The effect of interlayer cations on the expansion of vermiculite

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• 作者：Xiaoxu Huo ; Limei Wu ; Libing Liao ; ^{lbliao@cugb.edu.cn} ; Zhiguo Xia ; Lijuan Wang
• 关键词：Crystal structure ; Thermal expansion ; X-ray diffraction ; Differential thermal analysis
• 刊名：Powder Technology
• 出版年：2012
• 期刊代码：144_00325910
• 类别：et
• 出版时间：July, 2012
• 卷：224
• 期：Complete
• 页码：241-246
• 文件大小：915 K

摘要

Three kinds of salt solutions including NaCl, CaCl₂ and MgCl₂, were used to modify the expansion of vermiculite. X-ray diffraction results indicate that vermiculites have been successfully modified by salt solutions. The d₍₀₀₂₎ reflection spacings of Na-vermiculite, Ca-vermiculite and Mg-vermiculite corresponding to different salt solution modifications are 1.223 nm, 1.474 nm and1.448 nm, respectively. Expansion ratio experiment results show that the as-obtained vermiculite modified by NaCl solution can lower the beginning expansion temperature, while the vermiculites modified by CaCl₂ and MgCl₂ solutions can show high expansion ratio. The combined thermogravimetric-differential thermal analysis and infrared spectroscopy analysis reveal that electrostatic attraction force between interlayer cations and interlayer water plays the key factor in the expansion ratio of vermiculite. Compared with Ca and Mg cations, the electrostatic attraction force between Na cation and interlayer water is weak and Na-vermiculite has less interlayer water than that of Ca-vermiculite and Mg-vermiculite.