Influence of Aluminum-Carbon Composite Pellets on FeO Reduction and Iron Recovery from Electric Arc Furnace Slag
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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 nAl/(nAl + nC) at 1823 K (1550 °C). A carbothermic reaction was the dominant process at nAl/(nAl + nC) < 0.4, whereas aluminothermic reduction was the major process at nAl/(nAl + nC) > 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 nAl/(nAl + nC) ratio increased. Because Al in the ACCP readily reacts to reduce FeO in the molten slag, iron recovery is proportional to the nAl/(nAl + nC) ratio. The precipitation of solid compounds in the slag phase, such as monoxide ([Mg,Fe]·O) and spinel (MgO·Al2O3), 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.
This work was partly supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant (Grant number 20172010106310) and by Korea Evaluation Institute of Industrial Technology (KEIT) grant (Grant number 10062469) funded by the Ministry of Trade, Industry & Energy (MOTIE), Korea.
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