Structure Control of a HLW Immobilized Zirconolite Glass-Ceramic Matrix

Abstract

Resources and environment are two crucial (key) elements for the sustainable development of human society. This paper aims to explore a new glass-ceramic system for the development of high-level radioactive solid-waste vitrification technology, clarify the function of multielemental radionuclides (heterogeneous ion) on the structural and chemical durability characteristics. By changing the crystallization temperature and crystallization time, the heat treatment system of the zirconolite-based glass ceramic waste form was optimized; the K value method was used to obtain the quantitative analysis of the crystal phase; CeO2 was used as a simulated nuclide to explore the effect of CeO2 doping on the phase. The influence of composition, and the valence distribution of cerium in the glass ceramics was analyzed by XPS. The results show that the nucleation temperature is 810 °C for 2 h, and then the crystallization temperature is 950 or 1000 °C for 2 h, the glass ceramics containing only the 2M zirconolite and residual glass. CeO2 doping will lead to the increase of the lattice constant. The ratio of Ce4+ to Ce3+ in the waste form with different CeO2 content is maintained at 6:4. The normalized leaching rate of the sample with the highest doping content is 5.949 × 10−6 g·m−2·d −1.