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<p>Primary aluminum dross (PAD) is a chemically complex by-product of aluminum smelting, whose fine, non-metallic fraction contains minimal recoverable metal yet substantial amounts of reactive aluminum compounds, making it both an environmental liability and a potential secondary resource. This study presents a selective alkaline upcycling strategy to convert PAD into high-purity mesoporous gibbsite (Al(OH)<sub>3</sub>) and ammonia via controlled leaching and precipitation. Mineralogical analysis of the − 0.8&#xa0;mm fraction reveals a matrix dominated by corundum (21.8 wt.%), aluminum nitride (16.4 wt.%), γ-Al<sub>2</sub>O<sub>3</sub> (7.3 wt.%), and spinel phases, conferring high chemical reactivity. Comparative leaching study using distilled water, 6.2&#xa0;M NaOH, and 6.2&#xa0;M HCl demonstrates that AlN hydrolysis controls both gas evolution and solution chemistry, with NH<sub>3</sub> release rising from 0.36&#xa0;mL&#xa0;g<sup>−1</sup> in water to ~ 11&#xa0;mL&#xa0;g<sup>−1</sup> in alkaline and acidic media. Only NaOH leaching produces an aluminate solution with an aluminum concentrations of ~ 46&#xa0;g L<sup>−1</sup>, from which controlled precipitation yields single-phase gibbsite. The dried gibbsite exhibits ~ 99.0 wt.% purity, ~ 29&#xa0;nm crystallite size, and 201 m<sup>2</sup>/g SBET, showing a Type-IV adsorption–desorption isotherm with narrow mesopores centered at ~ 4.9&#xa0;nm. These results demonstrate the feasibility of circular upcycling of PAD into high-value, mesoporous gibbsite suitable for advanced applications.</p>

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Upcycling of Primary Aluminum Dross into High-Purity Mesoporous Potential Catalytic Precursor Gibbsite and Ammonia: A Comparative Study Using Different Leaching Agents

  • 期刊论文

  • 发表日期：

    2026年4月22日

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  • Ahmed S. Aadli,
  • Nora M. A. Elebiary,
  • Manal S. Ebaid

摘要

Primary aluminum dross (PAD) is a chemically complex by-product of aluminum smelting, whose fine, non-metallic fraction contains minimal recoverable metal yet substantial amounts of reactive aluminum compounds, making it both an environmental liability and a potential secondary resource. This study presents a selective alkaline upcycling strategy to convert PAD into high-purity mesoporous gibbsite (Al(OH)3) and ammonia via controlled leaching and precipitation. Mineralogical analysis of the − 0.8 mm fraction reveals a matrix dominated by corundum (21.8 wt.%), aluminum nitride (16.4 wt.%), γ-Al2O3 (7.3 wt.%), and spinel phases, conferring high chemical reactivity. Comparative leaching study using distilled water, 6.2 M NaOH, and 6.2 M HCl demonstrates that AlN hydrolysis controls both gas evolution and solution chemistry, with NH3 release rising from 0.36 mL g−1 in water to ~ 11 mL g−1 in alkaline and acidic media. Only NaOH leaching produces an aluminate solution with an aluminum concentrations of ~ 46 g L−1, from which controlled precipitation yields single-phase gibbsite. The dried gibbsite exhibits ~ 99.0 wt.% purity, ~ 29 nm crystallite size, and 201 m2/g SBET, showing a Type-IV adsorption–desorption isotherm with narrow mesopores centered at ~ 4.9 nm. These results demonstrate the feasibility of circular upcycling of PAD into high-value, mesoporous gibbsite suitable for advanced applications.