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WO2011135485A1 - Procédé et appareil pour préparer du fer à faible teneur en phosphore - Google Patents

Procédé et appareil pour préparer du fer à faible teneur en phosphore Download PDF

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Publication number
WO2011135485A1
WO2011135485A1 PCT/IB2011/051672 IB2011051672W WO2011135485A1 WO 2011135485 A1 WO2011135485 A1 WO 2011135485A1 IB 2011051672 W IB2011051672 W IB 2011051672W WO 2011135485 A1 WO2011135485 A1 WO 2011135485A1
Authority
WO
WIPO (PCT)
Prior art keywords
furnace
charge
bath
slag
iron
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.)
Ceased
Application number
PCT/IB2011/051672
Other languages
English (en)
Inventor
Louis Johannes Fourie
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of WO2011135485A1 publication Critical patent/WO2011135485A1/fr
Anticipated expiration legal-status Critical
Priority to ZA2012/08868A priority Critical patent/ZA201208868B/en
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B11/00—Making pig-iron other than in blast furnaces
    • C21B11/08—Making pig-iron other than in blast furnaces 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
    • C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
    • C21B13/0013—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state introduction of iron oxide into a bath of molten iron containing a carbon reductant
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/02—General features in the manufacture of pig-iron by applying additives, e.g. fluxing agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • 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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/076—Use of slags or fluxes as treating agents
    • 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
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces
    • F27B3/02—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces of single-chamber fixed-hearth type
    • 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
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Electric arc furnaces ; Tank furnaces heated electrically, with or without any other source of heat
    • 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
    • C21C5/54—Processes yielding slags of special composition
    • 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
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies

Definitions

  • This invention relates to a method and apparatus for making iron with a low phosphorous content.
  • Liquid iron is produced from ore and steel plant wastes, but in these processes almost all of the phosphorous in the feed material report to the metal, i.e. the liquid iron, and the slag contains a very low fraction of phosphorous.
  • the partition ratio of phosphorous between slag and iron is determined by thermodynamics, and is generally dependant on factors which include temperature, the carbon content of the iron, the FeO content of the slag and the basicity of the slag.
  • low temperature, high Carbon in the iron, high FeO in the slag and high slag basicity is beneficial to increase the fraction of the phosphorous from the feed material that report to the slag.
  • B is defined as: (%CaO + 0.8x%MgO)/(%SiO 2 +%AI 2 0 3 + 0.8x%P 2 O 5 )
  • liquid bath refers to the liquid contents of the hearth which includes a bath of liquid metal contained by the hearth and a layer of slag floating on top of at least a portion thereof.
  • charge refers to the raw material that is charged into a furnace for processing, and which is still in the solid state, and the word “charging” refers to the act of so feeding raw material into the furnace.
  • burden refers to the total content of a furnace, and includes the liquid iron, the slag, and the charged material.
  • a furnace for producing low phosphorous iron comprising a shell lined with refractory material, the furnace including a hearth, floor, roof, at least one side wall and preferably four side walls, at least one tap hole, at least one feed port for charging the furnace and at least one channel type induction heater located in the floor of the furnace and communicating with the furnace through a throat, with the hearth being configured to operatively contain a bath of liquid metal which is at least partly heated by the induction heater, and the bath having a width of at least 0.8m a depth at least 0.2m, and the length of the furnace being at least 2m, with the feed port configured to charge raw material into the furnace distal from the throat and above the bath of liquid metal such that in combination with the angle of repose of the raw material the raw material covers at least 50% of the upper surface of the bath, and the induction heater being configured to have a power rating of less than about 150 kW/m 2 at the interface between the raw material
  • a method of producing low phosphorous iron which includes the steps of mixing a particulate ore or waste material with an amount of carbon bearing material selected to produce after reduction of iron oxides in the ore or waste material a liquid iron product with a carbon content between about 1 .5% and 4.0%, and flux to produce a furnace charge which operatively generates a slag with a melting point below about 1450 °C and preferably with a basicity of between 0.7 and 1 .3,
  • the method includes additionally heating the charge by combusting reduction gases with preheated air or oxygen or any combination thereof, alternatively introducing and combusting combustion fuel into a combustion chamber formed by the space between the charge and the roof of the furnace, to reduce the charge, and subsequently providing sufficient heat through the induction heater to melt the at least partially reduced iron particles into liquid iron.
  • the method includes analysing the slag composition and to adjust the amount of flux that is mixed into the particulate and carbonaceous material mixture to ensure a slag composition with a melting point below about 1450 °C, and preferably also with a basicity of between 0.7 and 1 .3.
  • Figure 1 is a side perspective view of a liquid metal bath in a furnace according to a first embodiment of the invention, showing the area that the induction heater and a part of the hearth encloses;
  • Figure 2 shows a rear perspective view of a furnace of Figure 1 ;
  • Table 1 shows results from trials conducted in the furnace of Figures 1 and 2.
  • a furnace (1 ) according to a preferred embodiment of the invention is shown in Figures 1 and 2.
  • the furnace (1 ) comprises a shell (2) lined with refractory material (3) to form a combustion chamber (4) and a hearth (5) which contains the liquid metal (6) and slag (7).
  • the furnace (1 ) also includes a roof (22) and walls (8, 9 - the end walls are not shown for the sake of clarity). It also includes a plurality of feed ports (1 0) for feeding, from hoppers (not shown), particulate raw material into the furnace (1 ) to create a charge (1 1 ).
  • the charge (1 1 ) so fed into the furnace (1 ) partly rests on a sloping side wall (8) of the furnace (1 ) and is partly supported by the bath of liquid metal in the form of a bath of molten iron (6) in the hearth (5).
  • the furnace (1 ) includes a channel type induction heater (12) located below the hearth (5). This heater (12) communicates with the liquid bath (6) in the hearth (5) through a throat (not shown).
  • the feed ports (10) are located to one side (14) of the furnace (1 ), and the induction heater (12) is located at the opposing side (15) of the furnace (1 ).
  • the furnace (1 ) also includes a plurality of burners or hot air or oxygen ports (16) in one side wall (9) thereof configured to burn gasses escaping from the charge (1 1 ), or to inject fuel, and one or more of oxygen, hot air, or cold air, through it into the furnace (1 ) for combustion.
  • the furnace (1 ) is fed with a charge (1 1 ).
  • the charge (1 1 ) is created by mixing a particulate ore or waste material with an amount of carbon bearing material selected to achieve after reduction of iron oxides in the ore or waste material a liquid iron product with carbon content between about 1 .5% and 4.0%. Flux is added to the mixture in an amount selected to produce a charge which operatively generates a slag with a melting point below about 1450 °C and basicity between 0.7 and 1 .3.
  • the charge (1 1 ) is fed into the furnace (1 1 ) by means of a plurality of feed ports (10) which are located above a sloping part of the side wall (8) of the furnace (1 ) which extends upwards and away at an angle away from the hearth (5).
  • the feed ports (10) are located above the angled or sloping side wall (8), to operatively charge onto tit.
  • the charge (1 1 ) flows down the sloping side wall (8) to cover a substantial portion, preferably more than 50%, of the upper surface (17) of a liquid metal bath (6) in the furnace (1 ).
  • the charge (1 1 ) is supported by the sloping side wall (8) and a portion is supported by the liquid metal bath (6).
  • the charge (1 1 ) With the charge (1 1 ) being fed into one side (14) of the furnace (1 ) onto the sloping side wall (8), the charge (1 1 ) flows down the sloping side (8) wall onto the liquid metal bath (6).
  • further charging is then done on top of the then existing charge heaps (18) resting on the sloping side wall (8).
  • the induction heater (12) is connected to the furnace (1 ) through the throat (not shown), with this located on the opposite side (15) of the furnace (1 ) with respect to the feed ports (1 0).
  • the charge (1 1 ) is molten from below by the heat from the induction heater (12).
  • the weight of the charge (1 1 ) displaces liquid slag (7) to ensure that a contact surface (1 9) is formed between liquid metal (6) and charge (1 1 ). Since more weight is acting on surface (1 9) farther away from wall (19) towards wall (8) the contact surface (19) is inclined as shown.
  • the drawing indicates a straight line, but in practice the contact surface (19) is curved and the shape is constantly changing as the charge (1 1 ) is melted to join the liquid metal (6) and slag (7) bath, and the charge (1 1 ) subsides under its own weight.
  • the slag (7) Due to the density difference between the slag (7) and the liquid iron (6), the slag (7) will naturally tend to rise up against the slope of the contact surface (19) to collect in the open area (21 ) of the bath above the induction heater (12), being replaced by denser liquid iron (6). This process is continuous with slag (7) being formed the whole time due to the flux that is mixed in with the charge (1 1 ).
  • the charge (1 1 ), at the interface (19) consist of iron and slag forming components that are being melted, a composite metal and slag sintered layer is formed at the interface (1 9).
  • the heat transferred from the induction heater (1 9) to the molten iron (6) is transferred through the thin sintered layer at the interface (19) to the charge through direct contact between these. If the melting temperature of the slag forming components in the sintered layer is high, the metal temperature increases to melt the higher temperature melting slag. It is therefore important to ensure a low melting slag is formed at the interface (19) by adjusting the fluxes mixed in with the feed material to form the charge (1 1 ).
  • the temperature of the metal (6) is therefore controlled by controlling the melting point of the slag (7) and the contact surface area (by adjusting the size of the charge in the furnace), or by adjusting the power input to the inductor(s).
  • the furnace (1 ) is continuously charged from above and the iron particles in the charge (1 1 ) are reduced and melted into the liquid bath. At the same time flux is also included in the charge which creates a liquid slag layer (7) on the liquid iron bath. This continuously increases the volume of material making up the liquid bath, which causes the level of the liquid bath to increase in the hearth (5).
  • the furnace (1 ) is thus continuously or intermittently tapped to remove liquid iron (6) and slag (7) from the hearth (5).
  • the slag (7) is tapped as often as is necessary to maintain the thickness of the slag layer (7) in the open area (21 ) below about 200mm, and preferably below 1 50mm.
  • the slag (7) is tapped from a tap hole or weir located higher in height than a second tap hole for the liquid iron (not shown).
  • the slag weir is maintained open so that slag can flow out continuously or intermittently when there is sufficient slag to maintain flow.
  • the metal weir is also maintained open at all times (unless it has to be closed for maintenance work, for example) for metal to flow out when there is sufficient metal accumulated. The difference in level between the slag weir and metal weir determines the slag thickness.
  • this furnace (1 ) and its method of operation is producing liquid metal, in this instance liquid iron, with a very low amount of phosphorous therein, alternatively the use of high phosphorous content raw materials to produce regular iron.
  • thermodynamics and mechanism which prevents a large proportion of phosphorous that is contained as some compound in the ore to be transferred to the metal is not fully understood and will be the subject of further study.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)

Abstract

L'invention concerne un four (1) pour produire du fer à faible teneur en phosphore qui comprend une carcasse (2) recouverte d'un matériau réfractaire (3), un creuset (5), une sole, une voûte (22), des parois latérales (8), des trous de coulée, des orifices d'alimentation (10) pour la matière première et un appareil chauffant à induction (12) de type conduite situé dans la sole et communiquant avec le creuset par un étranglement. Le creuset (5) contient un bain de métal liquide (6) au moins partiellement chauffé par l'appareil chauffant à induction (12). La charge de la matière première (11) recouvre au moins 50 % du bain (6).
PCT/IB2011/051672 2010-04-26 2011-04-18 Procédé et appareil pour préparer du fer à faible teneur en phosphore Ceased WO2011135485A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
ZA2012/08868A ZA201208868B (en) 2010-04-26 2012-11-23 A method and apparatus for making low phosphorous iron

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA2010/02149 2010-04-26
ZA201002149 2010-04-26

Publications (1)

Publication Number Publication Date
WO2011135485A1 true WO2011135485A1 (fr) 2011-11-03

Family

ID=44860948

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2011/051672 Ceased WO2011135485A1 (fr) 2010-04-26 2011-04-18 Procédé et appareil pour préparer du fer à faible teneur en phosphore

Country Status (2)

Country Link
WO (1) WO2011135485A1 (fr)
ZA (1) ZA201208868B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2024515791A (ja) * 2021-04-28 2024-04-10 ティッセンクルップ スチール ヨーロッパ アーゲー 所望の品質を有するスラグを生産するための方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06158189A (ja) * 1992-11-26 1994-06-07 Hitachi Ltd 金属加熱溶解方法及び溶解装置
JP2001303114A (ja) * 2000-04-27 2001-10-31 Nkk Corp 金属浴型溶融還元炉及び金属製錬設備
JP2007154214A (ja) * 2005-11-30 2007-06-21 Kobe Steel Ltd 超高純度Ｆｅ基、Ｎｉ基、Ｃｏ基合金材料の溶製法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06158189A (ja) * 1992-11-26 1994-06-07 Hitachi Ltd 金属加熱溶解方法及び溶解装置
JP2001303114A (ja) * 2000-04-27 2001-10-31 Nkk Corp 金属浴型溶融還元炉及び金属製錬設備
JP2007154214A (ja) * 2005-11-30 2007-06-21 Kobe Steel Ltd 超高純度Ｆｅ基、Ｎｉ基、Ｃｏ基合金材料の溶製法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2024515791A (ja) * 2021-04-28 2024-04-10 ティッセンクルップ スチール ヨーロッパ アーゲー 所望の品質を有するスラグを生産するための方法

Also Published As

Publication number Publication date
ZA201208868B (en) 2013-09-25

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