Influence of H₂–H₂O Content on the Reduction of Acid Iron Ore Pellets in a CO–CO₂–N₂ Reducing Atmosphere

Abstract

Using hydrogen as a reducing agent for iron production has been the focus of several studies due to its environmental potential. The aim of this work is to study the influence of H 2-H 2 O content in the gas phase on the reduction of acid iron ore pellets under simulated blast furnace conditions. Temperature and gas compositions for the experiments were determined with multi-point vertical probes in an industrial blast furnace. The results of the reduction tests show that higher temperatures and H 2 content increase the rate and extent of reduction. For all the gas and temperature combinations, morphological, mineralogical, and microstructure changes were observed using different characterization techniques. Microscopy images reveal that H 2-H 2 O, in the gas phase, has a positive influence on reduction, with metallic iron forming at the pellet's periphery and core at lower temperatures compared to CO-CO 2-N 2 reducing gas. Porosity and surface area changes were determined using a gas pycnometer and the BET method. The results indicate that increasing the reduction temperatures and H 2 content results in greater porosity and a larger surface area. Moreover, carbon deposition did not take place, even at lower temperatures. A rate minimum was detected for pellets reduced at 800°C, probably due to metallic iron formation, hindering the diffusion of reducing gases through the product iron layer.

A Review on the Kinetics of Iron Ore Reduction by Hydrogen

“…This indicates the importance of choosing the right ratio of H 2 /CO and not simply raising the amount of hydrogen content [33]. Abdelrahim et al, found that the pellets reduced in CO-CO 2 -H 2 -H 2 O-N 2 have more porosity and surface area than that reduced in CO-CO 2 -N 2 [34]. Formation of carbide, slower reduction, and reaching the complete reduction at higher temperatures, for the hematite reduction by CO in comparison with H 2 was reported by Abu Tahari et al [35].…”

Coke Gasification in Blast Furnace Shaft Conditions with H2 and H2O Containing Atmospheres

“…Elevated amounts of hydrogen also affect the reduction of the iron bearing layers in the furnace. [ 25 ] Thus, further research on the topic of hydrogen and water vapor in BF is important.…”

Development of Cold-Bonded Briquettes Using By-Product-Based Ettringite Binder from Ladle Slag

“…To assess the behavior of the produced briquettes under high-temperature resembling conditions in a BF, a modified blast furnace simulator (BFS) was used. The schematic diagram of the BFS, which was used in our previous work to study pellet reduction [44], is shown in Fig. 1.…”