预氧化强化印尼海砂矿还原分离及机理研究

以印尼某海砂矿为研究对象，采用光学显微镜、SEM-EDS、X射线衍射等分析测试手段，研究了预氧化对海砂矿原料特性及其固态还原分离行为的影响。结果表明，海砂矿结构致密、组元分布相对均匀; 预氧化破坏了其致密状态，形成疏松多孔结构，促进了钛磁铁矿和钛铁矿物相向钛赤铁矿和铁板钛矿的转变，同时使V、Ti局部预富集，有助于改善海砂矿还原分离性能。海砂矿经1 100 ℃预氧化90 min后，在C/Fe比0.6、还原温度1 350 ℃、还原时间60 min条件下还原，可获得金属化率93.87%的还原产物，还原产物经磨选分离可获得Fe品位90.90%、回收率93.47%的磁性产物以及TiO₂品位32.10%和回收率91.51%、V₂O₅品位2.04%和回收率91.04%的非磁性产物。

Mechanism for Reduction-Separation of Indonesia Iron Sand Intensified by Pre-oxidation Treatment

With a kind of typical Indonesia iron sand taken in the research, the effects of pre-oxidation treatment on the properties of iron-sand materials and their solid-state reduction and separation behavior were studied with optical microscope, SEM-EDS and X-ray diffraction. Results show that the iron sand has a dense structure, with relatively uniform distribution of compositions. Pre-oxidation destroys its dense structure and forms a loose porous structure, thus promoting the transformation of titanomagnetite and ilmenite mineral phases into ilmenite and brookite. In the meantime, the local pre-enrichment of V and Ti is conducive to the improvement of its reduction and separation performance. The iron sand is pre-oxidized at 1 100 ℃ for 90 min, and reduced with C/Fe ratio of 0.6, at 1 350 ℃ for 60 min, leading to a reduced product with a metallization rate of 93.87%. After further grinding and separation processes, a magnetic product grading 90.90% Fe can be finally reclaimed at 93.47% recovery, and a non-magnetic product is obtained grading 32.10% TiO₂ and 2.04% V₂O₅, with recoveries of 91.51% and 91.04%, respectively.