Abstract: Effects of MgO content in sinter on softening-dripping behavior of vanadium-titanium magnetite composite burden and the migration patterns of V， Cr in slag-iron were studied. The results showed that with the increasing of MgO in sinter， the softening range t₄₀-t₄ tends to be wider，the melting range t_D-t_S is narrowed slightly. The cohesive zone tends to be narrow and its location is shifted down but not obvious. Softening-dripping characteristics S decreases at first then increases， the permeability tends to be better then worse， when the content of MgO is between 2.98% and 3.40%， the permeability is the best. The dripping ratio tends to be declining; when MgO is increased， it is not conducive to the reduction of V， Cr. The optimal content of MgO in the sinter is around 3.40% and the content of MgO in BF slag is about 12%.

Key words: BF smelting, vanadium-titanium magnetite, MgO, softening-dripping behavior, the reduction of V, Cr