Rare earth elements (REE) are critical materials in advanced communications, defense and clean energy technologies. Extraction of REE from coal byproducts represents a potential new supply of REE and a secondary usage for coal resources. The objective of this study was to find a sensitive method for rapid detection of REE derived from coal fly ash. In the present work, we report an approach based on the strong luminescence of REE in fluoride mineral hosts. REE can be precipitated by addition of ammonium fluoride to hydrochloric acid leachates of coal fly ash. Eu, Tb, Er, Pr, Nd, Ho, and Tm were detected in precipitates generated from the leachates at ppm levels based on their characteristic excitation and emission wavelengths. Mixed Solvent Electrolyte (MSE model) thermodynamic simulations and x-ray diffraction (XRD) and inductively coupled plasma optical emission spectroscopy (ICP-OES) measurements have been performed to study the leaching and precipitation behaviors. While characterization of the precipitates as well as thermodynamic simulations indicate the formation of complex mineral assemblages, we can spectrally discriminate between the different lanthanide elements in the fly ash. Our results are promising for the development of a novel method for sensitive REE detection in complex environmental samples, with potential applications in REE prospecting as well as in monitoring of REE refinement processes.

Sensing rare earth elements by luminescence properties in coal fly ash

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.