METHOD OF TREATING OXIDE MAGNESIUM-CONTAINING RAW MATERIAL BEFORE ELECTROLYSIS Russian patent published in 2003 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: in a method including etching with hydrochloric acid, removal impurities from magnesium chloride solution, and magnesium chloride dehydration in multicell heater, magnesium chloride solution, prior to be dehydrated, is mixed with molten electrolyte of magnesium electrolyzers (no more 10% MgCl₂) and resulting suspension is supplemented by partially dehydrated product (at least 20% water and no more than 0.2% MgO) from heater, in particular, from first-cell bed or in the form of dust trapped in gas-cleaning cyclones of the first heater cell, in amounts high enough to form solid crystal hydrates. Velocity of heat carrier in the first heater cell is maintained between 0.5 and 1.8 nm/s. Dehydration of solid crystal hydrates obtained from salt suspensions in heater is performed in common with concentrated carnallite. Further dehydration of partially dehydrated product is carried out in multicell chlorinator, into which chlorine and hydrogen- containing gas are fed at first-cell temperature no higher than 550 C and last- cell temperature no less 700 C. EFFECT: enabled use of exhausted electrolyte during treatment of oxide magnesium-containing material before electrolysis. 7 cl, 1 dwg, 2 ex