Characterization of Synthetic Na-Beidellite
Characterization of Synthetic Na-Beidellite
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DOI：
10.1346/ccmn.1990.0380410
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发表时间：
1990-08
影响因子：
2.2
通讯作者：
J. T. Kloprogge;J. Jansen;J. Geus
中科院分区：
文献类型：
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作者：
J. T. Kloprogge;J. Jansen;J. Geus
钠-贝得石是蒙皂石族的一员，由组成为0.35Na2O·2.35Al2O3·7.3SiO2的凝胶在NaOH溶液中在pH值为7.5至13.5、压力为1 kbar和温度为350°C的条件下水热生长。采用扫描电子显微镜、X射线粉末衍射、红外光谱、电子探针、电感耦合等离子体原子发射光谱和热重分析等手段对合成的钠贝得石进行了表征。正交晶胞的晶胞参数为：a = 5.18，B = 8.96，c = 12.54 Ω。阳离子交换容量测定为70 meq/100 g。最多40 wt. %的水存在并且通过加热至约55°C可逆地损失。水分的损失导致基间距减小至9.98 μ m。在温度≥600°C时，钠贝得石开始脱羟基，在600°-630 ° C范围内达到最大值。在1100°C下，剩余的固体重结晶为Al 6Si 2 O 13（莫来石）和SiO2（方石英）。
Na-beidellite, a member of the smectite group, was grown hydrothermally from a gel of composition 0.35Na2O·2.35Al2O3·7.3SiO2 in NaOH solutions at a pH between 7.5 and 13.5, a pressure of 1 kbar, and a temperature of 350°C. The synthetic Na-beidellite was characterized by means of scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, electron microprobe, inductively coupled plasma-atomic emission spectroscopy, and thermogravimetric analysis. The unit-cell parameters of the orthorhombic cell are: a = 5.18, b = 8.96, and c = 12.54 Å. The cation-exchange capacity was determined to be 70 meq/100 g. A maximum of 40 wt. % water was present and reversibly lost by heating to about 55°C. The loss of water caused a decrease of the basal spacing to 9.98 Å. At temperatures ≥600°C, the Na-beidellite started to dehydroxylate, reaching its maximum in the range 600°–630°C. At 1100°C the remaining solid recrystallized to Al6Si2O13 (mullite) and SiO2 (cristobalite).