WHAT IS LITHIUM

Lithium was discovered in 1817 in Stockholm, Sweden by Johan August Arfvedson, who was analyzing a petalite ore. However, Arfvedson was unable to isolate lithium in its pure form; Sir Humphrey Davy and W.T. Brande achieved that in 1855 when they performed electrolysis on lithium oxide. Lithium's properties were first mined commercially in 1923 by Metallgesellschaft AG in Germany using the electrolysis of a molten mixture of lithium chloride and potassium chloride.

Lithium is a solid soft alkali metal which has an atomic number of 3 and is the lightest of all metals, with a density of about half of that of water.  The metal is naturally occurring in minute amounts in ore and brine deposits.  The major ores used to mine lithium are spodumene, petalite and lepidolite.  While spodumene is the most common lithium ore mined, it is also more expensive than mining brine deposits as the process is more complicated as illustrated below:

1. Spodumene (Li₂OAl₂O₃.4SiO₂ ) is crushed and undergoes flotation beneficiation to produce a concentrate.

2. The concentrate is heated to 1,100 degree to make it more reactive with sulphuric acid and produces lithium sulphate.

3. Water is added to make the lithium sulphate in liquid form and is exposed to sodium carbonate which produces the liquid sodium sulphate and the precipitate lithium carbonate.

Li₂SO₄ + Na₂CO₃  =  Na₂SO₄ + Li₂CO₃ (solid)

4. Lithium carbonate and hydrochloric acid are mixed to produce lithium chloride, carbon dioxide and water.

Li₂CO₃ + 2HCl  = 2LiCl + CO₂ + H₂O

5. The lithium is separated into pure lithium metal using electrolysis.

Cathode Li⁺ + e^- Li

Anode Cl^- 1/2Cl₂ +e^-

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