(1. 中南大学 化学化工学院，长沙 410083；
2. 中南大学 相图及材料设计与制造中心，长沙 410083)
摘 要: 采用Pitzer-Simonson-Clegg模型对四元体系NaNO3-LiNO3-KNO3-H2O在273~358 K的溶解度相图进行预测，模型参数拟合于二元体系NaNO3-H2O、LiNO3-H2O、KNO3-H2O和三元体系NaNO3-LiNO3-H2O、NaNO3-KNO3-H2O、LiNO3-KNO3-H2O的水活度、渗透系数及溶解度数据，发现一个四元共晶点，该点组成为5.9% NaNO3、76.2% LiNO3·3H2O和17.9% KNO3(质量分数)，相变温度为295.6 K。通过吸放热行为测试及DSC检测对共晶点组成材料的储热性能进行研究。结果表明：该材料在相变温度附近具有良好的储放热性能，且热焓很大，可作为潜在的室温相变储能材料。
关键字: NaNO3；LiNO3；KNO3；Pitzer-Simonson-Clegg 模型；相变储能材料；相图
（1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. Science Center for Phase Diagram and Materials Design and Manufacture,
Central South University, Changsha 410083, China）
Abstract:A Pitzer-Simonson-Clegg model was applied to the predict phase diagram of the quaternary system NaNO3-LiNO3-KNO3-H2O from 273 K to 358 K, and the model parameters were fitted to the experimental water activity, osmotic coefficient and solubility of the binary systems NaNO3-H2O, LiNO3-H2O, KNO3-H2O and the ternary systems NaNO3-LiNO3-H2O, NaNO3-KNO3-H2O, LiNO3-KNO3-H2O. A quaternary eutectic point consisting of 5.9% NaNO3, 76.2% LiNO3·3H2O and 17.9% KNO3 was predicted, and the melting temperature is 295.6 K. The exothermal and endothermal behaviors of the predicted phase change material were measured and its DSC measurement was carried out. The experimental results show that the predicted material with larger melting heat has excellent heat storage and release ability, and it is expected to be used as the room temperature phase change material.
Key words: NaNO3; LiNO3; KNO3; Pitzer-Simonson-Clegg model; phase change material; phase diagram
