METHOD FOR PRODUCTION OF MAGNESIUM FROM OXIDE-CHLORIDE RAW MATERIAL Russian patent published in 2002 - IPC

FIELD: non-ferrous metallurgy, methods for production of magnesium from oxide-chloride raw material by electrolysis of fused salts. SUBSTANCE: the method consists in grinding of the oxide-chloride raw material, its leading by exit gases with production of a magnesium chloride solution, cleaning, concentration and treatment of the solution by salts containing potassium and magnesium chlorides with production of a mixture of synthetic carnallite of a homogeneous composition, mixing of the mixture with natural enriched carnallite, two-stage dehydration first in the pseudodehydrated layer with production of dehydrated carnallite, then dehydration by chlorination with production of anhydrous carnallite, electrolysis of anhydrous carnallite with production of magnesium, chloride and spent electrolyte, return of part of chlorine to both stages of dehydration, return of spent electrolyte to the stage of mixing, precipitation of dust from exit gases of furnaces with a subsequent direction of exit gases to the stage of leaching of oxide raw material, according to the invention, concentration of the solution is conducted in a tank-scrubber system by its circulation until the content of magnesium oxide in the solution not exceeding 10 g/l is obtained, the obtained magnesium chloride solution is divided into two flows in relation 1: (1-5), one flow is fed to the pseudodehydrated layer, the other - for treatment of the solution by salts at heating for formation of a homogeneous mixture of a solution with salt at the following relation: spent electrolyte: dehydrated carnallite 1.3:0.75, then the obtained mixture is mixed with natural enriched carnallite and at the same time it is fed with the solution to the stage of dehydration to the pseudodehydrated layer at the feed rate of flue gases required for production of the pseudodehydrated layer. EFFECT: reduced specific rates of consumption of raw materials, reclamation of excess chlorine, reduced blowout of gases, reduced outlet of solid and liquid waste. 8 cl, 1 ex