“At scale, we imagine this would be the lowest-cost approach of sourcing lithium on the earth,” says But-Ming Chiang, one of many examine authors, who’s an MIT professor and a serial entrepreneur behind local weather tech firms together with Kind Vitality and Addis Vitality.
Probably the most economical solution to get lithium at present is to extract it from brine, salty water that’s pulled the steel out of rock over the course of millennia. However this method is geographically restricted and at present requires huge tracts of land for large evaporation swimming pools. The extra frequent tactic is hard-rock mining, the place massive our bodies of ore are blasted aside, cooked at excessive temperatures, and processed utilizing harmful chemical substances.
The researchers’ new technique makes use of a weak acid to dissolve usually nonreactive silicate minerals. That frees not solely the lithium but in addition 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 Programs, which makes cement utilizing electrochemistry.
The workforce was looking for a supply of extremely reactive silica with a view to type stronger cement. One solution to make reactive supplies, which might bond simply with different supplies, is to take a nonreactive materials, dissolve it, after which permit it to develop into stable in a extra reactive type. It’s not unattainable to dissolve silicates, however the best-known approach is to make use of hydrofluoric acid, an especially harmful chemical. Different fluorine-containing chemical substances are candidates too, however some will produce hydrofluoric acid as a facet product throughout reactions.
Chiang drew inspiration from a earlier residence renovation mission involving glass, which is manufactured from silica. “I used to be transforming a bathe in Framingham, Massachusetts, about 25 years in the past,” he says. “So after we began this mission, I remembered that cup etching cream and thought, ‘What’s in that?’”
The glass etching cream he remembered, which may be discovered on cabinets at any craft or residence enchancment retailer, makes use of ammonium fluoride, a weak acid. And the MIT researchers found that in the best situations, it could 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 lots of them. However spodumene, the mineral that’s typically mined for lithium, turned a primary first goal. (Chiang says a suggestion from Doug Wicks, one of many firm’s advisors and a former ARPA-E official, pointed the workforce in spodumene’s path.)
