“At scale, we imagine this would be the lowest-cost manner of sourcing lithium on the planet,” says But-Ming Chiang, one of many research authors, who’s an MIT professor and a serial entrepreneur behind local weather tech corporations together with Kind Power and Addis Power.
Essentially the most economical solution to get lithium presently is to extract it from brine, salty water that’s pulled the metallic out of rock over the course of millennia. However this method is geographically restricted and presently requires huge tracts of land for large evaporation swimming pools. The extra frequent tactic is hard-rock mining, the place giant our bodies of ore are blasted aside, cooked at excessive temperatures, and processed utilizing harmful chemical compounds.
The researchers’ new methodology makes use of a weak acid to dissolve sometimes nonreactive silicate minerals. That frees not solely the lithium but additionally different helpful supplies, together with alumina and silica.
The origin story for this analysis, and the ensuing firm, got here from one other startup based by Chiang, Chic Methods, which makes cement utilizing electrochemistry.
The group was looking for a supply of extremely reactive silica with the intention to type stronger cement. One solution to make reactive supplies, which may bond simply with different supplies, is to take a nonreactive materials, dissolve it, after which permit it to change into strong in a extra reactive type. It’s not not possible to dissolve silicates, however the best-known manner is to make use of hydrofluoric acid, a particularly harmful chemical. Different fluorine-containing chemical compounds are candidates too, however some will produce hydrofluoric acid as a aspect product throughout reactions.
Chiang drew inspiration from a earlier dwelling renovation undertaking involving glass, which is product of silica. “I used to be transforming a bathe in Framingham, Massachusetts, about 25 years in the past,” he says. “So once we began this undertaking, I remembered that cup etching cream and thought, ‘What’s in that?’”
The glass etching cream he remembered, which might be discovered on cabinets at any craft or dwelling enchancment retailer, makes use of ammonium fluoride, a weak acid. And the MIT researchers found that in the precise circumstances, it may possibly successfully dissolve silicate minerals with out producing hydrofluoric acid within the course of.
This chemistry may very well be helpful for any silicate minerals—and there are a variety of them. However spodumene, the mineral that’s typically mined for lithium, turned a major first goal. (Chiang says a suggestion from Doug Wicks, one of many firm’s advisors and a former ARPA-E official, pointed the group in spodumene’s path.)
