More than half of the world’s lithium comes from minerals. But wringing the critical battery metal from hard-rock ores is energy and chemically intensive and emits three times as much carbon dioxide as getting lithium from salty brines.
A new method to extract lithium from hard-rock minerals promises not only to cut those emissions and waste but also to cut costs by up to 40% (Science 2026, DOI: 10.1126/science.aec4652). Researchers at the Massachusetts Institute of Technology used a simple liquid reagent to dissolve the lithium mineral called spodumene (LiAl(SiO3)2) near room temperature. The process yielded three valuable compounds: lithium carbonate for batteries, alumina for smelters, and silica for cement.
Mines in Australia produce most of the world’s spodumene today, and it is shipped to China for processing into lithium salts; China controls 70% of global lithium refining. Traditional processing involves crushing the ore to separate the spodumene, roasting the spodumene to 1,000 °C, and then using sulfuric acid to leach the lithium. Refining spodumene generates huge volumes of liquid and solid waste and costs two to three times as much as evaporating brines to get lithium salts.
MIT materials scientist and engineer Yet-Ming Chiang and his colleagues stumbled upon their new lithium-extraction process serendipitously. Three years ago, Chiang’s team was looking for a low-cost route to making highly reactive silica for low-carbon cement. The researchers found they could dissolve silicate minerals with aqueous ammonium fluoride, which is used to etch glass. “An aqueous solution turns out to be important. Because while you can use the anhydrous form, when you warm it up, it gives off hydrofluoric acid, which is exactly what we’re trying to avoid,” he says.
When he turned his attention to critical materials extraction, Chiang realized that spodumene was “an interesting silicate mineral to attack in this way.” The researchers heat the ammonium fluoride solution, creating ammonium bifluoride and ammonia gas, which they capture to use later. Ammonium bifluoride reacts with spodumene powder at 60–80 °C to give fluorinated lithium, aluminum, and silicon species.
With a few more chemical reaction steps using the ammonia captured previously and nitric acid, the researchers get silica, alumina, and lithium carbonate. The leftover solution has aqueous ammonium fluoride, which can be reused.
The process extracts over 90% of the lithium in 24 h. And the team showed that it worked on 17 spodumene samples from around the world. The group’s technoeconomic analysis also shows that the process’s cost could compete with lithium produced from the best brine sources. Chiang and his colleagues Camden Hunt and Benjamin A. W. Mowbray have now cofounded a start-up, Rock Zero, to scale up and commercialize the technology.
That large-scale translation might not be straightforward, says Cheng-Lin Liu, a chemical engineer at East China University of Science and Technology. The low energy consumption of the process and its potential to recover aluminum and silicon as marketable coproducts rather than waste is a meaningful innovation, he says. But the process is slow, and the purification steps are complex. “Successful scale-up will depend on whether reaction kinetics can be significantly accelerated and whether the purification challenges can be resolved economically,” Liu says.
Karthish Manthiram, a chemical engineer at the California Institute of Technology, says eliminating high-temperature kilns would make it easier and cheaper to build lithium-refining facilities closer to where the ores are mined, “a paradigm shift from the centralized operations used today,” he says. “Processing at mild temperatures also improves integration with renewable power.”
