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WO2013068412A2 - Bloc cathodique à face supérieure bombée et/ou arrondie - Google Patents

Bloc cathodique à face supérieure bombée et/ou arrondie Download PDF

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Publication number
WO2013068412A2
WO2013068412A2 PCT/EP2012/072046 EP2012072046W WO2013068412A2 WO 2013068412 A2 WO2013068412 A2 WO 2013068412A2 EP 2012072046 W EP2012072046 W EP 2012072046W WO 2013068412 A2 WO2013068412 A2 WO 2013068412A2
Authority
WO
WIPO (PCT)
Prior art keywords
cathode block
groove
cathode
regions
section
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.)
Ceased
Application number
PCT/EP2012/072046
Other languages
German (de)
English (en)
Other versions
WO2013068412A3 (fr
Inventor
Thomas Frommelt
Arash RASHIDI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SGL Carbon SE
Original Assignee
SGL Carbon SE
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by SGL Carbon SE filed Critical SGL Carbon SE
Priority to JP2014540439A priority Critical patent/JP2014532816A/ja
Priority to EP12786943.6A priority patent/EP2776608A2/fr
Priority to CA2854928A priority patent/CA2854928A1/fr
Priority to IN3395CHN2014 priority patent/IN2014CN03395A/en
Priority to CN201280055341.8A priority patent/CN103958740A/zh
Publication of WO2013068412A2 publication Critical patent/WO2013068412A2/fr
Publication of WO2013068412A3 publication Critical patent/WO2013068412A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes

Definitions

  • the present invention relates to a cathode block which is particularly suitable for use in an electrolytic cell for the production of aluminum.
  • Electrolysis cells are used, for example, for the electrolytic production of aluminum, which is usually carried out industrially by the Hall-Heroult process.
  • a melt composed of aluminum oxide and cryolite is electrolyzed. It serves the Hall-Heroult process
  • the electrolytic cell used in this method has a cathode bottom, which may be composed of a plurality of adjacent, forming the cathode cathode blocks.
  • the cathode is usually composed of a carbonaceous material.
  • grooves are usually provided, in each of which at least one bus bar is arranged, through which the current supplied via the anodes is removed.
  • layer of liquid aluminum is formed, in particular of individual anode blocks formed anode, between the and the surface of the aluminum, the electrolyte, ie the Alumina and cryolite-containing melt is located.
  • the aluminum formed is deposited below the electrolyte layer due to its greater density compared to that of the electrolyte, ie as an intermediate layer between the upper side of the cathode and the electrolyte layer.
  • the dissolved in the melt aluminum oxide is split by electric current flow to aluminum and oxygen.
  • the layer of liquid aluminum is the actual cathode because aluminum ions are reduced to elemental aluminum on its surface.
  • the term cathode will not be understood below to mean the cathode from an electrochemical point of view, ie the layer of liquid aluminum, but rather the component forming the base of the electrolytic cell, for example composed of one or more cathode blocks.
  • a major disadvantage of the Hall-Heroult process is that it is very energy intensive. To produce 1 kg of aluminum about 12 to 15 kWh of electrical energy is needed, which accounts for up to 40% of the manufacturing cost. In order to be able to reduce the production costs, it is therefore desirable to reduce the specific energy consumption in this process as much as possible.
  • the driving force for the formation of waves in the layer of liquid aluminum is the inhomogeneous distribution of the electric current density and the magnetic flux density over the surface of the cathode, which leads to a corrugating distribution of the Lorentz force density in the layer of liquid aluminum.
  • the Lorentz force density is defined as the vector product of the electrical current density present at a specific location and the magnetic flux density present at this location.
  • the Cathode and in the aluminum bath preferably follows the path of least electrical resistance.
  • the electric current flowing through the cathode typically concentrates primarily on the lateral edge regions of the cathode, at which the connection of the cathode with the busbars contacting the latter takes place, since the resulting electrical resistance in the flow of current across the edge regions to the surface of the Cathode is lower than the current flow through the center of the cathode to the surface of the cathode, in which a longer path or electrical path must be covered as in the flow of current over the edge regions to the surface of the cathode.
  • the inhomogeneous current density distribution and in particular the increased current density at the lateral edge regions of the cathode viewed in the transverse direction of the cathode, also increase in comparison with the current density in the center of the cathode an increased wear of the cathode in the lateral edge regions, which typically leads after prolonged operation of the electrolytic cell to a characteristic in cross-section of the cathode about W-shaped wear profile of the cathode.
  • electrolysed cells with profiled surface cathodes, for example those whose upper side, viewed in cross-section of the cathode, is in the form of a V-shaped well are.
  • the depression formed in the form of a V-shaped well in the cathode surface causes the current density in the lateral edge regions of the cathode to be reduced, thereby reducing the wave formation potential and also the wear in these regions.
  • cathodes are used, the upper side of which contain a recessed central area, wherein this recessed area can have a certain volume A. These pits have sloped surfaces, i. they are in the form of tubs.
  • these cathodes and the cathode blocks composing these cathodes also do not solve the wave formation and wear problems satisfactorily.
  • the object of the present invention is therefore to provide a cathode block which, when used in a fused-salt electrolysis in an electrolytic cell, causes a reduced specific energy consumption and has an increased service life.
  • a cathode block is to be provided which allows the thickness of the melt layer between the aluminum and the anode to be reduced in the electrolysis cell without causing instabilities, such as short circuits or reoxidations of the formed layer, in the layer of liquid aluminum as a result of increased wave formation tendency Aluminum or fluctuations of the electrolysis cell voltage occur.
  • this object is achieved by providing a cathode block, in particular for an aluminum electrolytic cell, having the features of claim 1 with at least one arranged on one of the sides of the cathode block and extending in the longitudinal direction of the cathode block groove for receiving a Conductor rail, wherein at least a portion of the surface of the at least one groove side having opposite side of the cathode block, as seen in cross section of the cathode block, arcuately outwardly curved, wherein the vertex of the at least one arcuate outwardly curved section, based on the in the cross section of the cathode block perpendicular to the at least one groove having side extending direction over which at least one groove is arranged.
  • Sections on the top of the cathode block is adjusted and thereby the length of the electrical path of least resistance, which leads from the upper edge of the groove to the vertically above the groove arranged portion of the top of the cathode block, to the length of the electrical paths of the larger resistances is adjusted from the lower edge of the cathode block next to the portion comprising the groove of the bottom of the cathode block lead to the top of the cathode block.
  • the length of the electrical path between the upper edge of the groove of rectangular cross-section centered at the bottom of the cathode block and the portion vertically above it on the upper side of the cathode block is substantially shorter than the lengths of the electrical paths.
  • the cathode surface assumes a wave-like shape, which can lead to increased wave formation in the layer of liquid aluminum arranged on the cathode block. Due to the embodiment of the cathode block surface according to the invention, the electrical path between the upper side of the groove and the cathode surface is increased and reduced between the side surface of the groove and the cathode surface.
  • the distance between the anode and the layer of liquid aluminum can be reduced, resulting in additional energy savings in the operation of an electrolytic cell comprising the cathode block. It is particularly advantageous that the above-described measure used to equalize the electric current density on the cathode top, namely the provision of at least one arcuate outwardly curved portion, can be easily sized so that the cathode block according to the invention can be used in an electrolysis cell in that the same bath volume results-even with a reduced distance between the anode and the layer of liquid aluminum-as with the use of a conventional cathode.
  • the intersecting curve defined by the cathode surface in the cross-section of the cathode block is, as seen in the cross-section of the cathode block, curved outwards in an arcuate manner, as seen in the cross-section of the cathode block, with a convex edge facing outward with respect to the cathode block
  • Curvature comprises, wherein a curved section is a section of the cutting curve in which the direction changes continuously, but without that in the curved area an angular or angular or angular change in direction is present.
  • verex of a curved portion in the present invention refers to the farthest point of the curved portion as seen perpendicularly from the bottom of the cathode block.
  • the cathode block is constructed on the basis of carbon and / or graphite, wherein the cathode block is particularly preferably at least 30 wt .-%, more preferably at least 40 wt .-%, particularly preferably at least 50 wt .-%, very particularly preferably at least 60% by weight and most preferably entirely composed of carbon and / or graphite.
  • the carbon is amorphous carbon and the graphite is preferably graphitic or graphitized carbon. It is further preferred that mixtures of amorphous carbon and graphitic carbon, amorphous carbon and graphitized carbon, amorphous carbon, graphitic and graphitized carbon, or graphitic and graphitized carbon are used.
  • the cathode block has exactly one groove for receiving bus bars, preferably a bus bar, with a rectangular cross-section, preferably at least that, relative to the cross-section of the cathode block perpendicular to the side having the groove extending direction, over the groove lying portion of the groove side facing the opposite side of the cathode block is curved arcuately outward.
  • the lengths of the electrical paths between the upper edge of the groove and the regions of the surface of the cathode block arranged vertically above the groove on the one hand and the adjacent areas of the surface of the cathode block on the other hand are unified, so that the cathode block in the Use in an electrolytic cell has - seen over its surface - homogeneous current density.
  • the cathode block can also have two grooves for receiving busbars, preferably in each case one current busbar. rail, each having a rectangular cross-section, wherein at least the, relative to the cross-section of the cathode block perpendicular to the grooves having the side extending direction (z), lying over the grooves portion of the side facing the two grooves side of the cathode block once curved arcuately outwards, or, wherein each of the two, relative to the cross-section of the cathode block perpendicular to the side having the two grooves extending direction over the grooves lying portions of the side facing the two grooves side of the cathode block arcuate outwardly is curved, wherein each of the vertexes of the two arcuate outwardly curved portions, relative to the cross-section of the cathode block perpendicular to the direction of the two grooves having side extending direction, disposed over in each case one of the two grooves.
  • the lengths of the electrical paths between the upper edge of each nearest groove and the vertically disposed areas of the surface of the cathode block on the one hand and the adjacently disposed areas of the surface of the cathode block on the other hand unified, so that the cathode block at the use in an electrolytic cell has a - seen over its surface - homogeneous current density.
  • the cathode block has two grooves for receiving busbars, preferably in each case a busbar, each having a rectangular cross-section, preferably at least the, relative to the cross-section of the cathode block perpendicular to the side having the grooves Direction, over the grooves lying portion of the side facing the grooves of the opposite side of the cathode block is curved once arcuately outwards, so there is an arcuate outwardly curved portion on the cathode top, which spans the two grooves.
  • the range of 20 to 80% of the width of the groove, the portion of the groove, which viewed in the cross section of the cathode block, at 20% of the measured from a lateral end of the groove in the width direction of the cathode block extension of the groove begins and at 80% of from this lateral end of the groove ends in the width direction of the cathode block measured extension of the groove ends.
  • the center of the groove is understood to be the point which, viewed in cross-section of the cathode block, is arranged in the center of the groove, ie 50% of the extension of the groove measured from a lateral end of the groove in the width direction of the cathode block.
  • the at least one arcuately outwardly curved region of the surface of the cathode block cover at least 20%.
  • the at least 40% is arranged over at least 40%, more preferably over at least 60%, most preferably over at least 80% and most preferably over 100% of the range extending, based on the cross-section of the cathode block perpendicular to the at least one groove having side Direction, is arranged over the width of the groove.
  • the at least one arcuately outwardly curved region of the surface of the cathode block be at least 20%, preferably at least 40 %, more preferably over at least 60%, and most preferably over at least 100%, of the cross-section of the cathode block extending from the side of the cathode block opposite the at least one groove.
  • the cathode block surface viewed in the cross section of the cathode block preferably has exactly one curved area which fulfills the values described above with respect to the width of the cathode block.
  • the cathode block surface, viewed in cross-section of the cathode block preferably has a curved region spanning the two grooves, which fulfills the values given above with respect to the width of the cathode block, or has two curved portions which, taken together, satisfy the values given above with respect to the width of the cathode block.
  • a comprehensive homogenization of the distribution of the electric current density results in the context of the invention in particular when the at least one arcuate outwardly curved portion of the surface of the cathode block, for example over at least 60%, preferably over at least 80%, more preferably over at least 90% and most preferably extends over at least 100% of the length of the cathode block.
  • a particularly well adapted to the electrical flow conditions in the cathode block when using the same in an electrolytic cell cathode surface is achieved according to a further embodiment of the first aspect of the present invention, characterized in that the at least one arcuate outwardly curved portion of the surface of the cathode block, based on the cross section of the cathode block, oval-segment-shaped, in particular circular-arc-shaped, cosinusoidal, in the form of a Gaussian normal distribution, elliptical-segment-shaped, curved in the shape of a Bezier curve, parabolic section-shaped or in the form of a cosine curve of higher power.
  • the at least one arcuately outwardly curved portion of the surface of the cathode block be symmetrical to the mid-perpendicular plane of the at least one groove relative to the cross section of the cathode block is. This also achieves easy manufacturability of the cathode block and universal applicability of the cathode block in an electrolysis cell.
  • the cathode block surface in such a way that the at least one arcuate outwardly curved portion the shape of an ellipse segment with a width of the interval of the polar angle between 10 ° and 180 °, preferably between 30 ° and 160 °, more preferably between 50 ° and 140 ° and very particularly preferably between 70 ° and 120 °, and / or that the at least one arc-shaped curve curved outward has the shape of a cosine curve having a width of the interval of the angle between 10 ° and 180 °, preferably between 30 ° and 160 °, more preferably between 50 ° and 140 ° and most preferably between 70 ° and 120 °, and or that the
  • the quotient of the distance from the vertex of the at least one arcuately outwardly curved portion of the surface of the cathode block to the lowest point of the groove and the distance from the lowest point of the groove the side of the cathode block opposite the at least one groove side to the lowest point of the groove between more than 1: 1 to at most 2: 1, preferably 1, 0 to
  • the at least one groove be at least 40%, preferably at least 60%, more preferably at least 80%, most preferably at least 90%, and most preferably above entire length of the cathode block extends.
  • the at least one groove in particular rectangular in cross-section, has a depth varying over its length, the at least one groove particularly preferably has a smaller depth at its longitudinal ends than in its center.
  • the groove can in particular have a course approximately triangular in longitudinal section of the cathode block.
  • Cathode blocks to achieve a uniform distribution of the electric current density at the cathode block surface when it is used in an electrolytic cell it is preferred if the surface of the side facing the at least one groove side, viewed in longitudinal section of the cathode block, is designed trough-shaped. It is particularly preferred when the cathode block is configured with the trough-shaped surface according to the second aspect of the present invention described below. In this respect, the advantageous embodiments and advantages described below in relation to the second aspect of the present invention also apply correspondingly to the first aspect of the present invention.
  • a cathode block for an aluminum electrolytic cell which has a trough-shaped surface viewed in a longitudinal section of the cathode block, wherein the trough has two edge regions and a, seen in the longitudinal direction of the cathode block, arranged between the edge regions and lowered relative to the edge regions bottom region, wherein between the two edge regions and the bottom region in each case a corresponding edge region and the bottom region connecting side wall region is provided, wherein at least one of the two connection regions between the Edge regions and the side wall portions and / or at least one of the two connecting portions between the bottom portion and the side wall portions is arcuately curved, wherein the at least one arcuately curved portion has a length of more than 2 cm.
  • the cathode block is based on carbon and / or graphite, wherein the cathode block is particularly preferably at least 30 wt .-%, more preferably at least 40 wt .-%, particularly preferably at least 50 wt. %, more preferably at least 60% by weight and most preferably entirely composed of carbon and / or graphite.
  • the carbon is amorphous carbon and the graphite is preferably graphitic or graphitized carbon. It is further preferred that mixtures of amorphous carbon and graphitic carbon, amorphous carbon and graphitized carbon, amorphous carbon, graphitic and graphitized carbon, or graphitic and graphitized carbon are used.
  • the trough-shaped surface is preferably the surface of the cathode block, which is arranged opposite the surface of the cathode block which has the at least one groove for receiving busbars, preferably in each case one busbar.
  • the trough-shaped surface of the cathode block according to the invention is located on the - im
  • the cathode block in an electrolytic cell - top of the cathode block that is the side of the cathode block on which the layer of liquid aluminum is provided.
  • an arcuately curved configuration of at least one of the connection regions of a trough-shaped cathode block ie by an arcuately curved configuration of at least one of the connection regions which are provided between the edge regions and the sidewall regions and between the bottom region and the sidewall regions in that the electric current density and the magnetic flux density are made uniform in the use of the cathode block in an electrolytic cell.
  • the current - in contrast to a cuboid cathode block - not primarily flows in the lateral edge regions of the cathode block, but the current flow, because in the trough-shaped configuration realized as described above, the electrical resistance of the edge regions due to greater height of the edge areas is increased in relation to the height of the bottom area with respect to the electrical resistance of the bottom portion of the cathode block, is homogeneously distributed over the surface of the cathode block. This, in turn, is a consequence of the fact that the current in the cathode block follows the path of least electrical resistance.
  • At least one of the connecting regions is achieved by the arcuately curved configuration that no inhomogeneously distributed current densities occur even in the region of the at least one connecting region, which runs at an angle in a trough-shaped configuration known from the prior art. Rather, the arcuately curved configuration, the occurring during the use of the cathode block in an electrolytic cell at the surface of the cathode block distribution of electric current density is compared in comparison to a cathode block with a winkeligen design even in the connecting areas, so that wave formation in the layer of liquid aluminum during operation of the electrolytic cell and concomitant instabilities of the electrolysis operation can be effectively avoided.
  • an arcuate portion is understood to mean a portion where the sectional curve defined in the cross section of the cathode block by the cathode surface has a convex curvature with respect to the cathode block interior, with a portion below the curved portion Intersection curve is understood, in which the direction changes continuously, but without that in the curved area an angular change in direction is present.
  • the length of the arc-shaped curved section in the sense of the present invention designates the extension, measured in the longitudinal direction of the cathode block, of the arc-shaped curved section from its beginning up to its end, ie from the point of transition of the preferably rectilinear edge region in the arcuately curved connecting portion to the point of its transition into a preferably rectilinear portion of the side wall portion or from the point of transition of a preferably rectilinear portion of the side wall portion in the arcuately curved connecting portion to the point of its transition into the preferably rectilinearly shaped bottom portion.
  • the at least one arcuately curved section has a length of more than 2 cm to 100 cm, preferably 3 to 50 cm, particularly preferably 4 to 30 cm, particularly preferably 5 to 20 cm, most preferably from 7 to 15 cm and most preferably 10 cm, since peaks or valleys of the electric current density above the curved portion are particularly reliably avoided by such a dimensioning of the curved portion.
  • the arcuate portion is preferably arcuately curved inwardly with respect to the cathode block as viewed in the longitudinal section, whereas if the arcuate portion Section is provided in at least one of the connecting portions between the edge regions and the side wall portions of the trough-shaped surface of the cathode block, preferably outwardly arcuately curved.
  • At least one of the two connection regions is between the bottom region and the side wall regions and are preferably both connection regions between the bottom region and the side wall regions, with respect to the cathode layer considered in longitudinal section. block, designed curved inwards in an arcuate manner.
  • at least one of the two connection regions between the edge regions and the sidewall regions and preferably both connection regions between the edge regions and the sidewall regions are / is configured outwardly arched with respect to the cathode block viewed in longitudinal section.
  • a particularly advantageous embodiment of the cathode block according to the second aspect of the invention provides that the two connection regions between the bottom region and the side wall regions are configured curved inwards in relation to the cathode block viewed in longitudinal section as well as the two connecting regions between the edge regions and the side wall regions, based on the cathode block viewed in longitudinal section, are configured curved in an arc-shaped outward direction.
  • At least one arcuately curved section has a minimum radius of curvature of at least 2 cm, preferably of at least 10 cm and particularly preferably of at least 20 cm.
  • the second aspect of the present invention provides that at least one arcuate portion, with respect to the longitudinal section of the cathode block, oval segment, in particular circular arc, cosinus, in the form of a Gaussian distribution, elliptical segmental or in the shape of a Bezier curve is configured.
  • the cross-sectional plane extending in the longitudinal direction denotes the vertical plane running perpendicular to the width direction of the cathode block and parallel to the longitudinal direction of the cathode block.
  • angles between the one end and the other end of the at least one arcuately curved section of the at least one connecting region of the cathode block 95 to 175 ° is preferred 1 is 10 to 160 ° and more preferably 125 to 150 °.
  • the angle between the two ends of the curved portion denotes the larger of the two angles, the two fictitious, at the two ends of the section and starting, considered in the longitudinal section of the cathode block, each tangent to the curved portion extending straight lines.
  • At least one of the two edge regions and preferably both edge regions viewed in longitudinal section of the cathode block, in the longitudinal direction of the cathode block to the center of the Cathode block sloping sloping runs / run, with the inclination angle of the edge region or the edge regions relative to this level preferred is between 1 ° and 30 °, more preferably between 2 ° and 15 ° and most preferably between 3 ° and 10 °.
  • the bottom region extends at least in regions in a straight line, wherein the surface of the bottom region, with respect to the longitudinal direction an angle between -20 ° and 20 °, preferably between -10 ° and 10 ° and more preferably of 0 °.
  • a homogeneous distribution of the electric current density over the surface of the cathode block resulting from the use of the cathode block according to the invention in an electrolysis cell is achieved in particular if each of the two edge regions is more than 5 to 40%, preferably 10 to 35% and particularly preferably 15 to 30 % of the length of the cathode block extends and / or the bottom region extends over 10 to 90%, preferably 20 to 70% and particularly preferably 30 to 60% of the length of the cathode block.
  • the cathode block has a, seen in the longitudinal direction of the cathode block, varying material composition, wherein the material in the two edge regions preferably has a higher electrical resistivity has as the material in the bottom portion of the cathode block.
  • the cathode block contains 5 to 50% by weight and preferably between 10 to 30% by weight of acetylene coke in the two edge regions.
  • the Acetylenkoks does not change its electrical properties at the carried out during the production of the cathode block Graphit réelles intimid not or only slightly, so that the edge portions of the cathode block graphite with a lower degree of graphitization and thus with a greater electrical resistivity than in the case of graphitization without addition of the acetylene coke.
  • the cathode block in the bottom regions contain from 5 to 50% by weight and preferably between 10 to 40% by weight of titanium diboride, silica and / or chromium oxide.
  • the titanium diboride, silica or chromium oxide promotes in the process performed during the preparation of the cathode block
  • the second aspect of the present invention can be combined with the first aspect of the present invention, that is, according to a particularly preferred embodiment of the present invention, the cathode block has the in Related to the features described in the first aspect of the present invention as well as the features described in relation to the second aspect of the present invention.
  • Another object of the present invention is a cathode assembly, in particular for an aluminum electrolysis cell, which comprises at least two configured as described above cathode blocks.
  • the present invention relates to an electrolysis cell, in particular for the production of aluminum, which comprises a previously described cathode arrangement, a layer of liquid aluminum arranged on the top side of the cathode arrangement, a melt layer thereon and an anode above the melt layer.
  • an electrolysis cell in particular for the production of aluminum, which comprises a previously described cathode arrangement, a layer of liquid aluminum arranged on the top side of the cathode arrangement, a melt layer thereon and an anode above the melt layer.
  • FIG. 1 is a perspective sectional view of a cathode block according to the prior art
  • FIG. 2 is a perspective sectional view of a cathode block according to an embodiment of the first aspect of the present invention.
  • FIG. 3 shows a front view of the cathode block section shown in FIG. 2,
  • FIG. 4 is a cross-sectional view of a cathode block according to another embodiment of the first aspect of the present invention
  • 5 is an illustration of possible embodiments of the arcuate outwardly curved portion of a cathode block according to various embodiments of the first aspect of the invention
  • FIG. 6 is a longitudinal sectional view of a cathode block according to the prior art
  • FIG. 7 is a longitudinal sectional view of a cathode block according to an embodiment of the second aspect of the present invention.
  • FIG. 8 is a longitudinal sectional view of a cathode block according to another embodiment of the second aspect of the present invention.
  • 9a-e are schematic representations of the distribution of the electric current density at the surface of different cathode blocks when the respective cathode block is used in an electrolysis cell
  • FIG. 10 is a perspective view of the cathode block shown in FIG. 6 according to the prior art
  • FIG. 1 1 is a perspective view of a cathode block according to a
  • FIG. 12 is a perspective view of a cathode block according to another embodiment of the second aspect of the present invention and a perspective view of a cathode block according to another embodiment of the second aspect of the present invention.
  • Fig. 1 shows a perspective sectional view of a cathode block according to the prior art.
  • the cathode block has a groove 12a arranged on one side 10a of the cathode block and extending in the longitudinal direction y of the cathode block for receiving a bus bar.
  • the cathode block also has an opposite side 14a, which has the groove 12a, with a surface 16a which, when the cathode block is used in an electrolysis cell, faces the layer of liquid aluminum arranged above the cathode block.
  • the surface 16a is flat.
  • the numerals a are provided with the subscript a to distinguish these reference numerals from the corresponding reference numerals of the figures representing the present invention.
  • Fig. 2 is a perspective sectional view of a cathode block according to an embodiment of the first aspect of the invention.
  • the width Bi measured in the width direction x of the cathode block shown in FIG. 2 is about 42 cm and the width B 2 of the groove 12 is about 20 cm.
  • the length L of the cathode block measured in the longitudinal direction y may be, for example, 2.5 to 4.0 m.
  • the cathode block shown in FIG. 2 differs from that shown in FIG. 1 in that a portion of the surface 16 of the side 14 of the side opposite the side 10 having the at least one groove 12 Cathode block, seen in cross-section of the cathode block, is arcuately curved outward.
  • the sectional curve of the surface 16 resulting in the cross section of the cathode block is identified by reference numeral 18 in FIG.
  • This sectional curve 18 is arc-shaped over its entire width Bi measured in the width direction x and thus represents an arcuately curved section 20 of the cross-sectional surface 16.
  • the apex 22 of the arcuate outwardly curved section 20 relative to the in the cross section of the cathode block perpendicular to the at least one groove 12 having side 10 extending direction z is arranged vertically above the groove 12.
  • the region of the surface 16 arranged in the direction z above the groove 12 is identified by the reference numeral 24 in FIG.
  • the distribution of the electric current density in the use of the cathode block in an electrolytic cell compared to the cathode block shown in Fig. 1 is made uniform and thereby reduces a wave formation in the arranged above the cathode block layer of liquid aluminum.
  • FIG. 3 shows the cross section of the cathode block cutout shown in FIG. 2.
  • the quotient of the distance hi from the apex 22 of the curved section 20 to the lowest point of the groove 12 and the distance h 2 from the lowest point of the side 14 facing the groove 12 is equal to 14 the lowest point of the groove 12 in this embodiment is about 1.4: 1.
  • a cathode block according to a further embodiment of the first aspect of the invention is shown in cross-section.
  • the cathode block shown in FIG. 4 has two grooves 12, 12 'for receiving in each case one bus bar and the surface 16 of the cathode block has, seen in cross-section, two arcuately outwardly curved sections 20, 20', wherein the plate teltician 22, 22 'of each arcuate outwardly curved portion 20, 20' in the direction perpendicular to the grooves 12, 12 'having side 10 oriented direction z above the corresponding groove 12, 12' is arranged.
  • FIG. 5 shows an illustration of possible embodiments of the arcuate outwardly curved portion of a cathode block according to various embodiments of the first aspect of the invention. More precisely, FIG. 5 shows possible sectional curves 18a-e which can form an arcuately curved section of the cathode block surface in the cross section of the cathode block.
  • the x values range from (-0.5) times the cathode block width to 0.5 times the cathode block width and the y values indicate the height of the cathode surface relative to a fictitious middle horizontal.
  • the cut curve 18a has the shape of a semicircle
  • the cut curve 18b the shape of a parabolic section
  • the cut curve 18c the shape of a half ellipse
  • the cut curve 18d the shape of a cosine curve
  • the cut curve 18e the shape of a cosine curve in the fourth power , ie the function cos 4 (x).
  • FIG. 6 shows a section of a cathode block shown in longitudinal section according to the prior art.
  • the cathode block according to FIG. 6 has a trough-shaped surface 16a, which, viewed in a longitudinal section of the cathode block, faces in the use of the cathode block in an electrolysis cell the layer of liquid aluminum arranged above the cathode block and carried by the cathode block.
  • the trough comprises two edge regions 26a, of which only one is shown in the sectional illustration of FIG.
  • edge regions 26a and the bottom region 28a in each case pass over angled transitions into the sidewall regions 30a.
  • FIG. 7 shows a section of a cathode block shown in longitudinal section according to an embodiment of the second aspect of the present invention.
  • the cathode block shown in FIG. 7 differs from the cathode block shown in FIG. 6 in that, viewed in the longitudinal section of the cathode block, the connection region 32 between the edge region 26 and the sidewall region 30 is arcuately outwardly curved, which is arcuate curved section 34 has a length Li of more than 2 cm measured in the longitudinal direction y of the cathode block.
  • This curved transition between the edge region 26 and the sidewall region 30 avoids an electric current density valley in this region of the cathode block surface 16 when the cathode block is used in an electrolysis cell and thus reduces the formation of waves in the layer of liquid aluminum.
  • the quotient of the highest height h 3 in the edge region 26 and the lowest height h in is the bottom portion 28 of the cathode block about 2: 1.
  • the angle ⁇ between the one end and the other end of the arc-shaped curved portion 34 is about 120 °.
  • 8 shows a section of a cathode block shown in longitudinal section according to a further embodiment of the second aspect of the present invention.
  • connection region 32 between the edge region 26 and the side wall region 30 instead of the connection region 32 between the edge region 26 and the side wall region 30, the connection region 36 between the side wall region 30 and the Bottom portion 28 is designed as an arcuate inwardly curved portion 34, wherein the arcuate curved portion 34 has a measured in the longitudinal direction y of the cathode block length Li of more than 2 cm.
  • This curved transition between the sidewall region 30 and the bottom region 28 avoids a peak in the electric current density in this region of the cathode block surface 16 when the cathode block is used in an electrolysis cell and thus further reduces the formation of waves in the layer of liquid aluminum.
  • FIGS. 9a-e show a schematic representation of the distribution of the electric current density occurring on the surface of different cathode blocks when the respective cathode block is used in an electrolysis cell. overall In more detail, FIGS. 9a-e respectively show the distribution of the electrical current density, which is projected into the horizontal plane, on the surface of the respective cathode block during operation of the electrolysis cell.
  • the legend 38 shown in FIGS. 9a-e indicates which hatching in FIGS. 9a-e corresponds in each case to which electrical current density.
  • FIG. 9a shows the distribution of current density using a prior art trough-shaped cathode block as shown in FIGS. 6 and 10.
  • Fig. 9b the distribution of the electric current density using a cathode block as shown in Fig. 2 according to the first aspect of the present invention having an outwardly curved surface 16 (see Fig. 2) and otherwise the same configuration as the cathode block of Fig. 10.
  • the curvature of the cathode block surface especially in the central region viewed in the longitudinal direction y of the cathode block, results in a substantially more homogeneous distribution of the electric current density across the width (x direction) of the cathode block as in the cathode block shown in Fig. 9a.
  • Fig. 9c is shown the distribution of the electric current density using a cathode block as shown in Fig. 11, which is formed simultaneously according to the first aspect of the invention and also formed according to the second aspect of the invention.
  • the surface 16 of the cathode block according to the second aspect of the invention has a longitudinally-trough-shaped surface 16 (see FIG. 11), the trough having two edge regions 26, 26 'and one seen in the longitudinal direction y of the cathode block between the edge regions 26, 26 'arranged and based on the edge regions 26, 26' lowered bottom portion 28, wherein between the Edge regions 26, 26 'and the bottom region 28 is provided in each case a side wall region 30, 30' connecting the corresponding edge region 26, 26 'and the bottom region 28.
  • FIG. 11 has an outwardly directed curvature of the surface 16, viewed in cross-section of the cathode block, but not shown in FIG. 11 for the sake of simplicity.
  • the embodiment of the cathode block surface 16 shown in FIG. 11 leads to a further homogenization of the distribution of the electric current density, in particular in the region of the boxes 40 drawn in FIG. 9c.
  • Fig. 9d shows the distribution of the electric current density using a cathode block as shown in Fig. 12.
  • the cathode block shown in FIG. 12 substantially corresponds to the embodiment shown in FIG. 11, wherein in FIG. 12 the edge regions 26, 26 ', viewed in a longitudinal section of the cathode, are viewed at an angle ⁇ to the center of the horizontal Cathode block inclined towards.
  • the distribution of the electric current density in the region of the boxes 40, ie, at the longitudinal end of the cathode block is thereby additionally clearly homogenized.
  • Fig. 9e shows the distribution of the electric current density using a cathode block as shown in Fig. 13.
  • the cathode block shown in FIG. 13 The cathode block shown in FIG.
  • the cathode block shown in FIG. 13 essentially corresponds to the embodiment shown in FIG. 12, the cathode block shown in FIG. 13 having a locally varying material composition, specifically the cathode block sections 42, 42 arranged below the edge regions 26, 26 '', ie the areas hatched in simple hatched areas 42, 42' of the cathode block, acetylene coke are added and the arranged below the bottom portion 28, in Fig. 13 double hatched marked area 44 of the cathode block titanium diboride is added.
  • the distribution of the electric current density in the middle area of the cathode surface identified by the box 40 is once again additionally homogenized compared to the distribution shown in FIG. 9d by this measure.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)

Abstract

L'invention concerne un bloc cathodique pour une cellule électrolytique d'aluminium, en particulier à base de carbone et/ou de graphite, comprenant au moins une rainure située sur un des côtés du bloc cathodique et s'étendant dans la direction longitudinale de ce bloc pour recevoir une barre omnibus. Au moins un segment de la face supérieure du côté du bloc cathodique, opposé au côté comportant ladite rainure, vu en coupe transversale du bloc cathodique, est incurvé vers l'extérieur en forme d'arc. Le sommet du segment incurvé vers l'extérieur en forme d'arc est situé au-dessus de la rainure, par rapport à la direction perpendiculaire au côté comportant ladite rainure, vu en coupe transversale du bloc cathodique. En outre, l'invention concerne un bloc cathodique pour une cellule électrolytique d'aluminium, en particulier à base de carbone et/ou de graphite, présentant une face supérieure en forme de cuvette, vue en coupe longitudinale du bloc cathodique. La cuvette comprend deux zones de bordure et, vue en coupe longitudinale du bloc cathodique, une zone de fond située entre les zones de bordure et abaissée par rapport aux zones de bordure. Entre les deux zones de bordure et la zone de fond se trouve une zone de paroi latérale reliant la zone de bordure correspondante et la zone de fond. Au moins une des deux zones de liaison situées entre les zones de bordure et les zones de paroi latérale et/ou au moins une des deux zones de liaison situées entre la zone de fond et les zones de paroi latérale est/sont incurvées en forme d'arc, le segment incurvé en forme d'arc présentant une longueur supérieure à 2 cm.
PCT/EP2012/072046 2011-11-09 2012-11-07 Bloc cathodique à face supérieure bombée et/ou arrondie Ceased WO2013068412A2 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP2014540439A JP2014532816A (ja) 2011-11-09 2012-11-07 湾曲した表面および／または丸みのある表面を有するカソードブロック
EP12786943.6A EP2776608A2 (fr) 2011-11-09 2012-11-07 Bloc cathodique à face supérieure bombée et/ou arrondie
CA2854928A CA2854928A1 (fr) 2011-11-09 2012-11-07 Bloc cathodique a face superieure bombee et/ou arrondie
IN3395CHN2014 IN2014CN03395A (fr) 2011-11-09 2012-11-07
CN201280055341.8A CN103958740A (zh) 2011-11-09 2012-11-07 具有半球形和/或圆形表面的阴极块

Applications Claiming Priority (2)

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DE201110086044 DE102011086044A1 (de) 2011-11-09 2011-11-09 Kathodenblock mit gewölbter und/oder gerundeter Oberfläche
DE102011086044.4 2011-11-09

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WO2013068412A2 true WO2013068412A2 (fr) 2013-05-16
WO2013068412A3 WO2013068412A3 (fr) 2013-10-24

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DE (1) DE102011086044A1 (fr)
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CN115142098B (zh) * 2022-06-15 2023-06-30 赣州晨光稀土新材料有限公司 一种异型阴极以及应用其调节极距稳定的电解炉

Citations (1)

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WO2011148347A1 (fr) 2010-05-28 2011-12-01 Kan-Nak S.A. Conception de cathode de cellule hall-héroult

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US3067124A (en) * 1958-07-24 1962-12-04 Montedison Spa Furnace for fused-bath electrolysis, particularly for aluminum production from alo
NL129768C (fr) * 1965-01-06
CH567579A5 (en) * 1970-02-21 1975-10-15 Sigri Elektrographit Gmbh Carbon plate armour for graphite foil - for fusion electrolysis cells
DE69008410D1 (de) * 1989-02-20 1994-06-01 Comalco Alu Zelle zur schmelzflusselektrolytischen Gewinnung von Aluminium.
DE4118304A1 (de) * 1991-06-04 1992-12-24 Vaw Ver Aluminium Werke Ag Elektrolysezelle zur aluminiumgewinnung
US5362366A (en) * 1992-04-27 1994-11-08 Moltech Invent S.A. Anode-cathode arrangement for aluminum production cells
AU688098B2 (en) * 1994-09-08 1998-03-05 Moltech Invent S.A. Aluminium electrowinning cell with improved carbon cathode blocks
DE69809202T2 (de) * 1997-05-23 2003-05-28 Moltech Invent S.A., Luxemburg/Luxembourg Aluminium-herstellungszelle und kathode
WO1999002763A1 (fr) * 1997-07-08 1999-01-21 Moltech Invent S.A. Conception relative a une cellule d'electrolyse pour la production d'aluminium
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CN101451250A (zh) * 2008-10-24 2009-06-10 中南大学 一种减少铝电解槽水平电流的曲面型阴极结构
CN101724859B (zh) * 2009-12-15 2011-05-18 中南大学 一种异形结构阴极铝电解槽焙烧方法

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EP2776608A2 (fr) 2014-09-17
WO2013068412A3 (fr) 2013-10-24
IN2014CN03395A (fr) 2015-07-03
CA2854928A1 (fr) 2013-05-16
CN103958740A (zh) 2014-07-30
DE102011086044A1 (de) 2013-05-16
JP2014532816A (ja) 2014-12-08

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