冷冻干燥法制备超细碳酸氢钠工艺研究
发布时间：2019-01-03 17:46
【摘要】： 本文采用冷冻干燥法,以制备高品质超细碳酸氢钠为目标,研究了冷冻干燥法制备超细碳酸氢钠的可行性及其工艺规律,并在此基础上开展了优化工艺参数、提高冻干效率的工艺探索。 本文通过三个重要步骤：前驱液体溶液制取、溶液冻结和冻结物冷冻干燥,得到了超细的碳酸氢钠粉体。采用XRD、激光粒度仪、SEM对所制粉体性能进行了分析和表征,结果表明采用冷冻干燥法所制得的粉体粒径小而均匀、粒度分布狭窄、粒子间团聚少、分散性好,且其晶化程度都有一定程度的降低。 在实验中采用了直接冷冻、真空蒸发冷冻和喷雾冷冻三种冷冻方式。喷雾冷冻得到的粉体粒径最小,为2.26um,其中喷射压力对碳酸氢钠粉体的粒径影响最大,溶液浓度次之。研究发现,高的冻结速率、低的前驱体溶液浓度有利于制备颗粒尺寸更为细小的粉体。 此外,本文研究了工艺条件对冷冻干燥效率的影响。研究结果表明,冻结速率越高、物料厚度越薄、物料升华面积越大则单次干燥越快,耗时越短,其中物料厚度对干燥速率的影响较为显著；在前驱体溶液中加入5%的叔丁醇可改变溶剂的结晶形态,有效加快干燥速率。
[Abstract]:In this paper, the freeze-drying method was used to prepare ultrafine sodium bicarbonate as the target. The feasibility and technological rules of preparing ultra-fine sodium bicarbonate by freeze-drying method were studied, and the technological parameters were optimized. Exploration of improving freeze-drying efficiency. In this paper, ultrafine sodium bicarbonate powder was obtained by three important steps: preparation of precursor liquid solution, freezing of solution and freeze-drying of frozen substance. The properties of the powders were analyzed and characterized by XRD, laser granularity analyzer and SEM. The results show that the powders prepared by freeze-drying method have small and uniform particle size, narrow particle size distribution, less agglomeration between particles and good dispersion. The degree of crystallization is decreased to some extent. Direct freezing, vacuum evaporation and spray freezing were used in the experiment. The particle size of the powder obtained by spray freezing is the smallest, which is 2.26 um.The spray pressure has the greatest influence on the particle size of sodium bicarbonate, followed by the concentration of solution. It was found that high freezing rate and low concentration of precursor solution were beneficial to the preparation of smaller powders. In addition, the effect of technological conditions on freeze-drying efficiency was studied. The results show that the higher the freezing rate, the thinner the material thickness, the bigger the material sublimation area, the faster the drying time is and the shorter the time is, and the more significant the effect of material thickness on drying rate is. The addition of 5% tert-butanol to the precursor solution can change the crystal morphology of the solvent and accelerate the drying rate effectively.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.3
本文编号：2399696
[Abstract]:In this paper, the freeze-drying method was used to prepare ultrafine sodium bicarbonate as the target. The feasibility and technological rules of preparing ultra-fine sodium bicarbonate by freeze-drying method were studied, and the technological parameters were optimized. Exploration of improving freeze-drying efficiency. In this paper, ultrafine sodium bicarbonate powder was obtained by three important steps: preparation of precursor liquid solution, freezing of solution and freeze-drying of frozen substance. The properties of the powders were analyzed and characterized by XRD, laser granularity analyzer and SEM. The results show that the powders prepared by freeze-drying method have small and uniform particle size, narrow particle size distribution, less agglomeration between particles and good dispersion. The degree of crystallization is decreased to some extent. Direct freezing, vacuum evaporation and spray freezing were used in the experiment. The particle size of the powder obtained by spray freezing is the smallest, which is 2.26 um.The spray pressure has the greatest influence on the particle size of sodium bicarbonate, followed by the concentration of solution. It was found that high freezing rate and low concentration of precursor solution were beneficial to the preparation of smaller powders. In addition, the effect of technological conditions on freeze-drying efficiency was studied. The results show that the higher the freezing rate, the thinner the material thickness, the bigger the material sublimation area, the faster the drying time is and the shorter the time is, and the more significant the effect of material thickness on drying rate is. The addition of 5% tert-butanol to the precursor solution can change the crystal morphology of the solvent and accelerate the drying rate effectively.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.3
【引证文献】
相关期刊论文 前1条
1 李菲;刘义;赵东风;林浩然;;反溶剂重结晶法制备超细碳酸氢钾粉体[J];现代化工;2012年04期
相关硕士学位论文 前1条
1 余红燕;冻干机控制系统的研究与设计[D];江西理工大学;2012年
，本文编号：2399696
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