EP1366214B1 - Aluminium-wettable porous ceramic material - Google Patents
Aluminium-wettable porous ceramic material Download PDFInfo
- Publication number
- EP1366214B1 EP1366214B1 EP02702625A EP02702625A EP1366214B1 EP 1366214 B1 EP1366214 B1 EP 1366214B1 EP 02702625 A EP02702625 A EP 02702625A EP 02702625 A EP02702625 A EP 02702625A EP 1366214 B1 EP1366214 B1 EP 1366214B1
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- EP
- European Patent Office
- Prior art keywords
- aluminium
- metal
- cell
- cathode
- component
- 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.)
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- 229910010293 ceramic material Inorganic materials 0.000 title claims abstract description 25
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 178
- 239000004411 aluminium Substances 0.000 claims abstract description 177
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 176
- 229910052751 metal Inorganic materials 0.000 claims abstract description 76
- 239000002184 metal Substances 0.000 claims abstract description 76
- 239000000919 ceramic Substances 0.000 claims abstract description 61
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000003792 electrolyte Substances 0.000 claims abstract description 43
- 238000000576 coating method Methods 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 33
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 33
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 33
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 31
- 239000011248 coating agent Substances 0.000 claims abstract description 26
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000000203 mixture Substances 0.000 claims abstract description 20
- 229910052742 iron Inorganic materials 0.000 claims abstract description 16
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 12
- 239000002344 surface layer Substances 0.000 claims abstract description 12
- 229910052802 copper Inorganic materials 0.000 claims abstract description 11
- 239000010949 copper Substances 0.000 claims abstract description 11
- 238000005363 electrowinning Methods 0.000 claims abstract description 11
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 8
- 239000010941 cobalt Substances 0.000 claims abstract description 8
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 7
- 239000011701 zinc Substances 0.000 claims abstract description 7
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 5
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims abstract description 4
- 239000002245 particle Substances 0.000 claims description 25
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 18
- 239000002002 slurry Substances 0.000 claims description 18
- 239000010410 layer Substances 0.000 claims description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 13
- 150000004767 nitrides Chemical class 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 239000002131 composite material Substances 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000003381 stabilizer Substances 0.000 claims description 8
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 6
- 239000007769 metal material Substances 0.000 claims description 6
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 6
- QYEXBYZXHDUPRC-UHFFFAOYSA-N B#[Ti]#B Chemical compound B#[Ti]#B QYEXBYZXHDUPRC-UHFFFAOYSA-N 0.000 claims description 5
- 229910033181 TiB2 Inorganic materials 0.000 claims description 5
- 239000011575 calcium Substances 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 5
- 238000005304 joining Methods 0.000 claims description 5
- 239000011777 magnesium Substances 0.000 claims description 5
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 5
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 4
- 150000004645 aluminates Chemical class 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910017083 AlN Inorganic materials 0.000 claims description 3
- 229910017109 AlON Inorganic materials 0.000 claims description 3
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 claims description 3
- 229910052582 BN Inorganic materials 0.000 claims description 3
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- 229910003564 SiAlON Inorganic materials 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 3
- 150000001247 metal acetylides Chemical class 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 3
- 230000003014 reinforcing effect Effects 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 2
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 229910001947 lithium oxide Inorganic materials 0.000 claims description 2
- 239000000395 magnesium oxide Substances 0.000 claims description 2
- 239000002243 precursor Substances 0.000 claims description 2
- ZCUFMDLYAMJYST-UHFFFAOYSA-N thorium dioxide Chemical compound O=[Th]=O ZCUFMDLYAMJYST-UHFFFAOYSA-N 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 claims description 2
- 239000011787 zinc oxide Substances 0.000 claims description 2
- -1 alumina Chemical compound 0.000 abstract description 3
- 210000004027 cell Anatomy 0.000 description 73
- 238000004519 manufacturing process Methods 0.000 description 14
- 239000011148 porous material Substances 0.000 description 12
- 239000011159 matrix material Substances 0.000 description 9
- 239000006260 foam Substances 0.000 description 8
- 210000003850 cellular structure Anatomy 0.000 description 6
- 229910052593 corundum Inorganic materials 0.000 description 6
- 238000007598 dipping method Methods 0.000 description 6
- 229910001845 yogo sapphire Inorganic materials 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 230000000717 retained effect Effects 0.000 description 5
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 4
- 229920005830 Polyurethane Foam Polymers 0.000 description 4
- 238000004090 dissolution Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005868 electrolysis reaction Methods 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 239000002923 metal particle Substances 0.000 description 4
- 239000011496 polyurethane foam Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- 239000003575 carbonaceous material Substances 0.000 description 3
- 239000010406 cathode material Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 238000011065 in-situ storage Methods 0.000 description 3
- 230000008595 infiltration Effects 0.000 description 3
- 238000001764 infiltration Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 238000009736 wetting Methods 0.000 description 3
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminium flouride Chemical compound F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 2
- 239000005751 Copper oxide Substances 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 2
- 239000003830 anthracite Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 229910000431 copper oxide Inorganic materials 0.000 description 2
- 229910001610 cryolite Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 210000002287 horizontal cell Anatomy 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 229910000505 Al2TiO5 Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 241000640882 Condea Species 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 238000009626 Hall-Héroult process Methods 0.000 description 1
- 229910004541 SiN Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- UQZIWOQVLUASCR-UHFFFAOYSA-N alumane;titanium Chemical compound [AlH3].[Ti] UQZIWOQVLUASCR-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 239000011285 coke tar Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 229910021426 porous silicon Inorganic materials 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000002940 repellent Effects 0.000 description 1
- 239000005871 repellent Substances 0.000 description 1
- 238000009738 saturating Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
Images
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
- 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
- C25C3/085—Cell construction, e.g. bottoms, walls, cathodes characterised by its non electrically conducting heat insulating parts
Definitions
- the invention relates to a ceramic material which can be utilised for the manufacture of aluminium-wettable and aluminium-wetted ceramic components, in particular for use in aluminium production, for example as cathodes, sidewalls and other cell components which during use are exposed to molten aluminium, electrolyte and/or corrosive gases.
- 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 950°C.
- 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 and corrosive gases.
- Conductor bars connected to the negative pole of a direct current source are embedded in the carbon cathode forming the cell bottom floor.
- the cathode is usually an anthracite based carbon lining made of prebaked cathode blocks, joined with a ramming mixture of anthracite, coke and coal tar, or with glue.
- US Patent 5,981,081 discloses wear and corrosion resistant coatings made of transition metal boride particles dispersed in a matrix of nickel, cobalt or iron. The coatings are applied by explosion or plasma spraying a mixture of powders of a transition metal boride and a boron containing alloy on a metal substrate and heat treating.
- US Patent 4,560,448 (Sane/Wheeler/Kuivila) discloses a porous component made of aluminium repellent material covered with an aluminium-wettable metal boride coating which during use is maintained by saturating the molten aluminium infiltrating the porous component with coating constituents.
- US Patent 4,650,552 (de Nora/Gauger/Fresnel/Adorian/Duruz), discloses an aluminium production cell component produced from a powder mixture of alumina and aluminium.
- US Patent 4,600,481 (Sane/Wheeler/Gagescu/Debely/Adorian/Derivaz) discloses a component of an aluminium production cell which is made of an openly porous matrix, e.g. an alumina matrix, filled with molten aluminium.
- the openly porous matrix may comprise an aluminium-wettable coating made of a boride or nickel.
- the infiltration of the matrix with aluminium is carried out at a temperature of 1000° to 1500°C.
- US Patent 5,007,475 discloses a ceramic structure, e.g. alumina, infiltrated by molten aluminium with the aid of an infiltration enhancer consisting of a metal/gas combination selected from Mg/N, Sr/N, Zn/O and Ca/N to which the alumina structure is exposed before and during infiltration.
- an infiltration enhancer consisting of a metal/gas combination selected from Mg/N, Sr/N, Zn/O and Ca/N to which the alumina structure is exposed before and during infiltration.
- An object of the invention is to provide an aluminium-wettable component for a cell for the production of aluminium from alumina dissolved in a fluoride-based molten electrolyte.
- Another object of the invention is to provide an aluminium-wetted component which is highly conductive and resistant to molten electrolyte for use as a cathode in a drained cell or in a cell operating with a shallow or deep aluminium pool or as a cell sidewall or another component which is exposed to molten aluminium, electrolyte and/or corrosive gases, or as a lining for protecting other cell components against molten electrolyte, or for making other cell components aluminium-wettable.
- a further object of the invention is to provide an aluminium-wettable or aluminium-wetted component which can be made from readily available materials.
- Yet another object of the invention is to provide an aluminium-wettable component which can be wetted with aluminium outside an aluminium production cell or in-situ by exposure to cathodic molten aluminium.
- Another object of the invention is to provide an aluminium-wetted component that retains its protective and wettability properties even when exposed to highly oxidising and/or corrosive environments.
- Yet a further object of the invention is to provide a ceramic-based or a ceramic-metal material which can be used in an oxidising and/or corrosive media at elevated temperature.
- a first aspect of the invention relates to an aluminium-wettable component of a cell for the electrowinning of aluminium from alumina dissolved in a fluoride-based molten electrolyte.
- the component comprises an openly porous or reticulated ceramic structure whose surface during use is exposed to and wetted by molten aluminium.
- the structure is made of a ceramic material inert and resistant to molten aluminium and an aluminium-wettable material that comprises metal oxide and/or partly oxidised metal which is/are readable with molten aluminium to form a surface layer containing alumina, aluminium and metal derived from the metal oxide and/or partly oxidised metal.
- the inert and resistant ceramic material may comprise at least one oxide selected from oxides of aluminium, zirconium, tantalum, titanium, silicon, niobium, magnesium and calcium and mixtures thereof, as a simple oxide and/or in a mixed oxide, for example an aluminate of zinc (ZnAlO 4 ) or titanium (TiAlO 5 ).
- suitable inert and resistant ceramic materials can be selected amongst nitrides, carbides and borides and oxycompounds, such as aluminium nitride, AlON, SiAlON, boron nitride, silicon nitride, silicon carbide, aluminium borides, alkali earth metal zirconates and aluminates, and their mixtures.
- the reaction of the metal oxide and/or partly oxidised metal with molten aluminium involves the reduction of the metal oxide and/or partly oxidised metal and the oxidation of aluminium.
- the metal oxide and/or partly oxidised metal to be reducible by molten aluminium, it is necessary that such a metal be more electronegative than aluminium.
- the metal of the metal oxide and/or partly oxidised metal reducible by molten aluminium is selected from manganese, iron, cobalt, nickel, copper and zinc and combinations thereof.
- the concentration of reactable metal oxide and/or partly oxidised metal at the surface of the ceramic structure affects the speed at which the structure is wetted by molten aluminium.
- the surface of the ceramic structure should contain the reactable metal oxide and/or partly oxidised metal in an amount of at least 2 to 3 weight%, preferably at least 5 to 25 weight% of the material making the surface of the ceramic structure.
- the coating may comprise much more metal oxide and/or partly oxidised metal, e.g. up to 50 or even 80 weight% or possibly even more.
- the electronegativity of the metal of the reactable metal oxide and/or partly oxidised metal also affects the speed of aluminium wetting. The fastest wetting of the ceramic structure is achieved when the metal of the reactable metal oxide and/or partly oxidised metal is selected from copper, nickel, cobalt, manganese and iron.
- the openly porous or reticulated ceramic structure comprises a coating of the aluminium-wettable material on the inert and resistant ceramic, material.
- the openly porous or reticulated ceramic structure consists of a skeleton of the inert and resistant ceramic material coated with the aluminium-wettable material.
- Such aluminium-wettable coating is usually a slurry-applied coating comprising particles of the metal oxide and/or partly oxidised metal reactable with molten aluminium in a dried colloidal carrier selected from alumina, ceria, lithia, magnesia, silica, thoria, yttria, zirconia, titanium oxide and zinc oxide, and precursors and mixtures thereof. Further details of such slurry-applied coatings are disclosed in WO01/42168 (de Nora/Duruz), which describes such coatings on solid substrates.
- the slurry-applied aluminium-wettable coating may further comprise particles of at least one compound selected from metal borides, carbides and nitrides.
- the aluminium-wettable coating comprises the particles of the metal oxide and/or partly oxidised metal reactable with molten aluminium and particles of titanium diboride in dried colloidal alumina.
- Particles of the metal boride, carbide or nitride may be covered with mixed oxides of metal derived from the dried colloidal carrier and metal derived from the metal boride, carbide or nitride.
- the slurry-applied aluminium-wettable coating can be obtained from a slurry comprising metal oxide particles that combine upon heat treatment with metal derived from the dried colloidal carrier to form mixed oxides which are miscible with the mixed oxides covering the particles of the metal boride, carbide or nitride.
- Suitable slurries producing such a coating are disclosed in WO01/42531 (Nguyen/Duruz/de Nora), which describes such coatings on solid substrates.
- the openly porous ceramic structure is made of a composition which comprises a mixture of the inert and resistant ceramic material and the aluminium-wettable ceramic material.
- a ceramic structure should comprise a sufficient amount of inert and resistant ceramic material that upon contact/reaction of the aluminium-wettable ceramic material with molten aluminium, the overall ceramic structure retains sufficient mechanical properties.
- the aluminium-wettable material makes up less than 15 weight%, usually less than 10 weight%, of the ceramic structure.
- the openly porous ceramic structure may be formed on a reinforcing metal skeleton, in particular a metal mat.
- Suitable metals for such a skeleton include iron and iron alloys and other metals which are mechanically resistant at elevated temperature.
- a component made of the ceramic structure for instance to secure the ceramic structure on the bottom of an aluminium production cell as disclosed in Figs. 2 and 3 of US Patent 5,651,874 (de Nora/Sekhar).
- the internal inserts may be made of iron or iron alloys or other heavy materials.
- a reinforcing metal can also act as ballast.
- the component of the invention has numerous applications some of which are set out hereafter.
- the component may be a cathode or a cathode lining, for example plate- or wedge-shaped, on a cathode body, in particular made of carbon material.
- the component can also be an aluminium pool stabiliser in the form of a plate having a density which is either lower than that of molten aluminium so that it can float at the surface of the aluminium pool, or higher than that of molten aluminium so that it can rest at the bottom of the aluminium pool. All of the aforementioned components, which are exposed during use to the product aluminium, can be placed as such in the cell and wetted during use.
- Such components may be top coated with a highly aluminium-webtable start-up layer, for example as disclosed in WO01/42168 (de Nora/Duruz).
- the aluminium-wettable component can constitute a skeleton which can be infiltrated with molten aluminium to form for example a cell sidewall or a sidewall lining, or a wedge-shaped connecting body for joining the surface of a cell bottom to an adjacent sidewall at the periphery of the cell bottom.
- the invention also relates to an aluminium-wetted component of a cell for the electrowinning of aluminium.
- the aluminium-wetted component comprises an openly porous or reticulated ceramic structure which has a surface layer containing alumina, aluminium and another metal, e.g. iron, copper or nickel.
- Such component is obtainable by exposing to molten aluminium an openly porous or reticulated aluminium-wettable component made of ceramic material inert and resistant to molten aluminium, e.g. alumina, and an aluminium-wettable material that comprises metal oxide and/or partly oxidised metal, e.g. iron, copper or nickel as oxides and/or partly oxidised metals, which is/are reactable with molten aluminium as described above.
- the component comprises an openly porous or reticulated ceramic structure whose surface during use is exposed to and wetted by molten aluminium.
- the structure is made of a ceramic material inert and resistant to molten aluminium and an aluminium-wettable material that comprises metal oxide and/or partly oxidised metal which is/are reactable with molten aluminium to form a surface layer containing alumina, aluminium and metal derived from the metal oxide and/or partly oxidised metal.
- aluminium-wetted components are completely filled and covered with aluminium that shields their openly porous or reticulated ceramic structure from exposure to molten electrolyte and/or corrosive gases during use.
- the aluminium-wetted component may be a cathode or a cathode lining or an aluminium pool stabiliser wetted by aluminium before or during use.
- the component may be a cell sidewall or a sidewall lining or a wedge-shaped body for joining the surface of a cell bottom to an adjacent sidewall, all wetted by aluminium before use.
- Another aspect'of the invention is a cell for the electrowinning of aluminium from alumina dissolved in a fluoride-based electrolyte, comprising one or more aluminium-wettable and/or aluminium-wetted components described above.
- the cell may in particular comprise a cathode or a cathode body whose surface is lined with a cathode lining as disclosed above.
- the cathode body and the cathode lining may be joined through a bonding layer, in particular a slurry-applied refractory boride layer as disclosed in WO01/42168 (de Nora/Duruz) and WO01/42531 (Nguyen/Duruz/de Nora).
- the lined cathode surface is part of a horizontal or inclined cathode bottom, in particular a horizontal cathode bottom lined with a wedge-like cathode lining forming an aluminium-wettable drained sloping cathode surface thereon.
- the cathode body may be located above a cell bottom that is arranged to collect molten aluminium produced on and drained from the cathode lining.
- One further aspect of the invention relates to a composite ceramic-based material which comprises an openly porous or reticulated ceramic structure whose surface during use is exposed to and wetted by molten aluminium.
- This structure is made of a ceramic material inert and resistant to molten aluminium and an aluminium-wettable material that comprises metal oxide and/or partly oxidised metal selected from partly oxidised or oxide of copper, nickel, cobalt, manganese and iron and mixtures thereof, which is/are reactable with molten aluminium to form a surface layer containing alumina, aluminium and metal derived from the metal oxide and/or partly oxidised metal.
- Such a material may be used, for instance, for the manufacture of components or linings of apparatus for treating molten aluminium, in particular for purifying molten aluminium or separating alloying metals from an aluminium alloy. Further details of such apparatus can be found in WO00/63630 (Holz/Duruz).
- a yet further aspect of the invention relates to a composite ceramic-metal material which comprises, as before, an openly porous or reticulated ceramic structure which has a surface layer containing alumina, aluminium and another metal.
- the composite ceramic-metal material is obtainable by exposing to molten aluminium a composite material made of a ceramic material inert and resistant to molten aluminium and an aluminium-wettable material that comprises a metal oxide and/or a partly oxidised metal selected from copper, nickel, cobalt, manganese and iron and mixtures thereof, which is/are reactable with molten aluminium to form a surface layer containing alumina, aluminium and metal derived from the metal oxide and/or partly oxidised metal.
- Such a material may be used for the manufacture of aluminium-wetted components for applications in high temperature oxidising or corrosive gases, in particular oxygen and/or fluorine-containing gases, or liquids, such as fluorine-containing liquids or molten metal, in particular molten aluminium.
- gases in particular oxygen and/or fluorine-containing gases
- liquids such as fluorine-containing liquids or molten metal, in particular molten aluminium.
- the aluminium-wetted components may be used in apparatus for treating molten aluminium.
- the components may also be used at temperatures below the melting point of aluminium as electrodes, heating elements, structural materials, metallurgical crucibles for containing molten metals other than aluminium, anodes, furnace fixtures, molds etc. Due to the capacity of the ceramic structure to retain molten aluminium within its pores and on its surface by capillary effect, the aluminium-wetted components may be used in chemically aggressive environments at temperatures above the melting point of aluminium, for instance as linings in furnaces, providing the components are not exposed to substantial mechanical wear.
- Figure 1 shows an aluminium production cell of drained configuration.
- the cell comprises non-carbon metal-based anodes 10, for example as disclosed in WO00/40781 and WO00/40782 (both in the name of de Nora), which are spaced apart from correspondingly sloped facing cathode surfaces 20, for example as disclosed in WO00/63463 (de Nora), in a fluoride-based molten electrolyte 5.
- the cell bottom 25,25' for example made of carbon material, is covered with aluminium-wetted cathode linings 21,21' which form drained aluminium-wetted sloping cathode surfaces 20 according to the invention, different embodiments being shown in the right and the left hand part of Figure 1.
- the cathode surfaces 20 slope down towards the middle of the cell bottom 25,25'.
- the cell bottom 25 is horizontal whereas the cathode lining 21' covering it is a wedge with a small angle forming a sloping cathode surface 20 above the horizontal cell bottom 25.
- the cell bottom 25' is at a slope and covered with cathode lining plates (tiles) 21 of uniform thickness and which form a sloping cathode surface 20 parallel to the sloping cell bottom 25'.
- the cell bottom 25,25' is only partly covered with the cathode lining 21,21', leaving a central channel 30 formed by the cell bottom 25,25' and the adjacent cathode linings 21,21' which are spaced in the middle of the cell by channel 30.
- This channel 30 serves to collect product molten aluminium 60 from the sloping cathode surfaces 20.
- the cell bottom 25,25', in particular where it forms part of the aluminium-collection channel is preferably protected with an aluminium wettable layer 35, for example a slurry-applied refractory boride layer as disclosed in WO01/42168 (de Nora/Duruz) or WO01/42531 (Nguyen/Duruz/de Nora).
- a slurry-applied layer 35 is also wetted by molten aluminium 22 that wets also the bottom of the cathode linings 21,21' providing a continuous and optimal electrical contact.
- the cell comprises sidewalls 40, for example made of silicon carbide, which are protected with an aluminium-wetted sidewall lining 41 according to the invention.
- the sidewall lining 41 is completely filled with molten aluminium retained in its pores by capillary effect.
- the sidewall lining 41 extends vertically from the cell bottom 25, 25' to above the surface of the molten electrolyte 5, and completely shields the sidewalls 40 from molten electrolyte 5.
- aluminium-wetted sidewall lining 41 and cathode linings 21,21' are joined through generally wedge-shaped aluminium-filled bodies 51 according to the invention located on the periphery of cell bottom 25,25'.
- FIG 2 illustrates inventive cell components in another cell according to the invention.
- the cell shown in Figure 2 has a horizontal cell bottom 25 which is covered with an aluminium-wetted cathode lining 21 according to the invention of uniform width forming a horizontal drained cathode surface 20.
- the sidewalls 40 of the cell are covered with an aluminium-wetted wedge-shaped sidewall lining 41' that extends from the periphery of the cell bottom 25 to above the surface of the molten electrolyte 5.
- the cell bottom 25 comprises in the middle of the cell, a channel 30 for collecting product aluminium 60 drained from the adjacent aluminium-wettable cathode surfaces 20.
- the aluminium collection channel 30 is preferably coated with a slurry-applied refractory boride layer 35 as described above.
- the slurry-applied layer 35 is wetted by molten aluminium 22 that wets also the bottom of the aluminium-wetted cathode lining 21.
- the cell is thermally well insulated. As shown in Figure 2, the cell is fitted with an insulating cover 45 above the molten electrolyte 5. Further details of suitable covers are disclosed in WO01/31086 (de Nora/Duruz).
- the anodes 10 are preferably made of electrolyte resistant inert metal-based material.
- Suitable metal-based anode materials include iron and nickel based alloys which may be heat-treated in an oxidising atmosphere as disclosed in WO00/06802, WO00/06803 (both in the name of Duruz/de Nora/Crottaz), WO00/06804 (Crottaz'/Duruz), WO01/42535 (Duruz/de Nora), WO01/42534 (de Nora/Duruz) and WO01/42536 (Duruz/Nguyen/de Nora).
- the cell may be operated with an electrolyte 5 at reduced temperature, typically from about 830° to 930°C, preferably from 850° to 910°C.
- an electrolyte 5 at reduced temperature typically from about 830° to 930°C, preferably from 850° to 910°C.
- Operating with an electrolyte at reduced temperature reduces the solubility of oxides, in particular of alumina. Therefore, it is advantageous to enhance alumina dissolution in the electrolyte 5.
- Enhanced alumina dissolution may be achieved by utilising an alumina feed device which sprays and distributes alumina particles over a large area of the surface of the molten electrolyte 5.
- Suitable alumina feed devices are disclosed in greater detail in WO00/63464 (de Nora/Berclaz).
- the cell may comprise means (not shown) to promote circulation of the electrolyte 5 from and to the anode-cathode gap to enhance alumina dissolution in the electrolyte 5 and to maintain in permanence a high concentration of dissolved alumina close to the active surfaces of anodes 10, for example as disclosed in WO00/40781 (de Nora).
- alumina dissolved in the electrolyte is electrolysed to produce oxygen on the anodes 10 and aluminium 60 on the drained cathode surfaces 20.
- the product aluminium 60 drains from the cathode surfaces 20 into the collection channel 30 from where it can be tapped or evacuated into an aluminium reservoir (not shown), for example as disclosed in WO00/63463 (de Nora).
- FIG. 3 where the same reference numerals are used to designate the same elements, illustrates a retrofitted cell utilising aluminium-wetted components according to the invention and conventional consumable carbon anodes 10'.
- the cell bottom 25 is horizontal and protected from wear with an aluminium-wetted cathode lining 21 according to the invention forming a drained cathode surface 20.
- the cell sidewalls 40 are covered with a sidewall lining 41 according to the invention, extending from the cell bottom to above the surface of the molten electrolyte 5.
- the aluminium-wetted sidewall lining 41 and the aluminium-wetted cathode linings 21 are joined through generally wedge-shaped bodies 51 according to the invention.
- the cell bottom 25 is covered with a slurry-applied refractory boride layer 35 wetted by molten aluminium 22 that wets also the bottom of aluminium-wetted cathode lining 21.
- the cell bottom 25 comprises in the middle of the cell, a channel 30 for collecting product aluminium 60 drained from the adjacent aluminium-wettable cathode surfaces 20.
- the cell shown in Figure 3 operates with a frozen electrolyte crust 70 and ledge 71.
- alumina is dissolved into the electrolyte 5 and electrolysed between the carbon anodes 10' and the drained cathode surface 20 to produce CO 2 at the carbon anodes 10' and aluminium which is drained into channel 30.
- a retrofitted cell without an aluminium collection groove may operate with a shallow aluminium cathodic pool with little motion of molten aluminium in the shallow cathodic pool. Consequently, the inter-electrode distance may also be reduced which leads to a reduction of the cell voltage and energy savings. Furthermore, compared to conventional deep pool cells, a smaller amount of molten aluminium is needed to operate the cell which substantially reduces the costs involved with immobilising large aluminium stocks in aluminium production plants.
- aluminium-wetted cathode linings can also be used in deep pool cells operating with a frozen electrolyte ledge and/or an electrolyte crust above the molten electrolyte.
- one or more large aluminium-wetted conductive plates according to the invention made from a low density openly porous or reticulated ceramic structure may be put into the aluminium pool so that the plates float at the surface of the aluminium pool to restrain aluminium motion and stabilise the aluminium pool.
- stabiliser plates in a deep aluminium pool permits a reduction of the inter-electrode distance.
- An openly porous alumina structure (10 pores per inch which is equivalent to about 4 pores per centimetre) was rendered aluminium-wettable by coating it with two slurry-applied layers of different composition.
- the first slurry of the first layer was made of 60 weight% particulate needle-shaped surface-oxidised TiB 2 (-325 mesh) having a TiO 2 surface oxide film, 3.3 weight% aluminium-wetting agent in the form of particulate Fe 2 O 3 (-325 mesh) and 3.3 weight% TiO 2 powder (-325 mesh) in 33 weight% colloidal Al 2 O 3 (NYACOL® Al-20, a milky liquid with a colloidal particle size of about 40 to 60 nanometer).
- the colloidal alumina reacts with a TiO 2 surface oxide and the TiO 2 powder to form a mixed oxide matrix of Al 2 O 3 and TiO 2 throughout the coating, this matrix containing and bonding the TiB 2 particles and the Fe 2 O 3 particles.
- the second slurry was made of 33 weight% of partly oxidised copper particles, 37 weight% of a first grade of colloidal alumina (NYACOL® Al-20) and 30 weight% of a second grade of colloidal alumina (CONDEA® 10/2 Sol, a clear, opalescent liquid with a colloidal particle size of about 10 to 30 nanometer).
- An aluminium-wettable coating was applied onto the porous alumina structure by dipping this structure into the first slurry followed by drying for 4 hours at 40°C and dipping it into the second slurry followed by drying for 15 hours are 40°C.
- the coated alumina structure was then heat treated for 3 hours in air at 700°C to consolidate the coating.
- the resulting structure is aluminium-wettable and is suitable to be wetted by aluminium before use or it can be wetted in-situ when used as a cathode.
- the aluminium-wettable porous structure was wetted with aluminium by dipping it in molten aluminium at 850°C. After 20 hours the wetted porous structure was extracted from the molten aluminium and allowed to cool down to room temperature.
- the electrical resistivity of the aluminium-wetted structure was of the order of the resistivity of metal aluminium (2.65 ⁇ .cm), whereas before wetting the structure had a resistivity of 35 to 45 k ⁇ .cm.
- Such a wetted alumina structure can be used for various applications in an aluminium electrowinning cell, in particular as a cathode or cathode lining, a cell sidewall or a sidewall lining, or as a non current carrying component of the cell bottom which is exposed to molten aluminium and/or electrolyte.
- An aluminium-wettable ceramic structure was made of a mixture of material inert and resistant to molten aluminium, i.e. alumina and titania, and aluminium-wettable material, i.e. copper oxide.
- the ceramic structure was prepared by coating a polyurethane foam with a slurry of ceramic particles followed by a heat treatment.
- the slurry of ceramic material consisted of a suspension of 40 g particulate Al 2 O 3 with an. average particle size of 10 to 20 micron, 2.5 g of particulate CuO with a particle size of less than about 45 micron, 2.5 g of particulate TiO 2 with a particle size of less than about 45 micron in a colloidal alumina carrier consisting of 93 g deionised water and 6.6 g colloidal alumina particles with a colloidal particle size of about 10 to 30 nanometer.
- a polyurethane foam having 10 to 20 pores per inch (equivalent to about 4 to 8 pores per centimetre) was dipped into the slurry and dried in air at 40° to 50°C for 20 to 30 minutes. The dipping was repeated three times.
- the foam was dried in air at 50°C for 4 to 5 hours.
- the foam contained about 0.3 to 0.5 g/cm 3 of the dried slurry.
- the drying was followed by a heat treatment at about 850° to 1000°C in air for 4 to 5 hours to eliminate the polyurethane foam and consolidate the ceramic material formed from the slurry into a self-sustaining foam.
- This heat treatment was followed by an aluminisation treatment by immersion in molten aluminium for 2 hours in molten aluminium at 850°C.
- the aluminised foam was extracted from the molten aluminium, allowed to cool to room temperature and cut perpendicular to a surface.
- the heat treatment step and the aluminisation step are carried out simultaneously as a single step.
- the copper oxide of the ceramic structure is replaced partly or completely with iron oxide and/or nickel oxide.
- An aluminium-wettable openly porous ceramic structure as in Example 1 was tested as cathodic material for aluminium production.
- the aluminium-wettable ceramic structure was placed on the bottom of a graphite receptacle having an inner diameter of 85 mm.
- the structure was covered with 120 g aluminium.
- the receptacle and its content was heated at a rate of 120°C/hour.
- the aluminium had formed an aluminium pool on which the ceramic structure was floating.
- the temperature was further increased to about 850°C and then maintained for 4 hours so that the molten aluminium completely aluminised and wet the ceramic structure.
- an amount of 1.5 kg electrolytic molten bath consisting of 68 weight% cryolite, 28 weight% aluminium fluoride and 4 weight% dissolved alumina was poured into the receptacle on top of the aluminium pool and aluminium-wetted ceramic structure.
- a carbon anode was dipped into the electrolyte to face the floating ceramic structure which formed both an aluminium pool stabiliser and a cathode surface.
- An electrolysis current was passed between the anode and the graphite receptacle at a current density of about 0.8 A/cm 2 at the anode.
- a constant cell voltage of about 4 to 4.2 volt was measured throughout electrolysis.
- the ceramic structure was allowed to cool down to room temperature and cut perpendicular to one of its surfaces. Examination of the ceramic structure showed that it was still completely wetted by and filled with molten aluminium. The ceramic structure itself had remained unchanged demonstrating its stability and suitability as cathode material.
- An openly porous silicon carbide structure (30 pores per inch which is equivalent to about 12 pores per centimetre) was rendered aluminium-wettable by coating it with a slurry-applied layer.
- the slurry consisted of 75 g surface oxidised iron particles (-325 mesh), 75 g Silica sol Nyacol 830 (a milky aqueous liquid containing 32 weight% colloidal silicon hydroxide that is converted into silica upon heat treatment) and 0.35 g of an aqueous solution containing 15% PVA (polyvinyl alcohol) that was used to adjust the. viscosity of the slurry.
- PVA polyvinyl alcohol
- the openly porous structure was dipped onto the slurry and then dried for 30 min. at 60°C.
- the impregnated porous structure contained 0.278 g/cm 3 of dried slurry including 0.214 g/cm 3 surface oxidised iron particles.
- the resulting structure was aluminium-wettable and suitable to be wetted by aluminium before use or in-situ when used for example as a cathode.
- the aluminium-wettable porous structure was wetted with aluminium by dipping it in molten aluminium at 850°C. After 15 hours the wetted porous structure was extracted from the molten aluminium and allowed to cool down to room temperature.
- the aluminium-wetted porous structure showed that it was filled with aluminium retained in the pores by the wettability of the structure and the capillary effect, and covered over the outer surface with aluminium.
- the pores had an aluminium filling ratio that was greater than 90 vol%.
- the aluminium-wetted porous structure can be used as cathodic material like in Example 3.
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Abstract
Description
Claims (34)
- An aluminium-wettable component of a cell for the electrowinning of aluminium from alumina dissolved in a fluoride-based molten electrolyte, said component comprising an openly porous or reticulated ceramic structure whose surface during use is exposed to and wetted by molten aluminium, the structure being made of:a ceramic material inert and resistant to molten aluminium, in particular a material comprising at least one oxide, carbide, nitride or boride selected from: oxides of aluminium, zirconium, tantalum, titanium, silicon, niobium, magnesium and calcium and mixtures thereof, as a simple oxide and/or in a mixed oxide; and aluminium nitride, AlON, SiAlON, boron nitride, silicon nitride, silicon carbide, aluminium borides, alkali earth metal zirconates and aluminates and mixtures thereof; andan aluminium-wettable material that comprises metal oxide and/or partly oxidised metal which is/are reactable with molten aluminium to form on the openly porous or reticulated ceramic structure a surface layer containing alumina, aluminium and metal derived from said metal oxide and/or partly oxidised metal, the metal of said metal oxide and/or partly oxidised metal selected from manganese, iron, cobalt, nickel, copper and zinc and combinations thereof.
- The component of claim 1, wherein the openly porous or reticulated ceramic structure comprises a coating of the aluminium-wettable material on the inert and resistant ceramic material.
- The component of claim 2, wherein the aluminium-wettable coating is a slurry-applied coating comprising particles of said reactable metal oxide and/or partly oxidised metal in a dried colloidal carrier selected from alumina, ceria, lithia, magnesia, silica, thoria, yttria, zirconia, titanium oxide and zinc oxide, and mixtures and precursors thereof.
- The component of claim 3, wherein the slurry-applied aluminium-wettable coating further comprises particles of at least one compound selected from metal borides, carbides and nitrides.
- The component of claim 4, wherein the slurry-applied aluminium-wettable coating comprises the particles of said reactable metal oxide and/or partly oxidised metal and particles of titanium diboride in dried colloidal alumina.
- The component of claim 4 or 5, wherein particles of a metal boride, carbide or nitride are covered with mixed oxides of metal derived from the dried colloidal carrier and metal derived from the metal boride, carbide or nitride.
- The component of claim 6, wherein the slurry-applied aluminium-wettable coating is obtainable from a slurry that comprises metal oxide particles that combine upon heat treatment with a metal oxide derived from the dried colloidal carrier to form mixed oxides which are miscible with said mixed oxides covering the particles of metal boride, carbide or nitride.
- The component of claim 1, wherein the openly porous ceramic structure is made of a composition which consists of a mixture of the inert and resistant ceramic material and the aluminium-wettable ceramic material.
- The component of any preceding claim, wherein the openly porous ceramic structure is formed on a reinforcing metal skeleton.
- The component of any preceding claim, which comprises an internal insert acting as ballast.
- The component of any preceding claim, which is a cathode or a cathode lining.
- The component of any one of claims 1 to 10, which is an aluminium pool stabiliser in the form of a plate.
- The component of any one of claims 1 to 10, which is a skeleton of a cell sidewall or a sidewall lining, which skeletqn can be filled with molten aluminium to form an aluminium-infiltrated cell sidewall or sidewall lining.
- The component of any one of claims 1 to 10, which is a skeleton of a wedge-shaped connecting body for joining the surface of a cell bottom to an adjacent sidewall, which skeleton can be filled with molten aluminium to form an aluminium-infiltrated connecting body.
- An aluminium-wetted component of a cell for the electrowinning of aluminium, said aluminium-wetted component comprising an openly porous or reticulated ceramic structure which has a surface layer containing alumina, aluminium and another metal obtainable by exposing an aluminium-wettable component according to any preceding claim to molten aluminium.
- The aluminium-wetted component of claim 15, which is filled and covered with aluminium that shields the openly porous or reticulated ceramic structure from exposure to molten electrolyte and/or corrosive gases during use.
- The aluminium-wetted component of claim 15 or 16, which is a cathode or a cathode lining.
- The aluminium-wetted component of claims 15 to 16, which is an aluminium pool stabiliser in the form of a plate.
- The aluminium-wetted component of claim 16, which is a cell sidewall or a sidewall lining.
- The aluminium-wetted component of claim 16, which is a wedge-shaped body for joining the surface of a cell bottom to an adjacent sidewall.
- A cell for the electrowinning of aluminium from alumina dissolved in a fluoride-based electrolyte, comprising at least one aluminium-wettable component as defined in any one of claims 1 to 14 and/or at least one aluminium-wetted component as defined in any one of claims 15 to 20.
- The cell of claim 21, which comprises a cathode or a cathode lining as defined in claim 11 or 18.
- The cell of claim 22, which comprises a cathode body having a surface lined with a plate-like or wedge-like cathode lining.
- The cell of claim 23, wherein the cathode body is joined to the cathode lining through a bonding layer.
- The cell of claim 24, wherein the lined cathode surface is part of a horizontal or inclined cathode bottom.
- The cell of claim 25, wherein the cathode bottom is horizontal and lined with a wedge-like cathode lining forming an aluminium-wettable drained sloping cathode surface thereon.
- The cell of claim 22, 23 or 24, wherein the cathode or cathode lining is located above a cell bottom that is arranged to collect molten aluminium produced on and drained from the cathode or cathode lining.
- The cell of any one of claims 22 to 27, comprising a cathode or cathode lining as defined in claim 9 which is top coated with an aluminium-wettable start-up layer.
- The cell of claim 21 or 22, comprising one or more pool stabilisers as defined in claims 12 or 19 floating on an aluminium pool contained in the cell.
- The cell of any one of claims 21 to 29, which comprises a cell sidewall or a sidewall lining as defined in claim 19.
- The cell of claim 30, comprising a sidewall lining as defined in claim 19 that covers a sidewall made of carbon-containing material.
- The cell of any one of claims 21 to 31, comprising at least one wedge-shaped connecting body as defined in claim 20 joining the cell bottom to an adjacent sidewall.
- A composite openly porous or reticulated ceramic structure whose surface is wettable by molten aluminium, the structure being made of:a ceramic material inert and resistant to molten aluminium, in particular a material comprising at least one oxide, carbide, nitride or boride selected from: oxides of aluminium, zirconium, tantalum, titanium, silicon, niobium, magnesium and calcium and mixtures thereof, as a simple oxide and/or in a mixed oxide; and aluminium nitride, AlON, SiAlON, boron nitride, silicon nitride, silicon carbide, aluminium borides, alkali earth metal zirconates and aluminates and mixtures thereof; andan aluminium-wettable material that comprises metal oxide and/or partly oxidised metal which is/are reactable with molten aluminium to form on the openly porous or reticulated ceramic structure a surface layer containing alumina, aluminium and metal derived from said metal oxide and/or partly oxidised metal, the metal of said metal oxide and/or partly oxidised metal selected from manganese, iron, cobalt, nickel, copper and zinc and combinations thereof.
- A composite ceramic-metal material comprising an openly porous or reticulated ceramic structure which has a surface layer containing alumina, aluminium and another metal, said composite ceramic-metal material being obtainable by exposing to molten aluminium a composite openly porous or reticulated ceramic structure as defined in claim 33.
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PCT/IB2002/000668 WO2002070783A1 (en) | 2001-03-07 | 2002-03-04 | Aluminium-wettable porous ceramic material |
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CN103233245B (en) * | 2013-05-23 | 2015-04-29 | 黄河鑫业有限公司 | Method for monitoring and accurately judging damages of online electrolytic cell cathode lining |
US10673066B2 (en) * | 2017-10-06 | 2020-06-02 | Jonathan Jan | Reticulated electrode for lead-acid battery and fabrication method thereof |
WO2019200470A1 (en) * | 2018-04-16 | 2019-10-24 | Laboratoire Cir Inc. | Material components protection against the corrosive action cryolite melts in aluminium reduction cells |
US20240068073A1 (en) * | 2022-08-31 | 2024-02-29 | Ii-Vi Delaware, Inc. | Reinforced metal matrix composites and methods of making the same |
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US4600481A (en) * | 1982-12-30 | 1986-07-15 | Eltech Systems Corporation | Aluminum production cell components |
US4834353A (en) * | 1987-10-19 | 1989-05-30 | Anwar Chitayat | Linear motor with magnetic bearing preload |
US4985651A (en) * | 1987-10-19 | 1991-01-15 | Anwar Chitayat | Linear motor with magnetic bearing preload |
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2002
- 2002-03-04 WO PCT/IB2002/000668 patent/WO2002070783A1/en not_active Application Discontinuation
- 2002-03-04 CA CA002438526A patent/CA2438526A1/en not_active Abandoned
- 2002-03-04 US US10/469,453 patent/US20040149569A1/en not_active Abandoned
- 2002-03-04 AT AT02702625T patent/ATE284983T1/en not_active IP Right Cessation
- 2002-03-04 ES ES02702625T patent/ES2230467T3/en not_active Expired - Lifetime
- 2002-03-04 NZ NZ527306A patent/NZ527306A/en unknown
- 2002-03-04 DE DE60202265T patent/DE60202265T2/en not_active Expired - Fee Related
- 2002-03-04 EP EP02702625A patent/EP1366214B1/en not_active Expired - Lifetime
- 2002-03-04 RU RU2003129656/02A patent/RU2281987C2/en not_active IP Right Cessation
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013075396A1 (en) * | 2011-11-21 | 2013-05-30 | 中铝国际工程股份有限公司 | Lateral composite block for liner in heat-insulating aluminum electrolysis cell |
Also Published As
Publication number | Publication date |
---|---|
RU2003129656A (en) | 2005-02-10 |
DE60202265D1 (en) | 2005-01-20 |
NZ527306A (en) | 2006-03-31 |
DE60202265T2 (en) | 2005-05-25 |
RU2281987C2 (en) | 2006-08-20 |
ES2230467T3 (en) | 2005-05-01 |
CA2438526A1 (en) | 2002-09-12 |
US20040149569A1 (en) | 2004-08-05 |
EP1366214A1 (en) | 2003-12-03 |
WO2002070783A1 (en) | 2002-09-12 |
ATE284983T1 (en) | 2005-01-15 |
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