Effect of Mixed Charging of Nut Coke and Sinter on Hydrogen-Rich Smelting Process of Blast Furnace

• Published in: Journal of sustainable metallurgy Vol. 9; no. 1; pp. 280 - 293
• Main Authors: Chen, Yanbiao, Yu, Yuanhao, Gao, Yan, Wang, Jingsong, Xue, Qingguo, Zuo, Haibin
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2023; Springer Nature B.V
• Subjects: Air flow; Blast furnace gas; Blast furnace iron mixers; Blast furnace practice; Carbon; Carbon content; Carburizing; Charging; Coke fired furnaces; Earth and Environmental Science; Environment; Gas mixtures; Hydrogen; Ironmaking; Melting; Metallic Materials; Metallurgy; Reducing agents; Research Article; Sinter; Slag; Smelting; Softening; Sustainable Development; Softening-melting properties; Nut coke; Reduction; Hydrogen-rich blast furnace
• ISSN: 2199-3823; 2199-3831
• DOI: 10.1007/s40831-022-00645-2

With the increasing demand for low-carbon metallurgy, large-scale hydrogen-rich smelting has become an effective way to realize low-carbon ironmaking. The injection of hydrogen-rich fuel into blast furnace changed the reduced atmosphere, affecting the reaction behavior and structure of the burden. Production practice has proved that the use of nut coke is an important measure for alleviating the increasingly tense relationship between coke supply and realizing low reducing agent ironmaking. In this paper, the effect of mixed charging of nut coke and sinter on reduction and softening-melting properties in the hydrogen-rich smelting process of blast furnace is studied. The results showed that the close contact between nut coke and sinter promoted carbon dissolution and water–gas reaction to generate more CO and H 2 , thus increasing the reduction potential in the gas mixture. With the increase of nut coke and hydrogen-rich ratio, the softening–melting properties of the burden were improved. This change narrowed and lowered down the position of cohesive zone, triggering to an enlargement of indirect reduction zone, which was conducive to strengthening blast-furnace smelting and saving coke. The permeability resistance of the burden bed was reduced, which was beneficial to the good airflow distribution and the gas utilization rate. There was a slag layer between nut coke and metal iron phase in the softening–melting process, and the slag could quickly fuse with the ash distributed on the nut coke surface to dissolve it, thus promoting the occurrence of carburizing reaction and improving the dripping behavior of the burden. Graphical Abstract