Carbothermal Production of Magnesium in Vacuum

摘要

Carbothermal production has been recognized as conceptually the cleanest and energy-efficient route to magnesium metal, but has suffered from technical challenges of development and scale-up. Work by National Engineering Laboratory for Vacuum Metallurgy of China has overcome some barriers of carbothermal production. By changing the condition of condensation, the magnesium vapor is condensed into bulk, so that the risk of magnesium powder explosion can be avoided, and it can reduce the oxygen content, enhance the recovered of magnesium. The mechanism of the carbothermic reduction process has be investigated, the reversion reactions are favored below 1373K at 30～100Pa, and reversion below 9% at bulk in condensation. Purification of magnesium by distillation is known technology, but difficulties with continuous operation are also known. In terms of process control, distillation temperature and pressure are controlled, the magnesium vapor is condensed into liquid, and then solidified into a solid, the solid magnesium is purified (>99.9%).