Abstract:Mixing enthalpy and Gibbs free energy of Mg-Ti, Mg-Fe, Ti-Fe binary systems, and Mg-Ti-Fe ternary system were calculated based on Miedema Model and Troop Extension Model. The results show that, for Mg-Ti-Fe ternary system, in low Mg content zone, calculation values of mixing enthalpy and Gibbs free energy are negative, which demonstrates that Fe atom and Ti atom have stronger chemical driving force by comparison with Mg atom. During reduction stage of titanium sponge production, Fe impurity inflows mainly come from stainless reactor. Upon dissolving in liquid magnesium, Fe atom will form intermetallic compound with titanium atom at reaction zone priority, and enrich near reactor wall.