Reduction of iron oxides by nano-sized graphite particles observed in pre-oxidized iron carbide at temperatures around 873 K

Abstract

Iron oxides containing nano-sized graphite particles were prepared from porous iron carbide and reaction characteristics of the oxides/ graphite composite mixture were investigated by thermogravimetry in combination with microstructure analysis using X-ray diffractometry and optical microscopy. A drastic mass reduction was observed in a temperature range between 833 K and 1023 K, and the loss of mass reached 2.8%. The mass reduction was found to correspond to a growth of Fe and FeO at the expense of Fe3O 4 and Fe2O3 in the composite mixture, suggesting that the oxides were reduced by graphite. The oxides-graphite reaction is presumably indirect reduction caused by CO and H2 that are generated through the water gas reaction, C + H2O → CO + H2.