Highlights

• SmCo magnets serve high-temperature aerospace and defense applications where NdFeB fails, but face supply risks from scarce samarium and geopolitically sensitive cobalt.
• Hydrometallurgical recycling delivers >99% samarium and ~90% cobalt recovery with lower energy than smelting, while electrochemical routes offer cleaner, modular alternatives.
• SmCo recycling is advancing from research to viable process options that can extend supply, reduce waste, and strengthen ex-China resilience for critical supply chains.

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A new open-access review (opens in a new tab) in the Journal of Rare Earths online January 2026 delivers a timely message for investors, engineers, and policymakers focused on critical-minerals resilience: samarium–cobalt (SmCo) magnets may be a niche market, but they are strategically important—and increasingly recyclable.

SmCo magnets rarely power mainstream EV motors.

Instead, they serve high-temperature, high-reliability applications—aerospace, defense, and demanding industrial systems—where neodymium-iron-boron (NdFeB) magnets can be performance-limited. SmCo magnets can operate up to ~300 °C, offer strong resistance to corrosion and oxidation, and often reduce the need for protective coatings. That performance comes at a cost: samarium is scarce, cobalt is geopolitically sensitive, and SmCo magnets are brittle—generating substantial scrap during manufacturing and at the end of life.

The review synthesizes more than a decade of research showing that hydrometallurgical recycling is the most widely investigated—and often highest-recovery—route for recovering Sm and Co from SmCo magnet waste, typically with lower energy demand than high-temperature smelting.

How SmCo Recycling Works

The process begins with pretreatment—demagnetization and size reduction—to improve downstream leaching efficiency. From there, acid leaching does the heavy lifting, according to the authors. Conventional inorganic acids (HCl, H₂SO₄, HNO₃) can achieve >99% samarium recovery and up to ~90% cobalt recovery, though sulfuric systems can trigger samarium precipitation, and nitric systems raise downstream wastewater and environmental-handling issues.

Greener alternatives using organic acids (e.g., citric/malic) with H₂O₂ can reduce environmental burden, but often deliver lower recoveries (around ~85%), underscoring the trade-off between performance and sustainability.

Separating the Value

After leaching, selectivity becomes everything. Solvent extraction, ionic liquids, deep eutectic solvents, and ion exchange can separate Sm and Co with high precision; in many flowsheets, stripping and recovery steps can exceed ~97% samarium recovery, depending on reagents and conditions. Ionic liquids and deep eutectic solvents stand out for tunability and low volatility, though cost and long-term stability remain practical hurdles.

The Electrochemical Wildcard

Electrochemical routes are especially intriguing: using intact magnets as anodes in non-aqueous systems can reduce acid consumption and waste, while delivering >85% efficiency in demonstrated setups (and potentially higher in optimized systems). These approaches hint at cleaner, more modular recycling architectures.

The Bottom Line for Supply Chains

This review makes a clear point: SmCo recycling is moving from concept to credible process options. The chemistry works; the challenge is scale-up, economics, and integration into real supply chains.

For defense, aerospace, and high-performance industrial markets seeking Ex-China resilience, SmCo recycling won’t replace mining—but perhaps someday it can extend supply, reduce waste, and harden critical supply chains. In a world where resilience matters as much as volume, that’s a quiet but meaningful breakthrough.

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