Fresh water leaching of alkaline bauxite residue after sea water neutralization

Menzies, Neal W., Fulton, Ian M., Kopittke, Rosemary A. and Kopittke, Peter M. (2009) Fresh water leaching of alkaline bauxite residue after sea water neutralization. Journal of Environmental Quality, 38 5: 2050-2057. doi:10.2134/jeq2008.0511


Author Menzies, Neal W.
Fulton, Ian M.
Kopittke, Rosemary A.
Kopittke, Peter M.
Title Fresh water leaching of alkaline bauxite residue after sea water neutralization
Journal name Journal of Environmental Quality   Check publisher's open access policy
ISSN 0047-2425
1537-2537
Publication date 2009-08
Year available 2009
Sub-type Article (original research)
DOI 10.2134/jeq2008.0511
Open Access Status
Volume 38
Issue 5
Start page 2050
End page 2057
Total pages 8
Editor Gary Pierzynski
Susan Ernst
Place of publication Madison, WI, U.S.A.
Publisher American Society of Agronomy
Collection year 2010
Language eng
Subject C1
961202 Rehabilitation of Degraded Farmland, Arable Cropland and Permanent Cropland Environments
050304 Soil Chemistry (excl. Carbon Sequestration Science)
05 Environmental Sciences
06 Biological Sciences
07 Agricultural and Veterinary Sciences
Formatted abstract
Processing of bauxite to extract alumina produces a strongly alkaline waste, bauxite refining residue, which is commonly stored in engineered structures. Once full, these waste dumps must be revegetated. In many alumina refineries, the waste is separated into fine-textured red mud and coarse-textured residue sand (RS). The sand component has physical characteristics that make it a suitable plant growth medium, provided the adverse chemical characteristics can be addressed. Neutralization of the highly saline-sodic RS with sea water lowers pH, reduces Na saturation, and adds plant nutrients. However, sea water-neutralized RS remains saline sodic and needs fresh water leaching before use as a plant growth medium. Columns containing sea water-neutralized RS were leached with 30 m depth-equivalent of fresh water to evaluate the effects of rainfall on the RS and its leachate. Entrained cations were rapidly displaced by the fresh water, lowering salinity to non-plant-limiting levels (≤0.3 dS m-1). The percentage of the effective cation exchange capacity (ECEC) saturated by Na decreased from 71 to 62% due to a reduction in soil solution ionic strength (causing a decrease in the ECEC) and the preferential displacement of Na+ (and K +) from the exchange. Fresh water leaching increased pH (leachate pH increased from 8.0 to 10.1). This pH increase is attributed to the slow dissolution of the Na-containing mineral sodalite. Under the current experimental conditions, the application of 30 m depth-equivalent of leaching reduced the total RS sodalite content by <10%.
Copyright © 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.
Keyword Sandy soils
Red mud
pH
Deficiency
Capacity
Q-Index Code C1
Q-Index Status Confirmed Code
Additional Notes Author prepress title: "Freshwater leaching of alkaline bauxite residue following seawater neutralization".

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Agriculture and Food Sciences
 
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Citation counts: TR Web of Science Citation Count  Cited 10 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 07 Apr 2010, 12:47:50 EST by Kaye Hunt on behalf of School of Land, Crop and Food Sciences