Transforming aluminium waste: sustainable conversion to commercial MOFs, hydrogen fuel, and essential aluminium feedstocks

Abstract

Aluminium dross waste is generated during the aluminium smelting process and has an annual production of nearly 5.3 M tonnes worldwide. It is largely comprised of aluminium but also contains different metal oxides, silicates, and other impurities. We demonstrate how to make use of dross by producing high-value products (hydrogen gas, aluminium formate, aluminium acetate, aluminium hydroxide, MOF-303, Al-Fum) towards decarbonization of the aluminium industry. We produce hydrogen gas (1.1–1.2 L g⁻¹ of dross) by digesting it with NaOH, while further outlining methods to upcycle this encased aluminium into high value materials, and identify a route to pure amporhous Al₂O₃via aluminium formate or aluminium acetate. We also demonstrate the production of the water harvesing MOF-303 and Al-Fum directly from processed dross as the aluminium source. This study highlights a complete overview of upcycling of aluminium dross to high value products towards a green energy shift, and industrial circircular economy.