US Seawater Tech Offers Path to Cut China's Mineral Monopoly
A new US reactor technology that extracts critical minerals from seawater could help Washington break Beijing's stranglehold on the global supply chain as clean energy demand surges.
Scientists at the Pacific Northwest National Laboratory (PNNL) have developed a co-flow reactor capable of extracting high-purity magnesium hydroxide from seawater. The technology offers a potential pathway for the United States to diversify its critical mineral supply away from China, which currently dominates the global market. Researchers believe the system could eventually be adapted to harvest other vital materials like nickel.
Beijing controls 85% to 90% of the world’s rare earth mine-to-metal refining, alongside 68% of cobalt, 65% of nickel, and 60% of battery-grade lithium production. This concentration poses a significant financial and operational risk to Western manufacturers and the broader energy transition. “If producers of these substances decide to restrict access to their customers as a political lever, if prices shoot up, or if more industries develop an appetite for them and eat into the supply,” Vox reports, “companies could go bankrupt and efforts to limit climate change could slow down.”
The need for alternative supply sources is becoming urgent as global demand accelerates. The International Energy Agency projects that demand for clean energy minerals will at least double, and potentially quadruple, by 2040. This surge is largely driven by electric vehicle manufacturing and battery storage, a trajectory recently accelerated by the closure of the Strait of Hormuz. “A world powered by renewables is a world hungry for critical minerals,” UN Secretary-General António Guterres said at a Panel on Critical Energy Transition Minerals in 2024.
The PNNL system works by cycling seawater and sodium hydroxide together to precipitate magnesium hydroxide. While the US currently imports large volumes of the compound, integrating this reactor with existing desalination infrastructure could immediately alter the domestic supply picture. Analysis indicates that installing the technology at California’s Carlsbad desalination facility could yield 1.16 million pounds of magnesium hydroxide daily, more than triple current US daily consumption.
The ocean represents a virtually untapped reserve for these materials. “Just 0.1 percent of seawater contains enough critical minerals like magnesium and lithium, if we can fully extract them, to meet humanity’s needs for the next 50,000 years or more,” Jessica Cross, a chemical oceanographer at PNNL, said in a recent press release.
Replicating the technology across different markets would be straightforward because ocean chemistry is consistent globally. “The biggest advantage of seawater is that on average it has reasonably standard chemical composition all around the world,” explained Chinmayee Subban, PhD, 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.”
