"Experimental Determination of the Electrochemical Properties of Bismut" by Greg Chipman, Bryant Johnson et al.
 

Keywords

Bismuth Chloride, Molten Salt, Diffusivity, Standard Potential, Cyclic Voltammetry, Chronopotentiometry, Liquid Metal, Electrorefining, Pyroprocessing

Abstract

Bismuth has been investigated as a potential liquid electrode for molten salt electrorefining, but the electrochemical behavior of Bi3+/Bi redox couple has received scant attention in eutectic LiCl-KCl melts and no studies were found in the ternary LiCl-KCl-CaCl2 melts. LiCl-KCl-CaCl2 melts offer some advantages over eutectic LiCl-KCl, such as a lower melting point. Cyclic voltammetry, square wave voltammetry, chronoamperometry, chronopotentiometry and open-circuit chronopotentiometry were used to measure electrochemical parameters, such as diffusivity and standard apparent potential of bismuth electrodeposition, in LiCl-KCl and LiCl-KCl-CaCl2 eutectics. The mean diffusivity values of 6.71 x 10-6 cm2 s-1 and 8.93 x 10-6 cm2 s-1 were recommended for BiCl3 in the LiCl-KCl and LiCl-KCl-CaCl2 eutectics, respectively. Although the diffusivity values differed slightly between eutectics, they had too significant of error (± ~30%) to conclusively establish any effect from the presence of CaCl2. The standard apparent potentials of 0.1166 V vs. Ag/AgCl (4.75 mol%) and 0.1187 V vs. Ag/AgCl (4.75 mol%) in the molten LiCl-KCl and LiCl-KCl-CaCl2 eutectics, respectively, at 680 ± 2.1 K were less uncertain (± ~0.5%). These values provide estimates for key properties of the Bi3+/Bi redox couple and their associated errors. Challenges were also identified, most notably the ICP-MS analysis of BiCl3 content, which limited the accuracy of the results. Some improvements were made to the accuracy of the results by utilizing a more thorough drying procedure for CaCl2.

Original Publication Citation

Chipman, G., Johnson, B., Vann, C., Whitesides, L., & Rappleye, D. (2024). Experimental determination of the electrochemical properties of bismuth chloride in eutectic LiCl–KCl and LiCl–KCl–CaCl2 molten salts. Journal of Radioanalytical and Nuclear Chemistry. https://doi.org/10.1007/s10967-024-09354-4

Document Type

Peer-Reviewed Article

Publication Date

2024-02-07

Publisher

Springer Nature

Language

English

College

Ira A. Fulton College of Engineering

Department

Chemical Engineering

University Standing at Time of Publication

Assistant Professor

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