Dehydration kinetics of muscovite by in situ infrared microspectroscopy
Dehydration kinetics of muscovite by in situ infrared microspectroscopy
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DOI：
10.1007/s00269-009-0313-3
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发表时间：
2010-02-01
影响因子：
1.4
通讯作者：
Nakashima, Satoru
中科院分区：
文献类型：
--
作者：
Tokiwai, Kazuyo;Nakashima, Satoru
用原位高温显微红外光谱法研究了白云母片在760- 860 ℃的脱水行为。在每个温度下的等温动力学加热实验给出了详细的OH带面积随时间的减少曲线。这些曲线已被模拟的一级和二级反应或单，二维扩散过程。在760- 860 ℃范围内，用一维扩散模型拟合实验数据，求得表观扩散系数D，活化能为290 +/-A20 kJ/mol。表观扩散系数D随样品厚度L的变化而变化。这种变化可以通过具有恒定扩散系数D '的单位长度L'的m层模型来解释。因此，脱水过程可能是通过垂直于白云母（001）面的四面体硅酸盐片（单位长度为L '）的一维扩散速率限制的。
Dehydration behavior of muscovite flake was investigated at 760-860A degrees C by using in situ high-temperature IR microspectroscopy for the OH absorption band around 3,620 cm(-1). Isothermal kinetic heating experiments at each temperature gave detailed decrease curves of the OH band area with time. These curves have been simulated by the first and second order reactions or mono- and two-dimensional diffusion processes. The mono-dimensional diffusion was found to give the best fit to the experimental data and apparent diffusion coefficients D were determined at 760-860A degrees C with the activation energy of 290 +/- A 20 kJ/mol. The apparent diffusion coefficients D varied with the sample thickness L. This variation can be explained by an m layers model with a unit length of L' with a constant diffusion coefficient D'. Therefore, the dehydration process might be rate-limited by mono-dimensional diffusion through tetrahedral silicate sheet perpendicular to (001) planes of muscovite with a unit length of L'.