The droplet test and single-particle charge test show that there is interaction between gangue phases of different charges,and an initial slag with uniform composition is formed finally.The melting of gangue phases with different properties and their interaction mechanism are analyzed by using FactSage thermodynamic calculation software,and the influence of interaction on smelting under different technological conditions is expounded.The results show that the liquid phase ratio of gangue phase of pellets is higher than that of sinter due to its different mineral phase composition.The liquid phase ratio of mixed primary slag composed of pellets and sinter gangue phase is higher than that of single sinter gangue phase and the weighted average of liquid phase ratio of pellets and sinter gangue phase,which shows that the interaction can promote the melting of refractory sinter gangue phase;and the liquid fraction of gangue phase increases with the increase of FeO mass fraction.Under current process conditions,high alkalinity sinter with acid charge is more reasonable than flux type charge.In the future,high reducing potential blast furnaces such as oxygen blast furnace and hydrogen-rich blast furnace can use a large number of acid charge and flux charge.