The gasification reactivities of four pretreated carbonaceous materials from the Corex furnace, including one coal char, two metallurgical cokes, and one recycling dust, were investigated by a thermogravimetric analyzer, in which the recycling dust came mainly from two metallurgical cokes and accounted for a mass fraction of 71.3%. The physicochemical properties of the different samples were tested systematically. The results showed that the recycling dust had a gasification reactivity similar to the coal char, of which the value was higher than those of the two metallurgical cokes. The structure analysis ascertained that the main factor that affected the gasification reactivity was the carbonaceous structure. Moreover, to characterize the reactive behavior of the different samples, three nth-order typical gas-solid reaction models were employed in this study. It has been found that the random pore model was the best model. The activation energies of different chars were in the range of 181.1-202.3 kJ/mol.