EP0324632B1 - Collars for the protection of anode hangers in aluminium electrolysis cells - Google Patents
Collars for the protection of anode hangers in aluminium electrolysis cells Download PDFInfo
- Publication number
- EP0324632B1 EP0324632B1 EP19890300289 EP89300289A EP0324632B1 EP 0324632 B1 EP0324632 B1 EP 0324632B1 EP 19890300289 EP19890300289 EP 19890300289 EP 89300289 A EP89300289 A EP 89300289A EP 0324632 B1 EP0324632 B1 EP 0324632B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- anode
- collar
- protecting
- strip
- aluminium
- 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
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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
- C25C3/12—Anodes
- C25C3/125—Anodes based on carbon
Definitions
- the present invention relates to the securing of anodes, such as those used in the electrolytic production of aluminium, to anode hangers. More especially, it relates to the protecting collar used to form a mould around the stubs of the anode hanger which are connected to the anode by cast iron connections. A protecting cover of carbonaceous paste is formed by pouring the paste into the gap formed between the collar and the stub.
- Aluminium is mostly produced by electrolysis of aluminium oxide dissolved is a cryolite bath.
- the electrolysis cells enabling this consist of a steel shell with an inner carbon lining. Insulation is provided between the steel and the carbon and conducting rods are incorporated into the carbon lining at the bottom of the cell to provide a cathode.
- One or more carbon anodes are provided above the cathode and are partly submerged in the cryolite bath. The carbon anodes are manufactured by mixing petroleum coke and pitch, forming the mixture into blocks, complete with sockets for electrical connection, and subsequently baking them.
- cryolite is kept in its melted condition at a temperature close to the solidification temperature.
- the most common temperatures for these cells are between 930 and 980° C.
- the aluminium produced descends to the bottom of the cell and is deposited on the carbon lining to form a cathode of molten aluminium.
- 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.
- 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 is one anode exchanged every day.
- 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 an anode bar down through the carbon bodies.
- the anode hangers are releasebly fixed to an overhanging anode bar by means of a clamping device. As the carbon anodes are gradually consumed and as aluminium metal is removed from the cells, 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 cathode.
- the current required for the electrolysis cell lies between 100 000 and 300 000 amps.
- Electric current connections and bus bars are therefore made of industrial metals with good electric conductivity i.e. usually pure copper or aluminium.
- this part of the anode hanger is made of material which is resistant to the high temperature, i.e. usually steel.
- An anode hanger consists of aluminium or copper rods welded or bolted to steel stubs. The stubs are then positioned in the pre-formed sockets of the anodes and molten cast iron is poured around the stubs to produce a strong connection which has low electrical resistance
- a protecting ring of carbonaceous paste is formed around the lower part of the stubs and over the cast iron connection. This is done by firstly placing a protecting collar around the nipples and subsequently filling up the spacing between the collar and the stubs with the carbonaceous paste. The protecting ring of carbonaceous paste is finally hardened approximately 24 hours after 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 would be liable to cause dissolution of the iron and steel which in turn may result in the stubs and cast iron becoming corroded such that the anode falls off the stubs.
- the protecting collars which have hitherto been employed have, due to the high temperature, been made of aluminium material (see e.g. DE-B-2547061). These aluminium collars have however been expensive to manufacture and to use. It is especially expensive to remove the aluminium material before the remains of the carbon anodes are processed for reuse.
- an anode hanger for supporting an anode in an electrolytic cell for the production of aluminium by electrolysis, comprises a bar from which stubs protrude, the stubs being connected to the anode by means of cast iron connection, a protecting cover 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 (5,8,9) is made of cardboard.
- the collar is preferably made of brown past board and may be in the form of a strip with some connecting arrangements provided at either end of the strip.
- Fig. 1 shows an anode hanger 1 supporting a so-called prebaked carbon anode 2 which is used in cells producing aluminium by electrolysis.
- the anode hanger 1 comprises an anode rod 3, of aluminium, and a cross member 15 of steel which is provided with three downwardly protruding steel stubs 4.
- the carbon anode 2 is fixedly connected to the stubs 4 by pouring cast iron 7 into the gap formed between the stub and the anode as shown in Fig. 2. Over the cast iron joint 7 and around the lower part of the stub 4 is provided a protecting ring made of carbonaceous paste 6.
- FIG. 3 is shown an example of a protecting collar 8 of cardboard according to the invention.
- the invention is made of a cardboard stip 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 cut 12.
- the collar is formed, as will be apparent from Fig. 3, by bending the collar so that the tongue may be led through the slit 12. Cuts 11 at the inner end of the tongue provide barbs which prevent the tongue from being pulled out of the slit.
- Fig. 4 shows another locking arrangement.
- the cardboard strip 9 is provided with transverse cuts 13,14 at its ends stretching from the side edge to the centre line in opposite directions.
- the collar is formed by bending the cardboard strip and letting the two slots (cuts) 12,14 grip into one another.
- the collars may be made of cardboard strips where the ends are overlapping one another and are fixed by means of gluing, locking pin or the like.
Description
- The present invention relates to the securing of anodes, such as those used in the electrolytic production of aluminium, to anode hangers. More especially, it relates to the protecting collar used to form a mould around the stubs of the anode hanger which are connected to the anode by cast iron connections. A protecting cover of carbonaceous paste is formed by pouring the paste into the gap formed between the collar and the stub.
- Aluminium is mostly produced by electrolysis of aluminium oxide dissolved is a cryolite bath. The electrolysis cells enabling this consist of a steel shell with an inner carbon lining. Insulation is provided between the steel and the carbon and conducting rods are incorporated into the carbon lining at the bottom of the cell to provide a cathode. One or more carbon anodes are provided above the cathode and are partly submerged in the cryolite bath. The carbon anodes are manufactured by mixing petroleum coke and pitch, forming the mixture into blocks, complete with sockets for electrical connection, and subsequently baking them.
- Electrical connections are provided to the top and the bottom of the cells, and the cryolite is kept in its melted condition at a temperature close to the solidification temperature. The most common temperatures for these cells are between 930 and 980° C.
- The aluminium produced descends to the bottom of the cell and is deposited on the carbon lining to form a cathode of molten aluminium. 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.
- 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 is one anode exchanged every day.
- 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 an anode bar down through the carbon bodies. The anode hangers are releasebly fixed to an overhanging anode bar by means of a clamping device. As the carbon anodes are gradually consumed and as aluminium metal is removed from the cells, 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 cathode.
- The current required for the electrolysis cell lies between 100 000 and 300 000 amps.
- Electric current connections and bus bars are therefore made of industrial metals with good electric conductivity i.e. usually pure copper or aluminium.
- Since the lower part of the anode hangers is situated close to the cryolite bath which is of a high temperature, this part of the anode hanger is made of material which is resistant to the high temperature, i.e. usually steel.
- An anode hanger consists of aluminium or copper rods welded or bolted to steel stubs. The stubs are then positioned in the pre-formed sockets of the anodes and molten cast iron is poured around the stubs to produce a strong connection which has low electrical resistance
- A protecting ring of carbonaceous paste is formed around the lower part of the stubs and over the cast iron connection. This is done by firstly placing a protecting collar around the nipples and subsequently filling up the spacing between the collar and the stubs with the carbonaceous paste. The protecting ring of carbonaceous paste is finally hardened approximately 24 hours after 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 would be liable to cause dissolution of the iron and steel which in turn may result in the stubs and cast iron becoming corroded such that the anode falls off the stubs.
- The protecting collars which have hitherto been employed have, due to the high temperature, been made of aluminium material (see e.g. DE-B-2547061). These aluminium collars have however been expensive to manufacture and to use. It is especially expensive to remove the aluminium material before the remains of the carbon anodes are processed for reuse.
- In accordance with the present invention an anode hanger for supporting an anode in an electrolytic cell for the production of aluminium by electrolysis, comprises a bar from which stubs protrude, the stubs being connected to the anode by means of cast iron connection, a protecting cover 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 (5,8,9) is made of cardboard.
- Hereby large savings may be achieved by reduced manufacturing costs. Further, the problem related to the cleaning of the anode hangers is avoided since the card board collar burns away during the electrolysis process due to the high temperature, but after the carbonaceous paste has hardened.
- The collar is preferably made of brown past board and may be in the form of a strip with some connecting arrangements provided at either end of the strip.
- The invention will now be further described by way of examples and with reference to the accompaning drawings in which:
- Fig. 1 shows an anode hanger onto which is mounted a carbon anode,
- Fig. 2 shows an enlarged section of the connection between a stub and the carbon anode shown in Fig. 1,
- Fig. 3 shows an example of a card board collar according to the invention, and
- Fig. 4 shows another example of a card board collar according to the invention.
- Fig. 1 shows an
anode hanger 1 supporting a so-called prebakedcarbon anode 2 which is used in cells producing aluminium by electrolysis. - The
anode hanger 1 comprises ananode rod 3, of aluminium, and across member 15 of steel which is provided with three downwardly protrudingsteel stubs 4. - The
carbon anode 2 is fixedly connected to thestubs 4 by pouringcast iron 7 into the gap formed between the stub and the anode as shown in Fig. 2. Over thecast iron joint 7 and around the lower part of thestub 4 is provided a protecting ring made ofcarbonaceous paste 6. - This, as previously mentioned, is made by at first placing a protecting
collar 5 around the stub and thereafter filling up the empty space between thecollar 5 and thestub 4. - In Fig. 3 is shown an example of a protecting
collar 8 of cardboard according to the invention. The invention is made of a cardboard stip which is provided with a locking arrangement at its ends. The locking arrangement as here shown consists of lockingtongue 10 and a slit or cut 12. - The collar is formed, as will be apparent from Fig. 3, by bending the collar so that the tongue may be led through the
slit 12.Cuts 11 at the inner end of the tongue provide barbs which prevent the tongue from being pulled out of the slit. - Fig. 4 shows another locking arrangement. Here the
cardboard strip 9 is provided withtransverse cuts - 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, locking pin or the like.
Claims (7)
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 (2)
Publication Number | Publication Date |
---|---|
EP0324632A1 EP0324632A1 (en) | 1989-07-19 |
EP0324632B1 true EP0324632B1 (en) | 1992-05-13 |
Family
ID=19890551
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19890300289 Expired EP0324632B1 (en) | 1988-01-12 | 1989-01-12 | 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 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
- 1989-01-12 AU AU28437/89A patent/AU609567B2/en not_active Ceased
Also Published As
Publication number | Publication date |
---|---|
BR8900109A (en) | 1989-09-05 |
RU1838453C (en) | 1993-08-30 |
NO163141C (en) | 1990-04-18 |
NO880099D0 (en) | 1988-01-12 |
IS3427A7 (en) | 1989-07-13 |
CA1330320C (en) | 1994-06-21 |
EP0324632A1 (en) | 1989-07-19 |
NZ227574A (en) | 1990-09-26 |
ES2031685T3 (en) | 1992-12-16 |
AU2843789A (en) | 1989-07-13 |
DE68901461D1 (en) | 1992-06-17 |
NO163141B (en) | 1990-01-02 |
NO880099L (en) | 1989-07-13 |
AU609567B2 (en) | 1991-05-02 |
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