Speciation of yttrium in fluorine-rich brines at hydrothermal and metamorphic conditions

热液和变质条件下富氟盐水中钇的形态

• 批准号: 389260343
• 负责人: Professor Dr. Sandro Jahn
• 金额: --
• 依托单位: Institut für Geologie und Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/389260343?language=en
• 关键词: Speciation; yttrium; fluorine; rich; brines

Aqueous fluids play an important role in many geological processes. They are major transport media of chemical elements in hydrothermal and metamorphic environments. Despite this importance, the thermodynamic properties of such fluids at high temperatures and pressures are not well known. One important group of elements dissolved in and transported by fluids are the rare earth elements. Molecular modeling approaches based on quantum mechanics have become a powerful and predictive tool to study the structure and thermodynamic properties of complex fluids at the same time. Here, we propose to use ab initio molecular simulations to develop speciation models of yttrium in chlorine- and fluorine-bearing fluids. Ab initio molecular dynamics simulations will be complemented by metadynamics and thermodynamic integration methods to predict the stability constants of different solute species as a function of composition, temperature and pressure. This information will be used to construct majority species diagrams and to make predictions of Y-bearing mineral solubilities in Cl- and F-bearing geological fluids. The simulations will also provide new molecular-scale insight into the transport mechanisms of rare earth elements by hydrothermal or metamorphic fluids and the deposition of related minerals.

含水流体在许多地质过程中起着重要的作用。它们是热液和变质环境中化学元素的主要输运介质。尽管这很重要，但这类流体在高温和高压下的热力学性质还不是很清楚。溶解在流体中并由流体输送的一组重要元素是稀土元素。基于量子力学的分子模拟方法已成为同时研究复杂流体结构和热力学性质的强有力的预测工具。在这里，我们建议使用从头算分子模拟来建立Y在含氯和含氟流体中的形态模型。从头算分子动力学模拟将与元动力学和热力学积分方法相补充，以预测不同溶质物种的稳定常数随组成、温度和压力的变化。这些信息将被用来构建大多数物种图解，并预测含Y矿物在含氯和含氟地质流体中的溶解度。这些模拟还将提供新的分子尺度洞察稀土元素在热液或变质流体中的迁移机制以及相关矿物的沉积。

项目成果

Yttrium speciation in subduction-zone fluids from ab initio molecular dynamics simulations

• DOI: 10.5194/se-11-767-2020
• 发表时间: 2020-05
• 期刊: Solid Earth
• 影响因子: 3.4
• 作者: J. Stefanski;S. Jahn