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<p>The increasing accumulation of bauxite residue (BR) necessitates its comprehensive utilization. This study investigated a route to recover a number of its constituents and consisting of the processes of low-temperature H<sub>2</sub> reduction roasting of BR mixed with NaOH, followed by water leaching, carbonation of the solution, and smelting of the insoluble solids using bio-carbon. Response surface methodology optimized the effects of temperature and time on Al recovery and alumina grade, identifying optimal conditions at 80&#xa0;°C for 120&#xa0;min with a CO<sub>2</sub> flow rate of 25&#xa0;L/h, achieving 96.5% Al recovery and 98.8% alumina grade. Sodium (Na) is present as Na<sub>2</sub>CO<sub>3</sub> in the leach liquor after carbonation and it can be further extracted. The remaining insoluble solids were smelted at the optimized condition of 1650&#xa0;°C with 6&#xa0;wt% CaO and 20&#xa0;wt% bio-carbon, achieving 97% Fe recovery and 96% Fe grade, ensuring efficient slag–metal separation and high-quality pig iron production. This method can offer a promising path toward an integrated and sustainable utilization of BR, with the remaining challenges identified.</p> Graphical Abstract <p></p>

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Toward an Integrated and Sustainable Bauxite Residue Valorization, Employing H2 Reduction Roasting, Carbonation, and Bio-carbon Smelting

  • 期刊论文

  • 发表日期：

    2025年4月11日

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  • Ganesh Pilla,
  • Tobias Hertel,
  • Yiannis Pontikes

摘要

The increasing accumulation of bauxite residue (BR) necessitates its comprehensive utilization. This study investigated a route to recover a number of its constituents and consisting of the processes of low-temperature H2 reduction roasting of BR mixed with NaOH, followed by water leaching, carbonation of the solution, and smelting of the insoluble solids using bio-carbon. Response surface methodology optimized the effects of temperature and time on Al recovery and alumina grade, identifying optimal conditions at 80 °C for 120 min with a CO2 flow rate of 25 L/h, achieving 96.5% Al recovery and 98.8% alumina grade. Sodium (Na) is present as Na2CO3 in the leach liquor after carbonation and it can be further extracted. The remaining insoluble solids were smelted at the optimized condition of 1650 °C with 6 wt% CaO and 20 wt% bio-carbon, achieving 97% Fe recovery and 96% Fe grade, ensuring efficient slag–metal separation and high-quality pig iron production. This method can offer a promising path toward an integrated and sustainable utilization of BR, with the remaining challenges identified.

Graphical Abstract