Rare Earth and Critical Mineral Separation Plants

Separation plants are among the most technically complex and strategically significant facilities in the critical minerals value chain. For rare earth elements in particular, the separation stage, where a mixed rare earth concentrate or solution is divided into individual high-purity oxides such as neodymium oxide, praseodymium oxide, dysprosium oxide, and terbium oxide, represents the most concentrated and difficult-to-replicate processing bottleneck. China controls over 90 percent of global rare earth separation capacity, and building competitive facilities outside China has proven to be one of the most formidable challenges in the effort to diversify critical mineral supply chains.

The Solvent Extraction Process

Rare earth separation relies primarily on solvent extraction, a hydrometallurgical process that exploits subtle differences in the chemical properties of adjacent rare earth elements to separate them from each other in solution. The process involves passing aqueous solutions containing dissolved rare earth ions through a series of mixer-settler units where they contact organic solvents containing selective extractants. Because rare earth elements are chemically similar, achieving the high purities required for magnet-grade neodymium or phosphor-grade europium requires hundreds of individual extraction stages, generating large volumes of chemical waste and consuming significant quantities of acids, bases, and organic solvents. The complexity, waste generation, and know-how requirements of solvent extraction explain why so few companies have successfully operated commercial-scale rare earth separation plants outside China. For a detailed technical overview, see rare earth separation in our supply chain section.

Lynas Rare Earths: The Non-Chinese Benchmark

Lynas Rare Earths operates the most significant rare earth separation facility outside China at its plant in Kuantan, Pahang, Malaysia. The facility processes mixed rare earth carbonate from Lynas' Mount Weld mine in Western Australia through cracking, leaching, and multi-stage solvent extraction to produce separated NdPr (neodymium-praseodymium) oxide, lanthanum, cerium, and other rare earth products. Lynas is the world's second-largest rare earth producer after Chinese state-owned enterprises and has been the primary non-Chinese source of magnet-grade rare earth oxides for Japanese and other allied-nation magnet manufacturers. The company is expanding its operations with a new cracking and leaching plant at Kalgoorlie in Western Australia, which will reduce the volume of radioactive waste shipped to Malaysia, and a rare earth processing facility at the U.S. Department of Defense-funded site in Seadrift, Texas.

North American Separation Projects

Several separation plant projects are advancing in North America with government support. MP Materials, which operates the Mountain Pass mine in California, is developing separation capability at the mine site to process its mixed rare earth concentrate into individual oxides domestically rather than shipping it to China for separation, as has historically been the practice. The company has received funding from the U.S. Department of Defense to support this effort. Energy Fuels is producing a mixed rare earth carbonate from monazite sand at its White Mesa mill in Utah and shipping it to Neo Performance Materials' separation facility in Estonia, with plans to develop domestic separation capacity. Ucore Rare Metals is developing the Alaska Strategic Metals Complex, which aims to use a proprietary rapid solvent extraction technology called RapidSX to separate rare earths and other critical minerals at a facility in Louisiana.

Australian and European Projects

Australia hosts several separation plant projects that aim to add integrated mine-to-oxide capabilities. Iluka Resources is constructing a rare earth refinery at Eneabba in Western Australia, supported by a critical minerals loan from the Australian government. The facility will process stockpiled mineral sands concentrate into separated rare earth oxides. Arafura Rare Earths plans to build a separation plant as part of its integrated Nolans project in the Northern Territory. In Europe, the rare earth separation landscape is less developed, but projects are emerging. Less Common Metals in the United Kingdom has separation capabilities, and Solvay's La Rochelle facility in France has historically processed rare earth concentrates, though at limited scale. The European Union's Critical Raw Materials Act has identified rare earth separation as a strategic priority and is channeling funding toward building European capacity.

Beyond Rare Earths: Other Separation Technologies

While rare earth separation attracts the most attention, separation processes are also critical for other mineral systems. Platinum group metal refineries use complex sequential precipitation and solvent extraction circuits to separate platinum, palladium, rhodium, iridium, ruthenium, and osmium from each other. Nickel-cobalt separation is achieved through various hydrometallurgical routes including selective precipitation, solvent extraction, and ion exchange. Lithium separation from brine solutions using direct lithium extraction (DLE) technologies, including adsorption, ion exchange, and membrane-based systems, represents an emerging class of separation technology that could transform lithium production by enabling extraction from lower-grade brines with higher recovery rates and smaller environmental footprints than conventional evaporation ponds.

Technological Innovation and Outlook

Innovation in separation technology is essential for breaking the processing bottleneck. Continuous ion exchange chromatography, advanced membrane separation, and electrochemical extraction methods are being developed as alternatives or complements to traditional solvent extraction. These technologies promise to reduce waste volumes, lower energy consumption, and improve selectivity, potentially making it economically viable to operate separation plants at smaller scales in Western jurisdictions where environmental standards are more stringent. Government research funding through the U.S. Critical Minerals Research Initiative, the EU Horizon Europe program, and Australia's CSIRO is supporting these R&D efforts. The coming decade will be decisive in determining whether technological advances can enable a meaningful build-out of separation capacity outside China, fundamentally reshaping the geography of the rare earth and critical mineral value chain.