Collaborative Research: Experimental Determination of REE-Chloride Complex Stability Constants and Monazite Solubilities in Hydrothermal Solutions

合作研究：稀土-氯化物络合物稳定性常数和独居石在热液中溶解度的实验测定

• 批准号: 9714631
• 负责人: Christopher Gammons
• 金额: $ 8.15万
• 依托单位: Montana Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-15 至 2000-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9714631&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Determination; REE

9714631 Gammons Knowledge of the behavior of the rare earth elements (REE) in high temperature water solutions is required in the following areas: 1) geochronology (i.e., rock dating); 2) REE ore deposit geology; and 3) remediation and safe storage of nuclear waste . Unfortunately, there is a lack of the relevant data required for a better understanding of REE geochemistry. It is expected that the REE will form a dissolved complex with the chloride ion in many natural solutions, and it is known that REE phosphate phases (monazite, xenotime, rhabdophane) are common REE minerals. Thus, the objectives of this proposal are to: 1) determine the solubility of monazite/xenotime in hydrothermal solutions up to 350(C; 2) determine the stoichiometries and stabilities of REE chloride complexes up to 350(C; and 3) apply our experimental data to problems related to the mobility of REE during water-rock interaction. The data obtained in this study will resolve discrepant theoretical estimates in the literature, provide one of the first experimentally derived sets of thermodynamic data for REE complexes at elevated temperatures, permit quantitative modeling of the role of REE chloride complexes in REE mobility, and serve as a basis for improved theoretical predictions of stability constants for other REE complexes for use until additional experimental data become available. During the course of this project, one graduate and one undergraduate student will be trained in hydrothermal experimental techniques, a number of modern analytical methods, and various aspects of aqueous geochemistry relevant to studies in economic geology and environmental geochemistry. In addition, a new experimental geochemistry laboratory will be set up at Montana Tech.

9714631 Gammons 以下领域需要了解稀土元素 (REE) 在高温水溶液中的行为： 1) 地质年代学（即岩石测年）； 2）稀土矿床地质； 3）核废料的修复和安全储存。不幸的是，缺乏更好地了解稀土元素地球化学所需的相关数据。预计稀土元素将与许多天然溶液中的氯离子形成溶解的络合物，并且已知稀土元素磷酸盐相（独居石、磷钇矿、斜纹石）是常见的稀土元素矿物。因此，本提案的目标是：1) 确定独居石/磷钇矿在高达 350(C) 的热液中的溶解度；2) 确定 REE 氯化物复合物在高达 350(C) 的化学计量和稳定性；3) 应用我们的水-岩相互作用过程中稀土元素迁移率相关问题的实验数据。本研究中获得的数据将解决文献中不一致的理论估计，提供第一组实验得出的高温下 REE 复合物的热力学数据集之一，允许对 REE 氯化物复合物在 REE 迁移率中的作用进行定量建模，并作为为其他 REE 复合物的稳定性常数的改进理论预测提供基础，以便在获得更多实验数据之前使用。在该项目期间，一名研究生和一名本科生将接受水热实验技术、多种现代分析方法以及与经济地质学和环境地球化学研究相关的水地球化学各个方面的培训。此外，蒙大拿理工学院还将设立一个新的实验地球化学实验室。