Novel Strategy\nfor Efficient Recovery of CuO-Based\nMultiple-Metals from Copper Smelter Dust toward CO<sub>2</sub> Electrocatalytic\nReduction

Copper smelter dust, a typical hazardous waste that is\nabundant\nin valuable heavy metals, holds the potential to be regarded as a\npromising resource. This study introduces a new approach that integrates\nchlorination roasting and cascade condensation to efficiently recover\nheavy metals from copper smelter dust. The findings demonstrate the\nsuccessful separation of heavy metals (Cu, Pb, and Zn) as chlorides\nat nearly 100% efficiency while also effectively converting trivalent\narsenic (As(III)) into pentavalent arsenic (As(V)) and immobilizing\nit in the roasting residues, thereby reducing environmental risk.\nThrough the utilization of thermogravimetric mass spectrum analysis\nand thermodynamic equilibrium calculations, the chlorination process\nfor heavy metals was investigated, revealing both direct and indirect\nchlorination processes. Additionally, the study resulted in the development\nof a CuO-based multiple-metals electrocatalyst from the oxidized roasting-recovered\nheavy metal chlorides, exhibiting significantly enhanced catalytic\nactivity and faradaic efficiency for the electroreduction of CO<sub>2</sub> into CO and CH<sub>4</sub> compared to pure CuO electrocatalyst\nunder similar electrocatalytic conditions. Overall, this work presents\na sustainable and scalable method and new insights for addressing\nenvironmental risks while repurposing copper smelter dust.