US20040237710A1 - Electrolytic reducion of metal oxides - Google Patents
Electrolytic reducion of metal oxides Download PDFInfo
- Publication number
- US20040237710A1 US20040237710A1 US10/474,746 US47474604A US2004237710A1 US 20040237710 A1 US20040237710 A1 US 20040237710A1 US 47474604 A US47474604 A US 47474604A US 2004237710 A1 US2004237710 A1 US 2004237710A1
- Authority
- US
- United States
- Prior art keywords
- metal
- electrolyte
- cell
- metal oxide
- method defined
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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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
-
- 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
-
- 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
- C25C3/04—Electrolytic production, recovery or refining of metals by electrolysis of melts of magnesium
Abstract
Description
- The present invention relates to electrolytic reduction of metal oxides to produce substantially pure metals.
- In particular, the present invention relates to electrolytic reduction of aluminium and magnesium oxides using a CaCl2 electrolyte.
- The present invention was made during the course of an on-going research project on the electrolytic reduction of metal oxides using CaCl2-based electrolyte being carried out by the applicant.
- The research project investigated electrolytic reduction of a range of metal oxides in electrolyte cells based on the use of using CaCl2 electrolyte.
- The CaCl2 electrolyte was a commercially available source of CaCl2, namely calcium chloride dihydrate, that 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 could electrolytically reduce a range of metal oxides to metals with very low concentrations of oxygen.
- The present invention provides, in broad terms, a method of electrolytically reducing a metal oxide to produce a metal in an electrolytic cell, which method includes electrolytically reducing the metal oxide in an electrolytic cell that includes (a) a pool of molten metal, the metal being the metal of the metal oxide to be reduced, the molten metal pool forming a cathode of the cell, (b) a pool of molten electrolyte in contact with the molten metal, the electrolyte containing alkali and/or alkaline earth halides, (c) an anode extending into the electrolyte, and (d) a body of metal oxide to reduced in contact with the molten metal and the electrolyte.
- In the above method electrolytic reduction of metal oxide takes place where there is contact between (i) the molten metal, (ii) the metal oxide, and (iii) the electrolyte.
- Preferably the metal oxide body has a geometric shape that maximizes contact between (i) the molten metal, (ii) the metal oxide, and (iii) the electrolyte.
- Preferably the method includes feeding the metal oxide body into the electrolytic cell to maintain contact of the metal oxide and the molten metal.
- The metal oxide body may be in many forms, including rods, plates, blocks and the like, which can be readily immersed into the electrolyte and brought into contact with the molten metal.
- Preferably the method includes maintaining the cell temperature above the melting points of the electrolyte and the metal of the metal oxide to be reduced.
- Preferably the method includes operating the cell at a potential that is above a decomposition potential of at least one constituent of the electrolyte so that there are cations of a metal other than that of the cathode metal oxide in the electrolyte.
- Preferably the metal oxide is an aluminium oxide or a magnesium oxide.
- In a situation in which the metal oxide is a aluminium oxide or magnesium oxide it is preferred that the electrolyte be a CaCl2-based electrolyte that includes CaO as one of the constituents.
- In such a situation it is preferred that the cell potential be above the decomposition potential for CaO.
- It is also preferred that the cell potential be below the decomposition potential for CaCl2.
- It is preferred that the cell potential be less than 3.0V.
- It is preferred particularly that the cell potential be below 2.5V.
- It is preferred more particularly that the cell potential be below 2.0V.
- It is preferred that the cell potential be at least 1.5V.
- The CaCl2-based electrolyte may be a commercially available source of CaCl2, such as calcium chloride dihydrate, that partially decomposes on heating and produces CaO or otherwise includes CaO.
- Alternatively, or in addition, the CaCl2-based electrolyte may include CaCl2 and CaO that are added separately or pre-mised to form the electrolyte.
- At this stage, the applicant does not have a clear understanding of the electrolytic cell mechanism when the cell is operated at a potential at which CaCl2-based electrolyte partially decomposes. Nevertheless, whilst not wishing to be bound by the comments in this paragraph, the applicant offers the following comments by way of an outline of a possible cell mechanism. The applicant believes that operating the electrolytic cell above a potential at which CaCl2-based electrolyte partially decomposes produces Ca++ cations that migrate to the vicinity of the metal oxide in contact with the molten metal cathode and provide a driving force that facilitates extraction of O−− anions produced by electrolytic reduction to metal of metal oxide in contact with the molten metal cathode. The applicant also believes that the O−− anions, once extracted from the metal oxide, migrate to the anode and react with anode carbon and produce CO and release electrons that facilitate electrolytic reduction of metal oxide to metal. The experimental work carried out by the applicant produced evidence of Ca metal in the electrolyte. The applicant believes that the Ca metal was the result of electrodeposition of Ca++ cations as Ca metal on electrically conductive sections of the cathode and that at least part of the Ca metal dissolved in the electrolyte and migrated to the vicinity of the metal oxide in the cathode and participated in chemical reduction of oxides.
- It is preferred that the anode be graphite.
- Preferably the cell includes a base and side walls extending upwardly from the base formed from graphite.
- Preferably the cell includes at least one tap hole for molten metal in one of the side walls and the method includes removing molten metal continuously or periodically.
- The above-described method may be started-up in a number of ways.
- One option is to introduce the (pure) metal and the electrolyte in solid state into the cell and subsequently heat the entire system to melt the metal and the electrolyte.
- Another option is to introduce molten metal and molten electrolyte separately into the cell.
- The following example illustrates an application of the invention in the process of reducing aluminium oxide (alumina) into substantially pure aluminium using an electrolytic cell as illustrated in FIG. 1.
- FIG. 1 is a schematic illustration of an electrolytic cell5 that can be scaled-up in application of the present invention.
- Whilst the example described below relates to the reduction of alumina, the basic principle is equally applicable to other metals, particularly low melting point metals, more particularly magnesium.
- The electrolytic cell5 of FIG. 1 includes a
graphite crucible 10 that has abase 21,side walls 31, and a tapping/discharge opening indicated as 12 in one of theside walls 31. - The electrolytic cell5 further includes a bath of molten CaCl2 electrolyte 13 in the crucible and a
graphite electrode 11 immersed in themolten electrolyte 13. Thegraphite electrode 11 forms the anode of the cell 5. - The electrolytic cell5 further includes a
pool 15 of molten aluminium in a lower section of thecrucible 10. Themolten aluminium pool 15 forms the cathode of the cell. - The electrolytic cell further includes a
body 14 that consists of or incorporates alumina (Al2O3) to be reduced and extends into theelectrolyte 13 and contacts themolten aluminium cathode 15. The alumina is shaped as a rod, sheet or prismatic body.Alumina body 14 is held in an appropriate manner to allow controlled movement into and away from the crucible interior as indicated by thearrow 16. - The electrolytic cell5 further includes a
suitable power source 18 connected to theanode 11 and to themolten aluminium cathode 15. - The
molten aluminium cathode 15 is required in order to initiate electrolytic reduction of the alumina in thealumina body 14 to aluminium. The electrolytic reduction process is carried out at an elevated temperature of around 950° C. at which the CaCl2 electrolyte is and remains molten. On immersion of thealumina body 14 into theelectrolyte 13 and subsequent contact of thealumina body 14 with themolten aluminium cathode 15, reduction of the alumina takes place. Since the process temperatures are above the melting point of aluminium, the latter will melt into thebath 15 and the bath level withincrucible 10 will tend to rise. - In order to maintain optimum reduction conditions, the
alumina body 14 is moved at a rate commensurate with the melting-off rate of aluminium from thealumina body 14 and the build-up of aluminium so that immersion of thealumina body 14 in the molten aluminium is kept at a minimum. - The process may be operated in a continuous mode by removing molten aluminium through
tap hole 12 and positioningadditional alumina bodies 14 in theelectrolyte 13 to replacebodies 14 that are consumed in the reduction process. - Many modifications may be made to the embodiment of the present invention described above without departing from the spirit and scope of the present invention.
Claims (15)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/924,808 US20080110764A1 (en) | 2001-04-10 | 2007-10-26 | Electrolytic Reduction of Metal Oxides |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AUPR4439 | 2001-04-10 | ||
AUPR4439A AUPR443901A0 (en) | 2001-04-10 | 2001-04-10 | Method for reduction of metal oxides to pure metals |
PCT/AU2002/000456 WO2002083989A1 (en) | 2001-04-10 | 2002-04-10 | Electrolytic reduction of metal oxides |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/924,808 Continuation US20080110764A1 (en) | 2001-04-10 | 2007-10-26 | Electrolytic Reduction of Metal Oxides |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040237710A1 true US20040237710A1 (en) | 2004-12-02 |
Family
ID=3828435
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/474,746 Abandoned US20040237710A1 (en) | 2001-04-10 | 2002-04-10 | Electrolytic reducion of metal oxides |
US11/924,808 Abandoned US20080110764A1 (en) | 2001-04-10 | 2007-10-26 | Electrolytic Reduction of Metal Oxides |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/924,808 Abandoned US20080110764A1 (en) | 2001-04-10 | 2007-10-26 | Electrolytic Reduction of Metal Oxides |
Country Status (9)
Country | Link |
---|---|
US (2) | US20040237710A1 (en) |
EP (1) | EP1392890A4 (en) |
JP (1) | JP2004523662A (en) |
CN (1) | CN1509346A (en) |
AU (1) | AUPR443901A0 (en) |
CA (1) | CA2443953A1 (en) |
NO (1) | NO20034548L (en) |
WO (1) | WO2002083989A1 (en) |
ZA (1) | ZA200307978B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100323253A1 (en) * | 2006-02-22 | 2010-12-23 | University Of Utah Resarch Foundation | Systems and Methods for Hydrogen Storage and Generation from Water Using Lithium Based Materials |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2002951962A0 (en) * | 2002-10-09 | 2002-10-24 | Bhp Billiton Innovation Pty Ltd | Electrolytic reduction of metal oxides |
AU2002952083A0 (en) | 2002-10-16 | 2002-10-31 | Bhp Billiton Innovation Pty Ltd | Minimising carbon transfer in an electrolytic cell |
US8152895B2 (en) * | 2003-04-23 | 2012-04-10 | Ut-Battelle, Llc | Production of magnesium metal |
EP2469969A1 (en) | 2010-12-24 | 2012-06-27 | Philip Morris Products S.A. | Reduced ceramic heating element |
KR101655143B1 (en) * | 2013-12-20 | 2016-09-07 | 현대자동차 주식회사 | Regeneration method of raw materials for hydrogen supply system of fuel cell |
CN109055985B (en) * | 2018-09-12 | 2019-09-27 | 郑州大学 | A kind of electrolytic oxidation magnesium molten salt system, preparation method and applications |
KR102004920B1 (en) * | 2019-01-28 | 2019-07-29 | 한국지질자원연구원 | Metal refining method by using liquid metal cathode |
CN110219021A (en) * | 2019-06-19 | 2019-09-10 | 李运雄 | A kind of closing down magnesium electrolysis bath and magnesium eletrolysis technique |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3951763A (en) * | 1973-06-28 | 1976-04-20 | Aluminum Company Of America | Aluminum smelting temperature selection |
US4455202A (en) * | 1982-08-02 | 1984-06-19 | Standard Oil Company (Indiana) | Electrolytic production of lithium metal |
US4973390A (en) * | 1988-07-11 | 1990-11-27 | Aluminum Company Of America | Process and apparatus for producing lithium from aluminum-lithium alloy scrap in a three-layered lithium transport cell |
US5378325A (en) * | 1991-09-17 | 1995-01-03 | Aluminum Company Of America | Process for low temperature electrolysis of metals in a chloride salt bath |
US5593566A (en) * | 1995-06-09 | 1997-01-14 | General Motors Corporation | Electrolytic production process for magnesium and its alloys |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2487386A1 (en) * | 1980-07-23 | 1982-01-29 | Pechiney Aluminium | METHOD AND APPARATUS FOR PRECISELY REGULATING THE INTRODUCTION RATE AND THE ALUMINUM CONTENT OF AN IGNATED ELECTROLYSIS TANK, AND APPLICATION TO THE PRODUCTION OF ALUMINUM |
BR8207776A (en) * | 1981-07-01 | 1983-05-31 | Diamond Shamrock Corp | ELECTRIC ALUMINUM PRODUCTION |
US4597839A (en) * | 1983-12-14 | 1986-07-01 | Atlantic Richfield Company | Method and apparatus for production of a metal from metallic oxide ore |
GB8707781D0 (en) * | 1987-04-01 | 1987-05-07 | Shell Int Research | Electrolytic production of metals |
US5279715A (en) * | 1991-09-17 | 1994-01-18 | Aluminum Company Of America | Process and apparatus for low temperature electrolysis of oxides |
JP2005510630A (en) * | 2001-11-22 | 2005-04-21 | キューアイティー−フェル エ チタン インク. | Method for electrowinning titanium metal or alloy from titanium oxide containing compound in liquid state |
-
2001
- 2001-04-10 AU AUPR4439A patent/AUPR443901A0/en not_active Abandoned
-
2002
- 2002-04-10 EP EP02713941A patent/EP1392890A4/en not_active Withdrawn
- 2002-04-10 CN CNA028100840A patent/CN1509346A/en active Pending
- 2002-04-10 CA CA002443953A patent/CA2443953A1/en not_active Abandoned
- 2002-04-10 JP JP2002581721A patent/JP2004523662A/en active Pending
- 2002-04-10 WO PCT/AU2002/000456 patent/WO2002083989A1/en active Application Filing
- 2002-04-10 US US10/474,746 patent/US20040237710A1/en not_active Abandoned
-
2003
- 2003-10-09 NO NO20034548A patent/NO20034548L/en not_active Application Discontinuation
- 2003-10-14 ZA ZA200307978A patent/ZA200307978B/en unknown
-
2007
- 2007-10-26 US US11/924,808 patent/US20080110764A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3951763A (en) * | 1973-06-28 | 1976-04-20 | Aluminum Company Of America | Aluminum smelting temperature selection |
US4455202A (en) * | 1982-08-02 | 1984-06-19 | Standard Oil Company (Indiana) | Electrolytic production of lithium metal |
US4973390A (en) * | 1988-07-11 | 1990-11-27 | Aluminum Company Of America | Process and apparatus for producing lithium from aluminum-lithium alloy scrap in a three-layered lithium transport cell |
US5378325A (en) * | 1991-09-17 | 1995-01-03 | Aluminum Company Of America | Process for low temperature electrolysis of metals in a chloride salt bath |
US5593566A (en) * | 1995-06-09 | 1997-01-14 | General Motors Corporation | Electrolytic production process for magnesium and its alloys |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100323253A1 (en) * | 2006-02-22 | 2010-12-23 | University Of Utah Resarch Foundation | Systems and Methods for Hydrogen Storage and Generation from Water Using Lithium Based Materials |
Also Published As
Publication number | Publication date |
---|---|
EP1392890A4 (en) | 2004-10-06 |
JP2004523662A (en) | 2004-08-05 |
NO20034548L (en) | 2003-12-01 |
CN1509346A (en) | 2004-06-30 |
EP1392890A1 (en) | 2004-03-03 |
WO2002083989A1 (en) | 2002-10-24 |
US20080110764A1 (en) | 2008-05-15 |
AUPR443901A0 (en) | 2001-05-17 |
CA2443953A1 (en) | 2002-10-24 |
ZA200307978B (en) | 2004-09-03 |
NO20034548D0 (en) | 2003-10-09 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: BHP BILLITON INNOVATION PTY LTD., AUSTRALIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STREZOV, LAZAR;RATCHEV, IVAN;OSBORN, STEVE;REEL/FRAME:015486/0061 Effective date: 20040326 |
|
AS | Assignment |
Owner name: BHP BILLITON INNOVATION PTY LTD., AUSTRALIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STREZOV, LAZAR;RATCHEV, IVAN;OSBORN, STEVE;REEL/FRAME:015691/0388 Effective date: 20040326 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |