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Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays
The surface mining and heap leaching of China's ion-adsorption rare-earth resources have caused severe environmental damage, there is a need to better understand Rare Earth leaching from Clay ore with the use of agglomerates that improve the permeability of the ore during heap leaching operation. Th...
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| Format: | Thesis |
| Language: | English |
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Department of Chemical Engineering
2024
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| _version_ | 1867613256983511040 |
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| access_status_str | Open Access |
| author | Miiro, Eddy |
| author2 | Petersen, Joachim |
| author_browse | Miiro, Eddy Petersen, Joachim |
| author_facet | Petersen, Joachim Miiro, Eddy |
| author_sort | Miiro, Eddy |
| collection | Thesis |
| description | The surface mining and heap leaching of China's ion-adsorption rare-earth resources have caused severe environmental damage, there is a need to better understand Rare Earth leaching from Clay ore with the use of agglomerates that improve the permeability of the ore during heap leaching operation. The practice of in-situ leaching has also revealed serious environmental problems including underground contamination, mine collapses, and landslides. The performance of lixiviants in extracting Rare Earth has been compared in many studies however this has been carried out in agitated systems and the heap leach scenario is different from agitated systems. This limits the understanding of poor heap permeability and post-closure stability whereas un-agitated leaching of Rare Earth from Clay agglomerates gives a better understanding of diffusion, heap permeability, and material balance to mimic the heap leach scenario. A comprehensive understanding of the leaching mechanism is crucial for achieving high extraction efficiency with low cost and less environmental impact. A series of inorganic salts with different concentrations were employed to leach the Ion-adsorption rare earth agglomerates, and the relationship between the leaching efficiency of rare earth and reagent type was investigated in unagitated systems. This study showed that ammonium sulfate extracts less aluminum content than magnesium chloride. Even when magnesium sulfate (hydrate) extracts less aluminum (impurity in Pregnant Leach Solution) content than the other lixiviants used in the study, magnesium sulfate extracts less Rare Earth Elements (REE) compared to the other lixiviants in the same leaching time, this was an unexpected result when magnesium sulfate hydrate was used instead of anhydrous magnesium sulfate that was much more expensive (per mass) compared to the prices of the other leaching reageants. Therefore the lixiviant of preference in terms of REE extraction from ion adsorption clays in un-agitated systems is in the order (NH4)2SO4 > MgCl2.6H2O > NaCl > MgSO4.7H2O. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/39674 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:15.376Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Department of Chemical Engineering |
| publisherStr | Department of Chemical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/39674 Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays Miiro, Eddy Petersen, Joachim Engineering The surface mining and heap leaching of China's ion-adsorption rare-earth resources have caused severe environmental damage, there is a need to better understand Rare Earth leaching from Clay ore with the use of agglomerates that improve the permeability of the ore during heap leaching operation. The practice of in-situ leaching has also revealed serious environmental problems including underground contamination, mine collapses, and landslides. The performance of lixiviants in extracting Rare Earth has been compared in many studies however this has been carried out in agitated systems and the heap leach scenario is different from agitated systems. This limits the understanding of poor heap permeability and post-closure stability whereas un-agitated leaching of Rare Earth from Clay agglomerates gives a better understanding of diffusion, heap permeability, and material balance to mimic the heap leach scenario. A comprehensive understanding of the leaching mechanism is crucial for achieving high extraction efficiency with low cost and less environmental impact. A series of inorganic salts with different concentrations were employed to leach the Ion-adsorption rare earth agglomerates, and the relationship between the leaching efficiency of rare earth and reagent type was investigated in unagitated systems. This study showed that ammonium sulfate extracts less aluminum content than magnesium chloride. Even when magnesium sulfate (hydrate) extracts less aluminum (impurity in Pregnant Leach Solution) content than the other lixiviants used in the study, magnesium sulfate extracts less Rare Earth Elements (REE) compared to the other lixiviants in the same leaching time, this was an unexpected result when magnesium sulfate hydrate was used instead of anhydrous magnesium sulfate that was much more expensive (per mass) compared to the prices of the other leaching reageants. Therefore the lixiviant of preference in terms of REE extraction from ion adsorption clays in un-agitated systems is in the order (NH4)2SO4 > MgCl2.6H2O > NaCl > MgSO4.7H2O. 2024-05-21T13:03:24Z 2024-05-21T13:03:24Z 2023 2024-05-21T12:23:20Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/39674 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment |
| spellingShingle | Engineering Miiro, Eddy Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| thesis_degree_str | Master's |
| title | Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| title_full | Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| title_fullStr | Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| title_full_unstemmed | Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| title_short | Hydrometallurgical Processing Of Rare Earth Elements From Ion Adsorption Clays |
| title_sort | hydrometallurgical processing of rare earth elements from ion adsorption clays |
| topic | Engineering |
| url | http://hdl.handle.net/11427/39674 |
| work_keys_str_mv | AT miiroeddy hydrometallurgicalprocessingofrareearthelementsfromionadsorptionclays |