WO2000039351A1 - Traitement de la poussiere de four electrique a arc par bouletage et reduction par lit fluidise - Google Patents

Traitement de la poussiere de four electrique a arc par bouletage et reduction par lit fluidise Download PDF

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Publication number
WO2000039351A1
WO2000039351A1 PCT/IB1999/002036 IB9902036W WO0039351A1 WO 2000039351 A1 WO2000039351 A1 WO 2000039351A1 IB 9902036 W IB9902036 W IB 9902036W WO 0039351 A1 WO0039351 A1 WO 0039351A1
Authority
WO
WIPO (PCT)
Prior art keywords
eaf dust
pellets
eaf
treatment process
dust
Prior art date
Application number
PCT/IB1999/002036
Other languages
English (en)
Inventor
Peter William Ennis Blom
Original Assignee
L & C Steinmuller (Africa) (Proprietary) Limited
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 L & C Steinmuller (Africa) (Proprietary) Limited filed Critical L & C Steinmuller (Africa) (Proprietary) Limited
Priority to AU16747/00A priority Critical patent/AU1674700A/en
Publication of WO2000039351A1 publication Critical patent/WO2000039351A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0033—In fluidised bed furnaces or apparatus containing a dispersion of the material
    • 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
    • C22B1/2413—Binding; Briquetting ; Granulating enduration of pellets
    • 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
    • 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
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
    • 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

  • THIS invention relates to the treatment of electric arc furnace (EAF) dust.
  • EAF electric arc furnace
  • WO 97/45564 (PCT/GB97/01445) describes a method of treating EAF dust in which preheated and decontaminated EAF dust is introduced into a fiuidised bed reactor in which hematite is reduced by means of a hot reducing gas generated by reforming natural gas in a non-catalytic plasma- arc heating process to produce an iron-rich material suitable for recycling to the electric arc furnace.
  • EAF dust is in very fine particulate form. In practice some 20% or more of the EAF dust may have a particle size less than 0,5 x 10 "6 m. This can lead to problems in the fiuidised bed reduction reactor where the fine dust particles can cause blockages in the filter candles in the reactor, leading in turn to an increase in the pressure drop across the reactor. In addition, fine dust which is carried over in the exit gas stream can contaminate the zinc oxide fume product of the treatment process.
  • an EAF dust treatment process wherein preheated and decontaminated EAF dust is introduced into a fiuidised bed reactor in which hematite is reduced by means of a hot reducing gas generated by reforming natural gas in a non-catalytic plasma-arc heating process to produce an iron-rich material suitable for recycling to the electric arc furnace, characterised in that the EAF dust is pelletised prior to introduction into the fiuidised bed reactor.
  • a binder may also fed into the pelletiser for mixture with the EAF dust and water.
  • a method of pelletising EAF dust which comprises feeding predetermined quantities of EAF dust and water into a pelletizer which mixes the dust and water and forms the mixture into pellets, feeding pellets which are produced by the pelletiser into a drying kiln where they are dried at a first elevated temperature and feeding the dried pellets into a curing kiln where they are cured at a second, substantially higher temperature.
  • Figure 1 is a flow diagram illustrating the pelletisation and curing of EAF dust in accordance with the invention.
  • Figure 2 shows a flow diagram of an EAF dust treatment process.
  • Figure 1 illustrates the micro-pelletisation, drying and curing of EAF dust which will subsequently be fed to the fluidised bed reduction reactor in the EAF dust treatment process described in WO 97/45564, to which reference should be made for the details of that process.
  • blended EAF dust 10 produced by an electric arc furnace is fed from a dust surge bin into a dust scale vessel 12 by means of a screw conveyor 14.
  • pelletising water 16 is fed into a water scale vessel 18 and a suitable binder 20 is fed into a binder scale vessel 22.
  • the EAF dust, water and binder are then fed from the scale vessels 12, 18 and 22 to a pelletiser 24 in predetermined quantities.
  • the pelletiser 24 is a high intensity mixer consisting of a rotary drum and an agitator driven by separate motors.
  • the drum and agitator rotate in opposite directions. Their rotation is continuous, even during charging and
  • SUBSTITUTE SHEET (RULE 26 ⁇ discharging operations, and their rotary speeds are independently adjustable to achieve appropriate control over the size of the pellets which are produced.
  • the pellets produced by the pelletiser are discharged through hydraulically operated doors 26 onto a variable speed green pellet conveyor 28.
  • the belt is driven fast to spread the pellets evenly over its length.
  • the conveyor is switched to a slower speed to ensure a continuous feed of pellets to the pellet dryer furnace or drying kiln 30. It will accordingly be understood that while the pelletising steps described above are carried out batchwise, the feed to the drying kiln 30 is continuous.
  • a chute 32 feeds the green EAF dust pellets to the inlet of the drying kiln 30 at a constant rate.
  • the EAF dust pellets will typically contain approximately 12% water by weight.
  • the entire water content is evaporated and the pellets are heated to a temperature in the range 120°C and 150°C. Heat is supplied to the drying kiln by the burner offgas from the curing kiln described below.
  • the temperature of the incoming gas 34 is constantly controlled by a thermocouple control system to a value of 600°C maximum. If required, a control damper 36 adds dilution air before the hot offgas reaches the kiln 30.
  • the burner will be fired automatically under control of the thermocouple control system on detection of the low temperature condition.
  • the dried EAF dust pellets exit the drying kiln, at a temperature in the range 120°C to 150°C, onto a screen 38 with a ⁇ 2mm cut.
  • the oversize material flows to a roller crusher 40 which reduces its size to an acceptable value, whereafter it rejoins the undersize material to be fed through a chute 42 to a curing furnace or kiln 44.
  • the curing kiln 44 is heated indirectly by burners located in the sidewalls of the combustion chamber.
  • the burners are controlled at a selectable, preprogrammed temperature setpoint by thermocouples located in the roof of the combustion chamber.
  • the EAF dust pellets are maintained at a temperature of about 950 °C for about 30 minutes in the curing kiln to obtain a sufficiently strong bond between the EAF dust and the binder.
  • Process gas 46 enters the upstream end of the curing kiln and is extracted with offgas 48 at the downstream end.
  • Cured EAF dust pellets drop out of the curing kiln 44, into a hot drop-out box (not shown) though a slot in the circumference of the kiln tube and are transferred from the hot drop-out box for processing as indicated by the line 50.
  • both the drying and curing kilns have variable speed drives to enable their rotation to be slowed down when maintenance on downstream processing equipment has to be carried out.
  • the pelletising process and subsequent drying and curing are carried out so as to produce micro-pellets of EAF dust which preferably have a size in the range 0,5mm to 2mm.
  • the process produces hard micro-pellets which will suffer minimum abrasive degradation when they are subsequently subjected to fluidise bed processing.
  • pellets formed without a binder as well as pellets formed with a Peridure binder and a Bentonite binder were tested. The results showed that, on induration in the curing kiln, the binderless pellets decreased quite substantially in size while Peridure bonded pellets also showed a size decrease but not to the same extent. The Bentonite bonded pellets showed little change.
  • Figure 1 (A and B) also shows the pre- pelletising and curing steps, described above, which are carried out initially. It will be appreciated that both induration of the dust pellets and oxidation of the dust is carried out in the curing kiln 44, and that the remaining steps in the EAF dust treatment method described in WO 97/45564 are unchanged.
  • the curing kiln may be a rotary hearth or chain grate furnace.
  • SUBST ⁇ TUTE SHEET (RULE ) that there will be only a small percentage of fines in the fluidised bed reduction reactor which will make it possible to operate the system without an internal metallic filter system which is prone to blockage when substantial quantities of fines are present.
  • the fluidised bed reduction reactor produces minimal fines the zinc oxide fume, which is a valuable product of the process, will be less prone to undesirable contamination.
  • the process will produce direct reduced iron in micro-pellet as opposed to powder form. The micro-pellet form which is produced is considered to be a superior product.

Landscapes

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

Abstract

L'invention concerne un procédé de traitement de la poussière de four à arc électrique. Dans ce procédé, on introduit la poussière de four à arc électrique préchauffée et décontaminée dans un réacteur à lit fluidisé où l'hématite est réduite au moyen d'un gaz de réduction chaud généré par le gaz naturel de conversion selon un processus non catalytique de chauffage au plasma, afin de produire un matériau riche en fer approprié au recyclage dans le four à arc électrique. L'invention est caractérisée en ce que la poussière de four à arc électrique est bouletée avant d'être introduite dans le réacteur à lit fluidisé.
PCT/IB1999/002036 1998-12-23 1999-12-22 Traitement de la poussiere de four electrique a arc par bouletage et reduction par lit fluidise WO2000039351A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU16747/00A AU1674700A (en) 1998-12-23 1999-12-22 Eaf dust treatment by pelletising and fluidised-bed reduction

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA9811853 1998-12-23
ZA98/11853 1998-12-23

Publications (1)

Publication Number Publication Date
WO2000039351A1 true WO2000039351A1 (fr) 2000-07-06

Family

ID=25587476

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1999/002036 WO2000039351A1 (fr) 1998-12-23 1999-12-22 Traitement de la poussiere de four electrique a arc par bouletage et reduction par lit fluidise

Country Status (2)

Country Link
AU (1) AU1674700A (fr)
WO (1) WO2000039351A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1165845A2 (fr) * 1999-02-25 2002-01-02 HYLSA, S.A. de C.V. Procede et appareil d'elimination de metaux indesirables sur des matieres contenant du fer
CN104232888A (zh) * 2013-06-21 2014-12-24 上海梅山钢铁股份有限公司 一种用转炉煤气干法电除尘灰制造冷固球团的方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831913A (en) * 1971-08-12 1974-08-27 Nippon Kokan Kk Apparatus for direct iron reduction
US3945817A (en) * 1973-12-17 1976-03-23 Nippon Kokan Kabushiki Kaisha Method for the collection of dust of a high zinc content during the production of reduced iron pellets
US4043831A (en) * 1975-07-07 1977-08-23 Cogas Development Co. Densification of coal fly ash
JPS5432115A (en) * 1977-08-16 1979-03-09 Sumitomo Heavy Ind Ltd Manufacture of iron-containing pellets
WO1982001724A1 (fr) * 1980-11-10 1982-05-27 John O Edstroem Procede permettant d'obtenir du metal a partir d'un materiau d'oxyde metallique finement granule
EP0118149A1 (fr) * 1983-02-25 1984-09-12 Metallgesellschaft Ag Procédé de durcissement par cuisson de pellets verts dans une machine à cuire les pellets
WO1997018338A1 (fr) * 1995-11-14 1997-05-22 Arc Dust Processing (Uk) Limited Procede de traitement de materiau en fines particules incorporant des constituants a base de metal
WO1997045564A1 (fr) * 1996-05-28 1997-12-04 L & C Steinmuller (Africa) (Proprietary) Limited Traitement en lit fluidise de la poussiere de four electrique a arc

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831913A (en) * 1971-08-12 1974-08-27 Nippon Kokan Kk Apparatus for direct iron reduction
US3945817A (en) * 1973-12-17 1976-03-23 Nippon Kokan Kabushiki Kaisha Method for the collection of dust of a high zinc content during the production of reduced iron pellets
US4043831A (en) * 1975-07-07 1977-08-23 Cogas Development Co. Densification of coal fly ash
JPS5432115A (en) * 1977-08-16 1979-03-09 Sumitomo Heavy Ind Ltd Manufacture of iron-containing pellets
WO1982001724A1 (fr) * 1980-11-10 1982-05-27 John O Edstroem Procede permettant d'obtenir du metal a partir d'un materiau d'oxyde metallique finement granule
EP0118149A1 (fr) * 1983-02-25 1984-09-12 Metallgesellschaft Ag Procédé de durcissement par cuisson de pellets verts dans une machine à cuire les pellets
WO1997018338A1 (fr) * 1995-11-14 1997-05-22 Arc Dust Processing (Uk) Limited Procede de traitement de materiau en fines particules incorporant des constituants a base de metal
WO1997045564A1 (fr) * 1996-05-28 1997-12-04 L & C Steinmuller (Africa) (Proprietary) Limited Traitement en lit fluidise de la poussiere de four electrique a arc

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Derwent World Patents Index; Class A18, AN 1973-15600U, XP002135039 *
DATABASE WPI Section Ch Week 197916, Derwent World Patents Index; Class M24, AN 1979-30468B, XP002135040 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1165845A2 (fr) * 1999-02-25 2002-01-02 HYLSA, S.A. de C.V. Procede et appareil d'elimination de metaux indesirables sur des matieres contenant du fer
EP1165845A4 (fr) * 1999-02-25 2002-06-12 Hylsa Sa Procede et appareil d'elimination de metaux indesirables sur des matieres contenant du fer
CN104232888A (zh) * 2013-06-21 2014-12-24 上海梅山钢铁股份有限公司 一种用转炉煤气干法电除尘灰制造冷固球团的方法

Also Published As

Publication number Publication date
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