US20090051083A1 - Reduction furnace - Google Patents

Reduction furnace Download PDF

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Publication number
US20090051083A1
US20090051083A1 US11/918,921 US91892106A US2009051083A1 US 20090051083 A1 US20090051083 A1 US 20090051083A1 US 91892106 A US91892106 A US 91892106A US 2009051083 A1 US2009051083 A1 US 2009051083A1
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US
United States
Prior art keywords
reduction
reduction furnace
metallic iron
iron
furnace according
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.)
Abandoned
Application number
US11/918,921
Other languages
English (en)
Inventor
Arbeno Vrech
Ilie-Florian Mitoi
Gianfranco Marconi
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.)
Danieli and C Officine Meccaniche SpA
Original Assignee
Danieli and C Officine Meccaniche SpA
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 Danieli and C Officine Meccaniche SpA filed Critical Danieli and C Officine Meccaniche SpA
Assigned to DANIELI & C. OFFICINE MECCANICHE S.P.A. reassignment DANIELI & C. OFFICINE MECCANICHE S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MARCONI, GIANFRANCO, MITOI, ILIE-FLORIAN, VRECH, ARBENO
Publication of US20090051083A1 publication Critical patent/US20090051083A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B19/00—Combinations of different kinds of furnaces that are not all covered by any single one of main groups F27B1/00 - F27B17/00
    • F27B19/04—Combinations of different kinds of furnaces that are not all covered by any single one of main groups F27B1/00 - F27B17/00 arranged for associated working
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B1/00—Shaft or like vertical or substantially vertical furnaces
    • F27B1/10—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B1/21—Arrangements of devices for discharging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0033—Charging; Discharging; Manipulation of charge charging of particulate material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/527—Charging of the electric furnace
    • 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 reduction furnace, in particular a reduction furnace for the production of metallic iron by means of the direct reduction of iron ore, extracted from mines, at a temperature that is less than the melting point of the components.
  • the product obtained as a result of a direct reduction process is known as DRI or “Direct Reduced Iron”.
  • the direct reduction process converts iron ore into highly metallized iron, in the form of lump ore, pellets or a mixture of these components.
  • the process produces reduced iron containing variable quantities of carbon in the form of Fe 3 C.
  • This material is the ideal foodstock for electric arc furnaces used in the production of high-quality steel.
  • Direct reduction systems can thus be made to integrate with systems upstream of electric steelmaking plants.
  • the hot DRI from the furnace or reactor also known as a shaft furnace
  • the hot DRI from the furnace or reactor is usually briquetted or cooled in specific vessels, as it is extremely reactive in air at the temperature at which it leaves the reduction furnace.
  • cooling system is not necessarily always associated with an arc furnace.
  • the cooling vessel can also be used to cool the DRI and render the plant independent of the end use.
  • the presence of a seal leg means the reduction furnace must be placed even higher up if the electric arc furnace (EAF) is gravity-fed.
  • EAF electric arc furnace
  • the main purpose of this invention is to produce a reduction furnace that, by integrating the discharge, transfer and buffer functions in a sloping pipe directly connected to the reduction furnace and the hot off-gases from the process, is capable of reducing heat loss during the passage from the reduction furnace to the electric arc furnace to a minimum, thus reducing electric furnace cycle times, i.e. reducing so-called tap to tap time, and thus reducing energy consumption. Above all this guarantees increased steel plant productivity because a shorter tap to tap time means the same system can be used to produce more castings.
  • the present invention therefore achieves the purposes described above with a reduction furnace, defining a longitudinal axis, for the production of metallic iron by means of the direct reduction of iron ore that, according to claim 1 , comprises an iron ore feed zone, an iron ore reduction zone, and a metallic iron discharge zone, characterised in that it comprises accumulation means communicating at an inlet end with said metallic iron discharge area and at an output end with gas sealing means, said accumulation means being suitable for accumulating said metallic iron together with the off-gases from the reduction process.
  • the diameter and length of the pipe are functions of the volume of the buffer required to separate the reduction and steelmaking plants.
  • the slope of the pipe which must have an angle steeper than the actual DRI repose angle, which is approximately 30°, is such to prevent bridging of the DRI in the pipe.
  • the furnace according to the present invention advantageously reduces the amount of power required by the DRI cooling circuit in the reduction system and eliminates cold DRI handling and management costs.
  • One advantage of the invention is the fact that the hot DRI, produced in the reduction furnace, is sent directly to the steelwork's electric furnace while being maintained at a temperature of approximately 700° C. Furthermore, the system allows the DRI discharge to be controlled and sent simultaneously or alternately through a cooling vessel, so as to obtain cold DRI in a known manner. The portions of DRI to be sent hot to the buffer or to the cooling vessel for cooling, can be metered as required.
  • Another advantage consists of the maximization of the discharge height of the hot DRI, since by integrating the buffer in the reactor, the final discharge point can be placed at the maximum possible height, after the seal leg.
  • the transfer pipe involves the use of one less element compared to the reduction systems known in the prior art, with the elimination of the gas seal leg, and relative inert gas injection device, which connects the reactor to the hot inert vessel.
  • FIG. 1 is a front view of a system comprising the furnace according to the present invention
  • FIG. 2 is a cross-section of a part of the furnace in FIG. 1 ;
  • FIG. 3 is a cross-section, on a plane orthogonal to that in FIG. 1 , of a detail of the furnace according to the invention
  • FIGS. 4 and 5 are cross-sections of the detail in FIG. 3 on the same plane as FIG. 1 .
  • Said reduction shaft comprises:
  • the furnace or reactor 1 produces hot DRI, starting from oxides in the form of pellets and/or lumps, which it discharges at a high temperature through a zone, preferably a conically-shaped zone, into the transfer pipe 6 .
  • Said transfer pipe 6 through regulating means 3 that control the hot discharge from the reactor 1 , enables portions of DRI to be directed simultaneously or alternately to an electric arc furnace and to the cooling vessel 5 , and also acts as an accumulator, also referred to as a “buffer” in this description.
  • a collecting duct 4 inserted into the pipe 6 and having a diameter larger than the base of the cone of the reactor 1 , is directly connected to the cooling vessel 5 and material passes through said duct at all times when the system is running. In the area 2 of the transfer pipe 6 a pile of material builds up according to the natural repose angle thereof.
  • the cooling vessel 5 is in turn directly connected to a cold discharge device 10 via a dynamic gas seal leg 9 .
  • a cold discharge device 10 via a dynamic gas seal leg 9 .
  • the activation of the discharge device 10 generates a flow of material along the entire height of the reduction shaft, while the repose angles in the area 2 remain unchanged.
  • the area 2 thus becomes an open point at which it is possible and easy to pick up portions of hot DRI which can be diverted, discharged or forced out of the collecting duct 4 and thus towards the pipe or buffer 6 .
  • the hot discharge regulating means may comprise, for instance, a blade 3 arranged transversely in relation to the flow of material from the reactor 1 , controlled by a hydraulic cylinder. This blade 3 sweeps the pile of material in the area 2 with an oscillating movement, so that portions of hot DRI can be discharged outside the duct 4 towards the transfer pipe 6 and, at the same time, inside the duct 4 towards the cooling vessel 5 .
  • the speed at which the blade 3 oscillates determines the control of the input flow both to the cooling vessel 5 and to the transfer pipe 6 .
  • the blade 3 When in the home position the blade 3 is parked outside the pile of DRI and does not obstruct the flow towards the cooling vessel 5 .
  • the blade 3 may be operated autonomously, or it may advantageously be joined to a “flow promoter” 8 the function of which is to prevent bridging in the end part of the discharge cone 1 ′ of the cone of the reactor 1 .
  • This basically consists of through pipes with wear-proof protuberances that rotate by a few degrees about their own axis alternately in the two directions at very low frequency. This movement prevents bridging in the discharge cone 1 ′ and guarantees a good material flow.
  • the flow promoters 8 are not metering systems. The alternating movement of these elements can be likened in terms of frequency to that of the blade 3 .
  • the blade 3 can therefore advantageously be operated by appropriately connecting it to the actual axis H of the flow promoter 8 .
  • the blade 3 regulates the amount of material that is discharged, while the flow promoter 8 promotes a correct and full supply.
  • the blade 3 is autonomous or fixed to the axis of the flow promoter 8 , in the home position it is always parked outside the pile of DRI that builds up in the area 2 in the upper part of the transfer pipe 6 , and does not obstruct the flow of DRI towards the cooling vessel 5 .
  • FIGS. 3 , 4 and 5 An advantageous alternative form of the regulating means, which allows the flow promoter 8 to remain active both when the blade 3 is in the home position and when acting as a meter, is illustrated in FIGS. 3 , 4 and 5 .
  • the blade 3 In the home position the blade 3 continues to oscillate in an empty environment.
  • there are two actuators 11 , 12 for instance hydraulic actuators, that drive two levers 13 , 14 that are integral with the axis H of the flow promoter.
  • the blade 3 at work or in the home position only one of the two hydraulic actuators 11 , 12 is operational, while the hydraulic circuit of the other is short-circuited so as not to offer mechanical resistance.
  • the reactor 1 can thus be discharged, simultaneously diverting a portion of the material to the transfer pipe 6 and a portion to the cooling vessel 5 , depending on the way in which the devices 3 and 10 are activated and controlled.
  • the hot DRI that collects inside the transfer pipe 6 set at a slope and with an internal coating of refractory material, passes through the actual pipe together with the hot off-gases from the process.
  • the pipe 6 thus simultaneously performs the following functions:
  • the presence of the off-gases from the process in the transfer pipe 6 advantageously eliminates the problem of DRI re-oxidation and also promotes heat retention.
  • the hot DRI that accumulates in the transfer pipe 6 is discharged towards the user, at fixed intervals of time, via a dynamic seal leg 7 , which has the function of maintaining the off-gases from the process inside the pipe 6 .
  • the pipe/buffer is not thus inert.
  • a second flow regulating device for instance a vibro-extractor, rotary valve, oscillating blade or the like.
  • the hot DRI may be transported directly by gravity to the electric arc furnace, if the systems are arranged very close together, or transferred to the electric arc furnace by means of an inert conveyor system.
  • the diameter and length of the transfer pipe 6 must be appropriately defined as a function of the volume of the buffer that is needed in order to separate the reduction furnace and the steelmaking plant.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Geology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacture Of Iron (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Furnace Details (AREA)
US11/918,921 2005-04-22 2006-04-21 Reduction furnace Abandoned US20090051083A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
ITMI2005A000731 2005-04-22
IT000731A ITMI20050731A1 (it) 2005-04-22 2005-04-22 Forno di riduzione
PCT/EP2006/061738 WO2006111574A1 (en) 2005-04-22 2006-04-21 Reduction furnace

Publications (1)

Publication Number Publication Date
US20090051083A1 true US20090051083A1 (en) 2009-02-26

Family

ID=35670980

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/918,921 Abandoned US20090051083A1 (en) 2005-04-22 2006-04-21 Reduction furnace

Country Status (9)

Country Link
US (1) US20090051083A1 (pt)
EP (1) EP1877714B1 (pt)
AT (1) ATE458974T1 (pt)
BR (1) BRPI0607534B1 (pt)
DE (1) DE602006012474D1 (pt)
EG (1) EG25071A (pt)
IT (1) ITMI20050731A1 (pt)
MX (1) MX2007013114A (pt)
WO (1) WO2006111574A1 (pt)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102168185A (zh) * 2011-03-20 2011-08-31 梁小军 立式还原炉
US8518146B2 (en) 2009-06-29 2013-08-27 Gb Group Holdings Limited Metal reduction processes, metallurgical processes and products and apparatus
US20130276584A1 (en) * 2010-11-03 2013-10-24 Technological Resources Pty. Limited Production of iron
WO2020171079A1 (ja) * 2019-02-19 2020-08-27 合同会社Ｋｅｓｓ 直接還元鉄製造設備
US20210301359A1 (en) * 2020-03-24 2021-09-30 Midrex Technologies, Inc. Integration of dr plant and electric dri melting furnace for producing high performance iron
CN114921603A (zh) * 2022-05-31 2022-08-19 中冶京诚工程技术有限公司 螺旋式热态直接还原铁输送装置及方法
CN116516093A (zh) * 2023-05-22 2023-08-01 河钢集团有限公司 一种直接还原铁的生产装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006062689B4 (de) * 2006-12-21 2009-01-22 Mines And Metals Engineering Gmbh (M.M.E.) Schachtofen für die direkte Reduktion von Eisenoxid
AT509357B1 (de) * 2010-01-15 2012-01-15 Siemens Vai Metals Tech Gmbh Verfahren und vorrichtung zur reduktion von eisenerzhältigen einsatzstoffen oder zur herstellung von roheisen oder flüssigen stahlvorprodukten

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4256290A (en) * 1979-10-15 1981-03-17 Pullman Incorporated Bottom cooling arrangement for reduction apparatus
US4270739A (en) * 1979-10-22 1981-06-02 Midrex Corporation Apparatus for direct reduction of iron using high sulfur gas
US4729786A (en) * 1984-08-16 1988-03-08 Voest-Alpine Aktiengesellschaft Process for the direct reduction of iron-oxide-containing materials
US5676732A (en) * 1995-09-15 1997-10-14 Hylsa, S.A. De C.V. Method for producing direct reduced iron utilizing a reducing gas with a high content of carbon monoxide
US6200363B1 (en) * 1998-10-09 2001-03-13 Midrex International B.V. Rotterdam Zurich Branch Direct reduced iron hot/cold discharge system
US6214086B1 (en) * 1999-08-20 2001-04-10 Midrex International B.V. Rotterdam, Zurich Branch Direct reduced iron discharge system and method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4256290A (en) * 1979-10-15 1981-03-17 Pullman Incorporated Bottom cooling arrangement for reduction apparatus
US4270739A (en) * 1979-10-22 1981-06-02 Midrex Corporation Apparatus for direct reduction of iron using high sulfur gas
US4729786A (en) * 1984-08-16 1988-03-08 Voest-Alpine Aktiengesellschaft Process for the direct reduction of iron-oxide-containing materials
US5676732A (en) * 1995-09-15 1997-10-14 Hylsa, S.A. De C.V. Method for producing direct reduced iron utilizing a reducing gas with a high content of carbon monoxide
US6200363B1 (en) * 1998-10-09 2001-03-13 Midrex International B.V. Rotterdam Zurich Branch Direct reduced iron hot/cold discharge system
US6214086B1 (en) * 1999-08-20 2001-04-10 Midrex International B.V. Rotterdam, Zurich Branch Direct reduced iron discharge system and method

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8518146B2 (en) 2009-06-29 2013-08-27 Gb Group Holdings Limited Metal reduction processes, metallurgical processes and products and apparatus
US20130276584A1 (en) * 2010-11-03 2013-10-24 Technological Resources Pty. Limited Production of iron
US9376730B2 (en) * 2010-11-03 2016-06-28 Technological Resources Pty. Limited Production of iron
CN102168185A (zh) * 2011-03-20 2011-08-31 梁小军 立式还原炉
WO2020171079A1 (ja) * 2019-02-19 2020-08-27 合同会社Ｋｅｓｓ 直接還元鉄製造設備
US20210301359A1 (en) * 2020-03-24 2021-09-30 Midrex Technologies, Inc. Integration of dr plant and electric dri melting furnace for producing high performance iron
US11788159B2 (en) * 2020-03-24 2023-10-17 Midrex Technologies, Inc. Integration of DR plant and electric DRI melting furnace for producing high performance iron
CN114921603A (zh) * 2022-05-31 2022-08-19 中冶京诚工程技术有限公司 螺旋式热态直接还原铁输送装置及方法
CN116516093A (zh) * 2023-05-22 2023-08-01 河钢集团有限公司 一种直接还原铁的生产装置

Also Published As

Publication number Publication date
ITMI20050731A1 (it) 2006-10-23
EG25071A (en) 2011-07-28
BRPI0607534B1 (pt) 2015-06-30
BRPI0607534A2 (pt) 2009-09-15
WO2006111574A1 (en) 2006-10-26
MX2007013114A (es) 2008-01-11
ATE458974T1 (de) 2010-03-15
EP1877714A1 (en) 2008-01-16
EP1877714B1 (en) 2010-02-24
DE602006012474D1 (de) 2010-04-08

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Legal Events

Date Code Title Description
AS Assignment

Owner name: DANIELI & C. OFFICINE MECCANICHE S.P.A., ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:VRECH, ARBENO;MITOI, ILIE-FLORIAN;MARCONI, GIANFRANCO;REEL/FRAME:020043/0731

Effective date: 20060526

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION