For all his contributions to clean energy technology, lithium It is a resource that is difficult to obtain and is not environmentally friendly. So scientists looked for more sustainable ways to meet the growing demand for lithium, including a new proposal for a safer, cheaper strategy to tap the hard rock that contains the precious element.
The new process is detailed in a new study has been published A mineral named today in the journal Science separates chemically spodumene converted into lithium, aluminum and silicon, which are then separated and refined for the respective industrial purposes. Unlike traditional methods, the latest alternative is a low-temperature, acid-free approach that extracts the most valuable products from spodumene’s primary mineral components.
Deployed on a large scale, it would be “the lowest-cost way to get lithium from any natural resource.” Ming Chiang againstudy co-author and Kyocera Professor of Materials Science and Engineering at the Massachusetts Institute of Technology (MIT), told Gizmodo.
Lithium lore
according to MIT Climate Portallithium is obtained either by evaporating brine pools or by mining hard rock. In the first, brine is pumped from underground deposits and released into pools to evaporate, leaving lithium and other elements behind. Hard rock mines “look more traditional” and use heavy machinery to dig and crush the spodumene. Both types of mining use a lot of water and have fairly large carbon footprints.
The global lithium industry also faces significantly higher supply and geopolitical risks, a report International Energy Agency (IEA) notes. The report estimates the lithium industry’s “capacity to respond to supply disruptions” at a paltry 3%, while 57% of lithium refining will depend on China by 2030.
Find an alternative
Chiang explained to Gizmodo that the new process uses ammonium fluoride to “safely dissolve the silicate matrix into the solid rock, thereby liberating aluminum as well as lithium.” This eliminates the need to “roast” the spodumene before acid washing, a step that creates carbon dioxide emissions.
The team tested their method on 17 different spodumene concentrate sources and successfully recovered more than 95% of the lithium stored in the mineral. The process is also a “closed-loop” approach that recycles and reuses the chemical reagent, unlike conventional methods that generate different wastes at each step.
The trick was to reverse familiar processes in hydrometallurgy — extracting metals from ores — where “silicate is usually the most resistant to dissolution and the last component left,” Chiang said. “Here, we turn it on its head and remove the silicate first. It makes me wonder what other minerals we can process this way.”
Concept to reality
This could bring significant changes to the lithium industry, California Institute of Technology (Caltech) chemical engineers Gangsan Lee and Karthish Manthiram wrote in an accompanying note. Perspective article.
For example, the closed-loop process eliminates the need for large-scale waste treatment plants, which increase infrastructure costs. Because of its low temperature, it is easier to “integrate with renewable energy”, which is important as “large lithium ore deposits are geographically coincident with abundant solar and wind resources”.
These benefits significantly lower the barriers to lithium mining — addressing “both the growing demand for lithium and the unsustainable carbon footprint of the energy transition that lithium is meant to enable,” the Caltech engineers added.
All that said, Chiang told Gizmodo that the process still needs to be tested on an industrial scale. The research team established a spinout, Rock Zerofocus on starting pilot demonstrations for the new method.
“Mining is important to technology and therefore to society, but is viewed negatively by much of the public as a destructive, polluting industry, sometimes with good reason,” he said. “We hope to help change that perception by showing that there are cleaner, more sustainable ways to do it.”
