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Magnesia formed on calcination of Mg(OH)(2) prepared from natural bischofite

机译：由天然重水铁矿制备的Mg（OH）（2）煅烧形成的氧化镁

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Calcination of magnesium hydroxide, which was prepared from natural bischofite MgCl(2)(.)6H(2)O, leading to dehydration 2(equivalent to MgOH) -> equivalent to Mg-O-Mg equivalent to + H2O, is accompanied by transition of phase not only to MgO but also to MgOx at x < I (assigned to Mg4O3) at moderate temperatures. At higher temperatures, MgOx, is completely transformed into MgO. Magnesium hydroxide and oxide heated at different temperatures were studied using the TEM, XRD, IR, PCs, TG-DTA, nitrogen and argon adsorption methods. The electronic structure of MgO and Mg4O3 was studied using the ab initio quantum chemical method with periodic conditions. According to TEM images, the morphology of particles changing from Mg(OH)(2) laminae to aggregates of interpenetrated MgO cubelets and foils depend strongly on the calcination temperature. Significant changes in surface area are observed mainly at 325-470 degrees C on desorption of a major portion of eliminated water corresponding to 28.4 wt.% at its total amount of 30.9 wt.%. Pore size distribution (PSD) is sensitive to treatment conditions and the main PSD peaks shift towards larger pore size with elevating temperature. The characteristics of the surface hydroxyls as well as of the bulk Mg-O bonds depend on heating conditions, as noticeable changes are observed in the XRD patterns and the IR spectra of the samples undergoing the mentioned transformation of phase Mg(OH)(2) -> MgOx - MgO. (c) 2005 Elsevier B.V. All rights reserved.
机译：伴随着氢氧化钙的煅烧，氢氧化钙是由天然的锂辉石MgCl（2）（。）6H（2）O制备的，导致脱水2（相当于MgOH）->相当于Mg-O-Mg相当于+ H2O在中等温度下，x≤I时相不仅转变成MgO，而且转变成MgOx（分配给Mg4O3）。在更高的温度下，MgOx完全转化为MgO。使用TEM，XRD，IR，PCs，TG-DTA，氮气和氩气吸附方法研究了在不同温度下加热的氢氧化镁和氧化物。利用周期性从头算量子化学方法研究了MgO和Mg4O3的电子结构。根据TEM图像，颗粒的形态从Mg（OH）（2）薄片变为互穿的MgO立方体和箔的聚集体，在很大程度上取决于煅烧温度。主要在325-470℃下观察到表面积的显着变化，这是由于除去水的大部分相当于其总含量30.9重量％的28.4重量％。孔尺寸分布（PSD）对处理条件敏感，并且随着温度的升高，主要PSD峰向更大的孔尺寸偏移。表面羟基以及Mg-O主体键的特性取决于加热条件，因为XRD图谱和经历了上述Mg（OH）（2）相转变的样品的IR光谱都观察到了显着变化-> MgOx-MgO。 （c）2005 Elsevier B.V.保留所有权利。

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