Preparing high-quality vanadium titano-magnetite pellets for large-scale blast furnaces as ironmaking burden

摘要

The oxidation behaviour and the phase and microstructure evolution of VTM (vanadium titano-magnetite) pellets were studied during thermal processing in order to optimise the production method for producing high-quality pellets. The oxidation tests showed that titanium magnetite and ilmenite in VTM began to oxidise at 500 degrees C and 700 degrees C, respectively. When the temperature reached 875 degrees C, VTM was mainly oxidised to Fe2O3, while Fe2TiO5 was the main oxidation product when the temperature reached 1050 degrees C. The consolidation of the pellets was affected by the degree of oxidation and the oxidation products. Results indicated that the most suitable oxidation ratio was about 70%, and the preferred mineral phase was recrystallised Fe2O3, which was beneficial to improving pellet consolidation in roasting process. The most appropriate oxidation condition was 875 degrees C for 12 min, which contributed to forming more Fe2O3 phase, and the compressive strength of roasted pellet reached 2939 N. The pellets could be used as a high quality ironmaking burden for large-scale blast furnaces.