Multiparametric Dissolution of Thorium鈥揅erium Dioxide Solid Solutions

详细信息    查看全文

• 作者：Laurent Claparede ; Nicolas Clavier ; Nicolas Dacheux ; Adel Mesbah ; Julien Martinez ; St茅phanie Szenknect ; Philippe Moisy
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：November 21, 2011
• 年：2011
• 卷：50
• 期：22
• 页码：11702-11714
• 全文大小：1273K
• 年卷期：v.50,no.22(November 21, 2011)
• ISSN：1520-510X

文摘

The dissolution of Th_1鈥?i>xCe_xO₂ solid solutions samples prepared by thermal conversion of oxalate precursors was studied by varying independently several parameters (such as chemical composition, leachate acidity, leaching temperature, firing temperature, and crystallization state). The relative effects of these parameters on the normalized dissolution rate were examined. Either the obtained partial order related to the proton activity (n = 0.50 卤 0.01) or the activation energy (E_A = 57 卤 6 kJ.mol^鈥?) suggested that the dissolution was mainly driven by surface reactions occurring at the solid/liquid interface. Conversely to that observed for Th_1鈥?i>xU_xO₂ and Ce_1鈥?i>xNd_xO_2鈥?i>x/2 solid solutions, the chemical composition did not induce strong modifications of the chemical durability of the leached samples. While the initial normalized dissolution rate slightly depended on the elimination of crystal defects for firing temperatures below 800 掳C, it was mainly independent of the crystallite size (T 鈮?900 掳C). The role of crystal defects (then that of preparation conditions) appeared thus important to consider since they contributed to modifications of the normalized dissolution rates of the same order of magnitude than that of the leachate acidity.