TY - JOUR
T1 - The potential of REEs in the Eppawala Phosphate Deposit, Sri Lanka
T2 - REE enrichment, mineralization, and economic significance
AU - Batapola, Nadeera
AU - Ratnayake, Nalin
AU - Abeysinghe, Bandara
AU - Premasiri, Ranjith
AU - Dushyantha, Nimila
AU - Ilankoon, I. M.Saman K.
AU - Chandrajith, Rohana
AU - Rohitha, Sudath
AU - Dissanayake, Kithsiri
AU - Dharmaratne, Pannipitiye
AU - Ratnayake, Amila Sandaruwan
AU - Dilshara, Pubudi
N1 - Funding Information:
This work was supported by the Accelerating Higher Education and Development (AHEAD) Operation of the Ministry of Higher Education of Sri Lanka funded by the World Bank (Grant number: AHEAD/DOR/6026-LK/8743-LK).
Funding Information:
The authors wish to acknowledge the financial support provided by the Accelerating Higher Education and Development (AHEAD) Operation of the Ministry of Higher Education of Sri Lanka funded by the World Bank (AHEAD/DOR/6026-LK/8743-LK). Moreover, the authors acknowledge PXRD, SEM, and XRD analysis facilities provided by the Department of Applied Earth Sciences, Faculty of Applied Sciences, Uva Wellassa University, Badulla, Sri Lanka; the Department of Materials Science and Engineering, Faculty of Engineering, University of Moratuwa, Moratuwa, Sri Lanka; and the Geological Survey and Mines Bureau, Pitakotte, Sri Lanka, respectively.
Funding Information:
The authors wish to acknowledge the financial support provided by the Accelerating Higher Education and Development (AHEAD) Operation of the Ministry of Higher Education of Sri Lanka funded by the World Bank (AHEAD/DOR/6026-LK/8743-LK). Moreover, the authors acknowledge PXRD, SEM, and XRD analysis facilities provided by the Department of Applied Earth Sciences, Faculty of Applied Sciences, Uva Wellassa University, Badulla, Sri Lanka; the Department of Materials Science and Engineering, Faculty of Engineering, University of Moratuwa, Moratuwa, Sri Lanka; and the Geological Survey and Mines Bureau, Pitakotte, Sri Lanka, respectively.
Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2023/9/7
Y1 - 2023/9/7
N2 - The significant role in high-tech and green technologies, recent outstripping demand, and constrained global supply of rare earth elements (REEs) have led to the exploration of phosphate deposits worldwide as a sustainable source for the recovery of REEs as by-products. In this context, the Eppawala Phosphate Deposit (EPD) in Sri Lanka can be considered a potential source for recovering REEs as a by-product. The REE geochemistry and mineralogy of sixty representative samples from the weathered regolith (primary apatite crystals and secondary phosphate matrix) and the carbonatite source rock at the EPD were analyzed. The average total REE content (∑REE) in the weathered regolith ranged from 2500 to 6092 ppm, with higher enrichment of light REEs than heavy REEs. The weathered regolith was highly enriched in REEs compared to the parent carbonatite due to residual enrichment of apatite with calcite and dolomite dissolution. Furthermore, REE immobilization during matrix formation results from the retention of REEs in fluorapatite and hydroxylapatite. Mineralogical analyses revealed that the major REE ore minerals in the EPD are apatite group minerals. Despite the relatively low REE grade (~ 0.48% total rare earth oxide) compared to the other phosphate deposits in the world, this deposit is significantly enriched in critical and highly demanded REEs, such as Nd (54,468 tonnes), Pr (17,994 tonnes), and Tb (2,897 tonnes). Therefore, with upgraded extraction techniques, the EPD could become a potential source of REEs that could contribute to maintaining a sustainable REE supply chain in the future.
AB - The significant role in high-tech and green technologies, recent outstripping demand, and constrained global supply of rare earth elements (REEs) have led to the exploration of phosphate deposits worldwide as a sustainable source for the recovery of REEs as by-products. In this context, the Eppawala Phosphate Deposit (EPD) in Sri Lanka can be considered a potential source for recovering REEs as a by-product. The REE geochemistry and mineralogy of sixty representative samples from the weathered regolith (primary apatite crystals and secondary phosphate matrix) and the carbonatite source rock at the EPD were analyzed. The average total REE content (∑REE) in the weathered regolith ranged from 2500 to 6092 ppm, with higher enrichment of light REEs than heavy REEs. The weathered regolith was highly enriched in REEs compared to the parent carbonatite due to residual enrichment of apatite with calcite and dolomite dissolution. Furthermore, REE immobilization during matrix formation results from the retention of REEs in fluorapatite and hydroxylapatite. Mineralogical analyses revealed that the major REE ore minerals in the EPD are apatite group minerals. Despite the relatively low REE grade (~ 0.48% total rare earth oxide) compared to the other phosphate deposits in the world, this deposit is significantly enriched in critical and highly demanded REEs, such as Nd (54,468 tonnes), Pr (17,994 tonnes), and Tb (2,897 tonnes). Therefore, with upgraded extraction techniques, the EPD could become a potential source of REEs that could contribute to maintaining a sustainable REE supply chain in the future.
KW - Apatite
KW - Phosphate rock
KW - Rare earth elements
KW - Sustainability
KW - Weathering
UR - http://www.scopus.com/inward/record.url?scp=85170355218&partnerID=8YFLogxK
U2 - 10.1007/s12665-023-11135-3
DO - 10.1007/s12665-023-11135-3
M3 - Article
AN - SCOPUS:85170355218
SN - 1866-6280
VL - 82
JO - Environmental Earth Sciences
JF - Environmental Earth Sciences
IS - 19
M1 - 446
ER -