Pure magnesium chloride prepared by the simultaneous extraction and azeotropic drying of a salt mixture

Claim 1

PROCESS FOR THE REMOVAL OF WATER OF HYDRATION FROM HYDRATED MAGNESIUM CHLORIDE WHICH COMPRISES CONTACTING THE SAME IN AN EXTRACTION-DISTILLATION ZONE IN THE PRESENCE OF A MAGNESIUM CHLORIDE SOLVENT UNDER TEMPERATURE AND PRESSURE CONDITIONS TO REMOVE OVERHEAD AS AN AZEOTROPIC DISTILLATION THE WATER OF HYDRATION TOGETHER WITH SOME MAGNESIUM CHLORIDE SOLVENT, WITHDRAWING THE MAGNESIUM CHLORIDE SOLUTION FROM THE EXTRACTION-DISTILLATION ZONE AND FILTERING THE SAME IN ORDER TO REMOVE UNDISSOLVED IMPURITIES THEREFROM, THEREAFTER TREATING THE SOLUTION IN A SECOND DISTILLATION ZONE UNDER CONDITIONS TO REMOVE OVERHEAD A PORTION OF SAID MAGNESIUM CHLORIDE SOLVENT, WITHDRAWING THE REMAINDER OF THE MAGNESIUM CHLORIDE SOLUTION FROM THE BOTTOM OF SAID SECOND DISTILLATION ZONE AND CONTACTING THE SAME IN A PRECIPITATION ZONE WITH AMMONIA WHEREBY AN INSOLUBLE MAGNESIUM CHLORIDE HEXAMMONIATE FORMS, SEPARATING THE PRECIPITATE AND THEREAFTER TREATING THE MAGNESIUM CHLORIDE AMMONIATE IN A FIRST STAGE OF A DECOMPLEXING ZONE WITH AMMONIA SO AS TO REMOVE ALL TRACES OF SAID MAGNESIUM CHLORIDE SOLVENT THEREFROM, SUBJECTING THE PARTIALLY DECOMPLEXED AMMONIATE IN A SECOND STAGE OF SAID DECOMPLEXING ZONE TO TEMPERATURE AND PRESSURE CONDITIONS TO REMOVE AMMONIA AND TO PRODUCE ANHYDROUS MAGNESIUM CHLORIDE.