A self-reduction process for collaborative resource utilization of electric arc furnace dust and waste activated carbon: Adjusting basicity to enhance Zn/Pb/Fe recovery.

Direct reduction has been considered a promising method for co-processing electric arc furnace dust (EAFD) and waste activated carbon (WAC), but its efficiency is limited by the difficulty in separating zinc and lead from silicates and ferrites. In this study, CaO was employed to adjust the system's basicity (CaO/SiO2), aiming to facilitate the transformation of hardly reducible ferrites and silicates into more reducible ZnO and PbO. These oxides were subsequently reduced and volatilized into the flue gas for recovery. Meanwhile, iron compounds were reduced to metallic iron, which was later recovered via magnetic separation. The results indicated that the recovery efficiency of Zn, Pb and Fe was enhanced by 15.13%, 23.68%, and 2.33%, respectively, compared to the traditional process. Additionally, the roasting temperature was lowered by 100 °C. The change of the chemical composition in the system led to a decrease in liquid phase formation from 15.47% to 0% during phase reconstruction. This effectively addressed the critical issue of kiln ringing, which is vital to ensuring uninterrupted industrial production. The process also provides a sustainable approach to industrial solid waste management, mitigating environmental risks while advancing resource circularity.