Abstract
Rare earth elements or REEs are a vital and irreplaceable part of our modern technological and digital industries. Among the REEs that are the most critical to be recovered are Ce, La, and particularly, Nd, and Y, due to high demand and at a potential future supply risk. Innovative techniques must be considered to recover REEs from secondary resources. In this study, REEs are extracted from iron mining sludge from Central Anatolia in Turkey. Two different acid solutions were compared, one with a higher acid content (120 ml HCl and 80 ml HNO3 per liter) and one with lower acid content (20 ml HNO3 per liter). Nanofiltration, as a process to concentrate the acidic leachate and increase the REE concentration, was carried out at pH levels of 1.5, 2.5, and 3.5 and under 12, 18, and 24 bar operating pressures. SLM studies had been carried out using a PVDF membrane with a pore diameter of 0.45 μm, with three different carriers to separate the REEs from other major elements in the concentrated leachate. Through this analysis, the optimum operating conditions for nanofiltration are at pH 3.5 at 12 bar, using the leach with low acidity, achieving about 90% recovery efficiency of the REEs. SLM studies using 0.3M D2EHPA, with a 3-h reaction time, showed the highest mass flux values for the REEs. Nanofiltration and SLM represent novel methods of REE concentration and extraction from iron mining sludge.
Original language | English |
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Pages (from-to) | 61137-61150 |
Number of pages | 14 |
Journal | Environmental Science and Pollution Research |
Volume | 28 |
Issue number | 43 |
DOIs | |
Publication status | Published - Nov 2021 |
Bibliographical note
Publisher Copyright:© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Funding
AFS and BKM were responsible for the writing and editing of the proposed article. Research work, collection, analysis, and interpretation of data were conducted by AFS, AY, and GT. Conceptualization and study design were determined by IK, MW, BKM, and AY. IK was also responsible for funding acquisition and supervision.
Funders | Funder number |
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TUBITAK | 117Y357 |
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu |
Keywords
- Nanofiltration
- Rare earth elements
- Recovery
- Red mud
- Supported liquid membranes