Influence of accessory phases and surrogate type on accelerated leaching of zirconolite wasteforms
Influence of accessory phases and surrogate type on accelerated leaching of zirconolite wasteforms
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副相和替代物类型对锆英石废料加速浸出的影响
DOI：
10.1038/s41529-021-00171-8
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发表时间：
2021
影响因子：
5.1
通讯作者：
Blackburn L
中科院分区：
文献类型：
--
作者：
Blackburn L
英国钚库存的一部分可能在处置前固定在锆英石陶瓷基质中。两个锆英石组合物，针对CaZr0.80Ce0.20Ti2O7和CaZr0.80U0.20Ti2O7，通过热等静压制，旁边的重新配制的组合物，标称Ca0.80Zr0.90Ce0.30Ti1.60Al0.40O7，与过量的Ti和Zr添加到排除形成的辅助钙钛矿相。材料在90 °C的各种酸性和碱性介质中进行加速浸出，累计时间为14天。从暴露于1M H2SO4的CaZr0.80Ce0.20Ti2.00O7测量到最大的Ce释放，其中14.7 ± 0.2%的原始Ce存量从废物形式释放到溶液中。Ce浸出到溶液中的程度与废物中存在的钙钛矿的量相关，并且与Ce 3+的掺入和优先溶解相关。CaZr0.80U0.20Ti2.00O7的抗浸出性能优于CaZr0.80Ce0.20Ti2.00O7，这归因于辅助钙钛矿的比例降低，在8 M HNO3中7 d后有7.1 ± 0.1%的U被释放。没有辅助钙钛矿相的Ca0.80Zr0.90Ce0.30Ti1.60Al0.40O7组合物呈现出显著改善的浸出特性，在8 M HNO3和1 M H2SO4中释放< 0.4%Ce。这些数据表明，需要仔细的成分设计的锆英石废物方面的辅助相的形成和替代品的选择。
A fraction of the UK Pu inventory may be immobilised in a zirconolite ceramic matrix prior to disposal. Two zirconolite compositions, targeting CaZr0.80Ce0.20Ti2O7and CaZr0.80U0.20Ti2O7, were fabricated by hot isostatic pressing, alongside a reformulated composition, nominally Ca0.80Zr0.90Ce0.30Ti1.60Al0.40O7, with an excess of Ti and Zr added to preclude the formation of an accessory perovskite phase. Materials were subjected to accelerated leaching in a variety of acidic and alkaline media at 90 °C, over a cumulative period of 14 d. The greatest Ce release was measured from CaZr0.80Ce0.20Ti2.00O7exposed to 1 M H2SO4, for which 14.7 ± 0.2% of the original Ce inventory was released from the wasteform into solution. The extent of Ce leaching into the solution was correlated with the quantity of perovskite present in the wasteform, and associated with the incorporation and preferential dissolution of Ce3+. CaZr0.80U0.20Ti2.00O7exhibited improved leach resistance relative to CaZr0.80Ce0.20Ti2.00O7, attributed to the decreased proportion of accessory perovskite, with 7.1 ± 0.1% U released to in 8 M HNO3after 7 d. The Ca0.80Zr0.90Ce0.30Ti1.60Al0.40O7composition, with no accessory perovskite phase, presented significantly improved leaching characteristics, with < 0.4%Ce released in both 8 M HNO3and 1 M H2SO4. These data demonstrate the need for careful compositional design for zirconolite wasteforms with regard to accessory phase formation and surrogate choice.
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DOI：
--
发表时间：
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期刊：
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影响因子：
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