中文摘要：

研究了钒钛磁铁精矿在等温预氧化条件下的物相组成及其转变情况,并将钒钛磁铁精矿原矿和预氧化后的样品以煤粉为还原剂进行直接还原,利用XRD和ICP-AES对产物进行物相和成份分析.研究结果表明：预氧化能够加速还原过程,提高金属化率,较为适宜的预氧化条件为：预氧化温度为900℃,预氧化时间为30 min;预氧化矿在1 200℃下还原60 min,比钒钛磁铁精矿原矿金属化率提高了14.0%.其强化还原的机理是：在预氧化过程中Fe3O4被氧化成Fe2O3,FeTiO3被氧化成Fe2O3.FeTiO3固溶体、Fe2O3和TiO2,破坏了钒钛磁铁精矿的结构,矿粉内部形成了大量孔隙,改善了还原反应的动力学条件,加速了还原过程.

英文摘要：

The isothermal preoxidation of vanadium-bearing titanomagnetite concentrates was performed in present investigation.The corresponding phase composition and transformation of the preoxidized samples were investigated.With the pulverized coal as a reductant,the vanadium-bearing titanomagnetite concentrates and preoxidized samples were reduced.XRD and ICP-AES techniques were employed to identify the main phases and chemical composition of the samples.The results showed that preoxidation accelerate the reduction of vanadium-bearing titanomagnetite concentrates and improve the metallization degree of the preoxidized samples.Preoxidation at 900 ℃ for 30 min was the suitable preoxidation condition.The metallization degree of preoxidized sample increased 14.0% at 1 200 °C for 60 min than metallization degree of vanadium-bearing titanomagnetite concentrates in reduction process.The enhanced reduction mechanism was that the magnetite was preoxidised to haematite,and ilmenite was preoxidised to haematite-ilmenite solid solution,haematite and TiO2 in the preoxidation process,which the structure was destroyed that of raw vanadium-bearing titanomagnetite concentrates and formed plenty of pores in the granule.The preoxidation improve the reduction dynamics,and accelerate the reduction process.