Industrial-scale extraction of high value-added kaolin from excavation waste : Demonstration from Xiamen, China
Copyright © 2023 Elsevier Ltd. All rights reserved.
| Publié dans: | Waste management (New York, N.Y.). - 1999. - 163(2023) vom: 15. Mai, Seite 144-153 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2023
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| Accès à la collection: | Waste management (New York, N.Y.) |
| Sujets: | Journal Article Excavation waste Granite weathering Industrialization Iron removal Kaolin extraction Valorization Kaolin 24H4NWX5CO Sand plus... |
| Résumé: | Copyright © 2023 Elsevier Ltd. All rights reserved. Excavation waste from the construction of subways and other underground infrastructures is mainly composed of gravel, sand and clay of minimal economic value, which commonly ends up in landfills. Although the coarse sand and gravel of the excavation waste are typically recycled on site, a large amount of the fine-grained residue must be disposed of due to the prohibition of marine land reclamation in Xiamen, China, leading to an increasingly severe shortage of landfills. In this contribution, a new strategy was successfully developed for industrial-scale extraction of high value-added kaolin from the excavation waste of Xiamen. This strategy can overcome the challenges of complex and variable chemical compositions, high iron contents, low industrial grade, and organic contaminants in the raw materials. Characterization using chemical analysis, powder X-ray diffraction, scanning electron microscopy, and infrared spectroscopy showed that the Xiamen excavation waste originated from granite weathering is mainly composed of kaolinite and quartz, along with high Fe contents and other impurities. The excavation waste was subjected to an intensive process of blunging, grinding, sieving, and classifying, as well as successive iron removal by magnetic separation. Subsequently, the extracted products meet commercial requirements, including those for high-quality kaolin with whiteness and plasticity larger than 90° and 17%, respectively. Moreover, an industrial-scale green production line with an annual treatment capacity of one million tonnes of excavation waste at the utilization rate of 100% was implemented. Hence, this work presents an effective approach for exploiting similar excavation waste around the world to promote sustainable development |
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| Description: | Date Completed 18.04.2023 Date Revised 18.04.2023 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1879-2456 |
| DOI: | 10.1016/j.wasman.2023.03.028 |