Thanks to a recent breakthrough in understanding the chemistry of lithium brine evaporation, an incredible discovery was made. As just one example, we highlight a study conducted in the Salar de Uyuni, the world’s largest salt pan, located in Bolivia’s central Andes Mountains. Roughly 40% of the world’s lithium production originates from salars, large salt pans. This finding is key to the future of lithium extraction and sustainable lithium production.
Avner Vengosh, a faculty member at Duke University’s Nicholas School of the Environment, and now a distinguished professor of public policy at Duke, led the study. For the first time, researchers were able to show from a chemical perspective how boron affects chemical transformations in evaporating lithium-rich brines. This finding has the potential to reform technologies for lithium extraction and inform strategies for sustainable management of such critical resources.
The Role of Boron in Lithium Brines
According to the study, bulking showed how important boron is. It occurs in natural brines in various forms, including boric acid and borates. These compounds markedly alter the chemical speciation and pH of lithium-rich brines. As evaporation progresses in the salt pans, ambient boron concentration grows until the boric acid begins to decompose.
The resulting breakdown of organic material produces hydrogen ions that further decrease the pH of the brine. Gordon Williams, the lead author of the study and a Ph.D. student in Vengosh’s lab, explains, “Through a chain of geochemical reactions, the carbonate alkalinity is diminished in the brine from the Salar de Uyuni, while boron alkalinity becomes predominant.”
The research team went through a detailed review. Their work combined data from more than 300 samples of lithium-rich brine from across these varied salt pans in Chile, Argentina, Bolivia and the Tibetan Plateau. This unique dataset supports a deeper understanding of the role boron plays in mining and lithium extraction technologies around the globe.
Insights from Global Lithium Brines
These recent findings show that boron plays a crucial role in the Salar de Uyuni. It’s an essential player in multiple lithium-rich hotspots across the globe. The integration of chemical analysis with geochemical modeling enabled researchers to quantify different molecular structures of boron and their contributions to alkalinity in these brines.
Paz Nativ, a co-author of the study, stated, “The integration of the chemical analysis with geochemical modeling helped us to quantify the different molecular structures of boron that contribute to alkalinity in these lithium brines.” This monovalent approach has moved us further into developing a clearer picture of how boron interacts with other elements in brines.
Gordon Williams further elaborated on their findings: “In addition to the new data we generated, we compiled a geochemical database of lithium brines from around the world and consistently found that boron is often the predominant component in brine alkalinity and controls brine pH, reinforcing the results from the Salar de Uyuni in Bolivia.”
A Unique Geochemical Landscape
This research is more than mere academic interest. It offers concrete applications for lithium extraction processes as well as strengthening environmental governance. Vengosh commented on the uniqueness of their findings: “We discovered that the pH of brines in these regions is almost entirely driven by boron, unlike seawater and other common saline waters. This is a totally different geochemical landscape, like studying an extraterrestrial planet.”
This innovative study highlights the intricate interaction between many factors in brine chemistry. The need for lithium is rapidly increasing as it is an indispensable component in batteries and other renewable energy technologies. Understanding the chemistry involved with lithium is more important than ever.
