Influence of addition amount and charging method of iron coke on softening-melting-dropping properties of blast furnace mixed burdens
In the context of"carbon peaking and carbon neutrality",blast furnace(BF)ironmaking is an important link in achieving the"carbon peaking and carbon neutrality"goal in the steel industry.Iron coke is a new material that can achieve low-carbon smelting in BF.The impact of iron coke on the softening-melting-dropping performance of the BF mixed burdens is crucial for the application of iron coke in low-carbon BF smelting.The softening-melting-dropping properties evolution of BF mixed burdens under different iron coke addition amounts and charging methods have been systematically studied.Furthermore,the rapid cooling experiment has been conducted to explore and ana-lyze the reduction,softening-melting,slag-iron dripping and material layer structure evolution behavior of BF mixed burdens at different smelting stages,and the influence mechanism of iron coke on the softening-melting-dropping performance of BF mixed burdens has been revealed.The results indicate that the addition of iron coke among iron-bearing burdens has a significant improvement effect on the softening-melting-dropping properties of BF mixed bur-dens.20％-30％is the appropriate addition amount of iron coke used for BF smelting,and mixed charging is the appropriate charging method for iron coke.Compared with the situation that without adding iron coke,the softening interval of mixed burdens under the above optimization condition is increased from 136 ℃ to 197 ℃,the melting tem-perature interval is decreased from 171 ℃ to 152 ℃,the position of cohesive zone is relatively low;the dripping rate of slag and iron is improved from 59.1％to 78.7％;the maximum pressure drop of burden bed is decreased from 39.5 kPa to 3.6 kPa,and the S value is reduced from 3 616.1 kPa·℃ to 276.6 kPa·℃.Through analysis and dis-cussion,the mechanism of adding iron coke to improve the softening-melting-dropping properties of BF mixed bur-dens is obtained.The increase in the addition amount of iron coke and the adoption of a mixed charging method between iron coke and iron-bearing burdens both can increase the dispersion distribution of iron coke among iron-bearing burdens and strengthen the close contact between iron coke and iron-bearing burdens.The above effects will strengthen the reduction promotion effect of iron coke on iron-bearing burdens,adjust and optimize the slag composi-tion to reduce the viscosity of slag,promote metallic iron carburization,and support and interval the iron-bearing bur-dens.This can significantly improve the softening-melting-dropping properties of BF mixed burdens.
iron cokeaddition amountcharging methodblast furnacemixed burdenssoftening-melting-dropping properties
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