Low-Cost Magnesium Primary Production Using Gravity-Driven Multiple Effect Thermal System (G-METS) Distillation

Vapor compression distillation (VCD) in a gravity-driven multiple-effect thermal system (G-METS) distiller can reduce the energy use and cost of magnesium distillation refining by up to 90% versus today’s batch distillation processes. This could potentially provide a key unit operation for efficient primary production of magnesium from MgO, by molten salt electrolysis using a reactive cathode, e.g., liquid tin followed by VCD separation. This work presents a techno-economic model of cost, energy consumption, and emissions associated with magnesium primary production by this reactive cathode molten salt electrolysis process with a G-METS distiller. The model includes a mass balance with 17 elements, electrolysis process energy balance with carbon or solid oxide membrane anodes, and detailed operating and capital cost estimates. Based on the properties of magnesium and expected operating conditions, the cost of magnesium production using this process could be comparable to or lower than that of aluminum production.