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US20120240725A1 - Carbon composite agglomerate for producing reduced iron and method for producing reduced iron using the same - Google Patents

Carbon composite agglomerate for producing reduced iron and method for producing reduced iron using the same Download PDF

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Publication number
US20120240725A1
US20120240725A1 US13/386,158 US201013386158A US2012240725A1 US 20120240725 A1 US20120240725 A1 US 20120240725A1 US 201013386158 A US201013386158 A US 201013386158A US 2012240725 A1 US2012240725 A1 US 2012240725A1
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United States
Prior art keywords
agglomerate
reduced iron
carbon composite
mass
sio
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Abandoned
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US13/386,158
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English (en)
Inventor
Takeshi Sugiyama
Shohei Yoshida
Kyoichiro Fujita
Ryota Misawa
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Kobe Steel Ltd
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Kobe Steel Ltd
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Assigned to KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) reassignment KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FUJITA, KYOICHIRO, MISAWA, RYOTA, SUGIYAMA, TAKESHI, YOSHIDA, SHOHEI
Publication of US20120240725A1 publication Critical patent/US20120240725A1/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/02—Working-up flue dust
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/10—Making spongy iron or liquid steel, by direct processes in hearth-type 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
    • C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/242—Binding; Briquetting ; Granulating with binders
    • C22B1/243—Binding; Briquetting ; Granulating with binders inorganic
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/242—Binding; Briquetting ; Granulating with binders
    • C22B1/244—Binding; Briquetting ; Granulating with binders organic
    • C22B1/245—Binding; Briquetting ; Granulating with binders organic with carbonaceous material for the production of coked agglomerates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a carbon composite agglomerate used as a material for a moving hearth furnace for producing reduced iron, and a method for producing reduced iron using such a carbon composite agglomerate.
  • Patent Literatures 1 to 3 Various techniques for producing reduced iron by reducing carbon composite agglomerates through heating with a rotary hearth furnace have been proposed (for example, refer to Patent Literatures 1 to 3).
  • Such reduced iron produced is used as an iron material for a blast furnace, a converter, an electric furnace, or the like.
  • the reduced iron is demanded to have a C content as high as possible for improving the energy efficiency of such a furnace and a strength as high as possible for not producing powder.
  • crushing strength is generally used.
  • 180 kgf/briquette about 1760 N/briquette
  • an object of the present invention is to provide a carbon composite agglomerate used as a material for a moving hearth furnace for producing reduced iron, the carbon composite agglomerate providing reduced iron having a sufficiently high carbon content and an increased crushing strength; and a method for producing reduced iron using such a carbon composite agglomerate.
  • An invention according to Claim 1 is a carbon composite agglomerate for producing reduced iron, the carbon composite agglomerate being used as a material for a moving hearth furnace for producing reduced iron, wherein, in the carbon composite agglomerate, a total content of SiO 2 , Al 2 O 3 , CaO, and MgO is 7 to 15 mass %, a MgO content is 0.1 to 6 mass %, a mass ratio of Al 2 O 3 /SiO 2 is 0.34 to 0.52, a mass ratio of CaO/SiO 2 is 0.25 to 2.0, and a C content is such that 1 to 9 mass % of C remains in reduced iron produced from the carbon composite agglomerate.
  • An invention according to Claim 2 is the carbon composite agglomerate for producing reduced iron according to Claim 1 , having a porosity of 37.5% or less.
  • An invention according to Claim 3 is the carbon composite agglomerate for producing reduced iron according to Claim 1 or 2 , wherein an average grain size d50 of a carbonaceous material in the carbon composite agglomerate measured by a laser diffraction scattering grain size distribution measurement method is 30 ⁇ m or less.
  • An invention according to Claim 4 is the carbon composite agglomerate for producing reduced iron according to any one of Claims 1 to 3 , at least containing ironmaking dust.
  • An invention according to Claim 5 is a method for producing reduced iron by reducing the carbon composite agglomerate for producing reduced iron according to any one of Claims 1 to 4 , through heating with a moving hearth furnace, wherein the moving hearth furnace is divided into a plurality of zones in a moving direction of a hearth and a final zone of the plurality of zones has an oxidizing atmosphere.
  • An invention according to Claim 6 is the method for producing reduced iron according to Claim 5 , wherein the oxidizing atmosphere of the final zone has a gas oxidation degree OD of 1.0 or more, and
  • the slag component composition of a carbon composite agglomerate and the amount of C remaining in a reduced iron product obtained by reducing the carbon composite agglomerate be in specific ranges, reduced iron having a sufficiently high carbon content and an increased crushing strength can be produced.
  • FIG. 1 is a graph illustrating the influence of the slag component composition of carbon composite briquettes on the crushing strength of reduced iron.
  • FIG. 2 illustrates a FeO—Ca—O—Al 2 O 3 —SiO 2 phase diagram for explaining the relationship between the slag component of carbon composite briquettes and the liquidus temperature.
  • FIG. 3 illustrates a MgO—Ca—O—Al 2 O 3 —SiO 2 phase diagram for explaining the relationship between the slag component of carbon composite briquettes and the liquidus temperature.
  • FIG. 4( a ) is a sectional view illustrating the internal structure of a carbon composite briquette reduced in a reducing atmosphere
  • FIG. 4( b ) is a sectional view illustrating the internal structure of a carbon composite briquette reduced in an oxidizing atmosphere.
  • FIG. 5 is a graph illustrating the relationship between the C content of reduced iron and the crushing strength of reduced iron.
  • FIG. 6 is a graph illustrating the relationship between the porosity of carbon composite briquettes and the crushing strength of reduced iron.
  • FIG. 7 is a graph illustrating the grain size distribution of blast-furnace wet dust.
  • FIG. 8 illustrates blast-furnace wet dust observed with an electron microscope.
  • a feature of the present invention is to make the slag component composition and carbon content of carbon composite briquettes be in specific ranges. As a result, a reduced iron product that is more suitable as an iron material for a blast furnace, an electric furnace, a converter, or the like, has a sufficiently high carbon content, and has an increased crushing strength can be obtained.
  • the following carbon composite briquettes are preferably used.
  • the total content of SiO 2 , Al 2 O 3 , CaO, and MgO is 7 to 15 mass %; the MgO content is 0.1 to 6 mass %; the mass ratio of Al 2 O 3 /SiO 2 is 0.34 to 0.52; and the mass ratio of CaO/SiO 2 is 0.25 to 2.0 (more preferably 0.25 to 1.5, particularly preferably 0.25 to 1.0).
  • the C content of the carbon composite briquettes is adjusted such that 1 to 9 mass % of C remains in a reduced iron product obtained by reducing the carbon composite briquettes.
  • the total content of SiO 2 , Al 2 O 3 , CaO, and MgO in carbon composite briquettes substantially equals to the slag component content of the carbon composite briquettes.
  • the slag component content of carbon composite briquettes is excessively low, the effect of promoting sintering of metallic iron by melting of the slag component is not provided.
  • the slag component content of carbon composite briquettes is excessively high, reduced iron obtained by reducing the carbon composite briquettes has an excessively high slag content, which inhibits the sintering reaction of metallic iron to decrease the strength of the reduced iron.
  • the reduced iron has a low iron grade.
  • the total content of SiO 2 , Al 2 O 3 , CaO, and MgO in carbon composite briquettes is preferably in the range of 7 to 15 mass %.
  • the upper limit of the MgO content is defined as 6 mass %.
  • the lower limit of the MgO content is defined as 0.1 mass %.
  • Mass Ratio of Al 2 O 3 /SiO 2 0.34 to 0.52; and Mass Ratio of CaO/SiO 2 : 0.25 to 2.0 (More Preferably 0.25 to 1.5, Particularly Preferably 0.25 to 1.0)>
  • the inventors of the present invention first investigated the influence of the slag component composition on the crushing strength of a reduced iron product by performing the following heating reduction tests.
  • Blend materials having various slag component compositions were prepared by adjusting blending proportions of iron ore and an ironmaking dust mixture obtained by mixing ironmaking dusts including blast-furnace dust.
  • the blend materials were formed into carbon composite briquettes having the shape of a pillow and a volume of 6 to 7 cm 3 with a twin-roll briquetting machine.
  • the briquettes were dried with a dryer so as to have a water content of 1 mass % or less.
  • Examples of the chemical composition of the dried briquettes (hereafter, referred to as “dry briquettes”) are shown in Table 1.
  • “T. C” represents the total carbon content
  • T. Fe represents the total iron content
  • M. Fe represents a metallic-iron content
  • T. Fe includes Fe 2 O 3 , FeO, and “M. Fe”; Na, K, and Pb are not present in the form of atoms, but are present in the form of oxides and the like.
  • the heating reduction test in which N 2 (100%) gas was passed to provide a reducing gas atmosphere around the briquettes simulates reduction conditions in a reducing atmosphere in an actual rotary hearth furnace; and the reduction test in which the CO 2 -containing gas was passed to provide an oxidizing gas atmosphere around the briquettes simulates reduction conditions in the presence of combustion exhaust gas in an actual rotary hearth furnace.
  • the measurement results are illustrated in FIG. 1 .
  • the inventors have found that, by making the mass ratio of Al 2 O 3 /SiO 2 be in the range of 0.34 to 0.52 and the mass ratio of CaO/SiO 2 be in the range of 0.25 to 1.0, the crushing strength of reduced iron is further increased to 180 kgf/briquette (about 1760 N/briquette) or more.
  • the specific ranges are found to correspond to a region in which the liquidus temperature is a relatively low temperature of about 1200° C. to 1300° C.
  • the slag component CaO, Al 2 O 3 , and SiO 2
  • the wustite FeO
  • the specific ranges correspond to a region that does not include the eutectic point P, which is a minimum melting point, and is located slightly away from the eutectic point P toward a high-temperature side.
  • the reason for this is probably as follows.
  • the slag component of carbon composite briquettes is made to have a composition close to the eutectic point P in FIG. 2 , the slag component reacts with wustite (FeO) and the entire amount of the slag component rapidly melts.
  • wustite FeO
  • Such rapid melting of the entire amount of the slag component results in the formation of a large number of cavities in the briquettes, which inhibits promotion of sintering of metallic iron. Thus, high strength is not achieved.
  • the slag component of carbon composite briquettes be in the specific ranges in FIG. 2 , a solid-liquid coexistent state in which not the entire amount of but a portion of the slag component melts is achieved; as a result, the formation of cavities due to melting of slag is suppressed and sintering of metallic iron can be promoted.
  • the strength development of reduced iron is achieved not by a slag phase but by the sinter structure of metallic iron.
  • the specific ranges are plotted in the MgO (constant: 5 mass %)-Ca—O—Al 2 O 3 —SiO 2 phase diagram, the specific ranges are found to correspond to a region in which the liquidus temperature is about 1300° C. to 1400° C. This liquidus temperature is about 100° C. higher than that in the case in FIG. 2 where FeO is present. This shows that the presence of wustite (FeO) is desirable to facilitate melting of the slag component.
  • wustite FeO
  • CaO/SiO 2 of carbon composite briquettes is particularly preferably in the range of 0.25 to 1.0.
  • a portion of CaO melts and CaO/SiO 2 of molten slag can satisfy the range of 0.25 to 1.0.
  • the preferred range of CaO/SiO 2 is defined as the range of 0.25 to 2.0 (more preferably 0.25 to 1.5).
  • composition of the slag component of carbon composite briquettes can be adjusted by, for example, adjusting blending proportions of a plurality of ironmaking dusts having different slag component compositions and iron ore, or adjusting the amount of CaO source added such as limestone or burnt lime.
  • the amount of C remaining in a reduced iron product obtained by reducing carbon composite briquettes is preferably in the range of 1 to 9 mass %.
  • the amount of C remaining in a reduced iron product can be adjusted by adjusting the amount of a carbonaceous material (carbon content) of carbon composite briquettes: for example, in the production of carbon composite briquettes, by adjusting the blending proportion of blast-furnace dust having a high carbon content or adjusting the amount of a carbonaceous material added such as coal or coke powder.
  • the carbon content Xc of carbon composite briquettes should be specifically set with the following formula (1).
  • XcT (12/16) ⁇ Xo
  • XcT represents a theoretical C amount necessary for completely reducing iron oxide and zinc oxide in the carbon composite briquettes to the metals
  • XcR represents the amount of C remaining in reduced iron when the iron oxide and zinc oxide have been completely reduced to the metals with the theoretical C amount XcT
  • Xo represents the total amount of oxygen of iron oxide and oxygen of zinc oxide in the carbon composite briquettes.
  • the theoretical C amount is defined on the premise that reduction of 1 mole of oxygen of iron oxide or zinc oxide requires 1 mole of carbon.
  • CO gas is generated by reduction (direct reduction) of iron oxide or zinc oxide with carbon and the CO gas causes reduction (gas reduction) of iron oxide or zinc oxide to proceed; accordingly, the amount of carbon required for reduction of 1 mole of oxygen of iron oxide or zinc oxide is less than 1 mole.
  • carbon composite briquettes are heated by combustion with burners in a moving hearth furnace, the combustion gas consumes a portion of a carbonaceous material (carbon) in the carbon composite briquettes and the portion is not used for reduction of iron oxide or zinc oxide.
  • the decrease in the C consumption due to the gas reduction substantially cancels out the increase in the C consumption due to burner combustion gas. Accordingly, the theoretical C amount can be regarded as a C amount actually required for reduction.
  • the presence of wustite (FeO) in carbon composite briquettes is desirable for facilitating melting of the slag component.
  • the rotary hearth furnace is preferably divided into a plurality of zones in the moving direction of the hearth and the final zone of the plurality of zones preferably has an oxidizing atmosphere.
  • the final zone By making the final zone have an oxidizing atmosphere, as illustrated in FIG. 4( b ), metallic iron in the near-surface regions of reduced iron obtained by reducing carbon composite briquettes is reoxidized to form wustite (FeO).
  • wustite FeO
  • FIG. 4 shows comparison in terms of internal structure between the reduced iron obtained by reducing a carbon composite briquette in the reducing atmosphere ( FIG. 4( a )) and the reduced iron obtained by reducing a carbon composite briquette in the oxidizing atmosphere ( FIG. 4( b )) in the heating reduction tests. Bonding between metallic iron grains proceeds in both of the atmospheres; however, in the reduced iron obtained by reduction in the oxidizing atmosphere ( FIG. 4( b )), molten wustite grains (gray) are present in the near-surface region of the briquette and the thickness of bonded metallic iron (white) becomes large. This shows that sintering of metallic iron has proceeded in the reduced iron obtained by reduction in the oxidizing atmosphere ( FIG.
  • FIG. 4( b ) compared with the reduced iron obtained by reduction in the reducing atmosphere ( FIG. 4( a )).
  • the reduced iron in FIG. 4( a ) had a crushing strength of about 300 kgf/briquette (about 2940 N/briquette), whereas the reduced iron in FIG. 4( b ) had a crushing strength of more than 600 kgf/briquette (about 5880 N/briquette).
  • the final zone is preferably made to have an oxidizing atmosphere having a gas oxidation degree OD of 1.0 or more.
  • the gas oxidation degree of the atmosphere of the final zone can be adjusted by changing, for example, the air-fuel ratio of a burner.
  • the Embodiment 1 above describes an example in which the physical internal structure of the carbon composite briquettes is not particularly limited.
  • the physical internal structure of carbon composite briquettes in particular, by making the porosity of carbon composite briquettes be in a specific range, even when the amount of carbon remaining in a reduced iron product obtained by reducing the carbon composite briquettes is large, a sufficiently high crushing strength can be achieved with certainty.
  • carbon composite briquettes having a porosity of 37.5% or less are preferably used.
  • the inventors of the present invention investigated the influence of various parameters on the crushing strength of reduced iron obtained by preparing carbon composite briquettes from ironmaking dust and reducing the carbon composite briquettes under the same test conditions as in Embodiment 2.
  • FIG. 5 illustrates the relationship between the C content of reduced iron and the crushing strength of reduced iron.
  • reduced irons having a crushing strength of 180 kgf/briquette (about 1760 N/briquette) or more which are more suitable as iron materials for a blast furnace and the like, are a reduced iron [region A] having a low C content (C: 1 mass % or more and less than 4 mass %) and a reduced iron [region B] having a high C content (C: 4 mass % or more).
  • the reduced iron in the region A is an extension of common general technical knowledge (line L in the figure) in which the higher the C content of reduced iron, the lower the crushing strength of the reduced iron becomes.
  • the reduced iron in the region B is irrelevant to the common general technical knowledge and a high crushing strength is achieved in spite of a high C content.
  • FIG. 6 illustrates the relationship between the porosity of carbon composite briquettes and the crushing strength of reduced iron. As illustrated in FIG. 6 , there is a very strong correlation between the porosity of carbon composite briquettes and the crushing strength of reduced iron regardless of the C content of reduced iron.
  • the porosity of carbon composite briquettes be the predetermined value or less, the distance between iron oxide grains in the carbon composite briquettes becomes short and bonding of metallic iron grains (sintering of metallic iron) after reduction is promoted, which probably results in a further increase in the strength of reduced iron.
  • the lower limit of the porosity is preferably 25%.
  • the porosity of carbon composite briquettes is calculated from the apparent density and true density of carbon composite briquettes:
  • the apparent density of carbon composite briquettes represents the measurement value of the apparent density of dry briquettes; and the true density of carbon composite briquettes represents a weighted average value of true densities of individual materials forming carbon composite briquettes in terms of blending proportions.
  • ironmaking dust As a material, since ironmaking dust has a very small grain size, it may be difficult to compact ironmaking dust.
  • the porosity of carbon composite briquettes be 37.5% or less by standard forming techniques.
  • the following technique may be employed (refer to Japanese Unexamined Patent Application Publication No. 2009-7667): under size after compaction with a briquetting machine is mixed as a recycled material with a new material and returned to the briquetting machine to compact the material to thereby increase the apparent density (that is, decrease the porosity) of carbon composite briquettes.
  • Embodiments 1 and 2 above describe examples in which the grain size of a carbonaceous material contained in the carbon composite briquettes is not particularly limited. By making the grain size of such a carbonaceous material be in a specific range, the crushing strength of a reduced iron product obtained by reducing the carbon composite briquettes is ensured and the amount of carbon remaining in the reduced iron can be further increased.
  • the average grain size d50 of a carbonaceous material in carbon composite briquettes measured by a laser diffraction scattering grain size distribution measurement method is preferably made 30 ⁇ m or less (more preferably, 10 ⁇ m or less).
  • blast-furnace wet dust containing a large amount of carbon grains derived from coke powder or pulverized coal is used as ironmaking dust and the carbon grains of the blast-furnace wet dust are used as a carbonaceous material to prepare carbon composite briquettes.
  • reduced iron obtained by reducing such carbon composite briquettes it has been found that the amount of carbon remaining in the reduced iron can be made high while the crushing strength is ensured.
  • the grain size distribution of the blast-furnace wet dust was measured by a laser diffraction scattering grain size distribution measurement method and the grain size distribution illustrated in FIG. 7 was obtained.
  • FIG. 8 illustrates the blast-furnace wet dust observed with a scanning electron microscope. In FIG.
  • large angular grains are identified as iron oxide; spherical grains are identified as CaO—SiO 2 —FeO slag; as for carbon, which is a light element, carbon grains cannot be identified; however, grains other than the large iron oxide grains are fine grains and hence carbon grains are probably fine grains.
  • the grain size of carbon grains is at least equal to or less than the grain size of the entirety of the blast-furnace wet dust (the average grain size d50 is 30 ⁇ m) in FIG. 7 ; and, from the observation result with a scanning electron microscope in FIG. 8 , the grain size of carbon grains is probably 10 ⁇ m or less in terms of average grain size d50.
  • the average grain size d50 of a carbonaceous material in carbon composite briquettes measured by a laser diffraction scattering grain size distribution measurement method is preferably 30 ⁇ m or less, more preferably 10 ⁇ m or less.
  • the average grain size d50 of a carbonaceous material in carbon composite briquettes may be adjusted, for example, in the following manner.
  • blast-furnace wet dust is used as a portion of materials, the blending proportion of the dust is adjusted.
  • coal powder or coke powder is added as a carbonaceous material, the pulverization grain size of such a powder is adjusted.
  • briquettes are described as an example of the agglomerate form of carbon composite agglomerates.
  • pellets may be employed.
  • a rotary hearth furnace is described.
  • a straight hearth furnace may be employed.
  • the present invention is advantageous as a technique of producing reduced iron from ironmaking dust in ironmaking equipment.

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US13/386,158 2009-07-21 2010-07-21 Carbon composite agglomerate for producing reduced iron and method for producing reduced iron using the same Abandoned US20120240725A1 (en)

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JP2009169719 2009-07-21
JP2009-169719 2009-07-21
PCT/JP2010/062254 WO2011010667A1 (fr) 2009-07-21 2010-07-21 Briquette composite à base de carbone pour la production de fer réduit et procédé pour la production de fer réduit mettant en Œuvre une telle briquette

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EP (1) EP2458020B1 (fr)
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CN (1) CN102471812B (fr)
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TWI711702B (zh) * 2019-09-03 2020-12-01 中國鋼鐵股份有限公司 鐵碳複合材料及鐵氧化物的還原方法

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JP5498919B2 (ja) * 2010-11-15 2014-05-21 株式会社神戸製鋼所 還元鉄の製造方法
RU2493271C1 (ru) * 2012-05-22 2013-09-20 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Волгоградский государственный технический университет" (ВолгГТУ) Брикет для производства чугуна и стали
KR101442920B1 (ko) * 2012-12-18 2014-09-22 주식회사 포스코 환원철 제조방법 및 제조장치
JP6235439B2 (ja) * 2014-09-10 2017-11-22 株式会社神戸製鋼所 粒状金属鉄の製造方法

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