US20070131560A1 - Electrochemical reduction of metal oxides - Google Patents
Electrochemical reduction of metal oxides Download PDFInfo
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- US20070131560A1 US20070131560A1 US11/522,761 US52276106A US2007131560A1 US 20070131560 A1 US20070131560 A1 US 20070131560A1 US 52276106 A US52276106 A US 52276106A US 2007131560 A1 US2007131560 A1 US 2007131560A1
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- metal oxide
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- 229910044991 metal oxide Inorganic materials 0.000 title claims abstract description 34
- 150000004706 metal oxides Chemical class 0.000 title claims abstract description 34
- 230000009467 reduction Effects 0.000 title claims description 11
- 239000003792 electrolyte Substances 0.000 claims abstract description 62
- 239000000843 powder Substances 0.000 claims abstract description 60
- 238000000034 method Methods 0.000 claims abstract description 39
- 230000008569 process Effects 0.000 claims abstract description 39
- 239000000463 material Substances 0.000 claims abstract description 7
- 239000007787 solid Substances 0.000 claims abstract description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 35
- 239000002002 slurry Substances 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 16
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 13
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 13
- 239000001110 calcium chloride Substances 0.000 claims description 13
- 230000037361 pathway Effects 0.000 claims description 9
- 238000000354 decomposition reaction Methods 0.000 claims description 8
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 4
- 230000002411 adverse Effects 0.000 claims description 3
- 238000005245 sintering Methods 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 2
- 238000010924 continuous production Methods 0.000 claims 1
- 238000002474 experimental method Methods 0.000 description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 5
- 229910052719 titanium Inorganic materials 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000011160 research Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 238000013019 agitation Methods 0.000 description 1
- LLSDKQJKOVVTOJ-UHFFFAOYSA-L calcium chloride dihydrate Chemical compound O.O.[Cl-].[Cl-].[Ca+2] LLSDKQJKOVVTOJ-UHFFFAOYSA-L 0.000 description 1
- 229940052299 calcium chloride dihydrate Drugs 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/129—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds by dissociation, e.g. thermic dissociation of titanium tetraiodide, or by electrolysis or with the use of an electric arc
-
- 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
- C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
- C25C3/28—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium of titanium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
- C25C5/04—Electrolytic production, recovery or refining of metal powders or porous metal masses from melts
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
- C22B4/08—Apparatus
Definitions
- the present invention relates to electrochemical reduction of metal oxides.
- the present invention relates particularly to electrochemical reduction of metal oxides in the form of powder to produce metal having a low oxygen concentration, typically no more than 0.2% by weight.
- the present invention was made during the course of an on-going research project on electrochemical reduction of metal oxides being carried out by the applicant.
- the research project has focused on the reduction of titanium oxide, more specifically titania (TiO 2 ).
- the CaCl 2 -based electrolyte used in the experiments was a commercially available source of CaCl 2 , namely calcium chloride dihydrate, which decomposed on heating and produced a very small amount of CaO.
- the applicant operated the electrolytic cells at a potential above the decomposition potential of CaO and below the decomposition potential of CaCl 2 .
- the applicant operated the cells under a wide range of different operating set-ups and conditions.
- the present invention was made unexpectedly in two experiments on sub-micron powders of pigment grade titania.
- the powders were mixed with molten CaCl 2 -based electrolyte containing CaO in electrolytic cells comprising anodes and cathodes in contact with the electrolyte/powder baths.
- the applicant found unexpectedly that the titania powders were successfully reduced in the molten electrolyte baths.
- the applicant also found unexpectedly that there was very little carbon produced in the experiments that was retained in the cells—this is a potentially important finding given that carbon contamination can be significant. The applicant had not expected to achieve these results.
- a process for electrochemically reducing metal oxide feed material in a solid state which includes agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across (a) a cathode in contact with the electrolyte and (b) an anode and electrochemically reducing the metal oxides.
- FIG. 1 is a schematic of an apparatus for practicing the present invention.
- the present invention includes a process for electrochemically reducing metal oxide feed material in a solid state.
- the process includes agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across (a) a cathode in contact with the electrolyte and (b) an anode and electrochemically reducing the metal oxides.
- the applicant speculates that the agitation caused intermittent contact between the powder particles and the cathode that was sufficient to enable reduction of titania powders and restrict sintering of the powder particles together that could adversely affect the reduction of unreduced or partially reduced powders.
- the particle size of the powders is selected so that the electrolyte and the powders form a slurry, i.e. a two phase mixture, in which the powder particles are suspended in the electrolyte.
- the electrolyte and the metal oxide powders may be agitated by any suitable means.
- the electrolyte and the metal oxide powders may be agitated by physical means, such as a stirrer.
- the electrolyte and the metal oxides powders may be agitated by gas injection.
- the metal oxide powders may be any suitable metal oxide. As is indicated above, the present invention has particular application to solid state reduction of titanium oxide particles, especially titania particles.
- the electrolyte is a CaCl 2 -based electrolyte containing CaO.
- the powders are sub-micron size.
- the process comprises applying a potential across the anode and the cathode that is above the decomposition potential of CaO and below the decomposition of CaCl 2 .
- the process may be carried out on a batch basis, a semi-continuous basis, and a continuous basis.
- the process may be carried out by positioning a member such as bar, plate, or sheet in contact with the electrolyte so that reduced powders can deposit on the member.
- the process comprises removing the member from the electrolyte and stripping deposited reduced powders from the members.
- the process may be carried out in a cell that contains a bath of electrolyte and metal oxide powders, an anode, and a cathode.
- the anode may be made from any suitable material.
- the anode may be a consumable or a non-consumable anode.
- the anode is a consumable anode.
- the cathode may be made from any suitable material.
- the process may be carried out as a multi-stage process with electrolyte and partially reduced and unreduced powders in a slurry form being transferred from a first stage to one or more than one successive stage in the process and being reduced in each stage.
- the multi-stage process may be carried out in the above-described cell, with discharge and recycling of the slurry to the cell.
- the multi-stage process may be carried out in a series of the above-described cells.
- the process is not confined to being carried out in the above-described cell.
- the process may be carried out on a continuous basis by passing a slurry of the electrolyte and metal oxide powders through a reactor, such as a pipe reactor, that defines a pathway for flow of the slurry between an inlet and an outlet and includes one or more than one anode and one or more than one cathode along the length of the pathway.
- the reactor may include agitating the slurry by a means, such as baffles or the like in the pathway that causes the slurry to flow in a turbulent flow pattern along the pathway.
- the process may include agitating the slurry by introducing the slurry in a turbulent flow into the reactor.
- the process comprises separating reduced powders from the electrolyte downstream of the outlet of the pathway and processing the reduced powders as required.
- an apparatus for electrochemically reducing metal oxide powders such as titanium oxide powders, which includes (a) a means for containing a bath of a molten electrolyte and metal oxide particles in the electrolyte, (b) a cathode in contact with the electrolyte, (c) an anode, (d) a means for applying a potential across the anode and the cathode, and (e) a means for agitating the electrolyte.
- the apparatus may be adapted to operate on a batch basis, a semi-continuous basis, or a continuous basis.
- the means for applying a potential across the anodes and the cathode includes (a) a power source and (b) an electrical circuit that electrically interconnects the power source, the anodes, and the cathode.
- the basic cell configuration of (a) a means for containing a bath of a molten electrolyte and metal oxide particles in the electrolyte, (b) a cathode in contact with the electrolyte, (c) an anode, (d) a means for applying a potential across the anode and the cathode is as described by way of example in other patent families of the applicant such as US 2004/0247478 (WO2003/016594), WO2003/076690, US 2006/0180462 (WO2004/035873) and US 2005/0050989 (WO2004/053201), each of which is incorporated herein by reference.
- the apparatus 10 includes a crucible 12 for containing a bath of molten electrolyte 14 and metal oxide particles 16 in the electrolyte 14 .
- the crucible may have a lid 13 .
- the crucible 12 and lid 13 may be formed from any suitable material such as graphite.
- a cathode 18 is in contact with the electrolyte 14 and may optionally have an insulator 20 surrounding the cathode.
- An anode is formed from the crucible by a rod 22 , which may be formed from stainless steel and may be in electrical contact with a DC power supply 24 and the crucible 12 .
- a thermocouple 26 may be provided in close proximity to the cathode 18 . The thermocouple may also be surrounded by an insulator 20 .
- the present invention was made unexpectedly in two experiments in which sub-micron powders of pigment grade titania were reduced in electrolytic cells containing baths of molten CaCl 2 -based electrolyte containing CaO, anodes and cathodes.
- the anode and the cathode were arranged to extend into the cell and the cathode had a relatively large surface area compared to the size of the cell.
- the titania powders were 10% by weight of the total weight of the powders and the electrolyte.
- the titanium powders were sub-micron sized.
- the cell was operated at a constant potential of 3 V for a period of 7 hours. The cell achieved currents of up to 8 A during the experiment.
- the wall of the cell formed the cathode and the anode was arranged to extend into the cell.
- the solids loading was 5% in this experiment.
- the titania powders were 5% by weight of the total weight of the powders and the electrolyte.
- the titania powders were sub-micron size.
- the cell was operated at a constant potential of 3 V for a period of 7 hours. The cell achieved currents of up to 30 A during the experiment.
- the titania powders were reduced by up to 50% by the end of the first experiment.
- the titania powders were reduced up to 95% by the end of the second experiment.
- the applicant allowed the cell to cool to room temperature and then sectioned the cell.
- the applicant found that the cell comprised a layer of titanium metal powders on the bottom wall of the cell and a layer of substantially “clean” electrolyte on the metal layer.
- the applicant also found that the side walls of the cell had a layer of titanium carbide.
Abstract
A process for electrochemically reducing metal oxide feed material in a solid state is disclosed. The process includes the steps of agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across a cathode in contact with the electrolyte and an anode and electrochemically reducing the metal oxides.
Description
- The present application is a continuation-in-part application of and claims priority to PCT/AU2005/000409 published in English on Sep. 29, 2005 as PCT WO 2005/090640 and from AU 2004901524 filed Mar. 22, 2004, the entire contents of each are incorporated herein by reference in their entirety.
- The present invention relates to electrochemical reduction of metal oxides. The present invention relates particularly to electrochemical reduction of metal oxides in the form of powder to produce metal having a low oxygen concentration, typically no more than 0.2% by weight.
- The present invention was made during the course of an on-going research project on electrochemical reduction of metal oxides being carried out by the applicant. The research project has focused on the reduction of titanium oxide, more specifically titania (TiO2).
- During the course of the research project the applicant has carried out a series of experiments investigating the reduction of titania in electrolytic cells comprising a pool of molten CaCl2-based electrolyte, an anode formed from graphite, and a range of cathodes.
- The CaCl2-based electrolyte used in the experiments was a commercially available source of CaCl2, namely calcium chloride dihydrate, which decomposed on heating and produced a very small amount of CaO.
- The applicant operated the electrolytic cells at a potential above the decomposition potential of CaO and below the decomposition potential of CaCl2.
- The applicant found that the cells electrochemically reduced titania to titanium with low concentrations of oxygen, i.e. concentrations less than 0.2 wt. %, at these potentials.
- The applicant operated the cells under a wide range of different operating set-ups and conditions.
- The present invention was made unexpectedly in two experiments on sub-micron powders of pigment grade titania. The powders were mixed with molten CaCl2-based electrolyte containing CaO in electrolytic cells comprising anodes and cathodes in contact with the electrolyte/powder baths. The applicant found unexpectedly that the titania powders were successfully reduced in the molten electrolyte baths. The applicant also found unexpectedly that there was very little carbon produced in the experiments that was retained in the cells—this is a potentially important finding given that carbon contamination can be significant. The applicant had not expected to achieve these results.
- The unexpected success of the experiments opens up the possibility of commercial production of metals from metal oxides such as titania on a far more straightforward basis than was hitherto thought to be possible.
- According to the present invention there is provided a process for electrochemically reducing metal oxide feed material in a solid state, which includes agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across (a) a cathode in contact with the electrolyte and (b) an anode and electrochemically reducing the metal oxides.
- Additional features and benefits of the present invention are described and will be apparent from the accompanying drawings and detailed description below.
- The accompanying drawings illustrate embodiments of the invention according to the practical application of the principles described and shown.
-
FIG. 1 is a schematic of an apparatus for practicing the present invention. - The present invention includes a process for electrochemically reducing metal oxide feed material in a solid state. The process includes agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across (a) a cathode in contact with the electrolyte and (b) an anode and electrochemically reducing the metal oxides. The applicant speculates that the agitation caused intermittent contact between the powder particles and the cathode that was sufficient to enable reduction of titania powders and restrict sintering of the powder particles together that could adversely affect the reduction of unreduced or partially reduced powders.
- Preferably, the particle size of the powders is selected so that the electrolyte and the powders form a slurry, i.e. a two phase mixture, in which the powder particles are suspended in the electrolyte.
- The electrolyte and the metal oxide powders may be agitated by any suitable means. By way of example, the electrolyte and the metal oxide powders may be agitated by physical means, such as a stirrer. Alternatively, or in addition, the electrolyte and the metal oxides powders may be agitated by gas injection.
- The applicant has found in the two experiments described above that gas injection enabled segregation of carbon contaminant formed in the experiments to the surface of the bath and titanium to the bottom of the bath. This is an important feature in terms of separating carbon and titanium in the process.
- The metal oxide powders may be any suitable metal oxide. As is indicated above, the present invention has particular application to solid state reduction of titanium oxide particles, especially titania particles.
- Preferably, the electrolyte is a CaCl2-based electrolyte containing CaO. In the case of a CaCl2-based electrolyte containing CaO, preferably the powders are sub-micron size. In the case of a CaCl2-based electrolyte containing CaO, preferably the process comprises applying a potential across the anode and the cathode that is above the decomposition potential of CaO and below the decomposition of CaCl2.
- The process may be carried out on a batch basis, a semi-continuous basis, and a continuous basis. The process may be carried out by positioning a member such as bar, plate, or sheet in contact with the electrolyte so that reduced powders can deposit on the member. With this arrangement, the process comprises removing the member from the electrolyte and stripping deposited reduced powders from the members. The process may be carried out in a cell that contains a bath of electrolyte and metal oxide powders, an anode, and a cathode.
- The anode may be made from any suitable material. The anode may be a consumable or a non-consumable anode. Typically, the anode is a consumable anode. The cathode may be made from any suitable material.
- The process may be carried out as a multi-stage process with electrolyte and partially reduced and unreduced powders in a slurry form being transferred from a first stage to one or more than one successive stage in the process and being reduced in each stage. The multi-stage process may be carried out in the above-described cell, with discharge and recycling of the slurry to the cell. The multi-stage process may be carried out in a series of the above-described cells.
- The process is not confined to being carried out in the above-described cell. By way of example, the process may be carried out on a continuous basis by passing a slurry of the electrolyte and metal oxide powders through a reactor, such as a pipe reactor, that defines a pathway for flow of the slurry between an inlet and an outlet and includes one or more than one anode and one or more than one cathode along the length of the pathway. The reactor may include agitating the slurry by a means, such as baffles or the like in the pathway that causes the slurry to flow in a turbulent flow pattern along the pathway. Alternatively, or in addition, the process may include agitating the slurry by introducing the slurry in a turbulent flow into the reactor.
- When operated on a continuous basis preferably the process comprises separating reduced powders from the electrolyte downstream of the outlet of the pathway and processing the reduced powders as required.
- According to the present invention there is also provided an apparatus for electrochemically reducing metal oxide powders, such as titanium oxide powders, which includes (a) a means for containing a bath of a molten electrolyte and metal oxide particles in the electrolyte, (b) a cathode in contact with the electrolyte, (c) an anode, (d) a means for applying a potential across the anode and the cathode, and (e) a means for agitating the electrolyte. The apparatus may be adapted to operate on a batch basis, a semi-continuous basis, or a continuous basis.
- Preferably, the means for applying a potential across the anodes and the cathode includes (a) a power source and (b) an electrical circuit that electrically interconnects the power source, the anodes, and the cathode.
- The basic cell configuration of (a) a means for containing a bath of a molten electrolyte and metal oxide particles in the electrolyte, (b) a cathode in contact with the electrolyte, (c) an anode, (d) a means for applying a potential across the anode and the cathode is as described by way of example in other patent families of the applicant such as US 2004/0247478 (WO2003/016594), WO2003/076690, US 2006/0180462 (WO2004/035873) and US 2005/0050989 (WO2004/053201), each of which is incorporated herein by reference.
- Turning to
FIG. 1 , a batch apparatus is shown. Theapparatus 10 includes acrucible 12 for containing a bath ofmolten electrolyte 14 andmetal oxide particles 16 in theelectrolyte 14. The crucible may have alid 13. Thecrucible 12 andlid 13 may be formed from any suitable material such as graphite. Acathode 18 is in contact with theelectrolyte 14 and may optionally have aninsulator 20 surrounding the cathode. An anode is formed from the crucible by arod 22, which may be formed from stainless steel and may be in electrical contact with aDC power supply 24 and thecrucible 12. Athermocouple 26 may be provided in close proximity to thecathode 18. The thermocouple may also be surrounded by aninsulator 20. - As is indicated above, the present invention was made unexpectedly in two experiments in which sub-micron powders of pigment grade titania were reduced in electrolytic cells containing baths of molten CaCl2-based electrolyte containing CaO, anodes and cathodes.
- In the first experiment, the anode and the cathode were arranged to extend into the cell and the cathode had a relatively large surface area compared to the size of the cell. The titania powders were 10% by weight of the total weight of the powders and the electrolyte. The titanium powders were sub-micron sized. The cell was operated at a constant potential of 3 V for a period of 7 hours. The cell achieved currents of up to 8 A during the experiment.
- In the second experiment, which was run after the success of the first experiment, the wall of the cell formed the cathode and the anode was arranged to extend into the cell. The solids loading was 5% in this experiment. In other words, the titania powders were 5% by weight of the total weight of the powders and the electrolyte. The titania powders were sub-micron size. The cell was operated at a constant potential of 3 V for a period of 7 hours. The cell achieved currents of up to 30 A during the experiment.
- In both experiments: (i) the bath was agitated during the course of the experiments by inert gas injection to ensure movement of the powders within the bath; (ii) the operating potential of 3 V is a potential above the decomposition potential of CaO in the electrolyte and below the decomposition potential of CaCl2; and (iii) there was a build-up of reduced powders on the cathode, although without any apparent sintering of reduced powders that restricted reaction rates or otherwise adversely affected the experiments.
- Some regions of the titania powders were reduced by up to 50% by the end of the first experiment. The titania powders were reduced up to 95% by the end of the second experiment. At the end of the second experiment, the applicant allowed the cell to cool to room temperature and then sectioned the cell. The applicant found that the cell comprised a layer of titanium metal powders on the bottom wall of the cell and a layer of substantially “clean” electrolyte on the metal layer. The applicant also found that the side walls of the cell had a layer of titanium carbide.
- Many modifications may be made to the present invention described above without departing from the spirit and scope of the invention. While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Claims (17)
1. A process for electrochemically reducing metal oxide feed material in a solid state comprising agitating an electrolyte and metal oxide powders in the electrolyte and applying an electrical potential across (a) a cathode in contact with the electrolyte and (b) an anode and electrochemically reducing the metal oxides.
2. The process defined in claim 1 includes agitating an electrolyte and metal oxide powders to an extent required to cause intermittent contact between the powder particles and the cathode that is sufficient to enable reduction of titania powders and restrict sintering of the powder particles together that could adversely affect the reduction of unreduced or partially reduced powders.
3. The process defined in claim 1 includes selecting the particle size of the powders so that the electrolyte and the powders form a slurry in which the powder particles are suspended in the electrolyte.
4. The process defined in claim 1 includes agitating the electrolyte and the metal oxide powders by physical means or by gas injection.
5. The process defined in claim 1 wherein the powders are sub-micron size.
6. The process defined in claim 1 wherein the electrolyte is a CaCl2-based electrolyte containing CaO.
7. The process defined in claim 6 includes applying a potential across the anode and the cathode that is above the decomposition potential of CaO and below the decomposition of CaCl2.
8. The process defined in claim 1 includes positioning a member in contact with the electrolyte so that reduced powders can deposit on the member.
9. The process defined in claim 8 includes removing the member from the electrolyte and stripping deposited reduced powders from the member.
10. The process defined in claim 1 wherein the process is a multi-stage process with electrolyte and partially reduced and unreduced powders in a slurry form being transferred from a first stage to one or more than one successive stage in the process and being reduced in each stage.
11. The process defined in claim 1 wherein the process is a continuous process that includes passing a slurry of the electrolyte and metal oxide powders through a reactor that defines a pathway for flow of the slurry between an inlet and an outlet and includes one or more than one anode and one or more than one cathode in the pathway.
12. The process defined in claim 11 includes agitating the slurry to cause the slurry to flow in a turbulent flow pattern along the pathway.
13. The process defined in claim 11 includes agitating the slurry by introducing the slurry in a turbulent flow into the reactor.
14. The process defined in claim 11 , when operated on a continuous basis, includes separating reduced powders from the electrolyte downstream of the outlet of the pathway and processing the reduced powders as required.
15. The process defined in claim 1 wherein the metal oxide particles are titanium oxide particles.
16. An apparatus for electrochemically reducing metal oxide powders comprising:
(a) a means for containing a bath of a molten electrolyte and metal oxide particles in the electrolyte,
(b) a cathode in contact with the electrolyte,
(c) an anode,
(d) a means for applying a potential across the anode and the cathode, and
(e) a means for agitating the electrolyte.
17. The apparatus defined in claim 16 wherein the means for applying the potential across the anodes and the cathode includes (a) a power source and (b) an electrical circuit that electrically interconnects the power source, the anodes, and the cathode.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2004901524 | 2004-03-22 | ||
AU2004901524A AU2004901524A0 (en) | 2004-03-22 | Electrochemical reduction of metal oxides | |
PCT/AU2005/000409 WO2005090640A1 (en) | 2004-03-22 | 2005-03-22 | Electrochemical reduction of metal oxides |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2005/000409 Continuation-In-Part WO2005090640A1 (en) | 2004-03-22 | 2005-03-22 | Electrochemical reduction of metal oxides |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070131560A1 true US20070131560A1 (en) | 2007-06-14 |
Family
ID=34993732
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/522,761 Abandoned US20070131560A1 (en) | 2004-03-22 | 2006-09-18 | Electrochemical reduction of metal oxides |
Country Status (5)
Country | Link |
---|---|
US (1) | US20070131560A1 (en) |
JP (1) | JP2007529631A (en) |
CN (1) | CN1961098A (en) |
RU (1) | RU2006137273A (en) |
WO (1) | WO2005090640A1 (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060191799A1 (en) * | 2002-10-09 | 2006-08-31 | Les Strezov | Electrochemical reduction of metal oxides |
US20060226027A1 (en) * | 2003-06-20 | 2006-10-12 | Shook Andrew A | Electrochemical reduction of metal oxides |
US20070181438A1 (en) * | 2004-06-22 | 2007-08-09 | Olivares Rene I | Electrochemical Reduction of Metal Oxides |
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RU2495159C1 (en) * | 2012-02-14 | 2013-10-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Национальный исследовательский технологический университет "МИСиС" | Method for obtaining magnesium-calcium alloys by electrolysis |
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US9562296B2 (en) | 2010-11-02 | 2017-02-07 | I'msep Co., Ltd. | Production method for silicon nanoparticles |
US20150050816A1 (en) * | 2013-08-19 | 2015-02-19 | Korea Atomic Energy Research Institute | Method of electrochemically preparing silicon film |
US20160047054A1 (en) * | 2014-08-15 | 2016-02-18 | Worcester Polytechnic Institute | Iron powder production via flow electrolysis |
US20210009415A1 (en) * | 2018-07-10 | 2021-01-14 | Northeastern University | Electrochemical method for high-temperature molten salt electrolysis in humid atmosphere |
US11897780B2 (en) * | 2018-07-10 | 2024-02-13 | Northeastern University | Electrochemical method for high-temperature molten salt electrolysis in humid atmosphere |
Also Published As
Publication number | Publication date |
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CN1961098A (en) | 2007-05-09 |
RU2006137273A (en) | 2008-04-27 |
WO2005090640A1 (en) | 2005-09-29 |
JP2007529631A (en) | 2007-10-25 |
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