| Abstract Scope |
Innovative materials and processes are required to manage molten salt wastes from chemical processing of used fuels and molten salt reactors with complex waste streams ranging from halides, alkalis, alkaline earths, lanthanide and actinides. Common features of halides, alkalis and alkaline earths are relatively high volatility and thus it is very challenging to incorporate them into borosilicate glass due to their limited solubility and incompatibility with the high temperature vitrification process. Metal halide perovskite (MHP) structures show great potential as waste form materials for immobilizing alkaline halides generated from molten salt reactor’s waste streams. Achieving high waste loading, low-temperature synthesis, and high reaction yield is crucial for practical implementation. In this study, we explored a novel low-temperature wet chemistry process to optimize the synthesis and high reaction yield of MHP-based waste forms. Systematic experiments were performed to immobilize NaF into Na₂SnF₆ at room temperature using an organic solvent. The influence of NaF grain size, reaction temperature, and the addition of a surfactant on the reaction efficiency and product yield was thoroughly investigated. Moreover, KF, NaF, and their mixture (FNaK) were also immobilized at room temperature in DI water into MHP’s with the general formula A+2/3BF6, where A is Na and K and B is Si and Fe. The obtained results imply that the simple and low temperature wet chemistry process is cost-effective for synthesizing MHPs as potential waste form materials for effective management of salt waste. |