METHOD OF PRODUCTION OF HIGH-PURITY LITHIUM HYDROXIDE FROM NATURAL BRINES Russian patent published in 2000 - IPC

FIELD: chemical technology of production of lithium compounds from natural brines containing halides (chlorides and bromides) of lithium, potassium, calcium and magnesium; production of high-purity lithium hydroxide. SUBSTANCE: method includes electrochemical conversion of mixture of lithium chloride with lithium carbonate both in presence of reductant and without it. Lithium chloride is produced by passing the brine through layer of inorganic sorbent followed by elution of lithium with water, thus obtaining solution of lithium chloride and cleaning the eluate from admixtures on cationite. Electrolysis is performed at current density of 3 to 30 A/sq.dm. Crystallization of lithium hydroxide is performed at carbonization of part of LiOH solution, thus obtaining lithium carbonate. Waste chlorine is entrapped by bromine-containing brine. Cathode hydrogen is burnt and heat is used for additional strengthening the solution of lithium hydroxide. EFFECT: enhanced efficiency. 2 cl, 3 dwg, 2 tbl, 7 ex