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US20070246347A1 - Scraper for a Device for Breaking Bath Crust in an Electrolytic Cell Intended for Aluminium Production - Google Patents

Scraper for a Device for Breaking Bath Crust in an Electrolytic Cell Intended for Aluminium Production Download PDF

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Publication number
US20070246347A1
US20070246347A1 US11/571,132 US57113205A US2007246347A1 US 20070246347 A1 US20070246347 A1 US 20070246347A1 US 57113205 A US57113205 A US 57113205A US 2007246347 A1 US2007246347 A1 US 2007246347A1
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US
United States
Prior art keywords
scraper
crust breaking
crust
fingers
breaking member
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.)
Abandoned
Application number
US11/571,132
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English (en)
Inventor
Bernard Bourges
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Individual
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of US20070246347A1 publication Critical patent/US20070246347A1/en
Abandoned legal-status Critical Current

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    • 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
    • C25C3/14—Devices for feeding or crust breaking

Definitions

  • the invention relates to electrolytic cell equipment intended for the production of aluminium by fused bath electrolysis according to the Hall-Heroult process.
  • it relates to devices for breaking solid bath crusts in the said electrolytic cells.
  • the alumina and bath compounds are usually added into the bath in the form of a powder.
  • Electrolytic cells are usually equipped with one or several powder distributors associated with a device for breaking the alumina and solidified electrolyte crust that covers the bath surface during normal operation, so that the powder material can be added into the electrolyte bath.
  • the crust breaking device usually comprises a jack and a crust breaking member called a “crust breaker”, “plunger” or “crust breaker chisel” fixed to the end of the jack rod.
  • the crust breaker usually placed vertically, is lowered by activation of the jack and breaks the alumina and solidified bath crust.
  • the crust breaking devices usually also comprise a scraper to eliminate solidified bath depositions that tend to form on crust breakers.
  • the solidified bath sometimes forms an envelope on the surface of the crust-breaking member that can block the member in the scraper.
  • the Applicant attempted to find means of avoiding this disadvantage.
  • An object of the invention is a scraper for a crust breaking member (such as a crust breaker, a plunger or a crust breaker chisel) useable to form an opening in an alumina and solidified bath crust in a fused bath electrolytic cell by a back and forth motion of the crust breaking member along a translation axis T.
  • a crust breaking member such as a crust breaker, a plunger or a crust breaker chisel
  • the scraper according to the invention comprises at least three fingers arranged around a reference axis S that will coincide with the said translation axis T during use so as to form a space called a “clearance” between the fingers and the crust breaking member, and each finger comprises at least one scraping member projecting towards the crust breaking member.
  • the Applicant had the idea of separating the scraper into a set of scraping members separated from each other, reducing the contact area with the scraper and arranging the scraping members on a plurality of fingers at an angle spacing from each other. This approach prevents the crust breaking member from getting blocked by limiting the force necessary to bring it free if there is an accumulation of bath crust between the scraping members and the crust breaking member.
  • the applicant also had the idea of moving the fingers well away from the crust breaking member of the crust breaking device, so as to encourage the accumulation of bath crust debris above the scraping members, rather than their insertion between the jacket and the crust breaking member. The accumulated debris can then easily be evacuated through the space formed by the separation between the scraper fingers.
  • the invention is particularly suitable for the electrolytic cells to be used for aluminium production.
  • Another object of the invention is a crust breaking device intended for an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention.
  • Another object of the invention is a crust breaker - feeder for use in an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention.
  • Another object of the invention is a crust breaking and measurement device intended for use in an aluminium production cell using fused bath electrolysis and comprising a scraper according to the invention.
  • Another object of the invention is the use of the scraper according to the invention in an electrolytic cell intended for the production of aluminium by fused bath electrolysis.
  • FIG. 1 is a simplified diagram showing a partial inner view of a typical electrolytic cell intended for the production of aluminium by fused bath electrolysis, seen in a vertical section.
  • FIG. 2 shows a perspective view of a preferred embodiment of the scraper according to the invention.
  • FIG. 3 shows a side view of the scraper in FIG. 2 .
  • FIGS. 4 and 5 show sectional views of the scraper in FIG. 2 , along the sectional planes indicated in FIG. 3 .
  • FIG. 6 shows a perspective view of the scraper in FIG. 2 fixed to the end of a crust breaking device.
  • an electrolytic cell ( 1 ) for aluminium production by fused bath electrolysis in other words by molten salt electrolysis, comprises a pot ( 2 ), one or several anodes ( 3 ) (typically prebaked anodes made of a carbonaceous material), and feeding means for powder materials ( 20 , 30 ), usually fixed to a superstructure ( 4 ) arranged above the pot.
  • the electrolytic pot ( 2 ) comprises inner lining means (not shown) and a cathode assembly ( 5 ) that form a crucible inside the pot ( 2 ) that can contain the electrolytic bath and a liquid aluminium pad ( 6 ) when the cell is in operation.
  • the anodes ( 3 ) are normally partially immersed in the liquid electrolytic bath ( 7 ) and the cells are operated so as to form an alumina and solidified bath crust ( 10 ) above the electrolytic bath.
  • the powder material supply means ( 20 , 30 ) usually comprise a powder material distributor ( 20 ) and a crust breaking device ( 30 ).
  • the powder material distributor ( 20 ) typically comprises a hopper ( 21 ) that will contain a reserve of powder material, and a chute ( 22 ) fixed to the lower part of the hopper and intended to carry the powder material close to an opening ( 11 ) in the crust ( 10 ).
  • the crust breaking device ( 30 ) comprises an actuator ( 31 ) and a crust breaking member ( 33 ) (often called a “crust breaker”, “plunger” or “crust breaker chisel”) fixed to the end of the actuator rod which is typically located in a jacket or sheath ( 32 ).
  • the crust breaking member ( 33 ) is usually arranged so as to enter into and exit from the crust breaking device ( 30 ) through an opening located at the free end ( 34 ) of the jacket or sheath ( 32 ).
  • the crust breaking member ( 33 ) forms an opening ( 11 ) in an alumina and solidified bath crust ( 10 ) by a to and fro movement of the crust breaking member ( 33 ) along a translation axis T that is typically vertical or slightly inclined from the vertical.
  • the cross-section of the crust breaking member ( 33 ) is typically circular.
  • the actuator ( 31 ) is typically a pneumatic actuator such as a pneumatic jack.
  • a scraper ( 40 ) cleans the crust breaking member during its to and fro movements.
  • a powder material distributor can be associated with one or several predetermined crust breaking devices, or conversely a crust breaking device may be associated with one or several determined powder material distributors.
  • Electrolytic cells are frequently used with one or several devices comprising a powder materials distributor and a crust breaker device. These devices are known under the term Crustbreaking and Feeding Devices.
  • At least one opening ( 11 ) is formed (or possibly kept open) in the said crust ( 10 ) between the anodes ( 3 ), using the crust breaking device(s) ( 30 ), and powder material is added into the electrolytic bath ( 7 ) through the opening ( 11 ) (or through at least one opening when there are several).
  • the scraper ( 40 ) comprises a plurality of fingers ( 42 ) arranged around a reference axis S that will be coincident with the said translation axis T during use.
  • the fingers ( 42 ) are arranged so as to leave a space ( 44 ) called a “clearance” between the fingers ( 42 ) and the crust breaking member ( 33 ).
  • Each finger ( 42 ) comprises at least one scraping member ( 43 ) that projects towards the crust breaking member ( 33 ).
  • FIGS. 2 to 6 show a preferred embodiment of a scraper according to the invention.
  • the scraper ( 40 ) according to the invention comprises at least three fingers ( 42 ) and preferably at least 6 fingers.
  • the number of fingers is usually between 6 and 10 inclusively.
  • the example embodiment of the invention shown in FIGS. 3 to 6 comprises six fingers.
  • the length L 1 of the fingers ( 42 ) is preferably more than 100 mm.
  • the fingers ( 42 ) are arranged so as to form a space between them, called a separation ( 422 , 423 ).
  • the cross section of the fingers ( 42 ) is advantageously substantially uniform over at least 50% of their length L 1 so as to maintain a spacing ( 422 , 423 ) over a significant length between the fingers, sufficient to facilitate evacuation of bath crust debris tom off by the scraping members ( 43 ).
  • the fingers ( 42 ) are preferably straight and parallel to the reference axis S of the scraper.
  • the distance Cm between the points closest to the surface of the adjacent fingers is preferably greater than 10 mm, and more preferably greater than 20 mm over at least 50% of their length L 1 , to enable efficient evacuation of bath crust debris produced by scraping.
  • the separation C between adjacent fingers preferably increases with increasing distance from S axis, in other words the distance between the inside and the outside of the scraper, so as to form an opening that flares outwards, and thus to facilitate evacuation of bath crust debris towards the outside of the scraper. In the example shown in FIG. 5 , the separation C between the inner end ( 425 ) of the fingers and their outer end ( 426 ) increases.
  • the fingers ( 42 ) comprise at least a first plane surface element ( 424 ) and a second plane surface element ( 424 ′) arranged so that the first surface element ( 424 ) of each finger and the second surface element ( 424 ′) of an adjacent finger are facing each other and at an angle from each other so as to form an opening that flares towards the outside of the scraper.
  • the said facing surfaces ( 424 , 424 ′) are preferably separated by an angle ⁇ of more than 10° with respect to the said S axis, so as to create a sufficient spacing ( 422 , 423 ) between the fingers to enable evacuation of bath crust debris produced by scraping.
  • the angular centre-to-centre spacing ⁇ between the fingers is typically between 20° and 90°.
  • Each scraping member ( 43 ) is preferably arranged on the fingers ( 42 ) so as to leave a free space ( 45 ) called a “scraping space” between the scraping member ( 43 ) and the crust breaking member ( 33 ). More precisely, each scraping member ( 43 ) comprises one end ( 431 ) called the “scraping end” located at a determined distance D 1 from the said axis S so as to leave the said scraping space. The determined distance D 1 is advantageously the same for all scraping ends ( 431 ).
  • the scraping space ( 45 ) is typically between 1 and 5 mm inclusively.
  • the scraping distance D 1 is less than the clearance ( 44 ) (corresponding to a constant separation E in the embodiment shown in FIGS. 3 to 6 ).
  • the scraping member ( 43 ) thus forms a projection facing towards the crust breaking member ( 33 ).
  • each scraping member ( 43 ) is located at the free end ( 420 ) of each finger ( 42 ).
  • the scraping end ( 431 ) is in the form of a concave surface.
  • the length L 2 of this surface along the direction of the S axis is typically between 10 mm and 50 mm and more typically between 10 mm and 30 mm.
  • the area of the concave surface is typically between 10 and 1000 mm 2 .
  • the said concave surface is typically parallel to the outer lateral surface ( 331 ) of the crust breaking member ( 33 ), in other words it matches the shape of the lateral outer surface ( 331 ).
  • the scraping end ( 431 ) is in the form of a tip or an edge.
  • the fingers ( 42 ) are typically fixed to a support element ( 41 ).
  • the scraping members ( 43 ) are preferably arranged at a determined distance D 3 from the support element ( 41 ) equal to at least 100 mm.
  • the scraper ( 40 ) is advantageously removable so that it can be changed, particularly in the case of damage or wear.
  • the support element ( 41 ) typically comprises attachment means ( 410 , 411 ) such as a collar or flange ( 410 ) provided with through holes ( 411 ).
  • the attachment means ( 410 , 411 ) are used to fix the scraper to a crust breaking device, typically to the end ( 34 ) of a sheath (or jacket) ( 32 ) from which the crust breaking member ( 33 ) projects.
  • the support element or body ( 41 ) and the fingers ( 42 ) are typically in a single part.
  • the fingers ( 42 ) are typically made of steel to achieve sufficient stiffness.
  • FIGS. 4 and 5 show the different parameters for a scraper according to a preferred embodiment of the invention, in which the fingers are straight and have a substantially uniform cross section over more than 50% of their length L 1 , and for a crust breaking member ( 33 ) with a circular section.
  • R is the radius of the crust breaking member ( 33 )
  • D 1 is the said determined distance
  • D 2 is the distance between the S axis and the central axis of the fingers ( 42 )
  • E is the said clearance.
  • the scraper ( 40 ) according to the invention may advantageously be used on crust breaking devices ( 30 ) used in aluminium production cells by fused bath electrolysis with a crust breaking member free to move in translation along a T axis.
  • it can advantageously be used on crust-breakers—feeders, like those described above, for use in aluminium production cells by fused bath electrolysis.
  • the scraper ( 40 ) according to the invention can be fitted on crust breaking and measurement devices like that described in patent EP 0 716 165 (corresponding to American patent U.S. Pat. No. 6,065,867) in the name of Aluminium Pechiney.
  • the crust breaking member also comprises measurement means such as a thermocouple, or can be used as a measurement means (for example for use as an electric contact tip to detect when the member comes into contact with the liquid electrolytic bath during its vertical movements).

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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)
US11/571,132 2004-06-25 2005-06-22 Scraper for a Device for Breaking Bath Crust in an Electrolytic Cell Intended for Aluminium Production Abandoned US20070246347A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0406953 2004-06-25
FR0406953A FR2872176B1 (fr) 2004-06-25 2004-06-25 Racleur d'un organe de percage d'une croute de bain d'une cellule d'electrolyse destinee a la production d'aluminium
PCT/FR2005/001573 WO2006010818A2 (fr) 2004-06-25 2005-06-22 Racleur d'un organe de percage d'une croûte de bain d'une cellule d'électrolyse destinée à la production d'aluminium

Publications (1)

Publication Number Publication Date
US20070246347A1 true US20070246347A1 (en) 2007-10-25

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ID=34947387

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US11/571,132 Abandoned US20070246347A1 (en) 2004-06-25 2005-06-22 Scraper for a Device for Breaking Bath Crust in an Electrolytic Cell Intended for Aluminium Production

Country Status (11)

Country Link
US (1) US20070246347A1 (fr)
EP (1) EP1774062B1 (fr)
CN (1) CN100567579C (fr)
AR (1) AR052761A1 (fr)
AT (1) ATE478979T1 (fr)
AU (1) AU2005266290B2 (fr)
CA (1) CA2570550A1 (fr)
DE (1) DE602005023169D1 (fr)
FR (1) FR2872176B1 (fr)
WO (1) WO2006010818A2 (fr)
ZA (1) ZA200700135B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK179337B1 (en) * 2014-01-27 2018-05-14 Rio Tinto Alcan Int Ltd Device for drilling a crust of a cryolite bath that can be positioned on the periphery of an electrolytic cell

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7828462B2 (en) 2006-04-10 2010-11-09 Jensen Bradford B Imitation candle with simulated lighted wick using external light source
CN101413137B (zh) * 2008-05-20 2010-08-04 许磊 刮削式打壳装置
CN107497793B (zh) * 2017-09-30 2024-03-12 中冶赛迪技术研究中心有限公司 一种铝槽打壳锤头超声振动清洗装置及方法
FR3077018B1 (fr) * 2018-01-24 2020-01-24 Rio Tinto Alcan International Limited Dispositif de percage comprenant un fourreau tubulaire fixe a un verin
CN112725838A (zh) * 2021-01-19 2021-04-30 黄文强 一种电解铝槽打壳装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4349231A (en) * 1979-09-10 1982-09-14 Swiss Aluminium Ltd. Chisel alignment unit for a crust breaking facility
US4437964A (en) * 1982-05-27 1984-03-20 Aluminium Pechiney Assembly for spot feeding alumina to an electrolytic tank for the production of aluminum
US6065867A (en) * 1994-12-09 2000-05-23 Aluminium Pechiney Method and device for measuring the temperature and the level of the molten electrolysis bath in cells for aluminum production
US20060231385A1 (en) * 2005-04-19 2006-10-19 Aluminium Pechiney Device for controlling the travel distance of a chisel in a feeding system for an aluminium production electrolytic cell
US20070034520A1 (en) * 2003-10-02 2007-02-15 Claude Ritter Method and system for controlling addition of powdery materials into the bath of an electrolysis cell for the production of aluminium
US7497861B2 (en) * 2006-01-30 2009-03-03 Warsaw Orthopedic, Inc. Chisel system for osteochondral implants and a surgical procedure involving same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2623704Y (zh) * 2003-06-13 2004-07-07 沈阳铝镁设计研究院 一种打壳锤头

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4349231A (en) * 1979-09-10 1982-09-14 Swiss Aluminium Ltd. Chisel alignment unit for a crust breaking facility
US4437964A (en) * 1982-05-27 1984-03-20 Aluminium Pechiney Assembly for spot feeding alumina to an electrolytic tank for the production of aluminum
US6065867A (en) * 1994-12-09 2000-05-23 Aluminium Pechiney Method and device for measuring the temperature and the level of the molten electrolysis bath in cells for aluminum production
US20070034520A1 (en) * 2003-10-02 2007-02-15 Claude Ritter Method and system for controlling addition of powdery materials into the bath of an electrolysis cell for the production of aluminium
US7504016B2 (en) * 2003-10-02 2009-03-17 Aluminum Pechiney Method and system for controlling addition of powdery materials into the bath of an electrolysis cell for the production of aluminium
US20060231385A1 (en) * 2005-04-19 2006-10-19 Aluminium Pechiney Device for controlling the travel distance of a chisel in a feeding system for an aluminium production electrolytic cell
US7429314B2 (en) * 2005-04-19 2008-09-30 Aluminium Pechiney Device for controlling the travel distance of a chisel in a feeding system for an aluminium production electrolytic cell
US7497861B2 (en) * 2006-01-30 2009-03-03 Warsaw Orthopedic, Inc. Chisel system for osteochondral implants and a surgical procedure involving same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK179337B1 (en) * 2014-01-27 2018-05-14 Rio Tinto Alcan Int Ltd Device for drilling a crust of a cryolite bath that can be positioned on the periphery of an electrolytic cell

Also Published As

Publication number Publication date
DE602005023169D1 (de) 2010-10-07
FR2872176A1 (fr) 2005-12-30
CA2570550A1 (fr) 2006-02-02
EP1774062A2 (fr) 2007-04-18
FR2872176B1 (fr) 2006-07-28
ZA200700135B (en) 2008-06-25
AR052761A1 (es) 2007-04-04
AU2005266290A1 (en) 2006-02-02
AU2005266290B2 (en) 2009-12-24
CN1977069A (zh) 2007-06-06
EP1774062B1 (fr) 2010-08-25
WO2006010818A3 (fr) 2006-10-05
CN100567579C (zh) 2009-12-09
ATE478979T1 (de) 2010-09-15
WO2006010818A2 (fr) 2006-02-02

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