Cost-effective treatment or even valorization of the bauxite residue (red mud) from the alumina industry is in demand to improve their environmental and economic liabilities. This study proposes a strategy that provides a near-complete conversion of bauxite residue to valuable products. The first step involves dilute acid leaching, which allowed the fractionation of raw residues into (1) an aqueous fraction rich in silica and aluminium and (2) a solid residue rich in iron, titanium and rare earth elements. For the proposed process, 91% of the original silicon, 67% of the aluminium, 78% of the scandium and 69% of the cerium were recovered. The initial cost evaluation suggested that this approach is profitable with a gross margin of 167 $US per tonne. This "Residue2Product" approach should be considered for large-scale practices as one of the most economical and sustainable solutions to this environmental and economic liability for the alumina industry.
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http://dx.doi.org/10.1016/j.jenvman.2024.120751 | DOI Listing |
Materials (Basel)
January 2025
Enalos Research and Development IKE, 15234 Athens, Greece.
This research aimed to investigate the potential of using alkali activation technology to valorize steel slag and bauxite residue for the production of high-performance pavement blocks. By utilizing these industrial by-products, the study seeks to reduce their environmental impact and support the development of sustainable construction materials. Lab-scale testing showed that bauxite pavers showed a decrease in mechanical strength with increasing replacement of ordinary Portland cement.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Laboratory of Sorption Methods, Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, 119991 Moscow, Russia.
The use of reduction leaching in the production of alumina from bauxite by the Bayer process in order to decrease the amount of waste (bauxite residue) by adding elemental iron or aluminum, as well as Fe salts and organic compounds in the stage of high-pressure leaching, requires the purchase of relatively expensive reagents in large quantities. The aim of this study was to investigate the possibility of the use of electrolytically reduced bauxite residue (BR) as a substitute for these reagents. Reduced BR was obtained from Al-goethite containing BR using a bulk cathode in alkaline suspension.
View Article and Find Full Text PDFChemosphere
February 2025
College of Land Science and Technology, China Agricultural University, Beijing, 100193, PR China. Electronic address:
Heavy metals released from metallic sulfidic tailings pose significant environmental threats by contaminating surface and groundwater in mining areas. Sustainable rehabilitation methods are essential to remove or stabilize these metals, improving the quality of acid mine drainage and minimizing pollution. This study examines the adsorption capacity of zinc ions (Zn) by different iron-silicate mineral groups under natural weathering and bacteria-regulated weathered conditions.
View Article and Find Full Text PDFACS Omega
December 2024
Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China.
To immobilize the activity and bioavailability of soil Cd, the single treatment only flooding (F) and the combined treatments with flooding plus bauxite residue (F-B) or lime (F-L) were designed to investigate the impacts of different treatments on the toxicity and bioavailability of Cd in contaminated soil. Compared with the single treatment (F), the combined treatments (F-B and F-L) improved soil-associated organic functional groups and aggregated stability in soil. The average particle sizes of soil aggregates increased from 126 nm (F-treated soil) to 256 and 270 nm following F-B and F-L treatments, respectively.
View Article and Find Full Text PDFAnal Methods
January 2025
School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
C-ZIF-67@PAN nanofibers are prepared as an active material for ampicillin (AMP) detection. Metal organic frameworks (MOFs) can provide larger specific surface area and more binding sites. The PAN fiber in the further carbonization process can make ZIF-67 orderly arranged, enhance the conductivity of the material, and make the response more sensitive.
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