Effect of Carbonaceous Material Surface Texture on Iron Carburization Reaction under Loading Condition

Scrap melting process is one of biggest energy required process in the ironmaking process with EAF. Carbon based scrap melting process has a potential problem about CO2 emission. An aim of this study is finding an optimal surface texture of carbon source for scarp melting with reaction acceleration. Combinations between pure iron cylindrical block and several kinds of carbonaceous materials were evaluated with isothermal condition at 1673 K and keeping contact each other with loading condition. In order to avoid effect from object lower temperature range, rapid heating and quenching condition was applied to reach to 1673 K. As different surface texture carbonaceous material’s samples, coke, charcoal from eucalyptus and graphite were prepared. The coke needed obvious longer time to melt iron sample than other carbonaceous materials. It is indicated that coke ash has an obvious effect to prevent carbon transportation at reaction interface. Although charcoal has a better carbon structure for carburization reaction than graphite, the charcoal showed almost similar time for the melting as graphite. An effective contact area on interface of iron and carbon samples was estimated from surface observation by laser microscope and SEM-EDS. The effective area was decreased by existing of ash, porosity, and roughness. Decreasing of the effective contact area had obvious effect on carburization reaction as melting start temperature rising.