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Application of Immobilized Amine Sorbents for Recovery of Rare Earth Elements from Aqueous Systems

National Energy Technology Laboratory

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Technology Marketing Summary

Research is active on the development and application of basic immobilized amine sorbents (BIAS) for use in the recovery of rare earth elements (REEs) from aqueous systems. This invention is available for licensing and/or further collaborative research from the U.S. Department of Energy’s National Energy Technology Laboratory.


REEs are essential to our national security, energy independence, environmental future, and economic growth. These elements are an integral component of many high-technology products such as smart phones, lasers, computer hard drives, and medical devices.

REEs are considered rare because they are found in relatively low concentrations and require further processing, which is technically and economically challenging. Control of the world’s operating REE mines is heavily consolidated, which has resulted market insecurities.

The demand for REEs has grown significantly, stimulating a need for economically feasible approaches for REE recovery from domestic sources. Current methods for the recovery of REEs are flawed—some rely on expensive raw materials and/or equipment, others produce inferior REEs recovered from aqueous streams. There is a need for new methods that can rapidly, accurately, and economically recover REEs from aqueous environments.

This invention describes the synthesis and use of BIAS sorbents containing a polyetheylenimine (PEI) species covalently attached to a silica surface via a reactive chemical linker. The covalent and water stable PEI-Linker-silica species resists degradation and leaching by water in an aqueous system containing REEs, which are captured by PEI’s amine functional groups (-NH2, -NH, -N).

Compared to existing sorbent materials, the new BIAS materials are easily prepared, structurally stable, recyclable over multiple cycles, and capable of capturing a variety of REEs from flowing aqueous streams with low REE concentrations. These low cost, scalable, and robust materials show promise for commercial-scale processes involving REE capture from flowing aqueous streams or stagnant aqueous environments.

· BIAS sorbents are capable of capturing a variety of REEs from low concentration aqueous systems
· Process uses low cost adsorption materials, which are easy and quick to prepare
· Sorbents are structurally stable and recyclable over multiple cycles
· Sorbents display an absence of affinity for sodium, potassium, calcium, and magnesium, allowing REE capture from water sources without interference from unwanted ions
· Inexpensive, scalable process applicable to commercial scale recovery of REEs
Applications and Industries

· Recovery of REEs from flowing or stagnant aqueous system including, flowback water from oil and natural gas wells, industrial waste streams, and acid leach liquid from dissolving REE from solid earth materials like coal, fly ash, and clays

· Recovery of potentially toxic heavy metals, such as lead, copper, and zinc from aqueous sources including acid mine drainage and drinking water

More Information

U.S. Non-provisional Patent Application No. 15/782, filed October 12, 2017, titled “Stable Immobilized Amine Sorbents for REE and Heavy Metals Recovery from Liquid Sources.”

Inventors: McMahan L. Gray, Brian W. Kail, Walter C. Wilfong, and Qiuming Wang

PCT Application No. PCT/US17/56421, filed October 12, 2017, titled "Stable Immobilized Amine Sorbents for REE and Heavy Metals Recovery from Liquid Sources." 

Inventors: McMahan L. Gray, Brian W. Kail, Walter C. Wilfong, and Qiuming Wang

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Application 20180100065
Materials, methods of making, and methods of using a stable and regenerable immobilized amine sorbents for rare earth element and heavy metal recovery from liquid sources. Embodiments of the invention relate to the novel combination of different polyamines, primarily polyethylenimine Mw=800 (PEI.sub.800), and an epoxysilane, namely 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS), covalently immobilizing the REE and heavy metal-adsorbing amine sites within low cost, porous silica particles.
Technology Status
Development StageAvailabilityPublishedLast Updated

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