Lithium is widely distributed on Earth and is the 33rd most abundant element;however, it does not naturally occur in elemental form due to its high reactivity. Estimates for crustal content range from 20 to 70 ppm by weight. In keeping with its name, lithium forms a minor part of igneous rocks, with the largest concentrations in granites. Granitic pegmatites also provide the greatest abundance of lithium-containing minerals, with spodumene and petalite being the most commercially-viable mineral sources for the element.
Lithium metal, due to its alkaline tarnish, is corrosive and requires special handling to avoid skin contact. Breathing lithium dust or lithium compounds (which are often alkaline) can irritate the nose and throat; higher exposure to lithium can cause a build-up of fluid in the lungs, leading to pulmonary edema. The metal itself is usually a handling hazard because of the caustic hydroxide produced when it is in contact with moisture causing an explosion. Lithium should be stored in a non-reactive compound such as naphtha or a hydrocarbon
Most lithium comes from South America, where the cheapest extraction method evaporates salty brine in ponds lined with toxic PVC, Erceg said. And in lithium-rich regions of Chile, mining the material uses two-thirds of the area's drinking water.
Erceg described another exploratory method--of piping in ocean water to mine minerals--as inefficient because it requires treating the saline water first.