Separation of thorium from radioactive liquid waste by OXAL process

Abstract

The OXAL process has been used for the removal of thorium by carrier precipitation with cerium oxalate in acidic medium. This process may also be used for the combined separation of actinide and lanthanide fractions of radioactive liquid waste, as only these oxalates can be precipitated in this medium. Effects of important parameters e.g., precipitant dose, effluent <em>p</em>H and presence of a completing agent like EDTA, are reported. Thus, at <em>p</em>H , a larger than the stoichiometric amount of oxalate (about 2.5 times) with respect to Ce, is required to provide high removal of thorium, while any amount of EDTA interferes with the system. Electrophoretic studies have been carried out for characterizing the precipitate, with respect to phase separation.