Alumina Solubility in Na3AlF6-K3AlF6-AlF3 Molten Salt System Prospective for Aluminum Electrolysis at Lower Temperature

作者：Li Jie; Yuan Chang-fu; Tian Zhong-liang^*; Wang Jia-wei; Lai Yan-qing; Liu Ye-xiang

来源：Chemical Research in Chinese Universities, 2012, 28(1): 142-146.

• Alumina solubility
• Lower temperature electrolyte
• Na3AlF6-K3AlF6-AlF3 molten salt system
• Aluminum electrolysis

The alumina solubility in the title system within the composition range of KR{m(K3AlF6)/[m(K3AlF6)+m(Na3AlF6)]) 10%-50%, a ternary Na3AlF6-K3AlF6-AlF3 molten system with 23%-29%(mass fraction) AlF3 was investigated by measuring the mass loss of a rotating sintered corundum disc. And the following empirical equation was derived when superheat degree was no more than 60 degrees C: w(Al2O3)(sat)=Ax(T/1000)(B), where A=-1.85774+26.754234w(AlF3)(-0.3683)-0.00783KR(2.363)+0.010266KR(2.3048) +0.7902w(AlF3)(0.00652), B=112.4625-53.2567w(AlF3)(0.4236)+5.1079w(AlF3)(09241)+0.01542w(AlF3)(1.3540). Considering both higher alumina solubility and not too high superheat degree are required, alumina solubility of different compositions at not the same temperature but the same superheat degree was studied, which will be more industrial helpful for selecting prospective compositions. The results show that the composition deserved to be further tested in lower temperature cells is 10%-30% KR and 23%-26%(mass fraction) AlF3.

• 出版日期2012-1-25
• 单位中南大学