Magnesium Chloride Dehydration using the Fluidized Bed Technology
Authors: K. Adham, C. Lee and K. O'Keefe

Abstract

Magnesium metal is commonly produced through the molten salt electrolysis of MgCl₂. The feed to electrolysis must be dry with minimum oxygen content. Drying the brine or the hydrated chloride prill (MgCl₂-6H₂0) is a challenging process, due to the great tendancy of MgCl₂ to undergo pyrohydrolysis (thermal degradation with H₂0), when heated. Fluidized bed dryers are often used (under air or HCl environment) to achieve the target drying.

This paper addresses the key features of the three (3) different types of fluid bed technologies which can be applied to MgCl₂ dehydration plants, with a discussion of chemistry, unit operation and advantages associated with each option. All the background information has been obtained from the relevant open literature sources (papers and patents), and most calulations have been performed using the commercially available metallurgical software, Metsim® and HSC®.