EP1344845A1 - Brique réfractaire imprégnée de brai - Google Patents

Brique réfractaire imprégnée de brai Download PDF

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Publication number
EP1344845A1
EP1344845A1 EP02005613A EP02005613A EP1344845A1 EP 1344845 A1 EP1344845 A1 EP 1344845A1 EP 02005613 A EP02005613 A EP 02005613A EP 02005613 A EP02005613 A EP 02005613A EP 1344845 A1 EP1344845 A1 EP 1344845A1
Authority
EP
European Patent Office
Prior art keywords
pitch
bricks
lining
impregnated
resins
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Withdrawn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
EP02005613A
Other languages
German (de)
English (en)
Inventor
Siegfried c/o VAM Al-Tech GmbH Wilkening
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.)
VAW Aluminium-Technologie GmbH
Original Assignee
VAW Aluminium-Technologie GmbH
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 VAW Aluminium-Technologie GmbH filed Critical VAW Aluminium-Technologie GmbH
Priority to EP02005613A priority Critical patent/EP1344845A1/fr
Publication of EP1344845A1 publication Critical patent/EP1344845A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
    • C25C3/085—Cell construction, e.g. bottoms, walls, cathodes characterised by its non electrically conducting heat insulating parts

Definitions

  • the invention is related to the improvement of refractory materials for the lining of electrolytic reduction cells as used for the winning of aluminium by molten salt electrolysis.
  • FIG. 1 A typical example of a reduction cell lining is shown in Figure 1.
  • the bottom of the electrolysis basin consists of carbon or graphite cathode blocks (1).
  • Steel collector bars (2) are embedded in the cathode blocks and serve as electrical connection to the outside of the potshell (3).
  • Carbon materials (4) are also used as a major part of the side wall lining of the cell, particularly in contact with the liquid metal pad on the cathode bottom as well as with the electrolytic melt above the metal.
  • the main component of the electrolyte is molten cryolite. It contains a few percent of dissolved alumina and some other additives such as aluminium and calcium fluoride.
  • the cell operating temperatures range from 950 to 970°C.
  • fireclay bricks (5) are commonly applied as back material of the carbon cathode bottom and carbon side wall lining.
  • the carbon materials at the hot or front face of the electrolysis cell are pervious to the cryolitic melt.
  • the fireclay bricks are impregnated by cryolite, react with it and are partially converted to a magma-like slag.
  • electrolyte constituents penetrate deeper into the refractory lining, degrade its insulation capacity and cause swelling and softening of the fireclay bricks. The insulating and structural conditions become even worth when the light-weight insulation bricks (6) in the outer zone of the potshell lining are affected.
  • the objective of the invention is to effectively improve the resistance of the refractory, especially of the fireclay bricks against cryolite. This can be achieved by filling the open pore volume of the refractory bricks with impregnating pitch.
  • the procedure of pitch impregnation is carried out as follows: The refractory bricks are placed in an impregnation autoclave where they are pre-heated to 150 - 250°C. Preheating of the bricks can also be done outside the autoclave prior to the impregnation process. The autoclave and the bricks are evacuated. Thereafter the bricks are flooded with liquid impregnating pitch. After pitch flooding pressure of 5 - 10 bar is applied (compressed air or nitrogen) to press the liquid pitch into the open pores. When thorough impregnation is completed, the pitch is withdrawn and the bricks are taken out from the autoclave.
  • the impregnated bricks may be directly used in the reduction cell lining if their number is limited. During heating up of the reduction cell, fumes and volatiles are released from the pitch due to its carbonization. Therefore, good ventilation and fume collection is required at the cell operating temperature. For environmental reasons it is more advantageous to subject the pitch-impregnated refractory bricks to a carbonization or coking process in dedicated furnaces up to 1000°C.
  • the cryolite resistance of normal, non-impregnated fireclay bricks was compared with pitch-impregnated heat-treated fireclay bricks by two testing methods, namely the "finger” and the "cup” test. Both well-established tests showed distinct differences in cryolite resistance between the two preceding types of bricks.
  • the non-impregnated fireclay brick is strongly attacked and a substantial portion of the brick material is dissolved and scorified.
  • the pitch-impregnated brick did practically not indicate any sign of surface erosion and slagging. Plant tests proved this result and the favourable behaviour of the pitch-impregnated fireclay bricks.
  • the pitch-impregnated bricks are preferably laid adjacent to the carbon (4) or graphite lining materials (7), i.e. under the cathode blocks and below or behind the carbon material in the side lining.
  • the new refractory brick for the lining of aluminium reduction cells is characterized in that the open pore volume of fireclay bricks or other ceramic bricks is fully impregnated with pitch or resins of high carbon residue to provide a superior resistance of the impregnated bricks against components and reaction products of cryolite-based melts as well as against molten aluminium.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
EP02005613A 2002-03-12 2002-03-12 Brique réfractaire imprégnée de brai Withdrawn EP1344845A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP02005613A EP1344845A1 (fr) 2002-03-12 2002-03-12 Brique réfractaire imprégnée de brai

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP02005613A EP1344845A1 (fr) 2002-03-12 2002-03-12 Brique réfractaire imprégnée de brai

Publications (1)

Publication Number Publication Date
EP1344845A1 true EP1344845A1 (fr) 2003-09-17

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ID=27763364

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02005613A Withdrawn EP1344845A1 (fr) 2002-03-12 2002-03-12 Brique réfractaire imprégnée de brai

Country Status (1)

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EP (1) EP1344845A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105463506A (zh) * 2016-01-13 2016-04-06 重庆大学 一种分离回收铝电解质阳极碳渣中电解质和碳的方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071593A (en) * 1973-11-06 1978-01-31 General Refractories Company Process for making a pitch impregnated, cold molded refractory article
GB1593161A (en) * 1978-04-28 1981-07-15 Steetley Refractories Ltd Refractory materials
RU2081208C1 (ru) * 1993-04-05 1997-06-10 Товарищество с ограниченной ответственностью "Межотраслевой центр проблем экологии и эффективности производства алюминия" Способ защиты футеровки алюминиевого электролизера

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071593A (en) * 1973-11-06 1978-01-31 General Refractories Company Process for making a pitch impregnated, cold molded refractory article
GB1593161A (en) * 1978-04-28 1981-07-15 Steetley Refractories Ltd Refractory materials
RU2081208C1 (ru) * 1993-04-05 1997-06-10 Товарищество с ограниченной ответственностью "Межотраслевой центр проблем экологии и эффективности производства алюминия" Способ защиты футеровки алюминиевого электролизера

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 199807, Derwent World Patents Index; Class M28, AN 1998-075551, XP002210681 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105463506A (zh) * 2016-01-13 2016-04-06 重庆大学 一种分离回收铝电解质阳极碳渣中电解质和碳的方法

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