Enhanced alumina extraction from kaolin by thermochemical activation using charcoal
| Autor: | Amr B. ElDeeb, Vyacheslav N. Brichkin, Martin Bertau, Mahmoud E. Awad, Yulia A. Savinova |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Clay Minerals. 56:269-283 |
| ISSN: | 1471-8030 0009-8558 |
| DOI: | 10.1180/clm.2022.7 |
| Popis: | The present work aims to increase the alumina percentage recovery (APR) extracted from kaolinviathe addition of 0.5–4.0 wt.% charcoal as a thermochemical fluxing agent in the lime-sintering process at 1260–1360°C. The transformation, microstructural and microtextural changes and self-disintegration performance were characterized using thermogravimetric analysis and differential scanning calorimetry, X-ray diffraction/X-ray fluorescence, scanning electron microscopy coupled with energy-dispersive spectroscopy and laser diffraction particle-size distribution analysis. The optimum enhancement of APR, from 77.7% to 87.40%, was obtained by sintering at 1360°C with the addition of 1.5% charcoal. With further increase of the charcoal content to 4%, the APR reduced to 75.6%. Combustion of ≤1.5% charcoal provided additional heat that amorphized the crystalline calcium aluminate into highly leachable amorphous phases with improved self-disintegration efficiency. Sintering at temperatures of >1360°C or with charcoal contents >4% led to mullite crystallization and decreased alumina leachability, thereby reducing the APR. Charcoal is a cost-effective and energy-efficient activator to increase the APR extracted from kaolin. |
| Databáze: | OpenAIRE |
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