Abstract：A method for the determination of solubility of aluminum in Na3AlF6-Al2O3 molten salt was studied. The sodium fluoride and sample
were melted at high temperature. The fusant was dissolved in water followed by adding H3BO3-NaOH solution. The Al2O3 was removed
by filtration and precipitation. At pH 5.5-6.0, the excessive EDTA standard solution was added into partial prepared solution.
The aluminum could be fully complexed with EDTA through boiling. The excessive EDTA was titrated with Zn2+ standard solution
using xylenol orange as indicator. Consequently, the content of Al3+ in Na3AlF6-Al2O3 molten salt could be obtained. Then, the
content of fluorine in another part of solution was measured by fluorine ion selective electrode to calculate the content of
aluminum ion in cryolite. Therefore, the dissolution amount of aluminum in Na3AlF6-Al2O3 system could be obtained by subtraction.
The value was important to production process and it could characterize the size of aluminum loss due to solution in electrolyte
molten salt.
