Preparation of high-purity SiO2 by S-HGMS coupled with mixed-acid leaching : A case study on hematite tailings from Ansteel, China
Copyright © 2023 Elsevier Ltd. All rights reserved.
| Veröffentlicht in: | Waste management (New York, N.Y.). - 1999. - 174(2024) vom: 15. Feb., Seite 240-250 |
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| Weitere Verfasser: | , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2024
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| Zugriff auf das übergeordnete Werk: | Waste management (New York, N.Y.) |
| Schlagworte: | Journal Article Hematite tailings High-purity SiO(2) Industrial solid waste Mixed-acid leaching S-HGMS Silicon Dioxide 7631-86-9 ferric oxide 1K09F3G675 |
| Zusammenfassung: | Copyright © 2023 Elsevier Ltd. All rights reserved. Hematite tailings (HTs) are rich in silica and are used as replacements for fine aggregates in the preparation of construction materials. However, there is scope for a more effective utilization of the valuable elements present in HTs. In this paper, a process for preparing high-purity SiO2 using HTs procured from Ansteel (China) is proposed. HTs were treated using the superconducting high-gradient magnetic separation (S-HGMS) technology, where the silica as part of the nonmagnetic fraction was obtained in the form of a high-silica concentrate, which was then subjected to mixed-acid leaching to dissolve impurities to achieve refined purification. The optimum process conditions for S-HGMS were determined, and the response surface methodology was applied to optimize the process parameters of the mixed-acid leaching process. The process indicators of the mixed-acid leaching step included the leaching time, leaching temperature, and molar ratio of the mixed acids. The optimum process conditions for S-HGMS were as follows: the magnetic strength-to-velocity ratio in the weak magnetic separation stage was set to 0.034 T·s/m whereas it was maintained at 0.076 T·s/m in the strong magnetic separation stage; the pulp concentration was 40 g/L, the pulp velocity was 500 mL/min, and the dispersant concentration was 1 mg/g. Under these conditions, the high-silica pulp was processed. The corresponding SiO2 grade increased from 71.788 % to 95.260 %, and its recovery and yield reached 56.330 % and 42.450 %, respectively. The SiO2 content in the sample increased from 95.260 % to 99.961 %. Further, the mechanisms of the S-HGMS and mixed-acid leaching were revealed. The proposed process is environmentally friendly and operationally inexpensive. It can reduce the amount of HTs by 42.450 %, and the obtained high-purity silica product has high economic value and good industrialization prospects |
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| Beschreibung: | Date Completed 16.01.2024 Date Revised 16.01.2024 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1879-2456 |
| DOI: | 10.1016/j.wasman.2023.11.026 |