Lithium is the lightest solid element in the periodic table. The soft, silvery-white alkali metal was discovered by a Swedish chemist, Johan Arfwedson, in 1817. But it took decades – up until 1923 – before scientists could isolate it on an industrial scale via electrolysis.
The two main natural sources from which lithium is extracted are minerals (hard-rock) or salt solutions (brines).
The mining of pegmatitic minerals containing spodumene (LiAl(SiO3)2) is mainly located in Western Australia. Via a series of mechanical purification and separation steps the Lithium in the mined minerals can be concentrated. The attained spodumene concentrate can be directly used in e.g. the glass industry or can be further refined into a Lithium chemical.
Although Lithium thanks its name to the Greek word lithos which means stone, the largest part of the industrially used Lithium is extracted from brines. The majority of these salt solutions are found in the salt flats that cover parts from Chile, Argentina and Bolivia: the so-called Lithium triangle. The dissolved Lithium in brines is concentrated by solar evaporation, followed by a combination of precipitation and filtration steps to remove residual impurities like Calcium, Magnesium and Boron. The purified LiCl solution can then be used to make a variety of Lithium chemicals (e.g. Li2CO3 and LiOH).
- The main problem with the isolation of Lithium in its metallic form is its high reactivity and flammability. Consequently, you won’t find this element as a pure metal in nature but as a compound or in its soluble ionic form.
- Compared to other alkali metals however, Lithium is less reactive due to its small atomic radius (152 pm) and the proximity of its single valence electron to the nucleus which stabilizes the electron.
- Other properties that make Lithium a unique element are its low density (0.534 g/cm3) and its high specific heat capacity (3.58 kJ/(kg K), the highest of all solids. This has led to a variety of industrial applications that use Lithium.
- The Li-ion battery industry is the largest consumer of Lithium worldwide, mainly for the production of active cathode materials for Li-ion batteries, where Lithium is used in the form of highly pure Li2CO3 or LiOH.
- Besides the Li-ion battery industry, Lithium has been used for many years in other, more traditional applications like in glasses and ceramics, in mold flux powders and in Aluminum smelting.
- Other applications that consume lithium are greases for mechanical systems (e.g gear boxes), catalysts for rubber synthesis (Butyllithium), Aluminium alloys for airplanes, air cooling systems (Lithium Bromide) and antidepressants.
Due to the abundancy of Lithium in nature, the recycling of Lithium had no priority for the many players in the Lithium-ion battery, glass, ceramic, industry. The recent Lithium demand increase for electric vehicles emphasized the importance of recycling. Now, both pyro metallurgical as hydro metallurgical flowsheets are able to recycle Lithium from Li-ion battery waste.