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在600～750℃的温度范围、空气气氛下焙烧攀枝花钛铁矿,通过观察分析钛铁矿氧化后的微观形貌、物相组成以及氧化动力学,对钛铁矿的氧化机理进行了详细地研究。试验结果表明钛铁矿的氧化机制是一种Fe、O离子相互竞争扩散的反应机制。在反应初期,钛铁矿的氧化是通过Fe离子的向外扩散完成,氧化产物是Fe2O3和Fe2Ti3O9,其中Fe2O3会在颗粒表面富集;当反应进行到一定程度后(表面Fe2O3层厚度达到1～2μm),O离子的向内扩散在反应中占主导,颗粒内部逐渐形成Fe2O3和TiO2。由于从Fe离子扩散转变到O离子扩散均发生在表面氧化铁层厚度达到1～2μm时,这一转变时间与温度和钛铁矿颗粒粒径无关,所以Fe离子扩散在整个氧化过程中所占的比重会随着钛铁矿颗粒粒径的减小而增大,而O离子扩散则相反。
In the temperature range of 600 ~ 750 ℃, the Panzhihua ilmenite was roasted under the air atmosphere. The microstructure, phase composition and oxidation kinetics of ilmenite after oxidation were observed and analyzed. The oxidation mechanism of ilmenite was detailed the study. The experimental results show that the oxidation mechanism of ilmenite is a reaction mechanism in which Fe and O ions compete with each other for diffusion. In the early stage of the reaction, ilmenite is oxidized by outward diffusion of Fe ions, and the oxidation products are Fe2O3 and Fe2Ti3O9, in which Fe2O3 is enriched on the particle surface. When the reaction proceeds to a certain extent (the surface Fe2O3 layer thickness reaches 1 ~ 2μm). The inward diffusion of O ions dominates the reaction and Fe2O3 and TiO2 are gradually formed inside the particles. Since the transition from Fe ions to O ions occurs when the thickness of the surface iron oxide layer reaches 1 to 2 μm, the conversion time is independent of the temperature and the particle size of the ilmenite particles, the diffusion of Fe ions in the entire oxidation process accounts for Of the proportion will increase with the ilmenite particle size decreases, while the O ion diffusion is the opposite.