Combustion synthesis of Hf-doped zirconolite-rich composite waste forms and the aqueous durability
Abstract Zirconolite is recognized as one of the most durable waste matrices for the disposal of high-level radioactive wastes (HLWs). In this study, HfO2 was employed as the surrogate of tetravalent actinides. Hf-bearing zirconolite-based composite waste forms (CaZr1−x Hf x Ti2O7) were rapidly prep...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Tsinghua University Press
2019-07-01
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| Series: | Journal of Advanced Ceramics |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1007/s40145-019-0339-z |
| Summary: | Abstract Zirconolite is recognized as one of the most durable waste matrices for the disposal of high-level radioactive wastes (HLWs). In this study, HfO2 was employed as the surrogate of tetravalent actinides. Hf-bearing zirconolite-based composite waste forms (CaZr1−x Hf x Ti2O7) were rapidly prepared by combustion synthesis (CS) using CuO as the oxidant, where quick pressing (QP) was introduced to obtain densified samples. Similar as solid state reaction process, the Zr site of zirconolite can be totally occupied by Hf (x = 1.0) under the CS reaction. The original 2M zirconolite structure was maintained and a small amount of perovskite impurity phase was generated in the final products. The aqueous durability of representative sample (Cu-Hf-0.6) was tested, where the 42-day normalized leaching rates (LR i ) of Ca, Cu, and Hf are 0.25, 3.10×10−2, and 1.11×10−8 g·m−2·d−1. |
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| ISSN: | 2226-4108 2227-8508 |