三水碳酸镁晶体形貌调控研究

发布时间：2018-03-19 11:30

本文选题：三水碳酸镁晶体　切入点：晶型　出处：《辽宁工程技术大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,有关三水碳酸镁晶体的合成制备成为研究热点,对于三水碳酸镁晶体形貌调控已被众多研究者所证实。但目前的研究主要停留于棒状形貌晶体制备方面,对放射状三水碳酸镁的制备、外加场对晶体结晶形貌的调控作用以及二者的作用机理解释较少。论文旨在对放射状三水碳酸镁晶体和微波辅助合成棒状三水碳酸镁的制备过程进行研究,在不改变晶体物化性能的前提下,初步探索制备两种三水碳酸镁晶体有效合成方法,为晶体的深入研究及其潜在的低成本工业化生产提供一些试验参考数据。该研究结果不仅丰富了碳酸镁晶体形貌可控制备的理论和方法,对无机微纳米材料形貌可控制备及低成本、高性能精细镁盐工业化生产奠定科学基础,同时为构建微纳米材料知识框架提供理论依据。论文通过观察三水碳酸镁晶体在液相体系中的形貌演变过程,分析了其形貌及物相变化规律,在此基础上对放射状三水碳酸镁的形成过程和微波场辅助作用下三水碳酸镁晶体形貌的形成机理进行了探索研究。在放射状三水碳酸镁制备方面,论文考虑了反应物浓度、反应时间、反应温度对试验结果的影响,由试验可知,NH4HCO3的初始浓度是影响放射状晶体形成的关键,Mg2+的初始浓度主要控制晶体的生成量,反应时间与反应温度对放射状形貌影响不大。在微波辅助液相合成棒状三水碳酸镁方面,论文考虑了反应时间与微波辐照能量对试验结果的影响,经试验证明,当反应时间过长和微波辐照能量过高时都会导致棒状晶体结构坍塌,晶体物相由三水碳酸镁向四水合碱式碳酸镁转变。最后,论文通过试验现象的对比分别揭示了放射状碳酸镁晶体及微波辅助制备棒状碳酸镁晶体的形貌调控合成机理。论文的创新性主要体现在：制备出放射状三水碳酸镁,在三水碳酸镁晶体制备领域领域尚属首次；将微波场引入合成过程中,研究微波场在晶体结晶生长过程中的作用,在三水碳酸镁制备领域也鲜有报道；论文对二者的反应机理也做了研究,并对其形成机理进行了揭示,尤其是发现了镁铵络合离子,以及其在放射状三水碳酸镁晶体合成过程中起到的作用。
[Abstract]:At present, the synthesis and preparation of magnesium carbonate trihydrate crystal has become a hot topic, and the morphology regulation of magnesium carbonate trihydrate crystal has been confirmed by many researchers. Preparation of radioactive magnesium carbonate trihydrate, The effect of applied field on crystal morphology and the mechanism of their action are few. The purpose of this paper is to study the preparation process of radial magnesium carbonate trihydrate and microwave-assisted synthesis of rod magnesium trihydrate. Without changing the physical and chemical properties of the crystals, the effective synthesis methods of two kinds of magnesium carbonate trihydrate crystals were preliminarily explored. The results not only enrich the theory and method of controlled preparation of magnesium carbonate crystal morphology, but also provide some experimental reference data for the further study of the crystal and its potential low cost industrial production. It lays a scientific foundation for the controlled preparation of inorganic micro and nano materials and the industrial production of fine magnesium salts with low cost and high performance. At the same time, it provides the theoretical basis for constructing the knowledge frame of micro and nano materials. By observing the evolution process of the morphology of magnesium carbonate trihydrate in liquid phase system, the law of morphology and phase change of magnesium carbonate trihydrate crystal is analyzed. On this basis, the formation process of radial magnesium carbonate trihydrate and the formation mechanism of crystal morphology of magnesium carbonate trihydrate under the assistance of microwave field were studied. In the preparation of radial magnesium carbonate trihydrate, the concentration of reactant was considered. The effect of reaction time and reaction temperature on the experimental results shows that the initial concentration of NH _ 4HCO _ 3 is the key to the formation of radial crystals, and the initial concentration of Mg2 mainly controls the amount of crystal formation. The effect of reaction time and reaction temperature on the radial morphology was not significant. In the microwave assisted liquid phase synthesis of magnesium carbonate trihydrate, the effects of reaction time and microwave irradiation energy on the experimental results were considered. When the reaction time is too long and the microwave irradiation energy is too high, the rod-like crystal structure collapses and the crystal phase changes from magnesium carbonate trihydrate to basic magnesium carbonate tetrahydrate. In this paper, the morphology regulation and synthesis mechanism of radial magnesium carbonate crystal and microwave-assisted rod magnesium carbonate crystal are revealed by comparison of experimental phenomena. The main innovation of this paper is: preparation of radial magnesium carbonate trihydrate. It is the first time in the field of preparation of magnesium carbonate trihydrate, the effect of microwave field on crystal crystal growth is studied, and there are few reports in the field of preparation of magnesium carbonate trihydrate. In this paper, the reaction mechanism is also studied, and its formation mechanism is revealed, especially the magnesium ammonium complex ion and its role in the synthesis of radial magnesium carbonate crystals.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.2;O76

【参考文献】