Assessment of bottom ash landfilled at Ceplea Valley (Romania) as a source of rare earth elements

• Type: Article in International Scientific Journal
• Date: 2019

Authors

B. Valentim (Author) FCUP; Abagiu, AT (Author) Other; Anghelescu, L (Author) Other; Flores, D (Author) FCUP; French, D (Author) Other; Paula Alexandra Goncalves (Author) FCUP; Guedes, A (Author) FCUP; Popescu, LG (Author) Other; Predeanu, G (Author) Other; Ribeiro, J (Author) FCUP; Santos, AC (Author) Other; Slavescu, V (Author) Other; Ward, CR (Author) Other

Journal

Title: International Journal of Coal Geology

Vol. 201

Pages: 109-126

ISSN: 0166-5162

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 24 Citations

Scopus - 24 Citations

Other information

Authenticus ID: P-00Q-4DH

DOI: 10.1016/j.coal.2018.11.019

Abstract (EN): This study aims to demonstrate, by a detailed fundamental analysis, an alternative for the production of rare earth elements, including yttrium and scandium (REY + Sc), from the historic bottom ash deposit at Ceplea Valley (Romania). Twenty-five samples representing 20% of this deposit were studied using a combination of chemical (proximate and elemental analysis), mineralogical and petrographic techniques. This analysis also included, for the first time, a scanning electron microscopy with X-ray microanalysis SEM/EDS point-count method for tracking REE-bearing minerals. The results showed that the bulk REY + Sc concentration is consistent throughout the landfill, and a bottom ash composite sample was made to assess the chemical composition of several size fractions. Based on Seredin-Dai's criteria (Seredin and Dai, 2012), the plot of the outlook coefficient of REY ores (C-outl) versus the percentage of critical REY of the deposit samples (278 ppm in average) and of the composite sample size fractions shows that this ash is a potentially promising source of REY. However, Gd seems to be the most promising element, especially in the 0.090-0.125 mm and < 0.063 mm size fractions. Finally, the SEM/EDS results show that the only REE-bearing minerals (except one case with Y, Gd, Er, Dy) are micrometre-sized phosphate grains with Ce, La and Nd, with an average diameter of 4.85 mu m, which do not entirely account for the total REE determined by ICP-MS and indicates that a fraction of these elements must be dispersed in the glassy aluminosilicate matrix.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 18