铁矿氧化球团气基直接低温还原粉化行为研究

铁矿氧化球团在还原过程中的破裂、粉化会严重影响生产的正常进行。研究了还原温度和还原气氛对氧化球团直接低温还原粉化性能及还原后球团抗压强度的影响，并以还原后球团内部的Leica DMRXP显微图片为依据，分析了球团的粉化行为。结果表明：气基直接还原温度从450 ℃提高到550 ℃，RDI+6.3和RDI+3.15下降、RDI-0.5上升，当还原温度进一步提高到600 ℃时，RDI+6.3和RDI+3.15开始回升、RDI-0.5开始降低；H2与H2+CO的体积比升高，RDI+6.3和RDI+3.15上升、RDI-0.5显著下降；温度及气氛对还原球团抗压强度的影响规律与对低温还原粉化率的影响规律相反，即还原粉化率降低时抗压强度升高，还原粉化率升高时抗压强度降低。

Research of the Behavior of Iron Ore Pellet on Low Temperature Reduction Degradation in Gas-based Direct Reduction Process

Cracking and degradation in the reduction process of iron ore oxidized pellets has serious influence on production. The effect of reduction temperature and reducing atmosphere on reduction degradation performance of oxidized pellet and the compressive strength of reduced pellet was investigated. And the reduction degradation is analyzed based on the inner microstructure pictures of the reduced pellets by Leica DMRXP microscope. The results indicate that RDI+6.3 and RDI+3.15 decreased while RDI-0.5 increased as the reduction temperature increases from 450 ℃ to 550 ℃ in gas-based direct reduction process. When the reduction temperature raises to 600 ℃，RDI+6.3 and RDI+3.15 begins to increase while RDI-0.5 decrease. When the volume ratio of H2/(H2+CO) increases，RDI+6.3 and RDI+3.15 increased，while RDI-0.5 decreased dramatically. The temperature and reducing atmosphere have an inverse effect on compressive strength of reduced pellets and the low temperature reduction degradation rate of oxidized pellet. Namely，the compressive strength of reduced pellets increased when reduction degradation rate of oxidized pellet decreased，and the compressive strength of reduced pellets decreased when reduction degradation rate increased.