Highlights

• REE-FLEX pilot project (2025-2028) brings together CARESTER and SOLVOMET to develop modular solvent extraction technology for separating light and heavy rare earths via nitrate route with flexible input streams.
• The initiative addresses critical bottlenecks in non-Chinese rare earth supply chains, with CARESTER upgrading its Caremag plant to meet Europe's growing demand for permanent magnets in wind and automotive sectors.
• Project represents rare concentration of production-relevant separation expertise in Europe, potentially establishing a design reference for future refining plants and reducing dependence on Chinese rare earth processing dominance.

Rare Earth Exchanges notes the launch of the REE-FLEX pilot project (opens in a new tab), a strategically significant development in global rare earth refining capacity that underscores how scarce true separation expertise remains outside China. The newly launched website for REE-FLEX (Skid Rare Earth Solvent Extraction Pilot Unit in Nitrate Route Designed for Flexible Input Streams) confirms that the project brings together an unusually deep concentration of European rare earth talent: CARESTER (opens in a new tab), a leading French rare earth separator and spinoff of Solvay, and SOLVOMET R&I Centre at KU Leuven (opens in a new tab), one of Europe’s premier hydrometallurgy and circular-processing research hubs.

Funded by EIT RawMaterials (opens in a new tab) under the KAVA 13 Upscaling call (opens in a new tab), REE-FLEX runs from September 2025 through August 2028 and aims to develop and upscale next-generation solvent extraction (SX) technology for separating both light and heavy rare earths via the nitrate route. The technology is designed to handle flexible input streams, including primary ores and recycled materials, addressing one of the hardest technical bottlenecks in non-Chinese rare earth supply chains.

At the core of the project is CARESTER’s proprietary separation chemistry, which will be used to upgrade its Caremag industrial plant, directly targeting Europe’s growing demand for rare-earth permanent magnets in wind energy and automotive applications. SOLVOMET will support the effort by developing real-time analytical monitoring of rare earth concentrations in mixer-settlers and a novel process to split ammonium nitrate waste salts into reusable ammonia and nitric acid, improving both economics and environmental performance.

Rare Earth Exchanges™ has consistently reported that rare earth refining and separation know-how is far more concentrated—and harder to replicate—than mining itself. From that perspective, REE-FLEX is notable not simply as a pilot plant, but as a rare example of elite, production-relevant solvent extraction expertise coalescing in Europe at a moment when export controls on dysprosium and terbium have exposed deep strategic vulnerabilities.

If successful, the modular SX skid developed under REE-FLEX could become a design reference for future rare earth separation plants in Europe and allied markets—representing a small but meaningful step toward breaking China’s long-standing dominance in rare earth refining.

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