Stabilization/Solidification of Radioactive LiCl-KCl Waste Salt by Using SiO₂-Al₂O₃-P₂O₅(SAP) Inorganic Composite: Part 2. The Effect of SAP Composition on Stabilization/Solidification

Abstract

Metal chloride waste is generated as a main waste streams in a series of electrolytic processes of a pyrochemical process. Different from carbonate or nitrate salt, metal chloride is not decomposed into oxide and chlorine but it is just vaporized. Also, it has low compatibility with conventional silicate glasses. Our research group adapted the dechlorination approach for the immobilization of waste salt. In this study, the composition of SAP (SiO 2 -Al 2 O 3 -P 2 O 5 ) was adjusted to enhance the reactivity and to simplify the solidification process as a subsequent research. The dechlorinate the LiCl-KCl waste and its reaction product could be consolidated as a monolithic form without a glass binder. The leaching test result indicated that U-SAP 1071 was more durable than other SAPs wasteform. By using U-SAP, 1 g of waste salt could generated 3 4 g of wasteform for final disposal. The final volume would be about 3 4 times lower than the glass-bonded sodalite. From these results, it could be concluded that the dechlorination approach using U-SAP would be one of prospective methods to manage the volatile waste salt.

An experimental study on Sodalite and SAP matrices for immobilization of spent chloride salt waste

“…Glass can be added to the SAP matrix as a chemical binder giving rise to higher disposal efficiency and to a lower volume of waste compared with other immobilization matrices [27,30]. A recent evolution of SAP, the glassy wasteform U-SAP, shows even better performances with respect to other SAP wasteforms [31,32].…”