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本文对太和钒钛磁铁精矿加钠和不加钠焙烧球团的还原膨胀进行了研究。两类球团的主要物相组成均为赤铁矿和铁板钛矿。低温还原过程中,球团的膨胀主要发生于赤铁矿向磁铁矿的还原阶段。通过测试发现,还原球团中磁铁矿的微区应力随赤铁矿钛固溶量的增加而增大。由于钠盐的作用,钠球赤铁矿的钛固溶量较同温度焙烧的白球的要高1％,因此钠球还原球团的微区应力较大。俄歇谱分析表明,钠球中,元素Na、V、Si在晶界偏析,这造成球团晶间强度的大大降低。由于强度的降低和微区应力的增大,钠球在低温还原时,结构严重破坏,产生异常的还原膨胀。
In this paper, the reduction and expansion of Taihe vanadium-titanium magnetite concentrate plus sodium and sodium-free roasted pellets were studied. The main phase composition of the two types of pellets are hematite and tantalite. During the low temperature reduction, the expansion of pellets mainly occurs during the reduction of hematite to magnetite. Through the test, it is found that the micro-area stress of magnetite in reducing pellets increases with the increase of the amount of hematite titanium solute. Due to the effect of sodium salt, sodium titanium hematite titanium solid solution than the same temperature roasted white ball to 1% higher, so sodium ball reduction pellet micro-zone stress. Auger spectroscopy analysis shows that the Na elements, Na, V, Si segregation in the grain boundary, which resulted in greatly reduced the intergranular strength of the pellets. Due to the decrease of the strength and the increase of the stress in the micro zone, the sodium ball severely damaged the structure and produced abnormal reduction and expansion when it was reduced at low temperature.