WO2023172717A1 - Systems and methods for purifying aluminum - Google Patents
Systems and methods for purifying aluminum Download PDFInfo
- Publication number
- WO2023172717A1 WO2023172717A1 PCT/US2023/014946 US2023014946W WO2023172717A1 WO 2023172717 A1 WO2023172717 A1 WO 2023172717A1 US 2023014946 W US2023014946 W US 2023014946W WO 2023172717 A1 WO2023172717 A1 WO 2023172717A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- aluminum
- anode
- cathode
- impure
- anode structure
- Prior art date
Links
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 508
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 498
- 238000000034 method Methods 0.000 title claims abstract description 75
- 239000012768 molten material Substances 0.000 claims abstract description 161
- 238000000746 purification Methods 0.000 claims abstract description 119
- 239000011244 liquid electrolyte Substances 0.000 claims abstract description 93
- 239000003792 electrolyte Substances 0.000 claims abstract description 66
- 238000004891 communication Methods 0.000 claims abstract description 32
- 239000012530 fluid Substances 0.000 claims abstract description 31
- 239000000463 material Substances 0.000 claims description 62
- QYEXBYZXHDUPRC-UHFFFAOYSA-N B#[Ti]#B Chemical compound B#[Ti]#B QYEXBYZXHDUPRC-UHFFFAOYSA-N 0.000 claims description 22
- 229910033181 TiB2 Inorganic materials 0.000 claims description 22
- 239000011148 porous material Substances 0.000 claims description 21
- 238000005192 partition Methods 0.000 claims description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 16
- 229910002804 graphite Inorganic materials 0.000 claims description 15
- 239000010439 graphite Substances 0.000 claims description 15
- -1 aluminum ions Chemical class 0.000 claims description 11
- 239000010949 copper Substances 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 4
- 238000005265 energy consumption Methods 0.000 claims description 4
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 3
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 3
- 239000004917 carbon fiber Substances 0.000 claims description 3
- 239000003575 carbonaceous material Substances 0.000 claims description 3
- 239000004744 fabric Substances 0.000 claims description 3
- 239000006260 foam Substances 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 3
- 210000004027 cell Anatomy 0.000 description 110
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 8
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 6
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- 239000000956 alloy Substances 0.000 description 4
- 230000000737 periodic effect Effects 0.000 description 4
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 239000010409 thin film Substances 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 229910000881 Cu alloy Chemical group 0.000 description 3
- 239000010405 anode material Substances 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000012811 non-conductive material Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 210000002421 cell wall Anatomy 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 229910001512 metal fluoride Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 235000013024 sodium fluoride Nutrition 0.000 description 2
- 239000011775 sodium fluoride Substances 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000037361 pathway Effects 0.000 description 1
- 239000011698 potassium fluoride Substances 0.000 description 1
- 235000003270 potassium fluoride Nutrition 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
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
- C25C3/24—Refining
-
- 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
- C25C3/12—Anodes
-
- 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
- C25C3/18—Electrolytes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/005—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells of cells for the electrolysis of melts
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
- C25C7/025—Electrodes; Connections thereof used in cells for the electrolysis of melts
Definitions
- the Hoopes cell is a horizontal electrorefining cell consisting of molten electrolyte which separates two molten electrodes: impure aluminum alloyed with copper as the anode and pure aluminum acting as the cathode.
- the impure aluminum is alloyed with copper to increase its density so that the impure aluminum and copper alloy forms the anode layer at the bottom of the cell.
- an electrolyte with a density greater than the density of pure aluminum is required for Hoopes cell configurations so that the pure aluminum can form the topmost cathode layer, floating on the electrolyte, of the three-layer cell.
- Hoopes-cell based electrorefining processes the aluminum in the anode layer at the bottom of the cell can become depleted over time, and as such, Hoopes-cell based systems can require periodic exchanges of the aluminum-depleted anode layer with new impure aluminum and copper alloy material, which can reduce system efficiency. Therefore, there is a need in the art for electrorefining systems and methods of aluminum purification that are not as energy intensive as the systems and methods associated with the Hoopes cell. Additionally, there is a need for electrorefining systems capable of continuous operation.
- the disclosed subject matter includes systems and methods of aluminum purification.
- Aluminum purification systems in accordance with the disclosed subject matter include a cell defining a chamber having an upper portion and a lower portion. The lower portion includes a cathode molten material collection area defined therein.
- Systems in accordance with the disclosed subject matter further include an anode structure disposed in the upper portion of the chamber vertically aligned above the lower portion and a cathode structure disposed in the upper portion of the chamber vertically aligned above the cathode molten material collection area.
- a liquid electrolyte is included within the chamber in fluid communication with the anode structure and the cathode structure.
- the anode structure is configured to receive impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density. Further, the cathode structure is configured to capture purified aluminum in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum through the liquid electrolyte, the cathode structure further defining a cathode flow path along which purified aluminum can flow from the upper portion to the cathode molten material collection area.
- An interface can be defined between the liquid electrolyte and molten aluminum contained in the cathode molten material collection area, and the interface can be below the cathode structure.
- the liquid electrolyte can flow freely between the anode structure and the cathode structure.
- the anode structure can include a first anode structure portion and a second anode structure portion and an anode reservoir therebetween, and the anode structure can be configured to receive impure aluminum in the anode reservoir.
- a first side of the second anode structure portion can be in fluid communication with the impure aluminum and a second side of the second anode structure portion can be in fluid communication with the liquid electrolyte.
- the second anode structure can include pores.
- the pores in the second anode structure can be sized to prevent impure aluminum from flowing through the pores and to allow aluminum ions to pass through the pores.
- the second anode structure portion can be configured to become impregnated with impure aluminum.
- the second anode structure portion can be configured to slowly allow the impure aluminum to transit through the anode face.
- the lower portion can include an anode molten material collection area.
- the anode structure can be vertically aligned above the anode molten material collection area. Additionally or alternatively, the cathode molten material collection area can be separated from the anode molten material collection area by a partition disposed therebetween.
- An interface can be defined between the liquid electrolyte and molten aluminum contained in each of the anode molten material collection area and the cathode molten material collection area, and the partition can extend within the chamber from a bottom of the cell to a height above the interface. Additionally or alternatively, the liquid electrolyte can have an upper surface and the partition can not contact the upper surface of the liquid electrolyte.
- the anode structure can define an anode flow path along which impure aluminum in a molten state can flow from the upper portion to the anode molten material collection area.
- the anode flow path can extend from the anode reservoir through the second anode structure portion to the anode molten material collection area.
- the anode structure can include an aluminum- wettable material.
- the anode flow path can include a layer of molten impure aluminum along the surface of the anode structure.
- the aluminum-wettable material can include titanium diboride (TiB2) at least on a surface of the anode.
- TiB2 can be an electroplated layer on the surface of the anode structure.
- the anode structure can include graphite and the TiB2 layer can be disposed thereon.
- the cathode structure can include an aluminum-wettable material. Additionally or alternatively, the cathode flow path can include a layer of molten purified aluminum along the surface of the cathode structure.
- the aluminum-wettable material can include TiB2 at least on a surface of the cathode structure.
- the TiB2 can be an electroplated layer on the surface of the cathode structure.
- the cathode structure can include graphite and the TiB2 layer can be disposed thereon. Additionally or alternatively, the cathode structure can include tungsten.
- the anode structure and the cathode structure can both include an aluminum wettable material.
- the anode structure and cathode structure can both include the same wettable material.
- the liquid electrolyte can include lithium fluoride (LiF) and aluminum fluoride (A1F3).
- the liquid electrolyte can further include sodium fluoride (NaF), potassium fluoride (KF), calcium fluoride (CaF2), and other metal fluorides which will obtain an equilibrium with the refining process.
- the liquid electrolyte can have a density of less than about 2.7 g/cm 3 .
- the distance between the anode structure and cathode structure can be between about 2mm and about 5 cm.
- the disclosed subject matter further includes methods of aluminum purification.
- Methods in accordance with the disclosed subject matter include operating an aluminum purification system having any of the features described above.
- Methods in accordance with the disclosed subject matter further include introducing impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density into the chamber to be received by the anode structure.
- the anode structure can define an anode flow path along which the impure aluminum can flow from the upper portion to the anode molten material collection area.
- Methods in accordance with the disclosed subject matter further include capturing purified aluminum in a molten state having a purified aluminum density greater than the electrolyte density at the cathode structure from the impure aluminum through the liquid electrolyte, the cathode structure defining a cathode flow path along which the purified aluminum can flow from the upper portion to the cathode molten material collection area and collecting in the second molten collection area purified aluminum released from the cathode structure.
- FIG. l is a schematic side cross-sectional view of an aluminum purification system in accordance with the disclosed subject matter.
- FIG. 2 is an exemplary method of aluminum purification in accordance with the disclosed subject matter.
- FIG. 3 is a schematic side cross-sectional view of an aluminum purification system in accordance with the disclosed subject matter.
- FIG. 3 A is a schematic side cross-sectional view of an aluminum purification system in accordance with the disclosed subject matter.
- FIG. 4 is a schematic partial side cross-sectional view of an aluminum purification system in accordance with the disclosed subject matter.
- FIG. 5 is a schematic partial side cross-sectional view of an aluminum purification system in accordance with the disclosed subject matter.
- Aluminum purification systems in accordance with the disclosed subject matter generally include a cell defining a chamber.
- the chamber includes an upper portion and a lower portion.
- the lower portion includes a cathode molten material collection area defined therein.
- Systems in accordance with the disclosed subject matter further include an anode structure and a cathode structure disposed in the upper portion of the chamber.
- the anode structure is vertically aligned above the lower portion.
- the cathode structure is vertically aligned above the cathode molten material collection area.
- Systems in accordance with the disclosed subject matter further include a liquid electrolyte within the chamber and in fluid communication with the anode structure and the cathode structure.
- the liquid electrolyte has an electrolyte density.
- the anode structure is configured to receive impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density.
- the cathode structure is configured to capture purified aluminum in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum through the liquid electrolyte.
- the cathode structure further defines a cathode flow path along which purified aluminum can flow from the upper portion to the cathode molten material collection area.
- the disclosed subject matter further includes methods of aluminum purification.
- Methods of aluminum purification in accordance with the disclosed subject matter generally include operating a purification system.
- the system includes a cell defining a chamber.
- the chamber includes an upper portion and a lower portion.
- the lower portion includes a cathode molten material collection area defined therein.
- the system further includes an anode structure and a cathode structure disposed in the upper portion of the chamber.
- the anode structure is vertically aligned above the lower portion.
- the cathode structure is vertically aligned above the cathode molten material collection area.
- a liquid electrolyte is within the chamber and is in fluid communication with the anode structure and the cathode structure.
- Methods of aluminum purification in accordance with the disclosed subject matter further include introducing impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density into the chamber to be received by the anode structure.
- Methods in accordance with the disclosed subject matter further include capturing purified aluminum in a molten state having a purified aluminum density greater than the electrolyte density at the cathode structure from the impure aluminum through the liquid electrolyte, the cathode structure defining a cathode flow path along which the purified aluminum can flow from the upper portion to the cathode molten material collection area, and collecting in the cathode molten material collection area purified aluminum released from the cathode structure.
- FIGS. 1 and 2 For purpose of explanation and illustration, and not limitation, exemplary systems and methods of aluminum purification in accordance with the disclosed subject matter are shown in FIGS. 1 and 2.
- the term “or” is an inclusive “or” operator and is equivalent to the term “and/or,” unless the context clearly dictates otherwise.
- the term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise.
- the meaning of “a,” “an,” and “the” include plural references.
- the meaning of “in” includes “in” and “on.”
- purified aluminum is a broad and relative term and includes material having a higher wt. % aluminum than impure aluminum material.
- the purification system 100 comprises a cell 101 defining a chamber 102.
- the chamber 102 has an upper portion 103 and a lower portion 104.
- the lower portion 104 includes a cathode molten material collection area 106.
- the lower portion 104 can further include an anode molten material collection area 105.
- the anode molten material collection area 105 can be separated from the cathode molten material collection area 106 by a partition 107 disposed therebetween.
- the anode molten material collection area 105 and cathode molten material collection area 106 can define respective reservoirs separated by the partition 107, and each can be configured to receive molten material.
- the partition 107 can extend along a centerline of the system 100 and the anode molten material collection area 105 and cathode molten material collection area 106 can define respective reservoirs having approximately the same volume.
- the anode molten material collection area 105 and cathode molten material collection area can have different dimensions and volumes.
- an anode structure 108 is disposed in the upper portion of the chamber such that it is vertically aligned above the lower portion 104.
- the anode structure 108 can be vertically aligned above the anode molten material collection area 105.
- the anode structure 108 is configured to receive impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density.
- the anode structure 108 can define an anode flow path along which impure aluminum can flow from the upper portion 103 to the anode molten material collection area 105, as described further herein.
- the anode structure 108 can include an aluminum-wettable material.
- Suitable aluminum-wettable materials for the anode structure can include, for example, materials having a contact angle with molten aluminum of not greater than 90 degrees measured in the presence of fluoride electrolytes, although aluminum-wettable materials having a contact angle greater than 90 degrees can also be used.
- the aluminum-wettable material can include titanium diboride (TiB2).
- TiB2 titanium diboride
- the anode structure can be made entirely of the aluminum-wettable material.
- a layer of aluminum-wettable material can be provided on the surface of the anode structure.
- the anode structure can include a graphite body and titanium diboride can be electroplated onto the graphite to form a layer of titanium diboride on the surface of the anode structure. Additionally or alternatively, titanium diboride can be thermal sprayed onto the anode structure.
- the system 100 includes one anode structure 108; however, additional anode structures can be included.
- the number of anode structures can be selected based on the desired performance properties of the purification system.
- Anode structures can be used in parallel or in series.
- molten aluminum can be collected in the cathode molten material collection area 106 of system 100 and transferred to an anode structure of another cell for further purification.
- impure aluminum can be collected in the anode molten material collection area 105 and transferred to an anode structure of another cell for further purification.
- the molten aluminum can be processed through any desirable number of cells in series until the molten aluminum reaches a desired level of purity, as described further herein. Additionally or alternatively, multiple anode structures can be included in a single cell.
- a cathode structure 109 is disposed in the upper portion of the chamber and vertically aligned above the cathode molten material collection area 106.
- the cathode structure 109 defines a cathode flow path along which purified aluminum can flow from the upper portion to the cathode molten material collection area 106, as described further herein.
- the system 100 includes one cathode structure 109; however, additional cathode structures can be included.
- the number of cathode structures can be selected based on the desired performance properties of the purification system. For example, cathode structures can be placed in series or in parallel, as described above.
- the cathode structure 109 can be disposed in the upper portion 103 of the chamber opposite to the anode structure 108 and spaced from the anode structure by an anode structure-cathode structure distance.
- the anode structure-cathode structure distance can be selected according to the desired properties of the system.
- the anode structure-cathode structure distance can be between 2mm and 5 cm.
- the anode structure-cathode structure distance can be approximately 4 cm.
- the cathode structure can include an aluminum- wettable material.
- Suitable aluminum-wettable materials for the cathode structure can include, for example, materials having a contact angle with molten aluminum of not greater than 90 degrees, although aluminum-wettable materials having a contact angle greater than 90 degrees can also be used.
- both the anode structure and cathode structure can include a aluminum-wettable materials.
- the aluminum-wettable material for both the anode structure and the cathode structure can be titanium diboride (TiB2). Additionally or alternatively, the anode structure and cathode structure can have different aluminum-wettable materials.
- the cathode structure can be made entirely of the aluminum-wettable material.
- a layer of aluminum-wettable material can be provided on the surface of the cathode structure.
- the cathode structure can include a graphite body and titanium diboride can be electroplated onto the graphite to form a layer of titanium diboride on the surface of the cathode structure.
- Both the anode structure 108 and cathode structure 109 are in fluid communication with an liquid electrolyte 110 within the chamber 102.
- the liquid electrolyte can be disposed in the chamber 102 between the anode structure 108 and the cathode structure 109 and above the anode molten material collection area 105 and cathode molten material collection area 106.
- the electrolyte 110 can flow freely between the anode structure 108 and the cathode structure 109.
- the liquid electrolyte 110 has an electrolyte density.
- impure aluminum added to the system 100 has an impure aluminum density greater than the electrolyte density.
- purified aluminum captured at the cathode structure has a purified aluminum density greater than the electrolyte density.
- the liquid electrolyte has an upper surface 111 in the upper portion of the chamber, wherein the partition 107 is configured so as not to contact the upper surface.
- an interface 117 can be defined between the liquid electrolyte 110 and molten aluminum contained in the cathode molten material collection area 106.
- the interface 117 can be below the cathode structure 109.
- the liquid electrolyte can be any suitable medium in which the flow of electrical current is carried out by the movement of ions/ionic species.
- the liquid electrolyte can include lithium fluoride, aluminum fluoride, and/or sodium fluoride.
- the liquid electrolyte 110 can include lithium fluoride, aluminum fluoride, sodium fluoride, potassium fluoride, calcium fluoride, and other base metal fluorides, or combinations thereof, which will obtain an equilibrium with the refining process.
- the liquid electrolyte can include sodium fluoride (NaF) and aluminum fluoride (A1F3).
- the liquid electrolyte can include lithium fluoride (LiF) and potassium fluoride (KF).
- LiF lithium fluoride
- KF potassium fluoride
- the liquid electrolyte 110 can be selected so as to provide the desired electrolyte density and related performance characteristics.
- the liquid electrolyte can have a density of less than about 2.7 g/cm 3 .
- the anode structure 108 can define an anode flow path along which impure aluminum 112 in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion 103 to the anode molten material collection area 105.
- the impure aluminum 112 can be heated to a molten state using any suitable means.
- waste heat such as from another manufacturing process, can be used to heat the impure aluminum.
- the anode structure 108 can include a wettable material as described above, and the anode flow path can include a thin layer of molten impure aluminum along the surface of the anode structure 108.
- impure aluminum 112 can be introduced in the chamber 102 at an upper portion of the anode structure 108, and the impure aluminum 112 can flow down a surface of the anode structure 108 opposite to the cathode structure 109.
- a thin film of impure aluminum 112 can be created along the surface of the anode structure 108 as the impure aluminum flows along the surface of the anode structure 108 from the upper portion to the lower portion.
- the anode structure 108 can be comprised of non- conductive materials, and the impure aluminum 112 can form the electrically conductive anode for the system.
- the system 100 can further include one or more leads electrically connected to the conductive anode, as is known in the art.
- the impure aluminum 112 can drip into the anode molten material collection area 105 when the impure aluminum 112 reaches the lower edge of the anode structure 108. Additionally or alternatively, the anode flow path can extend through the anode structure 108 or a portion thereof, as described further herein.
- the flow of impure aluminum 112 from the upper portion 103 to the anode molten material collection area 105 is related to, among other things, the relative density of the liquid electrolyte 110 and the impure aluminum 112.
- the impure aluminum 112 has a greater density than the electrolyte density and tends to flow down within the cell 101 and the liquid electrolyte 110.
- systems in accordance with the disclosed subject matter can be used to purify impure aluminum that has not been alloyed with copper to increase its density, as is common in other aluminum purification systems, such as the Hoopes cell.
- the anode molten material collection area 105 can include an outlet 114 in fluid communication with the anode molten material collection area 105 for removal of impure aluminum 112 from the anode molten material collection area 105.
- impure aluminum 112 from the anode molten material collection area 105 can be recirculated to the top of the system 100 and the anode 108, for example, to maintain a thin film of impure aluminum 112 on the anode 108.
- the system 100 can include a pump 116 in fluid communication with the outlet 114, and the pump 116 can circulate impure aluminum 112 from the anode molten collection area 105 to the anode structure 108.
- the outlet 114 can be used to bleed impure aluminum 112 from cell 101 and new impure aluminum material can be introduced to the cell. Additionally or alternatively, impure aluminum 112 can be transferred to another cell through the outlet 114.
- the cathode structure 109 is configured to capture purified aluminum 113 in a molten state having an impure aluminum density greater than the electrolyte density from the impure aluminum 112 through the liquid electrolyte 110.
- the cathode structure 109 further defines a cathode flow path along which purified aluminum 113 can flow from the upper portion 103 to the cathode molten material collection area 106.
- the flow of purified aluminum 113 from the upper portion 103 to the cathode molten material collection area 106 is related to, among other things, the relative density of the liquid electrolyte 110 and the purified aluminum 113.
- the purified aluminum 113 has a greater density than the electrolyte density and tends to flow down within the cell 101 and the liquid electrolyte 110.
- systems in accordance with the disclosed subject matter can purify aluminum at higher efficiencies than other systems, such as Hoopes cells, which require liquid electrolyte with a density greater than that of purified aluminum.
- systems in accordance with the disclosed subject matter can be used with electrolytes having higher conductivity and lower density.
- the cathode structure 109 can include a wettable material as described above, and the cathode flow path can include a thin layer of molten purified aluminum 113 along the surface of the cathode structure 109.
- the purified aluminum 113 collected on the cathode structure 109 can flow along the vertically oriented cathode structure 109 and drip into the cathode molten material collection area 106.
- the cathode structure 109 can be comprised of non-conductive material, and the purified aluminum 113 can form the electrically conductive cathode for the system 100.
- the system 100 can further include one or more leads electrically connected to the conductive cathode, as is known in the art.
- a voltage and/or current can be applied across the anode and cathode, and aluminum ions from the thin film of aluminum on the surface of the anode structure 108 can move to the cathode structure through the liquid electrolyte 110.
- the aluminum ions can form a thin film of purified aluminum 113 on the surface of the cathode structure 109.
- the cathode structure 109 can be configured to capture purified aluminum having a higher weight percent (wt. %) aluminum than the impure aluminum introduced to the anode structure.
- impure aluminum having at least 80 wt. % aluminum can be introduced to the anode structure, and the purified aluminum captured at the cathode structure can have at least 99 wt. % aluminum. Additionally or alternatively, the purified aluminum captured at the cathode structure can have at least 99.5 wt. % aluminum. Additionally or alternatively, the purified aluminum captured at the cathode structure can have at least 99.9 wt. % aluminum.
- the system 100 can include an outlet 115 in fluid communication with the cathode molten material collection area 106.
- outlet 115 can be in fluid communication with the cathode molten material collection area 106 for removal of purified aluminum 113 therefrom.
- FIG. 3 depicts another purification system 300 in accordance with the disclosed subject matter.
- the purification system 300 comprises a cell 301 defining a chamber 302.
- the chamber 302 has an upper portion 303 and a lower portion 304.
- the lower portion includes a cathode molten material collection area 306.
- the lower portion 304 can further include an anode molten material collection area 305.
- the anode molten material collection area 305 can be separated from the cathode molten material collection area 306 by a partition 307 disposed therebetween.
- the system further includes an anode structure 308 disposed in the upper portion of the chamber 302 and vertically aligned above the lower portion 304.
- the anode structure can be vertically aligned above the anode molten material collection area 305.
- a cathode structure 309 is disposed in the upper portion of the chamber 302 and vertically aligned above the cathode molten material collection area 306.
- a liquid electrolyte 310 is disposed within the chamber 302 in fluid communication with the anode structure 308 and the cathode structure 309.
- the anode structure 308 is configured to receive impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density.
- the anode structure 308 can include a first anode structure portion 321 and a second anode structure portion 322 and an anode reservoir 323 therebetween.
- the anode structure 308 can receive impure aluminum 312 in the anode reservoir 323.
- a first side of the second anode structure portion 322 can be in fluid communication with the impure aluminum 312 and a second side of the second anode structure portion 322 can be in fluid communication with liquid electrolyte 310.
- the anode structure 308 can define an anode flow path along which impure aluminum 312 in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion 303 to the anode molten material collection area 305.
- the anode flow path can extend from the anode reservoir 323 through the second anode structure portion 322 to the anode molten material collection area 305.
- the second anode structure portion 322 can be porous, and impure aluminum 312 can flow from the anode reservoir 323 through the pores of the second anode structure portion 322 and fall into the anode molten material collection area 305.
- a wall of the cell 301 can define the first anode structure portion 321 and the second anode structure portion 322 can form a barrier to retain the impure aluminum 312 between the first anode structure portion 321 and the second anode structure portion 322.
- systems can incorporate multiple cells, and a wall of the cell can, for example, define a first anode structure portion for a first cell and define a cathode structure for a second, adjacent, cell.
- the second anode structure portion can be positioned relative to the first anode structure portion 321 to achieve the desired thickness and volume of impure aluminum 312 within the anode reservoir 323.
- the anode reservoir 323 can be filed with impure aluminum 312.
- the anode reservoir 323 can be filed with only impure aluminum and have no liquid electrolyte therein.
- the second anode structure portion 322 can comprise any suitable material.
- the second anode structure portion 322 can comprise a porous material.
- the second anode structure portion 322 can include graphite, carbon fiber cloth, porous TiB2 and/or foam.
- the second anode material 322 can include a porous carbon material. Additionally or alternatively, holes or pathways can be defined in the second anode material 322.
- the material of the second anode material 322 can be selected to provide a desired impure aluminum flow rate from the anode reservoir 323 to the anode molten material collection area 305.
- the second anode structure portion 322 can become impregnated with the impure aluminum 312 as the impure aluminum flows through the second anode structure portion 322.
- a voltage and/or current can be applied between the impure aluminum 312 and the cathode, and aluminum ions from the impure aluminum 312 can move to the cathode structure through the liquid electrolyte 110.
- the porosity and/or ease with which impure aluminum 312 can flow through the second anode structure portion 322 can be selected based on desired system performance. For example, more porous materials, and/or materials that allow for greater diffusion of the impure aluminum 312, can be used for the second anode structure portion 322 and can support higher aluminum flow rates, higher current densities, and increased rates of collection of purified aluminum at the cathode structure 309. Additionally or alternatively, less porous materials, and/or materials that allow for less diffusion of the impure aluminum 312, can be used for the second anode structure portion 322 and can support lower aluminum flow rates, lower current densities, and lower rates of collection of purified aluminum at the cathode structure 309.
- the anode structure 308 can include a anode reservoir bottom portion 325.
- the anode reservoir bottom portion 325 can prevent impure aluminum 312 from flowing through the anode reservoir bottom portion 325.
- the anode reservoir bottom portion 325 can comprise a nonporous material.
- the anode reservoir bottom portion can separate and electrically insulate the anode from the anode molten material collection area 305.
- the impure aluminum 312 can be the anode in the system 300.
- the first anode structure portion 321 and second anode structure portion 322 can be comprised of non-conductive materials, or materials with lower conductance than the impure aluminum 312.
- a lead can be used in communication with the impure aluminum 312 to apply a voltage and/or current thereto.
- the liquid electrolyte 310 has an electrolyte density and the impure aluminum 312 has an impure aluminum density greater than the electrolyte density.
- the flow of impure aluminum 112 from the upper portion 303 to the anode molten material collection area 305 is related to, among other things, the relative density of the liquid electrolyte 310 and the impure aluminum 312.
- purified aluminum 313 captured at the cathode structure 309 has a purified aluminum density greater than the electrolyte density.
- the liquid electrolyte 310 can form a layer within the chamber 302 above the molten aluminum contained in the anode molten material collection area 305 and cathode molten material collection area 306, respectively.
- an interface 316 can be defined between the liquid electrolyte 310 and the molten aluminum contained in the anode molten material collection area 305 and cathode molten material collection area 306, respectively.
- the partition 307 can be configured to extend from the bottom of the cell to a height above the interface 316 to maintain separation between the impure aluminum in the anode molten material collection area 305 and the purified aluminum contained in the cathode molten material collection area 306.
- the interface 316 can be below the cathode structure 309.
- the area of the chamber 302 between the anode structure 308 and the cathode structure 309 can be free of barriers or membranes or other structures which could otherwise impede the flow of electrolyte 310 between the anode structure 310, the cathode structure 309. Having a free flow of liquid electrolyte 310 within the chamber 302 and between the anode structure 310 and the cathode structure 309 can be desirable for steady state kinetics of the system 300.
- the cathode structure 309 is configured to capture purified aluminum 313 in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum 312 through the liquid electrolyte 310.
- the cathode structure 309 further defines a cathode flow path along which the purified aluminum 313 can flow from the upper portion 303 to the cathode molten material collection area 306.
- cathode structure 309 is disposed in the upper portion of the chamber 302 and is vertically aligned above the cathode molten material collection area 306.
- the cathode structure 309 is configured to capture purified aluminum 313 in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum through the liquid electrolyte 310.
- the cathode structure 309 can be comprised of any suitable material.
- the material of the cathode structure can include tungsten or graphite. Additionally or alternatively, and as embodied herein, the cathode structure 309 can be comprised of aluminum.
- the cathode structure 309 can have any suitable shape and structure.
- the surface of the cathode structure 309 can include one or more grooves defined therein and purified aluminum 313 can be deposited in the grooves of the cathode structure 309.
- the cathode structure 309 can include grooves defined in the surface of the cathode structure and extending vertically.
- Including grooves or channels in the cathode structure can provide further stability to the layers of aluminum that form on the cathode structure during operation of the system. Additionally or alternatively, including grooves or channels in the anode the cathode structure can reduce the likelihood of aluminum bridging between the anode and cathode. For example and not limitation, including grooves or channels in the cathode structure can reduce the likelihood of aluminum bridging between the anode and cathode when the distance between the anode structure and cathode structure is reduced, as described further herein. As described above, purified aluminum 313 can be collected on the cathode structure 309 and can flow along the vertically oriented cathode structure 309 and drip into the cathode molten material collection area 306.
- FIG. 3A depicts another purification system 300a in accordance with the disclosed subject matter.
- the purification system 300a comprises a cell 301a defining a chamber 302a.
- the chamber 302a has an upper portion 303a and a lower portion 304a.
- the lower portion 304a includes a cathode molten material collection area 306a defined therein.
- the system further includes an anode structure 308a disposed in the upper portion 303 a of the chamber 302a and vertically aligned above the lower portion 304a.
- a cathode structure 309a is disposed in the upper portion 303a of the chamber 302a and vertically aligned above the cathode molten material collection area 306a.
- a liquid electrolyte 310a is disposed within the chamber 302a in fluid communication with the anode structure 308a and the cathode structure 309a.
- the liquid electrolyte 310a has an electrolyte density.
- the anode structure 308a is configured to receive impure aluminum 312a in a molten state having an impure aluminum density greater than the electrolyte density.
- the cathode structure 309a is configured to capture purified aluminum 313a in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum through the liquid electrolyte 310a.
- the cathode structure 309a further defines a cathode flow path along which purified aluminum 313a can flow from the upper portion 303a to the cathode molten material collection area 306a.
- the cathode flow path can include a layer of molten purified aluminum 313a along the surface of the cathode structure 309a.
- the purified aluminum 313a collected on the cathode structure 309a can flow along the vertically oriented cathode structure 309a and drip into the cathode molten material collection area 306a.
- the anode structure 308a can include a first anode structure portion 321a and a second anode structure portion 322a and an anode reservoir 323a therebetween.
- the anode structure 308a can receive impure aluminum 312a in the anode reservoir 323a.
- a first side of the second anode structure portion 322a can be in fluid communication with the impure aluminum 312a and a second side of the second anode structure portion 322a can be in fluid communication with liquid electrolyte 310a.
- the second anode structure portion 322a can be porous.
- the pores in the second anode structure portion 322a can be sized to prevent impure aluminum from flowing through the pores and to allow aluminum ions to pass through the pores.
- a wall of the cell 301a can define the first anode structure portion 321a and the second anode structure portion 322a can form a barrier to retain the impure aluminum 312a between the first anode structure portion 321a and the second anode structure portion 322a.
- systems can incorporate multiple cells, and a wall of the cell can, for example, define a first anode structure portion for a first cell and define a cathode structure for a second, adjacent, cell.
- the second anode structure portion can be positioned relative to the first anode structure portion 321a to achieve the desired thickness and volume of impure aluminum 312a within the anode reservoir 323a.
- the anode reservoir 323a can be filed with impure aluminum 312a.
- the anode reservoir 323a can be filed with only impure aluminum and have no liquid electrolyte therein.
- the second anode structure portion 322a can comprise any suitable material.
- the second anode structure portion 322a can comprise a porous material.
- the anode structure 308a can include an anode reservoir bottom portion 325a.
- the anode reservoir bottom portion 325a can prevent impure aluminum 312a from flowing through the anode reservoir bottom portion 325a.
- the anode reservoir bottom portion 325a can comprise a nonporous material. Additionally or alternatively, and as further embodied herein, the anode reservoir bottom portion 325a can separate and electrically insulate the anode structure 308a from the cathode molten material collection area 306a.
- system 300a can include a pump 316a.
- Pump 316a can be used to remove impure aluminum material 312a from the reservoir 323a.
- transferring impure aluminum 312a from the anode structure 308a can prevent build up and/or concentration of impurities in the impure aluminum 312a received at the anode structure, as described further herein.
- impure aluminum 312a can be transferred from the anode structure 308a to a second cell, the transferred impure aluminum to be received by a second anode structure, as described further herein.
- aluminum purification systems can include more than one cell.
- the purification system 400 comprises a cell defining a first chamber 402a.
- the chamber 402a has an upper portion 403 and a lower portion 404.
- the lower portion 404 includes a cathode molten material collection area 406a.
- the lower portion 404 can further include an anode molten material collection area 405.
- the anode molten material collection area 405 can be separated from the cathode molten material collection area 406a by a partition 407a disposed therebetween.
- the system 400 further includes an anode structure 408 disposed in the upper portion of the chamber 402a and vertically aligned above the lower portion 404.
- the anode structure 408 can be disposed in the upper portion of the chamber 402a and vertically aligned above the anode molten material collection area 405.
- a cathode structure 409a is disposed in the upper portion of the chamber 402a and vertically aligned above the cathode molten material collection area 406a.
- a liquid electrolyte 410 is disposed within the chamber 402a in fluid communication with the anode structure 408 and the cathode structure 409a.
- the cathode structure 409a is configured to capture purified aluminum 413 in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum 412 through the liquid electrolyte 410.
- the cathode structure 409a further defines a cathode flow path along which the purified aluminum 413 can flow from the upper portion 403 to the cathode molten material collection area 406a.
- the anode structure 408 can define an anode flow path along which impure aluminum 412 in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion to the anode molten material collection area 405.
- the system 400 further includes a cell defining a second chamber 402b.
- the chamber 402b has an upper portion 403 and a lower portion 404.
- the lower portion 404 includes a cathode molten material collection area 406b.
- the lower portion 404 can further include an anode molten material collection area 405.
- the anode molten material collection area 405 can be separated from the cathode molten material collection area 406b by a partition 407b disposed therebetween.
- the system 400 further includes an anode structure 408 disposed in the upper portion of the chamber 402b and vertically aligned above the lower portion
- the anode structure 408 can be disposed in the upper portion of the chamber 402b and vertically aligned above the anode molten material collection area
- a cathode structure 409b is disposed in the upper portion of the chamber 402b and vertically aligned above the cathode molten material collection area 406b.
- a liquid electrolyte 410 is disposed within the chamber 402b in fluid communication with the anode structure 408 and the cathode structure 409b.
- the cathode structure 409b is configured to capture purified aluminum 413 in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum 412 through the liquid electrolyte 410.
- the cathode structure 409b further defines a cathode flow path along which the purified aluminum 413 can flow from the upper portion 403 to the cathode molten material collection area 406b.
- the anode structure 408 defines an anode flow path along which impure aluminum 412 in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion to the anode molten material collection area 405.
- chambers 402a and 402b can include separate anode structures.
- anode structure 408 can be a common anode structure for chambers 402a and 402b and for cathode structures 409a and 409b.
- the anode structure 408 can include a first anode structure portion 421 and a second anode structure portion 422 and an anode reservoir 423 therebetween. The anode structure 408 can be configured to receive the impure aluminum 412 in the anode reservoir 423.
- the anode flow path can extend from the anode reservoir 423 through both the first anode structure portion 421 and the second anode structure portion 422 to the anode molten material collection area 405.
- the first anode structure portion 421 and the second anode structure portion 422 can comprise porous material and the impure aluminum 412 can flow therethrough.
- the anode structure 408 can include a anode reservoir bottom portion 425.
- the anode reservoir bottom portion 425 can prevent impure aluminum 412 from flowing through the anode reservoir bottom portion 425.
- the anode reservoir bottom portion 425 can comprise a nonporous material.
- the anode reservoir bottom portion can separate and electrically insulate the first anode structure portion 421 and the second anode structure portion 422 from the anode molten material collection area 405.
- system 400 can provide advantages, such as for example, redundancy. For example, if chamber 402a and/or cathode 409a requires maintenance, purification can continue in chamber 402b. Additionally or alternatively, both chambers 402a and 402b can operate simultaneously, which can increase the rate of aluminum purification of the system. It is to be understood that system 400 can include more than two chambers and/or anode structure/cathode structure pairs. Additionally or alternatively, and as described above chambers and/or anode structure/cathode structure pairs can be operated in series to achieve desired aluminum purification.
- purified aluminum 413 from cathode molten material collection area 406a and/or cathode molten material collection area 406b can be reintroduced to another anode structure within the system and subject to further purification, as described further herein.
- impure aluminum from the anode structure can be transferred to another cell for further purification.
- impure aluminum can be transferred from the anode structure of a first cell to the anode structure of a second cell.
- impure aluminum can be transferred from anode reservoir.
- impure aluminum can be transferred from anode molten material collection area.
- Impure aluminum can be transferred from the anode structure of the first cell to the anode structure of a second cell using standard metal transfer methods.
- impure aluminum can be syphoned periodically from the anode structure using standard metal transfer methods.
- impure aluminum can be allowed to steadily drain from the anode structure into a collection trough and/or sump for removal, such as to another anode structure. Transferring impure aluminum from the anode structure can prevent build up and/or concentration of impurities in the impure aluminum received at the anode structure.
- Aluminum purification cells can be operated in series at different temperatures.
- the aluminum purification cell temperature can be selected based on the concentration of aluminum in the impure aluminum to be introduced into the cell.
- a first cell can have a first cell temperature
- a second cell can have a second cell temperature
- the second cell temperature can be higher than the first cell temperature.
- cell temperature can be between temperatures of about 640°C to about 900°C depending on the concentration of aluminum in the impure aluminum to be introduced into the cell.
- Cell temperature as used herein refers to the temperature of liquid electrolyte in the cell.
- impure aluminum having a first concentration of aluminum can be introduced to a first cell and received by the anode structure of the first cell. As aluminum is extracted from the impure aluminum at the anode structure and captured at the cathode structure of the first cell, the concentration of aluminum in the impure aluminum at the anode structure of the first cell can decrease to a second, lower, concentration of aluminum.
- the impure aluminum having the second, lower, concentration of aluminum can be transferred from the anode structure of the first cell to a second cell where the impure aluminum can be received by a second anode structure.
- the second cell can have a higher temperature than the first cell to further purify the impure aluminum having the second, lower, concentration of aluminum.
- the purification system 500 comprises a first cell defining a first chamber 502a.
- the chamber 502a has an upper portion 503 and a lower portion 504.
- the lower portion 504 includes a cathode molten material collection area 506a.
- the lower portion 504 can further include an anode molten material collection area 505a.
- the anode molten material collection area 505a can be separated from the cathode molten material collection area 506a by a partition 507a disposed therebetween.
- the system 500 further includes an anode structure 508a disposed in the upper portion of the chamber 502a and vertically aligned above the lower portion 504.
- the anode structure 508a can be disposed in the upper portion of the chamber 502a and vertically aligned above the anode molten material collection area 505a.
- a cathode structure 509a is disposed in the upper portion of the chamber 502a and vertically aligned above the cathode molten material collection area 506a.
- a liquid electrolyte 510a is disposed within the chamber 502a in fluid communication with the anode structure 508a and the cathode structure 509a.
- the anode structure 508a is configured to receive impure aluminum 512a in a molten state having an impure aluminum density greater than the electrolyte density.
- the anode structure 508a can include a first anode structure portion 521a and a second anode structure portion 522a and an anode reservoir 523a therebetween.
- the anode structure 508a can receive impure aluminum 512a in the anode reservoir 523a.
- the anode structure 508a can define an anode flow path along which impure aluminum 512a in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion 503 to the anode molten material collection area.
- the anode flow path can extend from the anode reservoir 523a through the second anode structure portion 522a to the anode molten material collection area 505a.
- the cathode structure 509a is configured to capture purified aluminum 513a in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum 512a through the liquid electrolyte 510a.
- the cathode structure 509a further defines a cathode flow path along which the purified aluminum 513a can flow from the upper portion 503 to the cathode molten material collection area 506a.
- impure aluminum 512a having a first concentration of aluminum can be introduced to the anode structure 508a of the first cell.
- the concentration of aluminum in the impure aluminum 512a at the anode structure 508a of the first cell can decrease to a second, lower, concentration of aluminum.
- the impure aluminum 512a having the second, lower, concentration of aluminum can be transferred from the anode structure 508a of the first cell to a second cell where the impure aluminum can be received by a second anode structure 508b.
- system 500 further includes a second cell defining a second chamber 502b.
- the chamber 502b has an upper portion 503 and a lower portion 504.
- the lower portion 504 includes a cathode molten material collection area 506b.
- the lower portion 504 can further include an anode molten material collection area 505b.
- the anode molten material collection area 505b can be separated from the cathode molten material collection area 506b by a partition 507b disposed therebetween.
- the system 500 further includes a second anode structure 508b disposed in the upper portion of the second chamber 502b and vertically aligned above the lower portion 504.
- the second anode structure 508b can be disposed in the upper portion of the chamber 502a and vertically aligned above the anode molten material collection area 505b.
- a cathode structure 509b is disposed in the upper portion of the chamber 502b and vertically aligned above the cathode molten material collection area 506b.
- a liquid electrolyte 510b is disposed within the chamber 502b in fluid communication with the anode structure 508b and the cathode structure 509b.
- the anode structure 508b is configured to receive impure aluminum 512b in a molten state having an impure aluminum density greater than the electrolyte density.
- the anode structure 508b can receive impure aluminum 512a having the second, lower, concentration of aluminum from the anode structure 508a of the first cell.
- Aluminum can be transferred from the first anode structure 508a to the second anode structure 508b using any suitable method.
- a pump 516 can transfer aluminum from the first anode structure 508a to the second anode structure 508b as denoted by arrow 541.
- the anode structure 508b can include a first anode structure portion 521b and a second anode structure portion 522b and an anode reservoir 523b therebetween.
- the anode structure 508b can receive impure aluminum 512b in the anode reservoir 523b.
- the anode structure 508b can define an anode flow path along which impure aluminum 512b in a molten state having an impure aluminum density greater than the electrolyte density can flow from the upper portion 503 to the anode molten material collection area.
- the anode flow path can extend from the anode reservoir 523b through the second anode structure portion 522b to the anode molten material collection area 505b.
- the cathode structure 509b is configured to capture purified aluminum 513b in a molten state having a purified aluminum density greater than the electrolyte density from the impure aluminum 512b through the liquid electrolyte 510b.
- the cathode structure 509b further defines a cathode flow path along which the purified aluminum 513b can flow from the upper portion 503 to the cathode molten material collection area 506b.
- the first cell and first chamber 502a can be operated at a first cell temperature and the second cell and second chamber 502b can be operated at a second cell temperature.
- the second cell temperature can be higher than the first cell temperature.
- the impure aluminum 512b received at the second anode structure 508b can have a lower concentration of aluminum as compared to the impure aluminum 512a received at the first anode structure 508a.
- the cell temperature can be selected based on the concentration of impure aluminum to be purified, as described above.
- Operating aluminum purification cells in series at temperatures selected according to the concentration of aluminum in the impure aluminum can be beneficial for system efficiency.
- the operating temperature of a first cell having impure aluminum with a higher concentration of aluminum can be lower and can require less energy to operate.
- walls of the aluminum purification cell can include heat transfer systems to control the temperature of the aluminum purification cell.
- walls of the aluminum purification cell can include two plates with an interstitial space defined therebetween.
- the plates of the cell wall can include, for example, steel or high temperature alloy.
- the plates of the cell wall can include a graphite layer facing the interstitial space.
- coiled tubes can be included in the interstitial space.
- tubes can be coiled in a sinusoidal pattern within the interstitial space.
- the remainder of the interstitial space can be filled with conductive material, such as for example, graphite powder.
- Air or other gas can be flowed through the tubes to control the temperature of the cell.
- heated air or other gas can be flowed through the tubes to raise the temperature of the cell and cooled air can be flowed through the tubes to lower the temperature of the cell.
- the aluminum purification cell can be heated to desired temperature for cell startup. Additionally or alternatively, the aluminum purification cell can be cooled to maintain desired operating temperatures during steady-state operation of the aluminum purification cell.
- the disclosed subject matter further includes methods for purifying aluminum.
- Methods in accordance with the disclosed subject matter include operating an aluminum purification system having any of the features described above.
- Methods in accordance with the disclosed subject matter further include introducing impure aluminum in a molten state having an impure aluminum density greater than the electrolyte density into the chamber to be received by the anode structure, the anode structure defining an anode flow path along which the impure aluminum can flow from the upper portion to the anode molten material collection area.
- Methods further include capturing purified aluminum in a molten state having a purified aluminum density greater than the electrolyte density at the cathode structure from the impure aluminum through the liquid electrolyte, the cathode structure defining a cathode flow path along which the purified aluminum can flow from the upper portion to the cathode molten material collection area. Further, methods include collecting in the cathode molten material collection area purified aluminum released from the cathode structure.
- method 200 includes step 201 of operating an aluminum purification system.
- the aluminum purification system can include exemplary system 100 of aluminum purification, as shown in Fig. 1.
- Methods in accordance with the disclosed subject matter can be used with systems having any of the features described herein.
- the method further includes step 202 in which impure aluminum 112 in a molten state and having an impure aluminum density greater than the electrolyte density is introduced into the chamber 102 and received by the anode structure 108.
- Purified aluminum 113 is captured at the cathode structure 109 from the impure aluminum 112 through the liquid electrolyte 110, as shown in step 203.
- a voltage and/or current can be applied across the impure aluminum 112 at the anode structure 108 and the purified aluminum 113 at the cathode structure 109, and aluminum ions can flow from the anode structure 108 to the cathode structure 109 through the liquid electrolyte 110.
- purified aluminum 113 is released from the cathode structure 109 and collected in the cathode molten collection area 106.
- the system 100 can inlcude an anode molten material collection area 105 disposed underneath the anode structure 108.
- methods can further include removing impure molten aluminum 112 from the anode molten material collection area 105 through outlet 114 in fluid communication with the first molten material collection area 105.
- the removed impure molten aluminum 112 can be reintroduced into the chamber 102 and the anode structure 108, such as by using pump 116.
- the system 100 can include more than one anode structure and introducing impure molten aluminum 112 into the chamber 102 can further include introducing the impure molten aluminum 112 to a second anode structure.
- the system 100 includes one anode structure 108; however, additional anode structures can be included. The number of cells and anode structures can be selected based on the desired performance properties of the purification system.
- a cathode structure 109 is disposed in the upper portion of the chamber such that it is vertically aligned above the cathode molten material collection area 106.
- the system 100 includes one cathode structure 109; however, additional cathode structures can be included. The number of cells and cathode structures can be selected based on the desired performance properties of the purification system.
- the cathode structure 109 defines a cathode flow path along which purified aluminum can flow from the upper portion 103 to the cathode molten material collection area 106.
- purified aluminum can flow down the cathode structure 109 and drip into the cathode molten material collection area 106.
- the purified aluminum 113 can be removed from the cathode molten material collection area 106 through outlet 115 in fluid communication with the second molten material collection area 106.
- Systems and methods in accordance with the disclosed subject matter can be used to collect purified aluminum of high quality.
- systems in accordance with the disclosed subject matter can be used to process impure aluminum having at least 80 wt. % aluminum and produce aluminum having at least 99 wt. % of aluminum.
- the purified aluminum can have 99.99 wt. % aluminum.
- systems and methods in accordance with the disclosed subject matter can be used to efficiently purify aluminum.
- the energy consumption of an aluminum purification system can be expressed in kilowatt hours/kilogram of aluminum produced (kWh/kg).
- systems in accordance with the disclosed subject matter can produce purified aluminum at an energy consumption of from about 1.5 to 7 kWh/kg of purified aluminum captured at the cathode structure.
- Systems in accordance with the disclosed subject matter can provide improved efficiency.
- systems in accordance with the disclosed subject matter can include more conductive electrolyte and a smaller distance between the anode structure and cathode structure, which can improve system efficiency.
- liquid electrolytes having electrolyte density less than the density of purified aluminum can be more conductive than, for example, liquid electrolytes having electrolyte density greater than the density of purified aluminum, such as liquid electrolytes used in Hoopes cell configurations.
- Example 1
- the anode reservoir bottom portion 435 extended all the way to the bottom of the chamber to divide the anode molten material collection area 405 into two separate collection areas, one for each of chamber 402a and chamber 402b, respectively.
- the system included an anode structure having a porous second anode structure portion.
- the second anode structure portion comprised a graphite felt.
- the liquid electrolyte used was 66% LiF and 34% NasAlFe.
- the liquid electrolyte had a density of about 2.1 g/cm 3 .
- the system included an anode-cathode distance of about 4 cm.
- a Tungsten cathode structure was used on a first side of the anode structure for the first chamber, and a graphite cathode structure was used on a second side of the anode structure for the second chamber. Both chambers were operated cell temperatures of about 700°C.
- Impure aluminum was added to the system and received at the anode structure. The impure aluminum was about 95.3% Al. Purified aluminum was collected at the molten material collection area. The purified aluminum collected at the molten material collection area included fewer impurities as compared to the impure aluminum received at the anode structure of the exemplary system.
- the impurity reduction was as follows: Cu greater than about 97% reduction, Fe about 93% reduction, Mn about 98% reduction, Si about 96% reduction, Zn greater than about 96% reduction.
- systems and methods in accordance with the disclosed subject matter can be used without the need to modify the density of the impure aluminum feed material.
- impure aluminum feed material is frequently alloyed with another material, such as copper, to increase the density of the impure aluminum feed material. Alloying the impure aluminum can be required in Hoopes cell configurations, which rely on a liquid electrolyte having a density less than the impure aluminum feed material, and greater than the density of purified aluminum.
- Systems and methods in accordance with the disclosed subject matter include liquid electrolyte having a density less than the impure aluminum feed material and less than purified aluminum, which can alleviate the need to alloy the impure aluminum feed material or otherwise alter its density prior to introduction to the purification system.
- systems and methods in accordance with the disclosed subject matter can be configured for continuous operation.
- Systems and methods for continuous operation can provide advantages over other systems, such as the Hoopes cell, which can require batch processing and associated interruptions in aluminum purification.
- the aluminum in the anode layer at the bottom of the refining cell can become depleted over time and can require periodic exchanges of the aluminum-depleted anode layer with new impure aluminum and copper alloy material. Exchanging the depleted aluminum anode layer can require pauses in aluminum purification and can reduce overall system efficiency.
- the anode structure can be configured to continuously receive impure aluminum in a molten state such that impure aluminum can continuously flow along the anode flow path from the upper portion to the anode molten material collection area.
- impure aluminum can be continuously introduced and flown along the anode flow path, exchanging depleted input material with new impure aluminum input material can be avoided.
- the cathode structure can be configured to continuously capture purified aluminum in a molten state.
- impure aluminum feed materials can include aluminum, magnesium, lithium, and other metal materials.
- systems and methods have been described herein for capturing purified aluminum from impure aluminum feed materials.
- additional purified metals present in the feed material e.g., capture purified magnesium or lithium.
- additional materials of interest can be captured and separated from the impure aluminum feed material using additional processing, which can occur, for example, before or after introducing the impure aluminum material into systems and methods described herein for capturing purified aluminum.
- additional processing can be performed, for example, using chambers disclosed herein for capturing purified aluminum or similar.
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- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
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- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
Description
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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AU2023231135A AU2023231135A1 (en) | 2022-03-10 | 2023-03-10 | Systems and methods for purifying aluminum |
US18/430,884 US20240175161A1 (en) | 2022-03-10 | 2024-02-02 | Systems and methods for purifying aluminum |
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US202263318595P | 2022-03-10 | 2022-03-10 | |
US63/318,595 | 2022-03-10 |
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US18/430,884 Continuation US20240175161A1 (en) | 2022-03-10 | 2024-02-02 | Systems and methods for purifying aluminum |
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WO2023172717A1 true WO2023172717A1 (en) | 2023-09-14 |
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PCT/US2023/014946 WO2023172717A1 (en) | 2022-03-10 | 2023-03-10 | Systems and methods for purifying aluminum |
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US (1) | US20240175161A1 (en) |
AR (1) | AR128753A1 (en) |
AU (1) | AU2023231135A1 (en) |
WO (1) | WO2023172717A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4214955A (en) * | 1979-01-02 | 1980-07-29 | Aluminum Company Of America | Electrolytic purification of metals |
US4601804A (en) * | 1983-07-27 | 1986-07-22 | Swiss Aluminium Ltd. | Cell for electrolytic purification of aluminum |
US20100276297A1 (en) * | 2009-04-30 | 2010-11-04 | Metal Oxygen Separation Technologies, Inc. | Primary production of elements |
-
2023
- 2023-03-10 WO PCT/US2023/014946 patent/WO2023172717A1/en active Application Filing
- 2023-03-10 AU AU2023231135A patent/AU2023231135A1/en active Pending
- 2023-03-10 AR ARP230100595A patent/AR128753A1/en unknown
-
2024
- 2024-02-02 US US18/430,884 patent/US20240175161A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4214955A (en) * | 1979-01-02 | 1980-07-29 | Aluminum Company Of America | Electrolytic purification of metals |
US4601804A (en) * | 1983-07-27 | 1986-07-22 | Swiss Aluminium Ltd. | Cell for electrolytic purification of aluminum |
US20100276297A1 (en) * | 2009-04-30 | 2010-11-04 | Metal Oxygen Separation Technologies, Inc. | Primary production of elements |
Also Published As
Publication number | Publication date |
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US20240175161A1 (en) | 2024-05-30 |
AR128753A1 (en) | 2024-06-12 |
AU2023231135A1 (en) | 2024-09-05 |
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