The demand for lithium has risen sharply due to the growing use of lithium-ion batteries. Although the U.S., Europe, and Australia have significant lithium reserves, China remains the leader in global lithium refining. A major challenge for the U.S. and Australia is extracting lithium from hard rock minerals in a usable form. Currently, this process is energy-intensive and costly, particularly compared to extracting lithium from brine water, which also has environmental concerns. The conventional method involves heating rock to over 1,000 degrees Celsius and applying chemical leaching, discarding the remaining material.<\/p>\n
Researchers from MIT and other institutions have created a low-temperature method to extract lithium from hard rock minerals. This approach uses a liquid reagent to dissolve the rock into battery-grade lithium salts, smelter-grade alumina, and cement-ready silica. The process allows for the recovery and reuse of the solvent and reagent, significantly reducing waste. The new technique is estimated to be half the cost of traditional methods and could compete with brine extraction economically. The findings have been published in Science, and the team is commercializing the technology through an MIT spinout named Rock Zero.<\/p>\n
Camden Hunt, a former project manager at MIT, emphasizes the need to increase global lithium production fourfold by 2040. He notes that refining hard rock lithium is mostly done in China and suggests that easier extraction methods could reshape the market, aligning with efforts to produce critical minerals domestically in the U.S. Contributors to the research include former MIT postdoc Benjamin Mowbray, PhD candidate Kalyn Fuelling, undergraduate Jacqueline Prawira, and others from MIT.<\/p>\n
The research traces its origins to a personal project of Yet-Ming Chiang, who discovered that ammonium fluoride, a component of glass etching cream, could chemically break down spodumene, a common lithium-bearing mineral. This process, using a mixture of water and ammonium fluoride, dissolves silica first, which was a breakthrough in mining. The team successfully dissolved spodumene at room temperature, leading to a closed-loop system that produces valuable materials.<\/p>\n
Mowbray and Hunt, both with chemistry PhDs, focused on refining lithium fluoride, lithium hydroxide, and lithium carbonate from the dissolved spodumene. The process also isolated aluminum using high-temperature separation and silica through precipitation. They ensured the purity of these products for their respective markets, such as battery-grade lithium carbonate and cement additive silica.<\/p>\n
The team developed a method to reuse ammonium fluoride and water in the reaction process. Chiang explains that the process dissolves the rock, releases its elements, and uses ammonia gas to precipitate silica, enabling the recovery of ammonium fluoride. They successfully applied this method to spodumene from 17 sources worldwide, demonstrating its versatility.<\/p>\n
Chiang encouraged the team to assess the commercial viability of their method, considering the global supply of spodumene and the market for co-products. They evaluated costs and resources, concluding that the approach could significantly impact the industry. The researchers have partnered with MIT’s Technology Licensing Office to establish Rock Zero, a company scaling the technology at The Engine.<\/p>\n
Chiang states that their system represents the most energy-efficient and cost-effective method of extracting lithium, not only from hard rock but overall. This innovation aligns with The Climate Project at MIT, aiming to support the energy transition through advanced battery technology.<\/p>\n