Feng Jinpeng, Liu Meng, Fu Linzong, Zhang Kan, Xie Zhenhui, Shi Dawei, Ma Xin
School of Resources, Environment and Materials, Guangxi University Nanning 530004 PR China
RSC Adv. 2020 Feb 20;10(13):7635-7642. doi: 10.1039/d0ra00223b. eCollection 2020 Feb 18.
Aimed at improving vermiculite's thermal expansibility, a novel method of Na modification has been proposed. The modification effects were characterized X-ray fluorescence spectroscopy, X-ray diffraction, and thermogravimetric-differential thermal analysis. The result indicated that sodium ions entered vermiculite interlayers through the exchange of interlamellar calcium ions. The effects of the heating time on the expansion ratio of Raw-V and Na-V samples were investigated at the temperature range of 400-700 °C. The result indicated that the maximum increment in the expansion ratio could reach up to 26.5% after Na modification. The influencing mechanism of Na modification on the thermal expansibility of vermiculite was explored molecular dynamics simulation and the binding energy and dehydration enthalpy change calculation. The simulation and calculation results showed a good agreement with the expansion experiment result. This study provides a novel method for the preparation of high-performance expanded vermiculite.
为了提高蛭石的热膨胀性，提出了一种新的钠改性方法。通过X射线荧光光谱、X射线衍射和热重-差热分析对改性效果进行了表征。结果表明，钠离子通过层间钙离子的交换进入蛭石层间。在400-700℃温度范围内研究了加热时间对原蛭石（Raw-V）和钠改性蛭石（Na-V）样品膨胀率的影响。结果表明，钠改性后膨胀率的最大增幅可达26.5%。通过分子动力学模拟以及结合能和脱水焓变计算，探讨了钠改性对蛭石热膨胀性的影响机制。模拟和计算结果与膨胀实验结果吻合良好。本研究为高性能膨胀蛭石的制备提供了一种新方法。
