The electrochemical behavior of Fe(III) in molten LiF–NaF–KF [46.5:11.5:42 (mol%)] [FLINAK] salt was studied by cyclic voltammetry (CV), chronopotentiometry (CP) and square wave voltammetry (SWV) at 600°C. It was found that Fe(III) was initially reduced to Fe(II) at +2.0 V (vs. alkalis) followed by reduction of Fe(II) to Fe at +1.4 V (vs. alkalis) and both reduction processes were controlled by ion diffusion. Diffusion coefficients of Fe(III) in molten FLINAK were calculated through CV and CP. The reduction peak of Fe(III)/Fe(II) was still observed in SWVs even though only FeF2 was added to FLINAK. This result showed that Fe(II) was converted to Fe(III), which exists stably in FLINAK melts.
