Rheinheimer Vanessa, Unluer Cise, Liu Jiawei, Ruan Shaoqin, Pan Jisheng, Monteiro Paulo J M
Berkeley Education Alliance for Research in Singapore, Singapore 138602, Singapore.
Department of Civil and Environmental Engineering, Nanyang Technical University, Singapore 639798, Singapore.
Materials (Basel). 2017 Jan 18;10(1):75. doi: 10.3390/ma10010075.
MgO cements have great potential for carbon sequestration as they have the ability to carbonate and gain strength over time. The hydration of reactive MgO occurs at a similar rate as ordinary Portland cement (PC) and forms brucite (Mg(OH)₂, magnesium hydroxide), which reacts with CO₂ to form a range of hydrated magnesium carbonates (HMCs). However, the formation of HMCs within the MgO-CO₂-H₂O system depends on many factors, such as the temperature and CO₂ concentration, among others, which play an important role in determining the rate and degree of carbonation, the type and stability of the produced HMCs and the associated strength development. It is critical to understand the stability and transformation pathway of HMCs, which are assessed here through the use of X-ray photoelectron spectroscopy (XPS). The effects of the CO₂ concentration (in air or 10% CO₂), exposure to high temperatures (up to 300 °C) and curing period (one or seven days) are reported. Observed changes in the binding energy (BE) indicate the formation of different components and the transformation of the hydrated carbonates from one form to another, which will influence the final performance of the carbonated blends.
氧化镁水泥在碳封存方面具有巨大潜力，因为它们能够碳酸化并随着时间推移增强强度。活性氧化镁的水化速率与普通硅酸盐水泥（PC）相似，并形成水镁石（Mg(OH)₂，氢氧化镁），水镁石与二氧化碳反应形成一系列水化碳酸镁（HMCs）。然而，MgO-CO₂-H₂O体系中HMCs的形成取决于许多因素，如温度和二氧化碳浓度等，这些因素在决定碳酸化速率和程度、所产生HMCs的类型和稳定性以及相关强度发展方面起着重要作用。了解HMCs的稳定性和转化途径至关重要，本文通过使用X射线光电子能谱（XPS）对其进行评估。报告了二氧化碳浓度（空气中或10%二氧化碳）、高温暴露（高达300°C）和养护期（一天或七天）的影响。观察到的结合能（BE）变化表明不同组分的形成以及水化碳酸盐从一种形式到另一种形式的转变，这将影响碳酸化混合物的最终性能。
