Evaluation of Reduction Behavior of the Acid Pellets Prepared with Sinter-Grade Iron Ore Fines by 55% H₂-35% CO-10% N₂ and 100% H₂

초록

Hydrogen is receiving much attention as a reducing agent in iron and steel production processes. Hydrogen-based DRI (Direct-Reduced Iron) production in a shaft furnace is currently under development in many countries. However, due to the limited resources for DR-grade pellets, the hydrogen reduction technology of the pellets produced with sinter-grade iron ore fines is highly anticipated. In this study, the reduction characteristics of the acid pellets produced with sinter-grade iron ore fines were investigated by a typical reformed natural gas (55% H2-35% CO-10% N2), and 100% H2 at temperatures ranging from 973 to 1173 K. The lab-made acid pellet exhibited an average cold crushing strength of 335 kg. When the pellets were reduced by 55% H2-35% CO-10% N2, the degree of metallization was satisfied only at 1173 K. On the other hand, when the pellets were reduced by 100% H2, the degree of metallization was acceptable: 93.04 and 95.54% at 1073 and 1173 K, respectively. The reduction time by 100% H2 at 1073 K was 29 min, whereas that by 55% H2-35% CO-10% N2 at 1173 K was 57 min. Accordingly, the hydrogen reduction process can reduce the reduction time by 51%, although the reduction temperature by 100% H2 is 100 K lower than that by 55% H2-35% CO-10% N2.

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