微纳米碳酸钙粉体的制备及晶型与形貌的调控

发布时间：2018-06-17 06:39

本文选题：微纳米CaCO_3 + 表面活性剂　；参考：《湖北工业大学》2015年硕士论文

【摘要】：随着碳酸钙(CaCO_3)粉体应用的不断推广,对CaCO_3晶型和形貌的调控成为一个热门课题。本论文利用多种模板调控CaCO_3晶体的生长,考察了碳化工艺中影响晶体结晶状态和形貌的因素,对CaCO_3晶体的形成机理进行了研究,并对Ca(HCO_3)_2热分解法制备CaCO_3进行了初步探索。论文首先以棕榈酸为表面活性剂,研究了不同添加量的棕榈酸对Ca(OH)_2碳化生成的CaCO_3晶型与形貌的影响,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、激光粒度分析仪(ZPA)和傅里叶红外光谱仪(FT-IR)对CaCO_3的晶型和形貌进行了分析和观察,得出了添加棕榈酸不能改变CaCO_3的晶型,但可以影响CaCO_3形貌的结论,同时讨论了不同形貌CaCO_3颗粒的形成机制。论文接着在相同的实验条件下,研究了月桂酸、棕榈酸和硬脂酸等不同碳链长度的长链脂肪酸对CaCO_3晶型和形貌的调控。研究结果显示脂肪酸的加入对CaCO_3晶型同样没有影响,但是随着脂肪酸碳链长度和加入量的增加,CaCO_3颗粒更容易团聚成棒状的聚集体,聚集体体积也有变大的趋势。论文从不同碳链长度的脂肪酸在颗粒表面形成胶束的不同变形程度及其在不同加入量时的不同聚集状态讨论了不同形貌CaCO_3的形成机理。论文最后对Ca(HCO_3)_2热分解工艺制备CaCO_3进行了初步探索,在前期研究的基础上,着重考察了搅拌强度对Ca(HCO_3)_2热分解生成CaCO_3的影响,采用XRD和扫描电子显微镜(SEM)对CaCO_3的晶型和形貌晶型了分析和观察。结果发现搅拌强度不仅可以影响CaCO_3的颗粒形貌,还改变了CaCO_3的晶体类型,即搅拌限制了热力学最不稳定相球霰石的结晶,而有利于稳定的方解石相的结晶。当PEG-6000添加到反应体系中时,随着搅拌的加强,也得出了类似的结果。论文从原子堆积角度解释了搅拌对CaCO_3晶型的影响。论文成功地以Ca(OH)_2为原料、以碳化法制备微纳米CaCO_3,对合成过程中CaCO_3的晶型、形貌以及形成机理进行了研究和分析,为不同形貌CaCO_3粉体的调控制备提供了理论依据。特别地,对Ca(HCO_3)_2热分解工艺制备CaCO_3进行的初步探索也为CaCO_3粉体的制备提供了一个全新的途径,并为该工艺中不同晶型和形貌CaCO_3粉体的调控提供了理论依据。
[Abstract]:With the increasing application of CaCO3) powder, the regulation of CaCOS3 crystal form and morphology has become a hot topic. In this paper, the growth of CaCOs _ 3 crystal is regulated by various templates. The factors affecting the crystal state and morphology in carbonization process are investigated. The formation mechanism of CaCO-C _ 3 crystal is studied, and the preparation of CaCOS _ 3 by thermal decomposition method is studied. In this paper, palmitic acid was first used as surfactant to study the effect of palmitic acid on the morphology and morphology of CaCOS3 formed by carbonization of CaOH-2. The crystal structure and morphology of CaCO3 were analyzed and observed by X-ray diffractometer, scanning electron microscope (SEM), transmission electron microscope (TEM), laser particle size analyzer (ZPA) and Fourier transform infrared spectroscopy (FTIR). The results show that palmitic acid can not change the crystal form of CaCO3. The formation mechanism of CaCO3 particles with different morphology was discussed. Under the same experimental conditions, the effects of long chain fatty acids such as lauric acid, palmitic acid and stearic acid on the crystal form and morphology of CaCO3 were studied. The results showed that the addition of fatty acids had no effect on the crystal form of CaCOC _ 3, but with the increase of carbon chain length and addition amount of fatty acids, CaCOC _ 3 particles were more easily agglomerated into rod-like aggregates, and the aggregate volume also tended to increase. In this paper, the formation mechanism of CaCO3 with different morphology was discussed from the different deformation degree of fatty acids with different carbon chain length on the surface of particles and the different aggregation states of different amount of fatty acids added. At the end of the paper, the preparation of Caco _ 3 by the thermal decomposition process of Caco _ 3S _ 2 was studied. On the basis of the previous research, the influence of stirring intensity on the thermal decomposition of CaHCO-3T _ 2 to CaCO-S _ 3 was investigated. The crystal and morphology of CaCO3 were analyzed and observed by XRD and SEM. The results show that stirring intensity can not only affect the morphology of CaCOS3, but also change the crystal type of CaCO3, that is, agitation limits the crystallization of the most unstable phase in thermodynamics, but is beneficial to the crystallization of stable calcite phase. When PEG-6000 was added to the reaction system, a similar result was obtained with the agitation. In this paper, the effect of agitation on the crystal form of CaCO3 is explained from the angle of atomic stacking. In this paper, CaCO3 was successfully prepared by carbonization method from CaOH _ 2. The crystal form, morphology and formation mechanism of CaCO-C _ 3 in the process of synthesis were studied and analyzed, which provided a theoretical basis for the preparation of CaCO3 powders with different morphologies. In particular, the preliminary exploration on the preparation of CaCO3 by the thermal decomposition process of CaHCO3 / s _ 2 also provides a new way for the preparation of CaCO3 powder, and provides a theoretical basis for the regulation of CaCO3 powders with different crystal forms and morphology.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.32;TB383.1

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