## 4 Conclusions  
(1) Based on [PERSON]'s principle of measuring the ion migration number, a three-chamber cell is constructed in this study. Using the COMSO software, a flow field and electric field two-way coupling model is established to simulate electric field distributions in the anode, cathode, and middle electrode chambers. Under the action of the flow field in the electrolytic cell, the latter can be divided into three areas owing to the isolation effect of the baffle in the middle zone. The tank body consists of a well-defined cathode area, an anode area, and a transition area. The potentials of the cathode W rod and anode carbon rod remain unchanged, and the cell is considered to be an equipotential body. The electric field and current distributions vary on both electrode sides. The cathode and anode potentials near the intermediate transition isolation zone are stable, and there is a linear gradient along the vertical direction of the electrode. The intermediate transition zone exhibits a relatively high gradient, which satisfies the measurement requirements for the electromigration number.  
(2) In the AlF\({}_{3}\)-(Li,Na)F-Y\({}_{2}\)O\({}_{3}\) molten salt system, the migration number of Y(III) ions increases from 0.70 to 0.8 with an increase in temperature from 900 to 1000 \({}^{\circ}\)C, which  
Figure 5: Relationship between the cathode current density and the Y(III) ion mobility.  
represents an almost linear relationship. When the (Li,Na)F/AlF\({}_{3}\) molar ratio varies from 2.0 to 2.5, the migration number of Y(III) ions is relatively stable and equal to approximately 0.75. However, when the (Li,Na)F/AlF\({}_{3}\) molar ratio exceeds 2.5, the migration number of Y(III) ions decreases linearly from 0.75 to 0.45. In the current density range of 1.0-2.0 A/cm\({}^{2}\), the migration number of Y(III) ions increases from 0.65 to 0.85 almost linearly.  
(3) For AlF\({}_{3}\)-(Li,Na)F-Y\({}_{2}\)O\({}_{3}\) molten salt, the linear relationships between the Y(III) ion migration number and temperature, (Li,Na)F/AlF\({}_{3}\) molar ratio, and current density can be expressed by two different formulas: At (Li,Na)F/AlF\({}_{3}\) molar ratios of 2.1-2.5, \(n=0.572+1.05\times 10^{-4}\)T + 0.13I; however, when the (Li,Na)F/AlF\({}_{3}\) molar ratio exceeds 2.5, \(n=0.852+1.12\times 10^{-4}\)T - 0.22M + 1.15I.  
Conceptualization, X.W. and Y.Z.; methodology, X.W.; formal analysis, X.W. and T.H.; investigation, X.W. and T.H.; data curation, T.H.; writing--original draft preparation, T.H.; writing--review and editing, T.H.; supervision, Y.C.; project administration, X.W. All authors have read and agreed to the published version of the manuscript. This work was financially supported by the National Natural Science Foundation of China (No.51864018 and No.52074134) and the project of Jiangxi Provincial Department of Education (No. GJJ150666). The authors declare no conflict of interest.  
Not applicable. Data Availability StatementNot applicable.  
This work was financially supported by the National Natural Science Foundation of China (No. 51864018 and No.52074134) and the project of Jiangxi Provincial Department of Education (No. GJJ150666). The authors declare no conflict of interest.