Abstract: A method of producing magnesium and chlorine including the steps of injecting concentrated magnesium chloride containing brine into a hot gas spray drier wherein most of the water is evaporated to produce cell feed in the form of a powder of high porosity discrete particles of impure MgCl.sub.2, the impure particles being purified by in situ reaction within an electrolytic cell by depositing the particles onto an area of the surface of molten electrolyte whereby a portion of the entrained impurities are vaporized and withdrawn and circulating the electrolyte through the interelectrode space where the remaining impurities are chlorinated by chlorine gas produced at the anode, the circulation being at a rate to entrain most of the magnesium oxide particles in suspension for reaction with chlorine gas generated at the anode element. The molten magnesium produced at the cathode is withdrawn in the usual manner.