CA2470753A1 - Graphitized cathode blocks - Google Patents
Graphitized cathode blocks Download PDFInfo
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- CA2470753A1 CA2470753A1 CA002470753A CA2470753A CA2470753A1 CA 2470753 A1 CA2470753 A1 CA 2470753A1 CA 002470753 A CA002470753 A CA 002470753A CA 2470753 A CA2470753 A CA 2470753A CA 2470753 A1 CA2470753 A1 CA 2470753A1
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- Prior art keywords
- cathode block
- parts
- graphitized
- cathode
- blocks
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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
- C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
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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)
Abstract
Disclosed are graphitized cathode blocks for producing aluminum by electrolytically reducing aluminum oxide in a molten cryolite bath. The electrical resistance of the inventive cathode blocks has a V-shaped profile across the length of the cathode blocks, increases towards the ends, and has a place of discontinuity in the middle thereof. Also disclosed are a method for the production of said cathode blocks and the use thereof for producing aluminum.
Description
SGL CARBON AG
Graphitized cathode blocks The invention relates to graphitized cathode blocks, a process for producing them and their use, in particular for the electrolytic production of aluminum.
In the electrolytic production of aluminum by the Hall-Heroult process, use is made of electrolysis cells which have a bottom which is made up of ~ plurality of blocks and acts as cathode. The electrolyte is a melt comprising mainly a solution of aluminum oxide in cryolite. The working temperature is, for example, about 1 000 °C. The electrolytically generated molten aluminum is deposited on the bottom of the cell under a layer of the electrolyte. The cells are surrounded by a metallic housing (preferably steel) lined with high-temperature-resistant material.
Due to the chemical resistance and thermal stability required, the material of choice for the cathode blocks is preferably carbon which may have been partially or completely graphitized by means of thermal treatment.
Such cathode blocks are produced by mixing pitches, cokes, anthracite and/or graphite in selected particle sizes or particle size distributions for the solids and shaping, firing and, if appropriate, (partially) graphi tizing the mixtures. Firing (carbonization) is usually carried out at temperatures of about 1 200 °C, and the graphitization is usually carried out at temperatures above 2 400 °C.
While graphitized cathodes are preferred because of their higher electrical conductivity, they suffer from increased corrosion during operation, corresponding to a mean annual decrease in their thickness of up to 80 mm.
This corrosion is not distributed uniformly over the length of the cathode blocks (corresponding to the width of the cell) , but the surface of the cathode blocks is changed to a W-shaped profile. Due to the nonuniform removal of material, the useful life of the cathode blocks is limited by the areas having the greatest removal of material.
One possible way of making the removal of material more uniform over the length of the cathode block and thus increasing the useful life is to configure the cathode blocks so that their electrical resistance varies over the length in such a way that the current density (and thus the corrosion) is uniform over their length or at least displays a very small deviation from its mean over the length.
One solution is described in DE 20 61 263, in which composite cathodes are made up of either a plurality of carbon blocks which have different electrical conduc-tivities and are arranged so that a uniform or approxi-mately uniform current distribution results, or of carbon blocks whose electrical resistances increase continuously in the direction of the cathodic terminals. The number of carbon blocks and their electrical resistance depends in each case on the size and type of the cell and have to be calculated afresh for each case. Cathode blocks made up of a plurality of individual carbon blocks are compli-cated to construct; the joins also have to be sealed well in order to prevent the liquid aluminum flowing out at the joins.
Graphitized cathode blocks The invention relates to graphitized cathode blocks, a process for producing them and their use, in particular for the electrolytic production of aluminum.
In the electrolytic production of aluminum by the Hall-Heroult process, use is made of electrolysis cells which have a bottom which is made up of ~ plurality of blocks and acts as cathode. The electrolyte is a melt comprising mainly a solution of aluminum oxide in cryolite. The working temperature is, for example, about 1 000 °C. The electrolytically generated molten aluminum is deposited on the bottom of the cell under a layer of the electrolyte. The cells are surrounded by a metallic housing (preferably steel) lined with high-temperature-resistant material.
Due to the chemical resistance and thermal stability required, the material of choice for the cathode blocks is preferably carbon which may have been partially or completely graphitized by means of thermal treatment.
Such cathode blocks are produced by mixing pitches, cokes, anthracite and/or graphite in selected particle sizes or particle size distributions for the solids and shaping, firing and, if appropriate, (partially) graphi tizing the mixtures. Firing (carbonization) is usually carried out at temperatures of about 1 200 °C, and the graphitization is usually carried out at temperatures above 2 400 °C.
While graphitized cathodes are preferred because of their higher electrical conductivity, they suffer from increased corrosion during operation, corresponding to a mean annual decrease in their thickness of up to 80 mm.
This corrosion is not distributed uniformly over the length of the cathode blocks (corresponding to the width of the cell) , but the surface of the cathode blocks is changed to a W-shaped profile. Due to the nonuniform removal of material, the useful life of the cathode blocks is limited by the areas having the greatest removal of material.
One possible way of making the removal of material more uniform over the length of the cathode block and thus increasing the useful life is to configure the cathode blocks so that their electrical resistance varies over the length in such a way that the current density (and thus the corrosion) is uniform over their length or at least displays a very small deviation from its mean over the length.
One solution is described in DE 20 61 263, in which composite cathodes are made up of either a plurality of carbon blocks which have different electrical conduc-tivities and are arranged so that a uniform or approxi-mately uniform current distribution results, or of carbon blocks whose electrical resistances increase continuously in the direction of the cathodic terminals. The number of carbon blocks and their electrical resistance depends in each case on the size and type of the cell and have to be calculated afresh for each case. Cathode blocks made up of a plurality of individual carbon blocks are compli-cated to construct; the joins also have to be sealed well in order to prevent the liquid aluminum flowing out at the joins.
In WO 00/46426, a graphite cathode is described consisting of a single block which has an electrical conductivity which is varied over its length, with the conductivity being lower at the ends of the block than in the middle. This nonuniform distribution of electrical conductivity is achieved by bringing the end zones to a temperature of from 2 200 to 2 500 °C during graphitization, while the middle zone is exposed to a temperature of from 2 700 to 3 000 °C. This different heat treatment can be achieved in two ways according to these teachings: on the one hand, heat loss in the graphitization furnace can be limited differently, or heat sinks can be provided in the vicinity of the end zones so as to increase the heat loss. In the case of a transverse graphitization, the density of the thermally insulating bed is altered so that the heat loss over the length of the cathodes becomes nonuniform and the desired temperatures are obtained as a result. In the case of longitudinal graphitization, too, heat loss in the vicinity of the ends can be increased by different configuration of the thermally insulating bed, or bodies which carry away the heat, preferably graphite bodies, are installed for this purpose in their vicinity so as to produce greater outward heat flow to the furnace wall.
According to another method, the difference in heat treatment can be achieved by local changes in the current density, with the result of different heat evolution.
This change in the current density can, according to the teachings, be achieved by different resistances of the conductive bed between two cathodes in an Acheson furnace (transverse graphitization); no such solution is indica-ted for a longitudinal graphitization process.
According to another method, the difference in heat treatment can be achieved by local changes in the current density, with the result of different heat evolution.
This change in the current density can, according to the teachings, be achieved by different resistances of the conductive bed between two cathodes in an Acheson furnace (transverse graphitization); no such solution is indica-ted for a longitudinal graphitization process.
These known methods have considerable disadvantages for industrial use. A difference of 500 °C in the desired graphitization temperatures in the middle and at the ends of the cathodes cannot be achieved by means of heat sinks alone. The required difference in heat conduction to the outside results in a considerable energy loss which significantly increases the cost of manufacture. The higher heat loss toward the side of the furnace also means a higher thermal load which makes the construction of the furnace more expensive or reduces its life.
Finally, an inhomogeneity in the thermally insulating bed or the conductive bed is not very practical, since the bed material would have to be introduced in a plurality of steps and would have to be classified again according to its thermal conduction or electrical conductivity after the furnace cycle is concluded and the cathodes are removed.
It is therefore an object of the present invention to provide graphitized cathode blocks with an electrical conductivity varying along their length.
Graphitization of cathode blocks by the longitudinal graphitization process results in an electrical transi-tion at the joins between the individual cathode blocks themselves or between the blocks and electrically conduc-tive connecting elements located between them. This electrical transition has a resistance higher than the resistance in the interior of the individual cathode blocks or the connecting element. This increased resis-tance leads to increased generation of heat and thus to a higher temperature, i.e. to an acceleration of the graphitization reaction. The electrical resistance at the ends of the cathode blocks is therefore usually lower than that in the middle of the cathode blocks in the case of longitudinal graphitization. This distribution of the resistance or the electrical conductivity over the length of the cathode block is precisely the opposite of what is desired.
It has now been found that cathode blocks having the desired distribution can be produced in a simple way by i ~~~~,_g-_._the tee.-._~escrib~d.. oath,Qde .bloc-ks. ap.art_ _i n_ h~..__,~
middle and rejoining them in the opposite direction. This gives a profile of the electrical resistance having the shape of a V whose legs (arms) are rounded.
The presynt invention therefore provides graphitized cathode b~~cks for the production of. aluminum by electrolytic'~~eduction of aluminum oxide in a bath of molten cryolite,'..wherein the cathode blocks are composed of at least two parts and have a V-shaped profile of their electrical resistance over their length, with the resistance in the middle of the cathode blocks displaying a discontinuity and increasing monotonically toward the ends so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1,05:1.
The cathode blocks are preferably composed of at least two parts whose electrical resistance increases mono-tonically over their length so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.15:1. This ratio is particularly preferably 1.3:1.
The invention is illustrated by the drawings: In the drawings:
Fig. 1 shows the variation in the specific electrical resistance p over the length of. theca~_h~~
are rounded.
The present invention therefore provides graphitized cathode blocks for the production of aluminum by electrolytic reduction of aluminum oxide in a bath of molten cryolite, wherein the cathode blocks are composed of two parts and have a V-shaped profile of their electrical resistance over their length, with the resistance in the middle of the cathode blocks displaying a discontinuity and increasing monotonically toward the ends so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.05:1.
The cathode blocks are preferably composed of two parts whose electrical resistance increases monotonically over their length so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.15:1. This ratio is particularly preferably 1.3:1.
AMENDED SHEET
cutting apart and rejoining them in the opposite direction. This gives a profile of the electrical resistance having the shape of a V whose legs (arms) ." r The invention is illustrated by the drawings: In the drawings:
Fig. 1 shows the variation in the specific electrical resistance p over the length of the cathode block, as is obtained in longitudinal graphitization with a high transition resistance between the individual cathode blocks, shown in a side view of a cathode block, Fig. 2 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with a joining layer of tamping composition being introduced in the middle, Fig. 3 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with an adhesive join in the middle connecting the two parts, and AMENDED SHEET
w _- ...~ .._..~.. b 1 o c k~~ ".° ~a ~ ...".:i.~...-.~a.,i..ne ~ . . i ~ - ~ o n g i t a a~i n~a 1 ~g r a p tization with a high transition r~"sistance between the individual cathode blor~ksr, shown in a side view of a cathode bloc.~:;'~,~
Fig. 2 shows a side view of adrlcathode block which has been cut apart in i~e middle and put together the other way und, with a joining layer of ramming past,,~''~ being introduced in the middle, Fig. 3 shows,~t°~side view of a cathode block which has beef cut apart in the middle and put together a other way around, with an adhesive join in / thew_middle connecting the twos-s;---~~
_.,__~_,..__.._____. _ _.....~....~.--..---°.
Fig. 4 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with the tw, o parts merely being butted together.
In detail, fig. 1 shows the variation of the specific electrical resistance p, calculated as (Ra/~, where R is the electrical resistance of a cuboidal test specimen, a is its cross-sectional area and leis its length, depicted in the interior of the side view of a cathode block 4 over the length of the cathode block. The ends of the block as is obtained in longitudinal graphitization are denoted by A. The cathode block is cut apart along the line BB, with the end faces at A being denoted by 4-1 and the parted surface along the line BB in the side view being designated as 4-2. The parted cathode block is then joined together as shown in fig. 2 to 4 so that the ends A or the end faces 4-1 are located in the middle of the composite cathode block.
_ 7 _ Fig. 2 shows an embodiment in which a layer of the ramming paste 5 is located between the two end faces 4-1 at the ends A which are now located in the middle; this ramming paste also serves to seal the contact areas between the individual cathode blocks at the bottom of the electrolysis cell. Suitable ramming pastes for this purpose are compositions based on anthracite and graphite and having a density of about 1 700 kg/m3,~ e.g. BST 17/1 from SGL Carbon AG.
The previously internal areas 4-2 have now become exterior faces. The variation of the specific electrical resistance p is now such that the lowest value is in the middle of the cathode block and the specific electrical resistance now increases symmetrically from the middle point to the ends. Conversely, the electrical conduc-tivity now displays a peak in the middle of the cathode block and decreases towards to the ends.
Fig. 3 depicts a further preferred embodiment in which the two half blocks are each joined together at the ends A by a layer of an adhesive 6 having the required thermal stability.
Suitable adhesives are cold-curing resins such as BVK6 from SGL Carbon AG.
Finally, fig. 4 shows an embodiment in which a bonding layer or intermediate layer has been omitted and the two half blocks have merely been butted together at their ends A. The required pressure is in this case produced by the thermal expansion of the half blocks which are pressed together on heating after they have been installed in contact with one another in the electrolysis cells. It has been found that the pressure is sufficient _ g _ to ensure a reliable and leak-free join between the two half blocks provided that the end faces before cutting were sufficiently planar.
The graphitized cathode blocks of the invention display more uniform corrosion over the length of the cathode and therefore a significantly increased life compared to the conventional blocks having a homogeneous distribution of the electrical conductivity when used in the production of aluminum by electrolytic reduction of aluminum oxide in a bath of molten cryolite.
Finally, an inhomogeneity in the thermally insulating bed or the conductive bed is not very practical, since the bed material would have to be introduced in a plurality of steps and would have to be classified again according to its thermal conduction or electrical conductivity after the furnace cycle is concluded and the cathodes are removed.
It is therefore an object of the present invention to provide graphitized cathode blocks with an electrical conductivity varying along their length.
Graphitization of cathode blocks by the longitudinal graphitization process results in an electrical transi-tion at the joins between the individual cathode blocks themselves or between the blocks and electrically conduc-tive connecting elements located between them. This electrical transition has a resistance higher than the resistance in the interior of the individual cathode blocks or the connecting element. This increased resis-tance leads to increased generation of heat and thus to a higher temperature, i.e. to an acceleration of the graphitization reaction. The electrical resistance at the ends of the cathode blocks is therefore usually lower than that in the middle of the cathode blocks in the case of longitudinal graphitization. This distribution of the resistance or the electrical conductivity over the length of the cathode block is precisely the opposite of what is desired.
It has now been found that cathode blocks having the desired distribution can be produced in a simple way by i ~~~~,_g-_._the tee.-._~escrib~d.. oath,Qde .bloc-ks. ap.art_ _i n_ h~..__,~
middle and rejoining them in the opposite direction. This gives a profile of the electrical resistance having the shape of a V whose legs (arms) are rounded.
The presynt invention therefore provides graphitized cathode b~~cks for the production of. aluminum by electrolytic'~~eduction of aluminum oxide in a bath of molten cryolite,'..wherein the cathode blocks are composed of at least two parts and have a V-shaped profile of their electrical resistance over their length, with the resistance in the middle of the cathode blocks displaying a discontinuity and increasing monotonically toward the ends so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1,05:1.
The cathode blocks are preferably composed of at least two parts whose electrical resistance increases mono-tonically over their length so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.15:1. This ratio is particularly preferably 1.3:1.
The invention is illustrated by the drawings: In the drawings:
Fig. 1 shows the variation in the specific electrical resistance p over the length of. theca~_h~~
are rounded.
The present invention therefore provides graphitized cathode blocks for the production of aluminum by electrolytic reduction of aluminum oxide in a bath of molten cryolite, wherein the cathode blocks are composed of two parts and have a V-shaped profile of their electrical resistance over their length, with the resistance in the middle of the cathode blocks displaying a discontinuity and increasing monotonically toward the ends so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.05:1.
The cathode blocks are preferably composed of two parts whose electrical resistance increases monotonically over their length so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.15:1. This ratio is particularly preferably 1.3:1.
AMENDED SHEET
cutting apart and rejoining them in the opposite direction. This gives a profile of the electrical resistance having the shape of a V whose legs (arms) ." r The invention is illustrated by the drawings: In the drawings:
Fig. 1 shows the variation in the specific electrical resistance p over the length of the cathode block, as is obtained in longitudinal graphitization with a high transition resistance between the individual cathode blocks, shown in a side view of a cathode block, Fig. 2 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with a joining layer of tamping composition being introduced in the middle, Fig. 3 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with an adhesive join in the middle connecting the two parts, and AMENDED SHEET
w _- ...~ .._..~.. b 1 o c k~~ ".° ~a ~ ...".:i.~...-.~a.,i..ne ~ . . i ~ - ~ o n g i t a a~i n~a 1 ~g r a p tization with a high transition r~"sistance between the individual cathode blor~ksr, shown in a side view of a cathode bloc.~:;'~,~
Fig. 2 shows a side view of adrlcathode block which has been cut apart in i~e middle and put together the other way und, with a joining layer of ramming past,,~''~ being introduced in the middle, Fig. 3 shows,~t°~side view of a cathode block which has beef cut apart in the middle and put together a other way around, with an adhesive join in / thew_middle connecting the twos-s;---~~
_.,__~_,..__.._____. _ _.....~....~.--..---°.
Fig. 4 shows a side view of a cathode block which has been cut apart in the middle and put together the other way around, with the tw, o parts merely being butted together.
In detail, fig. 1 shows the variation of the specific electrical resistance p, calculated as (Ra/~, where R is the electrical resistance of a cuboidal test specimen, a is its cross-sectional area and leis its length, depicted in the interior of the side view of a cathode block 4 over the length of the cathode block. The ends of the block as is obtained in longitudinal graphitization are denoted by A. The cathode block is cut apart along the line BB, with the end faces at A being denoted by 4-1 and the parted surface along the line BB in the side view being designated as 4-2. The parted cathode block is then joined together as shown in fig. 2 to 4 so that the ends A or the end faces 4-1 are located in the middle of the composite cathode block.
_ 7 _ Fig. 2 shows an embodiment in which a layer of the ramming paste 5 is located between the two end faces 4-1 at the ends A which are now located in the middle; this ramming paste also serves to seal the contact areas between the individual cathode blocks at the bottom of the electrolysis cell. Suitable ramming pastes for this purpose are compositions based on anthracite and graphite and having a density of about 1 700 kg/m3,~ e.g. BST 17/1 from SGL Carbon AG.
The previously internal areas 4-2 have now become exterior faces. The variation of the specific electrical resistance p is now such that the lowest value is in the middle of the cathode block and the specific electrical resistance now increases symmetrically from the middle point to the ends. Conversely, the electrical conduc-tivity now displays a peak in the middle of the cathode block and decreases towards to the ends.
Fig. 3 depicts a further preferred embodiment in which the two half blocks are each joined together at the ends A by a layer of an adhesive 6 having the required thermal stability.
Suitable adhesives are cold-curing resins such as BVK6 from SGL Carbon AG.
Finally, fig. 4 shows an embodiment in which a bonding layer or intermediate layer has been omitted and the two half blocks have merely been butted together at their ends A. The required pressure is in this case produced by the thermal expansion of the half blocks which are pressed together on heating after they have been installed in contact with one another in the electrolysis cells. It has been found that the pressure is sufficient _ g _ to ensure a reliable and leak-free join between the two half blocks provided that the end faces before cutting were sufficiently planar.
The graphitized cathode blocks of the invention display more uniform corrosion over the length of the cathode and therefore a significantly increased life compared to the conventional blocks having a homogeneous distribution of the electrical conductivity when used in the production of aluminum by electrolytic reduction of aluminum oxide in a bath of molten cryolite.
Claims (9)
1. A graphitized cathode block for the production of aluminum by electrolytic reduction of aluminum oxide in a bath of molten cryolite, wherein the cathode block is composed of two parts and has a V-shaped profile of its electrical resistance over its length, with the resistance in the middle of the cathode block displaying a discontinuity and increasing monotonically toward the ends so that the ratio of the resistance at the ends of the parts to that in the middle is at least 1.05:1.
2. A graphitized cathode block as claimed in claim 1, wherein the cathode block is composed of two parts and the contact areas of the parts are held together by mechanical pressing.
3. A graphitized cathode block as claimed in claim 1, wherein the cathode block is composed of two parts and the contact areas of the parts are joined by means of a tamping composition.
4. A graphitized cathode block as claimed in claim 1, wherein the cathode block is composed of two parts and the contact areas of the parts are adhesively bonded.
Claims
Claims
5. A process for producing graphitized cathode blocks as claimed in claim 1, which comprises cutting a graphitized cathode block whose electrical conduc-tivity over the length corresponds to the profile of a flat U in its middle and putting it together again with the original external faces directed inward.
6. The process as claimed in claim 5, wherein the com-posite cathode block is held together by mechanical pressure in the electrolysis cell.
7. The process as claimed in claim 5, wherein the composite cathode block is held together by the thermal expansion in the electrolysis cell.
8. The process as claimed in claim 5, wherein the composite cathode block is joined in the middle by means of a ramming paste.
9. The process as claimed in claim 5, wherein the composite cathode block is adhesively bonded in the middle.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10164008.0 | 2001-12-28 | ||
| DE2001164008 DE10164008C1 (en) | 2001-12-28 | 2001-12-28 | Graphitized cathode block, used for producing aluminum by electrolytically reducing aluminum oxide in a bath of molten cryolite, is composed of two parts and has a V-shaped profile of its electrical resistance over its length |
| PCT/EP2002/014548 WO2003056068A2 (en) | 2001-12-28 | 2002-12-19 | Graphitized cathode blocks |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2470753A1 true CA2470753A1 (en) | 2003-07-10 |
Family
ID=7710902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002470753A Abandoned CA2470753A1 (en) | 2001-12-28 | 2002-12-19 | Graphitized cathode blocks |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP1481115B1 (en) |
| AR (1) | AR037912A1 (en) |
| AU (1) | AU2002361174A1 (en) |
| BR (1) | BR0215323A (en) |
| CA (1) | CA2470753A1 (en) |
| DE (2) | DE10164008C1 (en) |
| PL (1) | PL201672B1 (en) |
| WO (1) | WO2003056068A2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102011076302A1 (en) | 2011-05-23 | 2013-01-03 | Sgl Carbon Se | Electrolysis cell and cathode with irregular surface profiling |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2728109A (en) * | 1952-06-06 | 1955-12-27 | Savoie Electrodes Refract | Method of making cathodic electrodes for electrolysis furnaces |
| US4194959A (en) * | 1977-11-23 | 1980-03-25 | Alcan Research And Development Limited | Electrolytic reduction cells |
| NO157462C (en) * | 1985-10-24 | 1988-03-23 | Hydro Aluminium As | LAMINATED CARBON CATHOD FOR CELLS-MELT-ELECTROLYTIC ALUMINUM PREPARATION. |
| US4795540A (en) * | 1987-05-19 | 1989-01-03 | Comalco Aluminum, Ltd. | Slotted cathode collector bar for electrolyte reduction cell |
| FR2789091B1 (en) * | 1999-02-02 | 2001-03-09 | Carbone Savoie | GRAPHITE CATHODE FOR ALUMINUM ELECTROLYSIS |
| EP1233083A1 (en) * | 2001-02-14 | 2002-08-21 | Alcan Technology & Management AG | Carbon bottom of electrolysis cell used in the production of aluminum |
-
2001
- 2001-12-28 DE DE2001164008 patent/DE10164008C1/en not_active Expired - Fee Related
-
2002
- 2002-12-18 AR ARP020104963 patent/AR037912A1/en unknown
- 2002-12-19 CA CA002470753A patent/CA2470753A1/en not_active Abandoned
- 2002-12-19 PL PL369969A patent/PL201672B1/en not_active IP Right Cessation
- 2002-12-19 EP EP02796687A patent/EP1481115B1/en not_active Expired - Fee Related
- 2002-12-19 WO PCT/EP2002/014548 patent/WO2003056068A2/en active IP Right Grant
- 2002-12-19 BR BR0215323-8A patent/BR0215323A/en not_active IP Right Cessation
- 2002-12-19 AU AU2002361174A patent/AU2002361174A1/en not_active Abandoned
- 2002-12-19 DE DE50205232T patent/DE50205232D1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP1481115B1 (en) | 2005-12-07 |
| WO2003056068A2 (en) | 2003-07-10 |
| BR0215323A (en) | 2004-10-19 |
| PL369969A1 (en) | 2005-05-02 |
| PL201672B1 (en) | 2009-04-30 |
| WO2003056068A3 (en) | 2004-09-30 |
| DE50205232D1 (en) | 2006-01-12 |
| AR037912A1 (en) | 2004-12-22 |
| DE10164008C1 (en) | 2003-04-30 |
| AU2002361174A1 (en) | 2003-07-15 |
| EP1481115A2 (en) | 2004-12-01 |
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| FZDE | Discontinued |