杂质SO_4^(2-)对混合硝酸盐结构影响分析  

Influence of SO_4^(2-) on the structure of mixed nitrate salts

作　　者：倪海欧 孙泽[1] 黄龙 周扬 庞旭岩 宋兴福[1] 于建国[1] 

机构地区：[1]华东理工大学国家盐湖资源综合利用工程技术研究中心,上海200237 [2]青海盐湖工业股份有限公司化工分公司,青海格尔木816000

出　　处：《储能科学与技术》2016年第2期210-214,共5页Energy Storage Science and Technology

基　　金：国家自然科学基金项目(U1407126)

摘　　要：随着能源技术的发展,硝酸盐作为储能介质的应用越来越广泛,但是有关熔盐结构的研究偏少,特别是杂质离子对混合盐结构和性质的影响,鲜有文献报道。然而,杂质离子却会对混合熔盐的宏观热物性、腐蚀性等产生不同程度的影响,不可忽略,对其微观结构的研究或对宏观性质的研究有所帮助。本文以质量比为1∶1的KNO_3/NaNO_3混合盐为基础,向其中添加SO_4^(2-)离子。测量了含杂质混合盐在不同温度的拉曼光谱和高温XRD图谱,考察了SO_4^(2-)离子对硝酸盐混合物结构的影响。结果表明,在熔盐冷凝结晶时SO_4^(2-)会优先与Na+结合,并且在常温下SO_4^(2-)以固溶体的形式存在。不同温度下的谱图表明,在200℃时混合盐的结构和常温下相比有显著的改变,发生了固-固相变生成新相,且SO_4^(2-)固溶状态被打破。Recent developments in energy technologies have led to an increased effort in scientific research into the use of nitrate salts as an energy storage material in recnet years. However, little is known about on the structure of molten salts and the influence of impurities on the structure of molten salt mixtures have been seldom reported. The presence of impurities can impose impacts on the thermophysical characteristics of molten salts that cannot be neglected. This study examines the addition of SO_4^（2-） on the structure and hence properties of a mixed KNO_3/NaNO_3 salt with mass ratio of 1∶1 a Raman spectral meter and a X-ray diffractometer were used in the measurements under different temperatures. The results suggests that when the molten salt solidifies and crystallizes, SO_4^（2-）ions combine with Na＋ preferentially, and Na＋ ions exist in the form of solid solution. It was also found that SO_4^（2-） ions exist in the form of solid solution at the room temperature, and the structure of the mixed salts change significantly at 200 ℃ compared to that at room temperature, suggesting a solid-solid phase change during the heating procedure. The results also show that the state of solid solution of SO_4^（2-） breaks at about 200 ℃.

关 键 词：熔盐结构 杂质离子 高温拉曼光谱 高温X射线衍射 

分 类 号：TQ131.1[化学工程—无机化工]