Microstructure change of V-Ti magnetite concentrate pellets during reduction

The reduction process of V-Ti magnetite concentrate pellets was studied under the simulated condition of blast furnaces. Phase compositions in the pellets at different reduction temperatures were determined by X-ray diffraction analysis. The microstructure change of the pellets during reduction was observed by optical microscopy and scanning electron microscopy. The distribution of different elements in oxides was identified by energy dispersive spectrometry. It is found that iron-titanium segregation in the pellets during reduction affects the reducibility of the pellets, and the formed ilmenite spar of high titanium content increases the difficulty in reduction of iron oxides. The dense iron shell formed at high temperature hinders the reduction of inner oxides, leads to stagnation of reduction, and makes the reducibility of the pellets poor at high temperature. When the inner liquid melt dripping down, the oxygen potential increases in the lower part of the blast furnace, which decreases the generation of Ti(C, N).