CRITICAL MINERALSLow-Cost Technique to Get Lithium Out of Rocks
Demand for lithium has surged in recent years as lithium-ion batteries power increasingly more of our world. A new low-temperature process could unlock cleaner lithium from America’s abundant hard rock while minimizing waste.
Demand for lithium has surged in recent years as lithium-ion batteries power increasingly more of our world. And yet, even as places like the U.S., Europe, and Australia have abundant lithium resources within their borders, China dominates global lithium refining. The biggest hurdle to tapping into the U.S. and Australia’s lithium is getting it out of hard rock minerals in a form that is useful.
Extracting lithium from hard rock today is an energy- and waste-intensive process that is often far more expensive than getting lithium from brine water, which also has major environmental drawbacks. Currently, lithium hard rock extraction involves baking the rock at over 1,000 Celsius and chemically leaching it to extract lithium. The rest of the rock is discarded.
Now, a team of researchers from MIT and elsewhere has developed a low-temperature process for extracting battery-grade lithium from the most common type of lithium-bearing mineral. The process uses a liquid reagent to dissolve the rock into the useful forms of its constituent parts: not just battery-ready lithium salts, but also smelter-grade alumina and cement-ready silica. After the minerals are extracted, the solvent and reagent can be recovered and used again so waste levels approach zero.
The researchers estimate the closed-loop process is half the cost of traditional lithium hard rock extraction and could make it cost-competitive with extracting lithium from brine water.
A paper describing the process was published today in Science. The researchers have already begun commercializing the technology through an MIT spinout, Rock Zero.
“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.”
Joining Hunt on the paper are former MIT postdoc Benjamin Mowbray; PhD candidate Kalyn Fuelling; MIT undergraduate Jacqueline Prawira; Khashayar Jafari, a former senior research scientist at the MIT green cement spinout Sublime Systems; and Yet-Ming Chiang, MIT’s Kyocera Professor of Materials Science and Engineering.
