Microstructure change of V-Ti magnetite concentrate pellets during reduction
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摘要: 在实验室模拟高炉条件下研究了含钒钛铁矿球团的还原过程,采用X射线衍射仪测定含钒钛铁矿球团在不同还原温度下的物相组成,通过光学显微镜和扫描电镜观察含钒钛铁矿球团还原过程中微观结构变化,并结合能谱分析仪研究氧化物中不同元素的分布状况.含钒钛铁矿球团在还原过程中出现的铁钛分离现象会影响含钒钛铁矿球团的还原性,形成的高钛含量钛铁晶石会增加铁氧化物还原难度.高温时形成的密实金属铁球壳会阻碍内部氧化物的还原,导致还原停滞,从而造成含钒钛铁矿球团高温还原性较差.当内部熔融物滴下时,会提高高炉下部氧势,有利于减少Ti(C,N)的生成.Abstract: 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).
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Keywords:
- magnetite /
- ore pellets /
- ore reduction /
- microstructure /
- phase composition /
- blast furnaces
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