Researchers at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) are developing technologies to extract valuable minerals directly from seawater, opening a new path to supplying materials needed for batteries, electronics, clean energy systems, and electric vehicles.
By combining advanced chemistry with existing coastal infrastructure, the team aims to turn the world’s oceans into a long-term source of essential industrial materials.
The demand for minerals such as lithium, magnesium, nickel, and rare earth elements continues to grow as countries expand electric mobility, renewable energy, and digital technologies. Traditional mining alone may struggle to keep pace while facing environmental, economic, and geopolitical challenges. That has pushed researchers to explore unconventional resources that are widely available and easier to access.
Seawater appears to be one of the largest untapped mineral reservoirs on Earth. Scientists estimate that even a tiny fraction of the world’s oceans contains enough dissolved critical minerals to support human demand for many thousands of years. The challenge is finding practical ways to recover those materials without using excessive energy or creating unnecessary waste.
Seawater Holds Opportunity
Researchers at PNNL believe the ocean offers more than just an alternative source of minerals. Because seawater has a relatively consistent chemical composition across different regions, technologies designed for one coastline can potentially operate in many others with only limited adjustments.
Jessica Cross, a chemical oceanographer at PNNL, said extracting minerals from only 0.1 percent of seawater could provide enough magnesium, lithium, and other critical materials to satisfy global demand for more than 50,000 years. That estimate highlights the enormous scale of the resource available beneath the ocean’s surface.
The difficulty lies in concentration rather than availability. Chinmayee Subban, who leads research on ocean-based chemical technologies at PNNL, explained that while seawater contains abundant magnesium, other valuable minerals occur only in trace amounts. Processing enough water to recover those elements efficiently remains the central engineering challenge.
An Olympic-sized swimming pool illustrates the difference clearly. It contains nearly 2,980 kilograms of magnesium, about 0.42 kilograms of lithium, and less than 1 gram of nickel. Recovering those smaller quantities requires highly selective technologies that minimize energy use while maximizing mineral recovery.
Researchers have already demonstrated recovery of magnesium, lithium, nickel, platinum-group metals, and rare earth elements using seawater and seawater-derived chemicals. These materials support industries ranging from semiconductor manufacturing and consumer electronics to renewable energy and transportation.
Simpler Extraction Process
Magnesium extraction from seawater has historical roots in the US. During and after World War II, companies produced magnesium from seawater using a lengthy industrial process involving several chemical reactions before imports gradually replaced domestic production.
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PNNL researchers redesigned that workflow to make it faster and more efficient. Their system passes seawater alongside a sodium hydroxide solution inside a co-flow reactor, allowing high-purity magnesium hydroxide to form naturally where the liquids meet.
The process eliminates several steps found in older production methods. Researchers stop after producing magnesium hydroxide instead of converting it into magnesium metal because the compound itself already serves important industrial markets and is largely imported into the United States.
The laboratory plans to deploy the technology at PNNL-Sequim, the Department of Energy’s marine science laboratory. The research team has also filed a patent covering the reactor system.
Scaling production remains an important part of the project. Environmental engineer Brooke Marten studied existing desalination facilities and found they offer an efficient platform, as they already move enormous volumes of seawater through treatment systems every day.
The desalination plant in Carlsbad, California, processes around 108 million gallons of seawater daily. Researchers estimate that complete magnesium recovery at that scale would generate roughly 524,000 kilograms of magnesium hydroxide every day, exceeding current US demand several times over.
The reactor system was designed with modular construction in mind. Additional units can be installed as demand increases, allowing operators to expand production without building entirely new processing facilities.
Every Drop Counts
The project focuses on recovering value from every stage of seawater processing rather than extracting only one material. After magnesium removal, desalination systems continue producing freshwater while leaving behind concentrated brine.
Researchers process this brine using bipolar membrane electrodialysis(BPMED). The technology uses electricity and specialized membranes to split saltwater into acid and alkaline solutions that support additional mineral recovery processes.
One surprising result emerged when scientists tested the acid produced by BPMED. Instead of treating it as a waste product, they used it to extract nickel from olivine, a mineral that naturally contains nickel.
The BPMED-generated acid extracted 37 percent more nickel than commercially available hydrochloric acid. That finding demonstrates how one process can strengthen another while reducing waste and improving overall efficiency.
Researchers say this integrated approach is central to making seawater mineral extraction economically viable. Every useful product created from the same water stream helps lower operating costs and improve the overall system’s value.
Seaweed Joins Mission
Marine plants have become another important part of the research effort. Scientists discovered that some seaweed species naturally absorb dissolved minerals from seawater and store them at concentrations far higher than those found in the surrounding ocean.
Research botanist Scott Edmundson said certain critical minerals become concentrated inside seaweed at levels up to one million times greater than in seawater. That natural process effectively turns seaweed into a biological collection system for valuable elements.
Researchers are identifying which seaweed species most effectively accumulate specific minerals and are studying cultivation techniques that increase mineral content. The harvested biomass is then processed by hydrothermal liquefaction, which converts wet plant material into fuels, fertilizers, industrial chemicals, and other useful products, along with recovered minerals.
The team also found another connection between its technologies. Waste streams produced during BPMED produce slightly acidic seawater, and previous studies have shown that some seaweed species grow faster under these conditions. Faster growth could improve both biomass production and mineral recovery within a single integrated operation.
As governments and industries search for secure supplies of critical minerals, seawater is emerging as more than an environmental curiosity. By combining advanced chemistry, desalination infrastructure, and marine biology into a single, integrated system, PNNL researchers are laying the foundation for a new approach to mineral production that could support future energy, technology, and manufacturing industries worldwide.
