Rate of Iron Carburization by Carbon in Slags through Carbon/Slag and Slag/Metal Reactions at 1723 K

The carbide capacity of CaO–SiO2–Al2O3 slags and the rate of iron carburization through successive phases of carbon, slag, and metal are measured at 1723 K. The carbide capacity of high-basicity slag is higher than that of simulated blast-furnace (BF) slag. The iron carburization rate through CaO–SiO2–Al2O3 slags is much smaller than the rate of direct carburization or that through slags including iron oxide. It is found that the rate of carburization of iron through slags increases with increasing slag basicity. The apparent rate constant of the carburization reaction is derived to be k = 2.71 × 10–5 mol/(m2 s) for the simulated BF slag and k = 8.00 × 10–5 mol/(m2 s) for the high-basicity slag. The rate increases with increasing slag basicity, increasing carbide capacity, and decreasing oxygen partial pressure.