Lithium has become one of the world’s most important minerals because it is a key ingredient in the rechargeable batteries that power electric vehicles, smartphones, laptops, and energy storage systems.
As demand for batteries continues to grow, so does the need for lithium.
Although countries such as the United States and Australia have large lithium resources, much of the world’s lithium refining still takes place in China.
One reason is that extracting lithium from hard rock is currently expensive, energy-intensive, and generates large amounts of waste.
Now, researchers at MIT and their collaborators have developed a new process that could dramatically change how lithium is produced.
Their method extracts lithium from hard rock at low temperatures, creates almost no waste, and may cost only about half as much as traditional approaches.
The research was published in the journal Science.
Today, extracting lithium from hard rock usually involves heating the rock to temperatures above 1,000 degrees Celsius and then using chemicals to remove the lithium. The process consumes large amounts of energy, and much of the remaining rock is discarded.
The new method takes a very different approach. Instead of using extreme heat, the researchers use a liquid mixture containing water and ammonium fluoride to dissolve the rock at room temperature. This allows them to separate the rock into its valuable components.
The most common lithium-containing mineral, called spodumene, is made mainly of lithium, aluminum, and silica. The researchers found a way to recover all three materials in useful forms. The lithium can be turned into battery-grade lithium carbonate and lithium hydroxide, which are widely used in electric vehicle batteries. The aluminum can be refined into smelter-grade material, while the silica can be used in cement production.
Because every major component of the rock is recovered and sold, very little is wasted.
The idea for the process has an unusual origin. About 25 years ago, MIT professor Yet-Ming Chiang noticed that a glass-etching cream used ammonium fluoride to dissolve glass. Since glass and spodumene both contain large amounts of silica, he wondered whether the same chemistry could be used to break apart lithium-bearing rock.
The concept eventually led to a breakthrough. After separating the minerals, the team also developed a way to recover and reuse the ammonium fluoride and water used in the process. This creates a closed-loop system in which the key chemicals are recycled rather than thrown away.
The researchers successfully tested the method on 17 different spodumene rock samples from around the world, suggesting it could be widely adopted.
Beyond the environmental benefits, the team believes the technology could strengthen domestic lithium production in countries such as the United States and Australia. With global demand for lithium expected to rise sharply over the coming decades, more efficient extraction methods will be essential.
To bring the technology to market, the researchers have launched a startup called Rock Zero. They are now working to scale up the process and believe it could become one of the cheapest and most sustainable ways to produce lithium for the batteries of the future.
Source: KSR.
