WO1993014862A1 - Treatment of gases discharged from metallurgical furnaces - Google Patents

Treatment of gases discharged from metallurgical furnaces Download PDF

Info

Publication number
WO1993014862A1
WO1993014862A1 PCT/GB1993/000120 GB9300120W WO9314862A1 WO 1993014862 A1 WO1993014862 A1 WO 1993014862A1 GB 9300120 W GB9300120 W GB 9300120W WO 9314862 A1 WO9314862 A1 WO 9314862A1
Authority
WO
WIPO (PCT)
Prior art keywords
lime
coke
furnace
matrix
vessel
Prior art date
Application number
PCT/GB1993/000120
Other languages
French (fr)
Inventor
Robert Walter Mongomery
David Engledow
Original Assignee
British Steel Plc
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 British Steel Plc filed Critical British Steel Plc
Publication of WO1993014862A1 publication Critical patent/WO1993014862A1/en

Links

Classifications

    • 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
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/64—Heavy metals or compounds thereof, e.g. mercury
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/72—Organic compounds not provided for in groups B01D53/48 - B01D53/70, e.g. hydrocarbons
    • 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
    • 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
    • C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
    • C21C5/5217—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace equipped with burners or devices for injecting gas, i.e. oxygen, or pulverulent materials into the furnace
    • 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
    • C21C2005/5282—Charging of the electric furnace with organic contaminated scrap
    • 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 the treatment of gases discharged from metallurgical furnaces (conventionally termed "off-gases") and in particular to the treatment of fume and/or dust laden gases discharged from electric arc furnaces used in the production of steel .
  • gases discharged from electric arc steelmaking furnaces are cooled by dilution with cold air or by water sprays and are then passed through filters or electrostatic precipitators to remove dust present in the gases before being discharged to atmosphere.
  • Filtered off-gas fume and/or dust typically represents approximately 1.5% by weight of the steel
  • ⁇ y ⁇ product of the furnace contains a mixture of metallic oxides. These are principally oxides of iron.
  • the off- gases may also contain valuable metal oxides such as nickel, chromium and molybdenum, and oxides of volatile metals such as zinc, lead, tin, cadmium and mercury.
  • Furnace off-gases may also contain traces of polychlorinated dioxines and dibenzofurans, hereinafter referred to collectively as dioxines, which result from the decomposition of organic contaminants, e.g. oil and certain plastics, in the furnace feedstock.
  • dioxines polychlorinated dioxines and dibenzofurans
  • the present invention provides a method of treating gases discharged from a metallurgical furnace which contain fume and/or dust including metallic oxides and organic contaminants, the method including the step of reacting the gases with a chemical matrix.
  • the metallurgical furnace may be an el.ectric arc steelmaking furnace, and the chemical matrix may be heated by passing an electric current directly through an electrically conducting bed. Alternatively, the heat contained in the off-gases from the furnace may be sufficient in whole or in part to increase the temperature of the chemical matrix to the reaction temperature.
  • the chemical matrix may include coke and the coke may reduce the metallic oxides to metals. Non-volatile metals may be absorbed by the coke and reduced to the metallic state to form a metal impregnated coke mixture.
  • the matrix when heated, may promote decomposition of organic components of the off-gases and the matrix may include lime which may absorb chlorine liberated during the decomposition of organic contaminants.
  • Such coke and lime chemical matrices may be recharged to the steelmaking process.
  • the organic contaminants may include dioxines.
  • apparatus for treating gases discharged from a metallurgical furnace comprising a reaction vessel including an electrically heated bed of a matrix of coke and lime, means for admitting gases to be treated to the vessel for reaction with the coke and lime matrix, means for removing the treated gases from the vessel , and means for removing the coke and lime matrix from the vessel.
  • Dust laden gases from an arc furnace 1 are ducted to a reaction vessel 2 where they are passed through a heated coke and lime matrix 3 before being discharged via a duct 4 to processing plant (not shown) in which volatile metals present in the off-gas are condensed and the residue recovered.
  • the reaction vessel 2 is a refractory lined tower having a hopper 5 through which fresh coke and lime can be charged and pi otably mounted doors 6 through which metal impregnated coke and lime can be discharged into a furnace charging bucket 7.
  • the coke and lime matrix 3 is supported on a grate which may be constructed from refractory covered steel bars 8, which can be withdrawn to allow the reacted coke and lime of the matrix to fall when the doors 6 are opened.
  • the process cycle is linked to the melting cycle of the furnace 1 in that fresh coke and lime are charged to the reactor vessel 2 prior to the commencement of melting a steel charge within the furnace, and the metal impregnated coke and reacted lime are discharged to the furnace charging bucket 7 while the furnace is being tapped.
  • the coke and lime bed may be heated with fossil fuel burners instead of or in addition to the electric current passed via the graphite blocks , and the coke and lime may be placed on a chain grate which may continuously be refreshed at one end and discharged into the melting furnace 1 at the other end.
  • the lime (caO) may initially be charged as limestone (CaC0 3 ) which becomes calcined at the high temperature prevalent in the reaction vessel.
  • the reaction vessel 2 may be installed downstream of an arc furnace scrap pre-heating plant which utilises the furnace off-gas as a source of heat.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Manufacturing & Machinery (AREA)
  • Analytical Chemistry (AREA)
  • Materials Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Furnace Details (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

Fume-laden gases discharged from a metallurgical furnace are treated by being passed through a bed of coke and lime present in a reaction vessel. The bed is preferably heated and may be removed from the vessel for recycling to the furnace.

Description

TREATMENT OF GASES DISCHARGED FROM METALLURGICAL FURNACES
This invention relates to the treatment of gases discharged from metallurgical furnaces (conventionally termed "off-gases") and in particular to the treatment of fume and/or dust laden gases discharged from electric arc furnaces used in the production of steel .
Conventionally, gases discharged from electric arc steelmaking furnaces are cooled by dilution with cold air or by water sprays and are then passed through filters or electrostatic precipitators to remove dust present in the gases before being discharged to atmosphere.
Filtered off-gas fume and/or dust typically represents approximately 1.5% by weight of the steel
~y≠ product of the furnace, and contains a mixture of metallic oxides. These are principally oxides of iron. The off- gases may also contain valuable metal oxides such as nickel, chromium and molybdenum, and oxides of volatile metals such as zinc, lead, tin, cadmium and mercury.
The majority of these oxide wastes are currently dumped in land-fill sites, but this is becoming environmentally unacceptable. Expensive processes are being developed for reducing the dusts in reactor vessels remote from the furnace site, but such processes entail the transport and handling of dust which are notoriously difficult.
Furnace off-gases may also contain traces of polychlorinated dioxines and dibenzofurans, hereinafter referred to collectively as dioxines, which result from the decomposition of organic contaminants, e.g. oil and certain plastics, in the furnace feedstock.
It is an object of this invention to provide a treatment for dust and noxious gases as they leave a metallurgical furnace to enable iron and other metals to be recovered and to reform noxious gases into non-toxic substances for release to the atmosphere. Recovered metals may be returned directly to the steelmaking process.
In one aspect the present invention provides a method of treating gases discharged from a metallurgical furnace which contain fume and/or dust including metallic oxides and organic contaminants, the method including the step of reacting the gases with a chemical matrix.
The metallurgical furnace may be an el.ectric arc steelmaking furnace, and the chemical matrix may be heated by passing an electric current directly through an electrically conducting bed. Alternatively, the heat contained in the off-gases from the furnace may be sufficient in whole or in part to increase the temperature of the chemical matrix to the reaction temperature. The chemical matrix may include coke and the coke may reduce the metallic oxides to metals. Non-volatile metals may be absorbed by the coke and reduced to the metallic state to form a metal impregnated coke mixture.
The matrix, when heated, may promote decomposition of organic components of the off-gases and the matrix may include lime which may absorb chlorine liberated during the decomposition of organic contaminants. Such coke and lime chemical matrices may be recharged to the steelmaking process. The organic contaminants may include dioxines.
In another aspect, there is provided apparatus for treating gases discharged from a metallurgical furnace comprising a reaction vessel including an electrically heated bed of a matrix of coke and lime, means for admitting gases to be treated to the vessel for reaction with the coke and lime matrix, means for removing the treated gases from the vessel , and means for removing the coke and lime matrix from the vessel.
In order that the invention may be fully understood, one embodiment thereof will now be described by way of example only with reference to the accompanying drawing in which the sole Figure is a cross-sectional view of apparatus in accordance with the invention. The Figure shows the general arrangement of plant for processing gases discharged from a metallurgical furnace.
Dust laden gases from an arc furnace 1 are ducted to a reaction vessel 2 where they are passed through a heated coke and lime matrix 3 before being discharged via a duct 4 to processing plant (not shown) in which volatile metals present in the off-gas are condensed and the residue recovered.
The reaction vessel 2 is a refractory lined tower having a hopper 5 through which fresh coke and lime can be charged and pi otably mounted doors 6 through which metal impregnated coke and lime can be discharged into a furnace charging bucket 7.
The coke and lime matrix 3 is supported on a grate which may be constructed from refractory covered steel bars 8, which can be withdrawn to allow the reacted coke and lime of the matrix to fall when the doors 6 are opened.
Electrical connections are made to the coke via expendable graphite blocks 9 or the like set in the sides of the reaction vessel 2, and a high electric current is passed through the coke sufficient to maintain the coke temperature at an optimum value, irrespective of the temperature of the furnace gases under treatment.
The process cycle is linked to the melting cycle of the furnace 1 in that fresh coke and lime are charged to the reactor vessel 2 prior to the commencement of melting a steel charge within the furnace, and the metal impregnated coke and reacted lime are discharged to the furnace charging bucket 7 while the furnace is being tapped.
The coke and lime bed may be heated with fossil fuel burners instead of or in addition to the electric current passed via the graphite blocks , and the coke and lime may be placed on a chain grate which may continuously be refreshed at one end and discharged into the melting furnace 1 at the other end.
The lime (caO) may initially be charged as limestone (CaC03 ) which becomes calcined at the high temperature prevalent in the reaction vessel.
The reaction vessel 2 may be installed downstream of an arc furnace scrap pre-heating plant which utilises the furnace off-gas as a source of heat.
It is to be understood that the foregoing is merely exemplary of the treatment of gases discharged from metallurgical furnaces and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims

CLAIMS :
1. A method of treating gases discharged from a metallurgical furnace which contains fume and/or dust which includes metallic oxides and organic contaminants, the method comprising the step of reacting the gases with a chemical matrix.
2. A method as claimed in Claim 1 wherein the furnace is an electric arc furnace and the chemical matrix is heated by passing an electric current directly through an electrically conducting bed of the matrix.
3. A method as claimed in Claim 1 wherein the furnace is an electric arc furnace and the chemical matrix is heated at least in part by high temperature gases discharged from the furnace.
4. A method as claimed in any one of Claims 1 to 3 wherein the chemical matrix includes coke.
5. A method as claimed in any one of Claims 1 to 3 wherein the chemical matrix includes lime.
6. A method as claimed in Claim 4 wherein the chemical matrix additionally includes lime.
7. Apparatus for treating gases discharged from a metallurgical furnace comprising a reaction vessel including an electrically heated bed of a matrix of coke and lime, means for admitting gases to be treated to the vessel for reaction with the coke and lime matrix, means for removing the treated gases from the vessel , and means for removing the coke and lime matrix from the vessel.
8. Apparatus as claimed in Claim 7 wherein the vessel comprises a refractory lined tower including a hopper through which coke and lime can be charged and gated discharge means through which impregnated coke and lime can be discharged from the vessel .
9. Apparatus as claimed in Claim 7 or Claim 8 further comprising a plurality of refractory coated bars capable of supporting the bed and selectively movable to cause coke and lime of the bed to be discharged from the vessel .
10. Apparatus as claimed in any one of Claims 7 to 9 wherein electrical current for heating the bed is conducted through expendable graphite blocks set in one or more sides of the reaction vessel.
11. A method of treating gases discharged from a metallurgical furnace substantially as herein described and as described with reference to the accompanying diagrammatic drawing.
12. Apparatus for treating gases discharged from a metallurgical furnace substantially as herein described and as described with reference to the accompanying diagrammatic drawing.
PCT/GB1993/000120 1992-01-25 1993-01-20 Treatment of gases discharged from metallurgical furnaces WO1993014862A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9201630A GB9201630D0 (en) 1992-01-25 1992-01-25 Off-gas treatment
GB9201630.2 1992-01-25

Publications (1)

Publication Number Publication Date
WO1993014862A1 true WO1993014862A1 (en) 1993-08-05

Family

ID=10709253

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1993/000120 WO1993014862A1 (en) 1992-01-25 1993-01-20 Treatment of gases discharged from metallurgical furnaces

Country Status (2)

Country Link
GB (1) GB9201630D0 (en)
WO (1) WO1993014862A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006224094A (en) * 2005-01-03 2006-08-31 Air Products & Chemicals Inc Material gas contaminant removal in ion transport membrane system
US7658788B2 (en) 2003-08-06 2010-02-09 Air Products And Chemicals, Inc. Ion transport membrane module and vessel system with directed internal gas flow
US7771519B2 (en) 2005-01-03 2010-08-10 Air Products And Chemicals, Inc. Liners for ion transport membrane systems
US8114193B2 (en) 2003-08-06 2012-02-14 Air Products And Chemicals, Inc. Ion transport membrane module and vessel system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1289685A (en) * 1961-03-29 1962-04-06 Beteiligungs & Patentverw Gmbh Process for the reduction of the risks of explosion, during the eduction of combustible gases
FR1357506A (en) * 1963-05-28 1964-04-03 Centre Nat Rech Metall Process for the recovery of calories from conversion fumes and device for its implementation
EP0479286A1 (en) * 1990-10-05 1992-04-08 Linde Aktiengesellschaft Process for purifying exhaust gas containing dioxines and furanes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1289685A (en) * 1961-03-29 1962-04-06 Beteiligungs & Patentverw Gmbh Process for the reduction of the risks of explosion, during the eduction of combustible gases
FR1357506A (en) * 1963-05-28 1964-04-03 Centre Nat Rech Metall Process for the recovery of calories from conversion fumes and device for its implementation
EP0479286A1 (en) * 1990-10-05 1992-04-08 Linde Aktiengesellschaft Process for purifying exhaust gas containing dioxines and furanes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7658788B2 (en) 2003-08-06 2010-02-09 Air Products And Chemicals, Inc. Ion transport membrane module and vessel system with directed internal gas flow
US8114193B2 (en) 2003-08-06 2012-02-14 Air Products And Chemicals, Inc. Ion transport membrane module and vessel system
JP2006224094A (en) * 2005-01-03 2006-08-31 Air Products & Chemicals Inc Material gas contaminant removal in ion transport membrane system
EP1676624A3 (en) * 2005-01-03 2009-07-29 Air Products and Chemicals, Inc. Feed gas contaminant removal in ion transport membrane systems
US7771519B2 (en) 2005-01-03 2010-08-10 Air Products And Chemicals, Inc. Liners for ion transport membrane systems

Also Published As

Publication number Publication date
GB9201630D0 (en) 1992-03-11

Similar Documents

Publication Publication Date Title
EP1126039B1 (en) Method for reductively processing the liquid slag and the baghouse dust of the electric arc furnace
US7513929B2 (en) Operation of iron oxide recovery furnace for energy savings, volatile metal removal and slag control
US4957551A (en) Method for treatment of dust recovered from off gases in metallurgical processes
RU2086869C1 (en) Method for continuous preliminary heating of charge materials for steel melting furnace and plant for realization of this method
EP0453151B1 (en) Process for recovering valuable metals from a dust containing zinc
CA1239798A (en) Process for recovering valuable metals from an iron dust containing a higher content of zinc
US4673431A (en) Furnace dust recovery process
US5776226A (en) Method for working up refuse or metal-oxide-containing refuse incineration residues
EP0441052A1 (en) Method for recovering zinc from zinc-containing waste materials
EP1165845B1 (en) Method and apparatus for removing undesirable metals from iron-containing materials
US5304230A (en) Method of disposing of organic and inorganic substances and a plant for carrying out the method
US5733356A (en) Method and device for processing free-flowing materials
CN111471866A (en) Method for recycling and harmlessly treating waste aluminum raw material
US6831939B2 (en) Dual use of an induction furnace to produce hot metal or pig iron while processing iron and volatile metal containing materials
KR20000016016A (en) Treatment method for fluidized bed of electric arc furnace dust
US4762554A (en) Process to eliminate hazardous components from the electric arc furnace flue dust and recovering of metals
KR100223515B1 (en) Method and apparatus for preheating and melting scrap
WO1993014862A1 (en) Treatment of gases discharged from metallurgical furnaces
WO2003020989A1 (en) High temperature metal recovery process
AU750943B2 (en) Method for the heat treatment of residues containing heavy metals
US6245123B1 (en) Method of melting oxidic slags and combustion residues
JP2000192159A (en) Continuously detoxicating and resourcing method of aluminum dross and plating sludge with coke-fusion furnace, vertical shaft cupola, blast furnace, fusion furnace and rotary kiln, electric arc furnace, low frequency induction furnace, high frequency induction furnace, or the like
WO2024046656A1 (en) Process for heavy metal removal from iron- and steelmaking flue dust
KR100467801B1 (en) Method and Device for high temperature incineration and thermal decomposition of wastes
Kurka et al. Reducing the content of zinc in metallurgical waste in a rotary kiln

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA GB JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref country code: US

Ref document number: 1993 256692

Date of ref document: 19930925

Kind code of ref document: A

Format of ref document f/p: F

WWE Wipo information: entry into national phase

Ref document number: 1993902419

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1993902419

Country of ref document: EP

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA