DE1059192B - Electrolysis furnace of at least 40,000 A for the fused-salt electrolysis of aluminum - Google Patents

Description

In an effort to increase the profitability of aluminum production, ever larger electrolysis furnaces are being built in the aluminum industry, which today are intended for currents of up to 100,000 A. Experience has shown, however, that in electrolysis furnaces with high currents there are electromagnetic forces of such magnitude that the operation of the furnace can be severely disturbed. Such malfunctions can already occur in ovens of 40,000 ¹ A; they can be used in ovens with high amperage, e.g. B. 100,000 A, so large that a normal operation is no longer possible. These electromagnetic forces are created by the interaction of the current flowing through the electrolysis furnace and the magnetic fields in the furnace. They affect metal bulges and bulges, which can lead to a too hot furnace corridor and a sharp drop in the current yield. The force effects are greatest when the magnetic field and the streamlines are directed perpendicular to each other; that is, the flashes and metal currents are greatest when the field has, for example, vertical components that cut through the metal and the flow has horizontal components in the metal, and when these components are asymmetrically distributed over the furnace.

It has already been proposed to avoid the creation of horizontal flow components in the metal the horizontal current conductors (cathode bars) embedded in the carbon base to isolate electrically at their ends or to form them bent and so in the carbon base embedded so that the ends leading out of the furnace are lower than the central part.

According to a further suggestion, the current leads are led out vertically from the furnace floor and connected to horizontal power line rails that run below the furnace floor will. In order to achieve that the magne- * o table field in the metal strip is as small as possible, the horizontal anode feeds and Cathode leads are arranged as equally and as large as possible above or below the furnace.

However, compliance with the construction principles mentioned has not yet been completely successful guided. The insulation of the ends of the cathode beams is made by the action of heat and by the excavation of the soil in the company prematurely destroyed. The curved design of the cathode bars and the vertical lead out of the current leads also do not lead to success, if not at the same time it is ensured that no asymmetrical

for melt electrolysis

of aluminum

Applicant:

Aluminum Industry Shares Society Chippis, Valais (Switzerland)

Representative: Dr. K. Schwarzhans, patent attorney.
Munich 19, Romanplatz 9

Claimed priority:
Switzerland from July 9, 1955

Dipl.-Ing. Hans Schmitt, Rheinfelden (Bad.),

and Dr. Paul Müller, Pully, Waadt (Switzerland),

have been named as inventors

Irish vertical field in the furnace's melting chamber arises. It has also been found that it is inconvenient to use the horizontal power line rails to run along under the stove, because a series of z. B. two adjacent rows of Electrolysis furnaces form a current loop with a relatively strong magnetic inside A field arises which is superimposed on the field which each furnace forms for itself and which cuts through the furnaces The vertical components of the magnetic field of this current loop become larger, the more lower the current leads from furnace to furnace are arranged lower half of the furnace floors.

It is known that 'with a horizontal position of the power line rails along the side next to the furnace pan the magnetic field created by the conductors saturates the iron furnace shell causes. This in turn creates discontinuous fields, which interact with horizontal Electricity components in the metal cause electromagnetic forces. "

Investigations have now shown that in the case of electrolysis furnaces for the melt flow electrolysis of Aluminum with embedded horizontally in the carbon bottom straight cathodic power supply rails (cathode bars) the ■ harmful. effects the electromagnetic forces on the bath can thereby be prevented; that the out Parts of the current leads leading out into the furnace

909530/350

Claims (6)

3 4 be placed deeper than that in the coal soil in which is influenced, but that at the same time through the Zone below the anode embedded horizontal -. ' Leadership of the cathode leads in contrast to Part and that they with outside of the furnace parallel to the known embodiments also the magnedessen Power line rails lying longitudinally in the inner field of the furnace and connected to it that are so deep that 5 superimposed, through the adjacent furnace their Upper edges at most at the same height as the rows formed field is aligned so that only Lower edge of the furnace shell are, preferably still very small, evenly distributed vertical ones 1 m deeper than this, but not more than 2 m. Field components can arise in the furnace. As a result The horizontal part of the cathode bar that underlies the arrangement of the horizontal power lines the anode runs, must not be more than 10 rails laterally below the furnace jacket is a 0.5 m over the outer side surfaces of the anode or excessive magnetic saturation of the same avoided, protrude from the anode group, because that from the anode and at the same time is achieved by this arrangement, or anode group, furnace flux and metal that flowing through the current loop of the furnace rows Electricity is said to be directed towards the part of the cathode formed vertically within the furnace be concentrated, which is under the anode. Before 15 is inclined considerably so that the vertical field is partially the ends of the cathode bar with components in the furnace should be considerably weakened. the planes of the side surfaces be flush, as in the drawing are three exemplary embodiments 1 and 2 shown. Fig. 3 shows the most important of the invention. permissible protrusion by 0.5 m. This limitation applies. Fig. 1 shows a cross section through an electrical generally for the border line of the horizontal 20 lysis furnace with downward cranked cathode bars, talsurface, which is divided by the horizontal, under that which runs under the anode and the Anode or anode group arranged parts of the lateral current leads arranged horizontally Cathode bar is ingested. Those among the are. Top sides of the anode or anode group lying Fig. 2 and 3 show electrolysis furnaces with vertical the outermost cathode bars must not exceed 0.5 m 25 cathode discharge in cross section, arranged outside the plane of the side surfaces. The tub 1 of the electrolytic furnace is provided with a be. ■ Lined Koihle floor. Above is the anode 2 The invention now relates to an electrical with the vertical power supply 3 arranged: lysis furnace of at least 40,000 A for the melt - it dips into the melt 4. The carbon bottom inflow electrolysis of aluminum with horizontal at 3 ° is made of carbon blocks 5. The edges 6 are made of the carbon bottom embedded, under the anode or coal rammed mass. The carbon blocks 5 are under the anode group flat cathode - - ^; in the usual way on their lower side with bars, in which electrolysis furnace the horizontal part of the cathode bars 7, 10, 13 running under a longitudinal groove is embedded in which the cathode-anode runs.
bars not more than 0.5 m laterally over the outer 35. In the furnace according to FIG. 1, the ends 8 of the cathode side surfaces of the anode or the anode group are in front of bars 7 at the point where they exit the carbon from the furnace Outwardly extending parts of the "· blocks 5, ie at the point which are lower under the lower current conductors than the one below the longitudinal edge of the anode, bent downwards the current leads with outside of the ends 8 are lower than the part lying parallel to the longitudinal axis of the anode in the carbon block 5 under the furnace. that their upper edge is connected at most to the same line rails 9, which are arranged on the side of the furnace as high as the lower edge of the furnace shell, but not deeply nd that their upper edge is lower, more than 2 m lower than this. +5 as the lower edge of the furnace pan 1. In the electrolysis furnace according to FIG. 2, the cathodes are preferably lower than the lower edge of the furnace shell. bar 10 only as long as the anode 2 is wide. she The horizontal cathode bars can be provided with three vertical current conductors 11 at their outlet from the part of the bound lying under the anode, which in turn goes over the horizontal rail 12 Carbon bottom be bent down so that the 50 with the side power line rails 9 in Verhorizontalen The ends leading out of the oven are deeply bound. than the middle part lying under the anode. In the electrolytic furnace according to Fig. 3 are across the width You can connect the cathode bar to the furnace with two separate cathode bars Leads built from three welded parts 13, the vertical current leads Manufacture by placing the ends of the central horizontal 55 14 and horizontal ones under the furnace floor zontal section on the outer end of the two rails 15 with the lateral power line rails 9 welded on horizontal current conductors. are connected. According to a further embodiment of the invention point the cathode bars vertically downwards from claims: the furnace emerging line ^{sections, the 6o} over horizontal rails with the outside of the 1st electrolysis furnace of at least 40 000 A for Electricity lying parallel to the longitudinal axis of the furnace - the molten nut electrolysis of aluminum line rails are connected. horizontally embedded in the coal floor, under In the furnace according to the invention, at least the anode or below the anode group 40,000 A occur even in a furnace series of two cathode bars running next to each other, characterized by rows running next to each other, no metal marks that the flashes running under the anode more occur, and the furnace works with high horizontal part (7, 1O ₁ 13) of the cathode bar Stromausbeufe. This is due to the fact that in the arrangement according to the invention not only the side surfaces of the anode (2) or the anode current curve in the melting chamber of the furnace does not protrude more than 0.5 m laterally from the outer side, which is from out of the oven- the parts (8,12,15) of the current leads deeper lie than the horizontal parts of the cathode bars running below the anode and the Current conductors with conductor rails lying outside the furnace parallel to its longitudinal axis (9) are connected, which are arranged so deep that their upper edge is at most at the same level as the lower edge of the furnace shell (1), but not more than 2 m lower than this. 2. Electrolysis furnace according to claim 1, characterized in that the power line rails (9) 1 m lower than the lower edge of the furnace shell (1). 3. Electrolysis furnace according to claim 1 or 2, characterized in that the horizontal Cathode bar (7) as it emerges from the part of the carbon base lying under the anode (5) are bent downwards so that the horizontal ends (8) leading out of the furnace lower than the part under the anode. 4. Electrolysis furnace according to claim 1, characterized in that the one extending under the anode horizontal part (7) of the cathode bar at its ends overlapping the ends of the parts (8) leading out of the furnace are welded on is. 5. Electrolysis furnace according to claim 1, characterized in that the horizontal, under the Anode (2) or the anode group running part (10) of the cathode bar through downwards Line sections (11) emerging from the furnace (1) via horizontal rails (12) with the power line rails (9) lying outside the furnace parallel to its longitudinal axis connected is. 6. Electrolysis furnace according to claim 1, characterized in that the one extending under the anode horizontal part of the cathode bar consists of two parts (13), each in one of the Charcoal blocks forming the furnace bottom are embedded and each through one down from the furnace emerging line section (14) via a horizontal rail (15) with the outside of the Oven parallel to its longitudinal axis lying power line rails (9) are connected. 1 sheet of drawings © 909 530/350 6.59