Rare Earth Chlorides in Low-Hydration Magnesium Chloride Electrolysis: Mechanistic Insights

During the molten salt electrolysis of magnesium production, water in the magnesium chloride (MgCl 2 ) feedstock poses significant interference, reducing the current efficiency. Employing rare earth chlorides (RECl 3 ) to assist in dehydrating MgCl 2 and producing Mg-RE master alloys emerges as an effective strategy. This study investigated the transformation process in the hydrolysis reaction of low-hydrate MgCl 2 within the molten salt, examining the electrochemical activity of its hydrolysis products using Cyclic voltammetry (CV). Additionally, a thermodynamic analysis of the reaction between hydrolyzate MgO and RECl 3 was performed at electrolysis temperatures. By integrating CV and Square wave voltammetry (SWV) with X-ray diffraction (XRD) analysis, the study explored the alterations in the electrochemically active components of the molten salt system following the addition of RECl 3 to the KCl-NaCl molten salt containing MgO.