纳米碳酸钙制备新工艺研究

发布时间：2018-02-11 05:19

本文关键词： 纳米碳酸钙常温碳化高浓度CO_2 压滤水循环节能降耗　出处：《华东理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米碳酸钙作为一种功能性填料广泛应用于多种行业,同时它也是一个能耗较高的产业,在坚持走可持续发展道路的今天,碳酸钙的生产不仅要追求产品的优越性能,同时也要关注生产过程的低能耗,如何提高产品的应用性能和减少生产过程的能耗一直是纳米碳酸钙应用技术研究的热点,这不仅是碳酸钙生产工艺的发展方向,而且也是提高碳酸钙产业经济效益的重要手段。本文采用常温碳化技术合成立方形纳米碳酸钙,研究了晶体成核、生长过程晶型控制剂在纳米碳酸钙表面的吸附情况及其对纳米碳酸钙形貌控制的机理,探讨了碳化反应工艺条件对纳米碳酸钙晶体成核、生长、凝并和最终形貌的影响,重点考察温度、高浓度C02气体作为气源对纳米碳酸钙形貌的控制作用；改进常温碳化工艺,合成分散性好的纳米碳酸钙粉体,并对粉体的应用性能进行表征；研究了工艺压滤水循环利用的可行性,为纳米碳酸钙工业生产节能技术提供了技术的支持。晶型控制剂吸附在碳酸钙表面控制其形貌为立方形,碳化反应温度通过改变晶型控制剂在活性碳酸钙表面吸附率来改变形貌。温度升高,吸附率减小,生长快,凝并加剧,形貌不可控,增加晶型控制剂在体系中的浓度可以合成立方形纳米碳酸钙。常温时,高浓度CO2气体作为气源,传质效果不佳,凝并生长增强,纳米碳酸钙粒径分布不均匀,加强体系的搅拌强度,可以缓解粒度分布不均匀现象。改进常温碳化工艺合成了形貌规整、粒度分布均匀的立方形纳米碳酸钙,增加了粉体的分散性。对碳化新工艺进行工业试验,工业釜内传质效果稍差,但是纳米碳酸钙产品的各项性能指标均与小试一致,且其分散性等应用性能优于普通纳米碳酸钙。本文最后就压滤水循环利用的可行性进行研究,结果表明,纳米碳酸钙生产工艺的压滤水可循环利用,晶型控制剂的补充添加量按系统中晶型控制剂的实际浓度计算较为合理。
[Abstract]:As a kind of functional filler, nanometer calcium carbonate is widely used in many industries, at the same time, it is also an industry with high energy consumption. In today's sustainable development, the production of calcium carbonate should not only pursue the superior performance of the products. At the same time, we should also pay attention to the low energy consumption in the production process. How to improve the application performance of the products and reduce the energy consumption in the production process has always been the focus of research on the application technology of nanometer calcium carbonate, which is not only the development direction of the production process of calcium carbonate, It is also an important means to improve the economic benefit of calcium carbonate industry. In this paper, square nanometer calcium carbonate was formed by normal temperature carbonization technique. The adsorption of crystal shape control agent on the surface of nanometer calcium carbonate and the mechanism of controlling the morphology of nanometer calcium carbonate were studied. The effects of carbonation conditions on the nucleation, growth, condensation and final morphology of nanocrystalline calcium carbonate were discussed. The effects of temperature, high concentration CO2 gas as gas source on the morphology of nanometer calcium carbonate were investigated, and the carbonation process at room temperature was improved. Nano-CaCO3 powders with good dispersity were synthesized and their application properties were characterized. The feasibility of water recycling by pressure-filtration was studied, which provided technical support for energy-saving technology of nano-CaCO3 production. The morphology of the crystal type control agent adsorbed on the surface of calcium carbonate is square. The temperature of carbonation reaction changes the morphology by changing the adsorption rate of the crystal type control agent on the surface of active calcium carbonate. The morphology is out of control, increasing the concentration of crystal type control agent in the system can make the square nanometer calcium carbonate. At room temperature, the high concentration of CO2 gas as the gas source, the effect of mass transfer is not good, the coagulation and growth are enhanced, and the particle size distribution of nanometer calcium carbonate is not uniform. Strengthening the agitation strength of the system can alleviate the uneven distribution of particle size. A square nanometer calcium carbonate with regular morphology and uniform particle size distribution was synthesized by improving the normal temperature carbonization process, and the dispersion of the powder was increased. The industrial test of the new carbonization process showed that the effect of mass transfer in the industrial kettle was slightly poor. However, the properties of nanometer calcium carbonate are consistent with those of small scale test, and its dispersity is superior to that of ordinary nanometer calcium carbonate. Finally, the feasibility of pressure filtration water recycling is studied. The results show that the pressure filter water produced by nanometer calcium carbonate can be recycled. The addition of crystal type control agent is reasonable according to the actual concentration of crystal type control agent in the system.
【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

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