FIELD: winning of magnesium by electrolytic method. SUBSTANCE: process includes preparation of carnallite from solution, separation of mother liquor and carnallite, dehydration of the latter by heated gases, electrolysis with production of magnesium, chlorine and spent electrolyte, total or partial return of the latter into process, reduction of chlorine generated by electrolysis to hydrogen chloride by feed of chlorine into high-temperature furnace into burning flame of hydrogen-carrying fuel. Mother liquor and carnallite are separated by settling and/or centrifugation. Hydrogen-carrying fuel is burnt with primary air. Heat transfer agent of high-temperature furnace is cooled by secondary air. Synthetic carnallite is dehydrated by obtained mixture in fluidized bed thanks to heat of this mixture or by additional supply of part of heat to carnallite by contact method from heating devices placed in fluidized bed or contacting it. Then hydrogen chloride is absorbed from dehydration waste gases by means of aqueous solution circulating in gas cleaning system till hydrochloric acid of specified concentration is produced. Later it is used to treat oxygen compounds of calcium and magnesium separately or jointly or to absorb hydrogen chloride directly from waste gases of dehydration with pulp containing oxygen compounds of calcium and magnesium. In this case potassium chloride, magnesium chloride, sodium chloride and calcium chloride are injected in ratios listed below ensuring content of components in synthetic carnallite coming for dehydration, per cent by mass: potassium chloride 21.0-25.0; magnesium chloride 30.0-32.0; sodium chloride 3.5-9.0; calcium chloride 0.3-2.0; water being the balance. EFFECT: increased degree of extraction of magnesium, reduced specific consumption of fuel and electricity. 7 cl, 3 tbl
