Crystal-size control and characterization ofNa-4-mica prepared from kaolinite
Crystal-size control and characterization ofNa-4-mica prepared from kaolinite
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高岭石制备Na-4-云母的晶体尺寸控制及表征
DOI：
10.1039/b009418h
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发表时间：
2001
影响因子：
--
通讯作者：
H. Schneider
中科院分区：
文献类型：
--
作者：
T. Kodama;Y. Harada;Masahito Ueda;Ken;K. Shuto;S. Komarneni;W. Hoffbauer;H. Schneider
一种简单经济的高电荷密度合成方法
本文研究了高岭石中Na-4-云母（理想化学组成为Na 4 Mg 6Al 4Si 4 O20 F4·xH 2 O）。合成条件
以控制晶体大小。合成了一种新型的膨润云母钠
由高岭石、硝酸镁（或超细MgO）
和NaF在850 °C下进行，并通过粉末X射线衍射（XRD）进行表征，
扫描电子显微镜（SEM），激光粒度分析
27 Al和29 Si魔角自旋核
磁共振（MAS-NMR）光谱。减少的质量
Na-4-云母晶化过程中的NaF助熔剂使微晶尺寸减小
从2到0.2 μm。随着微晶尺寸的减小，
云母的粒径从5 μ m减小到2 μm。27Al
MAS-NMR谱表明，Al以四面体配位
而~（29）Si MAS-NMR谱表明，
Si的环境主要在Si（3Al）中，正如基于
硅铝比
A simple and economical method for the synthesis of high-charge-density
Na-4-mica (ideal chemical composition of Na4Mg6Al4Si4O20F4·xH2O) from kaolinite was investigated. Synthesis conditions
were varied to control crystal size. This novel swelling Na-4-mica was synthesized
from a mixture of kaolinite, magnesium nitrate (or ultrafine MgO)
and NaF at 850 °C, and characterized by powder X-ray diffraction (XRD),
scanning electron microscopy (SEM), particle size analysis by laser
diffraction and 27Al and 29Si magic angle spinning nuclear
magnetic resonance (MAS-NMR) spectroscopy. Decreasing the mass of
NaF flux during the crystallization of Na-4-mica reduced the crystallite size
from 2 to 0.2 µm. As the crystallite size decreased, the average
particle size of the mica decreased from 5 to 2 µm. 27Al
MAS-NMR spectra showed that all or nearly all Al is in tetrahedral coordination
whereas 29Si MAS-NMR spectra showed that the nearest neighbour
environment of Si is mainly in Si(3Al), as expected based on the
Si∶Al ratio.