Hierarchical nature of hydrogen-based direct reduction of iron oxides

Ma, Yan; Filho, Isnaldi Rodrigues de Souza; Bai, Yang; Schenk, Johannes; Patisson, Fabrice; Beck, Arik; Bokhoven, Jeroen A. van; Willinger, Marc Georg; Li, Kejiang; Xie, Degang; Ponge, Dirk; Zaefferer, Stefan; Gault, Baptiste; Mianroodi, Jaber Rezaei; Raabe, Dierk

doi:10.1016/j.scriptamat.2022.114571

Cited by 49 publications

(23 citation statements)

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“…Gradient effects (across pellet and reactor dimensions) and a few examples of the multiple scales involved regarding reactor concepts in the sustainable metallurgy of steels, here shown exemplarily for the case of hydrogen-based direct reduction in a static bed shaft reactor. , Most of these challenges are similar to those observed in other reactor concepts and other processes in sustainable reduction. ,, The figure is reproduced with permission from ref . Copyright 2022, Springer, Creative Commons Attribution 4.0 International License.…”

Section: Element- and Alloy-specific Direct Sustainability Topicsmentioning

confidence: 83%

“…This chapter does not provide an exhaustive overview of transport, nucleation, and growth kinetics in metallic materials, as this is covered by standard textbooks, but it highlights some important kinetics aspects that are of particular relevance for the direct sustainability of metallurgy. In this context, different research topics in the field of kinetics can be distinguished, Figure Macroscopic consideration of mass transport, percolation, temperature, and chemical reaction kinetics.…”

Section: Some Thermodynamic and Kinetic Foundations Of Direct Sustain...mentioning

confidence: 99%

“…This figure shows an example of the multiple scales in the context of kinetic and thermodynamic simulations (above the images) and experiments (below the images) for the example of the solid-state direct reduction of iron oxides by using hydrogen . The figure is reproduced from ref with permission. Copyright 2022, Elsevier.…”

Section: Some Thermodynamic and Kinetic Foundations Of Direct Sustain...mentioning

confidence: 99%

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The Materials Science behind Sustainable Metals and Alloys

Raabe

2023

Chem. Rev.

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Production of metals stands for 40% of all industrial greenhouse gas emissions, 10% of the global energy consumption, 3.2 billion tonnes of minerals mined, and several billion tonnes of by-products every year. Therefore, metals must become more sustainable. A circular economy model does not work, because market demand exceeds the available scrap currently by about two-thirds. Even under optimal conditions, at least one-third of the metals will also in the future come from primary production, creating huge emissions. Although the influence of metals on global warming has been discussed with respect to mitigation strategies and socio-economic factors, the fundamental materials science to make the metallurgical sector more sustainable has been less addressed. This may be attributed to the fact that the field of sustainable metals describes a global challenge, but not yet a homogeneous research field. However, the sheer magnitude of this challenge and its huge environmental effects, caused by more than 2 billion tonnes of metals produced every year, make its sustainability an essential research topic not only from a technological point of view but also from a basic materials research perspective. Therefore, this paper aims to identify and discuss the most pressing scientific bottleneck questions and key mechanisms, considering metal synthesis from primary (minerals), secondary (scrap), and tertiary (re-mined) sources as well as the energy-intensive downstream processing. Focus is placed on materials science aspects, particularly on those that help reduce CO2 emissions, and less on process engineering or economy. The paper does not describe the devastating influence of metal-related greenhouse gas emissions on climate, but scientific approaches how to solve this problem, through research that can render metallurgy fossil-free. The content is considering only direct measures to metallurgical sustainability (production) and not indirect measures that materials leverage through their properties (strength, weight, longevity, functionality).

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Section: Element- and Alloy-specific Direct Sustainability Topicsmentioning

confidence: 83%

Section: Some Thermodynamic and Kinetic Foundations Of Direct Sustain...mentioning

confidence: 99%

Section: Some Thermodynamic and Kinetic Foundations Of Direct Sustain...mentioning

confidence: 99%

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The Materials Science behind Sustainable Metals and Alloys

Raabe

2023

Chem. Rev.

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“…1). An alternative approach for large-scale and sustainable iron oxide reduction is the use of hydrogen gas, its carriers [9], and their plasma variants [10], provided that reducing agents (instead of carbon) originate from sustainable or low-carbon sources [11]. In particular, the current study addressed hydrogenbased direct reduction (HyDR) with molecular hydrogen.…”

Section: Introductionmentioning

confidence: 99%

“…The HyDR involves multiple phase transformations [11][12]. At temperatures above 570°C, HyDR proceeds along the sequence Fe 2 O 3 (hematite) → Fe 3 O 4 (magnetite) → Fe (1−x) O (wüstite) → α-Fe (BCC iron) or γ-Fe (FCC iron).…”

Section: Introductionmentioning

confidence: 99%

Hydrogen-based direct reduction of iron oxide at 700°C: Heterogeneity at pellet and microstructure scales

Filho

Zhang

et al. 2022

Int J Miner Metall Mater

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Steel production causes a third of all industrial CO2 emissions due to the use of carbon-based substances as reductants for iron ores, making it a key driver of global warming. Therefore, research efforts aim to replace these reductants with sustainably produced hydrogen. Hydrogen-based direct reduction (HyDR) is an attractive processing technology, given that direct reduction (DR) furnaces are routinely operated in the steel industry but with CH4 or CO as reductants. Hydrogen diffuses considerably faster through shaft-furnace pellet agglomerates than carbon-based reductants. However, the net reduction kinetics in HyDR remains extremely sluggish for high-quantity steel production, and the hydrogen consumption exceeds the stoichiometrically required amount substantially. Thus, the present study focused on the improved understanding of the influence of spatial gradients, morphology, and internal microstructures of ore pellets on reduction efficiency and metallization during HyDR. For this purpose, commercial DR pellets were investigated using synchrotron high-energy X-ray diffraction and electron microscopy in conjunction with electron backscatter diffraction and chemical probing. Revealing the interplay of different phases with internal interfaces, free surfaces, and associated nucleation and growth mechanisms provides a basis for developing tailored ore pellets that are highly suited for a fast and efficient HyDR.

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Reducing Iron Oxide with Ammonia: A Sustainable Path to Green Steel

Bae

Kim

et al. 2023

Advanced Science

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Iron making is the biggest single cause of global warming. The reduction of iron ores with carbon generates about 7% of the global carbon dioxide emissions to produce ≈1.85 billion tons of steel per year. This dramatic scenario fuels efforts to re‐invent this sector by using renewable and carbon‐free reductants and electricity. Here, the authors show how to make sustainable steel by reducing solid iron oxides with hydrogen released from ammonia. Ammonia is an annually 180 million ton traded chemical energy carrier, with established transcontinental logistics and low liquefaction costs. It can be synthesized with green hydrogen and release hydrogen again through the reduction reaction. This advantage connects it with green iron making, for replacing fossil reductants. the authors show that ammonia‐based reduction of iron oxide proceeds through an autocatalytic reaction, is kinetically as effective as hydrogen‐based direct reduction, yields the same metallization, and can be industrially realized with existing technologies. The produced iron/iron nitride mixture can be subsequently melted in an electric arc furnace (or co‐charged into a converter) to adjust the chemical composition to the target steel grades. A novel approach is thus presented to deploying intermittent renewable energy, mediated by green ammonia, for a disruptive technology transition toward sustainable iron making.

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Hierarchical nature of hydrogen-based direct reduction of iron oxides

Cited by 49 publications

References 58 publications

The Materials Science behind Sustainable Metals and Alloys

The Materials Science behind Sustainable Metals and Alloys

Hydrogen-based direct reduction of iron oxide at 700°C: Heterogeneity at pellet and microstructure scales

Reducing Iron Oxide with Ammonia: A Sustainable Path to Green Steel

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