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WO2025080180A1 - Procédé et système de production de fer réduit directement à froid passivé - Google Patents

Procédé et système de production de fer réduit directement à froid passivé Download PDF

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Publication number
WO2025080180A1
WO2025080180A1 PCT/SE2024/050813 SE2024050813W WO2025080180A1 WO 2025080180 A1 WO2025080180 A1 WO 2025080180A1 SE 2024050813 W SE2024050813 W SE 2024050813W WO 2025080180 A1 WO2025080180 A1 WO 2025080180A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
cooling
reducing
zone
dri
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/SE2024/050813
Other languages
English (en)
Inventor
Niklas KOJOLA
Hedda POUSETTE
Gunilla HYLLANDER
Martin PEI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hybrit Development AB
Original Assignee
Hybrit Development AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hybrit Development AB filed Critical Hybrit Development AB
Publication of WO2025080180A1 publication Critical patent/WO2025080180A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0073—Selection or treatment of the reducing gases
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0086—Conditioning, transformation of reduced iron ores
    • C21B13/0093—Protecting against oxidation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0086—Conditioning, transformation of reduced iron ores
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C21B13/029—Introducing coolant gas in the shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/14—Treatment of metallic powder
    • B22F1/145—Chemical treatment, e.g. passivation or decarburisation

Definitions

  • the present disclosure relates to a process and a system for production of passivated cold direct reduced iron (cDRI).
  • the disclosure further relates to a passivated cold direct reduced iron product obtainable by such a process.
  • DRI Due to its high porosity, low density, large surface area and low thermal conductivity, it has a propensity to undergo rapid corrosion and reoxidation reactions. Many of these reactions are exothermic, leading to self-heating and eventually self-ignition and fires if not controlled. Corrosion and oxidation reactions of DRI can also produce hydrogen, an explosive gas which is lighter than air, and carbon monoxide, a highly toxic gas. These problems are compounded by the fact that DRI is typically relatively weak and tends to break down during handling to produce dust and fines. DRI dust tends to be even more reactive than the bulk DRI and has a high propensity to self-heat and cause fires. For example, DRI dust that is dispersed in air can ignite in a flash fire or explosion.
  • controlled passivation is typically performed by introducing a flowing supply of mildly oxidising gas (3% oxygen) to the DRI in a storage silo. It is recommended that DRI should be aged in this manner for at least 72 hours after production to allow passivation to occur. This is because DRI is most reactive immediately after it is produced, and the rate of reaction with oxygen (air) will decrease by roughly 3 orders of magnitude or lOOOx in the first 72 hours.
  • Such passivation is described in "Direct Reduced Iron (DRI): Guide to Shipping, Handling and Storage (April 2022)” from the International Iron Metallics Association. The same document states that carbon content (in the form of iron carbide/cementite/Fe3C) decreases reactivity of DRI.
  • the inventors of the present invention have identified a number of shortcomings with prior art means of producing DRI that is suitable to handle, transport and store.
  • traditional cold DRI is not particularly amenable to such purposes, and extensive precautions must be taken when shipping such a product.
  • the cold DRI typically requires passivation in a controlled atmosphere for a number of days post-production in order to decrease reactivity to a manageable extent, further adding to the capital- and operating- expenses of the process.
  • passivation may proceed at varying rate depending on ambient temperature, and the quality of passivation obtained after a fixed period of e.g. 72 hours may vary accordingly. Briquetting of DRI to produce HBI effectively addresses such problems, but at the cost of adding additional steps to the manufacturing process, resulting in additional expense.
  • the process comprises the steps:
  • a heated bustle gas to a reducing zone of the direct reduction shaft arrangement, wherein the heated bustle gas comprises greater than 85 vol% hydrogen gas, and wherein the heated bustle gas forms a component part of a reducing gas that reduces the iron ore to hot DRI;
  • cooling gas comprises greater than 85 vol% hydrogen gas and wherein the cooling gas has a water content of at least 0.5 vol%, thereby cooling and passivating the hot DRI to provide passivated cold DRI and heating the cooling gas to provide heated cooling gas;
  • FIG. 2b schematically illustrates a further exemplifying embodiment of a system according to the present disclosure
  • Fig. 4 is a chart showing the oxygen uptake during passivation of a variety of bulk DRI samples.
  • the process may comprise a further step sll2 (denoted as optional in Figure 1) of regulating the water content of the cooling gas to within a predetermined range.
  • the predetermined range may be from about 0.5 vol% to about 5 vol%, such as from about 0.7 vol% to about 2 vol%, such as from about 0.9 vol% to about 1.5 vol%. This ensures a suitable water content in the cooling gas in order to achieve passivation but without negatively impacting the reducing capacity of the gas introduced.
  • reducing gas arranged in fluid communication with the reducing gas inlet, wherein the reducing gas is hydrogen gas
  • a water content control arrangement 241 arranged to regulate the water content of the cooling gas to within a predetermined range prior to it entering the cooling gas inlet.
  • the system is thus adapted to perform the process as disclosed herein.
  • the control device may be manually controllable based upon the output of the water content determination device, or may be automatically controllable based upon the output of the water content determination device. In the case where the control device is automatically controllable, it may comprise a manual override function for the automatic control.
  • the reducing zone and the cooling zone may be arranged in the same direct reduction shaft.
  • Such an arrangement resembles the arrangement typically used in commercial shaft-based direct reduction processes and is advantageous in that only a single shaft is required, thus limiting capital expenditure in the system.
  • the source of cooling gas may be a cooling gas circuit arranged to convey spent cooling gas or spent reducing gas to the cooling gas inlet.
  • the regulation device may be arranged in communication with the cooling gas circuit, optionally a source of water and optionally a source of essentially pure hydrogen.
  • the regulation device regulates the water content of the cooling gas to within a predetermined range by optionally regulating a supply of water and/or a supply of essentially pure hydrogen to the spent cooling gas or reducing gas, based upon an output of the water content determination device.
  • the heated reducing gas 22 also known as "bustle gas” is introduced in order to reduce the iron ore burden.
  • the reducing gas 121 is introduced into the reducing gas inlet 209 arranged at the lower end of the reducing zone, flows mainly upwards counter-current to the burden and exits the shaft as top gas 223, also known as spent reducing gas, at the top gas outlet 224 at an upper end of the shaft.
  • Reduction is typically performed at inlet temperatures of from about 750 °C to about 1000 °C.
  • the temperatures required are typically maintained by heating the reducing gas introduced into the reactor, for example using a heater 225, such as an electric heater.
  • a source of cooling gas 234 is arranged in fluid communication with the cooling gas inlet 235.
  • the cooling gas is hydrogen gas, and the source of cooling gas may for example be the same as the source of reducing gas.
  • a cooling gas 233 from the cooling gas source 234 is provided to a cooling zone 235 of the shaft in order to cool the DRI after reduction and prior to discharge.
  • the cooling zone 235 is typically arranged at a lower end of the direct reduction shaft.
  • the cooling gas may comprise, consist essentially of, or consist of at least 85 vol%, preferably greater than 90 vol%, even more preferably greater than 95 vol% hydrogen gas (vol% determined at normal conditions of 1 atm and 0 °C).
  • a water content control arrangement 241 is arranged to regulate the water content of the cooling gas to within a predetermined range prior to it entering the cooling gas inlet 137.
  • the water content control arrangement 241 comprises a water content determination device 243 (e.g. a moisture sensor), a source of water 247 (e.g. steam source) and a regulation device 245 (e.g. controllable valve).
  • the water content determination device 243 is arranged in communication with the regulation device 245. If a water content outside of the predetermined range is detected, then the regulation device 245 is actuated to raise or lower the amount of water being supplied to the cooling gas from the water supply 247, as appropriate.
  • Metallization is defined in a manner conventional within the art as (Fe m etaiiic / Fe to tai) x 100. Metallization was determined using X-ray diffractometry (XRD), but may also be determined using other methods. Such other methods include:
  • ISO 10276-1:2000 (Chemical analysis of ferrous materials — Determination of oxygen in steel and iron Part 1: Sampling and preparation of steel samples for oxygen determination) in combination with ISO 10276-2:2003 (Chemical analysis of ferrous materials — Determination of oxygen content in steel and iron — Part 2: Infrared method after fusion under inert gas).
  • the DRI produced from three different process points was investigated.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Manufacture Of Iron (AREA)

Abstract

La présente divulgation concerne un procédé et un système de production de fer réduit directement à froid (cDRI) passivé. Le procédé comprend les étapes consistant à : - introduire du minerai de fer dans une entrée de minerai d'un agencement d'arbre de réduction directe (s103) ; - introduire un gaz circulaire chauffé dans une zone de réduction de l'agencement d'arbre de réduction directe, le gaz circulaire chauffé comprenant plus de 85 % en volume d'hydrogène gazeux, et le gaz circulaire chauffé formant une partie constitutive d'un gaz réducteur qui réduit le minerai de fer en DRI chaud (s105) ; - éliminer un gaz réducteur usé de la zone de réduction (s107) ; - introduire un gaz de refroidissement dans une zone de refroidissement de l'agencement d'arbre de réduction directe, le gaz de refroidissement comprenant plus de 85 % en volume d'hydrogène gazeux et le gaz de refroidissement ayant une teneur en eau d'au moins 0,5 % en volume, ce qui permet de refroidir et de passiver le DRI chaud pour fournir du DRI froid passivé et de chauffer le gaz de refroidissement pour fournir un gaz de refroidissement chauffé (s109) ; et - retirer le DRI froid passivé de l'agencement d'arbre de réduction directe (s111). La divulgation concerne en outre un produit de fer réduit directement à froid passivé pouvant être obtenu par un tel procédé.
PCT/SE2024/050813 2023-10-09 2024-09-24 Procédé et système de production de fer réduit directement à froid passivé Pending WO2025080180A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE2351155A SE2351155A1 (en) 2023-10-09 2023-10-09 Process and system for production of passivated cold direct reduced iron
SE2351155-3 2023-10-09

Publications (1)

Publication Number Publication Date
WO2025080180A1 true WO2025080180A1 (fr) 2025-04-17

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Family Applications (1)

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SE (1) SE2351155A1 (fr)
WO (1) WO2025080180A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000049184A1 (fr) * 1999-02-18 2000-08-24 Danieli & C. Officine Meccaniche S.P.A. Procede de reduction directe d'oxydes de fer avec transformation en carbure de fer
US6426036B1 (en) * 1999-10-11 2002-07-30 Danieli & C. Officine Meccaniche Direct reduction device to obtain metal iron with a high content of carbon in the form of carbide
CN107881280A (zh) * 2017-12-22 2018-04-06 江苏省冶金设计院有限公司 一种还原并冷却金属化球团的系统及方法
WO2021225500A1 (fr) 2020-05-04 2021-11-11 Hybrit Development Ab Procédé de production de fer cémenté
CN115976296A (zh) * 2022-12-21 2023-04-18 东北大学 一种还原气循环利用的氢冶金系统及方法
US20230167517A1 (en) * 2020-05-28 2023-06-01 Nippon Steel Corporation Method for producing reduced iron

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844764A (en) * 1973-12-26 1974-10-29 Medrex Corp Process for the continuous passivation of sponge iron particles
ZA762594B (en) * 1975-06-05 1977-04-27 Midrex Corp Method and apparatus for continuous passivation of sponge iron material
US4070180A (en) * 1976-08-23 1978-01-24 United States Steel Corporation Process for the passivation of sponge iron utilizing reducing gases containing free oxygen
SU596627A1 (ru) * 1976-10-11 1978-03-05 Научно-производственное объединение "Тулачермет" Способ получени губчатого железа
GB2112019A (en) * 1981-12-18 1983-07-13 British Steel Corp Reduction of agglomerated iron ore
SE545600C2 (en) * 2021-06-22 2023-11-07 Hybrit Development Ab Hydrogen gas recycling in a direct reduction process
SE547277C2 (en) * 2022-04-01 2025-06-17 Luossavaara Kiirunavaara Ab Method and configuration for producing reduced iron ore material

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000049184A1 (fr) * 1999-02-18 2000-08-24 Danieli & C. Officine Meccaniche S.P.A. Procede de reduction directe d'oxydes de fer avec transformation en carbure de fer
US6426036B1 (en) * 1999-10-11 2002-07-30 Danieli & C. Officine Meccaniche Direct reduction device to obtain metal iron with a high content of carbon in the form of carbide
CN107881280A (zh) * 2017-12-22 2018-04-06 江苏省冶金设计院有限公司 一种还原并冷却金属化球团的系统及方法
WO2021225500A1 (fr) 2020-05-04 2021-11-11 Hybrit Development Ab Procédé de production de fer cémenté
US20230167517A1 (en) * 2020-05-28 2023-06-01 Nippon Steel Corporation Method for producing reduced iron
CN115976296A (zh) * 2022-12-21 2023-04-18 东北大学 一种还原气循环利用的氢冶金系统及方法

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