Abstract: The vanadium titano-magnetite slag from Chengde iron & steel company is characterized by high viscosity,difficult in separation of the slag-iron higher hardness.The study has been done to decrease the viscosity and hardness of the vanadium titano-magnetite slag.The results show that the viscosity decreases from 1.632 Pa·s to 0.880 Pa·s with the additive amount of CaF₂ increasing.The viscosity first decreases from 1.632 Pa·s to 1.104 Pa·s and then increases from 1.104 Pa·s to 1.296 Pa·s with the additive a-mount of precipitator dust increasing.The viscosity first decreases from 1.632 Pa·s to 1.024 Pa·s and then increases from 1.024 Pa·s to 1.664 Pa·s with the additive amount of coal fly ash increasing.Among the three cooling strategies of water-cooling,quenching and slow cooling,the precipitated amount of perovskite increases with the rate of cooling decreasing.Under the water-cooling condition,for both of original slag and with 2% coal fly ash,the precipitation area of perovskite is small,but the precipitation area of perovskite in the slag with CaF₂ addition is big.Under the quenching condition,the precipitated amount and the crystal size of perovskite increases with the additive amount of CaF₂ increasing,while the precipitated amount of perovskite decreases with the addition of 2% coal fly ash.Under the slow cooling condition,the precipitated amount and the crystal size of perovskite increases with the additive amount of CaF₂ increasing,while the precipitated amount of perovskite changes a little with the addition of 2% coal fly ash.