Self-propagating high-temperature synthesis of CeO2 incorporated zirconolite-rich waste forms and the aqueous durability
Self-propagating high-temperature synthesis of CeO2 incorporated zirconolite-rich waste forms and the aqueous durability
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DOI：
10.1016/j.jeurceramsoc.2015.04.025
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发表时间：
2015-10
影响因子：
5.7
通讯作者：
Kuibao Zhang;Guanjun Wen;Haibin Zhang;Yuancheng Teng
中科院分区：
文献类型：
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作者：
Kuibao Zhang;Guanjun Wen;Haibin Zhang;Yuancheng Teng
以Ca(NO3)2为氧化剂，Ti为还原剂，采用自蔓延高温快速压制法（SHS/QP）快速合成了富含锆石的Synroc废体。以2m -锆石（CaZrTi2O7）为主要相，钙钛矿（CaTiO3）和焦绿石（Ca2Ti2O6）为次要相。作为四价锕系核素的替代品，加入了高达50% at%的ceo2来取代锆石的Zr位点。随着ceo2添加量的增加，锆石的重量分数逐渐降低，钙钛矿的重量分数逐渐增加。Ce主要被掺入钙钛矿和ca2ti2o6焦绿石的Ca位点，而不是锆石的Zr位点。含ce的Synroc废物形态表现出较高的水热稳定性。mc1浸出试验表明，Ca和Ce的标准化浸出率（42 d）分别为0.49 g m−2d−1和9.47 × 10−6g m−2d−1。
Zirconolite-rich Synroc waste forms were rapidly synthesized by self-propagating high-temperature plus quick pressing (SHS/QP) using Ca(NO3)2as the oxidant and Ti as the reductant. 2M-zirconolite (CaZrTi2O7) was produced as the major phase with perovskite (CaTiO3) and pyrochlore (Ca2Ti2O6) as minor phases. As the surrogate of tetravalent actinide nuclides, up to 50 at% CeO2was incorporated to substitute the Zr site of zirconolite. The weight fraction of zirconolite decreases gradually while the perovskite proportion increases when the CeO2addition is promoted. Ce was mostly incorporated into the Ca sites of perovskite and Ca2Ti2O6pyrochlore, rather than the assumed Zr site of zirconolite. The Ce-bearing Synroc waste form exhibits high hydrothermal stability. The MCC-1 leaching test shows the normalized leaching rates (42 d) of Ca and Ce are 0.49 g m−2d−1and 9.47 × 10−6g m−2d−1.