Abstract: Vanadium and titanium are the important production and living materials. More than 90% vanadium and titanium resources deposit in titanomagnetite. China is rich in titanomagnetite ore. But due to the limitation of blast furnace operating condition in the modern blast furnace?converter industrial process, titanium element in titanomagnetite has not been extracted and utilized. The direct reduction?electric furnace smelting process, which is the new generation environmental technology of titanomagnetite resource comprehensive extraction and utilization, has received extensive attention. By dividing the reactions in blast furnace into reduction and smelting two steps, the direct reduction?electric furnace smelting process is very beneficial to the reaction condition control. With the same smelting reactor, the process can be classified as rotary kiln, rotary hearth furnace, shaft furnace and fluidized bed direct reduction according to the different reduction reactors. Taking the advantages of high heat and mass transfer efficiency and directly using ore powder, the fluidized bed exhibits the significant advantage in the industrial application of the direct reduction of titanomagnetite. In this work, the fluidized direct reduction process of titanomagnetite was expound and compared. By analyzing the difficult reduction characteristics of titanomagnetite ore, the reduction reinforcing method by pre-oxidation was emphatically introduced. The titania?ferrous oxides in titanomagnetite ore need much higher reduction potential than normal iron oxides, resulting in the low metallization degree and the high cost. The pre-oxidation can dissociate the titania?ferrous oxides to easily reducible free Fe2O3, improving the reaction efficiency and balance metallization degree. Concluding the main influence factors of defluidization, containing operating temperature, metallization degree, particle size, reducing atmosphere, particle shape and gangue content in the fluidized direct reduction process, five restrain methods for defluidization including inert additive, carbon coating, field force addition, granulation and bed structure improvement were summarized. Further, research and development directions were proposed for MgO inert additive, carbon coated and the bed structure improving methods.

Key words: fluidized-bed, fluidization, reduction, titanomagnetite, oxidation

摘要： 钒、钛是重要的生产生活资料，90%以上赋存于钒钛磁铁矿中. 我国钒钛磁铁矿资源储量丰富，但在当前高炉?转炉工业流程中，受高炉冶炼条件限制，钒钛磁铁精矿中的钛元素未能得到回收利用. 面对钒钛磁铁精矿铁钒钛资源全面提取利用难题和资源环保集约综合利用的迫切需求，直接还原?电炉熔分两步法流程受到广泛关注，其中流化床法因直接采用粉矿入炉、工序流程短、低温综合反应效率高，在直接还原工序中优势突出. 本工作阐述并对比了钒钛磁铁精矿流化床直接还原工艺，分析了钒钛磁铁精矿难还原的原因，重点介绍了流态化预氧化强化还原方法，同时归纳流化床直接还原过程中影响粘结失流的主要因素，总结了5种抑制铁矿粉粘结失流的直接方法，并提出了添加MgO惰性添加剂、碳包覆及改进床型结构的研究发展方向.

关键词: 流化床, 流态化, 还原, 钒钛磁铁矿, 氧化