The element lithium has become a foundational material for modern technology, powering the global shift toward electrification. This soft, silvery-white metal is the least dense of all metals, allowing rechargeable lithium-ion batteries to store significant energy while remaining lightweight and compact. These high-performance batteries are used in everything from smartphones and laptops to grid-scale energy storage systems, but their largest demand driver is the rapidly expanding electric vehicle market. The batteries themselves are not mined; rather, the raw material, lithium, must first be extracted from the earth and then chemically processed into a usable form.
Where Lithium is Found
Lithium is never found in its pure metallic form due to its high reactivity, but it is the 33rd most abundant element in the Earth’s crust, occurring in two primary geological forms. The first source is lithium-enriched brine, which is saltwater containing high concentrations of dissolved lithium salts. These brine deposits are primarily found beneath vast salt flats, known as salars, in arid, high-altitude regions.
The most notable location is the “Lithium Triangle” in South America (Chile, Argentina, and Bolivia), which holds a significant portion of the world’s lithium reserves. The second major source is hard rock deposits, where lithium is locked within mineral ores like spodumene. Australia is currently the world’s largest hard rock producer, though significant deposits also exist in Canada and China.
Extracting Lithium from Brine
The extraction of lithium from brine relies heavily on natural solar energy. Production begins by drilling wells to access the lithium-rich brine held in underground aquifers beneath the salt flats. This saline water is then pumped to the surface and channeled into evaporation ponds.
Over a period that can last from 18 to 24 months, the intense sunlight and arid climate cause the water to evaporate slowly. As the water disappears, the concentration of various salts increases, and unwanted elements like sodium and potassium precipitate out first. Hydrated lime (calcium hydroxide) is often added to chemically remove impurities such as magnesium. The remaining solution, now highly concentrated in lithium chloride, is then transferred to a recovery facility for final processing.
Mining Lithium from Hard Rock
Extracting lithium from hard rock deposits relies on mechanical and thermal processes instead of solar evaporation. Deposits of the lithium-bearing mineral spodumene are typically accessed through large open-pit mines, involving traditional methods of blasting and quarrying to remove the ore.
The ore is then transported to a processing facility where it undergoes crushing and grinding to reduce it to a fine powder. The next step is called beneficiation, which separates the spodumene from the surrounding waste rock using techniques like froth flotation or heavy media separation. This process creates a spodumene concentrate containing about 5 to 7% lithium oxide, which is then ready for a high-temperature treatment known as calcination, a precursor to chemical refining.
Refining Lithium for Battery Use
Regardless of whether the lithium originated from brine or hard rock, the final stage is chemical conversion to produce battery-grade material. The crude lithium compounds must be transformed into either high-purity lithium carbonate (Li2CO3) or lithium hydroxide (LiOH), which are the forms used in battery cathodes.
The concentrated lithium chloride solution from brine is commonly treated with soda ash (sodium carbonate) in a chemical reaction that causes lithium carbonate powder to precipitate out. For hard rock concentrates, the initial thermal treatment converts the raw spodumene into a more reactive form that can be leached with sulfuric acid to create a lithium sulfate solution. This solution is then purified to remove contaminants.
The purified lithium sulfate can be chemically converted into lithium carbonate, or further processed using a lime conversion step to produce lithium hydroxide. Lithium hydroxide is increasingly favored for high-performance electric vehicle batteries.