Rare Earth Element Extraction from Coal Fly Ash
- Skyhaven Systems, LLC, Westford, MA (United States)
Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. Currently, China produces about 85% of the world supply of rare earth metals and oxides. Approaches for recovering rare-earth species from natural and waste sources is increasingly important to reduce our dependence on foreign entities. REEs can be recovered from several waste sources including coal fly ash. Coal and coal fly ash are potentially economical sources of REE. New separation and recovery technologies are sought to enable more rapid, flexible, efficient, environmentally-friendly extraction and separations of individual lanthanides from mixtures with the goal of increasing the domestic supply of rare earth elements and decreasing the costs of processing high purity metals. In this Phase I program, Skyhaven Systems, LLC, developed a unique process to recover rare earth elements from fly ash. We successfully demonstrated recovery of rare earth metals from conventional ionic liquids, and less-expensive deep eutectic solvent (DESs) solutions containing rare earth oxides and phosphates. A selective potential technique was used to enrich deposits in single rare earths from binary systems, demonstrating a pathway to separation. Complexing agents were investigated to shift reduction potentials in mixtures of rare earths with the goal of enabling greater separation In the Phase I program we also investigated the competing electrochemistry of non-rare earth fly ash components. As expected, these species complicate the extraction of rare earths from fly ash. We explored and demonstrated pre-treatment options to remove iron and aluminum, as well as demonstrate a two-step process to selectively extract rare earths into an ionic liquid and then recover using our electrochemical extraction technology. Our approach has an economic advantage over conventional technologies based on acid leaching where 87% of the operating cost is in consumables. In our approach, the ionic liquids are re-used, resulting in an economically viable approach to the recovery of rare earths from coal fly ash.
- Research Organization:
- Skyhaven Systems, LLC, Westford, MA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- SC0018528
- OSTI ID:
- 1491487
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- DOE-Skyhavensystems-18528
- Country of Publication:
- United States
- Language:
- English
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