Origin and properties – Lithium was discovered in 1817 by Johan Arfvedson. One year later William Brande and Humphrey Davy succeeded in creating a metallic representation of the element. Its name comes from the Greek (‘lithos’) and means stone. In nature, it only occurs in compounds due to its high chemical reactivity. In the earth’s crust it occurs in a concentration of 17 ppm. Economically usable concentrations of lithium are found in so-called pegmatites as well as in brines (either as continental brines in the form of so-called salares or as a by-product of oil production and there dissolved in the reservoir water). Lithium is also the lightest metal in the universe and is found in the periodic table of the elements after hydrogen and helium. It is composed of three protons (Gunn 2014).
Pegmatites are coarse-grained, magmatic rocks which are formed by late crystallization of the magmatic residual melt. Lithium pegmatites are relatively rare, although lithium usually occurs together with tin and tantalum. The most common lithium mineral of pegmatitic deposits is spodumene (with a lithium content of 3.7%). Other lithium containing minerals are petalite, lepidolite and Zinnwaldite (Gunn 2014).
Lithium-containing brines (or continental brines) are formed in continental basin structures (i.e. morphological landscapes framed by elevations or mountains on all sides), whereby surface water and groundwater from the surrounding formerly volcanically formed mountains accumulate eroded and washed out lithium over geological periods. During this process, lithium and other economically important elements such as boron and potassium are enriched by high rates of evaporation (Gunn 2014).