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Evaluation of aggregate microstructures following natural regeneration in bauxite residue as characterized by synchrotron-based X-ray micro-computed tomography

Zhu, F., Liao, J., Xue, S., Hartley, W., Zou, Q. and Wu, H. (2016) Evaluation of aggregate microstructures following natural regeneration in bauxite residue as characterized by synchrotron-based X-ray micro-computed tomography. Science of The Total Environment, 573. pp. 155-163.

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William Hartley Evaluation of aggregate residue 31 Oct 2016 upload.pdf - Accepted Version
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Official URL: http://doi.org/10.1016/j.scitotenv.2016.08.108

Abstract

Bauxite residue often has poor physical conditions which impede plant growth. Native plant encroachment on a bauxite residue disposal area in Central China reveals that natural regeneration may improve its physicochemical properties. Residue samples collected from three different disposal ages were assessed to evaluate residue micromorphology and three-dimensional (3D) aggregate microstructure under natural regeneration. The residue aggregates in different disposal ages were divided in two sections: macro-aggregate (2–1 mm) and micro-aggregate (0.25–0.05 mm). Residue aggregate micromorphology was determined by scanning electron microscope and energy dispersive X-ray spectroscopy, and the residue aggregate microstructure was determined by synchrotron-based X-ray micro-computed tomography (SR-μCT) and image analysis techniques. Natural regeneration may improve residue aggregate stability and form a stable aggregate structure. Calcium content increased whilst sodium content decreased significantly on the surface of residue aggregates. Under natural soil-forming processes bauxite residue porosity, specific surface area, average length of paths, and average tortuosity of paths all significantly increased. This demonstrated that natural regeneration may stimulate the formation of stable aggregate structure in residues. Further understanding should focus on particle interaction forces and agglomeration mechanisms with the addition of external ameliorations.

Item Type: Article
Keywords: Bauxite residue, Soil-forming processes, Micro-computed tomography, Aggregate microstructure, Pore-throat network
Divisions: Crop and Environment Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 09 Dec 2016 10:27
Last Modified: 23 Jan 2018 12:50
URI: http://hau.collections.crest.ac.uk/id/eprint/14548

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