US3661736A - Refractory hard metal composite cathode aluminum reduction cell - Google Patents

Refractory hard metal composite cathode aluminum reduction cell Download PDF

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US3661736A
US3661736A US822395A US3661736DA US3661736A US 3661736 A US3661736 A US 3661736A US 822395 A US822395 A US 822395A US 3661736D A US3661736D A US 3661736DA US 3661736 A US3661736 A US 3661736A
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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
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes

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  • cathodes made of fused refractory hard metal composited with certain bonding agents can be used to replace the conventional carbon lining of an aluminum reduction cell.
  • Such composite cathodes combine the advantages of conventional carbon linings (structural integrity and relative cheapness) with specific basic property improvements conferred by the presence of a refractory hard metal phase. These improvements are l) wettability by molten aluminum, (2)
  • composition control is met in the present invention by employing refractory hard metals, preferably TiB -TiC alloys, which have been purified by arc melting under controlled conditions, as described in my copending application, Ser. No. 822,705, filed May 7, 1969.
  • the amount of TiC in the alloy may vary over a wide range, for example, from to 50 percent by weight.
  • the cathodes of the present invention make possible an enormous improvement in the performance of reduction cells. Specifically, a 50 percent reduction in anode-cathode distance is feasible when the molten aluminum pool which now functions as cathode is replaced by a solid, wettable cathode block. Such a reduction in anode-to-cathode distance proportionately reduces the interelectrode voltage drop. The voltage savings may be utilized to obtain an increase of approximately 40 percent in current density, with an equivalent increase in output of metal from the cell.
  • Refractory hard metals and alloys prepared in this way may be used as structural members, if desired, but the particular purpose of the present invention is to reveal their application in the form of composite bodies. For this purpose it is no longer necessary to consider large, self-bonded structural shapes of high mechanical integrity. Instead, fractured lumps, pieces and even small particles of refractory hard metal alloys may be employed.
  • the refractory hard metals may be composited with bonding agents, such as graphite with pitch or other carbonaceous binders. For such use, adherence to strict specifications for mechanical strength and impact strength is no longer necessary since mechanical support is provided by the carbon, or other electrically conducting matrix.
  • the process of fabricating the composite bodies may be similar to that for manufacture of carbon anodes, both in technique and in costs.
  • particulate refractory hard material ranging from pass 100 mesh to above 4 mesh on the Tyler screen system may be prepared by casting, for example, an alloy of TiB with 40 percent TiC in arc fumaces of known construction equipped to directly produce the desired range of particle sizes by suitably dispersing and chilling the melt.
  • the resulting particulate grog may then be blended with graphite powder of the same general particle size distribution range in conventional mixing apparatus.
  • the proportion of carbon or graphite to refractory hard metal grog can vary widely, over the range 2 to 50 volume percent refractory hard metal.
  • the proportion of exposed RHM surface area in the resulting carbon-bonded composite equals the volume percentage of the refractory hard metal component.
  • the proportion of RHM to carbon should be the minimum needed to impart the desired electrochemical properties to the composite.
  • the resulting blend can be cold pressed into green bodies.
  • These bodies may then be sintered using, for example, conditions similar to those adopted in preparing anode carbon blocks for the Hall process. In essence, the conditions provide for a gradual increase of temperature over an extended time period until a maximum near l,100 C is reached. This brake is followed by a slow cool.
  • the method of fabricating composites of this type is, of course, not restricted to a blending-sintering type operation.
  • Hot-pressing of an arc melted refractory hard metal alloy-carbon mixture may be employed.
  • an alloy of refractory hard metal with carbon can be produced directly in the arc furnace.
  • hot isostatic compaction can be used in apparatus conventional for this process.
  • the resulting carbonRHM composites show a particularly desirable combination of properties.
  • the refractory hard metal component functions as an equipotential surface on which deposition of aluminum ions occurs preferentially, i.e., the refractory hard metal forms the electrochemically active I part of the composite system.
  • the carbon matrix provides mechanical support for the wettable RHM surface, and in addition, permits electricity to be conducted from the RHM dominated surface to current collector bars such as are now used with conventional carbon linings.
  • the carbon fraction of the surface of the composite electrode becomes protected by an aluminum carbide layer.
  • the high overvoltage for aluminum and sodium deposition and the inherent high electrical resistivity of the aluminum carbide cooperate to make it immune from further deterioration by aluminum or sodium once a protective layer forms.
  • This'aluminum carbide layer functions somewhat like the corrosion resisting oxide films on stainless alloys.
  • FIG. 1 is a schematic view showing the refractory hard metal-carbon-composite.
  • FIG. 2 is a view of another embodiment of the invention showing large chunks of refractory hard metal.
  • FIG. 3 is a perspective view of another embodiment of the invention and FIG. 3A is a typical section through FIG. 3.
  • FIG. 4 is a view of another embodiment of the invention.
  • FIG. 5 is a sectional view of an electrolyte cell according to the present invention.
  • RHM fused-cast purified alloy particulate grog having'an electrochemically active surface is shown at 10.
  • the surface layer 11, believed to be of Al C makes this region electrochemically inert and stable with respect to aluminumcryolite.
  • the supporting and conducting carbon matrix is shown at 12.
  • RHM grog It is not necessary that composites be formed using only particles of RHM grog.
  • large chunks of RHM alloy 20, ranging from one-fourth inch to several inches average diameter, may be embedded in a supporting carbon matrix.
  • large chunks 30 of REM alloy are cast to develop at least one reasonably flat side, and set in a conducting matrix to form a flagstone type surface.
  • the surface layer 31 is shown in FIG.
  • the supporting matrix be restricted to carbon and graphite.
  • aluminum carbide may be used as a filler material. This is particularly suitable when relatively large chunks of REM alloy are used in the flagstone type cathode.
  • pure Al,C old reacted reduction cell linings, or Al C NaFAlF mixture may be used.
  • a cathode of this type will consist basically of three components: (I) relatively large chunks of arc-melted RHM alloy 40, (2) a powdered filler 41 such as ALC or similar material between the refractory hard metal chunks and, (3) a lower conductive layer 42, preferably carbon or graphite, forming a substrate layer providing electrical contact between the RHM surface and current collector bars of the cell.
  • a powdered filler 41 such as ALC or similar material between the refractory hard metal chunks and, (3) a lower conductive layer 42, preferably carbon or graphite, forming a substrate layer providing electrical contact between the RHM surface and current collector bars of the cell.
  • a three-component composite of this type would be fabricated, for example, by cold-pressing followed by sintering, conditions being chosen to promote formation of a solid bond between aluminum carbide particles and between aluminum carbide and carbon. 7
  • Such a fusion process yields a mixed valency semi-conductor with a much higher electrical conductivity than aluminum carbide.
  • a third component such as carbon is superfluous, and may be dispensed with.
  • blocks may be fabricated in sizes of conventional bricks. Bonding of such bricks can be accomplished by means of conventional carbon pastes like those now used in reduction cells.
  • a part of this invention is a reduction cell designed particularlysuitable for using the composite cathodes of the type hereinbefore described.
  • such a reduction furnace shown generally at 50 may comprise one or more carbon anodes such as 51 and roof or enclosure 53.
  • a cell gas space 54 is found above the electrolyte 55.
  • the RHM composite dry cathodes 56 are placed below the lower surface 51A of the anodes.
  • the sloped electrode surfaces 56A permit run-off of aluminum into accumulating chamber 57 and directional flow of anode gas to gas space 54.
  • the carbon supporting matrix for the RHM composite is shown at 58.
  • the steel cathode current collector bars 59 are embedded into insulation 52 and supporting matrix 58.
  • the composite cathodes may be used in cells where the molten aluminum is drained from the sloping surface 56A as it is deposited, and accumulated in collection chamber 57 within the cell.
  • the required slope of the wettable refractory hard metal surface is not large; a gradient of 1 to 10 is normally all that is needed to secure adequate removal of molten aluminum as it deposits. Obviously, however, a steeper slope can be used, such as the one shown in FIG. 5.
  • Such a design has the advantage of using an anode system identical to that presently used in present commercially operated prebake cells.
  • composite cathode materials of this invention are not limited to installations in a near horizontal position.
  • composite cathodes may be appropriately shaped for use in a vertical arrangement, either in cells using conventional cryolitic electrolytes, or in cells for electrolytic reduction of aluminum chloride.
  • a process for producing aluminum comprising providing.
  • an electrolyte in a cell with aluminum dissolved therein providing at least one anode in said cell, providing at least one cathode in said cell, said cathode comprising refractory hard metal imbedded in an electrically conductive matrix said matrix selected from the group consisting of aluminum carbide and an arc melted material comprising aluminum carbide and titanium carbide wherein the particles of said hard metal are relatively larger than the particles of said matrix, passing electrical current between said anode and said cathode causing said alumina to react yielding aluminum ions, said aluminum ions depositing directly on said cathode.
  • a process according to claim 1 wherein said refractory hard meta] comprises an arc melted material comprising titanium boride and titanium carbide.
  • said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.
  • Apparatus for producing aluminum comprising means for confining a molten electrolyte containing alumina, at least one anode contacting said electrolyte, at least one cathode contacting said electrolyte, said cathode comprising a composite of refractory hard metal imbedded in an electrically conductive matrix said matrix selected from the group consisting of aluminum carbide and an arc melted material comprising aluminum carbide and titanium carbide wherein the particles of said hard material are relatively larger than the particles of said matrix, means for causing electrical current flow between said anode and said cathode whereby aluminum ions are deposited on said cathode.
  • Apparatus according to claim 8 in which means are provided for continually removing and collecting metallic aluminum from said cathode.
  • Apparatus according to claim 9 in which the means for removing aluminum from said cathode is means which support said cathode on an incline.
  • said refractory hard metal comprises an arc melted material comprising titanium boride and titanium carbide.
  • said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.

Abstract

The present invention is directed to cathodes of fused refractory hard metal alloy composited with certain bonding agents and their use, replacing the conventional carbon lining of an aluminum reduction cell.

Description

United States Patent Holliday May 9, 1972 [54] REFRACTORY HARD lVIETAL References Cited COMPOSITE CATHODE ALUMINUM UNITED STATES PATENTS REDUCTION CELL 3,400,061 9/1968 Lewis et a] ..204/67 [72] Inventor: Robin D. Holliday, New South Wales, 3,442,787 1969 Landfum 61 R X Australia 3,502,553 3/1970 Gruber ..204/243 R X 3,514,520 5/1970 Bacchiega et al. ..204/243 R X [73] Assigneez Olin Mathieson Chemical Corporation Primary Examiner-John H. Mack [22] led. May 1969 Assistant ExaminerD. R. Valentine [21] App]. No.: 822,395 Attorney-Richard S. Strickler, Robert H. Bachman, Donald R. Motsko and Thomas P. ODay [52] U.S. Cl. I ..204/67, 204/243 R, 204/291 [57] ABSTRACT [51] Int. Cl ....C22d 3/12, C22d 3/02, B0lk 3/06 [58] Field of Search ..206/67, 243-247, The Premt invention is directed cathodes of fused refrac- 206/291 tory hard metal alloy composited with certain bonding agents and their use, replacing the conventional carbon lining of an aluminum reduction cell.
15 Claims, 6 Drawing Figures PATENTEDMAY 9 I972 3661.736
sum 1 0F 2 ROB/N I 0. HULL/DAY f BY 1%) 924 ATTORNEY INVENTOR.
PATENTEHMAY 91912 3,661,736
sum 2 OF 2 FIG-4 NVENTOR'.
ROB/N l2 HOLL /DAY 5 BY kj/ ZMMM ATTORNEY REFRACTORY HARD METAL COMPOSITE CATHODE ALUMINUM REDUCTION CELL Application of refractory hard metals such as TiB -TiC alloys in aluminum reduction cells has been previously considered to require structural members such as rods, bars, etc. Successful use of such members requires bodies having high-strength and high density. Such bodies have been previously considered to be fabricable only by hot-pressing.
It has proved extremely difficult to achieve the necessary high level of mechanical properties in conjunction with the stringent control of chemical composition essential for avoiding specific severe forms of corrosion.
Such materials have previously been considered for use in reduction cells, but only in the form of self-bonded, hotpressed shapes. Application has been restricted because of the difficulty and expense involved in fabricating such shapes to meet the necessary stringent mechanical and composition requirements. See French Pat. No. 1,311,473.
According to the present invention it has been found that cathodes made of fused refractory hard metal composited with certain bonding agents can be used to replace the conventional carbon lining of an aluminum reduction cell.
Such composite cathodes combine the advantages of conventional carbon linings (structural integrity and relative cheapness) with specific basic property improvements conferred by the presence of a refractory hard metal phase. These improvements are l) wettability by molten aluminum, (2)
low overvoltage for aluminum deposition from cryolite, (3)
extremely low solubility in molten aluminum-cryolite systems, (4) freedom from penetration by aluminum-cryolite, when prepared in such a way as to minimize deleterious impurity effects and (5) good electrical conductivity.
The requirements of composition control are met in the present invention by employing refractory hard metals, preferably TiB -TiC alloys, which have been purified by arc melting under controlled conditions, as described in my copending application, Ser. No. 822,705, filed May 7, 1969. The amount of TiC in the alloy may vary over a wide range, for example, from to 50 percent by weight.
This combination of properties makes it possible to use such composites as solid monolithic cathodes on which Al ions may be deposited directly. If the aluminum is allowed to run off as it deposits and is collected in a suitable receptacle in the cell, then many disadvantages of the Hall cell system are by-passed.
The cathodes of the present invention make possible an enormous improvement in the performance of reduction cells. Specifically, a 50 percent reduction in anode-cathode distance is feasible when the molten aluminum pool which now functions as cathode is replaced by a solid, wettable cathode block. Such a reduction in anode-to-cathode distance proportionately reduces the interelectrode voltage drop. The voltage savings may be utilized to obtain an increase of approximately 40 percent in current density, with an equivalent increase in output of metal from the cell.
Refractory hard metals and alloys prepared in this way may be used as structural members, if desired, but the particular purpose of the present invention is to reveal their application in the form of composite bodies. For this purpose it is no longer necessary to consider large, self-bonded structural shapes of high mechanical integrity. Instead, fractured lumps, pieces and even small particles of refractory hard metal alloys may be employed. The refractory hard metals may be composited with bonding agents, such as graphite with pitch or other carbonaceous binders. For such use, adherence to strict specifications for mechanical strength and impact strength is no longer necessary since mechanical support is provided by the carbon, or other electrically conducting matrix. The process of fabricating the composite bodies may be similar to that for manufacture of carbon anodes, both in technique and in costs.
Thus, particulate refractory hard material ranging from pass 100 mesh to above 4 mesh on the Tyler screen system may be prepared by casting, for example, an alloy of TiB with 40 percent TiC in arc fumaces of known construction equipped to directly produce the desired range of particle sizes by suitably dispersing and chilling the melt.
The resulting particulate grog may then be blended with graphite powder of the same general particle size distribution range in conventional mixing apparatus.
The proportion of carbon or graphite to refractory hard metal grog can vary widely, over the range 2 to 50 volume percent refractory hard metal. When the size of the RHM particles and the graphite or carbon particles is essentially the same, it can be'shown that the percentage of exposed RHM surface area in the resulting carbon-bonded composite equals the volume percentage of the refractory hard metal component. To minimize material costs, the proportion of RHM to carbon should be the minimum needed to impart the desired electrochemical properties to the composite.
After addition and blending of pitch or other form of binder is carried out, the resulting blend can be cold pressed into green bodies. These bodies may then be sintered using, for example, conditions similar to those adopted in preparing anode carbon blocks for the Hall process. In essence, the conditions provide for a gradual increase of temperature over an extended time period until a maximum near l,100 C is reached. This brake is followed by a slow cool.
The method of fabricating composites of this type is, of course, not restricted to a blending-sintering type operation. Hot-pressing of an arc melted refractory hard metal alloy-carbon mixture may be employed. Altemately, an alloy of refractory hard metal with carbon can be produced directly in the arc furnace. Further, hot isostatic compaction can be used in apparatus conventional for this process.
The resulting carbonRHM composites show a particularly desirable combination of properties. The refractory hard metal component functions as an equipotential surface on which deposition of aluminum ions occurs preferentially, i.e., the refractory hard metal forms the electrochemically active I part of the composite system. The carbon matrix provides mechanical support for the wettable RHM surface, and in addition, permits electricity to be conducted from the RHM dominated surface to current collector bars such as are now used with conventional carbon linings.
It is postulated that the carbon fraction of the surface of the composite electrode becomes protected by an aluminum carbide layer. The high overvoltage for aluminum and sodium deposition and the inherent high electrical resistivity of the aluminum carbide cooperate to make it immune from further deterioration by aluminum or sodium once a protective layer forms. This'aluminum carbide layer functions somewhat like the corrosion resisting oxide films on stainless alloys.
The invention will be better understood from referring to the drawings.
FIG. 1 is a schematic view showing the refractory hard metal-carbon-composite.
FIG. 2 is a view of another embodiment of the invention showing large chunks of refractory hard metal.
FIG. 3 is a perspective view of another embodiment of the invention and FIG. 3A is a typical section through FIG. 3.
FIG. 4 is a view of another embodiment of the invention.
FIG. 5 is a sectional view of an electrolyte cell according to the present invention.
The system of the present invention is depicted in HO. 1. RHM fused-cast purified alloy particulate grog, having'an electrochemically active surface is shown at 10. The surface layer 11, believed to be of Al C makes this region electrochemically inert and stable with respect to aluminumcryolite. The supporting and conducting carbon matrix is shown at 12.
It is not necessary that composites be formed using only particles of RHM grog. In another embodiment of the invention shown in FIG. 2, large chunks of RHM alloy 20, ranging from one-fourth inch to several inches average diameter, may be embedded in a supporting carbon matrix.
In another type of composite shown in FIG. 3 and 3A, large chunks 30 of REM alloy are cast to develop at least one reasonably flat side, and set in a conducting matrix to form a flagstone type surface. The surface layer 31 is shown in FIG.
It is not necessary that choice for the supporting matrix be restricted to carbon and graphite. lndeed, aluminum carbide may be used as a filler material. This is particularly suitable when relatively large chunks of REM alloy are used in the flagstone type cathode. Moreover, either pure Al,C old reacted reduction cell linings, or Al C NaFAlF mixture may be used.
Preferably, as shown in FIG. 4, a cathode of this type will consist basically of three components: (I) relatively large chunks of arc-melted RHM alloy 40, (2) a powdered filler 41 such as ALC or similar material between the refractory hard metal chunks and, (3) a lower conductive layer 42, preferably carbon or graphite, forming a substrate layer providing electrical contact between the RHM surface and current collector bars of the cell.
A three-component composite of this type would be fabricated, for example, by cold-pressing followed by sintering, conditions being chosen to promote formation of a solid bond between aluminum carbide particles and between aluminum carbide and carbon. 7
It is also possible to achieve a satisfactory filler for a composite cathode by using aluminum carbide alloyed with materials such as TiC by arc welding.
Such a fusion process yields a mixed valency semi-conductor with a much higher electrical conductivity than aluminum carbide. ll: this case, use of a third component such as carbon is superfluous, and may be dispensed with.
In addition to carbon and aluminum carbide, other materials of the refractory hard metal class such as TiC and TiN or their alloys are also suitable for bonding the electrochemically active solid fused chunks of RHM alloy.
Clearly, there is no restriction on the size of composite shapes other than that imposed by size limits of apparatus needed for fabrication. For example, blocks may be fabricated in sizes of conventional bricks. Bonding of such bricks can be accomplished by means of conventional carbon pastes like those now used in reduction cells.
Also, a part of this invention is a reduction cell designed particularlysuitable for using the composite cathodes of the type hereinbefore described.
As shown in FlG. such a reduction furnace shown generally at 50 may comprise one or more carbon anodes such as 51 and roof or enclosure 53. A cell gas space 54 is found above the electrolyte 55. The RHM composite dry cathodes 56 are placed below the lower surface 51A of the anodes.
The sloped electrode surfaces 56A permit run-off of aluminum into accumulating chamber 57 and directional flow of anode gas to gas space 54.
The carbon supporting matrix for the RHM composite is shown at 58. The steel cathode current collector bars 59 are embedded into insulation 52 and supporting matrix 58.
As shown in FIG. 5, the composite cathodes may be used in cells where the molten aluminum is drained from the sloping surface 56A as it is deposited, and accumulated in collection chamber 57 within the cell. The required slope of the wettable refractory hard metal surface is not large; a gradient of 1 to 10 is normally all that is needed to secure adequate removal of molten aluminum as it deposits. Obviously, however, a steeper slope can be used, such as the one shown in FIG. 5.
Such a design has the advantage of using an anode system identical to that presently used in present commercially operated prebake cells.
The composite cathode materials of this invention are not limited to installations in a near horizontal position. In one embodiment of the invention, composite cathodes may be appropriately shaped for use in a vertical arrangement, either in cells using conventional cryolitic electrolytes, or in cells for electrolytic reduction of aluminum chloride.
This invention may be embodied in other forms or carried l. A process for producing aluminum comprising providing.
an electrolyte in a cell with aluminum dissolved therein, providing at least one anode in said cell, providing at least one cathode in said cell, said cathode comprising refractory hard metal imbedded in an electrically conductive matrix said matrix selected from the group consisting of aluminum carbide and an arc melted material comprising aluminum carbide and titanium carbide wherein the particles of said hard metal are relatively larger than the particles of said matrix, passing electrical current between said anode and said cathode causing said alumina to react yielding aluminum ions, said aluminum ions depositing directly on said cathode.
2. A process according to claim 1 in which metallic aluminum runs off said cathode and is collected at a point other than at said cathode.
3. A process according to claim 2 in which said aluminum flows by gravity from said cathode to a separate collection receptacle within said cell.
4. A process according to claim 1 wherein said refractory hard meta] comprises an arc melted material comprising titanium boride and titanium carbide.
5. A process according to claim 1 wherein said matrix comprises aluminum carbide. v
6. A process according to claim 1 wherein said refractory hard metal is at least 0.25 inch average diameter.
7. A process according to claim 1 wherein said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.
8. Apparatus for producing aluminum comprising means for confining a molten electrolyte containing alumina, at least one anode contacting said electrolyte, at least one cathode contacting said electrolyte, said cathode comprising a composite of refractory hard metal imbedded in an electrically conductive matrix said matrix selected from the group consisting of aluminum carbide and an arc melted material comprising aluminum carbide and titanium carbide wherein the particles of said hard material are relatively larger than the particles of said matrix, means for causing electrical current flow between said anode and said cathode whereby aluminum ions are deposited on said cathode.
9. Apparatus according to claim 8 in which means are provided for continually removing and collecting metallic aluminum from said cathode.
10. Apparatus according to claim 9 in which the means for removing aluminum from said cathode is means which support said cathode on an incline.
11. Apparatus according to claim 8 in which said means for collecting is a chamber within said cell. i
12. An apparatus according to claim 8 wherein said refractory hard metal comprises an arc melted material comprising titanium boride and titanium carbide.
13. An apparatus according to claim 8 wherein said matrix comprises aluminum carbide.
14. An apparatus according to claim 8 wherein said refractory hard metal is at least 0.25 inch average diameter.
15. An apparatus according to claim 8 wherein said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.

Claims (14)

  1. 2. A process according to claim 1 in which metallic aluminum runs off said cathode and is collected at a point other than at said cathode.
  2. 3. A process according to claim 2 in which said aluminum flows by gravity from said cathode to a separate collection receptacle within said cell.
  3. 4. A process according to claim 1 wherein said refractory hard metal comprises an arc melted material comprising titanium boride and titanium carbide.
  4. 5. A process according to claim 1 wherein said matrix comprises aluminum carbide.
  5. 6. A process according to claim 1 wherein said refractory hard metal is at least 0.25 inch average diameter.
  6. 7. A process according to claim 1 wherein said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.
  7. 8. Apparatus for producing aluminum comprising means for confining a molten electrolyte containing alumina, at least one anode contacting said electrolyte, at least one cathode contacting said electrolyte, said cathode comprising a composite of refractory hard metal imbedded in an electrically conductive matrix said matrix selected from the group consisting of aluminum carbide and an arc melted material comprising aluminum carbide and titanium carbide wherein the particles of said hard material are relatively larger than the particles of said matrix, means for causing electrical cUrrent flow between said anode and said cathode whereby aluminum ions are deposited on said cathode.
  8. 9. Apparatus according to claim 8 in which means are provided for continually removing and collecting metallic aluminum from said cathode.
  9. 10. Apparatus according to claim 9 in which the means for removing aluminum from said cathode is means which support said cathode on an incline.
  10. 11. Apparatus according to claim 8 in which said means for collecting is a chamber within said cell.
  11. 12. An apparatus according to claim 8 wherein said refractory hard metal comprises an arc melted material comprising titanium boride and titanium carbide.
  12. 13. An apparatus according to claim 8 wherein said matrix comprises aluminum carbide.
  13. 14. An apparatus according to claim 8 wherein said refractory hard metal is at least 0.25 inch average diameter.
  14. 15. An apparatus according to claim 8 wherein said matrix comprises an arc melted material comprising aluminum carbide and titanium carbide.
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Cited By (39)

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US4093524A (en) * 1976-12-10 1978-06-06 Kaiser Aluminum & Chemical Corporation Bonding of refractory hard metal
US4098651A (en) * 1973-12-20 1978-07-04 Swiss Aluminium Ltd. Continuous measurement of electrolyte parameters in a cell for the electrolysis of a molten charge
US4111765A (en) * 1976-12-23 1978-09-05 Diamond Shamrock Technologies S.A. Silicon carbide-valve metal borides-carbon electrodes
FR2455094A1 (en) * 1979-04-27 1980-11-21 Ppg Industries Inc CATHODE CURRENT CONDUCTING ELEMENT FOR ALUMINUM REDUCTION CELLS
EP0021850A1 (en) * 1979-07-02 1981-01-07 United States Borax & Chemical Corporation Alumina reduction cell, methods of producing such a cell, and use thereof in the manufacture of aluminium
FR2471425A1 (en) * 1979-12-05 1981-06-19 Alusuisse CATHODIC DEVICE FOR IGNATED ELECTROLYSIS OVEN, ESPECIALLY FOR THE PRODUCTION OF ALUMINUM
EP0033630A1 (en) * 1980-01-28 1981-08-12 Diamond Shamrock Corporation Electrolytic cell for electrowinning aluminium from fused salts
FR2482629A1 (en) * 1980-05-14 1981-11-20 Alusuisse ARRANGEMENT OF ELECTRODES OF A FUSION BATH ELECTROLYSIS CELL FOR MANUFACTURING ALUMINUM
US4308114A (en) * 1980-07-21 1981-12-29 Aluminum Company Of America Electrolytic production of aluminum using a composite cathode
US4333813A (en) * 1980-03-03 1982-06-08 Reynolds Metals Company Cathodes for alumina reduction cells
FR2500488A1 (en) * 1981-02-24 1982-08-27 Pechiney Aluminium Electrolytic prodn. of aluminium - in high current density cell with titanium di:boride particle cathode bed
WO1983000171A1 (en) * 1981-07-01 1983-01-20 De Nora, Vittorio Electrolytic production of aluminum
US4396482A (en) * 1980-07-21 1983-08-02 Aluminum Company Of America Composite cathode
WO1984000565A1 (en) * 1982-07-22 1984-02-16 Martin Marietta Corp Aluminum cathode coating cure cycle
WO1984000566A1 (en) * 1982-07-22 1984-02-16 Martin Marietta Corp Improved cell for electrolytic production of aluminum
EP0102186A2 (en) * 1982-07-22 1984-03-07 Commonwealth Aluminum Corporation Improved cell for electrolytic production of aluminum
EP0109358A1 (en) * 1982-11-15 1984-05-23 Schweizerische Aluminium Ag Cathode for a molten bath electrolytic cell
WO1984002723A1 (en) * 1982-12-30 1984-07-19 Eltech Systems Corp Aluminum production cell components
US4462886A (en) * 1981-10-23 1984-07-31 Swiss Aluminium Ltd. Cathode for a fused salt electrolytic cell
US4466995A (en) * 1982-07-22 1984-08-21 Martin Marietta Corporation Control of ledge formation in aluminum cell operation
US4466996A (en) * 1982-07-22 1984-08-21 Martin Marietta Corporation Aluminum cell cathode coating method
US4481052A (en) * 1983-01-28 1984-11-06 Martin Marietta Corporation Method of making refractory hard metal containing tiles for aluminum cell cathodes
US4492670A (en) * 1983-02-10 1985-01-08 Swiss Aluminium Ltd. Process for manufacturing solid cathodes
US4526911A (en) * 1982-07-22 1985-07-02 Martin Marietta Aluminum Inc. Aluminum cell cathode coating composition
US4544469A (en) * 1982-07-22 1985-10-01 Commonwealth Aluminum Corporation Aluminum cell having aluminum wettable cathode surface
US4582553A (en) * 1984-02-03 1986-04-15 Commonwealth Aluminum Corporation Process for manufacture of refractory hard metal containing plates for aluminum cell cathodes
US4624766A (en) * 1982-07-22 1986-11-25 Commonwealth Aluminum Corporation Aluminum wettable cathode material for use in aluminum reduction cell
EP0375148A2 (en) * 1988-11-17 1990-06-27 Praxair S.T. Technology, Inc. Production of molded refractory shapes
US5045269A (en) * 1988-11-17 1991-09-03 Union Carbide Coatings Service Technology Corporation Method for sintered shapes with controlled grain size
US5310476A (en) * 1992-04-01 1994-05-10 Moltech Invent S.A. Application of refractory protective coatings, particularly on the surface of electrolytic cell components
US5651874A (en) * 1993-05-28 1997-07-29 Moltech Invent S.A. Method for production of aluminum utilizing protected carbon-containing components
US5683559A (en) * 1994-09-08 1997-11-04 Moltech Invent S.A. Cell for aluminium electrowinning employing a cathode cell bottom made of carbon blocks which have parallel channels therein
US5753163A (en) * 1995-08-28 1998-05-19 Moltech. Invent S.A. Production of bodies of refractory borides
US6001236A (en) * 1992-04-01 1999-12-14 Moltech Invent S.A. Application of refractory borides to protect carbon-containing components of aluminium production cells
US6649040B1 (en) 1998-11-17 2003-11-18 Alcan International Limited Wettable and erosion/oxidation-resistant carbon-composite materials
CN102822392A (en) * 2010-03-30 2012-12-12 日本电极株式会社 Cathode carbon block for aluminum smelting purposes, and process for production thereof
CN105603462A (en) * 2016-02-25 2016-05-25 周俊和 Process for producing alloy aluminum in electrolytic tank based on electrolytic method
CN105734348A (en) * 2016-02-25 2016-07-06 周俊和 Process for producing alloy aluminum in aluminum electrolysis cell by adopting mix-melting method
CN105821450A (en) * 2016-02-25 2016-08-03 周俊和 Technology for producing alloy aluminum in electrolytic tank based on electrolytic method and aluminum reduction method

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US4111765A (en) * 1976-12-23 1978-09-05 Diamond Shamrock Technologies S.A. Silicon carbide-valve metal borides-carbon electrodes
FR2455094A1 (en) * 1979-04-27 1980-11-21 Ppg Industries Inc CATHODE CURRENT CONDUCTING ELEMENT FOR ALUMINUM REDUCTION CELLS
EP0021850A1 (en) * 1979-07-02 1981-01-07 United States Borax & Chemical Corporation Alumina reduction cell, methods of producing such a cell, and use thereof in the manufacture of aluminium
FR2471425A1 (en) * 1979-12-05 1981-06-19 Alusuisse CATHODIC DEVICE FOR IGNATED ELECTROLYSIS OVEN, ESPECIALLY FOR THE PRODUCTION OF ALUMINUM
EP0033630A1 (en) * 1980-01-28 1981-08-12 Diamond Shamrock Corporation Electrolytic cell for electrowinning aluminium from fused salts
US4333813A (en) * 1980-03-03 1982-06-08 Reynolds Metals Company Cathodes for alumina reduction cells
FR2482629A1 (en) * 1980-05-14 1981-11-20 Alusuisse ARRANGEMENT OF ELECTRODES OF A FUSION BATH ELECTROLYSIS CELL FOR MANUFACTURING ALUMINUM
US4308114A (en) * 1980-07-21 1981-12-29 Aluminum Company Of America Electrolytic production of aluminum using a composite cathode
US4396482A (en) * 1980-07-21 1983-08-02 Aluminum Company Of America Composite cathode
FR2500488A1 (en) * 1981-02-24 1982-08-27 Pechiney Aluminium Electrolytic prodn. of aluminium - in high current density cell with titanium di:boride particle cathode bed
WO1983000171A1 (en) * 1981-07-01 1983-01-20 De Nora, Vittorio Electrolytic production of aluminum
EP0072043A1 (en) * 1981-07-01 1983-02-16 Eltech Systems Corporation Electrolytic production of aluminum
US4650552A (en) * 1981-07-01 1987-03-17 Eltech Systems Corporation Electrolytic production of aluminum
US4462886A (en) * 1981-10-23 1984-07-31 Swiss Aluminium Ltd. Cathode for a fused salt electrolytic cell
WO1984000565A1 (en) * 1982-07-22 1984-02-16 Martin Marietta Corp Aluminum cathode coating cure cycle
EP0102186A2 (en) * 1982-07-22 1984-03-07 Commonwealth Aluminum Corporation Improved cell for electrolytic production of aluminum
US4466995A (en) * 1982-07-22 1984-08-21 Martin Marietta Corporation Control of ledge formation in aluminum cell operation
US4466996A (en) * 1982-07-22 1984-08-21 Martin Marietta Corporation Aluminum cell cathode coating method
EP0102186A3 (en) * 1982-07-22 1984-08-22 Martin Marietta Corporation Improved cell for electrolytic production of aluminum
WO1984000566A1 (en) * 1982-07-22 1984-02-16 Martin Marietta Corp Improved cell for electrolytic production of aluminum
US4624766A (en) * 1982-07-22 1986-11-25 Commonwealth Aluminum Corporation Aluminum wettable cathode material for use in aluminum reduction cell
US4526911A (en) * 1982-07-22 1985-07-02 Martin Marietta Aluminum Inc. Aluminum cell cathode coating composition
US4544469A (en) * 1982-07-22 1985-10-01 Commonwealth Aluminum Corporation Aluminum cell having aluminum wettable cathode surface
EP0109358A1 (en) * 1982-11-15 1984-05-23 Schweizerische Aluminium Ag Cathode for a molten bath electrolytic cell
WO1984002723A1 (en) * 1982-12-30 1984-07-19 Eltech Systems Corp Aluminum production cell components
EP0115742A1 (en) * 1982-12-30 1984-08-15 Eltech Systems Corporation Aluminum production cell components
US4481052A (en) * 1983-01-28 1984-11-06 Martin Marietta Corporation Method of making refractory hard metal containing tiles for aluminum cell cathodes
US4544524A (en) * 1983-02-10 1985-10-01 Swiss Aluminium Ltd. Process for manufacturing solid cathodes
US4492670A (en) * 1983-02-10 1985-01-08 Swiss Aluminium Ltd. Process for manufacturing solid cathodes
US4582553A (en) * 1984-02-03 1986-04-15 Commonwealth Aluminum Corporation Process for manufacture of refractory hard metal containing plates for aluminum cell cathodes
EP0375148A2 (en) * 1988-11-17 1990-06-27 Praxair S.T. Technology, Inc. Production of molded refractory shapes
EP0375148A3 (en) * 1988-11-17 1991-05-08 Praxair S.T. Technology, Inc. Production of molded refractory shapes
US5045269A (en) * 1988-11-17 1991-09-03 Union Carbide Coatings Service Technology Corporation Method for sintered shapes with controlled grain size
US6001236A (en) * 1992-04-01 1999-12-14 Moltech Invent S.A. Application of refractory borides to protect carbon-containing components of aluminium production cells
US5310476A (en) * 1992-04-01 1994-05-10 Moltech Invent S.A. Application of refractory protective coatings, particularly on the surface of electrolytic cell components
US5527442A (en) * 1992-04-01 1996-06-18 Moltech Invent S.A. Refractory protective coated electroylytic cell components
US5651874A (en) * 1993-05-28 1997-07-29 Moltech Invent S.A. Method for production of aluminum utilizing protected carbon-containing components
US5683559A (en) * 1994-09-08 1997-11-04 Moltech Invent S.A. Cell for aluminium electrowinning employing a cathode cell bottom made of carbon blocks which have parallel channels therein
US5888360A (en) * 1994-09-08 1999-03-30 Moltech Invent S.A. Cell for aluminium electrowinning
US5753163A (en) * 1995-08-28 1998-05-19 Moltech. Invent S.A. Production of bodies of refractory borides
US6649040B1 (en) 1998-11-17 2003-11-18 Alcan International Limited Wettable and erosion/oxidation-resistant carbon-composite materials
CN102822392A (en) * 2010-03-30 2012-12-12 日本电极株式会社 Cathode carbon block for aluminum smelting purposes, and process for production thereof
EP2554715A1 (en) * 2010-03-30 2013-02-06 Nippon Electrode Co., Ltd. Cathode carbon block for aluminum smelting and process for production thereof
EP2554715A4 (en) * 2010-03-30 2015-03-11 Nippon Electrode Co Ltd Cathode carbon block for aluminum smelting and process for production thereof
CN102822392B (en) * 2010-03-30 2015-07-08 日本电极株式会社 Cathode carbon block for aluminum smelting purposes, and process for production thereof
CN105603462A (en) * 2016-02-25 2016-05-25 周俊和 Process for producing alloy aluminum in electrolytic tank based on electrolytic method
CN105734348A (en) * 2016-02-25 2016-07-06 周俊和 Process for producing alloy aluminum in aluminum electrolysis cell by adopting mix-melting method
CN105821450A (en) * 2016-02-25 2016-08-03 周俊和 Technology for producing alloy aluminum in electrolytic tank based on electrolytic method and aluminum reduction method

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