Multi-physics modeling of molten salt transport in solid oxide membrane (SOM) electrolysis and recycling of magnesium

Solid Oxide Membrane (SOM) Electrolysis offers a novel energy-efficient zero-emissions technique for producing high-purity magnesium and oxygen directly from industrial-grade MgO. This study investigates SOM Recycling, which integrates SOM electrolysis with electrorefining, to continuously derive high-purity magnesium from low-purity partially oxidized scrap. Both processes occur in a crucible where raw materials are fed into a molten salt electrolyte, generating magnesium vapor at the cathode and oxygen at the inert anode. We present a three-dimensional multi-physics finite-element model that simulates ionic current, fluid dynamics instigated by argon bubbling and thermal buoyancy, alongside heat and mass transport within the crucible. The simulation elucidates the impacts of stirring on the boundary layer at the anode and its temporal development, as well as the influence of natural convection along the outer wall. The developed model serves as an instrumental tool for the scale-up design of these interconnected processes, thus contributing significantly to advancements in sustainable magnesium production.