CA1148892A - Quenching anode effect by anode rocking - Google Patents
Quenching anode effect by anode rockingInfo
- Publication number
- CA1148892A CA1148892A CA000324700A CA324700A CA1148892A CA 1148892 A CA1148892 A CA 1148892A CA 000324700 A CA000324700 A CA 000324700A CA 324700 A CA324700 A CA 324700A CA 1148892 A CA1148892 A CA 1148892A
- Authority
- CA
- Canada
- Prior art keywords
- anode
- bath
- effect
- rocking
- quenching
- 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
Links
Landscapes
- Electrolytic Production Of Metals (AREA)
Abstract
ABSTRACT
A method of quenching anode effect when producing aluminium by electrolytic reduction, characterized in that the anode, when anode effect has started, is placed in an inclined position, so that the wearing surface forms an angle of up to 20 with the horizontal. This method is called anode rocking and has obvious advantages:
1) The surface of the bath remains at the same level. The bath will merely flow from the one end to the other. This can be advantageous for mixing of low and high alumina concentration in the bath.
2) The wearing face of the anode will be inclined, so that the gas and the gas film can more readily escape, 3) It is not necessary to make the cathode shells higher in order to contain the bath.
4) The energy consumption is kept down because the thermal insulation efficiency of the crust is not impaired by its being mixed with molten bath and alumina.
5) The loss of energy through molten bath flooding over the crust is avoided.
6) There is no spilling of bath onto the floor.
A method of quenching anode effect when producing aluminium by electrolytic reduction, characterized in that the anode, when anode effect has started, is placed in an inclined position, so that the wearing surface forms an angle of up to 20 with the horizontal. This method is called anode rocking and has obvious advantages:
1) The surface of the bath remains at the same level. The bath will merely flow from the one end to the other. This can be advantageous for mixing of low and high alumina concentration in the bath.
2) The wearing face of the anode will be inclined, so that the gas and the gas film can more readily escape, 3) It is not necessary to make the cathode shells higher in order to contain the bath.
4) The energy consumption is kept down because the thermal insulation efficiency of the crust is not impaired by its being mixed with molten bath and alumina.
5) The loss of energy through molten bath flooding over the crust is avoided.
6) There is no spilling of bath onto the floor.
Description
Quenchinq anode effect by anode_rockin~
This invention relates to a method of quenching anode effect during the production of aluminum by electrolytic smelting.
The invention is particularly suitable for the automatic operation of pots and potlines.
Aluminum is normally produced by the Hall-Heroult method which involves the use of an electrolytic cell operating in the tempera-ture range 950 - 980C, decomposing alumina dlssolved in a bath of molten cryolite. Normally, over 100 such cells, or pots, are connected in series.
The individual electrolytic cell consists of a flat vessel with low sides, built of steel plates. Inside this steel shell there is a refractory layer which surrounds a carbon lining. The carbon lining contains the molten bath, which consists of cryo-lite with various additives. The carbon walls of the vessel are usually covered with frozen bath which continues some way out along the bottom. Most of the carbon bottom is free of frozen bath and serves as the cathode. The entire bottom is covered with molten aluminum, extracted from the alumina, and this aluminium has a higher specific gravity than the molten bath.
The anode, which is made of carbon, is partly immersed in the bath which, as mentioned above, consists mainly of molten cryo-lite and dissolved aluminaO The distance between the bottom of the anode and the molten metal on the cathode is called the ACD
(anode-cathode distance) or the interpolar distance, and is in the region of 2-7 cm.
The bath can also contain other substances to influence the solubility of the alumina and the freezing point of the bath.
This subject is discussed in a number of publications, but, as will be understood, these additives are of no interest in connec-tion with the present invention. The bath around the anode is covered with a crust of frozen bath. On top of this crust the ~.
8~
alumina is laid so that it is pre-heated before being pushed down into the bath.
During normal operations, the electrolytic reduction process takes place with a voltage drop from anode to cathode of between 4 and 6 V, dependent upon the cell design chosen. At the beginning of the reduction process, the concentration of alumina in the bath can lie around G-8~. The electrolytic process decomposes the alumina. The metal thus extracted sinks down on to the cathode, whilst the oxygen is liberated on the underside of the anode. The anode is thus oxidized and is con-sumed, whilst at the same time the alumina content in the bath is reduced. When the alumina concentration in the bath falls below a certain critical value - about 2~ - depending upon the temperature of the bath and the current density of the anode etc., the steady electrolysis process is replaced by an anode e~fect. This reveals itself in the form of a sudden increase in the resistance of the electrolytic cell which, in the course of seconds, can increase tenfold. This increase in resistance is normally attributed to a layer of gas under the anode, see for example Norwegian patent No. 123318.
To indicate the presence of an anode effect, an electric incandescent lamp is connected across the cell. It lights up on anode effect because of the higher voltage. The normal practice is to endeavour to quench or terminate an anode effect as soon as possible, because it brings with it a number of disadvantages.
The sharp increase in resistance can result in a loss of energy in other pots in the series, thus disturbing operations. The extra energy resulting from this higher resistance causes the pot undergoing anode effect to heat excessively causing the electrolyte to evaporate with consequent large direct loss of bath vapours, mainly fluorides. This emission of fluorides to the atmosphere requires costly scrubbing.
If an anode effect is allowed to remain active too long, the operatlon of the pot is substantially disturbed and this requires i ~ , ~ . ~
extra efforts on the part of personnel to bring the pot back into normal operation, whilst at the same time output falls.
To quench anode effect, the alumina concentration in the bath under the anode must be raised. The earlier method of doing this was that the operator manually broke ~he crust around the anode, whereby the alumina which had been laid on top of the crust for pre-heating, fell down into the melt. The operator used a heavy iron implement to mix the alumina into the bath and then to rake under the anode with vigorous movements. Another method of quenching anode effect was to knock a hole in the crust and insert a wooden pole down into the bath under the anode. The gas liberated from the pole resulted in a powerful stirring of the bath, thus quenching the anode effec~. The pole has sub-sequently in a number of instances been replaced by an air lance, i.e. a tube which is used to blow compressed air down into the bath and thus to bxing about a particularly vigorous stirring under the anode.
These methods of quenching anode effect require heavy work in a hot and gas~filled atmosphere. A number o~ attempts have there-fore been made to mechanize and automate these operations.
British patent no. 853056 describes a method whereby an audio-frequency vibrator i~ used for quenching anode effect. How this procedure quenches anode effect is not explained. `
In US patent no. 2560854, a procedure is described for terminat-ing anode effect by slowly swinging the anode from a region in the electrolyte with low concentration of alumina to a region with a higher alumina concentration. It is clear that this method will mix alumina and bath and thus help to quench the anode effect, but it requires complicated and expensive equip-ment.
Norwegian patent no. 123318 discloses a method of quenching anode effect which is built on the principle that the entire anode is lowered ~o between 30 and 6 % of the normal interpolar distance, and then raised again. This lowering is started when the voltage drop across the cell exceeds 150 % of the normal working voltage, and the anode ls raised again under the control of a timing device incorporating a cam mechanism. Whilst the anode is in its lower position, an apparatus for feeding alumina to the bath is activated, so that an alumina concentration of 2-6 ~ in the bath is achieved. This procedure will doubtless reduce the amount of manual work involved in quenching anode effect, but it has nevertheless certain disadvantages. When the anode is lowered, the level of the ba-th rises because the anode must, of necessity, displace fluid. The pot shells have therefore to be somewhat higher than usual. As the bath rises, it will come into contact with the crust along the sides of the pot. This will, in time, result in a mixing of bath and alumina which solidifies forming a crust. This crust will have better heat conductivity than pure alumina and will thus iead to heat loss along the sides.
In those cases where bath overflows in connection with this so-called anode pumping, the heat content in the bath which flows out over the crust will be dissipated to the surroundings, and the spilt bath causes extra work.
In modern smelters, computers are used to control many of the pot operations. An important parameter in control strategy is the reference resistance of a pot. This is around 20 microohm and is defined as the pot voltage minus the decomposition voltage divided by the potline amperage.
In addition to the disadvantages inherent in NP 123318, there is also the increase in the reference vol~age, which means a higher consumption of energy in production.
The inventors have now found a method of quenching anode effect 3n whereby the above-mentioned difficultles are avoided. The principle of the method is that the anode is lowered at the one end whilst at the same time the other end is raised, when anode effect has occurred and is to be quenched. In other words, instead of lowering the entire anode, only a part of it is _ 4 -8~
lo~ered, whilst the opposite end is raised. The anode is thus rocked about an axis, which axis may lie either in the longi-tudinal direction of the anode or in the transverse direction.
This method is called anode rocking and has obvious advantages:
1) The surface of the bath remains at the same level. The bath will merely flow from the one end to the other. This can be advantageous for mixing of low and high alumina concentration in the bath. 2) The wearing face of the anode will be inclined, so that the gas and the gas film can more readily escape.
3) It is not necessary to make the cathode shells higher in order to contain the bath. 4) The energy consumption is kept down because the thermal insulation efficiency of the crust is not impaired by its being mixed with molten bath and alumina.
5) The loss of energy through molten bath flooding over the crust is avoided. 6) There is no spilling of bath on to the floor.
Thus, the present invention provides a method of quenching anode effect when producing aluminium by electrolytic reduction charac-terized by anode rocking whereby the anode, when anode effect has started, is placed in an inclined position so that its ~' wearing surface forms an angle of up to 20 degrees with the `
horizontal and the anode is ~lternately rocked about either its longitudinal or transverse axis and then allowed to rest in its inclined position until the anode effect is quenched, whereupon the anode is returned to its normal horizontal position.
It is obvious that the performance of anode rocking imposes certain requirements on the mechanical equipment, but the type of equipment in general use today in modern pots can usually be readily adapted, only minor additional installations being required.
The anode is usually suspended in jacks, which are operated by lifting motors at each end of the anode. These motors have to be operated independently of one another, only through impulses from a common control device.
~ 8~ ~
The working program for anode rocklng can be easily fitted into existing programs.
The work rhythm for a modern potroom prepared for the quenching of anode effect by anode rocking will comprise the usual operations in the usual sequence: alumina feed on to the crust, crust breaking outside anode effect and crust breaking durlng anode effect, followed by anode rocking.
Even if these operations are performed in all potlines, the routines will not be identical in the different plants.
On the basis of trials, the inventors have arrived at a prefer-red work method, but all methods are dependent on the apparatus and the operational characteristics of the method regarding time periods for anode rocking.
On the occurrence of anode effect, i.e. on exceeding a preset cell voltage (reference voltage), anode rocking is initiated by a control device, and lasts from 0-80 seconds whilst the anode is in an inclined positionO This is followed by a resting period of about 60 seconds to see whether the anode effect will reoccur. If it does not do so, the control device completes the order cycle for anode effect quenching by straightening up the anode and placing it in its normal position. Should, on the other hand, a new anode effect occur, the anode will be lowered about 10 mm whilst still ln the inclined position, but will be returned - 5a -to normal position after a short time, for example lo seconds, whereupon the order cycle will be terminated by straightening up the anode.
The times and durations stated here refer to given pot equipment.
It will be obvious that the invention can equally we].l be per-formed using other parameter values, with this reducing the scope of the invention.
During anode rocking, it has been shown that the lowest paxt of the anode carries a considerably higher current than normal, loo~ or more but, surprisingly enough, this has not proved to have any harmful effect. Weither has it been found that anode rocking has had any adverse mechanical consequences or operational com plications.
It is pointed out that the desired effect, the quenching of anode `
effect, is probably due to two aspects of anode rocking:
1) The bath is set in motion in a manner which will lead to the mixing in of bath with a higher alumina content under the anode.
This invention relates to a method of quenching anode effect during the production of aluminum by electrolytic smelting.
The invention is particularly suitable for the automatic operation of pots and potlines.
Aluminum is normally produced by the Hall-Heroult method which involves the use of an electrolytic cell operating in the tempera-ture range 950 - 980C, decomposing alumina dlssolved in a bath of molten cryolite. Normally, over 100 such cells, or pots, are connected in series.
The individual electrolytic cell consists of a flat vessel with low sides, built of steel plates. Inside this steel shell there is a refractory layer which surrounds a carbon lining. The carbon lining contains the molten bath, which consists of cryo-lite with various additives. The carbon walls of the vessel are usually covered with frozen bath which continues some way out along the bottom. Most of the carbon bottom is free of frozen bath and serves as the cathode. The entire bottom is covered with molten aluminum, extracted from the alumina, and this aluminium has a higher specific gravity than the molten bath.
The anode, which is made of carbon, is partly immersed in the bath which, as mentioned above, consists mainly of molten cryo-lite and dissolved aluminaO The distance between the bottom of the anode and the molten metal on the cathode is called the ACD
(anode-cathode distance) or the interpolar distance, and is in the region of 2-7 cm.
The bath can also contain other substances to influence the solubility of the alumina and the freezing point of the bath.
This subject is discussed in a number of publications, but, as will be understood, these additives are of no interest in connec-tion with the present invention. The bath around the anode is covered with a crust of frozen bath. On top of this crust the ~.
8~
alumina is laid so that it is pre-heated before being pushed down into the bath.
During normal operations, the electrolytic reduction process takes place with a voltage drop from anode to cathode of between 4 and 6 V, dependent upon the cell design chosen. At the beginning of the reduction process, the concentration of alumina in the bath can lie around G-8~. The electrolytic process decomposes the alumina. The metal thus extracted sinks down on to the cathode, whilst the oxygen is liberated on the underside of the anode. The anode is thus oxidized and is con-sumed, whilst at the same time the alumina content in the bath is reduced. When the alumina concentration in the bath falls below a certain critical value - about 2~ - depending upon the temperature of the bath and the current density of the anode etc., the steady electrolysis process is replaced by an anode e~fect. This reveals itself in the form of a sudden increase in the resistance of the electrolytic cell which, in the course of seconds, can increase tenfold. This increase in resistance is normally attributed to a layer of gas under the anode, see for example Norwegian patent No. 123318.
To indicate the presence of an anode effect, an electric incandescent lamp is connected across the cell. It lights up on anode effect because of the higher voltage. The normal practice is to endeavour to quench or terminate an anode effect as soon as possible, because it brings with it a number of disadvantages.
The sharp increase in resistance can result in a loss of energy in other pots in the series, thus disturbing operations. The extra energy resulting from this higher resistance causes the pot undergoing anode effect to heat excessively causing the electrolyte to evaporate with consequent large direct loss of bath vapours, mainly fluorides. This emission of fluorides to the atmosphere requires costly scrubbing.
If an anode effect is allowed to remain active too long, the operatlon of the pot is substantially disturbed and this requires i ~ , ~ . ~
extra efforts on the part of personnel to bring the pot back into normal operation, whilst at the same time output falls.
To quench anode effect, the alumina concentration in the bath under the anode must be raised. The earlier method of doing this was that the operator manually broke ~he crust around the anode, whereby the alumina which had been laid on top of the crust for pre-heating, fell down into the melt. The operator used a heavy iron implement to mix the alumina into the bath and then to rake under the anode with vigorous movements. Another method of quenching anode effect was to knock a hole in the crust and insert a wooden pole down into the bath under the anode. The gas liberated from the pole resulted in a powerful stirring of the bath, thus quenching the anode effec~. The pole has sub-sequently in a number of instances been replaced by an air lance, i.e. a tube which is used to blow compressed air down into the bath and thus to bxing about a particularly vigorous stirring under the anode.
These methods of quenching anode effect require heavy work in a hot and gas~filled atmosphere. A number o~ attempts have there-fore been made to mechanize and automate these operations.
British patent no. 853056 describes a method whereby an audio-frequency vibrator i~ used for quenching anode effect. How this procedure quenches anode effect is not explained. `
In US patent no. 2560854, a procedure is described for terminat-ing anode effect by slowly swinging the anode from a region in the electrolyte with low concentration of alumina to a region with a higher alumina concentration. It is clear that this method will mix alumina and bath and thus help to quench the anode effect, but it requires complicated and expensive equip-ment.
Norwegian patent no. 123318 discloses a method of quenching anode effect which is built on the principle that the entire anode is lowered ~o between 30 and 6 % of the normal interpolar distance, and then raised again. This lowering is started when the voltage drop across the cell exceeds 150 % of the normal working voltage, and the anode ls raised again under the control of a timing device incorporating a cam mechanism. Whilst the anode is in its lower position, an apparatus for feeding alumina to the bath is activated, so that an alumina concentration of 2-6 ~ in the bath is achieved. This procedure will doubtless reduce the amount of manual work involved in quenching anode effect, but it has nevertheless certain disadvantages. When the anode is lowered, the level of the ba-th rises because the anode must, of necessity, displace fluid. The pot shells have therefore to be somewhat higher than usual. As the bath rises, it will come into contact with the crust along the sides of the pot. This will, in time, result in a mixing of bath and alumina which solidifies forming a crust. This crust will have better heat conductivity than pure alumina and will thus iead to heat loss along the sides.
In those cases where bath overflows in connection with this so-called anode pumping, the heat content in the bath which flows out over the crust will be dissipated to the surroundings, and the spilt bath causes extra work.
In modern smelters, computers are used to control many of the pot operations. An important parameter in control strategy is the reference resistance of a pot. This is around 20 microohm and is defined as the pot voltage minus the decomposition voltage divided by the potline amperage.
In addition to the disadvantages inherent in NP 123318, there is also the increase in the reference vol~age, which means a higher consumption of energy in production.
The inventors have now found a method of quenching anode effect 3n whereby the above-mentioned difficultles are avoided. The principle of the method is that the anode is lowered at the one end whilst at the same time the other end is raised, when anode effect has occurred and is to be quenched. In other words, instead of lowering the entire anode, only a part of it is _ 4 -8~
lo~ered, whilst the opposite end is raised. The anode is thus rocked about an axis, which axis may lie either in the longi-tudinal direction of the anode or in the transverse direction.
This method is called anode rocking and has obvious advantages:
1) The surface of the bath remains at the same level. The bath will merely flow from the one end to the other. This can be advantageous for mixing of low and high alumina concentration in the bath. 2) The wearing face of the anode will be inclined, so that the gas and the gas film can more readily escape.
3) It is not necessary to make the cathode shells higher in order to contain the bath. 4) The energy consumption is kept down because the thermal insulation efficiency of the crust is not impaired by its being mixed with molten bath and alumina.
5) The loss of energy through molten bath flooding over the crust is avoided. 6) There is no spilling of bath on to the floor.
Thus, the present invention provides a method of quenching anode effect when producing aluminium by electrolytic reduction charac-terized by anode rocking whereby the anode, when anode effect has started, is placed in an inclined position so that its ~' wearing surface forms an angle of up to 20 degrees with the `
horizontal and the anode is ~lternately rocked about either its longitudinal or transverse axis and then allowed to rest in its inclined position until the anode effect is quenched, whereupon the anode is returned to its normal horizontal position.
It is obvious that the performance of anode rocking imposes certain requirements on the mechanical equipment, but the type of equipment in general use today in modern pots can usually be readily adapted, only minor additional installations being required.
The anode is usually suspended in jacks, which are operated by lifting motors at each end of the anode. These motors have to be operated independently of one another, only through impulses from a common control device.
~ 8~ ~
The working program for anode rocklng can be easily fitted into existing programs.
The work rhythm for a modern potroom prepared for the quenching of anode effect by anode rocking will comprise the usual operations in the usual sequence: alumina feed on to the crust, crust breaking outside anode effect and crust breaking durlng anode effect, followed by anode rocking.
Even if these operations are performed in all potlines, the routines will not be identical in the different plants.
On the basis of trials, the inventors have arrived at a prefer-red work method, but all methods are dependent on the apparatus and the operational characteristics of the method regarding time periods for anode rocking.
On the occurrence of anode effect, i.e. on exceeding a preset cell voltage (reference voltage), anode rocking is initiated by a control device, and lasts from 0-80 seconds whilst the anode is in an inclined positionO This is followed by a resting period of about 60 seconds to see whether the anode effect will reoccur. If it does not do so, the control device completes the order cycle for anode effect quenching by straightening up the anode and placing it in its normal position. Should, on the other hand, a new anode effect occur, the anode will be lowered about 10 mm whilst still ln the inclined position, but will be returned - 5a -to normal position after a short time, for example lo seconds, whereupon the order cycle will be terminated by straightening up the anode.
The times and durations stated here refer to given pot equipment.
It will be obvious that the invention can equally we].l be per-formed using other parameter values, with this reducing the scope of the invention.
During anode rocking, it has been shown that the lowest paxt of the anode carries a considerably higher current than normal, loo~ or more but, surprisingly enough, this has not proved to have any harmful effect. Weither has it been found that anode rocking has had any adverse mechanical consequences or operational com plications.
It is pointed out that the desired effect, the quenching of anode `
effect, is probably due to two aspects of anode rocking:
1) The bath is set in motion in a manner which will lead to the mixing in of bath with a higher alumina content under the anode.
2) wnen the anode is placed in an inclined position, i~ is easier for gas bubbles and film und~r the anode to escape.
Movement of the bath will also be favourable to promote the escape of gas film and bubbles. To achieve the desired effect, the wearing face of the anode must adopt an angle of up to 20 from the horizontal.
Movement of the bath will also be favourable to promote the escape of gas film and bubbles. To achieve the desired effect, the wearing face of the anode must adopt an angle of up to 20 from the horizontal.
Claims (3)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of quenching anode effect when producing aluminium by electrolytic reduction characterized by anode rocking whereby the anode, when anode effect has started, is placed in an inclin-ed position so that its wearing surface forms an angle of up to 20 degrees with the horizontal and the anode is alternately rocked about either its longitudinal or transverse axis and then allowed to rest in its inclined position until the anode effect is quenched, whereupon the anode is returned to its normal horizontal position.
2. A method according to claim 1 wherein anode rocking is initiated by voltage across a cell which exceeds a certain preset value.
3. A method according to claim 1 wherein anode rocking occurs for 0-80 seconds followed by a rest period of about 60 seconds in order to determine whether anode effect reoccurs, whereupon when it has stopped, the anode is returned to its normal position and if it has not, the anode is further lowered while still in its inclined position and anode rocking and resting is again initiat-ed until the anode effect is quenched.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000324700A CA1148892A (en) | 1979-03-30 | 1979-03-30 | Quenching anode effect by anode rocking |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000324700A CA1148892A (en) | 1979-03-30 | 1979-03-30 | Quenching anode effect by anode rocking |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1148892A true CA1148892A (en) | 1983-06-28 |
Family
ID=4113904
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000324700A Expired CA1148892A (en) | 1979-03-30 | 1979-03-30 | Quenching anode effect by anode rocking |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1148892A (en) |
-
1979
- 1979-03-30 CA CA000324700A patent/CA1148892A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101684813B1 (en) | Electrolysis tank used for aluminum electrolysis and electrolysis process using the electrolyzer | |
| US5024737A (en) | Process for producing a reactive metal-magnesium alloy | |
| US5725744A (en) | Cell for the electrolysis of alumina at low temperatures | |
| CN104818499B (en) | A kind of electrolysis is bench of burners | |
| US7731824B2 (en) | Measuring duct offgas temperatures to improve electrolytic cell energy efficiency | |
| CN105088284B (en) | A kind of electrolytic furnace | |
| WO2016082726A1 (en) | Electrolysis furnace | |
| US4392926A (en) | Process and apparatus for production of aluminum | |
| AU2005250240B2 (en) | High stability flow-through non-carbon anodes for aluminium electrowinning | |
| CA1148892A (en) | Quenching anode effect by anode rocking | |
| RU2499085C1 (en) | Electrolysis unit for aluminium manufacture | |
| WO2004018736A1 (en) | Utilisation of oxygen evolving anode for hall-heroult cells and design thereof | |
| CN217839161U (en) | Cluster formula rare earth metal fused salt electrolytic device | |
| US20040237710A1 (en) | Electrolytic reducion of metal oxides | |
| AU659247B2 (en) | Cell for the electrolysis of alumina preferably at low temperatures | |
| EP0017653A1 (en) | Quenching anode effect by anode rocking | |
| CN114752967A (en) | Cluster type rare earth metal fused salt electrolysis device | |
| EP1147245B1 (en) | Electrolytic cell with improved alumina supply | |
| US20050040047A1 (en) | Use of infrared imaging to reduce energy consumption and fluoride comsumption | |
| Frary | The electrolytic production of aluminum | |
| EP0353943A1 (en) | Process for terminating anode effects during the production of aluminum | |
| RU2164556C2 (en) | Method for protecting graphite lining of aluminium cell | |
| CN2641061Y (en) | Solid aluminum calcining appts. for aluminum electrolyzer | |
| Nakamura et al. | Process and Apparatus for Producing Dysprosium--Iron Alloy and Neodymium--Dysprosium--Iron Alloy | |
| US20030226760A1 (en) | Aluminium electrowinning with metal-based anodes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |