Hydrotalcite-pyroaurite solid solution in cement system: Molecular structure and thermodynamic properties

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research Pub Date : 2025-06-26 DOI:10.1016/j.cemconres.2025.107976

Dengquan Wang , Yue Zhang , John L. Provis , Barbara Lothenbach , Sergey V. Churakov , George-Dan Miron , Zeyu Zhou , Jing Guan , Jiaxing Ban , Bin Ma

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引用次数: 0

Abstract

Hydrotalcite-pyroaurite solid solutions, which are common minerals both in nature and in modern cementitious materials, hold significant potential for waste immobilization and cement properties yet remain insufficiently studied. In this work, we first synthesized a series of hydrotalcite (Mg₆Al₂(OH)₁₆CO₃·nH₂O) and pyroaurite (Mg₆Fe₂(OH)₁₆CO₃·nH₂O) solid solutions and conducted comprehensive characterizations. Synchrotron-based X-ray absorption spectroscopy was further employed to elucidate the molecular structure, while molecular simulations explored changes in charge density induced by Fe substitution. The results reveal that Fe substitution for Al reduces the thermal stability and induces structural changes. Specifically, the larger ionic radius of Fe³⁺ compared to Al³⁺ increases the unit cell parameters and elongates the FeO and FeMg distances in the local structure. Fe substitution also leads to localized positive charge accumulation within the layer. Additionally, thermodynamic parameters were obtained, and a solid solution model was established to supplement the existing thermodynamic database.

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水滑石-焦金石在水泥体系中的固溶体：分子结构和热力学性质

水滑石-辉钼矿固溶体是自然界和现代胶凝材料中常见的矿物，在废物固定化和水泥性能方面具有重要的潜力，但研究还不够充分。在这项工作中，我们首先合成了一系列水滑石（Mg6Al2(OH)16CO3·nH2O）和辉钼矿（Mg6Fe2(OH)16CO3·nH2O）固溶体，并进行了综合表征。基于同步加速器的x射线吸收光谱进一步阐明了分子结构，而分子模拟则探索了铁取代引起的电荷密度变化。结果表明，Fe取代Al降低了材料的热稳定性并引起结构变化。具体来说，Fe3+的离子半径比Al3+大，增加了单元胞参数，延长了局部结构中FeO和FeMg的距离。铁取代也导致层内局部正电荷积累。此外，还获得了热力学参数，并建立了固溶体模型，以补充现有热力学数据库。

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来源期刊

Cement and Concrete Research 工程技术-材料科学：综合

CiteScore

20.90

自引率

12.30%

发文量

318

审稿时长

53 days

期刊介绍： Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.