HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Menzies, N. W. Articles by Morrell, W. J. Search for Related Content PubMed PubMed Citation Articles by Menzies, N. W. Articles by Morrell, W. J. Agricola Articles by Menzies, N. W. Articles by Morrell, W. J. Related Collections Soil Chemistry Industrial Waste

TECHNICAL REPORTS

Waste Management

Seawater Neutralization of Alkaline Bauxite Residue and Implications for Revegetation

^a Centre for Mined Land Rehabilitation, University of Queensland, St. Lucia 4072, QLD, Australia
^b Alcan Gove Pty Ltd, Nhulunbuy 0881, NT, Australia

^* Corresponding author (n.menzies{at}uq.edu.au).

Received for publication September 1, 2003. Reaction of bauxite residue with seawater results in neutralization of alkalinity through precipitation of Mg-, Ca-, and Al-hydroxide and carbonate minerals. In batch studies, the initial pH neutralization reaction was rapid (<5 min), with further reaction continuing to reduce pH for several weeks. Reaction with seawater produced a residue pH of 8 to 8.5. Laboratory leaching column studies were undertaken to provide information on seawater neutralization of the coarse-textured fraction of the waste, residue sand (RS), under conditions comparable with those that might be applied in the field. An 0.80-m-deep column of RS was neutralized by the application of the equivalent of 2-m depth of seawater. In addition to lowering the pH and Na content of the residue, seawater neutralization resulted in the addition of substantial amounts of the plant nutrients Ca, Mg, and K to the profile. Similar results were also obtained from a field-scale assessment of neutralization. However, the accumulation of precipitate, consisting of hydrotalcite, aragonite, and pyroaurite, in the drainage system may preclude the use of in situ seawater neutralization as a routine rehabilitation practice. Following seawater neutralization, RS remains too saline to support plant growth and would require fresh water leaching before revegetation.

Abbreviations: EC, electrical conductivity • ICP–AES, inductively coupled plasma atomic emission spectroscopy • RM, red mud • RS, residue sand

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2004 33: 1589-1599. [Full Text]