Extraction of lithium from spodumene, often SC6, is challenging due to the tight binding of lithium in the
crystal structure. Traditional lithium refining in the 2010s involves acid
leaching of lithium-containing ores, precipitation of impurities, concentration of the lithium solution, and then conversion to
lithium carbonate or
lithium hydroxide. These refining methods result in significant quantities of caustic waste effluent and
tailings, which are usually either highly acidic or alkali. Another processing method relies on
pyrometallurgical processing of SC6—roasting at high temperatures exceeding to convert the spodumene from the tightly bound alpha structure to a more open beta structure from which the lithium is more easily extracted—then cooling and reacting with various
reagents in a sequence of
hydrometallurgical processing steps. Some offer the use of noncaustic reagents and result in reduced waste streams, potentially allowing the use of a closed-loop refining process.
Tesla has developed and, as of 2025, is operationalizing at scale, a similar 6-8 step process of lithium refinement that does not require acids. They mix
sodium chloride with the open-beta-structure spodumene concentrate and water. Agitation at high temperatures produces a lithium-rich slurry that can be filtered and purified into
lithium hydroxide. Waste products include
analcime, sands and limestone, which can be repurposed as construction materials. A Tesla refinery located on 1,200 acres in
Robstown, Texas, uses this process. It began partial operation in December 2024. The site was chosen for its proximity to the
Port of Corpus Christi, where spodumene can conveniently be imported. A common form of refined lithium from both of the above processes is
lithium hydroxide, commonly used as an input in the battery industry to manufacture
lithium-ion (Li-ion) battery
cathode material. ==Gemstone varieties==