Separation of palladium from simulated high-level liquid waste by hybrid microcapsules

Onishi, Takashi  ; Koyama, Shinichi  ; Mimura, Hitoshi*

Fission products are generated by fission reaction in a nuclear fuel. Platinum group elements, such as ruthenium (Ru), rhodium (Rh) and palladium (Rh) are also produced. Their elements play important roles in chemical and electrical industry. Mimura et al. developed hybrid microcapsules for recovery of these useful platinum group elements from high-level liquid waste (HLLWs). The hybrid microcapsules enclosing KCuFC (potassium copper hexacyanoferrate) immobilized by alginate gel were prepared. The hybrid microcapsules adsorbed Ru, Rh and Pd in single element solutions. Recovery experiments from simulated high level radioactive liquid waste were conducted in this study. Most of the Ru, Rh and Pd were adsorbed together on the hybrid microcapsules from the simulated HLLWs. A conversion method of Pd solid from solution was also proposed for effective use of recovered palladium. The separated Pd solution was converted to solid materials by thermal decomposition and acid digestion.