CA1330320C - Collars for the protection of anode hangers in aluminium electrolysis cells - Google Patents
Collars for the protection of anode hangers in aluminium electrolysis cellsInfo
- Publication number
- CA1330320C CA1330320C CA 587536 CA587536A CA1330320C CA 1330320 C CA1330320 C CA 1330320C CA 587536 CA587536 CA 587536 CA 587536 A CA587536 A CA 587536A CA 1330320 C CA1330320 C CA 1330320C
- Authority
- CA
- Canada
- Prior art keywords
- anode
- collar
- protecting
- cardboard
- collars
- 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.)
- Expired - Fee Related
Links
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
- C25C3/12—Anodes
- C25C3/125—Anodes based on carbon
Abstract
Abstract A protecting collar is being used in connection with the use of a protecting cover of carbonaceous paste (6) over the casting connection (7) between a carbon anode (2) and nipples (4) of an anode hanger (1), and around the lower part of the nipples (4). The collar (5,8,9) is placed around the nipples, and the carbonaceous paste is thereafter provided in the spacing between the collar and the nipple. It is made of cardboard, preferably brown paste board.
Description
3~320 The present invention relates to a protecting collar being used in connection wi~h the application of a protectin~
cover in the form of a carbonaceous paste on the cast connection - between a carbon anode and ~he nipples or studs of an anode hanger -, and around the lower part of the nipples, as described below.
Aluminium is mostly produced by electrolysis of aluminium oxide dissolved in a cryolite bath. The electrolysis cells enabling this consist of a carbon cathode disposed in a steel shell which on the inside is thermally insulated with refractory materials. A carbon anode, or several carbon anode i~
~ bodies are provided above the carbon cathode and are partly -~` submerged in the cryolite bath. Thus tha oxygen stemming from the ~-~
~ 1, decomposition of the aluminium oxide will gradually oxidize the carbon anode bodies. ~-Electric current is led from the top to the bottom of the cells, and the cryolite ls kept in its melted condition by i means of the Joule-effect at a temperature close to the solidification temperature. The most common temperatures for these cells are between 930 and 980 C. The aluminium produced is therefore in a liquid state and is deposited on the carbon cathode due to gravity. The aluminium produced, or part of the ~` aluminium produced, is regularly removed from the cell by means of - a suction pump and transferred to a casting ladle, and is in turn ' decanted to a melting pot.
I The carbon anode bodies are fixedly connected to ;j s~ so-called anode hangers, and to obtain good electrical and `i mechanical connectlon the anode hangers are releasably fixed to 1 .
., .
- ~33~320 26625-8~
the anode bar by means of a clamping device. As ~he carbon bodies - l ~ are gradually consumed and as aluminium metal is removed from the ,j cells (the metal actually represents the cathode) r the anode bar, with the carbon anodes attached thereto, is lowered to keep a ~ constant distance between the bottom side of the anodes and the -~i cathode.
In an electrolysis cell of common size there are about 20-30 carbon anodes, and since these anodes are consumed gradually, they have to be changed after 20-30 days, depending on the size of the anodes. Thus, in each cell there i~ one anode exchanged every day.
As mentioned above, the carbon bodies are fixedly connected to anode hangers. The anode hangers serve two -different `
purposes, namely to keep the carbon bodies at a predetermined distance from the cathode, and to conduct the electric current from the anode bar down through the carbon bodies.
The amperage for the electrolysis cell lies between 100 000 and 300 000 amps.
Electric current connections and bus bars are therefore i 20 made of industrial metals wlth good electric conductlvity i.e.
usually pure copper or aluminium.
Since the lower part of the anode hangers are situated close to the cryolite bath which has high temperature, this part of the anode hanger is, however, made of material which is resistant with regard to the high temperature, i.e. usually s~eel.
In terms of construction, the steel part of the anode hanger consists of a cross member or bar with two or more ;;;
3~320 26625-~4 downwardly protruding cylindrical nipples, while the upper part of the anode han~er has a rectangular or quadratic cross section and is welded or in some o~her way connected to the st~el part.
The anode hangers are connected to carbon bodies through a casting connection using cast iron.
Around the lower part of the nipples and over the cast -connectlon is provided a protecting ring of carbonaceous pas~e.
, This is done by firstly placing a pro~ecting collar around the 3 nipples and then afterwards filling up the spacing between the lQ collar and the nipples with the carbonaceous paste. The protecting ring of carbonaceous paste is finally hardened approximately 24 hours af~er the carbon anode has been inserted into the cell and prevents the electrolytic bath from coming into contact with the steel and the cast iron. Such contact is liable to cause dissolution of the iron and steel whlch in turn may ` result in the nipple and cast iron becoming corroded such that the `` carbon falls off the nipples.
The protecting collars which up until today have been employed having, due to the high temperature, been made of alumlnium material. These aluminium collars have however been expensive to manufacture and to use. This is at least in part due to the fact that it is expensive to remove the aluminium material before the anode butts are crushed (the carbon is reused).
Surprisingly, in spite of the high temperature of the cast iron during the casting operation and the high temperature of the electrolytic bath i~ has according to the invention been found that the collars can be manufac~ured from paste-board or brown 33~320 26625-8~
cardboard. Hereby large savings have been achieved with regard to reduced manufacturing costs. Further, it has been possible to avoid the problems related to the cleaning of the anode hangers as the cardboard collars burn away during the electrolysis process due to the high temperature, but after the carbonaceous paste has hardened. ~ `
According to a broad aspec~ of the presen~ invention, there is provided a protective collar for use with an anode hanger ! "
for supporting an anode in an electrolytic cell for the production of aluminium by electrolysis, the anode hanger comprising a bar from which stubs protrude, the stubs being connected to the anode by means of cast iron connections, a protecting ring of carbonaceous paste being formed by pouring the paste within collars to form a cover over the cast iron and around the lower part of the stub, characterised in that each collar is made of cardboard.
The invention will now be further descrlbed by way o~
examples and with reference to the drawings in which, Figure 1 shows an anode hanger onto which is mounted a carbon anode, Figure 2 shows an enlarged section of the connection between a nipple and the carbon anode shown in Figure 1, ~`
Figure 3 shows an example of a cardboard collar -according to the invention, and Figure 4 shows another example o~ a cardboard collar according to the invention.
: :
~ 33~3~0 Figure 1 shows as mentioned above an anode hanger 1 which has mounted thereto a so-called prebaked carbon anode 2 , which is used in cells producing aluminium by electrolysis.
`', The anode hanger 1 consists of an upper part, anode rod 3, of aluminium, and a lower part of steel. The steel part further consists of a cross member or bar 15 which is provided with three downwardly protruding nipples or studs 4.
The carbon anode 2 is fixedly connected to the nipples 4 ~ by means of a cast connection 7 (cast iron) as shown in Figure 2.
- 10 Over the cast connection 7 and around the lower part of the nipp]es is provided a protecting ring 6 made of carbonaceous - paste. This is, as previously mentioned, made by at first placing a protecting collar 5 around the nipples 4 and thereafter filling up the empty space between the collar and the nipple.
, In Figure ~ is shown an example of a pro~ecting collar 8 ; of cardboard according to the invention. The collar is made of a piece of cardboard strip which is provided with a locking arrangement at its ends. The locking arrangement as here shown ~ consists of locking tongue 10 and a slit or slot 12.
s 20 The collar is shaped, as will be apparent ~rom Figuxe 3, by bending the collar so that the tongue may be lead through the ! slit 12. Cuts 11 at the inner end of the tongue provides barbs which prevent the tongue from being pulled out of the slit.
, :.
.
Figure ~ shows another locking arrangement. Here the cardboard strip 9 is at its ends provided with transverse cuts 13,14 stretching from the side edge to the centre line in opposition directions. The collar is shaped by endlng the .;,'; . S
.: ~
~ 3~20 cardboard strip and letting the two slots (cuts) 13,14 grip into one another.
The invention is not in any way limited to the above examples. Thus the collars may be made of cardboard strips where the ends are overlapping one another and are fixed by means of gluing, a locking pln or the like.
'~
`; '. ' .` `
',; ' ~ ,"
'"`'"'.'.;''"",;''
cover in the form of a carbonaceous paste on the cast connection - between a carbon anode and ~he nipples or studs of an anode hanger -, and around the lower part of the nipples, as described below.
Aluminium is mostly produced by electrolysis of aluminium oxide dissolved in a cryolite bath. The electrolysis cells enabling this consist of a carbon cathode disposed in a steel shell which on the inside is thermally insulated with refractory materials. A carbon anode, or several carbon anode i~
~ bodies are provided above the carbon cathode and are partly -~` submerged in the cryolite bath. Thus tha oxygen stemming from the ~-~
~ 1, decomposition of the aluminium oxide will gradually oxidize the carbon anode bodies. ~-Electric current is led from the top to the bottom of the cells, and the cryolite ls kept in its melted condition by i means of the Joule-effect at a temperature close to the solidification temperature. The most common temperatures for these cells are between 930 and 980 C. The aluminium produced is therefore in a liquid state and is deposited on the carbon cathode due to gravity. The aluminium produced, or part of the ~` aluminium produced, is regularly removed from the cell by means of - a suction pump and transferred to a casting ladle, and is in turn ' decanted to a melting pot.
I The carbon anode bodies are fixedly connected to ;j s~ so-called anode hangers, and to obtain good electrical and `i mechanical connectlon the anode hangers are releasably fixed to 1 .
., .
- ~33~320 26625-8~
the anode bar by means of a clamping device. As ~he carbon bodies - l ~ are gradually consumed and as aluminium metal is removed from the ,j cells (the metal actually represents the cathode) r the anode bar, with the carbon anodes attached thereto, is lowered to keep a ~ constant distance between the bottom side of the anodes and the -~i cathode.
In an electrolysis cell of common size there are about 20-30 carbon anodes, and since these anodes are consumed gradually, they have to be changed after 20-30 days, depending on the size of the anodes. Thus, in each cell there i~ one anode exchanged every day.
As mentioned above, the carbon bodies are fixedly connected to anode hangers. The anode hangers serve two -different `
purposes, namely to keep the carbon bodies at a predetermined distance from the cathode, and to conduct the electric current from the anode bar down through the carbon bodies.
The amperage for the electrolysis cell lies between 100 000 and 300 000 amps.
Electric current connections and bus bars are therefore i 20 made of industrial metals wlth good electric conductlvity i.e.
usually pure copper or aluminium.
Since the lower part of the anode hangers are situated close to the cryolite bath which has high temperature, this part of the anode hanger is, however, made of material which is resistant with regard to the high temperature, i.e. usually s~eel.
In terms of construction, the steel part of the anode hanger consists of a cross member or bar with two or more ;;;
3~320 26625-~4 downwardly protruding cylindrical nipples, while the upper part of the anode han~er has a rectangular or quadratic cross section and is welded or in some o~her way connected to the st~el part.
The anode hangers are connected to carbon bodies through a casting connection using cast iron.
Around the lower part of the nipples and over the cast -connectlon is provided a protecting ring of carbonaceous pas~e.
, This is done by firstly placing a pro~ecting collar around the 3 nipples and then afterwards filling up the spacing between the lQ collar and the nipples with the carbonaceous paste. The protecting ring of carbonaceous paste is finally hardened approximately 24 hours af~er the carbon anode has been inserted into the cell and prevents the electrolytic bath from coming into contact with the steel and the cast iron. Such contact is liable to cause dissolution of the iron and steel whlch in turn may ` result in the nipple and cast iron becoming corroded such that the `` carbon falls off the nipples.
The protecting collars which up until today have been employed having, due to the high temperature, been made of alumlnium material. These aluminium collars have however been expensive to manufacture and to use. This is at least in part due to the fact that it is expensive to remove the aluminium material before the anode butts are crushed (the carbon is reused).
Surprisingly, in spite of the high temperature of the cast iron during the casting operation and the high temperature of the electrolytic bath i~ has according to the invention been found that the collars can be manufac~ured from paste-board or brown 33~320 26625-8~
cardboard. Hereby large savings have been achieved with regard to reduced manufacturing costs. Further, it has been possible to avoid the problems related to the cleaning of the anode hangers as the cardboard collars burn away during the electrolysis process due to the high temperature, but after the carbonaceous paste has hardened. ~ `
According to a broad aspec~ of the presen~ invention, there is provided a protective collar for use with an anode hanger ! "
for supporting an anode in an electrolytic cell for the production of aluminium by electrolysis, the anode hanger comprising a bar from which stubs protrude, the stubs being connected to the anode by means of cast iron connections, a protecting ring of carbonaceous paste being formed by pouring the paste within collars to form a cover over the cast iron and around the lower part of the stub, characterised in that each collar is made of cardboard.
The invention will now be further descrlbed by way o~
examples and with reference to the drawings in which, Figure 1 shows an anode hanger onto which is mounted a carbon anode, Figure 2 shows an enlarged section of the connection between a nipple and the carbon anode shown in Figure 1, ~`
Figure 3 shows an example of a cardboard collar -according to the invention, and Figure 4 shows another example o~ a cardboard collar according to the invention.
: :
~ 33~3~0 Figure 1 shows as mentioned above an anode hanger 1 which has mounted thereto a so-called prebaked carbon anode 2 , which is used in cells producing aluminium by electrolysis.
`', The anode hanger 1 consists of an upper part, anode rod 3, of aluminium, and a lower part of steel. The steel part further consists of a cross member or bar 15 which is provided with three downwardly protruding nipples or studs 4.
The carbon anode 2 is fixedly connected to the nipples 4 ~ by means of a cast connection 7 (cast iron) as shown in Figure 2.
- 10 Over the cast connection 7 and around the lower part of the nipp]es is provided a protecting ring 6 made of carbonaceous - paste. This is, as previously mentioned, made by at first placing a protecting collar 5 around the nipples 4 and thereafter filling up the empty space between the collar and the nipple.
, In Figure ~ is shown an example of a pro~ecting collar 8 ; of cardboard according to the invention. The collar is made of a piece of cardboard strip which is provided with a locking arrangement at its ends. The locking arrangement as here shown ~ consists of locking tongue 10 and a slit or slot 12.
s 20 The collar is shaped, as will be apparent ~rom Figuxe 3, by bending the collar so that the tongue may be lead through the ! slit 12. Cuts 11 at the inner end of the tongue provides barbs which prevent the tongue from being pulled out of the slit.
, :.
.
Figure ~ shows another locking arrangement. Here the cardboard strip 9 is at its ends provided with transverse cuts 13,14 stretching from the side edge to the centre line in opposition directions. The collar is shaped by endlng the .;,'; . S
.: ~
~ 3~20 cardboard strip and letting the two slots (cuts) 13,14 grip into one another.
The invention is not in any way limited to the above examples. Thus the collars may be made of cardboard strips where the ends are overlapping one another and are fixed by means of gluing, a locking pln or the like.
'~
`; '. ' .` `
',; ' ~ ,"
'"`'"'.'.;''"",;''
Claims (7)
1. A protective collar for use with an anode hanger for supporting an anode in an electrolytic cell for the production of aluminium by electrolysis, the anode hanger comprising a bar from which stubs protrude, the stubs being connected to the anode by means of cast iron connections, a protecting ring of carbonaceous paste being formed by pouring the paste within collars to form a cover over the cast iron and around the lower part of the stub, characterised in that each collar is made of cardboard.
2. A protecting collar as claimed in claim 1, characterised in that the cardboard is brown paste board.
3. A protecting collar according to any one of claims 1 and 2, characterised in that the collar is made of a strip of cardboard and in that the ends of the cardboard strip are attached to one another by means of a connecting arrangement.
4. A protecting collar according to claim 3, characterised in that the connecting arrangement comprises a locking tongue and a slot.
5. A protecting collar according to claim 3, characterised in that the connecting arrangement comprises two cuts, one at each end of the strip.
6. A protecting collar according to claim 3, characterised in that the ends of the strip overlap and are glued to one another.
7. A protecting collar according to claim 3, characterised in that the ends of the strip overlap and are attached to one another by means of a locking pin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO880099 | 1988-01-12 | ||
| NO880099A NO163141C (en) | 1988-01-12 | 1988-01-12 | CARBON ANODES PROTECTION CRAFTS. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1330320C true CA1330320C (en) | 1994-06-21 |
Family
ID=19890551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 587536 Expired - Fee Related CA1330320C (en) | 1988-01-12 | 1989-01-05 | Collars for the protection of anode hangers in aluminium electrolysis cells |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0324632B1 (en) |
| AU (1) | AU609567B2 (en) |
| BR (1) | BR8900109A (en) |
| CA (1) | CA1330320C (en) |
| DE (1) | DE68901461D1 (en) |
| ES (1) | ES2031685T3 (en) |
| IS (1) | IS3427A7 (en) |
| NO (1) | NO163141C (en) |
| NZ (1) | NZ227574A (en) |
| RU (1) | RU1838453C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2006419A1 (en) * | 2007-06-22 | 2008-12-24 | Sgl Carbon Ag | Reduced voltage drop anode assembly for aluminium electrolysis cell |
| CN102534672A (en) * | 2010-12-09 | 2012-07-04 | 贵阳铝镁设计研究院有限公司 | Positive electrode guide rod for electrolytic aluminum |
| FR2970979A1 (en) * | 2011-01-28 | 2012-08-03 | Rio Tinto Alcan Int Ltd | ANODE MANUFACTURING METHOD |
| RU2666622C1 (en) * | 2017-05-22 | 2018-09-11 | Владимир Григорьевич Гончаров | Motorized bicycle transmission (variants) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH321592A (en) * | 1954-12-07 | 1957-05-15 | Aluminium Ind Ag | Burnt carbon anode for aluminum electrolytic furnaces |
| DE2547061B2 (en) * | 1975-10-21 | 1978-06-08 | Kaiser-Preussag Aluminium Gmbh & Co, Voerde, 4223 Voerde | Device for protecting power supply pins on anode carbons for the fused-salt electrolysis of aluminum |
| CH625560A5 (en) * | 1977-12-16 | 1981-09-30 | Alusuisse |
-
1988
- 1988-01-12 NO NO880099A patent/NO163141C/en unknown
- 1988-12-30 IS IS3427A patent/IS3427A7/en unknown
-
1989
- 1989-01-05 CA CA 587536 patent/CA1330320C/en not_active Expired - Fee Related
- 1989-01-10 NZ NZ22757489A patent/NZ227574A/en unknown
- 1989-01-11 RU SU894613336A patent/RU1838453C/en active
- 1989-01-11 BR BR8900109A patent/BR8900109A/en not_active Application Discontinuation
- 1989-01-12 AU AU28437/89A patent/AU609567B2/en not_active Ceased
- 1989-01-12 EP EP19890300289 patent/EP0324632B1/en not_active Expired
- 1989-01-12 DE DE8989300289T patent/DE68901461D1/en not_active Expired - Lifetime
- 1989-01-12 ES ES89300289T patent/ES2031685T3/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| NO163141C (en) | 1990-04-18 |
| DE68901461D1 (en) | 1992-06-17 |
| IS3427A7 (en) | 1989-07-13 |
| EP0324632A1 (en) | 1989-07-19 |
| RU1838453C (en) | 1993-08-30 |
| NO880099D0 (en) | 1988-01-12 |
| NO880099L (en) | 1989-07-13 |
| NZ227574A (en) | 1990-09-26 |
| NO163141B (en) | 1990-01-02 |
| AU609567B2 (en) | 1991-05-02 |
| AU2843789A (en) | 1989-07-13 |
| BR8900109A (en) | 1989-09-05 |
| EP0324632B1 (en) | 1992-05-13 |
| ES2031685T3 (en) | 1992-12-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |