A Review on the Kinetics of Iron Ore Reduction by Hydrogen

Heidari, Aidin; Niknahad, Niusha; Iljana, Mikko; Fabritius, Timo

doi:10.3390/ma14247540

Cited by 78 publications

(39 citation statements)

References 64 publications

(97 reference statements)

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“…At 1100 °C, new phases exist, as seen in the XRD results ( Figure 4 and Figure 5 ); brownmillerite and wüstite are present in both durations 0.5 and 2.5 h. These phases indicate incomplete reduction of iron compounds and are most present in the shortest experiment, reduction 5 (0.5 h). Kinetics and thermodynamics suggest that reduction reaction rate should increase with temperature [ 20 , 26 ]. However, SEM images of reduction experiment 6 ( Figure 10 ) show that the sample has a semi-molten phase throughout the pellet.…”

Section: Discussionmentioning

confidence: 99%

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Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

et al. 2022

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The hydrogen reduction of bauxite residue lime pellets at elevated temperatures was carried out to recover iron and alumina from the bauxite residue in a new process route. Prior to the H2 reduction, oxide pellets were initially prepared via the mixing of an industrial bauxite residue with fine calcite powder followed by calcination and high-temperature sintering. The chemical, compositional, and microstructural properties of both oxide and reduced pellets were studied by advanced characterization techniques. It was found that iron in the oxide pellets is mainly in the form of brownmillerite, and calcium–iron–titanate phases, while upon reduction they are converted to wüstite and shulamitite intermediate phases and further to metallic iron. Moreover, it was found that the reduction at lower temperature of 1000 °C is faster than that at higher temperatures of 1100 °C and 1200 °C. The slower rate and extent of reduction at the higher temperatures is attributed to the porosity loss and reduction mechanism change to a diffusion-controlled process step. In addition, it was found that Al-containing phases in the raw materials are converted mainly to gehlenite in sintered pellets and further to the leachable mayenite phase. The alkaline leaching of selected reduced pellets by a sodium carbonate solution yielded up to 87% Al recovery into the solution, while the metallic iron was not affected.

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Section: Discussionmentioning

confidence: 99%

“…The reduction of iron with hydrogen has been observed in recent studies [ 18 , 19 , 20 ]. In bauxite, iron is mainly found in the oxide form called hematite (Fe 2 O 3 ), while lower quantity of goethite, FeOOH, may co-exist.…”

Section: Introductionmentioning

confidence: 97%

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

et al. 2022

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“…The time of completion of the last reduction states (FeO!Fe) is the slowest of all. [15] The proposed kinetic scheme consists of 14 reactions, all of which are first-order reaction. Among them, 13 are heterogeneous and one is a homogeneous reaction (reaction 19).…”

Section: Reaction Schemesmentioning

confidence: 99%

“…FeO ðsÞ þ C ðsÞ ! Fe ðsÞ þ CO ðgÞ (15) Now, considering the stoichiometry associated with these reactions, the theoretical weight loss in each of the states is shown in Table 1. This clearly shows that the maximum weight loss or removal of oxygen happens at the last stage.…”

Section: Reaction Schemesmentioning

confidence: 99%

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres

Ali

Fradet

Riedel

2022

steel research int.

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The steel industry currently faces significant challenges. These are enormous environmental impacts, material usage, energy consumption, and byproducts of the processes. [1] In 2020, the total crude steel production was 1869 million tons (Mt). [2] The conventional blast furnace-basic oxygen furnace (BF-BOF) route produces 70% of the global crude steel, [3] utilizing coke to produce iron by reducing iron ore, which emits high amounts of CO 2 in the environment. Steel production contributed 6.7% of the global anthropogenic emissions of CO 2 in 2020, and the average emission is estimated to be 1.8 t CO 2 / per t steel. [4] This corresponds to %3.46 Gt CO 2 per year, eventually leading to even higher annual emissions in 2050 due to the growing steel demand. Given this high level of CO 2 emissions, steel production cannot rely on continuous process optimization but instead, needs fundamental technological changes to meet future emission limitations.Under these circumstances, the direct reduction (DR) process of iron oxide is a promising technology to reduce the CO 2 emissions where hematite (Fe 2 O 3 ) is reduced by syngas (H 2 /CO-mixture) or even with pure hydrogen (H 2 ). Many mathematical models have been proposed in the literature to predict the gaseous reduction behavior of iron oxide. However, due to a large number of influencing factors in the direct reduction process, for example, gas composition, operating pressure, temperature, or solid material characteristics (porosity, tortuosity, grain size, gangue contents, mineralogy, etc.), uncertainty is relatively high. Researchers usually try to balance between model simplicity and accuracy (agreement with experimental data). To avoid the inherent complexity of the direct reduction process, McKewan [5] developed a simple one-interface shrinking core model by considering the interface chemical reaction as the rate-limiting step. They concluded while validating against their data that diffusion and chemical reaction should be considered simultaneously. Tsay et al. [6] developed a model based on a three-interface shrinking core model for H 2 /CO mixtures, considering the same diffusivities and mass transfers for reactants and products. However, this approach has the evident weakness of assuming a distinct sharp interface between different solid oxides. A transient isothermal model based on the grain model has been proposed by Valipour et al. [7] to simulate a porous hematite pellet's thermal and kinetic behavior in a syngas environment. They showed how models not considering the film resistances deviate systematically from the experimental data.Aside from the fundamental mathematical approach, the chemical kinetics of reduction of iron oxide with H 2 /CO mixtures has not been adequately investigated, especially the carbon deposition phenomena. Turkdogan et al. [8] studied the kinetics of direct reduction process of iron oxide using hydrogen. They found out that the transformation process of hematite to iron is mediated by magnetite (Fe 3 O 4 ) and wüstite (Fe (1Ày) O).

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“…However, these industries are looking to make these processes more environmentally friendly by establishing new technologies (Kim et al, 2022). The use of hydrogen as the iron ore reducing agent is one of the prominent techniques in direct reduction plants (Heidari et al, 2021). Green hydrogen as a reducing agent in such plants can have great economic and environmental impacts.…”

Section: Production Of Green Steel and Green Ironmentioning

confidence: 99%

An overview of the socio-economic impacts of the green hydrogen value chain in Southern Africa

Hamukoshi

Mama

Shimanda

et al. 2022

J. energy South. Afr.

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The green hydrogen economy offers synthetic green energy with significant impacts and is environmentally friendly compared to current fossil-based fuels. Exploration of green hydrogen energy in Southern Africa is still in the initial stages in many low-resourced settings aiming to benefit from sustainable green energy. At this early stage, potential benefits to society are yet to be understood. That is why the socio-economic impact of green hydrogen energy must be explored. This paper reviews the current literatures to describe the potential socio-economic effects in the Southern African Development Community (SADC). The review supports the view that green hydrogen will be beneficial and have great potential to revolutionise agricultural and industrial sectors, with advanced sustainable changes for both production and processing. This paper also examines how sustainable green hydrogen energy production in Southern Africa will provide economic value in the energy export sector around the world and support climate change initiatives. Further, it discusses the impacts of the green hydrogen value addition chain and the creation of green jobs, as well as the need for corresponding investments and policy reforms. It is also noted that the green hydrogen economy can contribute to job losses in fossil fuel-based industries, so that the workforce there may need re-skilling to take up green jobs. Such exchanges may deter efforts towards poverty alleviation and economic growth in SADC.

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A Review on the Kinetics of Iron Ore Reduction by Hydrogen

Cited by 78 publications

References 64 publications

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres

An overview of the socio-economic impacts of the green hydrogen value chain in Southern Africa

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A Review on the Kinetics of Iron Ore Reduction by Hydrogen

Cited by 78 publications

References 64 publications

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery

Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H2/CO Atmospheres

An overview of the socio-economic impacts of the green hydrogen value chain in Southern Africa

Contact Info

Product

Resources

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Kinetic Mechanism Development for the Direct Reduction of Single Hematite Pellets in H₂/CO Atmospheres