EP0031307A1 - Device for conducting the current between electrolysis cells - Google Patents

Abstract

A device for conducting the electric current from the cathode of a hooded, transverse electrolytic cell to the anode of a neighboring cell via cathodically polarized carbon blocks in the pot of a cell, cathode bars and individual conductor bars wherein the current from each cathode bar is passed under a cell to a compensating conductor bar which runs around the neighboring cell. This compensating conductor bar is connected to each anode of the cell it runs around via a flexible conductor strip. Each anode is provided on its uppermost side with a yoke which is inserted and firmly secured in place, together with the conductor strip, in a notch or recess provided in a device for holding the anode in place. The anode holding device remains in place during anode changes and can be adjusted vertically by means of a motor or the like as a function of the voltage or the desired interpolar distance between anode and cathode.

Description

The invention relates to a device for guiding the current from the cathode of an optionally encapsulated and in particular transverse electrolysis furnace to the anode of an adjacent electrolysis furnace via cathodically connected carbon blocks, cathode bars and busbars (individual conductors) located in an electrolysis trough.

Known busbar guides between two transverse electrolysis furnaces conduct the furnace current from the cathode bars by means of busbars to the sides of the furnace parallel to the cathode bars and from there via connecting rails to the adjacent electrolysis oven. As a rule, the connecting rails are connected to fixed or vertically movable risers on the adjacent furnace, via which the furnace flow is fed to the movable or fixed crossmember. The furnace current flows from the traverse via anode rods to the individual anodes.

Known devices provide a wide variety of power supply options. For example, the current of all cathode bars combined in a connecting rail is fed to the riser at the next furnace. It is also known that the current is passed through one or two cathode bars under the furnace containing these cathode bars and is entered directly into the crossbeam of the adjacent furnace.

Depending on the current supply, the risers are arranged on the longitudinal or transverse sides of the furnace.

The current rail guides created in this way have considerable disadvantages. The led around the electrolysis tub Busbars and risers result in a large voltage drop, especially with wide furnace designs. Working on the furnace, in particular the replacement of the anodes with the anode rods, is considerably impeded by the risers placed on the longitudinal or transverse sides of the furnace. In addition, there is a loss of current when changing the anodes, since the current flow is not balanced. Difficulties arise again and again when short-circuiting.

Furthermore, the cathodic busbars have the disadvantage that, for purely practical reasons, they are not built in accordance with the shape required by electro-theory. This leads to equalizing currents in the busbars and also in the cathode or in the liquid bath. These equalizing currents are undesirable and have a negative effect on the furnace.

The same considerations regarding the disturbances also apply to the traverse, which acts as a current-distributing element.

The further current flow from the traverse to the anode also has considerable disadvantages. The effort to connect the anode rod and anode in the anode abutment, such as rod straightening, cleaning and welding, as well as for transportation, is very high, and handling is very accident-prone. In addition, the anode can only be replaced together with the anode rod, which in turn makes tight encapsulation of the furnace difficult. The loss of current in the anode rod itself is also not overlooked.

The inventor has set itself the goal of developing a device for conducting current between two electrolysis furnaces, which does not have these disadvantages and, above all, provides economic advantages.

The object is achieved in that individual conductors are arranged under an electrolysis furnace and an adjacent furnace, the individual conductors under the electrolysis furnace each cathode bar distant from the adjacent furnace with a compensating conductor assigned to the adjacent furnace and the individual conductors under the adjacent furnace each cathode bar near this furnace Connect the electrolysis furnace to the compensating conductor.

It is also provided that two cathode bars can be connected to a single conductor and thus connected to the compensating conductor.

In this way, the furnace flow is conducted from one furnace to the adjacent furnace in the shortest, practically feasible way.

The single conductors with the same cross-section and length result in a voltage rail guide between the two furnaces, regardless of whether each bar connection is connected to a single conductor or whether two parallel bar connections are connected to a single conductor on each side of the furnace.

The current flows, with the exception of a short-circuit in an oven, in the entire busbar system in the longitudinal direction of the hall. In practice, it has been shown that an oven which is operated with a current of approx. 160 kA and which has a busbar density of j = 0.3 -3 A / mm2, an energy saving of approx. 0.7 kWh / kg Al compared to the known conductor rail guides. This is arguably one of the most important advantages of the present invention.

With the same furnace width but different furnace lengths (different furnace sizes or furnace currents), the voltage drop always remains the same.

The disadvantages of the equalizing currents and their side effects on the furnace no longer occur with the new conductor rail system.

Advantages with regard to the magnetic bath influence result in particular from the elimination of the cathodic busbars on the longitudinal side of the furnace, the connecting rails on the transverse sides of the furnace, the risers, especially with the concentration of cathodic busbars in the corners of the furnace and the crossbar spanning the bath. On the contrary, the metal bath is exposed to an even influence, which leads to a minimization of the metal bulge.

• Die Einzelleiter weisen gleiche Länge und gleiche Querschnitte auf, was zu konstruktiven und produktionsmässigen Vereinfachungen führt.

The device according to the invention has the following design advantages:

• The individual conductors have the same length and the same cross-sections, which leads to simplifications in terms of construction and production.

Passing the furnace current with individual conductors under the furnaces results in small rail cross sections. The conductor rail guide according to the invention has no influence on the installation options for center, cross or point feeder operation. When changing the anode, there are no obstacles due to fixed risers placed on the long sides of the furnace or in the corners of the furnace.

A furnace that runs out of an ingot window causes the maximum failure of two individual conductors.

There is no obstruction of the scooping process by riser pipes at the end of the furnace.

To replace a cathode, it is only necessary to disconnect the cathode bar connections, since the removal of the anodes before lifting off the anodic part simultaneously cuts off the power supply to the anodic part.

At a current of about 160 kA and a current density of j = _O, 3 A / mm2 in the busbars about 24 tons of aluminum necessary for the inventive conductor rail guide only for the production. This means a saving of up to 35% compared to the conventional device, since the cathodic busbars on the long side of the furnace, the cathodic connecting rails on the long side of the furnace, the risers on the long sides of the furnace and / or the long sides of the furnace and / or the corners of the furnace are eliminated.

The furnace compensation conductor mentioned above is preferably arranged in a ring at the height of the trough around the electrolysis furnace. Basically, the compensating conductor, as the name implies, compensates for current flow irregularities. Among other things, it has a direct effect on the current equalization when changing the anode in the neighboring furnace and at the same time serves as a compensating conductor for the cathode of the electrolysis furnace. Therefore there is no loss of power when changing the anode.

The compensating conductor also serves as a current guide rail during the short-circuiting of the neighboring furnace. It can also be used to place the work surface around the stove.

As one of the most important advantages, the compensating conductor enables the connection to the anode via a flexible current band, which is preferably attached as close as possible to the anode. For this purpose, the anode is advantageously provided according to the invention with a current-conducting yoke, which is easily detachably connected to the anode holder and the current band.

When changing the anode, only the remaining piece of the burned-off anode with the yoke is separated from the anode holding device. This anode design considerably facilitates the transportation of the anode from and to the anode striking station. The previously common cause of accidents due to falling anode rods is eliminated. Overall, the handling of the anode is made considerably easier.

The anode width itself is preferably chosen so that it corresponds to twice the width of a carbon block element. The furnace current thus flows from two individual conductors to an anode of the subsequent cell.

This anode design enables the anode holding device to remain on the furnace and, for example, to be fixed to the crossbar. This results in the possibility of a continuous vertical up and down movement of the anode holder by means of a motor, a hydraulic, a pneumatic or the like drive. The vertical movement follows the erosion at the anode evenly, so that the cheapest interpolar distance is always maintained between anode and cathode. This eliminates the anode measurement.

According to the invention, the control unit of this vertical movement is a computer which receives the current data from the anode and cathode and compares them with setpoints. If the voltage rises above a certain limit, the interpolar distance is automatically reduced by lowering the anode.

If the anode has burned down completely or down to a remnant, the anode holder is set in motion vertically upwards, this process preferably being interrupted after the anode remnant has been pulled out of the crust. In the case of encapsulated ovens, the crust is given time to close without emissions escaping into the hall. Only when the crust has completely closed is the anode remnant removed further. Since the encapsulation in ovens can advantageously be very tight with this current routing and this design of the anode holding device, the environmental pollution caused by the exhaust air is reduced to a minimum. The encapsulation preferably consists of hinged plates or the like. Plates, each anode being assigned its own cover plate. By lifting the anode remnant, this plate is opened, while the rest of the furnace remains covered.

To change the anode, first remove the current band and then lift the yoke out of its anchoring with the anode holding device.

There are various possibilities for the connection between the anode holding device and the yoke or current band. So can For example, the anode holding device consists of two elements that can be moved axially relative to one another or into one another, wherein one of the elements has a notch in or over which the other element is moved, with which a clamping effect can be achieved.

For example, a notch on a notch, into which the yoke of the anode and the current band is inserted, it has proven to be favorable to place a clamping sleeve with an internal thread on the holding bar. After inserting the yoke and the current band, this clamping sleeve is rotated over the notch and thus clamps the yoke and current band.

Another holding possibility is provided if a sleeve is fastened to the crossmember, which has an indentation in its end region remote from the crossmember, in which the yoke and current band are placed. The yoke and current band are fixed by inserting a pressed wood into the sleeve.

The clamping sleeve or pressing bolt can preferably be moved by means of a pneumatic, hydraulic or motor device.

However, these options for the connection between the anode holder and the anode are only examples.

• Fig. 1 einen Querschnitt durch eine Reihe von quergestellten Elektrolyseöfen;
• Fig. 2 eine schematische Darstellung der Stromführung zwischen Elektrolyseöfen
• Fig. 3 eine weitere Ausführungsform nach Fig. 2;
• Fig. 4 ein Detail aus Figur 1;
• Fig. 5 einen Querschnitt nach Linie V - V in Fig. 4
• Fig. 6 eine weitere Ausführungsform nach Fig. 5.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

• 1 shows a cross section through a series of transverse electrolysis furnaces.
• Fig. 2 is a schematic representation of the current flow between electrolysis furnaces
• Fig. 3 shows a further embodiment according to Fig. 2;
• 4 shows a detail from FIG. 1;
• 5 shows a cross section along line V - V in FIG. 4
• 6 shows a further embodiment according to FIG. 5.

A trough 11 of an electrolysis furnace 10 is lined with insulating material 12 at the bottom and with coal edge blocks 13 at the edge. Cathodically connected carbon blocks 30 are supported on the insulating material 12, from which the current is derived in the direction x via cathode bars 31, 32.

Aluminum 15 deposited from an electrolyte 14 collects on the carbon blocks 30.

Anodes 16 are immersed in the electrolyte 14 and are attached to a cross member 18 via anode holding devices 17.

Between adjacent anodes 16 there is an impact device 19 for impacting crust 20 formed on the electrolyte.

The tub 11 is encapsulated with the cover plate 22 articulated on the cross member 18 by means of a piano hinge 21.

Individual conductors (busbars) 33, 34 are connected to the cathode bars 31, 32, the individual conductor 33 passing the current of the cathode bar 31 distant from an electrolytic furnace 10a under the electrolysis furnace 10, the individual conductor 34 passing the current from the cathode bar 32 near the electrolysis furnace 10a Electrolysis furnace 10a leads through. 50% of the current of a cathodically connected coal block 30 thus flows through each individual conductor 33, 34.

In the electrolysis furnace 10a, the individual conductors 33, 34 are connected to a compensating conductor 35 surrounding them. The current rail guidance from the cathode of the electrolysis furnace 10 to the compensating conductor 35 of the furnace 10a is carried out for each coal block 30 or for each cathode bar 31, 32 of the furnace 10. If the furnace 10 a is short-circuited, the compensating conductor 35 serves as a current guide rail at the connection points 40. Further short-circuit points are designated by 42, 43.

A first gradation of the electrical furnace calcination is achieved in that the individual conductors 33, 34 are short-circuited at points 42, 43.

A second electrical gradation for the furnace calcination is achieved by short-circuiting the furnace at the connection points 40.

From the compensating conductor 35 of the furnace 10a, the current is supplied to the anodes 16 via preferably flexible current strips 36 and from the anodes 16 of the furnace 10a via its cathode to a next furnace 10b in the manner described.

The anodes 16 are fixed to the anode holding device 17 by means of a yoke 38.

4, 5 consists of a holding rod 23, around which a clamping sleeve 24 with an internal thread is movably arranged. The end of the holding rod 23 facing the anode 16 has a notch 25, in which the yoke 38 is hung and the current band 36 is inserted. To clamp yoke 38 and band 36, the clamping sleeve 24 is rotated downward.

A further possibility of fixing the yoke 38 and the current band 36 to the anode holding device 17 provides, according to FIG. 6, a sleeve 26 with an internal thread, in which a pressing bolt 29 with an external thread, preferably movable via a motor or the like. 27 and a gear mechanism 28, is guided. The sleeve 26 has a notch 25a into which the yoke 38 and the current band 36 are inserted. Both are clamped by turning the pressing bolt 29.

The anode width is preferably chosen so that it corresponds to twice the width of a coal block 30. The furnace current thus flows from two individual conductors 33 and 34 to an anode 16.

However, two cathode bars 31 and 32 can also be joined together on a longitudinal side of the furnace 10 as shown in FIG. 3 and routed to the compensation conductor of the furnace 10a.

Accordingly, two coal blocks 30 each with two individual conductors 33 and 34 and two anodes 16 form a unit, which can result in different furnace ^g sizes lined up as desired.

The work surface 41 is located between two electrolysis furnaces 10.

Claims (10)

1. Device for guiding the current from the cathode of an optionally encapsulated and, in particular, transverse electrolysis furnace to the anode of an adjacent electrolysis furnace via cathodically connected carbon blocks, cathode bars and current rails (individual conductors) located in an electrolysis trough, characterized in that under an electrolysis furnace (10) and one Adjacent furnaces (10a) individual conductors (33, 34) are arranged, the individual conductors (33) under the electrolysis furnace (10) each cathode bar (31) remote from the neighboring furnace (10a) with a compensating conductor (35) assigned to the neighboring furnace (10a) ) and the individual conductors (34) under the adjacent furnace (10a) connect each cathode bar (32) of the electrolysis furnace (10) close to this furnace (10a) to the compensating conductor (35). 2. Device according to claim 1, characterized in that the compensating conductor (35) is arranged in a ring at tub height around the electrolysis furnace. 3. Device according to claim 1 or 2, characterized in that from the compensating conductor (35) to the anodes (16) or to the anode devices (17) connected to the anodes (16) via a yoke (38), flexible current strips (36) to lead. 4. The device according to claim 3, characterized in that the anode holding device (17) is fixed to a crossmember (18) and remains on the furnace when changing the anode. 5. The device according to claim 3 or 4, characterized in that the anode holding device (17) has an arrangement (25) for receiving the yoke (38) and the current band (36). 6. The device according to claim 5, characterized in that the receiving arrangement (25) consists of a notch which allows jamming of the yoke (38) and current band (36). 7. The device according to at least one of claims 4 to 6, characterized in that the anode holding device (17) has two elements (23, 24 or 26, 29) which can be moved axially relative to one another or into one another. 8. The device according to claim 7, characterized in that the movable elements a holding rod (23) and a surrounding clamping sleeve (24) with an internal thread, or that the movable elements are a sleeve (26) with an internal thread and a press bolt guided in this (29 ) are. 9. The device according to at least one of claims 4 to 8, characterized in that the holding rod (23) or sleeve (26) have the arrangement (25) for receiving the yoke (38) and the current band (36). 10. The device according to claim 9, characterized in that the clamping sleeve (24) or the pressing bolt (29) at least partially engage in the arrangement (25) for clamping.

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