Sustainable steel through hydrogen plasma reduction of iron ore: process, kinetics, microstructure, chemistry

Replacing carbon by hydrogen is a huge step towards reducing CO2 emissions in the iron- and steel-making industry. The reduction of iron oxides using hydrogen plasma smelting reduction as an alternative to conventional steel-making routes has been studied at Montanuniversitaet Leoben, Austria. The aim of this work was to study the slag formation during the reduction process and the reduction behaviour of iron oxides. Furthermore the reduction behaviour of iron ore during continuous feeding was assessed. Mixtures of iron ore and calcined lime with a basicity of 0, 0.8, 1.6, 2.3, and 2.9 were melted and reduced by hydrogen. The off-gas composition was measured during the operations to calculate the process parameters. The reduction parameters, namely the degree of reduction, degree of hydrogen utilisation, produced iron, and slag, are presented. The results of the batch-charged experiments showed that at the beginning of the reduction process, the degree of hydrogen utilisation was high, and then, it decreased over the operation time. In contrast, during the continuous-feeding experiment, the degree of hydrogen utilisation could be kept approximately constant. The highest degrees of reduction and hydrogen utilisation were obtained upon the application of a slag with a basicity of 2.3. The experiment showed that upon the continuous feeding of iron ore, the best conditions for the reduction process using hydrogen could be applied.

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Physics and Chemistry of Solid State Direct Reduction of Iron Ore by Hydrogen Plasma

Фізика і хімія твердого тіла ◽

10.15330/pcss.22.2.292-300 ◽

2021 ◽

Vol 22 (2) ◽

pp. 292-300

Author(s):

Kali Charan Sabat

Keyword(s):

Solid State ◽

Large Scale ◽

Iron Ore ◽

Direct Reduction ◽

Hydrogen Plasma ◽

Standard Free Energy ◽

Reduction Process ◽

Capital Investments ◽

State Reduction ◽

Reduction Of Iron

Presently, Iron is produced from iron ores by using carbon from coal. The production process is consisting of many stages. The involvement of multi-stages needs high capital investments, large-scale equipments, and produces large amounts of carbon dioxide (CO2) responsible for environmental pollution. There have been significant efforts to replace carbon with hydrogen (H2). Although H2 is the strongest reductant, it still also has thermodynamic and kinetic limitations. However, these thermodynamic and kinetic limitations could be removed by hydrogen plasma (HP). HP comprises rovibrationally excited molecular, atomic, and ionic states of hydrogen. All of them contribute to thermodynamic advantage by making the Gibbs standard free energy more negative, which makes the reduction of iron oxides feasible at low temperatures. Apart from the thermodynamic advantage, these excited species increase the internal energy of HP, which reduces the activation energy, thereby making the reduction easier and faster. Apart from the thermodynamic and kinetic advantage of HP, the byproduct of the reaction is environmentally benign water. This review discusses the physics and chemistry of iron ore reduction using HP, emphasizing the solid-state reduction of iron ore. HP reduction of iron ore is a high potential and attractive reduction process.

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Slag Formation During Reduction of Iron Oxide Using Hydrogen Plasma Smelting Reduction

10.20944/preprints202001.0337.v1 ◽

2020 ◽

Author(s):

Masab Naseri Seftejani ◽

Johannes Schenk ◽

Daniel Spreitzer ◽

Michael Andreas Zarl

Keyword(s):

Iron Oxides ◽

Iron Ore ◽

Hydrogen Plasma ◽

Reduction Process ◽

Slag Formation ◽

Smelting Reduction ◽

Steel Making ◽

Reduction Of Iron ◽

Reduction Behaviour ◽

Continuous Feeding

Replacing carbon by hydrogen is a huge step towards reducing CO2 emissions in the iron- and steel-making industry. The reduction of iron oxides using hydrogen plasma smelting reduction as an alternative to conventional steel-making routes has been studied at Montanuniversitaet Leoben, Austria. The aim of this work was to study the slag formation during the reduction process and the reduction behaviour of iron oxides. Furthermore, the reduction behaviour of iron ore during continuous feeding was assessed. Mixtures of iron ore and calcined lime with a basicity of 0, 0.8, 1.6, 2.3, and 2.9 were melted and reduced by hydrogen. The off-gas composition was measured during the operations to calculate the process parameters. The reduction parameters, namely the degree of reduction, degree of hydrogen utilisation, produced iron, and slag, are presented. The results of the batch-charged experiments showed that at the beginning of the reduction process, the degree of hydrogen utilisation was high, and then, it decreased over the operation time. In contrast, during the continuous-feeding experiment, the degree of hydrogen utilisation could be kept approximately constant. The highest degrees of reduction and hydrogen utilisation were obtained upon the application of a slag with a basicity of 2.3. The experiment showed that upon the continuous feeding of iron ore, the best conditions for the reduction process using hydrogen could be applied.

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Effects of reductant type on coal-based direct reduction of iron ore tailings

Annales de Chimie Science des Matériaux ◽

10.3166/acsm.42.453-466 ◽

2018 ◽

Vol 42 (3) ◽

pp. 453-466

Author(s):

Wei WANG ◽

Pengfei YE ◽

Xiaoli ZHOU ◽

C WANG ◽

Zekun HUO ◽

...

Keyword(s):

Iron Ore ◽

Direct Reduction ◽

Iron Ore Tailings ◽

Reduction Of Iron ◽

Direct Reduction Of Iron

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Assessment of Utilization Potential of Biomass Volatiles and Biochar as a Reducing Agent for Reduction of Iron Ore Pellets

SSRN Electronic Journal ◽

10.2139/ssrn.3932836 ◽

2021 ◽

Author(s):

Dipika Das ◽

Shalini Gautam

Keyword(s):

Iron Ore ◽

Reducing Agent ◽

Iron Ore Pellets ◽

Ore Pellets ◽

Reduction Of Iron ◽

Utilization Potential

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Thermodynamic of Liquid Iron Ore Reduction by Hydrogen Thermal Plasma

Metals ◽

10.3390/met8121051 ◽

2018 ◽

Vol 8 (12) ◽

pp. 1051 ◽

Cited By ~ 4

Author(s):

Masab Naseri Seftejani ◽

Johannes Schenk

Keyword(s):

Iron Oxide ◽

Liquid Iron ◽

Thermal Plasma ◽

Iron Ore ◽

Hydrogen Plasma ◽

Reduction Rate ◽

Plasma Arc ◽

Ionization Degree ◽

Reduction Reactions ◽

Plasma State

The production of iron using hydrogen as a reducing agent is an alternative to conventional iron- and steel-making processes, with an associated decrease in CO2 emissions. Hydrogen plasma smelting reduction (HPSR) of iron ore is the process of using hydrogen in a plasma state to reduce iron oxides. A hydrogen plasma arc is generated between a hollow graphite electrode and liquid iron oxide. In the present study, the thermodynamics of hydrogen thermal plasma and the reduction of iron oxide using hydrogen at plasma temperatures were studied. Thermodynamics calculations show that hydrogen at high temperatures is atomized, ionized, or excited. The Gibbs free energy changes of iron oxide reductions indicate that activated hydrogen particles are stronger reducing agents than molecular hydrogen. Temperature is the main influencing parameter on the atomization and ionization degree of hydrogen particles. Therefore, to increase the hydrogen ionization degree and, consequently, increase of the reduction rate of iron ore particles, the reduction reactions should take place in the plasma arc zone due to the high temperature of the plasma arc in HPSR. Moreover, the solubility of hydrogen in slag and molten metal are studied and the sequence of hematite reduction reactions is presented.

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