NaF-AlF3-LiF熔盐结构的冰点降低法研究

Low-temperature aluminum electrolysis is an effective way to decrease the energy consumption of aluminum industry, and enrichment of lithium salts is one of the important technologies of low-temperature aluminum electrolysis. In the present study, molten structure of NaF-AlF3-LiF and the activity of related materials with different cryolite ratio(CR) and content of LiF was researched by cryoscopic method. The results have shown that there are also only two kinds of ion complexes existed in NaF-AlF3 melts after the addition of LiF, those are AlF63- and AlF4-, but the contents will be changed. The content of AlF63- and F- increases with the increase of CR, while that of AlF4- decreases. The content of AlF63- increases with the LiF contents, and that of AlF4- and F- decreases. For the melts with the same contents of LiF, the activity of NaAlF6，NaAlF4 and NaF has shown the same changing trend with CR as the mole fraction of the corresponding anion.