7. Obtaining lithium metal

Lithium metal is obtained from LiCl obtained from Li ₂ CO ₃ .

Lithium carbonate is first purified to remove impurities interfering with electrolysis and the purity of the final lithium, in particular sodium, calcium, magnesium and sulfate ions. The most widely used process is the CO ₂ process. It involves solubilizing lithium in bicarbonate form by adding CO ₂ operating on a suspension of lithium carbonate in water. After filtration to remove precipitated impurities, lithium is precipitated from the filtrate in the form of carbonate by thermal decomposition at 90°C of the bicarbonate. The purified carbonate is converted to chloride by reaction with hydrochloric acid. Due to the strong...