利用热重分析的方法研究了Fe2O3在竖式电阻炉内被CO/CO2混合气体还原，Na2O对其还原行为的影响，共设计了4个成分，分别为纯Fe2O3、Fe2O3-1％Na2O、Fe2O3-3％Na2O和Fe2O3-5％Na2O。在还原过程中由于还原失氧引起的试验小饼失重量被实时记录下来，根据这些数据可以计算出还原反应速率以及化学反应的速率常数，以此来判断Na2O对Fe2O3还原性的影响。同时利用扫描电镜观察了还原后试样的微观形貌变化。研究发现：Na2O的存在将阻碍Fe2O3的还原。通过对还原后小饼的显微形貌观察，结合FeO-Na2O二元相图，发现这种负面影响主要是由于在还原过程中产生液相引起的。另外，还检测了还原前后试验小饼的孔隙率和体积变化。检测结果确认：还原后含Na2O的试验小饼的孔隙率和体积都有所下降。分析认为这种现象同样归因于还原过程中液相的产生。
Abstract
Fe2O3 and Fe2O3 doped with Na2O from 1.0 to 5.0 mass percent compacts were isothermally reduced at various temperatures from 1073 to 1273K with CO/CO2 mixed gas in a vertical resistance furnace. To determine the effect of Na2O on the reduction of Fe2O3 compacts, mass loss due to oxygen removal was continuously recorded from which the reduction rate and rate constant was obtained. The morphology change was also observed by SEM. The results show that Na2O retards the reduction of Fe2O3 compacts. Morphological examination of reduced compacts and the binary phase diagram of FeO-Na2O show liquid phase formation during the reduction, which decreases the rate of reduction. Porosity and volumetric expansion of reduced compacts were investigated, which shows that the volume and porosity of reduced Fe2O3-Na2O compacts are both decreased with higher Na2O content due to the existence of liquid phase.
关键词
Na2O /
Fe2O3 /
还原速率 /
显微形貌 /
液相
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1]赵宏博，程树森，白永强，等.高炉块状带矿石逐渐升温还原对料层透气性影响[J].钢铁,2011,46(11):10-
[2]张俊，李春增，朱利，等.添加MgO对烧结产物还原性能的影响[J].钢铁,2009,44(10):6-
[3]R. Jaffarullah,AArumugam,V. K. Jha,et al.Reduction and Degradation Behavior of Sinter under Simulated Vertical Probe Trial Condition.[J].Iron Steel Inst. Jpn. Int,2008,48(7):918-
[4]K. Yamaguchi,KHiguchi,Y. Hosotani,et al.Influence of Micro Pore on Reducibility and Permeability of Sinter above 1000℃ in Blast Furnace. [J].Tetsu-to-Hagan,1998,84(10):702-
[5]A. A. El-Geassy.Gaseous Reduction of Mgo-doped Fe2O3 Compacts with Carbon-monoxide at 1173-1473K.[J].Iron Steel Inst. Jpn. Int,1996,36(11):1328-
[6]A. A. El-Geassy.Reduction of CaO and/or MgO-doped Fe2O3 Compacts with Carbon-monoxide at 1173-1473K.[J].Iron Steel Inst. Jpn. Int,1996,36(11):1344-
[7]A. A. El-Geassy.Stepwise Reduction of CaO and/or MgO Doped-Fe2O3 Compacts to Magnetite then Subsequently to Iron at 1173-1473K.[J].Iron Steel Inst. Jpn. Int,1997,37(9):844-
[8]A. A. El-Geassy.Influence of doping with CaO and/or MgO on stepwise reduction of pure hematite compacts. [J].Ironmaking and Steelmaking,1999,26(1):41-
[9]N. Shigematsu and HIwai.Effect of CaO Added with SiO2 and/or Al2O3 on Reduction Rate of Dense Wustite by Hydrogen[J].Iron Steel Inst. Jpn. Int,1989,29(6):486-
[10]HP. Pimenta and VSeshadri.Characterisation of Structure of Iron Ore Sinter and its Behavior during Reduction at Low Temperatures[J].Ironmaking and steelmaking,2002,29(3):169-
[11]T. Inami and KSuzuki.Effects of SiO2 and Al2O3 on the Lattice Parameter and CO Gas Reduction of CaO-containing Dense Wustite[J].Iron Steel Inst. Jpn. Int,2003,43(3):314-
[12]K. Yamaguchi,HUeno,T. Kawaguchi,et al.Influence of Al2O3 on Reduction-Meltdown Behavior of Sinter in Blast Furnace[J].Iron Steel Inst. Jpn. Int,1994,34(12):964-
[13]E. T. Turkdogn .Physical chemistry of high temperature technology[M][J].Academic Press, New York,1980,:11-
[14]A. A. El-Geassy,M. I. Nasr and M. M. Hessien.Effect of reducing gas on the 36 chaning during reduction of iron oxide compacts,36,640.[J].Iron Steel Inst. Jpn. Int,1996,36(6):640-
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
