The reduction behavior of composite pellets comprising of iron oxide and synthetic graphite was examined using a Thermogravimetric Analyzer (TGA) at a range of temperatures under inert conditions. An IR analyzer was used to measure the off-gas compositions and the kinetics of iron oxide reduction. As expected, under isothermal conditions, the reduction rates increased with increasing reduction temperature. The carbon content of the composite was seen to influence the reduction rate, such that increasing molar ratio of C/O increased the reaction rate, and decreased the initiation of the reduction temperature. The molar ratio of composite pellets affected the residual carbon content of the composite, and this in turn influenced the carburization rate particularly at temperatures exceeding 1200°C. A similar trend was also observed during composite reduction under non-isothermal conditions, except for the extent of carburization being greater at lower temperatures. This study suggests that the reduction and carburization temperatures, as well as the melting temperatures could be controlled by optimizing the iron ore to carbon ratio in the composite pellet.
