Zhangyi Huang,Qiuyao Li,Yutong Zhang,Junjing Duan,Haomin Wang,Zhe Tang,Yao Yang,Jianqi Qi,Tiecheng Lu
A nitrate–citrate combustion method combined with microwave sintering was firstly employed for the rapid fabrication of the Gd 2 Zr 2 O 7 matrix immobilizing various amounts of simulated nuclear wastes . Phase evolutions, microstructure changes, element distributions, densification processes and mechanical properties of the as-prepared (1 – x )Gd 2 Zr 2 O 7 · x TRPO (0.0 ≤ x ≤ 0.6) at various temperatures were investigated. Compared to the reported studies, we have increased the immobilization amount of simulated TRPO waste within a crystal structure from 45 to 60 wt%. T d and T g (the threshold temperatures to trigger accelerated densification and grain growth, respectively) were employed to divide the densification process into three stages. the mechanical properties and the densification stages of the (1 – x )Gd 2 Zr 2 O 7 · x TRPO (0.0 ≤ x ≤ 0.6) ceramics sintered under microwave sintering at various temperatures were finally determined. Fine-grained (1 – x )Gd 2 Zr 2 O 7 · x TRPO (0.0 ≤ x ≤ 0.6) ceramic waste forms with average grain size less than 200 nm and relative density higher than 90% can be obtained by microwave sintering at sintering temperature less than 1400 °C.
Long Fan,Xiaoyan Shu,Xirui Lu,Yi Xie,Yi Ding,Tao Duan,Bingrong Dang,Yanlin Wu
The present work explores the potential of Gd 2 Zr 2 O 7 pyrochlore based materials for incorporation of trialkyl phosphine oxides (TRPO) waste which is a mixture of multi-nuclides with multi-valence. A series of (Gd,A) 2 (Zr,B) 2 O 7 ceramics were synthesized to investigate the influence of multi-nuclides incorporation on phase structure and aqueous stability of Gd 2 Zr 2 O 7 . XRD and BSE results show that all the ceramics exhibit a single pyrochlore structure. Raman spectroscopy reveals that the degree of structural order for (Gd,A) 2 (Zr,B) 2 O 7 solid solutions increases with enhanced TRPO waste content. In addition, aqueous stability testing was carried out using the MCC-1 static leach test method. The results demonstrate that the normalized release rates of the elements in TRPO waste are kept in a low value below 10 −4 g m −2 d −1 . La shows the highest normalized release rate of all the involved elements, while Zr exhibits the best chemical stability.
危险品化学品经营许可证（带存储）