Self-reduction of Core-Shell EAF Dust-Biochar Composite Pellets Under Microwave Irradiation

Abstract

Electric arc furnace (EAF) dust is an important secondary resource from which valuable elements can be recovered. The recovery process can be intensified by the self-reduction of core-shell EAF dust-biochar composite pellets under microwave irradiation. In this study, the effects of various parameters on reduction of the core-shell EAF dust-biochar composite pellets in N2 were explored. It was demonstrated that under the optimal conditions of reduction temperature of 1050 °C, dwell time of 20 min, total C/Fe mass ratio of 0.24, C/Fe mass ratio of pellet core of 0.30, and diameter of pellet core of 6–8 mm, the resulting metallized pellets had total iron content of 70.13 wt %, iron metallization degree of 97.97%, volatilization percentage of zinc of 99.52%, volatilization percentage of lead of 98.49%, manganese content of 2.83 wt % and chromium content of 0.22 wt %. The great reduction performance was attributed to strong gasification of carbon in association with selective distribution of biochar in the composite pellets with good microwave absorption.