The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

Platon N. Gamaletsos; Athanasios Godelitsas; Takeshi Kasama; Alexei Kuzmin; Markus Lagos; Theo J. Mertzimekis; Jörg Göttlicher; Ralph Steininger; Stelios Xanthos; Yiannis Pontikes; George N. Angelopoulos; Charalampos Zarkadas; Aleksandr Komelkov; Evangelos Tzamos; Anestis Filippidis

doi:10.1038/srep21737

The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

Platon N. Gamaletsos^*
, Athanasios Godelitsas
, Takeshi Kasama
, Alexei Kuzmin
, Markus Lagos
, Theo J. Mertzimekis
, Jörg Göttlicher
, Ralph Steininger
, Stelios Xanthos
, Yiannis Pontikes
, George N. Angelopoulos
, Charalampos Zarkadas
, Aleksandr Komelkov
, Evangelos Tzamos
, Anestis Filippidis

^*Corresponding author for this work

EXAFS Spectroscopy Laboratory, Institute of Solid State Physics

Technical University of Denmark
National and Kapodistrian University of Athens
Karlsruhe Institute of Technology
Aristotle University of Thessaloniki
Alexander Technological Educational Institute of Thessaloniki
KU Leuven
University of Patras
Spectris plc

Research output: Contribution to journal › Article › peer-review

28 Citations (Scopus)

Abstract

We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant "Al-Fe-Ca-Ti-Si-Na-Cr matrix", appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g^-1), along with minor U (15 μg g^-1), which are responsible for radioactivity (355 and 133 Bq kg^-1 for ²³²Th and ²³⁸U, respectively) with a total dose rate of 295 nGy h^-1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th⁴⁺ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca_0.8Na_0.2TiO₃ and crystallites observed in nanoscale. The Th L_III-edge EXAFS spectra demonstrated that Th⁴⁺ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca²⁺ sites, rather than Ti⁴⁺ sites. That is most likely the reason of no Th release in Mediterranean seawater.

Original language	English
Article number	21737
Journal	Scientific Reports
Volume	6
DOIs	https://doi.org/10.1038/srep21737
Publication status	Published - 22 Feb 2016

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Gamaletsos, P. N., Godelitsas, A., Kasama, T., Kuzmin, A., Lagos, M., Mertzimekis, T. J., Göttlicher, J., Steininger, R., Xanthos, S., Pontikes, Y., Angelopoulos, G. N., Zarkadas, C., Komelkov, A., Tzamos, E., & Filippidis, A. (2016). The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud). Scientific Reports, 6, Article 21737. https://doi.org/10.1038/srep21737

@article{9c92d2fd25ff464080b98bd4d644b5fd,

title = "The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)",

abstract = "We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant {"}Al-Fe-Ca-Ti-Si-Na-Cr matrix{"}, appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g-1), along with minor U (15 μg g-1), which are responsible for radioactivity (355 and 133 Bq kg-1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h-1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS \& HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater.",

author = "Gamaletsos, \{Platon N.\} and Athanasios Godelitsas and Takeshi Kasama and Alexei Kuzmin and Markus Lagos and Mertzimekis, \{Theo J.\} and J{\"o}rg G{\"o}ttlicher and Ralph Steininger and Stelios Xanthos and Yiannis Pontikes and Angelopoulos, \{George N.\} and Charalampos Zarkadas and Aleksandr Komelkov and Evangelos Tzamos and Anestis Filippidis",

year = "2016",

month = feb,

day = "22",

doi = "10.1038/srep21737",

language = "English",

volume = "6",

journal = "Scientific Reports",

issn = "2045-2322",

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Gamaletsos, PN, Godelitsas, A, Kasama, T, Kuzmin, A, Lagos, M, Mertzimekis, TJ, Göttlicher, J, Steininger, R, Xanthos, S, Pontikes, Y, Angelopoulos, GN, Zarkadas, C, Komelkov, A, Tzamos, E & Filippidis, A 2016, 'The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)', Scientific Reports, vol. 6, 21737. https://doi.org/10.1038/srep21737

TY - JOUR

T1 - The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

AU - Gamaletsos, Platon N.

AU - Godelitsas, Athanasios

AU - Kasama, Takeshi

AU - Kuzmin, Alexei

AU - Lagos, Markus

AU - Mertzimekis, Theo J.

AU - Göttlicher, Jörg

AU - Steininger, Ralph

AU - Xanthos, Stelios

AU - Pontikes, Yiannis

AU - Angelopoulos, George N.

AU - Zarkadas, Charalampos

AU - Komelkov, Aleksandr

AU - Tzamos, Evangelos

AU - Filippidis, Anestis

PY - 2016/2/22

Y1 - 2016/2/22

N2 - We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant "Al-Fe-Ca-Ti-Si-Na-Cr matrix", appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g-1), along with minor U (15 μg g-1), which are responsible for radioactivity (355 and 133 Bq kg-1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h-1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater.

AB - We present new data about the chemical and structural characteristics of bauxite residue (BR) from Greek Al industry, using a combination of microscopic, analytical, and spectroscopic techniques. SEM-EDS indicated a homogeneous dominant "Al-Fe-Ca-Ti-Si-Na-Cr matrix", appearing at the microscale. The bulk chemical analyses showed considerable levels of Th (111 μg g-1), along with minor U (15 μg g-1), which are responsible for radioactivity (355 and 133 Bq kg-1 for 232Th and 238U, respectively) with a total dose rate of 295 nGy h-1. Leaching experiments, in conjunction with SF-ICP-MS, using Mediterranean seawater from Greece, indicated significant release of V, depending on S/L ratio, and negligible release of Th at least after 12 months leaching. STEM-EDS/EELS & HR-STEM-HAADF study of the leached BR at the nanoscale revealed that the significant immobility of Th4+ is due to its incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th LIII-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely the reason of no Th release in Mediterranean seawater.

UR - https://www.scopus.com/pages/publications/84959141015

U2 - 10.1038/srep21737

DO - 10.1038/srep21737

M3 - Article

AN - SCOPUS:84959141015

SN - 2045-2322

VL - 6

JO - Scientific Reports

JF - Scientific Reports

M1 - 21737

ER -

The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

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