Si／Al比对水热法合成皂石结构的影响  

Structural Characteristics of Hydrothermally Synthesized Saponites with Different Si/Al Ratios

作　　者：李甜[1,2] 陶奇[1] 何宏平[1] 朱建喜[1] 袁鹏[1] 苏琳娜[1,2] 

机构地区：[1]中国科学院矿物学与成矿学重点实验室,中国科学院广州地球化学研究所,广州510640 [2]中国科学院研究生院,北京100049

出　　处：《硅酸盐学报》2013年第1期110-114,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学(U0933003,41002015)基金项目;国家科技支撑计划(2011BAB03B06)基金项目

摘　　要：水热法合成的皂石,其结构特性除受到时间、温度、pH值等参数的影响外,还与铝的占位与配位形式有着直接的联系。作为一个特殊的骨架离子,铝对皂石物相的纯度、结构稳定性以及表面反应性等都起着至关重要的作用。采用水热法,固定初始物料中镁的添加量,硅与铝的添加量之和为一定值,改变Si/Al比(摩尔比),制备了一系列皂石,探究铝元素在皂石中的存在形式和微结构环境。X射线衍射分析表明:铝的添加量对皂石的结晶度有着重要的影响,当Si/Al比为5.43～12.30时,皂石结晶良好。29Si、27Al NMR谱研究表明:在皂石的形成过程中,铝离子和镁离子分别优先进入四面体和八面体晶格中,当Si/Al比为2.33～1.80时,铝离子进入八面体中的含量明显增多;合成皂石片层中普遍存在SiIV悬键,并出现Q2Si(OAl)信号,这与天然蒙皂石的NMR谱存在明显的区别。A series of saponites were synthesized with fixed contents of magnesium, certain amounts of silicon and aluminum and various Si/Al ratios in a starting gel by a hydrothermal method. The influences of parameters （i.e., chemical composition, crystallization time, pH value and temperature） on the structure of saponite in the synthesis process were investigated. Aluminum as a special skeleton cation could affect the morphology, textural and surface properties. The X-ray diffraction patterns showed that the well-crystallized saponite could be obtained in the Si/Al ratio range from 5.43-12.30. The 29Si and 27Al NMR spectra suggested that aluminum and magnesium were prior to enter tetrahedral and octahedral sites, respectively. The incorporation of aluminum cation in six-fold coordination was favored in the Si/Al ratio range of 2.33-1.80. Q2 Si（OAl） was observed in the cases of high contents of Si4＋, corresponding to Si located at the edges of saponite. This was different from natural clay minerals, i.e., Q2 Si（OAl） is hardly detected in the natural smectites.

关 键 词：皂石 水热合成 配位 四面体 八面体 

分 类 号：P579[天文地球—矿物学]