Solubility of anhydrite in supercritical water from 380 ˚C to 625 ˚C and 220 bar to 270 bar

IF 5 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Geochimica et Cosmochimica Acta Pub Date : 2025-10-01 DOI:10.1016/j.gca.2024.09.030

Pedro M. Rendel, Bruce W. Mountain, Lucjan Sajkowski

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引用次数: 0

Abstract

The solubility of anhydrite in deionized water has been determined experimentally from 380 ˚C to 625 ˚C and 220 bar to 270 bar. The experiments were performed using a unique flow-through reactor capable of reaching supercritical conditions for pure water. The results cover the approximate range of temperature and pressure expected to be found in deep geothermal systems where supercritical conditions could be expected. Anhydrite solubility has not been previously well-defined in this region.

The new experimental data are used to define empirical parameters for a new thermodynamic model based on Dolejš and Manning (2010), for anhydrite dissolution in silica-bearing aqueous fluids at elevated temperatures and pressures:

- R T \ln m = a + b + e l n ρ_{w}

where m is the molar concentration mol∙kg⁻¹, R is the gas constant in J mol⁻¹ K⁻¹, and ρ_w is the density of pure water in kg m⁻³. These parameters only apply in solutions containing silica and at fluid densities above 200 kg m⁻³:

a = 14921.46; b = 369.46; e = -48.81.

T is temperature in K.

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硬石膏在380℃~ 625℃、220 bar ~ 270 bar超临界水中的溶解度

实验测定了硬石膏在去离子水中的溶解度，温度范围380℃~ 625℃，温度范围220 bar ~ 270 bar。实验是使用一种独特的流动反应器进行的，该反应器能够达到纯水的超临界条件。结果涵盖了在深部地热系统中可能出现超临界条件的温度和压力的大致范围。硬石膏的溶解度以前在这个地区没有明确的定义。利用新的实验数据定义了基于Dolejš and Manning（2010）的高温高压含硅水溶液中硬石膏溶解的新热力学模型的经验参数：-RTlnm=a+b+elnρ，其中m为摩尔浓度mol∙kg−1，R为气体常数J mol−1 K−1，ρw为纯水密度kg m−3。这些参数仅适用于含有二氧化硅的溶液和流体密度高于200 kg m - 3:a = 14921.46；b = 369.46；e = -48.81。T是温度，单位是K。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geochimica et Cosmochimica Acta 地学-地球化学与地球物理

CiteScore

9.60

自引率

14.00%

发文量

437

审稿时长

6 months

期刊介绍： Geochimica et Cosmochimica Acta publishes research papers in a wide range of subjects in terrestrial geochemistry, meteoritics, and planetary geochemistry. The scope of the journal includes: 1). Physical chemistry of gases, aqueous solutions, glasses, and crystalline solids 2). Igneous and metamorphic petrology 3). Chemical processes in the atmosphere, hydrosphere, biosphere, and lithosphere of the Earth 4). Organic geochemistry 5). Isotope geochemistry 6). Meteoritics and meteorite impacts 7). Lunar science; and 8). Planetary geochemistry.