Characterization and removal of oxygen ions in LiF-NaF-KF melt by electrochemical methods

LiF-NaF-KF melt is used to investigate the feasibility of using electrochemical methods to characterize and remove trace amounts of oxygen ions. Electrochemical methods including cyclic voltammograms and chronoamperometry are applied to characterize the oxidation processes of the trace oxygen ions in LiF-NaF-KF melt. The results show that the anodic peak currents vs. the square roots of scan rates is linearity passing through the origin, indicating the oxidation of oxygen ions is controlled by ions diffusion process. The dependency of the anodic peak currents vs. the concentrations of oxygen ions is also linearity when the concentration is no more than 1200 ppm. So the anodic peak current can be used to determine the oxygen ions content in the melt online. The peak currents of oxygen ions oxidation are gradually reduced after 3 h, 8 h and 20 h constant-potential electrolysis. Oxygen ions concentration is reduced to 200 ppm in LiF-NaF-KF melt after 20 h constant-potential electrolysis.

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