Acid transformation of bauxite residue: Conversion of its alkaline characteristics
Kong, X., Li, M., Xue, S., Hartley, W., Chen, C., Wu, C., Li, X. and Li, Y. (2016) Acid transformation of bauxite residue: Conversion of its alkaline characteristics. Journal of Hazardous Materials, 324. pp. 382-390.
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William Hartley Acid transformation of bauxite residue 31 Oct 2016 upload.pdf - Accepted Version Download (2MB) | Preview |
Abstract
Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging.
| Item Type: | Article |
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| Keywords: | Bauxite residue, Alkaline transformation, Organic acid, Gypsum combination, NEXAFS analysis |
| Divisions: | Crop and Environment Sciences (to 31.07.20) |
| Depositing User: | Ms Kath Osborn |
| Date Deposited: | 09 Dec 2016 10:23 |
| Last Modified: | 23 Jan 2018 12:49 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/14547 |
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