The separation of Eu and Sm from each other is made difficult by their shared preference to be a trivalent cation as well as their similar ionic radii. A new approach to separating Eu and Sm using ion exchange reactions between molten salts and a solid electrolyte, beta″-alumina, has been demonstrated. The highest separation factor achieved was greater than 30. However, the Eu extraction efficiency was low. The highest Eu extraction efficiency achieved was 51.8% ± 2.6 with a separation factor of 4.70 ± 0.46.