Dehydration Process and Mechanism of Magnesium Nitrate Hexahydrate Using Thermal Analysis Technique

被引:0
作者
Zhong Y. [1 ,2 ,3 ]
Wang M. [2 ,3 ]
Yuan J. [1 ]
机构
[1] School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin
[2] Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining
[3] Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Xining
来源
Cailiao Daobao/Materials Reports | 2020年 / 34卷 / 22期
基金
中国国家自然科学基金;
关键词
Dehydration; Magnesium nitrate hexahydrate; Thermal analysis; Thermodynamic calculation;
D O I
10.11896/cldb.19120063
中图分类号
学科分类号
摘要
Magnesium nitrate-based molten salt has a wide application prospect as a medium temperature energy storage material forsolar thermal po-wer generation. The research on the dehydration process and mechanism of magnesium nitrate hexahydrate is of guiding significance for the preparation of magnesium nitrate. The dehydration process and mechanism of magnesium nitrate hexahydrate were studied in this work through simultaneously TG/DSC. The thermodynamic functions of dehydration reaction of magnesium nitrate hexahydrate were calculated. The dehydration products were characterized by XRD, Raman and DSC. The results of calculation show that magnesium nitrate hexahydrate is dehydrated to magnesium nitrate when the temperature is above 168.02℃ in standard state. In the process of program heating, first magnesium nitrate hexahydrate is melted to a solution, then magnesium nitrate dihydrate precipitates from the solution as the water loses. This dehydration process can be described according to the phase equilibrium of magnesium nitrate-water solution. Solid magnesium nitrate dihydrate is melted at 130℃. The melt is dehydrated to anhydrous magnesium nitrate, which involves a liquid-solid heterogeneous phase reaction. The melt is completely dehydrated to anhydrous magnesium nitrate at higher temperature than the calculated value, indicating that this dehydration reaction is thermodynamically spontaneous. © 2020, Materials Review Magazine. All right reserved.
引用
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页码:22015 / 22019
页数:4
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