Structure and Performance Sensitivity to Simulated An4+ Waste Doping in a High-Silicon Glasses-Ceramics

Inspired by the long-term stability of natural radioactive rocks, a kind of high-silicon granite has been proposed as a potential aluminosilicate glass-ceramics matrix for actinide waste disposal. With the characteristic of secondary diagenesis, the loading capacity of the natural granite to simulated waste (CeO2) is 8 wt.%, reached through doping induced O/Si ratio increase. By adjusting the critical Al/Si ratio in the matrix, the loading capacity increases to 20 wt.%. Both the reductive Fe3O4 and thermal defects in CeO2 cause the valence change of Ce in the reaction. As a charge compensator, most Ce ions were hidden in a shelf-like aluminosilicate glass network, while part of reduced Ce ions exists in Ce2Si2O7 ceramic.