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IJESD 2018 Vol.9(12): 375-379 ISSN: 2010-0264
doi: 10.18178/ijesd.2018.9.12.1132
doi: 10.18178/ijesd.2018.9.12.1132
Effects of Leaching on the Chemical and Physical Properties of Bauxite Residue Mud and Sand
Y. Li, R. J. Haynes, and Y.-F. Zhou
Abstract—The major mineralogical constituents for residue mud and sand were amorphous material 34 and 23%, goethite 22 and 10% and quartz 7.1 and 48% respectively. Mixtures consisting of 0:100, 25:75, 50:50, 75:25 and 100:0% v/v residue mud: residue sand were incubated for four weeks and a portion was then leached bi-weekly for another 14 weeks. Residue sand had a much lower EC, exchangeable Na, ESP and short-term and residual acid neutralizing capacity than mud. Leaching caused a decrease in the EC of residues by at least one order of magnitude and ammonium acetate-extractable Na levels were reduced by more than half. The pH of the residue decreased by about one unit after leaching. This was attributed to leaching of soluble alkalinity (HCO3-/CO32) with the mobile Na+ ion. Both short-term and residual acid neutralizing capacity were lowered following leaching. The macroporosity of sand was much greater than that of mud whilst available water holding capacity was greater for mud. Adding increasing proportions of mud to sand decreased macroporosity and increased available water but also increased EC, soluble and exchangeable Na, ESP and acid neutralizing capacity. If mud were to be added to sand prior to revegetation more consideration would need to be directed towards management of chemical constraints to plant growth.
Index Terms—Bauxite processing mud, bauxite processing residue, red mud, red sand, leaching.
Y. Li and R. J. Haynes are with the School of Agriculture and Food Sciences/CRC CARE, The University of Queensland, St Lucia, Queensland 4027, Australia (e-mail: y.li27@uq.edu.au, r.haynes1@uq.edu.au).
Y.-F. Zhou is with the School of Medical Engineering, Foshan University, Guangzhou, China (e-mail: y.zhou3@uq.edu.au).
Index Terms—Bauxite processing mud, bauxite processing residue, red mud, red sand, leaching.
Y. Li and R. J. Haynes are with the School of Agriculture and Food Sciences/CRC CARE, The University of Queensland, St Lucia, Queensland 4027, Australia (e-mail: y.li27@uq.edu.au, r.haynes1@uq.edu.au).
Y.-F. Zhou is with the School of Medical Engineering, Foshan University, Guangzhou, China (e-mail: y.zhou3@uq.edu.au).
Cite: Y. Li, R. J. Haynes, and Y.-F. Zhou, "Effects of Leaching on the Chemical and Physical Properties of Bauxite Residue Mud and Sand," International Journal of Environmental Science and Development vol. 9, no. 12, pp. 375-379, 2018.
