A domestic source for a widely used material
A Pacific Northwest National Laboratory (PNNL) reactor could turn seawater into a domestic source of magnesium hydroxide, a widely used material that the United States currently imports in large volumes. The proposal links two existing pressures: reliance on imported industrial inputs and the need to find more varied sources for materials used in manufacturing.
The process may also be adaptable to other minerals, including nickel, giving it potential value as manufacturers look to diversify concentrated supply chains. That possibility is still prospective. The reactor described here produces magnesium hydroxide; wider mineral recovery would require further development and evidence that it works in practice.
China’s processing share raises supply concerns
China accounts for about 85% to 95% of global refined rare earth supply and 85% to 90% of rare earth mining and refining, according to figures cited in the source article. Its refineries also produce 68% of the world’s cobalt, 65% of its nickel and 60% of battery-grade lithium. These figures describe different stages and materials, but together they show how much processing capacity is concentrated in one country.
That concentration leaves industries exposed if supply tightens, prices rise or demand outpaces production. A disruption at a major supplier can matter even when the underlying mineral exists elsewhere: mining and refining capacity are separate parts of the chain, and additional raw material does not automatically replace lost processing. This is more significant than it looks. Supply security depends on where materials can be processed, not only where they can be found.
The International Energy Agency projects that clean energy’s demand for critical minerals could at least double by 2040, and potentially quadruple, depending on how quickly clean energy expands. Electric vehicles and battery storage are expected to drive much of the growth, with lithium demand rising fastest. Those projections indicate pressure on supply chains, though they don't establish which technologies or producers will meet the added demand.
The stakes extend beyond energy companies. A supply disruption could affect manufacturers and slow clean energy projects, while mineral-producing countries are also weighing the economic opportunities. In 2024, UN Secretary-General António Guterres said critical minerals could help developing countries create jobs, diversify economies and increase revenues if managed properly. The qualification matters: access to valuable resources doesn't by itself ensure that the gains reach local economies.
How the seawater process works
PNNL’s co-flow reactor brings seawater and sodium hydroxide together to produce magnesium hydroxide. The lab says the resulting material could serve U.S. industrial demand, and that the process may be paired with desalination facilities. Pairing extraction with an existing seawater operation could give the approach a practical foothold, though the article doesn't establish what changes a desalination plant would need or what those changes would cost.
PNNL analysis estimates that installing the technology at California’s Carlsbad desalination plant could yield as much as 1.16 million pounds (524,000 kilograms) of magnesium hydroxide per day. That would exceed three times the United States’ daily use, according to the analysis. The estimate points to substantial potential at one site, though it doesn't establish how much production would be commercially viable or whether output at that level could be sustained.
Seawater’s relatively consistent chemical composition could help the process scale across locations. “The biggest advantage of seawater is that on average it has reasonably standard chemical composition all around the world,” said Chinmayee Subban, a chemist at PNNL. “That means that we can develop a technology for one location and rapidly scale it to be deployed in many different places.” Consistency could simplify adapting the process, but deployment still depends on conditions at each facility and the economics of operating the equipment there.
PNNL chemical oceanographer Jessica Cross said that a small share of seawater contains large quantities of minerals such as magnesium and lithium, if they can be fully extracted. The reactor described here is focused on magnesium hydroxide; broader extraction of other minerals remains a potential application rather than a demonstrated output. And yet, the wider possibility helps explain why researchers are examining seawater as a resource, even as the first practical case remains narrower.
Scale and economics will determine the impact
The reactor offers a possible route to add domestic production alongside conventional mineral supply. Its projected output at Carlsbad is notable relative to U.S. use, while the prospect of installation at other desalination plants could widen the opportunity. But a projection at one facility doesn't answer whether the approach can compete with existing supply or be repeated at comparable scale.
For industry, the key question is whether the process can deliver consistent output at competitive cost across multiple sites. That means the estimated volume is only one part of the picture; operating costs and the ability to maintain production would shape its value to buyers. If you're working in this space, the distinction between technical potential and dependable commercial supply is the one to watch.
Here's the thing: a domestic source could reduce reliance on imports only to the extent that it can produce material reliably and at a price users will accept. If it can, seawater processing could broaden the sources of materials used in manufacturing and energy storage. For now, the Carlsbad estimate makes the technology’s potential concrete, while commercial performance and expansion will determine its contribution to supply security. A promising route. Not yet a proven substitute.