Investigation of the pyrometallurgical process of metallic uranium separation from rare earths oxides

Interaction between metallic uranium and rare earth oxides, i.e. neodymium oxide, were investigated using thermodynamic modeling and experimental exposures at 1300–1500 °C. It was shown that metallic uranium partly reduced neodymium oxide resulting in formation of uranium dioxide film that prevented a uniform ingot formation. Increasing temperature led to higher degree of reduction and further complicated the rare earth oxide separation from uranium metal. Direct smelting cannot be used for fissile materials extraction from a mixture of metallic and oxide components obtained during nuclear fuel reprocessing.