Current status and progress of research on vacuum method of refining magnesium

Magnesium plays an important role in biomedicine, new energy vehicles, aerospace and other fields because of its excellent physical and chemical properties. China is a major source of magnesium worldwide, with the output of primary magnesium accounting for >80% of the world’s total annual output. The smelting process represented by the Pidgeon process plays the leading role in China because of its simple process flow and equipment and the flexibility of the production scale. However, the Pidgeon process always has the problems of low utilization of reduction heat, a short lifetime of the reduction tank, a high cost of the reduction furnace, and a discontinuous production process. Therefore, how to produce magnesium in a clean, efficient and continuous manner has been the focus of industry development research. In this work, from the perspective of the preparation of magnesium by thermal reduction, the production of high-purity magnesium, and the recycling of waste magnesium alloys, the research status of magnesium preparation by direct vacuum and relative vacuum processes was reviewed, including the reduction mechanism, migration and condensation patterns and production efficiency of magnesium. The effects of the reducing agent, reduction temperature, holding time and other factors on the preparation of magnesium were emphasized. Finally, by comparing the production processes of magnesium by direct vacuum and relative vacuum methods, the advantages and disadvantages of the two methods for the preparation of magnesium were mainly discussed, and the future development of magnesium was proposed.