Process for the purification of lithium carbonate

摘要

Disclosed are methods for preparing high purity lithium carbonate which can be used for pharmaceutical applications, electronic grade crystals of lithium or to prepare battery-grade lithium metal. Lithium carbonate as commercially produced from mineral extraction, lithium-containing brines or sea water, in aqueous solution is used as a feedstock and reacted with carbon dioxide under pressure to form dissolved lithium bicarbonate. Impurities in the lithium carbonate feedstock are either solubilized or precipitated out. Dissolved impurities are physically separated from the lithium bicarbonate using an ion selective means, such as an ion exchange material, or by liquid-liquid extraction. Purified lithium carbonate is then precipitated.