Lithium mining is like a contemporary gold rush. The element is the primary ingredient in batteries powering smartphones, electric cars, and even AI. Global demand is surging. Increased production could guide the world toward a more sustainable energy future.
But paradoxically, current extraction methods offset a few of those gains. Lithium mining involves separating the element from brines using toxic chemicals, a process that also pumps out carbon dioxide. This, alongside enormous water and energy costs—as a consequence of extreme temperature requirements—has confined mining to a handful of nations.
To handle these drawbacks, scientists on the Massachusetts Institute of Technology have now developed a low-cost, low-temperature, greener process counting on an abundant resource: Hard rock. Although rocks containing lithium cover large parts of the US, Europe, and Africa, extracting it from them is difficult.
While renovating his bathroom, study creator Yet-Ming Chiang realized a chemical in glass etching cream—which makes glass translucent—could eat away at lithium-rich rocks. His team then designed a recyclable process to extract lithium in addition to two ingredients used to make greener cement and other materials.
“You’ve heard of nose-to-tail eating?” said Chiang in a press release. “We confer with this as nose-to-tail mining.”
Unlike previous methods, the method runs at temperatures below the boiling point of water. All liquid chemicals are almost recyclable and could be reused in multiple rounds of extraction.
“This might establish a low-carbon alternative to hard rock refining, addressing each the surging demand for lithium and the carbon footprint that undermines the sustainability of the energy transition that lithium is supposed to enable,” wrote Gang San Lee and Karthish Manthiram on the California Institute of Technology, who weren’t involved within the study.
A Rock and a Hard Place
The Earth’s crust teems with lithium. Getting it out is the hard part.
Currently, many mining operations depend on brine that naturally leaches lithium over millennia. Later steps purify the lithium right into a battery-ready product. The method relies on large evaporation pools and is restricted to a number of countries, making the resource scarce.
Lithium could, alternatively, be harvested from solid rocks. One ore, spodumene, is full of lithium, roughly 1.5 percent by weight. But liberating it has been a troublesome nut to crack.
Traditionally, miners crush rocks and take away chunks that don’t contain lithium. The rocks are then blasted at temperatures as high as 1,100 degrees Celsius (2,012 degrees Fahrenheit) and showered in a cocktail of dangerous chemicals. The method spews liquid waste into the environment and releases 20 tons of carbon for every ton of lithium.
Researchers are working on more temperate methods.
One in all these is named ball milling. Ore is rotated in a container stuffed with hard balls that mechanically grind the stone right into a effective power. It’s like using a mortar and pestle as an alternative of a blender. But the method takes longer, and lithium is lost along the way in which, leading to lower yields. One other method, called electrochemical leaching, refines the ore at room temperature. But researchers have had mixed success with the method, and it’s tough to scale up. It also produces in numerous waste rock that would, in theory, be harvested for other uses as an alternative being discarded.
Triple Threat
The brand new method popped into Chiang’s mind as he was brainstorming ways to interrupt apart spodumene, a lithium-rich ore with high amounts of silica—the primary ingredient in glass.
Dissolving silica to get to lithium requires hydrofluoric acid, a highly toxic chemical. But glass etching cream also eats away at silica with ammonium fluoride. Tubes of the mild acid can be found in home improvement stores, and it really works at room temperature. Why not give it a try?
By mixing ammonium fluoride with water, the team showed they might completely dissolve spodumene at temperatures below 100 degrees Celsius without releasing toxic fumes. They only needed to repeatedly stir the ore in an easy plastic tank. The method yielded several kinds of lithium salt with 99 percent purity. In early experiments, extraction took several days, however the team has since cut the time to under 12 hours.
“Dissolving silica is the hard part in mining,” said study creator Benjamin Mowbray. “The following query was how will we apply it to impactful mineral processing problems?”
Together with lithium, spodumene is jam-packed with two often discarded ingredients: Alumina, which after smelting makes aluminum, and silica, which could be directly used as a sustainable ingredient in greener cement. The brand new process can separate out each materials, and the team vetted the resulting products, including strength testing cubes of fabricated cement.
“First our goal was to supply these products, then there have been additional steps of characterizing their purity and properties and ensuring our products met the specifications for goal markets,” said Mowbray.
“If any product didn’t meet the goal specs, you’d find yourself with a waste stream.”
With a number of chemical tweaks, the team showed the acid may very well be regenerated and reused a minimum of five times. The team successfully processed 17 spodumene ores sourced from all over the world, suggesting the tactic may very well be broadly applicable.
They’ve also spun the work right into a startup, Rock Zero, and aim to scale it. If the acid could be recycled with near-perfect efficiency, the team estimates the method would cut costs over 40 percent compared to standard hard-rock extraction, making it competitive with brine operations.
Its simplicity could also reshape where lithium gets produced. In 2024, roughly 74 percent of world lithium output got here from just three countries: China, Australia, and Chile. By eliminating the necessity for extreme heat and large waste-treatment plants, the method may very well be easier to implement, especially in countries wealthy in spodumene but lacking the capital for infrastructure.
That opens the door to a network of smaller refineries built closer to the mines themselves, reducing transportation costs and supply-chain bottlenecks. Because the method can be far less energy intensive, it may very well be powered by solar and wind, further shrinking its environmental impact.
The technology is also adapted to recuperate other worthwhile metals hidden inside mineral ores. One candidate is beryllium, a light-weight but extremely stiff and stable metal utilized in satellites and the James Webb Space Telescope’s mirrors. Current manufacturing processes often generate toxic dust and fumes linked to serious lung inflammation. A cleaner extraction route could make it safer and cheaper to supply.
As for Rock Zero, going up against established lithium giants is like David and Goliath. They’ll also should contend with global market volatility and increasing competitiveness of sodium-ion batteries and other alternative battery chemistries.
However the team is unfazed. “We consider this approach is the lowest-energy, lowest-cost way of getting lithium not only out of hard rock, but period,” said Chiang. “That’s what’s motivating us to scale this.”