KF-KCl体系相图测定和相图的热力学评估问题的探讨

Determination and Thermodynamic Assessment of Phase Diagram of KCl-KF System

用差热分析和目测法重新测量了KF KCl系相图 ,差热分析和极限斜率法计算都证明KF在KCl中有显著的有限固溶度。据此对前人所作的KF KCl系熔盐溶液的热力学函数计算结果作了修正。分子动力学计算也证明 :在KCl一侧KF KCl系熔盐混合为弱放热过程 ,而不是前人根据KF KCl系无固溶度的假定所算出的吸热过程。我们的计算结果与Kleppa的精密量热实验结果一致。

Using DTA and visual polythermic method,the phase diagram of KCl-KF system has been re-determined.Both DTA and limiting slope at the KCl end prove that KF has significant solid solubility in KCl.Based on these results,the formula for excess enthalpy of the liquid mixtures of KCl-KF system obtained by Sangster and Pelton(they assumed no significant solid solubility in this system)should be corrected.A new formula for the E H(1) of KCl-KF melts has been derived based on the calorimetrical measurement by Kleppa.And it has been found that the thermodynamic computation of the liquidus curves of the phase diagram of KCl-KF system are in good agreement with the our experimental results and the results of Plato.