Selective Recovery of Rare Earth Elements using Green Foam Flotation
| dc.contributor.advisor | Ponnurangam, Sathish | |
| dc.contributor.author | Shetty, Sharath Ananda | |
| dc.contributor.committeemember | Achari, Gopal | |
| dc.contributor.committeemember | Mahinpey, Nader | |
| dc.date | 2021-06 | |
| dc.date.accessioned | 2021-05-07T15:49:00Z | |
| dc.date.available | 2021-05-07T15:49:00Z | |
| dc.date.issued | 2021-04-30 | |
| dc.description.abstract | The extraction of REE from the primary ores is a complex process and causes damages to the environment. Hence, recent research efforts in this field have focused on finding alternative separation methods to reduce the costs and environmental impacts of the process. One such alternative approach that is explored in this work is based on the foam flotation method. However, there are not many reports that have explored the efficacy of foam flotation for REE separation under practical conditions. In this work, ion and precipitate types of foam flotation of REE were carried out using a conventional surfactant (sodium dodecyl sulfate, SDS) and a green surfactant (mono-rhamnolipid) to understand the effectiveness of this method. The results for separation and recovery of La3+, Ce3+, Gd3+, and Yb3+ were reported as a single ion flotation (also called individual flotation), group flotation of REE, and REE flotation with gangue ions (Al3+, Zn2+, Ca2+, and Mg2+). Foam flotation with SDS can be controlled by both solution composition and kinetics, to selectively separate desired REE. The monorhamnolipid outperformed SDS in REE recovery from the gangue except for Al3+ and Zn2+. The nature of REE aquo-complexes and their interaction with SDS was explored using La3+ and SDS surfactant. In particular, acid-base titration and NMR experiments were performed and interpreted using quantum chemical simulations (Density Functional Theory, DFT) to understand the pH effects on the coordination number of La3+ and stable hydroxylation states. The DFT optimized La3+ geometries showed that the most stable coordination number is 9 water molecules, followed by 8 and 7. The DFT and experimental NMR revealed La(H2O)6(OH)2 to be the stable structure in the water solution at ~ pH 8. It was found that at high pH using SDS, the La3+ is floated out as La(OH)2SDS through the precipitate flotation pathway, whereas, at low pH, La3+ was floated as La(OH)x(SDS)y complex through ion flotation pathway. It was also found that precipitate flotation can be enabled even at low pH through an increase in the concentration of La3+or SDS by olation. The results showed foam flotations as an effective extraction process of REE by green surfactant for the conditions studied above. Foam flotation can reduce both cost and environmental concerns caused by the conventional extraction process. The mechanistic study showed that the binding of La3+ with anions (hydroxyls or surfactants) depends on the aqueous condition around the La3+ ion. Hence, our results point to great potential for using foam flotation for REE extraction as an alternative to the industrially standard solvent extraction method. | en_US |
| dc.identifier.citation | Shetty, S. A. (2021). Selective Recovery of Rare Earth Elements using Green Foam Flotation (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. | en_US |
| dc.identifier.doi | http://dx.doi.org/10.11575/PRISM/38832 | |
| dc.identifier.uri | http://hdl.handle.net/1880/113372 | |
| dc.language.iso | eng | en_US |
| dc.publisher.faculty | Schulich School of Engineering | en_US |
| dc.publisher.institution | University of Calgary | en |
| dc.rights | University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. | en_US |
| dc.subject | lanthanides; ion flotation; precipitate flotation; green chemistry; lanthanum; cerium; gadolinium; ytterbium; mineral processing; mineral separation; hydrometallurgy | en_US |
| dc.subject.classification | Mineralogy | en_US |
| dc.subject.classification | Engineering--Chemical | en_US |
| dc.title | Selective Recovery of Rare Earth Elements using Green Foam Flotation | en_US |
| dc.type | master thesis | en_US |
| thesis.degree.discipline | Engineering – Chemical & Petroleum | en_US |
| thesis.degree.grantor | University of Calgary | en_US |
| thesis.degree.name | Master of Science (MSc) | en_US |
| ucalgary.item.requestcopy | true | en_US |