EP1794333A2 - Procede utilisant une reduction carbothermique en four unique avec regulation de la temperature a l'interieur du four - Google Patents

Procede utilisant une reduction carbothermique en four unique avec regulation de la temperature a l'interieur du four

Info

Publication number
EP1794333A2
EP1794333A2 EP05794450A EP05794450A EP1794333A2 EP 1794333 A2 EP1794333 A2 EP 1794333A2 EP 05794450 A EP05794450 A EP 05794450A EP 05794450 A EP05794450 A EP 05794450A EP 1794333 A2 EP1794333 A2 EP 1794333A2
Authority
EP
European Patent Office
Prior art keywords
slag
furnace
phase
temperature
reactor
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.)
Withdrawn
Application number
EP05794450A
Other languages
German (de)
English (en)
Inventor
Richard J. Fruehan
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.)
Elkem ASA
Howmet Aerospace Inc
Original Assignee
Elkem ASA
Alcoa Inc
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 Elkem ASA, Alcoa Inc filed Critical Elkem ASA
Publication of EP1794333A2 publication Critical patent/EP1794333A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
    • C22B4/02—Light metals
    • 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
    • C22B21/00—Obtaining aluminium
    • C22B21/02—Obtaining aluminium with reducing
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents

Definitions

  • the present invention relates to a method of producing low carbon aluminum in a single reactor compartment carbothermic furnace with control to lower or raise the temperature of reactants within the interior of the reactor compartment.
  • Al 2 O 3 + 2C Al 2 O (vapor) + 2CO (vapor) (4)
  • Kibby '757 patent uses arc heating and a plasma jet in a process that starts at 1850°C-1950°C, then arc heats to 2100°C, producing Al with ⁇ 10 wt.% C.
  • the latter Kibby '107 utilizes a secondary furnace or separate decarbonization zone requiring transfer of very hot metal and slag to and from the furnace.
  • This slag is then used to begin the next cycle.
  • the next cycle is begun by adding some C and Al 2 O 3 to the bottom slag and repeating steps (c) to (e).
  • the tapped aluminum phase is Al ⁇ 3 wt% C and the Al 4 C 3 added in step (c) is from a vapor recovery unit associated with the reactor.
  • Fig. 1 is a flow sheet showing one example of a previously conceptualized system of a carbothermic reduction process for the production of aluminum, including an off- gas vapor recovery reactor to recover the Al 2 O and Al vapors as Al 4 C 3 and/or Al 2 O 3 solids (and Al 4 C 3 -Al 2 O 3 slag); and
  • FIG. 2 is flow sheet showing the steps involved in this invention to produce low carbon aluminum utilizing a single reactor.
  • the off-gas from a carbothermic smelting furnace here, for simplicity, comprising a first stage 1 and possibly a second stage 2 is forwarded via conduits 3 and 4 to an enclosed off-gas reactor 5 operating at a temperature of about 1600°C to 2050°C depending on the type reactor.
  • the reactor 5 could be a counter-current moving bed reactor or a fluid bed or a series of fluid beds.
  • the Al- components of the off-gas entering the reactor 5 react with the carbon to form Al 4 C 3 , Al 2 O 3 and Al 4 C 3 -Al 2 O 3 slag material.
  • Conduit 6 can be used to pass this material to stage 2.
  • the gas from reactor 5 contains primarily CO, and possibly some H 2 from the volatile part of the charcoal reactor charge and little or no Al or Al 2 O.
  • the off gas from reactor 5 has a high energy value as hot CO and could be used to produce electrical energy in a gas turbine or conventional boiler.
  • the aluminum vapor species will have reacted to carbide, condensed to Al 2 O 3 and C or formed an Al 2 O 3 -Al 4 C 3 slag.
  • the Al 4 C 3 -Al 2 O 3 slag and unreacted carbon is fed into the second stage of the carbothermic smelter via conduit 6.
  • An Al-C liquid alloy exits smelter stage 2 as shown in Fig. 1, where (s) means solid, (v) means vapor and (liq) means liquid in Fig. 1.
  • Fig. 2 illustrates the basic steps, reactions and reactants in the method of this invention.
  • This new process uses a single furnace, so no slag recycle is required, and slag resistance heating to avoid excess vaporization.
  • Al 2 O 3 and carbon are added and Al 2 O 3 -Al 4 C 3 slag is produced which can contain excess Al 4 C 3 above saturation.
  • the furnace operates at about 1875°C to 2000°C to produce slag.
  • the second step produces an Al-6-8 wt% C alloy at about 2050 0 C to 2100 0 C and requires additional energy and additional Al 4 C 3 , part of which is the excess from the first step and the remainder is from the vapor recovery unit.
  • slag is produced in the first step 10 of Fig. 2, slag is produced.
  • metal 21 is produced with about 5 to 7wt% C on top of a slag phase 22 and gases are released (not shown for the sake of simplicity).
  • an extraction or decarbonization reaction is provided, at lowered temperatures to reduce vapor loss, where added Al 2 O 3 , is at ambient temperature (about 20 0 C to about 35°C), and importantly, helps lower both temperature substantially and provides an alumina rich slag in step 40.
  • C is transferred from the Al phase to provide an aluminum phase containing less than ( ⁇ ) 5 wt% C phase, preferably a ⁇ 3 wt% C phase 23, which is then tapped. Steps 30 and 40 merge somewhat.
  • Aluminum carbide is added from the vapor recovery reactor 5. About 17% of the Al will vaporize as Al 2 O and Al. It is not possible to react all of the slag since the energy is supplied by slag resistance heating through the slag and some slag must remain in the furnace. About 20% of the slag does not react and remains for resistance heating. Some decarburization can occur by raising the temperature after all the carbide is added and reducing the carbide content of the slag and carbon in the metal but this will result in large amounts OfAl 2 O and Al vaporization.
  • Decarburization Al 2 O 3 is added to the furnace to remove carbon from the metal. Some electric power is necessary to heat and melt the Al 2 O 3 while some of the energy comes from the sensible heat of the slag since its temperature is higher than required for decarburization.
  • the slag-metal system is allowed to cool to about 1850 0 C.
  • the slag becomes rich in Al 2 O 3 and carbon is transferred from the metal to the slag (Al 4 C 3 ).
  • the metal is tapped and the resulting Al 2 O 3 rich liquid slag is the starting point for return to slag making.
  • the temperature is increased to about 1900°C-2000°C and Al 2 O 3 and carbon are added once more, to produce the desired liquid slag composition and excess Al 4 C 3 for metal making.
  • substantial amounts of CO are produced which carry Al as Al and Al 2 O gaseous species. These are converted to Al 4 C 3 in the vapor recovery reactor 5 and returned to the furnace during metal making, all as shown in Fig. 2.
  • a single furnace 11 having side walls and a bottom, and a single, hollow reactor compartment 13, as shown in Fig. 2, is used solely in this invention; without interior underflow partition walls/baffles or the like.
  • the furnace can have a substantially rectangular, square, circular or oval shape.
  • bottom resistance heating electrodes 16 preferably located in the side(s) of the reactor as shown.
  • at least one top vertical retractable exterior electrode 12 is used. It can provide an arc to melt the solid Al 2 O 3 and C at start-up or at steady state, added to producing molten slag phase Al 2 O 3 - Al 4 C 3 slag plus additional Al 4 C 3 .
  • the electrodes 12 and 16 can be made from carbon, graphite, or non- consumable inert ceramic materials, where each is individually supplied with electricity by electric current means 19.
  • the bottom resistance heating electrodes are preferably horizontal and used in metal making to reduce super heating the metal and causing excessive vaporization.
  • the bottom electrodes 16 are also preferably disposed at/adjacent to the bottom phase molten slag phase/level 22, as shown in steps 20, 30 and 40.
  • Al 2 O, vapor, CO and Al exit as streams 3 and 3'.
  • the Al 2 O 3 , C, Al 4 C 3 supply means in steps 10 to 30 are preferably gas tight.
  • the Al vaporized will produce about 15 moles of carbide. During slag making enough Al is vaporized to produce 10 moles of carbide. A total of 62 moles of carbide are required in the metal making step. With 28 moles of carbide reacting from the slag and about 25 moles from the vapor recovery reactor ("VRR") there is a deficit of about 9 moles of Al 4 C 3 . This additional carbide can be produced in slag making so the actual starting point is:
  • the slag + Al 4 C 3 is heated to a higher temperature (2050°C- 2100°C) producing 310 k moles aluminum metal containing about 7.5 wt.% C. About 20 k moles of slag remain for resistance heating.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Furnace Details (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Glass Melting And Manufacturing (AREA)

Abstract

Un procédé de démarrage de la fabrication d'aluminium au moyen d'un four/réacteur carbothermique unique (11) présentant un compartiment à réacteur creux unique avec des électrodes inférieures de chauffage par résistance (16) (13) sur le côté du réacteur, consiste à ajouter Al2O3 et C (carbone) pour le démarrage et à faire fondre le mélange de manière à fournir un laitier (Al2O3-Al4C3) ayant une température comprise entre approximativement 1 875 °C et 2 000 °C; puis à ajouter Al4C3 au laitier et à augmenter la température du four (11) de manière à former une phase supérieure de Al avec 6 à 8 % en poids de C (21) et une phase de laitier inférieure (22); puis à ajouter Al2O3 à la phase Al-C/au laitier (21, 22) afin de produire un laitier riche en Al2O3 à une température inférieure à la température du réactif et à produire une réaction de décarbonisation (étape 30) fournissant une phase supérieure de Al avec moins de 5 % en poids de C (23) qui est alors prélevée après l'étape (40). Le laitier restant constitue la matière de départ.
EP05794450A 2004-09-01 2005-09-01 Procede utilisant une reduction carbothermique en four unique avec regulation de la temperature a l'interieur du four Withdrawn EP1794333A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/932,846 US20060042413A1 (en) 2004-09-01 2004-09-01 Method using single furnace carbothermic reduction with temperature control within the furnace
PCT/US2005/031521 WO2006026771A2 (fr) 2004-09-01 2005-09-01 Procede utilisant une reduction carbothermique en four unique avec regulation de la temperature a l'interieur du four

Publications (1)

Publication Number Publication Date
EP1794333A2 true EP1794333A2 (fr) 2007-06-13

Family

ID=35941150

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05794450A Withdrawn EP1794333A2 (fr) 2004-09-01 2005-09-01 Procede utilisant une reduction carbothermique en four unique avec regulation de la temperature a l'interieur du four

Country Status (11)

Country Link
US (1) US20060042413A1 (fr)
EP (1) EP1794333A2 (fr)
JP (1) JP2008511760A (fr)
CN (1) CN101023190A (fr)
AU (1) AU2005279732A1 (fr)
BR (1) BRPI0514819A (fr)
CA (1) CA2577565A1 (fr)
NO (1) NO20070674L (fr)
RU (1) RU2007111945A (fr)
WO (1) WO2006026771A2 (fr)
ZA (1) ZA200702572B (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE517844T1 (de) 2005-07-27 2011-08-15 Thermical Ip Pty Ltd Carbothermische verfahren
US20080016984A1 (en) * 2006-07-20 2008-01-24 Alcoa Inc. Systems and methods for carbothermically producing aluminum
US7556667B2 (en) 2007-02-16 2009-07-07 Alcoa Inc. Low carbon aluminum production method using single furnace carbothermic reduction operated in batch mode
US7753988B2 (en) * 2007-07-09 2010-07-13 Alcoa Inc. Use of alumina-carbon agglomerates in the carbothermic production of aluminum
US7704443B2 (en) * 2007-12-04 2010-04-27 Alcoa, Inc. Carbothermic aluminum production apparatus, systems and methods
CN102066591B (zh) * 2008-05-09 2014-12-17 瑟米克尔Ip公司 碳热还原法
US9068246B2 (en) * 2008-12-15 2015-06-30 Alcon Inc. Decarbonization process for carbothermically produced aluminum
KR101105437B1 (ko) * 2010-05-11 2012-01-17 (주)포스코켐텍 폐 마그카본 내화물의 재생방법
NO337267B1 (no) * 2014-02-10 2016-02-29 Elkem As Fremgangsmåte for fremstilling av aluminiumoksidpartikler

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US2974032A (en) * 1960-02-24 1961-03-07 Pechiney Reduction of alumina
US4033757A (en) * 1975-09-05 1977-07-05 Reynolds Metals Company Carbothermic reduction process
GB1590431A (en) * 1976-05-28 1981-06-03 Alcan Res & Dev Process for the production of aluminium
GB1565065A (en) * 1976-08-23 1980-04-16 Tetronics Res & Dev Co Ltd Carbothermal production of aluminium
US4216010A (en) * 1979-01-31 1980-08-05 Reynolds Metals Company Aluminum purification system
US4334917A (en) * 1980-04-16 1982-06-15 Reynolds Metals Company Carbothermic reduction furnace
US4388107A (en) * 1979-01-31 1983-06-14 Reynolds Metals Company Minimum-energy process for carbothermic reduction of alumina
DE2948640C2 (de) * 1979-12-04 1984-12-20 Vereinigte Aluminium-Werke AG, 1000 Berlin und 5300 Bonn Verfahren und Vorrichtung zur thermischen Gewinnung von Aluminium
US4409021A (en) * 1982-05-06 1983-10-11 Reynolds Metals Company Slag decarbonization with a phase inversion
US4533386A (en) * 1984-03-27 1985-08-06 Process Development Associates, Inc. Process for producing aluminum
PT1147236E (pt) * 1999-01-08 2004-10-29 Alcoa Inc Producao de aluminio carbotermico usando refugo de aluminio como refrigerante
US6440193B1 (en) * 2001-05-21 2002-08-27 Alcoa Inc. Method and reactor for production of aluminum by carbothermic reduction of alumina
US6530970B2 (en) * 2001-05-21 2003-03-11 Alcoa Inc. Method for recovering aluminum vapor and aluminum suboxide from off-gases during production of aluminum by carbothermic reduction of alumina
US6805723B2 (en) * 2003-03-06 2004-10-19 Alcoa Inc. Method and reactor for production of aluminum by carbothermic reduction of alumina

Non-Patent Citations (1)

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Title
See references of WO2006026771A2 *

Also Published As

Publication number Publication date
CA2577565A1 (fr) 2006-03-09
ZA200702572B (en) 2008-09-25
RU2007111945A (ru) 2008-10-10
WO2006026771A3 (fr) 2006-12-14
BRPI0514819A (pt) 2008-06-24
US20060042413A1 (en) 2006-03-02
WO2006026771A2 (fr) 2006-03-09
JP2008511760A (ja) 2008-04-17
NO20070674L (no) 2007-02-06
AU2005279732A1 (en) 2006-03-09
CN101023190A (zh) 2007-08-22

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