Differences of softening and melting behavior for vanadium- titanium burden under blast furnace and OY furnace conditions

Vanadium-titanium magnetite is a mineral resource with great economic value and strategic significance. At present,its main processing method is the blast furnace-converter technology in current. This method has many disadvantages,such as high energy consumption,difficult operation and low resource utilization. There is an urgent need to develop a new extraction and separation technology valuable element for vanadium-titanium magnetite. OY furnace is a kind of melting reduction ironmaking process optimized based on COREX. It has the potential advantages of smelting vanadium-titanium magnetite such as pure O₂ injection and lower burden load. The differences of softening and melting behavior of vanadium-titanium burden between blast furnace (BF) and OY furnace (OYF) were researched. The results showed that the softening shrinkage rate of DRI under OYF conditions was smaller duo to lower burden load than BF conditions. The DRI under OYF conditions was maintained a good morphology even at 1 450 ℃,and its temperature range of melting and dropping was declined by 79 ℃ compared with that in BF conditions. Moreover,the pressure drop of vanadium-titanium burden under blast furnace condition rises sharply twice due to the melting of slag and iron,and the foaming of slag,showing the characteristics of "multiple increases". The pressure drop of DRI under OYF conditions did not increase from melting to dropping,showing the characteristics of "single increases". Although the phenomenon of slag foaming appeared in the high temperature zone,namely dropping zone of both BF and OYF,the N₂-free reducing atmosphere in the OYF inhibited the formation of high melting point phase Ti(C,N). The theoretical generation temperature of TiC in OYF is 1 481 ℃,the theoretical generation temperature of Ti(C,N) in BF is only 1 219 ℃. This study prove that the conditions of OYF improve the gas and liquid permeability of the vanadium-titanium burden,weaken the slag foaming,and are favorable for the smelting of vanadium-titanium magnetite.