Secondary Nucleation of Various Types of Crystal in Different Solvents
Date Issued
2001
Date
2001
Author(s)
戴怡德
DOI
892214E002042
Abstract
In this study, the secondary nucleation of potassium
alum, citric acid and calcium carbonate crystals in the
aqueous and alcohol solutions was investigated. In the
potassium alum system the water jet was used to induce secondary nucleation by fluid shear. The results show
that the number of nuclei formed by secondary
nucleation decreases by increasing the time interval
between stopping the agitation and injecting the solution.
The decrease in number of nuclei can be interpreted by
the lower interfacial supersaturation at the longer
stop-agitated time. On the other hand, the citric acid
nuclei prepared in the propanol are very fine as powders
and the growth rate of nuclei is also small.
Consequently we are attempting to utilize other organic
solvents to prepare the seeds for the fluid-sheared
experiment. Finally the catastrophic secondary
nucleation of calcium carbonate is observed in this study.
Further, the induction period of calcium carbonate is
calculated by the coagulation theory, in which the cluster
concentration near the interface is taken into account. The results indicate that the interfacial supersaturation
plays a significant role in the formation of secondary
nuclei not only in the potassium alum but also in the
calcium carbonate system.
Subjects
介面過飽和度
次成核
鉀明礬
檸檬酸
碳酸鈣
Publisher
臺北市：國立臺灣大學化學工程學系暨研究所
Type
report
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