杂质离子对共晶冷冻结晶过程中冰晶结晶特性的影响
发布时间：2018-07-15 10:59
【摘要】：以硝酸钾水溶液为研究对象,考察了杂质离子对共晶冷冻结晶过程中冰晶结晶特性的影响。首先,建立并验证了共晶冷冻结晶过程冰点的测定方法,并基于Extend-UNIQUAN模型对硝酸钾体系的冰点进行模拟计算。同时考察了不同种类杂质离子对硝酸钾水溶液冰点、结晶点、以及冷冻介稳区宽度的影响,实验研究结果表明:硝酸钾水溶液中离子杂质浓度越高,冰点、结晶点的温度越低,介稳区宽度越宽;杂质离子浓度相同的硝酸钾水溶液其冰点温度随着杂质离子半径减小而减小,结晶点温度和介稳区宽度与阳离子杂质价态成反比,与阴离子杂质价态成正比。并利用基于经典成核理论所推导的介稳区宽度模型方程对实验数据进行模拟计算,模拟结果与实验值符合较好,计算得到硝酸钾水溶液的冰晶成核级数为1.46。
[Abstract]:The effect of impurity ions on the crystallization characteristics of ice crystals during eutectic freezing crystallization was investigated with potassium nitrate aqueous solution as the research object. Firstly, the method of freezing point measurement in eutectic freezing crystallization process was established and verified, and the freezing point of potassium nitrate system was simulated based on Extend-UNIQUAN model. The effects of different kinds of impurity ions on the freezing point, crystallization point and the width of freezing metastable zone of potassium nitrate aqueous solution were also investigated. The experimental results showed that the higher the concentration of ion impurity in potassium nitrate solution, the lower the temperature of crystallization point. The wider the metastable zone is, the smaller the freezing point temperature of potassium nitrate aqueous solution with the same impurity ion concentration decreases with the decrease of impurity ion radius. The crystallization point temperature and the metastable zone width are inversely proportional to the valence state of cationic impurity and are directly proportional to the valence state of anionic impurity. The experimental data are simulated by using the metastable zone width model equation derived from the classical nucleation theory. The simulation results are in good agreement with the experimental data, and the nucleation order of ice crystals in potassium nitrate aqueous solution is calculated to be 1.46.
【作者单位】： 天津科技大学化工与材料学院;迈安德集团有限公司;
【基金】：天津市应用基础与前沿技术研究计划(重点项目)(14JCZDJC40900)
【分类号】：TQ131.13
本文编号：2123845
[Abstract]:The effect of impurity ions on the crystallization characteristics of ice crystals during eutectic freezing crystallization was investigated with potassium nitrate aqueous solution as the research object. Firstly, the method of freezing point measurement in eutectic freezing crystallization process was established and verified, and the freezing point of potassium nitrate system was simulated based on Extend-UNIQUAN model. The effects of different kinds of impurity ions on the freezing point, crystallization point and the width of freezing metastable zone of potassium nitrate aqueous solution were also investigated. The experimental results showed that the higher the concentration of ion impurity in potassium nitrate solution, the lower the temperature of crystallization point. The wider the metastable zone is, the smaller the freezing point temperature of potassium nitrate aqueous solution with the same impurity ion concentration decreases with the decrease of impurity ion radius. The crystallization point temperature and the metastable zone width are inversely proportional to the valence state of cationic impurity and are directly proportional to the valence state of anionic impurity. The experimental data are simulated by using the metastable zone width model equation derived from the classical nucleation theory. The simulation results are in good agreement with the experimental data, and the nucleation order of ice crystals in potassium nitrate aqueous solution is calculated to be 1.46.
【作者单位】： 天津科技大学化工与材料学院;迈安德集团有限公司;
【基金】：天津市应用基础与前沿技术研究计划(重点项目)(14JCZDJC40900)
【分类号】：TQ131.13
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