(1. 中南大學(xué) 化學(xué)化工學(xué)院，長沙 410083；
2. 中南大學(xué) 相圖及材料設(shè)計與制造中心，長沙 410083)
摘 要: 采用Pitzer-Simonson-Clegg模型對四元體系NaNO3-LiNO3-KNO3-H2O在273~358 K的溶解度相圖進(jìn)行預(yù)測，模型參數(shù)擬合于二元體系NaNO3-H2O、LiNO3-H2O、KNO3-H2O和三元體系NaNO3-LiNO3-H2O、NaNO3-KNO3-H2O、LiNO3-KNO3-H2O的水活度、滲透系數(shù)及溶解度數(shù)據(jù)，發(fā)現(xiàn)一個四元共晶點，該點組成為5.9% NaNO3、76.2% LiNO3·3H2O和17.9% KNO3(質(zhì)量分?jǐn)?shù))，相變溫度為295.6 K。通過吸放熱行為測試及DSC檢測對共晶點組成材料的儲熱性能進(jìn)行研究。結(jié)果表明：該材料在相變溫度附近具有良好的儲放熱性能，且熱焓很大，可作為潛在的室溫相變儲能材料。
關(guān)鍵字: NaNO3；LiNO3；KNO3；Pitzer-Simonson-Clegg 模型；相變儲能材料；相圖
（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
