Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation
Neodymium-iron-boron (NdFeB) has become the most prominent permanent magnet alloy, with a wide variety of applications and an ever-increasing demand. Their recycling is important for securing the supply of critical raw materials used in their manufacturing. The use of organic acids such as acetic ac...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-10-01
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| Series: | Cleaner Engineering and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666790822001495 |
| _version_ | 1811267019983552512 |
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| author | Joni Niskanen Manu Lahtinen Siiri Perämäki |
| author_facet | Joni Niskanen Manu Lahtinen Siiri Perämäki |
| author_sort | Joni Niskanen |
| collection | DOAJ |
| description | Neodymium-iron-boron (NdFeB) has become the most prominent permanent magnet alloy, with a wide variety of applications and an ever-increasing demand. Their recycling is important for securing the supply of critical raw materials used in their manufacturing. The use of organic acids such as acetic acid has been of recent interest for the recycling of waste NdFeB magnets. Despite achieving good leaching efficiencies, the published literature has not properly investigated the effects of key factors influencing the acetic acid leaching process and their respective interactions, which has led to conflicting findings as to what conditions are optimal. The present work goes to show that no such optimum exists by taking a look at the major factors (concentration, solid-to-liquid ratio, time, and temperature) and their interactions. The results show that leaching efficiencies >95% and even up to 100% can be achieved using a variety of different conditions showing that the leaching reaction is quite flexible, which is helpful for a potential upscaling of the process. The separation of the leached elements presents another problem in NdFeB magnet processing. As a novel application, this work investigated iron separation from the acetic acid leachate by the means of simple and inexpensive aeration. It was found that up to 99% of iron could be precipitated as FeO(OH) (goethite) within 2 h at pH 5 and 80 °C, while only minor neodymium co-precipitation was observed (5%). Separation of iron from the leachate can help obtain purer REE products in further processing. |
| first_indexed | 2024-04-12T20:53:49Z |
| format | Article |
| id | doaj.art-bd24ac87f4f14d548599ca14c6685f3f |
| institution | Directory Open Access Journal |
| issn | 2666-7908 |
| language | English |
| last_indexed | 2024-04-12T20:53:49Z |
| publishDate | 2022-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Cleaner Engineering and Technology |
| spelling | doaj.art-bd24ac87f4f14d548599ca14c6685f3f2022-12-22T03:17:02ZengElsevierCleaner Engineering and Technology2666-79082022-10-0110100544Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitationJoni Niskanen0Manu Lahtinen1Siiri Perämäki2Corresponding author.; Department of Chemistry, University of Jyväskylä, FinlandDepartment of Chemistry, University of Jyväskylä, FinlandDepartment of Chemistry, University of Jyväskylä, FinlandNeodymium-iron-boron (NdFeB) has become the most prominent permanent magnet alloy, with a wide variety of applications and an ever-increasing demand. Their recycling is important for securing the supply of critical raw materials used in their manufacturing. The use of organic acids such as acetic acid has been of recent interest for the recycling of waste NdFeB magnets. Despite achieving good leaching efficiencies, the published literature has not properly investigated the effects of key factors influencing the acetic acid leaching process and their respective interactions, which has led to conflicting findings as to what conditions are optimal. The present work goes to show that no such optimum exists by taking a look at the major factors (concentration, solid-to-liquid ratio, time, and temperature) and their interactions. The results show that leaching efficiencies >95% and even up to 100% can be achieved using a variety of different conditions showing that the leaching reaction is quite flexible, which is helpful for a potential upscaling of the process. The separation of the leached elements presents another problem in NdFeB magnet processing. As a novel application, this work investigated iron separation from the acetic acid leachate by the means of simple and inexpensive aeration. It was found that up to 99% of iron could be precipitated as FeO(OH) (goethite) within 2 h at pH 5 and 80 °C, while only minor neodymium co-precipitation was observed (5%). Separation of iron from the leachate can help obtain purer REE products in further processing.http://www.sciencedirect.com/science/article/pii/S2666790822001495Spent NdFeB magnetRare earth elementREECritical raw materialAcetic acid leachingIron precipitation |
| spellingShingle | Joni Niskanen Manu Lahtinen Siiri Perämäki Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation Cleaner Engineering and Technology Spent NdFeB magnet Rare earth element REE Critical raw material Acetic acid leaching Iron precipitation |
| title | Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| title_full | Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| title_fullStr | Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| title_full_unstemmed | Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| title_short | Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| title_sort | acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation |
| topic | Spent NdFeB magnet Rare earth element REE Critical raw material Acetic acid leaching Iron precipitation |
| url | http://www.sciencedirect.com/science/article/pii/S2666790822001495 |
| work_keys_str_mv | AT joniniskanen aceticacidleachingofneodymiummagnetsandironseparationbysimpleoxidativeprecipitation AT manulahtinen aceticacidleachingofneodymiummagnetsandironseparationbysimpleoxidativeprecipitation AT siiriperamaki aceticacidleachingofneodymiummagnetsandironseparationbysimpleoxidativeprecipitation |