Process for the preparation of anhydrous magnesium chloride having a

Abstract

Anhydrous magnesium chloride containing substantially no magnesium oxide is produced by a process comprising reacting magnesium chloride in the form of its hexahydrate with ammonia in the presence of ammonium chloride in an aqueous media; separating the resultant precipitated magnesium chloride hexammoniate crystals from an aqueous solution containing unreacted ammonia, magnesium chloride and ammonium chloride; washing the crystals with liquid ammonia; decomposing the washed crystals into anhydrous magnesium chloride and gaseous ammonia, and; isolating the anhydrous component from the composition mixture; which process is characterized in that a portion of the separated aqueous solution is evaporated until the concentration of ammonia in the resulting residual liquid becomes 2.5% or less; the residual liquid is mixed with fresh magnesium chloride so as to dissolve it in the liquid; the resultant solution is fed into the reacting step, and; the remaining portion of the separated aqueous solution is directly recycled into the reacting step.