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Efficiency of Sulfuric Acid on Selective Scandium Leachability from Bauxite Residue †

School of Chemical Engineering (Chem. Eng.), National Technical University of Athens (NTUA), 9 Iroon Polytechniou St., 15780 Athens, Greece
Authors to whom correspondence should be addressed.
This paper is part of the oral presentation entitled “Mineral Acid Leaching of Scandium from Bauxite Residue”, presented by Ochsenkuehn-Petropoulou, M. Proceedings of the International Bauxite Residue Valorization and Best Practices Conference-BR2018, Athens, Greece, 7–10 May 2018. Available online: (accessed on 20 September 2018). The whole proceedings are not available online and only a hard copy of them exists.
Metals 2018, 8(11), 915;
Received: 3 October 2018 / Revised: 26 October 2018 / Accepted: 5 November 2018 / Published: 7 November 2018
Bauxite residue (BR) is a well promising resource for critical metals, especially scandium (Sc), a rare and expensive metal with increasing applications in advanced technology. Greek BR seems to significantly favor a commercially viable recovery of Sc combining optimized leaching and advanced separation techniques. Leaching with mineral acids emerges as the dominant selection compared to other techniques. This study investigates an optimized leaching condition set for Sc recovery, using the most advantageous option of sulfuric acid. The main target is to develop a leaching scale-up process to be established in the premises of Mytilineos S.A. (formerly Aluminium of Greece, the largest Greek alumina and aluminum producer), taking into account the feed requirements of a subsequent advanced ion exchanged procedure. Several parameters were studied individually or combined in order to achieve high Sc concentration in the leachate and to ensure selectivity, especially concerning iron. The most significant parameters prove to be the solid-to-liquid ratio (S/L), the final pH value, and the leachate’s recycling. The proposed process, with low molarities of sulfuric acid and ambient conditions, integrates rapidly, leading to high and selective Sc recovery. Finally, a leaching process flow diagram under continuous operation on an industrial scale is developed. View Full-Text
Keywords: bauxite residue; scandium; leaching; sulfuric acid bauxite residue; scandium; leaching; sulfuric acid
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MDPI and ACS Style

Ochsenkuehn-Petropoulou, M.; Tsakanika, L.-A.; Lymperopoulou, T.; Ochsenkuehn, K.-M.; Hatzilyberis, K.; Georgiou, P.; Stergiopoulos, C.; Serifi, O.; Tsopelas, F. Efficiency of Sulfuric Acid on Selective Scandium Leachability from Bauxite Residue. Metals 2018, 8, 915.

AMA Style

Ochsenkuehn-Petropoulou M, Tsakanika L-A, Lymperopoulou T, Ochsenkuehn K-M, Hatzilyberis K, Georgiou P, Stergiopoulos C, Serifi O, Tsopelas F. Efficiency of Sulfuric Acid on Selective Scandium Leachability from Bauxite Residue. Metals. 2018; 8(11):915.

Chicago/Turabian Style

Ochsenkuehn-Petropoulou, Maria, Lamprini-Areti Tsakanika, Theopisti Lymperopoulou, Klaus-Michael Ochsenkuehn, Konstantinos Hatzilyberis, Paraskevas Georgiou, Chrysanthos Stergiopoulos, Olga Serifi, and Fotis Tsopelas. 2018. "Efficiency of Sulfuric Acid on Selective Scandium Leachability from Bauxite Residue" Metals 8, no. 11: 915.

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