US20050092129A1 - Minimising carbon transfer in an electrolytic cell - Google Patents

Minimising carbon transfer in an electrolytic cell Download PDF

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Publication number
US20050092129A1
US20050092129A1 US10/939,001 US93900104A US2005092129A1 US 20050092129 A1 US20050092129 A1 US 20050092129A1 US 93900104 A US93900104 A US 93900104A US 2005092129 A1 US2005092129 A1 US 2005092129A1
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US
United States
Prior art keywords
cell
cathode
potential
carbon
anode
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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
Application number
US10/939,001
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English (en)
Inventor
Les Strezov
Ivan Ratchev
Steve Osborn
Sergey Bliznyukov
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BILLITON INNOVATION Pty Ltd
BHP Billiton Innovation Pty Ltd
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BHP Billiton Innovation Pty Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BHP Billiton Innovation Pty Ltd filed Critical BHP Billiton Innovation Pty Ltd
Assigned to BILLITON INNOVATION PTY LTD. reassignment BILLITON INNOVATION PTY LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: STREZOV, LES, BLIZNYUKOV, SERGEY ALEXANDER, OSBORN, STEVE, RATCHEV, IVAN
Publication of US20050092129A1 publication Critical patent/US20050092129A1/en
Abandoned legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/005Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells of cells for the electrolysis of melts
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00Obtaining refractory metals
    • C22B34/10Obtaining titanium, zirconium or hafnium
    • C22B34/12Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/129Obtaining 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

Definitions

  • the present invention relates to to reduction of metal oxides in a solid state in an electrolytic cell.
  • the present invention was made during the course of an on-going research project on solid state reduction of titania (TiO2) carried out by the applicant.
  • the CaCl 2 -based electrolyte was a commercially available source of CaCl 2 , namely calcium chloride dihydrate, that partially decomposed on heating and produced CaO.
  • the applicant operated the electrolytic cell at a potential above the decomposition potential of CaO and below the decomposition potential of CaCl 2 .
  • the experimental work was carried out using a CaCl 2 -based electrolyte at a cell potential below the decomposition potential of CaCl 2 .
  • the applicant believes that the initial deposition of Ca metal on the cathode was due to the presence of Ca ++ cations and O ⁇ anions derived from CaO in the electrolyte.
  • the decomposition potential of CaO is less than the decomposition potential of CaCl 2 .
  • the cell operation is dependent, at least during the early stages of cell operation, on decomposition of CaO, with Ca ++ cations migrating to the cathode and depositing as Ca metal and O ⁇ anions migrating to the anode and forming CO and/or CO 2 (in a situation in which the anode is a graphite anode).
  • the applicant also believes that at later stages of the cell operation part of the Ca metal that deposited on the cathode was deposited directly on partially deoxidised titanium and thereafter participated in chemical reduction of titanium.
  • the applicant also believes that the O ⁇ anions, once extracted from the titania, migrated to the anode and reacted with anode carbon and produced CO and/or CO 2 (and in some instances CaO) and released electrons that facilitated electrolytic deposition of Ca metal on the cathode.
  • Carbon in the titanium is an undesirable contaminant.
  • carbon transfer was partially responsible for low energy efficiency of the cell. Both problems are significant barriers to commercialisation of electrolytic reduction technology.
  • the applicant carried out experimental work to identify the mechanism for carbon transfer and to determine how to minimise carbon transfer and/or to minimise the adverse effects of carbon transfer.
  • the present invention provides an electrolytic cell for reducing a metal oxide in a solid state, which electrolytic cell includes an anode formed from carbon, a cathode formed at least in part from the metal oxide, and a membrane that is permeable to oxygen anions and is impermeable to carbon in ionic and non-ionic forms positioned between the cathode and the anode to thereby prevent migration of carbon to the cathode.
  • the anode is formed from graphite.
  • the membrane may be formed from any suitable material.
  • the membrane is formed from a solid electrolyte.
  • One suitable solid electrolyte tested by the applicant is yttria stabilised zirconia.
  • the cathode also includes an electrical conductor.
  • the present invention also provides a method of reducing a metal oxide in a solid state using the above-described electrolytic cell.
  • the method includes a step of operating the cell at a potential that is above a decomposition potential of at least one of the constituents of the electrolyte so that there are cations of a metal other than that of the metal oxide in the electrolyte.
  • the metal oxide is a titanium oxide, such as titania
  • the electrolyte be a CaCl 2 -based electrolyte that includes CaO as one of constituents.
  • the cell potential be above the decomposition potential for CaO.
  • the cell potential be below the decomposition potential for CaCl 2 .
  • the cell potential be less than or equal to 3.0 V.
  • the cell potential be below 2.5 V.
  • the cell potential be below 2.0 V.
  • the cell potential be above 1.5 V.
  • the CaCl 2 -based electrolyte may be a commercially available source of CaCl 2 , such as calcium chloride dihydrate, that partially decomposes on heating and produces CaO or otherwise includes CaO.
  • the CaCl 2 -based electrolyte may include CaCl 2 and CaO that are added separately or pre-mixed to form the electrolyte.
  • the cell included a high density graphite crucible that formed the anode of the cell, a pool of molten CaCl 2 electrolyte in the crucible, and a cathode that included solid titania.
  • the solid titania was in the form of titania pellets connected to a lower end of a Kanthal or stainless steel electrically conductive wire.
  • the ionic barrier was in the form of a yttria stabilised zirconia membrane positioned between the anode and the cathode, thereby dividing the cell into an outer anode chamber and an inner cathode chamber.
  • FIG. 1 is a schematic of the cell set-up for the experiment.
  • the cell included a graphite crucible 3 that formed the anode, a pool 19 of molten CaCl 2 electrolyte in the crucible, titania pellets 5 and an electrically conductive wire 7 that formed the cathode immersed in the electrolyte, and a yttria stabilised zirconia membrane 9 immersed in the electrolyte between the anode and the cathode.
  • the cell was located in a resistance furnace 11 heated to a temperature to maintain the electrolyte in a molten state.
  • the experimental set-up also included gas monitoring, cleaning, and analysis equipment.
  • the cell was operated at an applied potential of 3V for a period of 35 hours, during which time there was continuous monitoring of the off-gas from the furnace. At the conclusion of the experiment, the cell was cooled and the solidified electrolyte, the membrane, the anode and the cathode were analysed.
  • FIG. 2 is a summary of the results of the experiment.
  • FIG. 2 shows measured voltage, current, CO and CO 2 composition of the off-gas for the experiment.
  • the invention is not so limited and extends to electrolytic reduction of other titanium oxides and to oxides of other metals and alloys.
  • Examples of other potentially important meals are aluminium, silicon, germanium, hafnium, magnesium, and molybdenum.
  • suitable electrolytes will be salts and oxides that are soluble in salts.
  • a potentially suitable electrolyte is BaCl 2 .

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Inert Electrodes (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
US10/939,001 2002-03-13 2004-09-10 Minimising carbon transfer in an electrolytic cell Abandoned US20050092129A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AUPS1170 2002-03-13
AUPS1170A AUPS117002A0 (en) 2002-03-13 2002-03-13 Minimising carbon transfer in an electrolytic cell
PCT/AU2003/000305 WO2003076692A1 (fr) 2002-03-13 2003-03-13 Minimisation du transfert de carbone dans une cellule electrolytique
WOPCT/AU03/00305 2003-03-13

Publications (1)

Publication Number Publication Date
US20050092129A1 true US20050092129A1 (en) 2005-05-05

Family

ID=3834768

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/939,001 Abandoned US20050092129A1 (en) 2002-03-13 2004-09-10 Minimising carbon transfer in an electrolytic cell

Country Status (12)

Country Link
US (1) US20050092129A1 (fr)
EP (1) EP1483431B1 (fr)
JP (1) JP2005520046A (fr)
CN (1) CN1650052A (fr)
AT (1) ATE367461T1 (fr)
AU (1) AUPS117002A0 (fr)
CA (1) CA2479050A1 (fr)
DE (1) DE60314999D1 (fr)
MX (1) MXPA04008886A (fr)
RU (1) RU2302482C2 (fr)
WO (1) WO2003076692A1 (fr)
ZA (1) ZA200407433B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060180462A1 (en) * 2002-10-16 2006-08-17 Les Strezov Minimising carbon transfer in an electrolytic cell
US20090045070A1 (en) * 2006-02-06 2009-02-19 Becker Aaron J Cathode for electrolytic production of titanium and other metal powders

Families Citing this family (3)

* Cited by examiner, † Cited by third party
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
RU2370575C2 (ru) * 2004-06-28 2009-10-20 Би Эйч Пи БИЛЛИТОН ИННОВЕЙШН ПТИ ЛТД Получение титана
WO2007014422A1 (fr) * 2005-08-01 2007-02-08 Bhp Billiton Innovation Pty Ltd Reduction electrochimique d'oxydes metalliques

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6187168B1 (en) * 1998-10-06 2001-02-13 Aluminum Company Of America Electrolysis in a cell having a solid oxide ion conductor
US20030047463A1 (en) * 2000-02-22 2003-03-13 Ward-Close Charles M. Electrolytic reduction of metal oxides such as titanium dioxide and process applications
US6540902B1 (en) * 2001-09-05 2003-04-01 The United States Of America As Represented By The United States Department Of Energy Direct electrochemical reduction of metal-oxides
US20040159559A1 (en) * 1998-06-05 2004-08-19 Fray Derek John Removal of oxygen from metal oxides and solid solutions by electrolysis in a fused salt

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07113158B2 (ja) * 1984-04-14 1995-12-06 新日本製鐵株式会社 溶鋼の清浄化方法
JPH03115592A (ja) * 1989-09-28 1991-05-16 Osaka Titanium Co Ltd 溶融塩電解槽
US5670270A (en) * 1995-11-16 1997-09-23 The Dow Chemical Company Electrode structure for solid state electrochemical devices
GB2359564B (en) * 2000-02-22 2004-09-29 Secr Defence Improvements in the electrolytic reduction of metal oxides
JP4089944B2 (ja) * 2001-11-30 2008-05-28 財団法人電力中央研究所 電解還元装置および方法
EA007046B1 (ru) * 2002-03-13 2006-06-30 Би Эйч Пи БИЛЛИТОН ИННОВЕЙШН ПТИ ЛТД. Восстановление оксидов металлов в электролизере
JP4252531B2 (ja) * 2004-12-15 2009-04-08 株式会社大阪チタニウムテクノロジーズ 金属製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040159559A1 (en) * 1998-06-05 2004-08-19 Fray Derek John Removal of oxygen from metal oxides and solid solutions by electrolysis in a fused salt
US6187168B1 (en) * 1998-10-06 2001-02-13 Aluminum Company Of America Electrolysis in a cell having a solid oxide ion conductor
US20030047463A1 (en) * 2000-02-22 2003-03-13 Ward-Close Charles M. Electrolytic reduction of metal oxides such as titanium dioxide and process applications
US20030047462A1 (en) * 2000-02-22 2003-03-13 Ward-Close Charles M Method of manufacture for ferro-titanium and other metal alloys electrolytic reduction
US20030057101A1 (en) * 2000-02-22 2003-03-27 Ward Close Charles M Method for the manufacture of metal foams by electrolytic reduction of porous oxidic preforms
US6540902B1 (en) * 2001-09-05 2003-04-01 The United States Of America As Represented By The United States Department Of Energy Direct electrochemical reduction of metal-oxides

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060180462A1 (en) * 2002-10-16 2006-08-17 Les Strezov Minimising carbon transfer in an electrolytic cell
US7628904B2 (en) * 2002-10-16 2009-12-08 Metalysis Limited Minimising carbon transfer in an electrolytic cell
US20090045070A1 (en) * 2006-02-06 2009-02-19 Becker Aaron J Cathode for electrolytic production of titanium and other metal powders

Also Published As

Publication number Publication date
WO2003076692A1 (fr) 2003-09-18
ZA200407433B (en) 2005-10-10
AUPS117002A0 (en) 2002-04-18
RU2004130453A (ru) 2005-06-10
JP2005520046A (ja) 2005-07-07
EP1483431A4 (fr) 2006-06-28
EP1483431B1 (fr) 2007-07-18
MXPA04008886A (es) 2004-11-26
ATE367461T1 (de) 2007-08-15
CA2479050A1 (fr) 2003-09-18
RU2302482C2 (ru) 2007-07-10
EP1483431A1 (fr) 2004-12-08
DE60314999D1 (de) 2007-08-30
CN1650052A (zh) 2005-08-03

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Owner name: BILLITON INNOVATION PTY LTD., AUSTRALIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STREZOV, LES;RATCHEV, IVAN;OSBORN, STEVE;AND OTHERS;REEL/FRAME:016158/0232;SIGNING DATES FROM 20041124 TO 20041202

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION