预氧化钛铁矿弱还原动力学研究

Study on the weak reduction kinetics of preoxidized ilmenite

以钛铁矿为原料制备人造金红石是氯化法钛白生产的重要环节,探求合适的钛铁矿焙烧预处理方法以改善钛铁矿的物相组成和还原过程。这里对钛铁矿的预氧化、还原焙烧过程物相规律影响机理进行了系统研究。其结果如下:对两种典型的热力学稳定(氧化温度:T<800℃和T≥800℃)预氧化矿在600~800℃温度范围内弱还原焙烧过程的研究结果表明预氧化矿的弱还原焙烧有两种相互竞争的反应路径。当还原温度高时(如750℃和800℃),预氧化生成的金红石参与还原反应而被消耗。在T<800℃和T≥800℃下分别预氧化的钛铁矿都被还原成钛铁矿。当还原温度较低时(如600℃),金红石不参与反应。在T<800℃预氧化钛铁矿的赤铁矿被还原为金属Fe和金红石;而在T≥800℃预氧化钛铁矿的假板铁矿被还原为钛铁矿。

The preparation of man-made rutile from ilmenite is an important part of the production of titanium dioxide by chlorination,and the appropriate ilmenite roasting pretreatment method is proposed to improve the phase composition and reduction process of ilmenite. The influence mechanism of the pre-oxidation and reduction roasting process of ilmenite is studied systematically. The results are as follows： The results of two weak thermodynamically stable（ oxidation temperature： T 800℃ and T≥800℃） preoxidized ore in the temperature range of 600 ~ 800℃ show that the weak oxidation of the preoxidized ilmenite has two competing reaction paths. When the reduction temperature is high（ such as 750 and 800℃）,the TiO_2 produced by the preoxidation is consumed in the reduction reaction. In the T 800℃ and T ≥ 800℃,respectively,pre-oxidation of ilmenite are reduced to Fe TiO_3. When the reduction temperature is low（ such as 600℃）,Ti O2 does not participate in the reaction. At the T 800℃ preoxidized ilmenite Fe_2O_3 is reduced to metal Fe and TiO_2; and in the T≥ 800℃ preoxidation of ilmenite Fe_2TiO_5 is reduced to Fe TiO_3.