Lithium, the lightest metal, is a cornerstone of the modern battery industry, enabling the rise of electric vehicles and large-scale energy storage solutions. It was fascinating to read more on the primary lithium extraction methods and their associated costs.
Pegmatites (Hard Rock)
Pegmatites are igneous rocks that contain high concentrations of lithium-bearing minerals such as spodumene. The extraction process involves traditional mining techniques, where the ore is blasted, crushed, and then subjected to thermal treatment (calcination) to convert the lithium crystal phase, making it water-soluble for leaching and extraction.
- Relative Cost: High - The process is energy-intensive and requires significant capital investment in mining equipment and facilities.
Lithium brines are perhaps the most well-known sources of lithium, found in salt flats like the famous Atacama Salar in Chile. These brines are rich in dissolved lithium salts, which are pumped to the surface and transferred to large evaporation ponds. Over months, the water evaporates, and the lithium concentration increases until it can be processed and refined.
- Relative Cost: Medium to Low - This method is generally less expensive thanks to the passive solar evaporation technique. However, it is time-consuming and requires large tracts of land for evaporation ponds.
Lithium can also be found in hectorite clay deposits. Unlike hard rock or brine sources, extracting lithium from clay involves a process known as acid leaching, where the material is excavated and treated with acid solutions to dissolve the lithium, which is then precipitated out and refined.
- Relative Cost: High - The extraction from clays is chemically complex and often more costly than brine solutions. It can also have greater environmental impacts due to the acid leaching process.
A more recent and environmentally friendly source of lithium is geothermal brines, which are a byproduct of geothermal energy production. These brines are already being pumped to the surface as part of energy extraction, and they contain dissolved lithium, which can be extracted on-site.
- Relative Cost: Medium to High - The technology for extracting lithium from geothermal brines is still being developed and refined, so costs can vary. However, the dual benefit of energy and lithium production may offset the overall costs.