Phase evolution and chemical stability of Nd-doped natural garnet waste form by microwave sintering

Xu, Beibei; Zhang, Shengtai; wang, Lingkun; Huang, Ping; Zeng, Chuan; Zheng, Caohui; Ding, Yi; Ji, Shiyin; Xiong, Ying; Duan, Tao

doi:10.1016/j.ceramint.2022.03.071

Cited by 5 publications

(3 citation statements)

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“…In contrast to the deionized water, weakly alkaline leaching agents will also promote the dissolution of the ceramic waste form, 50 which can lead to a slight enhancement of the normalized leaching rate of Nd. The leaching resistance of zirconia/garnet multi-phase ceramics waste forms with other ceramic waste forms was further compared, including widely studied single-phase ceramics 9,11,[50][51][52] and some multiple-phase ceramics, 17,19 the specific data are shown in Figure 8. The results showed that zirconia/garnet multi-phase ceramics exhibited superior chemical stability.…”

Section: Leaching Experimentsmentioning

confidence: 99%

“…For example, zircon has high selectivity and poor adaptability for nuclides, and its immobilization capacity for actinides is low 17 . In our previous study, 9 calcium garnet waste form (Ca 1.5 Nd 1.5 Zr 1.5 Fe 0.5 Fe 3 O 12 ) has shown excellent performance in many aspects. However, owing to crystal structure characteristics, a variety of ceramic substrates including calcium garnet tend to have only one or two lattice sites that can be replaced by actinides, thus limiting the immobilization of highly radioactive wastes with complex compositions 18 .…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the immobilization of HLW with substrates such as cement, glass, and ceramics, followed by geological disposal, has been considered to be a technically feasible and safe way to manage nuclear waste in the long‐term 7,8 . Ceramics matrices, such as garnet, 9,10 pyrochlore, 11 zircon, 12 britholite, 13 have previously been investigated due to their superior properties compared with glass waste forms in regard to their chemical, thermal, and radiation resistances 14–16 . However, these materials also have certain limitations.…”

Section: Introductionmentioning

confidence: 99%

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Zirconia/garnet multiphase ceramics with high immobilization capacity for Nd confers better physical and chemical stability

Ge,

Xu,

Liao

et al. 2023

J Am Ceram Soc.

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Multiphase ceramics have a high application potential in the field of nuclear waste immobilization because of the efficient synergy between the individual phases. In this work, zirconia/garnet multiphase ceramics with high efficient and effective immobilization capacity of trivalent actinides were successfully prepared using conventional solid‐phase sintering. ZrO2 doping increases the lattice site available for nuclide substitution and advance the immobilization capacity of the ceramic substrate for nuclide. At the same time, the phase change of zirconia is used to tougher and improve the physical properties of the ceramic waste form. The feasibility of using multiphase ceramics for the efficient immobilization of trivalent actinides was assessed by studying the phase evolution, microstructure, Vickers hardness, and chemical stability of the multi‐phase ceramics. Zr1‐xNdxO2‐x/2/Ca3‐yNdyZr3‐yFey‐1Fe3O12 multiphase ceramics exhibited superior physical or chemical properties compared to most of the multiphase ceramics as well as the previously prepared single‐phase calcium garnet ceramic waste forms. The Vickers hardness of all the multiphase ceramic samples ranged between 685 and 730 HV0.5. Under the condition of using simulate Bei Shan groundwater as leaching agent, the normalized leaching rates of Nd is approximately 10−6 g·m−2·day−1, showing good chemical stability and achieving efficient and effective immobilization of trivalent actinides. The excellent chemical, as well as physical properties of Zr1‐xNdxO2‐x/2/Ca3‐yNdyZr3‐yFey‐1Fe3O12 multiphase ceramics are expected to make them one of the substrates for more efficient and effective immobilizing of trivalent actinides.

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