| Title: |
The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud) |
| Authors: |
Gkamaletsos, Platon; Godelitsas, Athanasios; Kasama, Takeshi; Kuzmin, Alexei; Lagos, Markus; Mertzimekis, Theo J.; Göttlicher, Jörg; Steininger, Ralph; Xanthos, Stelios; Pontikes, Yiannis; Angelopoulos, George N.; Zarkadas, Charalampos; Komelkov, Aleksandr; Tzamos, Evangelos; Filippidis, Anestis |
| Source: |
Gkamaletsos , P , 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 , vol. 6 , 21737 . https://doi.org/10.1038/srep21737 |
| Publication Year: |
2016 |
| Collection: |
Technical University of Denmark: DTU Orbit / Danmarks Tekniske Universitet |
| Description: |
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 mu g g(-1)), along with minor U (15 mu g g(-1)), which are responsible for radioactivity (355 and 133 Bq kg(-1) for Th-232 and U-238, 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 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. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| DOI: |
10.1038/srep21737 |
| Availability: |
https://orbit.dtu.dk/en/publications/3fb71b5f-3f27-41e1-ace2-79a2418ac911; https://doi.org/10.1038/srep21737; https://backend.orbit.dtu.dk/ws/files/123621607/The_role_of_nano_perovskite.pdf |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.F1D2027F |
| Database: |
BASE |