Application of Electroreduction of Europium in the Production of Gadolinium-153

摘要

The Oak Ridge National Laboratory (ORNL) is presently producing sup 153 Gd by the neutron irradiation of normal europium in the form of Eu sub 2 O sub 3 . The resulting europium-to-gadolinium weight ratio produced after a one-cycle (approximately 21 days) irradiation of normal europium in the High Flux Isotope Reactor (HFIR) approaches 17. To achieve the required greater than or equal to99.99% radiochemical purity of the sup 153 Gd product and to achieve a respectable yield, the gadolinium must be quantitatively separated from the europium. This is achieved in a two-step process. First, the bulk (90 to 95%) of the europium is removed by the selective electroreduction of Eu(III) to Eu(II) using zinc electrodes in an electrolytic cell that contains H sub 2 SO sub 4 . Efficient europium removal is achieved in 4 h at a current density of 14.9 mA/cm sup 2 . The remaining europium is separated from the gadolinium in a second step that involves the use of high-pressure ion exchange. The introduction of the electrolytic step in the sup 153 Gd production process increased the process capacity by a factor of four and increased the sup 153 Gd yield by greater than or equal to 70%. 7 refs., 6 figs., 1 tab. (ERA citation 12:020805)