纳米碳酸钙的制备及性能研究

发布时间：2018-02-10 20:35

本文关键词： 纳米碳酸钙石灰石镁含量成核促进剂晶型调节剂　出处：《华东理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米碳酸钙有多种形貌,不同形貌的纳米碳酸钙制备工艺不同,应用性能也各不一样。但石灰石原料中的镁含量,碳化和陈化体系中的Ca2+、CO32-等离子浓度对纳米碳酸钙的制备及性能有着重要的影响。本文以石灰石中的碳酸镁、成核促进剂和晶型调节剂为研究对象,通过考察体系中碳化反应速率、电导率、pH、离子浓度等参数,探究了其对碳酸钙成核、生长、凝并、熟化等过程的影响,从而探究了其对纳米碳酸钙制备及性能的影响。石灰石中的碳酸镁在碳化反应结束后主要以Mg2+形式存在液相中,活化后以碱式碳酸镁微晶颗粒的形式存在于粉体中。灰乳中的Mg2+在碳化反应前期促进碳酸钙的成核,而在碳化反应中期抑制碳酸钙晶体的生长。当灰乳中镁含量大于1.17%时,制备的纳米碳酸钙颗粒明显减小、链状颗粒增多,粉体的比表面积、吸油值、pH值以及饱和吸湿率均明显增大；当镁含量小于1.17%时,镁含量对纳米碳酸钙制备的影响较小。加入成核促进剂后,生成的碳酸钙晶种使得碳酸钙颗粒平均粒径增大、粒径分布变宽；随着陈化的进行,碳酸钙颗粒规整性变好,粒径显著增加,粒径分布变窄,至3h时,平均粒径约为120nm,粒径分布100-150 nm。加入晶型调节剂后,碳酸钙成核和生长速率增加,晶体生长时间延长,易形成大粒径、宽分布颗粒,但颗粒间凝并加剧、分散性变差；随着陈化的进行,碳酸钙颗粒粒径增大、规整性变好,陈化3h时粉体pH值约为8.2。
[Abstract]:Nano-calcium carbonate has many kinds of morphologies. The preparation process of nano-calcium carbonate with different morphology is different, and the application performance is different, but the content of magnesium in limestone raw material is different. The concentration of Ca2 CO32- in carbonation and aging system has an important effect on the preparation and properties of nano-calcium carbonate. In this paper, magnesium carbonate, nucleation accelerator and crystal type regulator in limestone are studied. The effects of carbonation reaction rate, conductivity pH and ion concentration on the nucleation, growth, coagulation and ripening of calcium carbonate were investigated. The effect of magnesium carbonate on the preparation and properties of nano-calcium carbonate was investigated. The magnesium carbonate in limestone was mainly deposited in liquid phase in the form of Mg2 after carbonization. The Mg2 in the gray milk promoted the nucleation of calcium carbonate in the early stage of carbonation, but inhibited the growth of the calcium carbonate crystal in the middle of the carbonization reaction. When the magnesium content in the grey milk was greater than 1.17, The prepared nano-calcium carbonate particles obviously decreased, chain particles increased, the specific surface area, oil absorption value, pH value and saturated moisture absorption rate increased obviously, and when the magnesium content was less than 1.17, The effect of magnesium content on the preparation of nanometer calcium carbonate is small. After adding nucleation accelerator, the average particle size of calcium carbonate particles increases and the particle size distribution becomes wider, and the regularity of calcium carbonate particles becomes better with aging. The particle size increased significantly and the particle size distribution became narrower. At 3 h, the average particle size was about 120 nm, and the particle size distribution was 100-150 nm. After adding crystal type regulator, the nucleation and growth rate of calcium carbonate increased, the crystal growth time was prolonged, and it was easy to form large particle size and wide distribution particle. With the aging, the particle size of calcium carbonate increased and the regularity became better. The pH value of the powder was about 8.2 when aged for 3 h.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ132.32;TB383.1

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