Hydrogen-based shaft furnace process is gaining more and more attention due to its low carbon emission, and the reduction behavi-or of iron bearing burdens significantly affects its operation. In this work, the effects of reduction degree, temperature, and atmosphere on the swelling behavior of pellet has been studied thoroughly under typical hydrogen metallurgy conditions. The results show that the pellets swelled rapidly in the early reduction stage, then reached a maximum reduction swelling index (RSI) at approximately 40％ reduction degree. The crys-talline transformation of the iron oxides during the reduction process was the main reason of pellets swelling. The RSI increased significantly with increasing temperature in the range of 850–1050℃, the maximum RSI increased from 6.66％ to 25.0％ in the gas composition of 100％H2. With the temperature increased, the pellets suffered more thermal stress resulting in an increase of the volume. The maximum RSI de-creased from 19.78％ to 17.35％ with the volume proportion of H2 in the atmosphere increased from 55％ to 100％ at the temperature of 950℃. The metallic iron tended to precipitate in a lamellar structure rather than whiskers. Consequently, the inside of the pellets became regular, so the RSI decreased. Overall, controlling a reasonable temperature and increasing the H2 proportion is an effective way to decrease the RSI of pellets.

Zichuan Zhao;Jue Tang;Mansheng Chu;Xindong Wang;Aijun Zheng;Xiaoai Wang;Yang Li

School of Metallurgy,Northeastern University,Shenyang 110819,China;Institute for Frontier Technologies of Low-carbon Steelmaking,Northeastern University,Shenyang 110819,China;Liaoning Province Engineering Research Center for Technologies of Low-Carbon Steelmaking,Northeastern University,Shenyang 110819,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;HBIS Group Co.,Ltd,Shijiazhuang 050000,China;Xuanhua Iron and Steel Group Co.,Ltd,Shijiazhuang 075100,China;Iron and Steel Research Institute of HBIS Group Co.,Ltd,Shijiazhuang 050000,China

矿物冶金与材料学报

[1]Zichuan Zhao;Jue Tang;Mansheng Chu;Xindong Wang;Aijun Zheng;Xiaoai Wang;Yang Li-.Direct reduction swelling behavior of pellets in hydrogen-based shaft furnaces under typical atmospheres)[J].矿物冶金与材料学报,2022(10):1891-1900

behavi,swelled

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