预氧化对岩矿型钛铁矿还原行为的作用机理研究

Study on the Action Mechanism of Pre-oxidation on Reduction Behavior of Rock Ilmenite

以攀枝花钛铁矿为试验对象,详细研究了预氧化对岩矿型钛铁矿还原行为的作用机理。结果表明,未处理的岩矿型钛铁矿的还原速率较慢,而预氧化能够有效提高还原速率。这是因为在预氧化矿还原前期会发生Fe^(3+)→Fe^(2+)(FeTiO_3)的快速转变反应。该反应会生成大量孔洞,破坏了钛铁矿的致密结构,有利于后续还原反应的进行。预氧化焙烧温度越高,焙烧时间越长,钛铁矿的还原速率越快。此外,预氧化还会使后续还原产生的金属Fe晶粒变小,分布变弥散。

Reduction is the key technological process of preparing titanium-rich material from ilmenite. This paper studied the action mechanism of pre-oxidation on reduction behavior of rock ilmenite in detail, using Panzhihua ilmenite as the experimental subject. The results show that the reduction rate of untreated rock ilmenite is slow and the pre-oxidation can increase the reduction rate effectively. This is due to the rapid transformation reaction of Fe3＋→Fe2＋（FeTiO3） at the earlier stage of reduction for pre-oxidized il- menites. This rapid reaction produces a large number of pores and destroys the dense structure of ilmen- ite,which is conducive to the proceeding of reduction reaction. The rate of subsequent reduction of ilmen- ite is greater with higher pre-oxidation temperature and longer roasting time for pre-oxidation. Moreover, the pre-oxidation also makes the metallic Fe, which is produced by the subsequent reduction, have smaller grains and a more dispersed distribution.