Abstract
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.
Highlights
Electric arc furnace (EAF) dust is a byproduct waste generated by the secondary steelmaking process in an electric arc furnace and considered as a hazardous material in most industrialized countries [1, 2]
The present study examined the possibility of selective zinc removal from EAF dust by means of microwave heating
The microwave heating tests indicated that EAF dusts are good microwave absorbers owing to the contents of carbon and iron oxides
Summary
Electric arc furnace (EAF) dust is a byproduct waste generated by the secondary steelmaking process in an electric arc furnace and considered as a hazardous material in most industrialized countries [1, 2]. EAF dust contains valuable metals such as iron, zinc, and chromium in addition to variable amounts of calcium, manganese, magnesium, and silicon [3]. Zinc represents the major element of the EAF dust, and its value varies between 7 and 40 wt%, depending on scrap used, and the ratio of galvanized scrap utilized [4,5,6]. The reuse of the dusts is limited due to high Zn contents in the dusts. The contributing editor for this article was I.
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