Lithium is one of the world’s most important minerals because it is used in rechargeable batteries that power electric vehicles, smartphones, laptops, and energy storage systems.
As demand for batteries continues to grow, so does the need for lithium.
Although countries such as the United States and Australia have large lithium reserves, much of the world’s lithium refining is currently done in China.
One reason is that extracting lithium from hard rock is difficult, expensive, and energy-intensive.
Now, researchers at the Massachusetts Institute of Technology (MIT) and their collaborators have developed a new way to extract lithium from hard rock that could dramatically reduce costs and waste.
Their study was published in the journal Science.
The most common lithium-bearing rock is called spodumene. Today, extracting lithium from spodumene usually requires heating the rock to more than 1,000 degrees Celsius before using chemicals to separate the lithium.
This process consumes large amounts of energy and leaves behind significant waste.
The MIT team has developed a much simpler approach. Instead of using extreme heat, they use a liquid mixture made from water and ammonium fluoride to dissolve the rock at room temperature.
This process not only releases lithium but also separates the other valuable materials contained in the rock, including aluminum and silica. The lithium can be turned into battery-grade lithium salts, while the aluminum and silica can be used in industries such as metal production and cement manufacturing.
Researchers say the process creates very little waste because the chemicals used can be recovered and reused in a closed-loop system.
According to the team, the new method could reduce extraction costs by about 50% compared with conventional hard-rock lithium processing. It may even become competitive with lithium production from underground brine deposits, another major source of lithium that also raises environmental concerns.
The idea for the process has an unusual origin. About 25 years ago, MIT professor Yet-Ming Chiang came across a glass-etching cream while renovating a bathroom. The cream contained ammonium fluoride, a chemical that dissolves silica, one of the main ingredients in glass.
Years later, Chiang realized the same chemistry might help break apart spodumene. Since silica is also a major component of lithium-bearing rock, the researchers wondered whether they could dissolve the silica first and then separate the remaining materials.
The strategy worked. The team successfully tested the process on 17 different spodumene samples from around the world, showing that it could be widely applied.
The researchers then spent years refining the method to ensure the lithium, aluminum, and silica products met commercial quality standards. They also developed a way to recycle the ammonium fluoride and water used during processing, making the system highly efficient.
To bring the technology to market, the researchers have launched a startup called Rock Zero, which is working to scale up the process.
The team believes their approach could provide a cleaner, cheaper, and more sustainable way to produce lithium at a time when the world needs far more batteries to support the transition to cleaner energy.
