Separation (Advanced Column)

Column-based rare earth separation splits a mixed rare earth solution into individual elements inside columns. Some methods run solvent extraction chemistry in column-based contactors. Others, such as chromatography, pack the column with a solid resin (IEA, May 2026). Developers are pursuing them because conventional solvent extraction needs dozens to hundreds of stages, which the International Energy Agency says makes plants large and complex, with high costs and compliance challenges from extensive solvent use.

How column-based rare earth separation differs from solvent extraction

Conventional rare earth separation runs a dissolved feed through long trains of mixer-settlers, where an organic solvent pulls rare earths out stage by stage. The IEA sorts newer approaches into two groups. One keeps the core solvent extraction framework and improves the equipment. The other seeks to replace the solvent extraction structure altogether (IEA).

Ucore's RapidSX sits in the first group. The IEA describes it as replacing large mixer-settler arrays with column-based contactors to speed up the process. Ucore says RapidSX uses contactor columns and phase separators with the same chemistry, and claims faster separation and a smaller equipment footprint (Ucore).

Ion exchange and chromatography sit in the second group. ReElement Technologies is developing ligand-assisted displacement (LAD) chromatography, which the IEA says uses solid-phase resin columns to separate ions one after another in place of liquid-liquid solvent extraction (IEA).

How ion exchange and chromatography separate rare earths

Ion exchange is the older method. Before industrial-scale solvent extraction, it was the main technique for separating rare earths, and it is still used to make high-purity rare earths on a smaller scale, according to a 2025 peer-reviewed paper by Brecht Dewulf and Koen Binnemans (RSC Advances, June 2025). The most common industrial form is cation exchange with elution by complexing agents such as EDTA. How stably each rare earth binds to that eluting ligand controls its separation.

Purdue University said in February 2021 that LAD chromatography was developed in the lab of chemical engineering professor Linda Wang. It described the method as a way to separate and purify rare earths from coal, coal byproducts, recycled permanent magnets and lithium-ion batteries (Purdue).

Who is developing column separation

• Ucore Rare Metals, Ontario and Louisiana. Ucore says its Kingston facility includes a 52-stage RapidSX commercial demonstration plant and serves as a scale-up and technology transfer platform, and names the Louisiana Strategic Metals Complex as RapidSX's first planned commercial deployment (Ucore). REEx reported in July 2026 that Ucore had announced 99.9% purity dysprosium oxide from Kingston for customer qualification, and called it an early-stage milestone (REEx). REEx reported in August 2026 that Ucore had finalized the equipment configuration for a modular unit designed to process about 600 metric tons a year of total rare earth oxides. Ucore said RapidSX performed at or above conventional solvent extraction under the tested conditions. REEx noted that detailed engineering, factory acceptance testing, construction, commissioning and customer qualification were still ahead (REEx).
• ReElement Technologies, Indiana. REEx reported in August 2026 that ReElement said it had commissioned and operated its first commercial-scale germanium production column at Marion, Indiana. Marion's four initial lines target germanium, gallium, light rare earths and heavy rare earths. REEx cautioned that germanium purification does not establish commercial-scale dysprosium and terbium separation and that key commercial metrics had not been disclosed (REEx).
• Maglut Heavy Industries. Maglut's ARC-1 process adapts chromatography and proprietary resin technology, using engineered ligands so that rare earths exit the column one after another. REEx reported in August 2026 that Maglut says pilot-scale processing produced individual oxides at 99.9%+ purity. It added that recovery rates, throughput and cost per kilogram had not been disclosed (REEx).
• USA Rare Earth, Stillwater, Oklahoma. In May 2026, the U.S. Department of Energy selected USA Rare Earth for award negotiations on a pilot-scale continuous ion exchange plant in Stillwater. DOE says selection is not a commitment to issue an award (DOE, May 2026). The company reported that as of June 30, 2026, it had not received funding or signed a final award agreement (USA Rare Earth 10-Q). DOE's project summary says the aim is to turn the company's bench-scale process into a fully automated, continuously operating pre-commercial unit that demonstrates a process superior to incumbent solvent extraction (DOE). Metal Tech News noted that applying continuous ion exchange to rare earth separation at commercial scale remains a technological challenge.

What independent sources say about readiness

The IEA says high-purity separation for magnets is still primarily done by solvent extraction. It adds that ion exchange may be integrated into separation circuits as a complementary step to reach the purity required for individual oxides (IEA).

Capacity is the limit the peer-reviewed paper names. A resin carries a limited number of functional groups, which restricts ion exchange to dilute feeds in the parts-per-million range, while industrial solvent extraction handles feeds of up to hundreds of grams per liter. The authors conclude that each method has its own uses, depending on feed concentration, target purity, economics and technical factors (Dewulf and Binnemans).

The IEA adds that moving new rare earth technologies from the laboratory to commercial operation remains a major hurdle, and that pilot and demonstration plants are capital-intensive and carry significant technical risk (IEA).

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