2010 Volume 96 Issue 11 Pages 646-653
In order to improve the metallic iron (M.Fe) productivity of partially reduced agglomerates production in packed bed with air flow, the packed bed of which the carbon composite iron ore green balls were charged lower side and the ordinary raw materials are charged on them, called lower charging, were examined. The M.Fe productivity of lower charging were compared with that of the packed bed in which the carbon composite iron ore green balls were mixed with the ordinary raw materials and charged, called mixed charging. Also, the effect of exhaust gas velocity during sintering was studied. As a result, the M.Fe productivity of lower charging was higher than that of mixed charging because reduced agglomerates placed upper side of the packed bed were easier to be re-oxidized. In addition, when the exhaust gas velocity was too slow, the time for re-oxidization was extended so that the M.Fe productivity decreased. However, when the exhaust gas velocity was too fast, the excess of free C combustion or re-oxidization of reduced agglomerates was caused so that the M.Fe productivity decreased, too. Therefore, there is a exhaust gas velocity which make the M.Fe productivity be highest. In this study, the M.Fe productivity achieved 0.21 M.Fe-t/m2/h with lower charging and 0.19 Nm/s of exhaust gas velocity.
