“At scale, we consider this would be the lowest-cost means of sourcing lithium on this 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 option 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 enormous 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 compounds.
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 Methods, which makes cement utilizing electrochemistry.
The group was looking for a supply of extremely reactive silica so as to type stronger cement. One option to make reactive supplies, which may bond simply with different supplies, is to take a nonreactive materials, dissolve it, after which enable it to turn into strong in a extra reactive type. It’s not unimaginable to dissolve silicates, however the best-known means is to make use of hydrofluoric acid, an especially 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 manufactured from silica. “I used to be reworking a bathe in Framingham, Massachusetts, about 25 years in the past,” he says. “So after we began this undertaking, I remembered that cup etching cream and thought, ‘What’s in that?’”
The glass etching cream he remembered, which will 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 appropriate situations, it will probably successfully dissolve silicate minerals with out producing hydrofluoric acid within the course of.
This chemistry might be helpful for any silicate minerals—and there are quite a lot of them. However spodumene, the mineral that’s usually 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 group in spodumene’s route.)
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