有机酸活化钾长石的机制及其应用研究
发布时间：2018-08-19 06:23
【摘要】：钾长石等硅酸盐矿物是陶瓷生产的主要原料,由于硅酸盐矿物晶格中硅氧键键能大,需要很高的温度才能发生反应,带来资源浪费和环境污染。而水稻生长过程中大量吸硅的现象表明,低分子量有机酸对打断硅酸盐矿物晶体结构中的Si-O-Si键有一定效果,本文为了探究低分子量有机酸对硅酸盐矿物的活化机理,并为陶瓷低温烧成带来新思路,利用甲酸、草酸及二者的复合酸对硅酸盐矿物主要原料之一的钾长石进行活化,测试活化过程中长石矿物晶格中硅、铝的溶出量、溶出形式以及活化前后长石性质的变化,然后将活化长石引入陶瓷坯料,用来降低陶瓷烧成温度。另一方面,材料科学领域的量子化学计算正快速发展,高性能计算也给材料科学的研究带来新思路。本文利用量子化学软件包Gaussian模拟钾长石的简化结构(HO)3-Si-O-Si-(OH)3和[(HO)3-Al-O-Si-(OH)3]-与甲酸、草酸以及水的反应,利用过渡态理论探究有机酸活化硅酸盐矿物的机理。研究发现,草酸对硅酸盐矿物的活化效果远大于水,铝硅酸盐矿物中Al-O键比Si-O键更容易被破坏。根据反应活化能的大小,大致确定硅酸盐矿物的溶解机理:草酸电离出的H+首先将矿物晶格中的桥氧质子化;然后,草酸和桥氧质子化产物发生水解反应,使矿物晶格中Si-O键或Al-O键破坏。经阿伦尼乌斯方程计算,草酸使硅酸盐矿物晶格中Si-O键断裂的反应速率提高了3.09×1027倍,使铝硅酸盐矿物晶格中Al-O键断裂的反应速率提高了2.53×1012倍。经过复合酸活化后的钾长石中Si O2和Al2O3的含量均减少,颗粒粒径减小了71.4%,比表面积增加了97.5%,结晶度变差。另外,将复合酸活化钾长石作为原料引入陶瓷坯料,含量仅为3%时,在1275℃下烧成便能获得原坯料在1325℃下烧成时的显微结构和性能,使烧成温度降低50℃。
[Abstract]:Silicate minerals such as potassium feldspar are the main raw materials for ceramic production. Because of the large bond energy of silicon and oxygen in silicate mineral lattice, it needs a high temperature to react, resulting in waste of resources and environmental pollution. However, the phenomenon of large amount of silicon absorption during rice growth shows that low molecular weight organic acids can break the Si-O-Si bond in silicate mineral crystal structure. In order to explore the activation mechanism of low molecular weight organic acid on silicate minerals, The potassium feldspar, one of the main raw materials of silicate minerals, was activated by formic acid, oxalic acid and their complex acids. The dissolution of Si and Al in the crystal lattice of feldspar minerals during activation was measured. The form of dissolution and the change of feldspar properties before and after activation, and then the activated feldspar was introduced into the ceramic blank to reduce the sintering temperature of ceramics. On the other hand, quantum chemistry calculation is developing rapidly in the field of material science. In this paper, the simplified structure of potassium feldspar, (HO) _ 3-Si-O-Si-( OH) _ 3 and [(HO) _ 3-Al-O-Si- (OH) _ 3] -reacts with formic acid, oxalic acid and water are simulated by quantum chemical software package Gaussian. The mechanism of activation of silicate minerals by organic acids is explored by means of transition state theory. It is found that oxalic acid can activate silicate minerals more effectively than water, and the Al-O bond in aluminosilicate minerals is easier to be destroyed than that of Si-O bonds. According to the activation energy of the reaction, the dissolution mechanism of silicate minerals is roughly determined: h ionization of oxalic acid first protonates the bridging oxygen in the mineral lattice, and then hydrolyzes oxalic acid and bridged oxygen protonation products. The Si-O bond or Al-O bond in the mineral lattice is destroyed. Calculated by Arrhenius equation, oxalic acid increases the reaction rate of Si-O bond fracture in silicate mineral lattice by 3.09 脳 1027 times, and the rate of Al-O bond fracture in aluminosilicate mineral lattice increases by 2.53 脳 1012 times. The contents of Sio _ 2 and Al2O3 in the potassium feldspar activated by complex acid decreased, the particle size decreased by 71.4, the specific surface area increased by 97.5 and the crystallinity became worse. In addition, when the composite acid-activated potassium feldspar is introduced into the ceramic blank, the microstructure and properties of the raw material can be obtained by sintering at 1275 鈩，
本文编号：2190923
[Abstract]:Silicate minerals such as potassium feldspar are the main raw materials for ceramic production. Because of the large bond energy of silicon and oxygen in silicate mineral lattice, it needs a high temperature to react, resulting in waste of resources and environmental pollution. However, the phenomenon of large amount of silicon absorption during rice growth shows that low molecular weight organic acids can break the Si-O-Si bond in silicate mineral crystal structure. In order to explore the activation mechanism of low molecular weight organic acid on silicate minerals, The potassium feldspar, one of the main raw materials of silicate minerals, was activated by formic acid, oxalic acid and their complex acids. The dissolution of Si and Al in the crystal lattice of feldspar minerals during activation was measured. The form of dissolution and the change of feldspar properties before and after activation, and then the activated feldspar was introduced into the ceramic blank to reduce the sintering temperature of ceramics. On the other hand, quantum chemistry calculation is developing rapidly in the field of material science. In this paper, the simplified structure of potassium feldspar, (HO) _ 3-Si-O-Si-( OH) _ 3 and [(HO) _ 3-Al-O-Si- (OH) _ 3] -reacts with formic acid, oxalic acid and water are simulated by quantum chemical software package Gaussian. The mechanism of activation of silicate minerals by organic acids is explored by means of transition state theory. It is found that oxalic acid can activate silicate minerals more effectively than water, and the Al-O bond in aluminosilicate minerals is easier to be destroyed than that of Si-O bonds. According to the activation energy of the reaction, the dissolution mechanism of silicate minerals is roughly determined: h ionization of oxalic acid first protonates the bridging oxygen in the mineral lattice, and then hydrolyzes oxalic acid and bridged oxygen protonation products. The Si-O bond or Al-O bond in the mineral lattice is destroyed. Calculated by Arrhenius equation, oxalic acid increases the reaction rate of Si-O bond fracture in silicate mineral lattice by 3.09 脳 1027 times, and the rate of Al-O bond fracture in aluminosilicate mineral lattice increases by 2.53 脳 1012 times. The contents of Sio _ 2 and Al2O3 in the potassium feldspar activated by complex acid decreased, the particle size decreased by 71.4, the specific surface area increased by 97.5 and the crystallinity became worse. In addition, when the composite acid-activated potassium feldspar is introduced into the ceramic blank, the microstructure and properties of the raw material can be obtained by sintering at 1275 鈩，
本文编号：2190923
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