AU2016339054A1 - Series of electrolysis cells for the production of aluminium comprising means for balancing the magnetic fields at the end of the line - Google Patents
Series of electrolysis cells for the production of aluminium comprising means for balancing the magnetic fields at the end of the line Download PDFInfo
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- AU2016339054A1 AU2016339054A1 AU2016339054A AU2016339054A AU2016339054A1 AU 2016339054 A1 AU2016339054 A1 AU 2016339054A1 AU 2016339054 A AU2016339054 A AU 2016339054A AU 2016339054 A AU2016339054 A AU 2016339054A AU 2016339054 A1 AU2016339054 A1 AU 2016339054A1
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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
- C25C3/16—Electric current supply devices, e.g. bus bars
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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
- C25C3/20—Automatic control or regulation of cells
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Abstract
The invention relates to a series (1) of electrolysis cells (100) intended for the production of aluminium, comprising: two rectilinear and parallel lines (F, F') of electrolysis cells electrically connected in series, a connecting conductor (20) between a first end cell (100') of one line and the corresponding first end cell (100') of the other line, and at least one magnetic balancing circuit (21) for balancing the end of line cells, comprising a first electrical conductor (22) for magnetic balancing of the end cells extending along one of the lines of cells, only opposite an end portion (P) of the first line of cells.
Description
The invention relates to a series (1) of electrolysis cells (100) intended for the production of aluminium, comprising: two rectilinear and parallel lines (F, F') of electrolysis cells electrically connected in series, a connecting conductor (20) between a first end cell (100') of one line and the corresponding first end cell (100') of the other line, and at least one magnetic balancing circuit (21) for balancing the end of line cells, comprising a first electrical conductor (22) for magnetic balancing of the end cells exten ding along one of the lines of cells, only opposite an end portion (P) of the first line of cells.
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L'invention a pour objet une serie (1) de cellules d'electrolyse (100) destinee a la production d'aluminium comportant : deux files (F, Fj rectilignes et paralleles de cellules d'electrolyse raccordees electriquement en serie, un conducteur de raccordement (20) entre une premiere cellule d'extremite (100') d'une file et la premiere cellule d'extremite (100') correspondante de l'autre file, et au moms un circuit d'equilibrage magnetique (21) des cellules d'extremite de file comportant un premier conducteur electrique (22) d'equilibrage magnetique des cellules d'extremite s'etendant le long d'une des files de cellules uniquement en regard d'une portion d'extremite (P) de la premiere file de cellules.
SERIES OF ELECTROLYSIS CELLS FOR THE PRODUCTION OF ALUMINIUM
COMPRISING MEANS FOR BALANCING THE MAGNETIC FIELDS AT THE END
OF THE LINE
Scope of the invention
The invention relates to the production of aluminum by igneous electrolysis, namely by electrolysis of alumina in solution in a molten cryolite bath, known as an electrolyte bath, using the well-known Hall-Heroult process. The invention particularly relates to the balancing of the magnetic field of series of electrolytic cells, typically rectangular in shape and arranged transversely.
Background of related art
Plants for producing aluminum by igneous electrolysis contain a large number of electrolytic cells - typically several hundred - arranged in line, and electrically connected in series using connecting conductors, so as to form two or more parallel rows which are electrically interconnected by connecting conductors. The cells, which are rectangular in shape, can be oriented either longitudinally (i.e. so that their long axis is parallel to the longitudinal axis of the rows) or transversely (i.e. so that their long axis is perpendicular to the longitudinal axis of the rows).
A large number of arrangements for cells and connecting conductors has been proposed in order firstly to limit losses by Joule effect, and secondly to reduce the impact of magnetic fields generated by the connecting conductors and the neighboring cells on the electrolysis process. For example, French patent application FR 2 552 782 (corresponding to US Patent No. 4 592 821) in the name of Aluminium Pechiney describes a row of electrolytic cells arranged transversely and able to operate industrially at intensities greater than 300 kA. According to this patent, the magnetic stability of the cells is ensured by the configuration of the connecting conductors, particularly those passing under the pot.
Also, French patent application FR 2 425 482 (corresponding to US Patent No. 4 169 034) in the name of Aluminium Pechiney describes an aluminum smelter with at least two parallel rows of neighboring cells in which the magnetic field generated by current flowing in the next row of cells is compensated for by means of at least one independent correction conductor passing on the side of the pots, along all the cells of the series and traversed by a direct correction current.
For example, French patent application FR 2 583 069 (corresponding to US Patent No. 4 713 161) also in the name of Aluminium Pechiney describes a row of electrolytic cells arranged transversely able to operate industrially at intensities up to 500 to 600 kA. According to this patent, the costs of building and installing the circuits are minimized through the use of connecting conductors, as small and as direct as possible, while magnetic stability and Faraday efficiency are maximized through the use of independent correcting conductors, arranged parallel to each row and on each side thereof.
Arranging the electrolytic cells in rows has the advantage of simplifying the configuration of the connecting conductors and standardizing the map of magnetic fields. However, the presence of connecting conductors between the rows interferes with the uniformity of the map of magnetic fields of the cells at the end of each row.
US patents US 3 775 280 and US 4 189 368 propose arrangements of connecting conductors for series of longitudinally arranged cells designed to limit the interference caused by these connecting conductors. In addition, the intensities of such cells do not generally exceed 100 kA.
European EP 0 342 033 and Chinese CN 2 477 650 patent applications describe arrangements of connecting conductors applicable to series of cells arranged transversely to limit the interference caused by these connecting conductors. These documents relate to series of electrolytic cells equipped with pots for intensities of the order of 300 kA.
Patent FR 2 868 436 (corresponding to US patent US 7 513 979) in the name of Aluminium Pechiney describes a series of two rows of cells arranged transversely and provided with at least one correction conductor along the inside of the rows, with a particular arrangement of the correction conductor consisting of making a transverse section running along the length of the first end-of-row cell at a defined distance and traversed by a current flowing from the inner side toward the outer side of the rows of cells. Such an arrangement can compensate adequately for the magnetic field generated by the connecting conductors in a small number of end cells (about 1 to 3) while a larger number of end cells (about 1 to 10 ) are disturbed by the magnetic field generated by the connecting conductors. Consequently a large number of end-of-row cells are unstable and difficult to operate.
The applicant therefore attempted to find economically and technically satisfactory solutions to balance the magnetic fields of end-of-row cells, particularly series of cells formed from long rectangular cells, arranged transversally.
Description of the invention
To this end, the invention relates to a series of electrolytic cells for the production of aluminum by igneous electrolysis using the Hall-Heroult process, comprising:
- at least one first and one second rectilinear row, parallel to each other, of electrolytic cells electrically connected in series,
- a connecting conductor between a first end cell of the first row and the corresponding first end cell of the second row, and characterized in that the series comprises at least one magnetic balancing circuit for the end-of-row cells having a first electrical conductor for magnetic balancing of the end-of-row cells extending along the first row of cells opposite only an end portion of the first row of cells.
The applicant noted that, in the absence of a magnetic balancing circuit for the end-ofrow cells as defined above, the end-of-row cells are particularly affected by an additional average vertical magnetic field ΔΒζ, when the cells of the central portion of the rows are properly balanced magnetically. The invention therefore aims to maintain the additional vertical field ΔΒζ within a range limited by a minimum value and a maximum value around a target value close to zero.
The applicant had the idea of arranging said first electrical conductor near the notoriously unstable end cells of the row of cells in order to make an electric current flow in said first electrical conductor to compensate for the magnetic field produced by the connecting conductors between the rows, and to balance the magnetic fields in the pots of the end electrolytic cells.
The first electrical conductor extending along the row of cells extends parallel or substantially parallel to the longitudinal axis of the row of cells.
By along the row of cells, the applicant means that the conductor extends in direct proximity to the row of cells, so that its impact on the magnetic field in the nearby cells is maximized, and typically at a distance of less than 5 meters and advantageously less than 3 meters.
This configuration makes it possible to substantially limit the vertical magnetic field Bz in these end cells. The use of such a magnetic balancing circuit for the end-of-row cells further allows fine adjustment of the magnetic balance because of the additional adjustable parameters it provides.
The first electrical conductor is traversed when the series is operating by means of a direct current for magnetic balancing of the end-of-row cells.
The first electrical conductor extends continuously along a plurality of adjacent cells of the end portion for which an imbalance of the vertical magnetic field due to the presence of the connecting conductor is observed.
Such an end portion of the first row of cells typically contains from 3 to 10 cells, and 5 preferably 6 to 8 cells.
For the stabilizing effect on the magnetic field of the end-of-row cells to be adequate and economically viable, the first magnetic balancing electrical conductor extends advantageously over a length at least equal to three times the distance between two cells (the center distance between two cells being the distance between the central longitudinal axes of two adjacent electrolytic cells, typically corresponding to 5 to 10 meters).
The connecting conductor is no longer a destabilizing element for electrolytic cells arranged beyond the tenth cell from the first end cell, on account of the great distance between these cells and the connecting conductor.
In the case of series of existing electrolytic cells, known magnetic balancing means for end cells may have already been installed and properly balance the first end cell. In this case, the first magnetic balancing electrical conductor does not need to extend along the first end cell.
The invention also relates to a method of using a series of electrolytic cells. In operation, the rows of electrolytic cells and the connecting conductor are traversed by an electrolysis current and the first magnetic balancing electrical conductor is traversed by a balancing electric current:
- flowing in the same direction as the electrolysis current flowing in the first row of cells if the first magnetic balancing electrical conductor is located along the first row of cells on the side of the second row of electrolytic cells;
- flowing in the opposite direction with respect to the electrolysis current flowing in the first row of cells if the first magnetic balancing electrical conductor is located along the first row of cells on the side opposite the second row of electrolytic cells.
In this way, at the end-of-row cells along which the first electrical conductor extends, 30 the electrical balancing current, as it passes through the first electrical conductor, generates a vertical magnetic field opposite to the vertical magnetic field generated by the electrolytic current flowing through the connecting conductor.
According to one embodiment, the magnetic balancing circuit for the end-of-row cells comprises a second electrical conductor parallel to the first magnetic balancing electrical conductor for the end-of-row cells. This parallel second electrical conductor participates in closing the magnetic balancing circuit and potentially in producing a magnetic balancing circuit having a plurality of serial loops. Also, this second electrical conductor is traversed by the electrical balancing current flowing in the opposite direction with respect to the balancing electric current flowing through the first electrical conductor. This second electrical conductor is advantageously arranged to improve the magnetic configuration of the end cells of the first row or the second row, and at least so that any negative impact it may have on the magnetic balancing of the ends cells is minimized and less than the positive impact of the first electrical conductor.
According to a particular embodiment, the second electrical conductor extends along the first row of cells opposite only the end portion of the first row of cells, the first and the second electrical conductor extending along opposite sides of the first row of cells. The vertical magnetic field generated by the flowing of the same balancing electric current, in the opposite direction, on the other side of the cell row, in the second electric conductor is added to the vertical magnetic field generated by the flow of an electric balancing current in the first electrical conductor to counteract the destabilizing vertical magnetic field generated by the current flowing in the connecting conductor.
In another particular embodiment, the second electrical conductor extends from the same side of the first row of cells as the first electrical conductor, the distance between the first electrical conductor and the first row of cells being smaller than the distance between the second electric conductor and the first row of cells. In this way, as the second electrical conductor is on the same side as, but more distant from the first row of electrolytic cells than the first electrical conductor, the vertical magnetic fields generated by the flow of balancing electric current in the opposite direction in the first and second electrical conductors oppose each other, but with a lesser intensity for the vertical magnetic field generated by the flow of balancing electric current in the second electrical conductor than in the first electrical conductor, at the level of the end-of-row cells along which the first electrical conductor extends.
Advantageously, the second electrical conductor is farther from the electrolytic cells of the first row than the first electrical conductor such that the ratio of the vertical magnetic field values generated by the same balancing current flowing in the second electric conductor and in the first electrical conductor is less than 0.5 and preferably less than 0.3, at the level of the end-of-row cells along which the first electrical conductor extends.
According to a particular embodiment, the second electrical conductor extends along the second row of cells opposite only the end portion of the second row of cells. In this way, the magnetic balancing circuit helps to magnetically balance both the end cells of the first row of cells and the corresponding end cells of the second row of cells.
According to a preferred embodiment, the magnetic balancing circuit is connected to a specific electric power station. The intensity of the current flowing in the magnetic balancing circuit may advantageously be easily controlled and adjusted. Specific electric power station means that this power station does not supply power to the electrolysis circuit (connecting conductors), or that of the correction conductors designed to perform magnetic correction on all cells in the series.
According to a preferred embodiment, the magnetic balancing circuit for the end-of-row cells has two ends which are connected to conductors electrically connecting the electrolytic cells to each other. The magnetic balancing circuit for the end-of-row cells is then powered via at least one portion of the electrolysis current flowing in the cells and forms part of the electrolysis circuit through which the electrolysis current of the series flows.
According to a preferred embodiment, the magnetic balancing circuit is connected to the conductors electrically connecting the electrolytic cells to each other in parallel with said one or more parallel electrical conductors. So only a portion of the electrolysis current flows through the magnetic balancing circuit.
Advantageously, the magnetic balancing circuit for the end-of-row cells forms part of the connecting conductor. Electrical balancing between the so-called parallel electrical conductors and the magnetic balancing circuit is thereby facilitated.
According to a preferred embodiment, the series of electrolytic cells comprises a correction circuit comprising at least one first correction conductor extending along the first row, a second correction conductor extending along the second row, and at least one connection correction conductor between the first and second correction conductors, in which the magnetic balancing circuit of the end-of-row cells comprises two ends which are connected to the correction circuit.
As presented in the introduction, some series have one or more correction circuits extending along all the series of electrolytic cells to correct the destabilizing magnetic fields generated by the high-intensity currents flowing in the conductor circuit from cell to cell or in the neighboring row of cells. The correction circuit is an integral part of the series and is supplied with electric current. This solution is therefore particularly advantageous because it does not require the installation of a specific power station representing a significant capital outlay and may also be difficult to install because of the space required.
Advantageously, the magnetic balancing circuit of the end-of-row cells is connected in series between two portions of the correction circuit. As the first and second correction conductors extend along all the electrolytic cells, it is sufficient to connect the magnetic balancing circuit of the end-of-row cells in series to an intermediate point of the correction circuit at an appropriate place along the cell rows. The correction current in the correction circuit also flows through the magnetic balancing circuit and becomes, in this magnetic balancing circuit, the magnetic balancing current.
According to a preferred embodiment, the first correction conductor extends along the first row towards the second row, and the second correction conductor extends along the second row on the side of the first row of cells. The first conductor and the second conductor of the magnetic balancing circuit connected to the correction circuit are advantageously arranged outside the two rows of cells. The outside of the rows of cells, opposite the correction circuit is less crowded than the inside and fitting the magnetic balancing circuit is easier. Such a magnetic balancing circuit may in particular be used on an existing series already having a correction circuit arranged inside the two rows of cells.
According to a particular embodiment, the connection conductor has a magnetic balancing conductor for the first end cell running along the first end cell perpendicular to the longitudinal axis of the row of cells, and the first electrical conductor does not extend along the first end cell. The first end cell is already balanced magnetically via the magnetic balancing conductor of the first end cell, so that changing its magnetic field using the first electrical conductor would result in destabilizing it.
According to a particular embodiment, the magnetic balancing circuit of the end-of-row cells comprises a transverse conductor electrically connecting the correction circuit to the first electrical conductor, the transverse conductor extending below the row of cells.
According to one embodiment, the magnetic balancing circuit of the end-of-row cells forms a plurality of loops and the first magnetic balancing electrical conductor is formed by a plurality of loop strands extending side by side along the first row of cells opposite only the end portion of the first row of cells. The current flows in the same direction in each of the loop strands of the first electrical conductor and the impact on the magnetic field of the current flowing in the first electric conductor is the sum of the impact on the magnetic field of the current flowing in each of the loop strands forming the first electrical conductor.
According to a preferred embodiment, the cells are arranged transversely in relation to the rows of cells.
The electrolysis cells are typically connected electrically in series by means of electrical connecting conductors connecting the cathode of one electrolytic cell to the anode of the next electrolytic cell.
The invention is described in detail below using the appended figures.
Figure 1 shows, schematically and in cross section, two successive electrolytic cells (n; n + 1) typical of a row of cells.
Figures 2 to 4 show, schematically, different embodiments of a series of electrolytic cells according to the invention having two rows and magnetic balancing circuits for the end cells.
Figure 5 illustrates, schematically, an embodiment of the invention in which a portion of the electrolysis current of the series is used to power the magnetic balancing circuits for the end cells.
Figure 6 illustrates, schematically, a series of electrolytic cells according to prior art having two rows and a correction circuit.
Figure 7 illustrates, schematically, one end of a series of electrolytic cells according to the invention having two rows and magnetic balancing circuits for the end cells connected to a correction circuit.
Figure 8 illustrates, schematically, one end of a series in which each magnetic balancing circuit forms two loops.
Figure 9 illustrates, schematically, one end of a series of electrolytic cells according to the invention comprising two rows, a particular arrangement of the connecting conductor making it possible to magnetically balance the first end cell and the magnetic balancing circuits for the end cells connected to a correction circuit.
The invention relates to a series 1 of electrolytic cells comprising, as shown in figures 2 to 5, 7 and 8, a plurality of electrolytic cells 100, 100' of substantially rectangular shape, which are arranged so as to form at least two rows F, F' of substantially rectilinear, parallel cells, each having a longitudinal axis A, A'.
The cells 100 are typically arranged transversely (i.e. so that their major axis or long side is perpendicular to the longitudinal axis A, A' of said rows) and located at the same distance from each other. The electrolytic cells 100 typically have a long side greater than 3 times the short side.
Rows F, F' are separated by a distance dependent on technological choices which take into account the intensity l0 of the electrolysis current of the series and the configuration of the conductor circuits. Distance D between the two rows is typically between 30 and
100 m for recent series.
As shown in figure 1, each electrolytic cell 100 of series 1 typically comprises a pot 3, anodes 4 supported by fixing means typically including a stem 5 and a multipode 6 and mechanically and electrically connected to an anode frame 7 by connecting means 8. Pot 3 comprises a metal shell, usually reinforced by stiffeners, and a crucible formed by refractory materials and cathode elements arranged within the pot shell. The pot shell generally has vertical side walls. In operation, anodes 4, typically made of a carbonaceous material, are partially immersed in an electrolyte bath (not shown) contained in the pot. Pot 3 comprises a cathode assembly 9 provided with cathode rods 10, typically made of steel, one end of which 11 comes out of the pot 3 so as to enable electrical connection to the connecting conductors 12 to 17 between cells.
The connecting conductors 12 to 17 are connected to said cells 100 so as to form an electrical series, which makes up the electrical electrolysis circuit of the series of electrolytic cells. The connecting conductors typically comprise flexible conductors 12, 16, 17, upstream connecting conductors 13 and uprights 14, 15. The connecting conductors, particularly upstream, may, in whole or part, go under the pot and/or round it.
Figure 2 schematically illustrates an embodiment comprising a series consisting of two rows F, F' of electrolytic cells 100 oriented transversely to the longitudinal axis A, A' of the rows. The rows are rectilinear and arranged parallel to each other. The rows, and more particularly the corresponding first end cells 100' of the two rows F, F', are electrically interconnected by connecting conductors 20. Connecting conductors 20 are formed only of electrical conductors or electrical conductors in conjunction with an electric power station.
Advantageously, the series also includes four electric magnetic balancing circuits 21 for the end cells. In this way, a magnetic balancing circuit 21 balances the magnetic field at each of the two ends of the two rows F, F'. These magnetic balancing circuits are arranged at the level of the end-of-row cells outside rows F, F' of cells, i.e. outside the space between the two rows F, F' of cells.
Each magnetic balancing circuit 21 comprises a first magnetic balancing electrical conductor 22 for the end cells extending along a row F, F' of cells opposite only an end portion P of said row F, F' of cells.
End cells means the n adjacent end cells starting from the first end cell 100' of a row of cells that are magnetically impacted by the flow of the electrolysis current l0 in the connecting conductor 20. Typically n is between 3 and 10. The end portion P of the row of cells opposite which the first electrical conductor 22 extends is therefore limited to a row segment extending along the end cells.
Each magnetic balancing circuit 21 further comprises a second electrical conductor 23 5 substantially parallel to the first magnetic balancing electrical conductor 22 for the end cells and arranged at a greater distance from the row of cells than the first electrical conductor 22.
The first and second electrical conductors 22, 23 are electrically connected together by means of transverse conductors 24 to form a closed electrical circuit around an electric power station 30 advantageously connected to a point on the second electrical conductor 23.
The first electrical conductor 22, which extends along row F, F' in front of the end cells, substantially limits the vertical magnetic field Bz in the end cells when it is traversed by a magnetic balancing current for the end cells of intensity hcells and in a direction opposite to the electrolysis current l0 flowing in the end-of-row cells F, F' in front of which it extends. The second electrical conductor 23 is more distant from the end cells than the first electrical conductor 22 so that the magnetic field it generates has little impact on the stability of the end cells. Because of their distance and their short length, the transverse conductors 24 have little impact on the stability of the end cells.
Advantageously, for a series traversed by an electrolysis current l0 between 300kA and 600kA with rows of cells spaced out by 30 to 80 meters:
- the first electrical conductor 22 running along the row of cells extends to a distance from the edge of the end cells of less than 5 meters, and advantageously less than 3 meters;
- the second electrical conductor 23 is arranged at a distance from the edge of the end cells greater than 7 meters, and advantageously greater than 10 meters;
- the balancing current h of the end cells is between 30 and 150kA.
The intensity of the balancing current l1; and therefore the resulting magnetic balancing can be easily controlled and adjusted because of the use of a specific electric power station.
Figure 3 schematically illustrates another embodiment in which each magnetic balancing circuit 21 surrounds the end cells of the row of cells. Each magnetic balancing circuit comprises:
- a first magnetic balancing electrical conductor 22 for the end cells extending along a row F, F' of cells opposite only an end portion P of said row F, F' of cells on the outside relative to the two row of cells.
- a second magnetic balancing electrical conductor 23' for the end cells and extending along the same row F, F' of cells as the first electrical conductor 22 opposite only an end portion P of row F, F' of cells, on the inside relative to the two row of cells, i.e. between the two rows F, F' of cells;
- transverse conductors 24 electrically connecting the first and second electrical conductors 22, 23' to form a closed electrical circuit around an electrical power station 30 connected to an electrical point of the second electric conductor 23'.
The first and second electrical conductors 22, 23’ which extend along row F, F' in front of the end cells, make it possible to substantially limit the vertical magnetic field Bz in the end cells when they are traversed by a magnetic balancing current for the end cells of intensity h in a direction opposite to the electrolysis current l0 flowing in the end-of15 row cells F, F' in front of which it extends for the first electrical conductor 22 and in an identical direction to the electrolysis current l0 flowing through the cells at the end of row F, F' in front of which it extends for the second electrical conductor 23'. In this embodiment, the first and second electrical conductors 22, 23' have a cumulative beneficial magnetic impact.
The transverse conductors 24 may pass under the rows F, F' of cells. Because of their short length, the transverse conductors 24 have little impact on the stability of the end cells.
Advantageously, for a series traversed by an electrolysis current l0 between 300kA and 600kA with rows of cells spaced out by 30 to 80 meters:
- the first and second electrical conductors 22, 23’ running along the row of cells extend to a distance from the edge of the end cells of less than 5 meters, and advantageously less than 3 meters;
- the balancing current h for the end cells is between 15 and 75kA.
Figure 4 illustrates schematically another embodiment of a series of two rows F, F' of cells comprising two magnetic balancing electric circuits 21 for the end cells, in which each magnetic balancing circuit 21 is arranged between the two rows F, F' of cells. Each magnetic balancing circuit comprises:
- a first magnetic balancing electrical conductor 22 for the end cells extending along the first row F, F' of cells opposite only an end portion P of said row F of cells on the inside relative to the two row of cells.
- a second magnetic balancing electrical conductor 23” for the end cells extending along the second row F’ of cells opposite only an end portion P’ of said row F’, of cells, on the inside relative to the two rows of cells.
- transverse conductors 24 electrically connecting the first and second electrical conductors 22, 23 to form a closed electrical circuit around an electrical power station 30 connected to a point on one of the transverse conductors 24.
The first and second electrical conductors 22, 23' which respectively extend along rows
F and F' in front of the end cells, make it possible to substantially limit the vertical magnetic field Bz in the end cells in front of which they extend when traversed by a magnetic balancing current for the end cells of intensity h, in the same direction as the electrolysis current l0 flowing in the end-of-row cells F, F' in front of which they extend.
In this embodiment, the first and second electrical conductors 22, 23 have a beneficial magnetic impact on the end cells of the two rows F and F' of cells that they respectively run along.
The transverse conductors 24 of substantial length between the two row F, F' only slightly negatively impact the stability of the cells, because the current h flowing in the transverse conductors 24 is less intense than the electrolysis current l0 flowing in the connecting conductors 20. The negative impact of these transverse conductors 24 is well below the positive impact of the first and second conductors which are positioned as close as possible to the end cells.
Advantageously, for a series traversed by an electrolysis current l0 between 300kA and
600kA with rows of cells spaced out by 30 to 80 meters:
- the first and second electrical conductors 22, 23 extend to a distance from the edge of the end cells of less than 5 meters, advantageously less than 3 meters;
- the balancing current h of the end cells is between 30 and 150kA.
Figure 5 illustrates schematically one end of a series with magnetic balancing electric circuits 21 for the end cells using the same magnetic balancing principles as those presented with reference to figure 2. The method for supplying electric current to this magnetic balancing circuit differs. Instead of being supplied with electric current by at least one specific electric power station, each magnetic balancing circuit 21 is powered from the electrolysis current l0 flowing in the series of electrolytic cells.
The magnetic balancing circuit 21 comprises a first electrical conductor 22, a second electrical conductor 23 and transverse conductors 24 electrically connecting the first and second electrical conductors to each other or electrically connecting the first and second electrical conductors to conductors electrically connecting the corresponding end electrolytic cells 100' of two adjacent rows to each other.
The transverse conductors 24 form two ends of the magnetic balancing circuit which are connected to conductors electrically connecting two electrolytic cells together. The magnetic balancing circuit of the end cells forms part of the electrolysis circuit, and more particularly the connecting conductor 20 through which the electrolysis current of the series flows.
The magnetic balancing circuit is connected to the conductors electrically connecting the end electrolytic cells 100' in parallel with a so-called parallel electric conductor 25. In operation, therefore, a portion of the electrolysis current l0, corresponding to the magnetic balancing current h, flows through the magnetic balancing circuit. Another part of the electrolysis current l0, of intensity l0 - h, flows through said so-called parallel electric conductor 25.
This embodiment has the advantage of eliminating the need to use a specific power station.
Figure 6 illustrates, schematically, a series of electrolytic cells according to prior art having two rows F, F’ of cells and a correction circuit 26 arranged between the two rows of cells. This correction circuit 26 comprises two correction conductors 27 extending along each of the rows F, F' of cells between the two rows F, F', connection correction conductors 28 between the two correction conductors 27 and an electric power station 31 for the correction circuit. Such a correction circuit serves in particular to compensate, at the level of a row, the magnetic field generated by the electrolysis current l0 flowing in the neighboring row. The correction conductors are typically traversed by a correction current l2 flowing in the same direction as the electrolysis current l0 flowing through the row that they run along.
For a series traversed by an electrolysis current l0 between 300kA and 600kA with rows of cells spaced out by 30 to 80 meters, the correction current l2 is typically between 30 and 150kA.:
Figure 7 illustrates schematically one end of a series with magnetic balancing electric circuits 21 for the end cells and a correction circuit such as that presented with reference to figure 6. The balancing magnetic circuits 21 of the end cells use the same magnetic balancing principles as those presented with reference to figures 2 and 5.
However, the method for supplying electric current to this magnetic balancing circuit differs. Each magnetic balancing circuit 21 is powered from the correction current l2 flowing in conductors 27, 28 of correction circuit 26.
The magnetic balancing circuit 21 comprises a first electrical conductor 22, a second electrical conductor 23 and transverse conductors 24 electrically connecting the first and second electrical conductors to each other or electrically connecting the first and second electrical conductors to conductors 27, 28 of correction circuit 26.
The transverse conductors 24 form in this way two ends of the magnetic balancing circuit which are connected to conductors 27, 28 of correction circuit 26. The magnetic balancing circuit 21 of the end cells then forms part of the correction circuit 26 through which the correction current flows.
The magnetic balancing circuit is more particularly connected to conductors 27, 28 of the correction circuit in series between two portions of the correction circuit. In this way, in operation, all of the correction current l2 flows in the magnetic balancing circuit. In this way, the intensity of the magnetic balancing current h is equal to the intensity of the correction current l2.
This embodiment has the advantage of eliminating the need to use a specific power station for the magnetic balancing circuit 21 for the end cells. As conductors 27, 28 of the correction circuit extend along rows F, F' along the entire length of the rows, the electrical connection of the magnetic balancing circuit 21 is easy and can be made at any point considered as appropriate. Positioning the magnetic balancing circuit 21 on the opposite side of the row F, F', in relation to the corresponding correction conductor 27 is advantageous for reasons of space and because inserting the end cells between the first electrical conductor 22 and the correction conductor 27 is particularly stabilizing for the end cells.
Figure 8 illustrates schematically one end of a series with magnetic balancing electric circuits 21 for the end cells and a correction circuit. The magnetic balancing circuit 21 of the end-of-row cells forms two loops and the first magnetic balancing electrical conductor 22 is formed by two loop strands 29 extending side by side along the row of cells opposite only the end portion P of the row of cells.
The current flows in the same direction in each of the loop strands 29 extending side by side to form the first electrical conductor 22 and the impact on the magnetic field of the current flowing in the first electric conductor is the sum of the impact on the magnetic field of the current flowing in each of the loop strands 29 forming the first electrical conductor 22.
As the magnetic balancing circuit is connected in series to the conductors 27, 28 of the correction circuit, all of the correction current l2 flows in each of the strands of loop 29 of the magnetic balancing circuit 21. In this way, the intensity of the magnetic balancing current h flowing in the first electrical conductor 22 is equal to twice the intensity of the correction current l2.
Figure 9 illustrates schematically a variant of the embodiment of figure 7 in which the connecting conductor 20 comprises a magnetic balancing conductor 40 for the first end cell 100' running along the first end cell 100' perpendicularly to the longitudinal axis of the row F, F' of cells. At least part of the electrolysis current l0flows in conductor 40 in a direction opposite to the flow direction of the electrolysis current l0 in the main leg of the connecting conductor 20 extending between the two rows F, F'. The negative magnetic impact caused by connecting conductor 20 is thereby countered at the level of the first end cell 100' bordered by the conductor 40. It is therefore unnecessary to magnetically balance this first end cell 100' by means of the magnetic balancing circuit 21 for end-ofrow cells. The end portion P of the row opposite which the first electrical conductor 22 of the magnetic balancing circuit 21 for the end-of-row cells extends then advantageously does not include the first end cell 100'. The first electrical conductor 22 extending along the row F, F' of cells opposite only an end portion P does not run along the first end cell.
The transverse conductor 24 electrically connecting conductors 27, 28 of the correction circuit 26 to the first electrical conductor 22 extends under row F, F' of cells and more particularly under the first end cell 100'.
It is thereby possible to improve the stability of the end cells of an existing electrolysis series comprising a magnetic balancing arrangement for the first end cell of the type known from European patent application EP 0 342 033 or Chinese patent application CN 2 477 650.
As shown in the figures, the electrolysis current l0 flows through rows F, F' of electrolytic cells 100 and the connecting conductor 20, and the first magnetic balancing electrical conductor 22 is traversed by an electric balancing current h:
- flowing in the same direction as the electrolysis current l0 flowing in row F, F' of cells that it runs alongside if the first magnetic balancing electrical conductor 22 is located along row F, F' on the side of the other row of electrolytic cells in the series;
- flowing in the opposite direction to the electrolysis current l0 flowing in row F, F' of cells that it runs alongside if the first magnetic balancing electrical conductor 22 is located along row F, F' of cells on the side opposite the other row of electrolytic cells in the series; The second magnetic balancing electrical conductor 23 is also traversed by the electrical balancing current h but flowing in the opposite direction to the electrical balancing current h flowing in the first magnetic balancing electric conductor 22 .
Claims (5)
1. Series (1) of electrolytic cells (100) for the production of aluminum by igneous electrolysis using the Hall-Heroult process, comprising:
- at least one first and one second rectilinear row (F, F’), parallel to each other, of
5 electrolytic cells electrically connected in series,
- a connecting conductor (20) between a first end cell (100’) of the first row and the corresponding first end cell (100’) of the second row, and characterized in that the series comprises at least one magnetic balancing circuit (21) for the end-of-row cells having a first electrical conductor (22) for magnetic
10 balancing of the end-of-row cells extending along the first row of cells opposite only an end portion (P) of the first row of cells.
2. Series of electrolytic cells according to claim 1, in which the magnetic balancing circuit (21) for the end-of-row cells comprises a second electrical conductor (23, 23’, 23”) parallel to the first magnetic balancing electrical conductor 22 for the end-of-row
15 cells.
3. Series of electrolytic cells according to claim 2, in which the second electrical conductor (23’) extends along the first row (F, F’) of cells opposite only the end portion (P) of the first row of cells, the first and the second electrical conductors (22, 23) extending along opposite sides of the first row of cells.
20 4. Series of electrolytic cells according to claim 2, in which the second electrical conductor (23) extends from the same side of the first row (F, F’) of cells as the first electrical conductor (22), the distance between the first electrical conductor and the first row of cells being smaller than the distance between the second electric conductor and the first row of cells.
25 5. Series of electrolytic cells according to claim 4, in which the second electrical conductor (23”) extends along the second row (F, F’) of cells opposite only the end portion (P’) of the second row of cells.
6. Series of electrolytic cells according to one of the preceding claims, in which the magnetic balancing circuit (21) of the end-of-row cells comprises two ends which are
30 connected to a power station (30).
7. Series of electrolytic cells according to one of claims 1 to 5, in which the magnetic balancing circuit (21) of the end-of-row cells comprises two ends which are connected to conductors electrically connecting electrolytic cells to each other.
8. Series of electrolytic cells according to one of claims 1 to 5, comprising a 5 correction circuit (26) comprising at least one first correction conductor (27) extending along the first row (F, F’), a second correction conductor (27) extending along the second row (F, F’), and at least one connection correction conductor (28) between the first and second correction conductors (27), in which the magnetic balancing circuit (21) of the end-of-row cells comprises two ends which are connected to the correction
10 circuit (26).
9. Series of electrolytic cells according to claim 8, in which the magnetic balancing circuit (21) for the end-of-row cells is connected in series between two portions of the correction circuit (26).
10. Series of electrolytic cells according to one of claims 8 and 9, in which the first 15 correction conductor (27) extends along the first row (F, F’) towards the second row, and the second correction conductor (27) extends along the second row (F, F’) on the side of the first row of cells.
11. Series of electrolytic cells according to one of claims 8 to 10, in which the first conductor (22) and the second conductor (23) of the magnetic balancing circuit (21)
20 connected to the correction circuit (26) are arranged outside the two rows (F, F') of cells.
12. Series of electrolytic cells according to one of the preceding claims, in which the connection conductor (20) has a magnetic balancing conductor (40) for the first end cell (100’) running along the first end cell perpendicular to the longitudinal axis of the row
25 (F, F’) of cells, and in which the first electrical conductor (22) does not extend along the first end cell.
13. Series of electrolytic cells according to claim 12, when it depends on claim 11 in which the magnetic balancing circuit (21) of the end-of-row cells comprises a transverse conductor (24) electrically connecting the correction circuit (26) to the first
30 electrical conductor (22), the transverse conductor extending below the row (F, F’) of cells.
14. Series of electrolytic cells according to one of the preceding claims, in which the magnetic balancing circuit (21) of the end-of-row cells forms a plurality of loops and the first magnetic balancing electrical conductor (22) is formed by a plurality of loop strands (29) extending side by side along the first row (F, F’) of cells opposite only the end
5 portion P of the first row of cells.
15. Electrolysis series according to one of the preceding claims, in which the end portion (P) of the first row (F, F ') of cells contains from 3 to 10 cells, and preferably 6 to 8 cells.
16. Method of using a series (1) of electrolytic cells (100) according to one of the 10 preceding claims, in which the rows (F, F') of electrolytic cells and the connection conductor (20) are traversed by an electrolysis current (l0) and in which the first magnetic balancing electrical conductor (22) is traversed by an electric balancing current (h):
- flowing in the same direction as the electrolysis current (l0) flowing in the first row
15 (F, F’) of cells if the first magnetic balancing electrical conductor (22) is located along the first row of cells on the side of the second row (F, F’) of electrolytic cells;
- flowing in the opposite direction with respect to the electrolysis current (l0) flowing in the first row (F, F’) of cells if the first magnetic balancing electrical conductor (22) is located along the first row of cells on the side opposite the second (F, F’)
20 row of electrolytic cells.
17. Method of using a series of electrolytic cells according to claim 16, in which the series (1) comprises a second magnetic balancing electrical conductor (23, 23', 23) and in which this second magnetic balancing electrical conductor is traversed by the electric balancing current (h) but flowing in the opposite direction to the electrical
25 balancing current (h) flowing through the first magnetic balancing electrical conductor (22).
1/5
15 16 17
Fig. 1
2/5
Fig. 4
3/5
I
Fig. 5
Fig. 6
4/5
Fig. 8
5/5 |1=|2 .-, f _ 22
Γ7 . 40 |2 — <
Fig. 9
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR15/02186 | 2015-10-15 | ||
| FR1502186A FR3042509B1 (en) | 2015-10-15 | 2015-10-15 | SERIES OF ELECTROLYSIS CELLS FOR THE PRODUCTION OF ALUMINUM COMPRISING MEANS FOR BALANCING THE MAGNETIC FIELDS AT THE END OF THE FILE |
| PCT/IB2016/001437 WO2017064547A1 (en) | 2015-10-15 | 2016-10-03 | Series of electrolysis cells for the production of aluminium comprising means for balancing the magnetic fields at the end of the line |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2016339054A1 true AU2016339054A1 (en) | 2018-04-12 |
| AU2016339054B2 AU2016339054B2 (en) | 2021-06-10 |
Family
ID=54707843
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2016339054A Ceased AU2016339054B2 (en) | 2015-10-15 | 2016-10-03 | Series of electrolysis cells for the production of aluminium comprising means for balancing the magnetic fields at the end of the line |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP3362590B1 (en) |
| CN (1) | CN108368624B (en) |
| AU (1) | AU2016339054B2 (en) |
| CA (1) | CA3000482C (en) |
| FR (1) | FR3042509B1 (en) |
| RU (1) | RU2722026C2 (en) |
| WO (1) | WO2017064547A1 (en) |
| ZA (1) | ZA201801921B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2563641A (en) * | 2017-06-22 | 2018-12-26 | Dubai Aluminium Pjsc | Electrolysis plant using the Hall-Héroult process, with vertical magnetic field compensation |
| RU2678624C1 (en) * | 2017-12-29 | 2019-01-30 | Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" | Modular busbar for series of aluminum electrolysis cells |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU327836A1 (en) * | 1971-01-27 | 1977-12-05 | Всесоюзный Научно-Исследовательский И Проектный Институт Алюминиевой,Магниевой И Электродной Промышленности "Вами" | Installation of busbars on end face of aluminium electrolyzers |
| US4189368A (en) * | 1978-04-18 | 1980-02-19 | Vsesojuzny Nauchno-Issledovatelsky I Proektny Institut Aljuminievoi, Magnievoi I Elektrodnoi Promyshlennosti | System of busbars for aluminium-producing electrolyzers |
| FR2425482A1 (en) | 1978-05-11 | 1979-12-07 | Pechiney Aluminium | PROCESS FOR COMPENSATION OF THE MAGNETIC FIELD INDUCED BY THE NEIGHBORING LINE IN SERIES OF HIGH INTENSITY ELECTROLYSIS TANKS |
| FR2552782B1 (en) | 1983-10-04 | 1989-08-18 | Pechiney Aluminium | ELECTROLYSIS TANK WITH INTENSITY HIGHER THAN 250,000 AMPERES FOR THE PRODUCTION OF ALUMINUM BY THE HALL-HEROULT PROCESS |
| FR2583069B1 (en) * | 1985-06-05 | 1987-07-31 | Pechiney Aluminium | CONNECTION DEVICE BETWEEN VERY HIGH INTENSITY ELECTROLYSIS TANKS FOR THE PRODUCTION OF ALUMINUM, INCLUDING A SUPPLY CIRCUIT AND AN INDEPENDENT MAGNETIC FIELD CORRECTION CIRCUIT |
| NO164787C (en) * | 1988-05-11 | 1990-11-14 | Norsk Hydro As | DEVICE FOR COMPENSATION OF DAMAGING MAGNETIC EFFECT FROM LIKE RIGHT FIELD AND ENDFIELD ON TRANSFERRED ELECTROLYE OVEN IN MOLDING ELECTROLYTIC PRODUCTS OF ALUMINUM. |
| RU2168564C2 (en) * | 1999-06-03 | 2001-06-10 | ОАО "Объединенная компания "Сибирский алюминий" | Compensation device |
| CN2477650Y (en) | 2001-04-20 | 2002-02-20 | 贵阳铝镁设计研究院 | Electromagnetic interference preventing bus structure of aluminium electrolytic end tank |
| FR2868436B1 (en) * | 2004-04-02 | 2006-05-26 | Aluminium Pechiney Soc Par Act | SERIES OF ELECTROLYSIS CELLS FOR THE PRODUCTION OF ALUMINUM COMPRISING MEANS FOR BALANCING THE MAGNETIC FIELDS AT THE END OF THE FILE |
| NO322258B1 (en) * | 2004-09-23 | 2006-09-04 | Norsk Hydro As | A method for electrical coupling and magnetic compensation of reduction cells for aluminum, and a system for this |
| CN2804128Y (en) * | 2005-03-18 | 2006-08-09 | 贵阳铝镁设计研究院 | Structure of preventing magnetic field interfrence between vertical disposition tanks of aluminum electrolyzer |
| CN202064015U (en) * | 2011-04-27 | 2011-12-07 | 贵阳铝镁设计研究院有限公司 | Cell bottom output and bus configuration structure for aluminium electrolytic cell |
| CA2841300C (en) * | 2011-07-12 | 2019-04-09 | Rio Tinto Alcan International Limited | Aluminium smelter comprising electrical conductors made from a superconducting material |
| CN103114308B (en) * | 2011-11-16 | 2015-04-15 | 沈阳铝镁设计研究院有限公司 | Aluminum electrolysis tank compensation bus power supply rectification set |
| CN103114307B (en) * | 2011-11-16 | 2015-11-04 | 沈阳铝镁设计研究院有限公司 | Aluminium cell external compensation power-supply rectifying unit aluminium busbar method for arranging and system |
-
2015
- 2015-10-15 FR FR1502186A patent/FR3042509B1/en not_active Expired - Fee Related
-
2016
- 2016-10-03 EP EP16855008.5A patent/EP3362590B1/en active Active
- 2016-10-03 RU RU2018117703A patent/RU2722026C2/en active
- 2016-10-03 WO PCT/IB2016/001437 patent/WO2017064547A1/en active Application Filing
- 2016-10-03 CN CN201680060619.9A patent/CN108368624B/en active Active
- 2016-10-03 AU AU2016339054A patent/AU2016339054B2/en not_active Ceased
- 2016-10-03 CA CA3000482A patent/CA3000482C/en active Active
-
2018
- 2018-03-22 ZA ZA2018/01921A patent/ZA201801921B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU2016339054B2 (en) | 2021-06-10 |
| WO2017064547A1 (en) | 2017-04-20 |
| CN108368624A (en) | 2018-08-03 |
| EP3362590B1 (en) | 2020-04-29 |
| RU2722026C2 (en) | 2020-05-26 |
| CA3000482A1 (en) | 2017-04-20 |
| RU2018117703A (en) | 2019-11-15 |
| CN108368624B (en) | 2020-07-14 |
| FR3042509A1 (en) | 2017-04-21 |
| EP3362590A4 (en) | 2019-07-24 |
| CA3000482C (en) | 2023-08-15 |
| ZA201801921B (en) | 2019-07-31 |
| FR3042509B1 (en) | 2017-11-03 |
| EP3362590A1 (en) | 2018-08-22 |
| RU2018117703A3 (en) | 2019-12-31 |
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