In a significant development for the mining and energy sectors, engineers have demonstrated a novel, cost-effective, and environmentally friendly method to extract valuable resources, including lithium, from brine. The breakthrough, achieved by a team from the Australian National University (ANU), introduces the world’s first thermal desalination method using thermodiffusion, a process that leverages temperature gradients to drive the migration of dissolved substances.
The study, published in Nature Water, highlights the potential of this approach to address a pressing environmental issue: the vast amounts of brine produced by desalination plants. Currently, over 20,000 desalination plants worldwide discharge approximately 130 million metric tonnes of brine per day, posing significant threats to natural resources, including water and soil. The industry’s pursuit of zero liquid discharge (ZLD) faces substantial challenges, but the ANU team’s findings offer a promising alternative.
Associate Professor Juan Felipe Torres, a mechanical and environmental engineer at ANU and Chief Investigator of the study, explains that thermodiffusion can concentrate brine with higher salinity. “Existing technologies for desalination and brine concentration are well-established, but our thermodiffusion technology offers a promising alternative,” he says. Unlike current desalination methods that require large amounts of electricity and expensive materials, thermodiffusion needs only moderate heat (30–70°C), which can be sourced from sunlight or as a waste product of industrial processes.
Torres emphasizes the efficiency and cost-effectiveness of the new method. “Our thermodiffusive method has been successfully used for water desalination, while reducing energy costs and corrosion issues,” he states. The process can manipulate the salinity of brine concentration solutions without evaporation, preventing water waste. This innovation is particularly relevant for the mining industry, as briny solutions like seawater, salt lakes, and groundwater are crucial sources of minerals such as table salt, magnesium, bromine, calcium, and lithium.
Top lithium suppliers, including Argentina, Chile, and China, primarily recover the critical mineral from brine. Torres envisions that their method could enhance this process. “Our goal is to replace traditional evaporation ponds, a technology that is thousands of years old,” he says. “Instead of using vast amounts of land area and water resources, we can do the job with a much-reduced environmental footprint.”
Dr. Shuqi Xu, ANU Research Fellow and study co-author, highlights the advantages of thermodiffusion technology. “Our research shows how our method is able to manipulate brine concentration for salt production without evaporation,” she says. Future improvements could increase the flow rate and energy efficiency by at least 40 times, making the process even more viable for industrial applications.
The ANU team has co-founded Soret Technologies and partnered with US company Wacomet Water Co to commercialize the technology. “Our vision with Soret Technologies is to revolutionize brine concentration and desalination processes, making them more cost-effective through innovative thermodiffusion technology,” says Torres.
This development could significantly impact the mining sector, particularly in the extraction of lithium, a critical component of batteries and the green energy transition. By offering a more efficient and environmentally friendly method for brine processing, the ANU team’s innovation could reduce the environmental footprint of mining operations and contribute to the sustainable development of critical minerals. The potential for this technology to enhance lithium extraction could also influence global supply chains and the broader adoption of green energy technologies.
As the mining industry continues to face pressure to adopt more sustainable practices, the ANU team’s breakthrough provides a compelling example of how innovation can drive progress. The successful commercialization of this technology could set a new standard for brine processing, inspiring further advancements in the sector and contributing to a more sustainable future.