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Pacific Northwest National Laboratory researchers outline methods to extract critical minerals from seawater
Summary
Scientists at the Pacific Northwest National Laboratory described laboratory research showing how desalination-coupled reactors and algae-based processing could extract magnesium, lithium and rare earth elements from seawater, which the presenters said could be a long-term domestic supply.
Researchers at the Pacific Northwest National Laboratory (PNNL) described laboratory work showing multiple methods to extract critical minerals from seawater and brines, saying the ocean could be a long‑term domestic source for some elements.
"A tiny fraction of the ocean, just point 1%, contains enough rare earth metals to meet The US needs for 50000 years," said Joanna Wendell, a science writer at PNNL. She also recited laboratory estimates for lithium and magnesium, saying "For lithium, enough for 1000000 years. And magnesium, enough for 1000000000 years." Wendell framed the research as a potential way to secure domestic supply chains for materials used in electronics and clean‑energy technologies.
"Seawater is abundant, but the minerals we wanna extract are fairly dilute," said Chinmay Suben, a chemist who described the technical constraints. He said extracting those trace minerals requires moving and processing large volumes of water, which raises energy and engineering challenges.
To limit operational problems at desalination plants, Suben said PNNL researchers have developed low‑cost, efficient reactors that "can integrate with desalination to recover those valuable magnesium compounds at very high purities from seawater before they can degrade the desalination membranes." That approach, he said, could both protect membranes and capture magnesium as a usable product.
Research botanist Scott Edmondson described a separate biological route: "Marine algae, also known as seaweeds, can biologically concentrate some of the rare earth elements millions of times more than levels found in seawater," he said, adding that some species can grow in waste brines and that minerals captured by seaweeds could be removed by physical or chemical processing. Edmondson suggested future work could focus on breeding or engineering strains to target specific critical minerals.
Wendell said the researchers believe these methods could be deployed responsibly on relatively near timeframes and emphasized that, unlike finite terrestrial ore bodies, seawater represents a broadly distributed and long‑term resource for certain elements. The presenters stressed that significant engineering, energy‑use, environmental impact assessment and pilot testing will be required before commercial deployment.
Next steps identified in the presentation include continued laboratory development, integration testing with desalination processes, and investigations of biological scalability and downstream processing for algae‑derived concentrates.
