【摘要】：以硝酸鉀水溶液為研究對象,考察了雜質(zhì)離子對共晶冷凍結(jié)晶過程中冰晶結(jié)晶特性的影響。首先,建立并驗證了共晶冷凍結(jié)晶過程冰點的測定方法,并基于Extend-UNIQUAN模型對硝酸鉀體系的冰點進行模擬計算。同時考察了不同種類雜質(zhì)離子對硝酸鉀水溶液冰點、結(jié)晶點、以及冷凍介穩(wěn)區(qū)寬度的影響,實驗研究結(jié)果表明:硝酸鉀水溶液中離子雜質(zhì)濃度越高,冰點、結(jié)晶點的溫度越低,介穩(wěn)區(qū)寬度越寬;雜質(zhì)離子濃度相同的硝酸鉀水溶液其冰點溫度隨著雜質(zhì)離子半徑減小而減小,結(jié)晶點溫度和介穩(wěn)區(qū)寬度與陽離子雜質(zhì)價態(tài)成反比,與陰離子雜質(zhì)價態(tài)成正比。并利用基于經(jīng)典成核理論所推導(dǎo)的介穩(wěn)區(qū)寬度模型方程對實驗數(shù)據(jù)進行模擬計算,模擬結(jié)果與實驗值符合較好,計算得到硝酸鉀水溶液的冰晶成核級數(shù)為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.
【作者單位】： 天津科技大學(xué)化工與材料學(xué)院;邁安德集團有限公司;
【基金】：天津市應(yīng)用基礎(chǔ)與前沿技術(shù)研究計劃(重點項目)(14JCZDJC40900)
【分類號】：TQ131.13

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