An internally consistent thermodynamic dataset for aqueous species in the system Ca-Mg-Na-K-Al-Si-O-H-C-Cl to 800 °C and 5 kbar
An internally consistent thermodynamic dataset for aqueous species in the system Ca-Mg-Na-K-Al-Si-O-H-C-Cl to 800 °C and 5 kbar
复制标题
Ca-Mg-Na-K-Al-Si-O-H-C-Cl 系统中水性物质在 800 °C 和 5 kbar 下的内部一致热力学数据集
DOI：
--
复制
发表时间：
2017
影响因子：
2.9
通讯作者：
B. Lothenbach
中科院分区：
文献类型：
--
作者：
G. Miron;Thomas Wagner;D. Kulik;B. Lothenbach
本研究提供了Ca-Mg-Na-K-Al-Si-O-H-C-Cl体系中水相物种的内部一致热力学数据集，该数据集是通过向核心体系Na-K-Al-Si-O-H-Cl中添加钙、镁和碳物种获得的(MIron等人，2016)。在广泛的温度和压力范围内，对矿物(钙和镁氢氧化物、钙和镁硅酸盐、钙长石、钙和镁碳酸盐)在水和电解质水溶液中的溶解度进行了严格评估的实验数据被添加到实验数据数据库中。然后使用完整的实验数据集在修正的Helgeson-Kirkham-Flowers(HKF)状态方程的框架内同时精炼所有水离子和络合物的标准态Gibbs能量。溶解度控制矿物的热力学性质接受自Holland和Powell的内部一致数据集(1998年；更新的Thermocalc数据集ds55)。评述了重要的氢氧化物、氯化物、碳酸盐和硅酸盐络合物的缔合平衡，它们的标准态性质和HKF参数独立地由电导、电位法和少数情况下的溶解度测量得出。在用GEMSFITS程序(MIron等人，2015)对水相物种的标准吉布斯能进行的全局优化中，水相络合物的缔合平衡始终保持不变。新的热力学数据集再现了Ca-Mg-Na-K-Al-Si-O-H-C-Cl体系中所有可用的流体-矿物相平衡和矿物溶解度数据，在温度(25-800°C)、压力(1bar-5kbar)和组成(盐浓度最高可达5摩尔)的广泛范围内都具有良好的准确性。这使得能够以前所未有的精度和可靠性在各种条件下对天然和工程地质储集层中的过程进行地球化学和反应输运模拟，并从一个新的角度研究地壳中的流体流动和流体-岩石相互作用过程。使用与本研究相同的策略，内部一致的热力学数据集可以进一步扩展，添加更多的主元素和微量元素，当有新的实验数据或新一代水溶液状态方程或活度模型可用时，可以重复数据改进过程。
This study presents an internally consistent thermodynamic dataset for aqueous species in the system Ca-Mg-Na-K-Al-Si-O-H-C-Cl, obtained by adding species of calcium, magnesium and carbon to the core system Na-K-Al-Si-O-H-Cl (Miron and others, 2016). Critically evaluated experimental data on mineral solubility (Ca and Mg hydroxides, Ca and Mg silicates, anorthite, Ca and Mg carbonates) in water and aqueous electrolyte solutions over wide ranges in temperature and pressure were added to the database of experimental data. The complete experimental dataset was then used to simultaneously refine the standard state Gibbs energies of all aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers (HKF) equation of state. The thermodynamic properties of the solubility-controlling minerals were accepted from the internally consistent dataset of Holland and Powell (1998; updated Thermocalc dataset ds55). The association equilibria of important hydroxide, chloride, carbonate and silicate complexes were critically reviewed, and their standard state properties and HKF parameters were independently derived from conductance, potentiometric and, in a few cases, solubility measurements. In a global optimization of standard Gibbs energies of aqueous species, performed with the GEMSFITS code (Miron and others, 2015), the association equilibria for aqueous complexes were always maintained. The new thermodynamic dataset reproduces all available fluid-mineral phase equilibria and mineral solubility data in the system Ca-Mg-Na-K-Al-Si-O-H-C-Cl with good accuracy over wide ranges in temperature (25–800 °C), pressure (1 bar – 5 kbar) and composition (salt concentrations up to 5 molal). This makes it possible to perform geochemical and reactive transport modeling of processes in natural and engineered georeservoirs over wide ranges of conditions with an unprecedented level of accuracy and reliability and to address processes of fluid flow and fluid-rock interaction in the Earth's crust from a new perspective. Using the same strategy as applied in the present study, the internally consistent thermodynamic dataset can be further extended with additional major and trace elements, and the data refinement process can be repeated when new experimental data or next-generation equation of state or activity models for aqueous solutions become available.