The atomic-scale structure of rare earth elements in deep-sea sediments facilitates their extractability
Abstract
Deep-sea rare earth elements (REEs) have attracted global interest as terrestrial resources become less available and demand rises sharply. Seafloor REEs are hosted in authigenic carbonate fluorapatite (a-CFA), formed by the precipitation of calcium and phosphate, and in biogenic carbonate fluorapatite (b-CFA), derived from marine organisms' skeletons. The ease with which REEs can be extracted from pelagic sediments via acid leaching challenges the common view that they are structurally incorporated into CFA, given fluorapatite's low solubility. This apparent paradox was elucidated by investigating the nanostructure of samarium (Sm), used as a chemical REE probe. Using transmission electron microscopy and X-ray absorption spectroscopy, we found that the CFA crystals are nanosized and that Sm is not incorporated into the CFA lattice but instead primarily resides in an amorphous phase surrounding the a-CFA and b-CFA nanocrystals. At the atomic scale, Sm has a disordered apatitic bonding environment, and atomistic modeling suggests it clusters with other REEs. The facile extractability of REEs from pelagic sediments is attributed to the poor crystallinity of the host matrix at the atomic scale. This study demonstrates that understanding the location and atomic structure of critical elements enables quantitative prediction of their macroscopic properties. This knowledge can help improve recovery processes and inform the design of more efficient remediation strategies that protect the environment and public health.
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BibTeX
@article{manceau2026atomicscale,
title = {{The atomic-scale structure of rare earth elements in deep-sea sediments facilitates their extractability}},
author = {Alain Manceau and Andrea Giacomelli and Yan Li and Anne-Claire Gaillot and Jianlin Liao and Lorenzo Spadini and Andrea Koschinsky and Olivier Mathon and Stephan N. Steinmann},
journal = {Communications Earth \& Environment},
year = {2026},
month = jul,
doi = {10.1038/s43247-026-03848-7},
url = {https://hal.science/hal-05762869v2},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - The atomic-scale structure of rare earth elements in deep-sea sediments facilitates their extractability
AU - Alain Manceau
AU - Andrea Giacomelli
AU - Yan Li
AU - Anne-Claire Gaillot
AU - Jianlin Liao
AU - Lorenzo Spadini
AU - Andrea Koschinsky
AU - Olivier Mathon
AU - Stephan N. Steinmann
PY - 2026
DA - 2026/07/28
JO - Communications Earth & Environment
DO - 10.1038/s43247-026-03848-7
UR - https://hal.science/hal-05762869v2
AB - Deep-sea rare earth elements (REEs) have attracted global interest as terrestrial resources become less available and demand rises sharply. Seafloor REEs are hosted in authigenic carbonate fluorapatite (a-CFA), formed by the precipitation of calcium and phosphate, and in biogenic carbonate fluorapatite (b-CFA), derived from marine organisms' skeletons. The ease with which REEs can be extracted from pelagic sediments via acid leaching challenges the common view that they are structurally incorporated into CFA, given fluorapatite's low solubility. This apparent paradox was elucidated by investigating the nanostructure of samarium (Sm), used as a chemical REE probe. Using transmission electron microscopy and X-ray absorption spectroscopy, we found that the CFA crystals are nanosized and that Sm is not incorporated into the CFA lattice but instead primarily resides in an amorphous phase surrounding the a-CFA and b-CFA nanocrystals. At the atomic scale, Sm has a disordered apatitic bonding environment, and atomistic modeling suggests it clusters with other REEs. The facile extractability of REEs from pelagic sediments is attributed to the poor crystallinity of the host matrix at the atomic scale. This study demonstrates that understanding the location and atomic structure of critical elements enables quantitative prediction of their macroscopic properties. This knowledge can help improve recovery processes and inform the design of more efficient remediation strategies that protect the environment and public health.
SN - 2662-4435
ER -