Spark Plasma Sintering of Aluminosilicate Ceramic Matrices for Immobilization of Cesium Radionuclides

Abstract

The possibility of using spark plasma sintering (SPS) for preparing high-density ceramic matrices suitable for firm long-term immobilization of Cs radionuclides was examined. The kinetic features of sintering and phase formation of natural zeolite from the Far Eastern deposit, loaded with the adsorbed Cs ions (surrogate of radiocesium), under nonequilibrium SPS conditions were analyzed. The optimum SPS conditions were determined, and high-quality glass-ceramic matrices based on zeolites from various deposits, characterized by high density (98.5–99.8% of theoretical density), high compression strength (470–490 MPa), Cs content of up to 20.8 wt%, and low Cs leach rates (<10⁻⁵–10⁻⁶ g cm⁻² day⁻¹), were prepared. The SPS technology shows promise for radioactive waste management (in particular, for solidification of spent radioactive sorbents) and radioisotope industry (in particular, for production of special-purpose radionuclide sources).