Researchers at the Massachusetts Institute of Technology have developed a low-temperature, closed-loop process to extract battery-grade lithium and other valuable materials from hard rock. Traditional hard rock lithium extraction requires heating ore above 1,000 °C and discarding large amounts of waste. The new method dissolves spodumene—the most common lithium-bearing mineral—at room temperature using a water–ammonium fluoride solution. In doing so, it liberates lithium, aluminum and silica without generating a significant waste stream.
The process separates the three main elements into market-ready products. Lithium is recovered as lithium fluoride, lithium hydroxide and lithium carbonate, all key precursors for battery cathodes and electrolytes. Aluminum is isolated as smelter-grade alumina, and the dissolved silica is precipitated into a cement-ready additive. After each extraction step, the reagent and solvent are recovered through the release and reapplication of ammonia gas, allowing them to be reused and reducing waste to near zero.
Based on laboratory cost modeling, the team estimates this closed-loop approach could cut extraction costs by roughly half compared to conventional hard rock methods, bringing it on par with brine-based lithium production. The versatility of the technique was demonstrated across 17 different spodumene sources worldwide, underscoring its broad applicability. A paper detailing the findings was published in Science.
Inspired by the active ingredient in commercial glass-etching cream, the researchers reversed the usual mineral-processing approach by dissolving silica first, rather than treating it as residue. Subsequent bench-scale work refined each material stream to meet industry purity standards through targeted precipitation, carbonation and high-temperature separation steps.
To advance commercialization, the team has formed a spinout, Rock Zero, which is scaling the process at The Engine innovation center. Initial techno-economic assessments suggest the method could support the production of lithium for hundreds of gigawatt-hours of battery capacity while generating co-products that align with global commodity markets.
Funding for the project was provided by the U.S. Department of Energy’s ARPA-E program, the MIT Climate Grant Challenges, and the National Science Foundation. Source: MIT News
