Enhanced Precipitation of Gibbsite from Sodium Aluminate Solution by Adding Agglomerated Active Al(OH)<sub>3</sub> Seed
The addition of active seed for increasing the precipitation rate leads to the formation of fine Al(OH)<sub>3</sub> particles that complicates separation of solid from the mother liquor. In this study, the enhanced precipitation of coarse Al(OH)<sub>3</sub> from sodium alumin...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-01-01
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| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/13/2/193 |
| Summary: | The addition of active seed for increasing the precipitation rate leads to the formation of fine Al(OH)<sub>3</sub> particles that complicates separation of solid from the mother liquor. In this study, the enhanced precipitation of coarse Al(OH)<sub>3</sub> from sodium aluminate solution using active agglomerated seed was investigated. Aluminum salt (Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>) were used for active agglomerated seed precipitation at the initial of the process. About 50% of precipitation rate was obtained when these agglomerates were used as a seed in the amount of 20 g L<sup>−1</sup> at 25 °C within 10 h. The agglomerated active seed and precipitate samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). SEM images showed that agglomerates consist of flake-like particles that can be stick together by bayerite (β-Al(OH)<sub>3</sub>) acting as a binder. The precipitation temperature above 35 °C and the high concentration of free alkali (α<sub>k</sub> = 1.645Na<sub>2</sub>O<sub>k</sub>/Al<sub>2</sub>O<sub>3</sub> > 3) lead to the agglomerates refinement that can be associated with the bayerite dissolution. |
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| ISSN: | 2075-4701 |