Selective Zinc Removal from Electric Arc Furnace (EAF) Dust by Using Microwave Heating

Recycling of electric arc furnace (EAF) dust helps to avoid disposal of wastes, conserves resources, and minimizes its environmental impact. This study aimed to investigate the selective zinc removal from EAF dust by means of microwave heating oven as a heat source. The effect of microwave heating temperature on the selective zinc removal from EAF dust was studied at temperatures of 750 °C, 850 °C, and 950 °C. The mixture of EAF dust and graphite was well homogenized and compressed to pellet and heated for 20 min at the microwave power of 1.1 kW. X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM–EDS) techniques were used to characterize the residue after microwave treatment. The results indicated that the reduction and the recovery of zinc increase with the rising temperatures. The temperature of 750 °C was insufficient for the volatilization of zinc. Zinc removal of 94% was achieved after microwave heating at 950 °C. The residue that remained in the crucible was composed mainly of metallic iron and calcium ferrite. These results indicated that a temperature of 950 °C is suitable for selective removal of zinc from EAF dust, which is in accordance with the thermodynamic calculations.