Anhydrous magnesium chloride process

Abstract

Anhydrous magnesium chloride may be prepared for magnesium chloride hydrate by the following sequence of process steps: A. mixing together a magnesium chloride hydrate said hydrate containing minor amounts of water soluble sulfate and boron compounds as impurities with diethyl ether of tetraethylene glycol to prepare 0.1 - 6.0% by weight slurry of MgCl.sub.2 in the diethyl ether of tetraethylene glycol and an azeotropic agent having a boiling point less than the diethyl ether of tetraethylene glycol in a quantity sufficient to remove water from said slurry; B. distilling water from said slurry wherein an anhydrous solution of MgCl.sub.2 in diethyl ether of tetraethylene glycol containing the water soluble sulfate and boron compounds as insoluble impurities is formed; C. separating said MgCl.sub.2 solution from the insoluble impurities; D. adding to the MgCl.sub.2 solution about 3.0 moles of ethylene glycol per mole of MgCl.sub.2 present so as to prepare a MgCl.sub.2.3 moles ethylene glycol complex precipitate; E. separating precipitate pecipitate from the diethyl ether of tetraethylene glycol and recovering the precipitate; F. dissolving said precipitate in ethylene glycol to prepare a solution of the precipitate in ethylene glycol said ethylene glycol being used in a quantity so as to prepare an ethylene glycol solution containing from 1 to 20% by weight MgCl.sub.2 ; G. treating the ethylene glycol magnesium chloride solution with ammonia to form a magnesium chloride-ammonia complex which is insoluble in the ethylene glycol with the temperature of the ethylene glycol magnesium chloride solution being within the range of between -15.degree. to 50.degree.C; H. separating the magnesium chloride-ammonia complex from the ethylene glycol; I. washing the magnesium chloride-ammonia complex with a polar solvent having a lower boiling point than ethylene glycol to remove any ethlene glycol entrained in the magnesium chloride-ammonia complex; J. heating the magnesium chloride-ammonia complex to a temperature sufficient to drive off the ammonia for a sufficient period of time to remove the ammonia, thereby forming anhydrous magnesium chloride; and then, K. recovering anhydrous magnesium chloride which has a magnesium oxide content of less than 0.8% by weight and which is substantially free of impurities.

Dependencies are inferred from the claim text.