Carbon Dissolution Occurring during Graphite–Ferrosilicon Interactions at 1550°C

Abstract

The carburisation reaction is a key reaction for the cupola process, since the metallic liquid droplets interact with coke at high temperatures. The kinetic mechanism of carbon dissolution in liquid iron had been extensively investigated. However, there is little knowledge about the kinetics of carbon dissolution when the silicon contents are over 10%, since the silicon content during the iron and steel making processes are usually well below this limit.
Carbon dissolution phenomenon and associated mechanisms are established for ferrosilicon alloys and silicon at 1550°C in this study. The overall-rate constants at 1550°C for Si 98.5%, FeSi 74% and FeSi 24.7% were 3.8, 3 and 3.9×10⁻³ (s⁻¹) respectively. The appearance of SiC as an interfacial product was found during the metal–graphite interactions and its role as a retarding agent during the carbon pickup was established.
The kinetics of carbon dissolution from graphite is controlled by a mixed-control mechanism and this includes the diffusion of carbon and carbon transfer from the SiC interfacial layer.