钒钛磁铁精矿固态还原的强化研究

Study of Solid State Reduction Strengthening of Vanadium-Titanium Magnetite Concentrate

以攀枝花钒钛磁铁精矿为对象,系统研究了钒钛磁铁精矿固态还原行为及预氧化对其还原过程的强化行为,考察了预氧化温度以及预氧化时间对球团金属化率、物相变化和显微结构的影响.研究结果表明,与未氧化的还原球团相比,在900℃下氧化6min后的还原球团金属化率提高了12.86%;延长预氧化时间可以有效提高还原球团的金属化率,900℃下预氧化15min后的还原球团金属化率较氧化6min后的还原球团提高了8.08%.经过预氧化处理后,钒钛磁铁精矿的物相变化表明球团中磁铁矿氧化形成赤铁矿,且钛铁矿被氧化为TiO2和赤铁矿,随后铁板钛矿形成.钒钛磁铁精矿球团的显微结构变化表明,预氧化处理后的球团颗粒具有较多的内部空隙以及不规则的颗粒边界,从而使还原煤与铁矿颗粒的接触增强,还原性能得到改善.

Panzhihua vanadium-titanium magnetite concentrate was used to study the solid state reduction behavior and strengthening technology of reduction process by pre-oxidation treatment.The influences of pre-oxidation temperature and time on the metallization rate,phase variation and microstructure were investigated.The results show the metallization rate after oxidizing for 6 min at 900 ℃ was 12.86%higher than that without pre-oxidation.A long pre-oxidation time can effectively improve the metallization rate of the pellets,and the metallization rate after pre-oxidizing for 15 min at 900 ℃ was 8.08%higher than the result of 6 min.After the pre-oxidation,the hematite appears due to the oxidation of magnetite,the hematite and TiO_2 appear from the oxidization of ilmenite,and lastly the pseudobrookite forms.The particles of pre-oxidized vanadium-titanium magnetite concentrate contain many inner defects and an irregular shape,which promotes the reaction of the reductant and vanadium-titanium magnetite concentrate particles and further enhances the reducing property significantly.