Reduction of Iron‐Ore Pellets Using Different Gas Mixtures and Temperatures

Korobeinikov, Yuri; Meshram, Amogh; Harris, Christopher; Kovtun, Oleksandr; Govro, Joe; O’Malley, Ronald J.; Volkova, Olena; Sridhar, Seetharaman

doi:10.1002/srin.202300066

Cited by 13 publications

(4 citation statements)

References 38 publications

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“…[ 14 ] However, the microstructure varies depending on the reduction temperature. Similar findings have been reported by Korobeinikov et al, [ 33 ] Turkdogan et al [ 7 ] and He et al [ 34 ] Regardless of the reduction temperature, two distinctly different zones were present inside the partially reduced samples, the different zones are shown in Figure 7. The microstructure in Zone 1 mainly consisted of iron and included some grains with an unreduced core.…”

Section: Discussionsupporting

confidence: 90%

“…The activation energy calculated by the Arrhenius equation can be used to identify the rate limiting step of the reduction mechanism. [33,37] As the rate limiting step may differ with the reduction degree, activation energy was calculated in the interval R = 0.1-0.5. The calculation was made from 0.1°of reduction to exclude the heating of the sample, which may distort the activation energy estimation.…”

Section: Discussionmentioning

confidence: 99%

“…This value is in line with previously reported values. [33,34,37] It is important to note that, as there is a mixed control regime, only the apparent activation energies can be calculated from the experimental reduction curves. Therefore, the results should be treated with care.…”

Section: Discussionmentioning

confidence: 99%

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The Influence of Nitrogen on Hydrogen Reduction of Iron Ore Pellets

Fogelström,

Martinsson,

Kojola

2024

steel research int.

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As the iron and steel industry now strives for a carbon neutral industry, hydrogen‐based direct reduction shaft furnace technology has become an alternative to the heavily fossil‐depending blast furnace route. Research questions related to the future full‐scale production have, therefore, become more interesting. Depending on the operational conditions, the H2 concentration and temperature will vary across the length of the reactor. This work studies the effect of nitrogen in a hydrogen‐reducing gas during the reduction of commercial iron ore pellets using thermogravimetric analysis. The reducing gas consisted of either pure hydrogen or a mixture of 90–70 vol% hydrogen and 10–30 vol% nitrogen at 773, 873, 973, 1073, and 1173 K. It is found that the reduction rate decreased with decreasing temperature and increasing nitrogen content. The effect of nitrogen on the reduction rate is more profound than expected from the decreased hydrogen partial pressure alone. To aid the discussion, partially reduced pellets are studied using optical and scanning electron microscopy. It is found that the microstructure is strongly dependent on the temperature but independent of the nitrogen content.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

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The Influence of Nitrogen on Hydrogen Reduction of Iron Ore Pellets

Fogelström,

Martinsson,

Kojola

2024

steel research int.

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“…An increase in the porosity of the pellets also occurs in the reduction process itself [97]. The total porosity increases at higher temperatures, while the porosity inside the reduced iron decreases and the porosity between the particles increases [58,98].…”

Section: Results Of Research Studies Focused On the Reduction In Iron...mentioning

confidence: 99%

An Overview Analysis of Current Research Status in Iron Oxides Reduction by Hydrogen

Miškovičová,

Legemza,

Demeter

et al. 2024

Metals

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This paper focuses on the study of current knowledge regarding the use of hydrogen as a reducing agent in the metallurgical processes of iron and steel production. This focus is driven by the need to introduce environmentally suitable energy sources and reducing agents in this sector. This theoretical study primarily examines laboratory research on the reduction of Fe-based, metal-bearing materials. The article presents a critical analysis of the reduction in iron oxides using hydrogen, highlighting the advantages and disadvantages of this method. Most experimental facilities worldwide employ their unique original methodologies, with techniques based on Thermogravimetric analysis (TGA) devices, fluidized beds, and reduction retorts being the most common. The analysis indicates that the mineralogical composition of the Fe ores used plays a crucial role in hydrogen reduction. Temperatures during hydrogen reduction typically range from 500 to 900 °C. The reaction rate and degree of reduction increase with higher temperatures, with the transformation of wüstite to iron being the slowest step. Furthermore, the analysis demonstrates that reduction of iron ore with hydrogen occurs more intensively and quickly than with carbon monoxide (CO) or a hydrogen/carbon monoxide (H2/CO) mixture in the temperature range of 500 °C to 900 °C. The study establishes that hydrogen is a superior reducing agent for iron oxides, offering rapid reduction kinetics and a higher degree of reduction compared to traditional carbon-based methods across a broad temperature range. These findings underscore hydrogen’s potential to significantly reduce greenhouse gas emissions in the steel production industry, supporting a shift towards more sustainable manufacturing practices. However, the implementation of hydrogen as a primary reducing agent in industrial settings is constrained by current technological limitations and the need for substantial infrastructural developments to support large-scale hydrogen production and utilization.

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A Simplified Approach Based on Cellular Automata for Describing Direct Reduced Iron Production in Different Reducing Conditions

Mapelli,

Dall’Osto,

Mombelli

et al. 2023

steel research int.

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A quick computation approach based on cellular automata is developed and implemented to describe the reduction of iron ore pellets by a mixture of reducing agents featured by different H2/CO ratios. The evolution of oxygen concentration inside the pellet is followed from the beginning to the end of contact between reducing agent and pellet. The variation of thermal state of pellets and gas mixture is computed based on their initial temperature, considering the heat involved and the convective heat exchange between pellet and gas mixture. The use of cellular automata and finite‐difference method to solve the diffusion equation point out the absence of any diffusion coefficient value, allowing to make the model fit the experimental trial, because the problem is that it is not ruled just by diffusion but also by the concentration variation of reducing agent inside the pellet due to porosity increasing during reduction. The updating of the reducing agents concentration implies a sharp decrease of oxygen concentration that the cellular automata model considers. The developed model is able to provide the in‐line control of reduction process and could be used to adjust the chemical concentration and temperature of injected reducing agents.

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Reduction of Iron‐Ore Pellets Using Different Gas Mixtures and Temperatures

Cited by 13 publications

References 38 publications

The Influence of Nitrogen on Hydrogen Reduction of Iron Ore Pellets

The Influence of Nitrogen on Hydrogen Reduction of Iron Ore Pellets

An Overview Analysis of Current Research Status in Iron Oxides Reduction by Hydrogen

A Simplified Approach Based on Cellular Automata for Describing Direct Reduced Iron Production in Different Reducing Conditions

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