Fluid Bed Dehydration of Magnesium Chloride

Molten salt electrolysis of MgCl2 is commonly used for the production of Magnesium metal. However, the electrolysis feed must be completely dry with minimum oxygen content. Therefore, complete dehydration of the MgCl2 brine or the hydrated salt is a required process, which is very challenging due to the ease of thermal degradation. Fluidized bed dryers are often used, under air and HCl environments. The key features of three different types of fluid bed technologies, which can be applied to MgCl2 dehydration plants, are described in this paper. In addition, a discussion of chemistry, unit operations and advantages associated with each option, is presented. The background information is provided based on open literature sources, including papers and patents. Most calculations are performed using commercially available metallurgical software, for the thermodynamics and mass/heat balances.