CSLM study on the interaction of Nd₂O₃ with CaCl₂ and CaF₂–LiF molten melts

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• 作者：Abhishek Mukherjee ; Joris Van Dyck ; Bart Blanpain…
• 刊名：Journal of Materials Science
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：52
• 期：3
• 页码：1717-1726
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Materials Science, general; Characterization and Evaluation of Materials; Polymer Sciences; Continuum Mechanics and Mechanics of Materials; Crystallography and Scattering Methods; Classical Mechanics;
• 出版者：Springer US
• ISSN：1573-4803
• 卷排序：52

文摘

Neodymium is produced commercially by the fused salt electrolysis of Nd₂O₃–NdF₃–CaF₂–LiF melt. The efficiency of the process is low due to the limited solubility of Nd₂O₃ in the fluoride melt. The suitability of making Nd directly from Nd₂O₃ by the FFC Cambridge process seems very attractive. The basic requirements for FFC Cambridge process are that (a) the oxide should not dissolve in the molten salt (usually CaCl₂ or CaF₂–LiF) and (b) the decomposition potential of oxide should be below the decomposition potential of salt. The present study was to understand the first requirement. It reports for the first time the in situ chemical interactions of Nd₂O₃ with molten CaCl₂ and CaF₂–LiF using confocal scanning laser microscope. In molten CaCl₂, Nd₂O₃ reacts vigorously to form NdOCl. The product detaches from the parent Nd₂O₃ surface, exposing the oxide surface to further attack from molten CaCl₂. The reaction rate becomes faster as the temperature increases. In a molten CaF₂–LiF melt, Nd₂O₃ dissolves. Owing to the limited solubility of the oxide in CaF₂–LiF melt, the direct electroreduction may still proceed in an oxide-saturated CaF₂–LiF melt.