中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 5 May 2025 |
（1. National Engineering Research Center for Integrated Utilization of Salt Lake Resource, East China University of Science and Technology, Shanghai 200237, China;
2. Joint International Laboratory for Potassium and Lithium Strategic Resources, East China University of Science and Technology, Shanghai 200237, China）
Abstract:A comprehensive electrochemical assessment of Fe2+ behavior in a MgCl2-NaCl-KCl melt was reported, involving cyclic voltammetry (CV), square wave voltammetry (SWV), and chronoamperometry (CA) analyses. Reduction of Fe2+ in MgCl2-NaCl-KCl was observed to occur in a single step involving two electrons, exhibiting quasi-reversible behavior. The diffusion coefficient of Fe2+ (5.75×10-5 cm2/s) in this system was experimentally determined at 973 K, with an associated diffusion activation energy of 25.06 kJ/mol in the range of 973-1048 K, and an estimated standard rate constant for Fe2+/Fe of around 1×10-3 cm/s. The nucleation of Fe on the tungsten electrode in the MgCl2-NaCl-KCl molten salt is insensitive to temperature and overpotential. It is found that the nucleation mode is related to the concentration of Fe2+ surrounding the electrode and evolves from an instantaneous to a progressive process, accompanied by a deterioration of magnesium electrolysis due to Fe impurities.
Key words: Fe2+; MgCl2-NaCl-KCl melt; electrochemical reduction; kinetic properties; nucleation mechanism
