Khaberni - Researchers at Columbia University's School of Engineering developed a new and rapid technique for extracting lithium directly from underground saline solutions, using a temperature-sensitive solvent, bypassing the large evaporation ponds that can take years and deplete precious water resources.
Researchers believe this method will be effective with low-quality lithium sources, which current technologies struggle to exploit; thus, it is expected to help solve one of the most environmentally polluting issues of clean energy.
Challenges of Lithium Extraction
Global demand for lithium is increasing significantly with the intensification of the electric car industry and the construction of larger battery systems to support wind and solar energy, yet lithium production remains a slow and environmentally costly process.
Dr. Ngai Yin Yip, an associate professor of Earth and Environmental Engineering at Columbia University, told Jazeera Net: "Lithium used in batteries is currently mainly produced from two types of sources: hard rock minerals and lithium-rich saline solutions."
She adds: "In hard rock mining, minerals containing lithium are extracted, then crushed, processed, and chemically converted into lithium products. In saline solution-based production, salty water rich in lithium is brought to the surface and typically concentrated through large evaporation ponds before being chemically processed to produce lithium carbonate or lithium hydroxide."
Ngai adds: "The traditional saline solution method is widely used, but it is slow, requires extensive land areas, and heavily depends on suitable climate conditions, particularly dry environments where evaporation is effective, which are less suitable for many emerging lithium sources, such as geothermal brines and oilfield solutions, where lithium may exist in relatively low concentrations and mixed with substantially higher amounts of sodium, potassium, calcium, magnesium, and other ions."
According to Ngai, the main challenge is the rapidly increasing demand for lithium due to the spread of electric vehicles and energy storage technologies, although current production methods are not always fast, efficient, or environmentally ideal.
Many reports have indicated that traditional lithium production, based on evaporation, takes a long time, requires vast lands, and may consume or damage water resources in sensitive areas.
The researcher adds: "For this reason, there is significant interest in direct lithium extraction technologies, which can selectively remove lithium from saline solutions without relying on large evaporation ponds."
A New Method
According to the research team, the new method demonstrated superior selectivity during tests. It extracted lithium at rates up to ten times higher than sodium and twelve times higher than potassium. It also removed magnesium, one of the most common contaminants in lithium saline solutions, through a chemical precipitation process that separates unwanted materials.
Regarding this, Ngai, in her statements to Jazeera Net, said: "Our method is called 'selective extraction with a switchable solvent' and uses a special type of liquid solvent which changes behavior with temperature. At a low temperature, the solvent can absorb dissolved salts and some water from the saline solution."
She adds: "Importantly, it shows a preference for extracting lithium over other common ions such as sodium and potassium. After extracting the lithium, when we slightly heat the solvent"
According to the study, at a higher temperature, the solvent becomes less compatible with the salts and water, releasing a small stream of lithium-rich water, and the solvent can then be reused.
Ngai states: "Simply put, the solvent acts like a temperature-controlled conveyor; it absorbs lithium from the saline solution at one temperature and then releases a stream of purer lithium at another temperature. Thus, our method differs from many traditional solvent extraction methods as it does not rely on chelating chemicals directly linked to lithium and doesn't require a chemical extraction agent to release the lithium."
She adds: "Instead, the separation depends on the solvent's affinity for water and ions, which changes with temperature. Moreover, in our study, we demonstrated that this method can preferentially extract lithium over sodium and potassium, even when the concentration of lithium is much lower than the competing ions, proving the method's effectiveness using a simulated geothermal saline solution from Salton Lake, and we showed the possibility of reusing the solvent for several cycles."
