Reactive transport models of the geochemical interactions at the iron/bentonite interface in laboratory corrosion tests

IF 5.3 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science Pub Date : 2023-08-01 DOI:10.1016/j.clay.2023.106981

Alba Mon , Javier Samper , Luis Montenegro , María Jesús Turrero , Elena Torres , Jaime Cuevas , Raúl Fernández , Laurent De Windt

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引用次数: 1

Abstract

Carbon steel and compacted bentonite have been proposed as candidate materials for the overpack and buffer, respectively, of the multi-barrier system of a geological high-level radioactive waste repository. Carbon steel corrosion may impair bentonite properties. The interactions of corrosion products and bentonite are analyzed with laboratory corrosion tests. Here coupled thermo-hydro-chemical-mechanical (THCM) models of two types of heating and hydration tests performed on compacted bentonite in contact with Fe powder are presented to study the iron-bentonite interactions at representative repository conditions. Tests on small cells (SC) were performed under unsaturated non-isothermal conditions in 25 mm long columns containing 21 mm of bentonite and 4 mm of Fe powder. Tests on medium-size cells (FB) were performed under unsaturated non-isothermal conditions in 99.8 mm long columns containing 86.8 mm of bentonite and 13 mm of Fe powder. Model results for the SC tests showed that magnetite and Fe(OH)₂(s) were the main corrosion products which compete for Fe²⁺ precipitation. Computed corrosion products precipitate mainly in the Fe powder, penetrate a few mm into the bentonite and reproduce the measured iron weight data. Model results of the FB tests showed that magnetite precipitates throughout the Fe powder interface and reproduce the main trends of the corrosion products. Model results of these corrosion tests will be of great relevance for the performance assessment of engineered barriers of radioactive waste repositories.

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实验室腐蚀试验中铁/膨润土界面地球化学相互作用的反应输运模型

提出了用碳钢和压实膨润土分别作为地质高放废物处置库多屏障系统包覆层和缓冲层的候选材料。碳钢的腐蚀会影响膨润土的性能。通过室内腐蚀试验，分析了腐蚀产物与膨润土的相互作用。本文采用热-水-化学-力学(THCM)耦合模型对与铁粉接触的压实膨润土进行了两种加热和水化试验，研究了具有代表性的储存库条件下铁-膨润土的相互作用。小细胞(SC)的测试在不饱和非等温条件下进行，在25毫米长的柱中含有21毫米的膨润土和4毫米的铁粉。在不饱和非等温条件下，在含有86.8 mm膨润土和13 mm铁粉的99.8 mm长柱中对中型细胞(FB)进行了测试。SC试验的模型结果表明，磁铁矿和Fe(OH)2(s)是竞争Fe2+沉淀的主要腐蚀产物。计算得到的腐蚀产物主要沉淀在铁粉中，向膨润土中渗透几毫米，重现了铁重的测量数据。模拟结果表明，铁粉界面有磁铁矿析出，重现了腐蚀产物的主要趋势。这些腐蚀试验的模型结果将对放射性废物贮存库工程屏障的性能评估具有重要意义。

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

Applied Clay Science 地学-矿物学

CiteScore

10.30

自引率

10.70%

发文量

289

审稿时长

39 days

期刊介绍： Applied Clay Science aims to be an international journal attracting high quality scientific papers on clays and clay minerals, including research papers, reviews, and technical notes. The journal covers typical subjects of Fundamental and Applied Clay Science such as: • Synthesis and purification • Structural, crystallographic and mineralogical properties of clays and clay minerals • Thermal properties of clays and clay minerals • Physico-chemical properties including i) surface and interface properties; ii) thermodynamic properties; iii) mechanical properties • Interaction with water, with polar and apolar molecules • Colloidal properties and rheology • Adsorption, Intercalation, Ionic exchange • Genesis and deposits of clay minerals • Geology and geochemistry of clays • Modification of clays and clay minerals properties by thermal and physical treatments • Modification by chemical treatments with organic and inorganic molecules(organoclays, pillared clays) • Modification by biological microorganisms. etc...