USA Rare Earth and France’s Carester are partnering on rare earth element projects in the US and France in an effort to catch up to Chinese firms, which control the industry.
USA Rare Earth says it will take a 12.5% stake in Carester, a specialist in complex rare earth separation techniques. Carestar will use its expertise to help the 7-year-old US firm scale up a separation process it has been developing at a facility in Colorado. The European investment firm InfraVia Capital will invest an equal amount in Carester.
For Carester, the investment will help finance a commercial-scale rare earth separation plant in southern France that the firm plans to open later this year. A USA Rare Earth subsidiary is building a facility in the same region to turn rare earth oxides from Carester into pure metals. The partnership will also give Carester ore containing heavy rare earths from a mine that USA Rare Earth hopes to open in Texas by 2028.
Today, almost all rare earth ore is separated into oxides in China using a solvent extraction method. Chinese firms also produce nearly all rare earth magnets, which are used in electric motors, missiles, and other high-tech products.
Over the past year, China has enacted measures to temporarily slow exports of rare earth products, thus causing major disruptions for carmakers in the US and Europe, according to a new report from the International Energy Agency. The agency estimates that it will cost $60 billion to build a rare earth supply chain outside China capable of meeting expected non-Chinese demand for magnets by 2035.
As the technology rivalry between the US and China has intensified, the US government has started funneling money into the rare earth industry. Since 2022, the US has offered Lynas Rare Earths more than $250 million in grants to help the firm open a rare earth separation facility in Texas. In August 2025, the US bought a $400 million stake in MP Materials, which mines rare earth ore in California and aims to make magnets in the US. Earlier this year, the Department of Commerce said it plans to loan USA Rare Earth $1.3 billion for its planned mine and magnet manufacturing facilities.
The investments to date won’t be enough to put these firms on the same footing as Chinese leaders. Lynas and MP are separating light rare earths into oxides but at far lower volumes than Chinese facilities. Lynas is only beginning to produce heavy rare earth oxides.
While most US and European companies lack rare earth separation and processing expertise, Carester’s team has decades of experience. The firm was founded in 2019 by engineers from Solvay, which was previously a world leader in rare earth separation.
That makes Carester a strong partner for inexperienced firms trying to break into the rare earth industry, says David Merriman, research director at the minerals intelligence firm Project Blue.
“Carester has certainly become a bit of a shining light in rare earth processing expertise outside of the Chinese market,” Merriman says. “A lot of developers can only take their rare earth products so far.”
In addition to USA Rare Earth, Carester is assisting Solvay, Brazilian Rare Earths, and Torngat Metals with rare earth separation technologies.
Matt Blois is a food, ag, and cleantech reporter at C&EN.
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