WO1994024337A1 - Treated carbon or carbon-based cathodic components of aluminium production cells - Google Patents
Treated carbon or carbon-based cathodic components of aluminium production cells Download PDFInfo
- Publication number
- WO1994024337A1 WO1994024337A1 PCT/US1993/011380 US9311380W WO9424337A1 WO 1994024337 A1 WO1994024337 A1 WO 1994024337A1 US 9311380 W US9311380 W US 9311380W WO 9424337 A1 WO9424337 A1 WO 9424337A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- component
- carbon
- colloid
- impregnated
- coated
- Prior art date
Links
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
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5025—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with ceramic materials
- C04B41/5027—Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/52—Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
Definitions
- This invention relates to carbon or carbon-based cathodic cell components of electrolytic cells for the production of aluminium in particular by the electrolysis of alumina in a sodium-containing molten halide electrolyte such as cryolite.
- Aluminium is produced conventionally by the Hall-Héroult process, by the electrolysis of alumina dissolved in cryolite-based molten electrolytes at temperatures up to around 950oC.
- a Hall-Héroult reduction cell typically has a steel shell provided with an insulating lining of refractory material, which in turn has a lining of carbon which contacts the molten constituents.
- Conductor bars connected to the negative pole of a direct current source are embedded in the carbon cathode substrate forming the cell bottom floor.
- the cathode substrate is usually an anthracite based carbon lining made of prebaked cathode blocks, joined with a ramming mixture of anthracite, coke, and coal tar.
- a molten aluminium pool acts as the cathode.
- the carbon lining or cathode material has a useful life of three to eight years, or even less under adverse conditions.
- the deterioration of the cathode bottom is due to erosion and penetration of electrolyte and liquid aluminium as well as intercalation of sodium, which causes swelling and deformation of the cathode carbon blocks and ramming mix.
- the penetration of sodium species and other ingredients of cryolite or air leads to the formation of toxic compounds including cyanides.
- the problems associated with penetration of sodium into the carbon cathode have been extensively studied and discussed in the literature.
- WO/93/20027 proposes applying a protective coating of refractory material to a carbon cathode by applying a micropyretic reaction layer from a slurry containing particulate reactants in a colloidal carrier, and initiating a micropyretic reaction.
- a micropyretic reaction layer from a slurry containing particulate reactants in a colloidal carrier, and initiating a micropyretic reaction.
- a primary object of the present invention is to improve the resistance of carbon cathodes of aluminium production cells or, more generally, of carbon-containing cathodic components of such cells , to the penetration therein of molten electrolyte components and in particular to intercalation by sodium, thereby improving the resistance of the components to degradation during use .
- the invention applies to cathodes or other cathodic cell components made of carbon or other carbon-based microporous materials which have an open porosity which extends to the surfaces of the component which, in use, are exposed to the conditions in the cell .
- carbon cathode is meant to include both pre-formed carbon blocks ready to be assembled into a cathode in the bottom of an aluminium production cell, as well as installed cathodes forming the cell bottom and the carbon side walls extending up from the bottom and which are also cathodlcally polarized and therefore subject to attack by sodium from the molten cell content .
- Other carbon cathodic components include weirs and baffles secured on the cell bottom.
- the invention provides a method of treating carbon-based cathodic components of electrolytic cells for the production of aluminium in particular by the electrolysis of alumina in a sodium-containing molten halide electrolyte such as cryolite, in order to improve their resistance to attack in the aggressive environment in the cells, in particular their resistance to intercalation by sodium.
- the method according to the invention comprises impregnating and/or coating the cathodic cell component with colloidal alumina, ceria, cerium acetate, silica, lithia, yttria , thoria , zirconia, magnesia or monoaluminium phosphate and drying the colloid-impregnated component .
- Colloidal alumina is preferred, and mixtures of colloidal alumina with the other colloids can also be used.
- the method also includes optionally coating the surface of the component, or including in the surface of the component, an aluminium-wettable refractory material, such as titanium diboride.
- an aluminium-wettable refractory material such as titanium diboride.
- the material of the component under the aluminium-wettable refractory material must be impregnated with the colloid, in order to provide an effective barrier to penetration of sodium species.
- the colloid coating may optionally contain aluminium-wettable refractory components such as titanium diboride provided the component is impregnated with colloid in order to provide a barrier to sodium penetration.
- the colloid coating may be devoid of aluminium-wettable refractory components particularly in the case where the component is coated with, for example, "thick" colloidal alumina, in which case the coating already provides a barrier to sodium penetration at the surface and the colloid need not penetrate so deeply into the carbon or carbon-based material.
- Such impregnation and/or coating the carbon or carbon-based component, in particular with colloidal alumina, has been found to improve the resistance of the carbon to damage by sodium impregnation due to the fact that the colloids are stabilized by sodium or other monovalent ions.
- This stabilization which occurs during use of the component in the cathodic environment of the aluminium production cell, makes the diffusion of fresh sodium difficult.
- Such stabilization is particularly effective when the sodium attack occurs through micropores in the carbon or carbon-based material. Therefore, to optimize the protective effect, it is preferred to impregnate the microporoua carbon or carbon-based material with the colloid.
- the colloid impregnation and/or coating prevents or inhibits cryolite penetration due to the fact that sodium impregnation in the surface generally makes the carbon or carbon-based material more w ⁇ ttable by cryolite.
- this enhances wettability of the surface by cryolite, which assists in keeping the cryolite at the surface.
- the enhanced resistance to sodium penetration unexpectedly is associated with an enhanced protection against damage by cryolite penetration.
- the colloid impregnated in the carbon or carbon-containing surface, or coated on the surface improves the resistance of the carbon or carbon-based material to abrasion by sludge that deposits on the cathode surface and may move with the cathodic pool of aluminium and thereby wear the surface.
- the cell efficiency is improved. Because NaF in the electrolyte no longer reacts with the carbon cell bottom and walls, the cell functions with a defined bath ratio without a need to replenish the electrolyte with NaF.
- Impregnation and/or coating of the component is preferably followed by a heat treatment and may also be enhanced by preceding it with a heat treatment, for example at about 1000oC. Sometimes, a single impregnation suffices, but usually the impregnation and drying steps are repeated until the component is saturated with the colloid. Generally, impregnation will take place when the viscosity of the colloid is low, and the number of impregnations needed to saturate the material can be determined by measuring the weight gain. Coating will take place when the the colloid is thicker, i.e. paste-like. Impregnation with a low-viscosity colloid can be followed by coating with a pasty colloid.
- the component is conventionally impregnated by dipping it into the colloid, which can take place in ambient conditions, but the impregnation may be assisted by the application of a pressure differential, by applying pressure or a vacuum. Coating can be by dipping or other application techniques such as brushing.
- the colloid may be derived from colloid precursors and reagents which are solutions of at least one salt such as chlorides, sulfates, nitrates, chlorates, perchlorates or metal organic compounds such as alkoxides, formates, acetates and mixtures thereof.
- the aforementioned solutions of metal organic compounds, principally metal alkoxides, may be of the general formula M(OR) z where M is a metal or complex cation, R is an alkyl chain and z is a number usually from 1 to 12.
- the colloid usually has a dry colloid content corresponding to up to 50 weight% of the colloid plus liquid carrier, preferably from 10 to 20 weight! .
- the liquid carrier is usually water but could be non-aqueous.
- the carbon or carbon-based microporous material making up the cathode or cathodic component usually has an open porosity usually from 5% to 40%, often from about 15% to about 30%.
- Such microporous materials are in particular liable to be attacked by the corrosive cell contents at the high operating temperatures. Impregnation of the pores with a selected colloid greatly increases the materials' resistance to corrosion, as set out above.
- the oarbon or other carbon-based microporous material making up to the cathode or the cathodic component is impregnated with alumina or with colloidal monoalumini ⁇ m phosphate which will be converted to alumina.
- the electrolyte in the aluminium production cell contains cerium, for instance cryolite containing cerium which maintains a protective cerium oxyfluoride coating on the anode
- the carbon-based cathode component may be impregnated and/or coated with a cerium-based colloid, typically comprising at least one of colloidal ceria and colloidal cerium acetate.
- This cerium-based colloidal carrier may further comprise colloidal alumina or other colloids such as yttria, silica, thoria, zirconia, magnesia, lithia and/or monoaluminium phosphate.
- Colloid cerium impregnated in the microporous carbon or carbon-based material improves its performance when used as cathode or cell lining, while the cerium-based colloid is compatible with a cerium-containing fluoride-based electrolyte.
- colloidal lithia One advantageous impregnating agent greatly improving the material's resistance to penetration by sodium from the molten content of the cell, is colloidal lithia.
- the liquid carrier of the colloid preferably colloidal alumina and/or colloidal lithia, is a solution containing at least one compound of lithium, sodium and potassium, preferably a lithium compound.
- Impregnation of carbon cathodes with colloidal lithia and/or with a colloid in a solution of a lithium, sodium or potassium salt, followed by heat treatment greatly improves the cathodes resistance to sodium impregnation, as taught in copending application SN 08/028384 (MOL0515) the contents whereof are incorporated herein by way of reference.
- a colloid impregnated cathode or cathodic component according to the invention can also be coated with a protective coating, typically containing an aluminium-wettable refractory hard metal compound such as the borides and carbides of metals of Group IVB (titanium, zirconium, hafnium) and Group VB (vanadium, niobium, tantalum), usually applied after impregnation of the carbon or carbon-based material with the colloid.
- a protective coating typically containing an aluminium-wettable refractory hard metal compound such as the borides and carbides of metals of Group IVB (titanium, zirconium, hafnium) and Group VB (vanadium, niobium, tantalum), usually applied after impregnation of the carbon or carbon-based material with the colloid.
- Such a protective coating may be formed by applying to the treated carbon cathode a micropyretic reaction layer from a slurry containing particulate reactants in a colloidal carrier, and initiating a micropyretic reaction as described in WO/93/20027, the contents whereof are incorporated herein by way of reference.
- a micropyretic slurry comprises particulate micropyretic reactants in combination with optional particulate of fibrous non-reactant fillers or moderators in a carrier of colloidal materials or other fluids such as water or other aqueous solutions, organic carriers such as acetone, urethanes, etc., or inorganic carriers such as colloidal metal oxides.
- Such coatings may give an additional protection against sodium attack.
- Protective coatings can also be formed from a colloidal slurry of particulate non-reactants, such as preformed TiB 2 , as described in WO/93/20026, the contents whereof are incorporated herein by way of reference.
- Such protective coatings applied directly to a carbon or carbon-based material in a colloidal carrier have good adherence to the substrate and good wettability by molten aluminium.
- aluminium-wettable refractory material such as titanium diboride enhances the penetration of sodium and inhibits the potential beneficial effect of the colloid as a barrier to sodium penetration.
- components coated with aluminium-wettable refractory materials must be impregnated with the colloid in order to inhibit sodium penetration in accordance with the invention.
- the impregnated carbon or carbon-based cathode or cathodic component When the impregnated carbon or carbon-based cathode or cathodic component is coated with a refractory coating forming a cathodic surface in contact with the cathodically-produced aluminium, it can be used as a drained cathode.
- the refractory coating forms the cathodic surface on which the aluminium is deposited cathodically usually with the component arranged upright or at a slope for the aluminium to drain from the cathodic surface.
- low density carbon embraces various types of relatively inexpensive forms of carbon which are relatively porous and very conductive, but hitherto could not be used successfully in the environment of aluminium production cells on account of the fact that they were subject to excessive corrosion or oxidation. Now it is possible, by impregnating these low density carbons with a colloid according to the invention, to make use of them in these cells instead of the more expensive high density anthracite and graphite, taking advantage of their excellent conductivity and low cost.
- the cathode or cathodic components may, for instance, be made of petroleum coke, metallurgical coke, anthracite, graphite, amorphous carbon, fullerene such as fullerene C 60 or C 70 or of a related family, low density carbon or mixtures thereof. Most usually, the component will be made of the usual grades of carbon used as cathodes in conventional Hall-Héroult cells.
- the material making up the component may also be a carbon-based composite material comprising carbon and at least one further component selected from refractory oxycompounds, in particular alumina, and possibly also refractory hard metal borides, carbides and suicides, in particular titanium diboride, it being understood that any aluminium-wettable refractory material will be adjacent to the surface in which case the underlying carbon or carbon-based material will be impregnated with the colloid. Examples of such composite materials are described in copending application PCT/US93/05459(MOL0512) the contents whereof are incorporated herein by way of reference.
- the component of the invention may be a carbon cathode or a carbon cell bottom or lining advantageously impregnated with dried colloidal alumina and coated with a protective coating comprising a Refractory Hard Metal borlde.
- the component may be a carbon cathode or a carbon cell bottom or lining impregnated and coated with dried colloidal alumina.
- a further aspect of the invention is an electrolytic cell for the production of aluminium, in particular by the electrolysis of alumina in a sodium-containing molten halide electrolyte such as cryolite, comprising a cathodic component made of carbon or a carbon-based material, wherein the component is impregnated and/or coated with colloidal alumina, ceria, cerium acetate, silica, lithia, yttria, thoria, zirconia, magnesia or monoaluminium phosphate, as set out above.
- a cathodic component made of carbon or a carbon-based material
- the invention also concerns a method of producing aluminium by the electrolysis of alumina dissolved in molten cryolite in a cell having a colloid impregnated and/or coated carbon cathode as set out above; an electrolytic cell for producing aluminium by the electrolysis of alumina dissolved in molten cryolite provided with such a colloid impregnated and/or coated carbon; a method of conditioning carbon cathodes for use in such cells; as well as a method of reconditioning these electrolytic cells.
- the electrolyte may be cryolite or modified forms of cryolite in particular containing LiF, and may be at the usual operating temperature of about 950oC, or lower temperatures.
- the impregnated samples showed a higher resistance to sodium penetration than the non-impregnated samples which showed signs of substantial degradation after only about 3 hours .
- Example 1 Several of the colloid-impregnated samples of Example 1 were further coated with a TiB2 coating as follows.
- a slurry was prepared from a dispersion of 10g TiB 2 , 99.5% pure, -325 mesh ( ⁇ 42 micrometer), in 25ml of colloidal alumina containing about 20 weight% of solid alumina. Coatings with a thickness of 150 ⁇ S0 to 500 ⁇ 50 micrometer were applied to the faces of carbon blocks. Each layer of slurry was allowed to dry for several minutes before applying the next, followed by a final drying by baking in an oven at 100-150oC for 30 minutes to 1 hour.
- the colloid-impregnated TiB 2 -coated samples showed an even higher resistance to sodium penetration than the colloid-impregnated uncoated samples, when submitted to the same sodium penetration test. These coated samples additionally exhibited improved wettability by molten aluminium. Compared to non-impregnated samples coated in the same way, the impregnated and coated samples showed a better resistance to sodium penetration.
- the particulate mixture was made of 84 wt% petroleum coke (1-200 micrometer), 15wt% AI 2 O 3 (3 micrometer) and lwt% B 2 O 3 (1 micrometer).
- colloidal alumina (AL-20 grade, 20% solid alumina) was added to the dried acidified petroleum coke based mixture and stirred well.
- the resulting slurry of petroleum coke, particulate alumina, colloid alumina and HCl mixture was then dried at 200oC in an air furnace for approximately 2 to 3 hours to produce a paste.
- the resulting paste was pressed at 57 mPa into cylinder form. In the pressing process, some liquid was squeezed out.
- the cylinders were then held at 200oC in an air furnace until dried.
- the resulting material was a microporous carbon/alumina composite.
- a specimen produced this way was impregnated with colloidal cerium acetate by dipping the dried cylinder in the colloid, then drying it again at 200oC.
- impregnated cylinders prepared this way were found to have enhanced resistance to sodium penetration when used as cathodes in a laboratory scale aluminium production cell.
- liquid carrier of the colloid at least one compound of lithium, aluminium, cerium, calcium, sodium and/or potassium, preferably a soluble compound.
- the lithium compound may be lithium acetate, lithium carbonate, lithium fluoride, lithium chloride, lithium oxalate, lithium nitride, lithium nitrate, lithium formate and lithium aryl, lithium tetraborate and mixtures thereof.
- the aluminium compound is preferably a soluble compound, but some insoluble compounds can also be used.
- Soluble compounds include aluminium nitrate, carbonate, halides and borate. Insoluble aluminium carbide can also be used.
- these lithium compounds there is at least one of these lithium compounds together with at least one of these aluminium compounds .
- These compounds react together and, when the component is made of carbon, with the carbon to form aluminium oxy carbide and/or aluminium carbide AI 4 C which act as an oxidation-resistant and electrically-conductive binder for the carbon and contribute to the great oxidation resistance of the material and make it wettable by molten cryolite.
- AI 4 C aluminium oxy carbide and/or aluminium carbide
- the addition of these lithium and aluminium compounds greatly increases the stability of the material in the environment of an aluminium production cell.
- a solution can be prepared by thoroughly mixing 5g of AlNO 3 .9H 2 O(98%) and 5g of LiNO 3 (99%) in 50ml of water, and this carrier solution then mixed with colloidal alumina to provide a solid alumina colloid content of about 10 to 20 weight% of the total.
- Cathode grades of carbon impregnated with this reagent-containing colloidal alumina followed by heat treatment at about 1000°C show improved stability and greater resistance to penetration by sodium.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Metallurgy (AREA)
- Inorganic Chemistry (AREA)
- Electrochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrolytic Production Of Metals (AREA)
- Carbon And Carbon Compounds (AREA)
- Catalysts (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002160468A CA2160468C (en) | 1993-04-19 | 1993-11-23 | Treated carbon or carbon-based cathodic components of aluminium production cells |
EP94901664A EP0786020A1 (en) | 1993-04-19 | 1993-11-23 | Treated carbon or carbon-based cathodic components of aluminium production cells |
SK1280-95A SK128095A3 (en) | 1993-04-19 | 1993-11-23 | Treated carbon or carbon-based cathodic components for cells for production of aluminium |
AU56172/94A AU674718B2 (en) | 1993-04-19 | 1993-11-23 | Treated carbon or carbon-based cathodic components of aluminium production cells |
US08/532,785 US5679224A (en) | 1993-11-23 | 1993-11-23 | Treated carbon or carbon-based cathodic components of aluminum production cells |
NO954159A NO954159D0 (en) | 1993-04-19 | 1995-10-18 | Treated carbon or carbon based cathodic components for aluminum production cells |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US9303683 | 1993-04-19 | ||
USPCT/US93/03683 | 1993-04-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994024337A1 true WO1994024337A1 (en) | 1994-10-27 |
Family
ID=22236520
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1993/011380 WO1994024337A1 (en) | 1993-04-19 | 1993-11-23 | Treated carbon or carbon-based cathodic components of aluminium production cells |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0786020A1 (en) |
AU (1) | AU674718B2 (en) |
CA (1) | CA2160468C (en) |
NO (1) | NO954159D0 (en) |
PL (1) | PL311207A1 (en) |
SK (1) | SK128095A3 (en) |
WO (1) | WO1994024337A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5676807A (en) * | 1992-06-12 | 1997-10-14 | Moltech Invent S.A. | Carbon containing ramming paste in aluminum production cells |
US5679224A (en) * | 1993-11-23 | 1997-10-21 | Moltech Invent S.A. | Treated carbon or carbon-based cathodic components of aluminum production cells |
WO1998017843A1 (en) * | 1996-10-18 | 1998-04-30 | Moltech Invent S.A. | The start-up of aluminium electrowinning cells |
US5876584A (en) * | 1995-05-26 | 1999-03-02 | Saint-Gobain Industrial Ceramics, Inc. | Method of producing aluminum |
Citations (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3457158A (en) * | 1964-10-02 | 1969-07-22 | Reynolds Metals Co | Cell lining system |
US3558450A (en) * | 1968-06-24 | 1971-01-26 | Phillips Petroleum Co | Process for electrochemical conversion |
US4292345A (en) * | 1980-02-04 | 1981-09-29 | Kolesnik Mikhail I | Method of protecting carbon-containing component parts of metallurgical units from oxidation |
US4376690A (en) * | 1980-05-23 | 1983-03-15 | Swiss Aluminium Ltd. | Cathode for a cell for fused salt electrolysis |
US4439382A (en) * | 1981-07-27 | 1984-03-27 | Great Lakes Carbon Corporation | Titanium diboride-graphite composites |
US4466996A (en) * | 1982-07-22 | 1984-08-21 | Martin Marietta Corporation | Aluminum cell cathode coating method |
US4534837A (en) * | 1983-06-20 | 1985-08-13 | Solvay & Cie | Process for the manufacture of an electrode for electrochemical processes and a cathode for the electrolytic production of hydrogen |
US4599320A (en) * | 1982-12-30 | 1986-07-08 | Alcan International Limited | Refractory lining material for electrolytic reduction cell for aluminum production and method of making the same |
US4600481A (en) * | 1982-12-30 | 1986-07-15 | Eltech Systems Corporation | Aluminum production cell components |
US4683037A (en) * | 1985-05-17 | 1987-07-28 | Eltech Systems Corporation | Dimensionally stable anode for molten salt electrowinning and method of electrolysis |
US4726995A (en) * | 1985-11-13 | 1988-02-23 | Union Carbide Corporation | Oxidation retarded graphite or carbon electrode and method for producing the electrode |
US4921731A (en) * | 1986-02-25 | 1990-05-01 | University Of Florida | Deposition of ceramic coatings using sol-gel processing with application of a thermal gradient |
US4935265A (en) * | 1988-12-19 | 1990-06-19 | United Technologies Corporation | Method for coating fibers with an amorphous hydrated metal oxide |
US4944991A (en) * | 1988-07-08 | 1990-07-31 | Electric Power Research Institute | Formation of alumina impregnated carbon fiber mats |
US5071533A (en) * | 1987-09-16 | 1991-12-10 | Moltech Invent S.A. | Cathode current collector for aluminum cells |
US5071674A (en) * | 1989-11-30 | 1991-12-10 | The University Of Florida | Method for producing large silica sol-gels doped with inorganic and organic compounds |
US5137749A (en) * | 1989-12-20 | 1992-08-11 | Central Glass Company, Limited | Method of forming metal oxide film by using metal alkoxide solution |
US5203971A (en) * | 1987-09-16 | 1993-04-20 | Moltech Invent S.A. | Composite cell bottom for aluminum electrowinning |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1993020026A1 (en) * | 1992-04-01 | 1993-10-14 | Moltech Invent Sa | Prevention of oxidation of carbonaceous and other materials at high temperatures |
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 |
-
1993
- 1993-11-23 EP EP94901664A patent/EP0786020A1/en not_active Ceased
- 1993-11-23 AU AU56172/94A patent/AU674718B2/en not_active Ceased
- 1993-11-23 SK SK1280-95A patent/SK128095A3/en unknown
- 1993-11-23 PL PL93311207A patent/PL311207A1/en unknown
- 1993-11-23 WO PCT/US1993/011380 patent/WO1994024337A1/en not_active Application Discontinuation
- 1993-11-23 CA CA002160468A patent/CA2160468C/en not_active Expired - Fee Related
-
1995
- 1995-10-18 NO NO954159A patent/NO954159D0/en not_active Application Discontinuation
Patent Citations (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3457158A (en) * | 1964-10-02 | 1969-07-22 | Reynolds Metals Co | Cell lining system |
US3558450A (en) * | 1968-06-24 | 1971-01-26 | Phillips Petroleum Co | Process for electrochemical conversion |
US4292345A (en) * | 1980-02-04 | 1981-09-29 | Kolesnik Mikhail I | Method of protecting carbon-containing component parts of metallurgical units from oxidation |
US4376690A (en) * | 1980-05-23 | 1983-03-15 | Swiss Aluminium Ltd. | Cathode for a cell for fused salt electrolysis |
US4439382A (en) * | 1981-07-27 | 1984-03-27 | Great Lakes Carbon Corporation | Titanium diboride-graphite composites |
US4466996A (en) * | 1982-07-22 | 1984-08-21 | Martin Marietta Corporation | Aluminum cell cathode coating method |
US4600481A (en) * | 1982-12-30 | 1986-07-15 | Eltech Systems Corporation | Aluminum production cell components |
US4599320A (en) * | 1982-12-30 | 1986-07-08 | Alcan International Limited | Refractory lining material for electrolytic reduction cell for aluminum production and method of making the same |
US4534837A (en) * | 1983-06-20 | 1985-08-13 | Solvay & Cie | Process for the manufacture of an electrode for electrochemical processes and a cathode for the electrolytic production of hydrogen |
US4683037A (en) * | 1985-05-17 | 1987-07-28 | Eltech Systems Corporation | Dimensionally stable anode for molten salt electrowinning and method of electrolysis |
US4726995A (en) * | 1985-11-13 | 1988-02-23 | Union Carbide Corporation | Oxidation retarded graphite or carbon electrode and method for producing the electrode |
US4921731A (en) * | 1986-02-25 | 1990-05-01 | University Of Florida | Deposition of ceramic coatings using sol-gel processing with application of a thermal gradient |
US5071533A (en) * | 1987-09-16 | 1991-12-10 | Moltech Invent S.A. | Cathode current collector for aluminum cells |
US5203971A (en) * | 1987-09-16 | 1993-04-20 | Moltech Invent S.A. | Composite cell bottom for aluminum electrowinning |
US4944991A (en) * | 1988-07-08 | 1990-07-31 | Electric Power Research Institute | Formation of alumina impregnated carbon fiber mats |
US4935265A (en) * | 1988-12-19 | 1990-06-19 | United Technologies Corporation | Method for coating fibers with an amorphous hydrated metal oxide |
US5071674A (en) * | 1989-11-30 | 1991-12-10 | The University Of Florida | Method for producing large silica sol-gels doped with inorganic and organic compounds |
US5137749A (en) * | 1989-12-20 | 1992-08-11 | Central Glass Company, Limited | Method of forming metal oxide film by using metal alkoxide solution |
Non-Patent Citations (1)
Title |
---|
See also references of EP0786020A4 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5676807A (en) * | 1992-06-12 | 1997-10-14 | Moltech Invent S.A. | Carbon containing ramming paste in aluminum production cells |
US5679224A (en) * | 1993-11-23 | 1997-10-21 | Moltech Invent S.A. | Treated carbon or carbon-based cathodic components of aluminum production cells |
US5876584A (en) * | 1995-05-26 | 1999-03-02 | Saint-Gobain Industrial Ceramics, Inc. | Method of producing aluminum |
WO1998017843A1 (en) * | 1996-10-18 | 1998-04-30 | Moltech Invent S.A. | The start-up of aluminium electrowinning cells |
Also Published As
Publication number | Publication date |
---|---|
NO954159L (en) | 1995-10-18 |
AU5617294A (en) | 1994-11-08 |
PL311207A1 (en) | 1996-02-05 |
EP0786020A4 (en) | 1997-07-30 |
NO954159D0 (en) | 1995-10-18 |
AU674718B2 (en) | 1997-01-09 |
EP0786020A1 (en) | 1997-07-30 |
CA2160468A1 (en) | 1994-10-27 |
SK128095A3 (en) | 1996-03-06 |
CA2160468C (en) | 2001-10-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0892085B1 (en) | Drained cathode aluminium production cells | |
US6139704A (en) | Application of refractory borides to protect carbon-containing components of aluminum production cells | |
US5534130A (en) | Application of phosphates of aluminum to carbonaceous components of aluminum production cells | |
US5378327A (en) | Treated carbon cathodes for aluminum production, the process of making thereof and the process of using thereof | |
US6001236A (en) | Application of refractory borides to protect carbon-containing components of aluminium production cells | |
US5578174A (en) | Conditioning of cell components for aluminum production | |
AU674718B2 (en) | Treated carbon or carbon-based cathodic components of aluminium production cells | |
US6616829B2 (en) | Carbonaceous cathode with enhanced wettability for aluminum production | |
US5651874A (en) | Method for production of aluminum utilizing protected carbon-containing components | |
US5679224A (en) | Treated carbon or carbon-based cathodic components of aluminum production cells | |
US5534119A (en) | Method of reducing erosion of carbon-containing components of aluminum production cells | |
US20040149569A1 (en) | Aluminium-wettable porous ceramic material | |
AU701370B2 (en) | Maintaining protective surfaces on carbon cathodes in aluminium electrowinning cells | |
US5728466A (en) | Hard and abrasion resistant surfaces protecting cathode blocks of aluminium electrowinning cells | |
EP1693486B1 (en) | A method for providing a protective coating for carbonaceous components of an electrolysis cell | |
AU2002236143A1 (en) | Aluminium-wettable porous ceramic material |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AU BR CA CZ FI HU JP KP KR NO NZ PL RO RU SK UA US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 1994901664 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 08532785 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2160468 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 128095 Country of ref document: SK |
|
WWP | Wipo information: published in national office |
Ref document number: 1994901664 Country of ref document: EP |
|
WWR | Wipo information: refused in national office |
Ref document number: 1994901664 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1994901664 Country of ref document: EP |