These thermodynamic predictions were confirmed by TGA tests, where the char was fully converted into gas under CO2 or H2O atmosphere because of enough oxygen sources but a low carbon conversion was obtained under inert atmosphere. TGA results further indicated that the reactivity of char with oxygen carrier under steam atmosphere is much higher than that under CO2 atmosphere and the Fe2O3 phase is mainly reduced into Fe3O4 phase in all the tests. Additionally, several other different carriers (Al2O3, NiO-modified iron ore and NiO) were employed to compare the reactivity of iron ore as well. The order of reactivity is speculated as follows: Pure oxygen