Phase diagram prediction of systems Mn(NO3)2-
M(NO3)n-H2O(M=Ca, Mg and Li) with
modified BET-model
M(NO3)n-H2O(M=Ca, Mg and Li) with
modified BET-model
(1. College of Chemistry and Chemical Engineering, Hunan University,
Changsha 410082, China;
2. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences,
Guangzhou 510070, China)
Changsha 410082, China;
2. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences,
Guangzhou 510070, China)
Abstract: BET-model parameters for the binary system Mn(NO3)2-H2O were obtained by fitting experimental water activities at 298.15K. The values obtained in this work were compared to those fitted previously for the systems Ca(NO3)2-H2O and Zn(NO3)2-H2O, showing reasonable agreement. With the model parameters fitted at 298K, the vapor pressure of the saturated solution for the phases Mn(NO3)2•6H2O and Mn(NO3)2•4H2O were predicted and shows quite good agreement with the experimental values. The phase diagram of the Mn(NO3)2-H2O system reproduced by the BET model shows smaller deviation from the experimental data than that by the extended UNIQUAC model. The ternary phase diagrams of the systems Me(NO3)n-Mn(NO3)2-H2O(Me=Mg, Ca and Li) are predicted with the binary model parameter and compared with available experimental data. The predicted eutectic compositions were given as possible heat storage materials.
Key words: activity; thermodynamic model; solubility; manganous nitrate; heat storage materials