extraction and the accuracy of the proposed method, Certified Reference Materials were used in the dissolution and extraction steps. The method described can be used for the determination of trace metals in nuclear grade U3O8.