Sources of Lithium
Lithium is found in economic concentrations in the following sources:
Lithium-bearing, hard-rock pegmatites, such as those at Greenbushes and Novo Lítio’s Sepeda Lithium Project in Portugal, account for over a third of global production. Although lithium occurs in some 145 minerals, spodumene and petalite (both lithium aluminium silicates) make up the majority of production, as both are easy to process into lithium carbonate using commercially proven methods. Other minerals such as lithium micas (lepidolite and zinnwaldite) and clays are more complicated/energy intensive to process, with lithium micas generally also containing hazardous fluorine, and have historically not been the preferred sources of lithium as a result.
As processing methods are simple, hard-rock, pegmatite-hosted lithium sources such as spodumene or petalite have a much lower capex but higher opex relative to brines, and also benefit from a potentially much shorter time from discovery to production.
Petalite and some lower-iron sources of spodumene also benefit from being able to be sold into the premium technical grade market as a concentrate, as well as processed to a battery-grade lithium carbonate product, giving producers greater flexibility.
Lithium is found in commercial quantities in some continental brine deposits of volcanic origin, and in desert areas in playas and saline lakes where lithium has been concentrated by evaporation. These range in concentration from Clayton Valley, USA, at 0.02% Li, to Salar de Atacama in Chile, with 0.14% Li. The process of extracting the lithium from brines involves pumping into a series of evaporation ponds to crystallize other salts, leaving a lithium-rich liquor. After 9-12 months, depending on climate, a concentrate of 1 to 2% lithium is further processed in a chemical plant to yield various end products, such as lithium carbonate and lithium hydroxide. Nearly one half of the world’s lithium supply comes from brine production in Chile and Argentina. Brine projects generally have a much higher capex than pegmatites, and take longer to start producing. However, they benefit from a lower opex relative to spodumene/petalite.
Sedimentary rock deposits account for 8% of known global lithium resources and are found in clay deposits and lacustrine evaporites.
The most commonly-known form of lithium-containing lacustrine deposit is found in the Jadar Valley in Serbia for which the lithium- and boron-bearing element jadarite is named. The extraction of lithium from jadarite has not been commercially proven yet. Other sources of clay-hosted lithium are also found in Mexico.
5 Benchmark Minerals, 2015
6 Fox Davies, 2013