Kui Liu,Kuibao Zhang,Ting Deng,Jianjun Zeng,Baozhu Luo,Haibin Zhang
Gd 2 Zr 2 O 7 ceramic is considered as one of the most promising host minerals for the immobilization of high-level radioactive wastes . Here, the effects of grain size on the aqueous durability of Gd 2 Zr 2 O 7 ceramics were studied. Two kinds of leaching experiments were used to research Gd 2 Zr 2 O 7 ceramic powders and bulks with different grain sizes (5 nm, 78 nm, 1 μm and 18 μm). The results demonstrate that the normalized leaching rates decrease with the increase of grain size. Through characterization and analysis, it is concluded that the hydrolysis reactions of Gd 2 Zr 2 O 7 occur in the leaching experiment and the hydrolysates are Gd(OH) 3 and Zr(OH) 4 . Besides, all the samples after leaching exhibit slight lattice contraction, which decreases with the increase of crystal grain size. The influence of leaching on the elemental distribution is most significant for the sample with grain size of 5 nm. This study has theoretical guiding significance for the application of Gd 2 Zr 2 O 7 immobilization.
Xiaofen Wang,Jiang Ma,Xirui Lu,Zhiwei Fang,Lingshuang Li,Linyan Li,Yushan Yang
Hollandite ceramics are considered as a promising host matrix for cesium immobilization. In the paper, [Cs x Ba y ][Fe 3+ 2 y + x Ti 4+ 8-2 y - x ]O 16 (0.3 ≤ x , y ≤ 0.75) ceramics were synthesized by solid-state reaction method using 133 Cs and 133 Ba as the substitutes for radioactive Cs and its daughter product Ba. It was found that the as-prepared (Cs,Ba)-hollandite solid solution shows a tetragonal structure ( I 4/m) with >90% crystallinity and good Cs retention at 1250 °C. Moreover, the normalized release rates of Cs and Ba are in the order of 10 −3 g m −2 d −1 for 28 days, exhibiting excellent aqueous durability.
危险品化学品经营许可证（带存储）