Abstract：High-proportion pellet smelting is the development trend of blast furnace ironmaking. Due to the differences in chemical composition, mineral composition and structure, the reasons for the reduction and swelling of pellets produced or used by different enterprises are different and relatively complex. Facing the major national strategic needs of ensuring the safe supply of mineral resources. Pellets prepared from Bayan Obo iron ore concentrate were selected as the research object. According to the iron oxide reduction theory of pellets, the influence mechanism of basicity on the reduction swelling performance of pellets was studied from the perspective of thermodynamics. The XRD results were combined to investigate the change law of calcium-binding phase in pellet production and the influence on the reduction swelling of pellet. A reasonable basicity that meets the requirement of reducing swelling rate of flux pellets in blast furnace ironmaking was found. Increase the proportion of Bayan Obo iron concentrate pellets in iron and steel smelting production. Improve the reduction and swelling theory of special ore pellets to provide theoretical support for the efficient smelting of complex intergrowth ores. The results show that with the increase of basicity, the swelling rate of pellets first increased and then decreased. When the basicity was 0.8, the swelling rate was the largest, reaching 75.743%. Its shape was like an open petal, and it could not maintain its original spherical shape. The optimum basicity of the pellets prepared is 1.4 by synthesizing the iron grades of pellets with different basicity and the reduction swelling rate. With the increase of basicity, the amount of liquid phase generated of pellets first decreasing and then increasing. The amount of liquid phase generated at an basicity of 0.8 was the least. The reason for the increase in the swelling rate of the pellets is that the crystallinity of the pellets increases, the grains are coarse, and the crystal structure gradually tends to be ordered, which lays the foundation for the growth of iron whiskers; The reason for the decrease in swelling rate is because of the generation of calcium ferrite. Calcium ferrite has excellent binder phase properties and good reducibility,which improves the strength of the pellets,enhances the ability to resist swelling stress, and promotes the uniform swelling of the pellets. The volume swelling caused by the crystal transformation of Fe2O3→Fe3O4 is reduced.
柴轶凡, 樊莹杰, 高兴, 罗果萍, 王艺慈, 安胜利. 碱度对白云鄂博矿球团矿还原膨胀性能的影响[J]. 钢铁, 2023, 58(1): 13-21.
CHAI Yi-fan, FAN Ying-jie, GAO Xing, LUO Guo-ping, WANG Yi-ci, AN Sheng-li. Influence of basicity on reduction swelling properties of pellets prepared from Bayan Obo iron ore[J]. Iron and Steel, 2023, 58(1): 13-21.
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2023, Vol. 58 
