Basic studies on the separation and recovery of ¹³⁷Cs from radioactive wastes using zeolite

The purpose of the studies was to find a useful procedure for the separation and recovery of ¹³⁷Cs with zeolite, a natural inorganic exchange mineral, from high level radioactive liquid wastes and reprocessing effluents. A basic study was made on representative domestic samples of zeolite to establish practical procedures for their application to radioactive treatments. Tests were performed by both batch and column methods, with various types of zeolite to determine the exchange capacity as well as the decontamination efficacy of ¹³⁷Cs from radioactive solutions. From an examination of the ion-exchange performance of domestic clay minerals, zeolite had been found to be effective in the treatment of high level radioactive wastes. Zeolite has proved extremely useful particularly for the separation and recovery of ¹³⁷Cs from highly concentrated waste containing such other elements as H⁺, Li⁺, Na⁺, Ca²⁺, Ba²⁺, Sr²⁺, Al³⁺, Fe³⁺ as well as HF. The ¹³⁷Cs fixed in the zeolite may be easily eluted with monovalent metal ions such as Na⁺, K⁺ and NH₄⁺. The ¹³⁷Cs recovered by the zeolite is ready for use as the radiation source without further treatment. Ammonium chloride is considered to be an excellent eluant, and the recovery of ¹³⁷Cs from the eluate is extremely simple. (author)