Ironmaking with Ammonia at Low Temperature

Hosokai, Sou; Kasiwaya, Yoshiaki; Matsui, Kosuke; Okinaka, Noriyuki; Akiyama, Tomohiro

doi:10.1021/es102910q

Cited by 18 publications

(11 citation statements)

References 29 publications

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“…The experimental apparatus is described in detail elsewhere 18) but the main features are as follows. The apparatus consists of mass flow controllers, a tubular fixed-bed reactor, a temperature controller, and a quadrupole mass spectrometer (QMS) for analyzing gaseous compounds at the reactor downstream.…”

Section: Methodsmentioning

confidence: 99%

Reduction and Nitriding Behavior of Hematite with Ammonia

et al. 2015

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This paper describes the reduction and nitriding behavior of hematite with ammonia in the context of ironmaking. The effects of temperature and ammonia concentration on the products were investigated. In the temperature range from 793 to 863 K, hematite was directly reduced to magnetite by ammonia (1/2Fe2O3 + 1/9NH3 → 1/3Fe3O4 + 1/6H2O + 1/18N2). The ammonia started to decompose at 873 K, triggered by the generation of α-Fe. Magnetite was reduced mainly to iron by hydrogen generated from the decomposition of ammonia (1/3Fe3O4 + 4/3H2 → Fe + 4/3H2O). According to in-situ X-ray diffraction (XRD) measurements, α-Fe was immediately nitrided to an ε-Fe 3-x N (0 ≤ x ≤ 1) phase, and the N/Fe atomic ratio decreased gradually with increasing temperatures. The rate of hematite reduction increased with the ammonia concentration for 5% to 20% NH3, but plateaus for NH3 concentrations greater than 20%. This was attributed to the mechanism of ammonia decomposition; the amount of hydrogen generated also plateaus at ammonia concentrations above 20%. The reduction rate was therefore limited by the rate at which hydrogen was generated during ammonia decomposition. The N content of the product was affected not only by the temperature but also by the nitriding potential (KN = P NH 3 /P H 2 3/2 ). The nitriding potential increased with increasing ammonia concentrations and decreasing temperatures. The addition of nitrogen gas to the reactive gas inhibited ammonia decomposition and increased the nitrogen potential and N content of the product.

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Section: Methodsmentioning

confidence: 99%

Reduction and Nitriding Behavior of Hematite with Ammonia

et al. 2015

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“…It has been reported that the nitridation of metal oxides can involve the five processes below, depending on the reaction conditions such as temperature. 43,44 NH 3 decomposition: Nitridation:…”

Section: Acs Energy Lettersmentioning

confidence: 99%

“…The annealing effect in ammonia at different temperatures can therefore be concluded as follows: NiCo 2 O 4 is transferred to Ni-doped CoN at 250 °C, Ni-doped Co 2 N at 300 °C, Ni-doped Co–Co 2 N at 350 °C, and Ni-doped Co 3 N at 400 °C. It has been reported that the nitridation of metal oxides can involve the five processes below, depending on the reaction conditions such as temperature. , …”

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confidence: 99%

Ni-Doped Cobalt–Cobalt Nitride Heterostructure Arrays for High-Power Supercapacitors

et al. 2018

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Metal nitrides are widely recognized as a class of desirable supercapacitor electrode materials owing to their high electrical conductivity and structural stability. Embedding metal nanoparticles in nitrides can further enhance the conductivity for electron transport. Herein, a heterostructure consisting of Ni-doped Co–Co2N is synthesized by simple thermal annealing of metal–organic framework (MOF)-derived NiCo2O4 in ammonia atmosphere, in the process of which the MOF-derived two-dimensional (2D) nanoflake arrays were well retained, and the metal–metal nitride heterostructure was well established when annealed at 350 °C. Benefiting from the MOF-derived 2D nanoflake morphology and the metal-metal nitride heterostructure, the Ni-doped Co–Co2N delivers a specific capacity of 361.93 C/g. A full cell test has been conducted using Ni-doped Co–Co2N as the positive electrode and porous carbon as the negative electrode, and it shows an energy density of 20.4 Wh/kg at the power density of 9.85 kW/kg with 82.4% of initial energy density being retained after 5000 cycles.

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“…There is also a geopolitical dimension to hydrogen and visions of international trade, either of hydrogen or of ammonia NH 3 , into which H 2 can easily be converted and thus more easily transported: at the end of the pipe or of the sea lane, NH 3 can be converted back to H 2 or used as such, as it is also an energy carrier with a broad scope of possible applications, including for producing steel [97,98].…”

Section: More Holistic Approaches and Considerationsmentioning

confidence: 99%

Hydrogen steelmaking, part 2: competition with other net-zero steelmaking solutions – geopolitical issues

Birat

Patisson

Mirgaux

2021

Matériaux & Techniques

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Hydrogen direct reduction is one of the technological process solutions for making steel, explored in the framework of reducing GHG emissions from the steel sector (Net-Zero steel). However, there are many other solutions, which have been explored since the 1980s or earlier. The present paper starts by comparing all these different options in terms of 3 criteria: energy needs, GHG emissions and total production cost of steel. The extensive simulations carried out as part of the ULCOS Program, which are still fully valid, indeed show that, while energy is always rather close to the efficient integrated steel mill benchmark (within 15–20%), there are a series of solutions for significantly cutting GHG emissions, some of which even leading to negative emissions. Two families of solutions can usefully be compared with each other, as they are both based on the use of electricity: hydrogen direct reduction, from green hydrogen generated from green electricity, and electrolysis of iron ore, such as the ΣIDERWIN process, also based on zero-carbon electricity. They are quite close with regards to the 3 above criteria, with a slight advantage for electrolysis. Focusing now on hydrogen steelmaking, the process developed over the last 70 years: the H-Iron process was first explored in 1957 at laboratory level, then it was followed by an industrial first plant in the late 1980s, which did not fully deliver (CIRCORED); a sub-project within ULCOS (2000s) followed, then some projects in Germany and Austria (SALCOS, SUSTEEL, MATOR, based on direct reduction and smelting reduction, 2010s) and then, very recently, occurred an explosion of projects and announcements of industrial ventures, both for generating hydrogen and for producing DRI, located in Europe, Russia and China. Broader questions are then tackled: how much hydrogen will be called upon, compared to today and future needs, regarding in particular H2-e-mobility; carbon footprint and costs; maturity of the various processes; and geopolitical issues, such as possible locations of H2-generation and H2-steel production.

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Ironmaking with Ammonia at Low Temperature

Cited by 18 publications

References 29 publications

Reduction and Nitriding Behavior of Hematite with Ammonia

Reduction and Nitriding Behavior of Hematite with Ammonia

Ni-Doped Cobalt–Cobalt Nitride Heterostructure Arrays for High-Power Supercapacitors

Hydrogen steelmaking, part 2: competition with other net-zero steelmaking solutions – geopolitical issues

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