THERMODYNAMIC STUDY OF CEMENTITE FORMATION IN Fe-C-O-H SYSTEM

摘要

In general, due to the failure in the formation of Wustite (FeO) in reduction process at temperatures less than 6I7aC, Magnetite (Fe_3O_4) can be reduced and carburized at one stage and be directly changed into Cementite (Fe^C). In this study, the effect of temperature, pressure, and chemical combination on the formation of Fe_3C from iron oxides is investigated thermodynamically by plotting triple-diagrams (C-H-O). In fact, the thcrmo-dynamic calculations were performed for the formation of Fe_3Cfrom iron oxides under an atmosphere containing CH_4, CO_2, CO, H_2O, and II2; pressures ranging from 0.1 to 10 atm; and especially within a temperature ranging from 300 to 617" C. Finally, the results obtained from the thermodynamic calculations in this area showed that the conditions for the formation ofFejCfrom Fe_3O_4 at one stage were facilitated by enriching the atmosphere with carbon monoxide and conversely were weakened by its enrichment with methane. Also, the most suitable conditions for the formation were determined to be a temperature ranging from 427 to 617aC at pressures ranging from 1 to 3 atm.