Influence of Aluminum-Carbon Composite Pellets on FeO Reduction and Iron Recovery from Electric Arc Furnace Slag

Abstract

We investigated the effect of Al-C composite pellets (ACCP) on the reduction behavior of FeO in electric arc furnace (EAF) slag and the iron recovery at different n(Al)/(n(Al)+n(C)) at 1823K (1550 degrees C). A carbothermic reaction was the dominant process at n(Al)/(n(Al)+n(C)) <0.4, whereas aluminothermic reduction was the major process at n(Al)/(n(Al)+n(C)) >0.6; these observations are based on the final content of FeO and Al2O3 in the molten slag. The aluminum and carbon present in the ACCP competitively affected the reaction stoichiometry (i.e., the material balance) between the production of CO+Al2O3 and the consumption of FeO. Iron recovery increased up to a yield of approx. 90 pct as the n(Al)/(n(Al)+n(C)) ratio increased. Because Al in the ACCP readily reacts to reduce FeO in the molten slag, iron recovery is proportional to the n(Al)/(n(Al)+n(C)) ratio. The precipitation of solid compounds in the slag phase, such as monoxide ([Mg,Fe] O ) and spinel (MgO Al 2O3), occurred during FeO reduction; this was experimentally confirmed as well as by thermochemical computation. Furthermore, we proposed a schematic reaction mechanism in the present study.