Critical review of magnesium-based thermochemical and electrochemical reduction routes for sustainable non-ferrous metal production

This review critically evaluates Mg-mediated routes for producing non-ferrous metals and related materials, including magnesiothermic extraction and MgCl 2 -assisted electrochemical processing. The discussion first clarifies the thermodynamic basis and metallurgical significance of Mg before analyzing the reaction pathways, kinetics, and transport limitations in direct solid-state reduction and gas-phase Mg infiltration. Mg-mediated extraction of Ti, Zr, rare earth elements, Nb, Ta, and Si is subsequently examined with emphasis on the coupling of reduction behavior with separation, purification, morphology control, and by-product management. The review also assesses engineering barriers, including Mg vapor containment, reactor corrosion, MgO separation, and the energy penalty of Mg regeneration. Electrochemical processing in molten halides is discussed with particular attention to MgCl 2 as a chlorinating agent, an electroactive melt component, and a functional additive that improves process feasibility and efficiency. Finally, future directions are outlined for closed-loop Mg metallurgy and hybrid thermochemical-electrochemical extraction, focusing on electrolysis hardware, Mg recovery, and heat integration. By linking magnesiothermic reduction with molten-halide electrochemistry, this review positions Mg as both an effective reductant and a recyclable redox carrier for low-carbon non-ferrous extractive metallurgy.