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MIT researchers recently created a new method to extract lithium from spodumene rock using a low-temperature process. A bathroom renovation inspired the research. At the time, Yet-Ming Chiang, MIT’s Kyocera Professor of Materials Science and Engineering, noticed that glass etching cream dissolves silica. The researchers then created a similar liquid solution that dissolves silica in spodumene rock. With this technology, we could see hard rock lithium resources in North America and create a sustainable supply for the battery industry.
“By 2040, we need to quadruple production of lithium globally, which amounts to hundreds of new lithium producing assets,” says author Camden Hunt, a former project manager in MIT’s Center for Electrification and Decarbonization of Industry. “Hard rock is abundant; you can find it everywhere. But most hard rock refining is done in China. Our central thesis is if you can find an easier way to crack the rock, get lithium out, and make battery-grade lithium salts, you can change the lithium market. It aligns with the recent push to onshore production of critical minerals in the U.S.”
The team used a liquid reagent, aqueous ammonium fluoride, to dissolve the spodumene rock at temperatures around 200°F. It takes under twelve hours to extract all the lithium and works in stirred plastic tanks, making it more practical and less energy intensive compared to modern techniques. Tests were conducted on 17 types of spodumene samples.
First, the team isolated lithium fluoride before isolating lithium hydroxide and lithium carbonate. Afterward, they went back to the lab to create processes to produce both. Some of these involved adding carbon dioxide or sodium carbonate. In addition, the team isolated aluminum in the rock via high-temperature separation techniques and silica, isolated by precipitation.
Apart from lithium, this process creates byproducts such as smelter-grade alumina for aluminum smelting and cement-ready silica. It valorizes all the elements found in the rock instead of eliminating waste material. Thanks to the closed-loop system, the ammonium fluoride reagent and water can be reused, resulting in nearly no waste. Diluted bicarbonate solutions neutralize any leftover waste to produce sodium fluoride. Even then, MIT’s new approach is better for the environment than metal leaching, which relies on harsh chemicals and produces waste.
MIT says its method may cut lithium production costs from spodumene by over 40%, which could lead to cost parity with lithium extraction from brine water. They also founded a startup called Rock Zero to commercialize the technology, and according to estimates, the costs could reach $5,000 per metric ton. The startup is expected to build a pilot plant by the end of 2026, operating in 2027.
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