Stability of Sepiolite in Neutral and Alkaline Media at Room Temperature
Stability of Sepiolite in Neutral and Alkaline Media at Room Temperature
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DOI：
10.1180/claymin.1996.031.2.08
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发表时间：
1996-06
期刊：
影响因子：
1.5
通讯作者：
S. Martínez-Ramírez;F. Puertas;M. Blanco-Varela
中科院分区：
文献类型：
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作者：
S. Martínez-Ramírez;F. Puertas;M. Blanco-Varela
本文研究了产自西班牙Vallecas的一种西班牙海泡石在0.04NNaOH（pH = 12.6）、Ca（OH）2饱和溶液（pH = 12.6）和去离子/蒸馏水（pH = 7）中的化学和结构稳定性。通过测定动力学试验期间固体残留物中Mg、Si和Ca的浓度来评价化学稳定性。通过测定比表面积和“微晶”尺寸的变化来研究结构稳定性。通过BET法测定比表面积，通过X射线衍射线的轮廓测定“微晶”尺寸。主要结论是，海泡石是一种在中性和碱性介质中具有高化学稳定性的材料，没有明显的结构变化。然而，在碱性介质中，观察到比在中性介质中更大的二氧化硅溶解，二氧化硅来自于连接到OH-基团的最外部的四面体。
Abstract The chemical and structural stability of a Spanish sepiolite from Vallecas, Spain, was studied in 0.04 N NaOH (pH = 12.6), a saturated solution of Ca(OH)2 (pH = 12.6) and deionized/ distilled water (pH = 7). The chemical stability was evaluated by determining the concentrations of Mg, Si and Ca in the solid residues during the kinetic test. The structural stability was studied by determining the changes in specific surface area and 'crystallite' size. The specific surface was determined by the BET method and the 'crystallite' size by the profile of the X-ray diffraction line. The main conclusion was that sepiolite is a material with high chemical stability in neutral and alkaline media, with no significant structural changes. However, in alkaline media, greater dissolution of silica was observed than in neutral media, the silica being derived from the most external tetrahedra attached to the OH- groups.