WO2003076690A1 - Reduction of metal oxides in an electrolytic cell - Google Patents

Reduction of metal oxides in an electrolytic cell Download PDF

Info

Publication number
WO2003076690A1
WO2003076690A1 PCT/AU2003/000306 AU0300306W WO03076690A1 WO 2003076690 A1 WO2003076690 A1 WO 2003076690A1 AU 0300306 W AU0300306 W AU 0300306W WO 03076690 A1 WO03076690 A1 WO 03076690A1
Authority
WO
WIPO (PCT)
Prior art keywords
metal
electrolyte
cathode
metal oxide
potential
Prior art date
Application number
PCT/AU2003/000306
Other languages
French (fr)
Inventor
Les Strezov
Ivan Ratchev
Steve Osborn
Original Assignee
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
Priority claimed from AUPS1071A external-priority patent/AUPS107102A0/en
Priority claimed from AUPS3049A external-priority patent/AUPS304902A0/en
Priority to MXPA04008887A priority Critical patent/MXPA04008887A/en
Priority to BRPI0308384-5A priority patent/BR0308384B1/en
Priority to KR1020047014399A priority patent/KR101038701B1/en
Priority to EP03743767A priority patent/EP1492905A4/en
Priority to EA200401203A priority patent/EA007046B1/en
Priority to AU2003209826A priority patent/AU2003209826B2/en
Application filed by Bhp Billiton Innovation Pty Ltd filed Critical Bhp Billiton Innovation Pty Ltd
Priority to NZ531467A priority patent/NZ531467A/en
Priority to APAP/P/2004/003141A priority patent/AP1616A/en
Priority to CA2479048A priority patent/CA2479048C/en
Priority to CN038092735A priority patent/CN1650051B/en
Priority to JP2003574882A priority patent/JP4658479B2/en
Publication of WO2003076690A1 publication Critical patent/WO2003076690A1/en
Priority to NO20043857A priority patent/NO340277B1/en

Links

Classifications

    • 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
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/26Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
    • C25C3/28Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium of titanium
    • 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
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B5/00General methods of reducing to metals
    • C22B5/02Dry methods smelting of sulfides or formation of mattes
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00Electrolytic production, recovery or refining of metals by electrolysis of melts
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25CPROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/18Electrolytes

Definitions

  • the present invention relates 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 (Ti0 2 ) carried out by the applicant.
  • One application is the direct production of a metal from a metal oxide.
  • the "discovery” is the realisation that an electrolytic cell can be used to ionise oxygen contained in a metal oxide so that the oxygen dissolves in an electrolyte.
  • the Cambridge International application discloses that when a suitable potential is applied to an electrolytic cell with a metal oxide as a cathode, a reaction occurs whereby oxygen is ionised and is subsequently able to dissolve in the electrolyte of the cell.
  • the allowed claims of the European patent application inter alia define a method of electrolytically reducing a metal oxide (such as titania) that includes operating an electrolytic cell at a potential at an electrode formed from the metal oxide that is lower than the deposition potential of cations in the electrolyte at a surface of the electrode.
  • a metal oxide such as titania
  • the Cambridge European patent application does not define what is meant by deposition potential and does not include any specific examples that provide values of the deposition potential for particular cations .
  • page 5 of the submissions state that:
  • the present invention provides a method of reducing a metal oxide in a solid state in an electrolytic cell, which electrolytic cell includes an anode, a cathode, a molten electrolyte, the electrolyte includes cations of a metal that is capable of chemically reducing the metal oxide, and the metal oxide in a solid state immersed in the electrolyte, and which method includes a step of operating the cell at a potential that is above a potential at which cations of the metal that is capable of chemically reducing the metal oxide can deposit as the metal on the cathode, whereby the metal chemically reduces the metal oxide.
  • the experimental work carried out by the applicant produced evidence of Ca metal dissolved in the electrolyte.
  • the applicant believes that, at least during the early stages of operation of the cell, the Ca metal was the result of electrodeposition of Ca ++ cations as Ca metal on electrically conductive sections of the cathode.
  • the experimental work was carried out using a CaCl 2 -based electrolyte at a cell potential below the decomposition potential of CaCl 2 .
  • 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 C0 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 0 "" anions, once extracted from the titania, migrated to the anode and reacted with anode carbon and produced CO and/or C0 2 (and in some instances CaO) and released electrons that facilitated electrolytic deposition of Ca metal on the cathode.
  • the cathode is formed at least in part from the metal oxide.
  • the method includes operating the cell at the potential that is above the potential at which cations of the metal that is capable of chemically reducing the metal oxide deposit as the metal on the cathode so that the metal deposits on the cathode.
  • the metal deposited on the cathode is soluble in the electrolyte and can dissolve in the electrolyte and thereby migrate to the vicinity of the metal oxide .
  • the electrolyte be a CaCl 2 -based electrolyte that includes CaO as one of the constituents of the electrolyte.
  • the present invention does not require the addition of substantial amounts of CaO to the electrolyte.
  • the cell potential be above a potential at which Ca metal can deposit on the cathode, i.e. at a potential that is above the decomposition potential of CaO.
  • the decomposition potential of CaO can vary over a considerable range depending on factors such as the composition of the anode, the electrolyte temperature and electrolyte composition.
  • the cell potential be below the potential at which CI " anions can deposit on the anode and form chlorine gas, i.e. the decomposition potential of CaCl 2 .
  • the decomposition potential of CaCl 2 can vary over a considerable range depending on factors such as the composition of the anode, the electrolyte temperature and electrolyte composition.
  • the cell potential be between 1.3 and 3.5V.
  • 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.
  • anode be graphite or an inert anode .
  • Carbon in the titanium is an undesirable contaminant.
  • carbon transfer was partially responsible for low energy efficiency of the cell. Both problems could present significant barriers to commercialisation of electrolytic reduction technology.
  • the dominant mechanism of carbon transfer is electrochemical rather than erosion and that one way of minimising carbon transfer and therefore contamination of titanium produced at the cathode by electrochemical reduction of titania is to position a membrane that is permeable to oxygen anions and is impermeable to carbon in ionic and non-ionic forms between the cathode and the anode and thereby prevent migration of carbon to the cathode.
  • the electrolytic cell includes 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 membrane may be formed from any suitable material .
  • the membrane is formed from a solid electrolyte.
  • One solid electrolyte tested by the applicant is yttria stabilised zirconia.
  • an electrolytic cell as described above and operating in accordance with the above described method.
  • the electrolytic cell is shown in Figure 1.
  • the electrochemical cell included a graphite crucible equipped with a graphite lid.
  • the crucible was used as the cell anode.
  • a stainless steel rod was used to secure electrical contact between a d/c power supply and the crucible.
  • the cell cathode consisted of Kanthal or platinum wire connected at one end to the power supply and Ti0 2 pellets suspended from the other end of the wire.
  • An alumina tube was used as an insulator around the cathode.
  • the cell electrolyte was a commercially available source of CaCl 2 , namely calcium chloride dihydrate, that partially decomposed on heating at the operating temperature of the cell and produced CaO.
  • a thermocouple was immersed in the electrolyte in close proximity to the pellets.
  • pellets Two types were used. One type was slip-cast and the other type was pressed. Both types of pellets were made from analytical grade Ti0 2 powder. Both types of pellets were sintered in air at 850°C. One pressed and one slip-cast pellet were used in the experiment .
  • the cell was positioned in a furnace and the experiment was conducted at 950°C. Voltages up to 3V were applied between the crucible wall and the Kanthal or platinum wire. The voltage of 3V is below the potential at which CI " anions can deposit on the anode at that temperature. In addition, the voltage of 3V is above the decomposition potential of CaO and below the decomposition potential of CaCl 2 .
  • the power-supply maintained a constant voltage throughout the experiment.
  • the voltage and resulting cell current were logged using LabVIEW (TM) data acquisition software.
  • the constant voltage (3V) used in the experiment produced an initial current of approximately 1.2A. A continuous drop in the current was observed during the initial 2 hours. After that a gradual increase in the current up to 1A was observed.
  • the invention is not so limited and extends to reduction of other titanium oxides and to oxides of other metals and alloys.
  • examples of other potentially important metals are aluminium, silicon, germanium, zirconium, hafnium, magnesium and molybdenum.
  • suitable electrolytes will be salts and oxides that are soluble in salts.
  • suitable electrolyte is BaCl 2 .

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Electrolytic Production Of Metals (AREA)

Abstract

A method of reducing a metal oxide, such as titania in a solid state in an electrolytic cell is disclosed. The electrolytic cell includes an anode, a cathode, and a molten electrolyte. The electrolyte includes cations of a metal that is capable of chemically reducing the metal oxide. The metal oxide in a solid state is immersed in the electrolyte. The method includes a step of operating the cell at a potential that is above a potential at which cations of the metal that is capable of chemically reducing the metal oxide deposit as the metal on the cathode, whereby the metal chemically reduces the metal oxide.

Description

REDUCTION OF METAL OXIDES IN AN ELECTROLYTIC CELL
The present invention relates 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 (Ti02) carried out by the applicant.
During the course of the research project the applicant carried out experimental work on the reduction of titania using an electrolytic cell that included a graphite crucible that formed an anode of the cell, a pool of molten CaCl2-based electrolyte in the crucible/ and a range of cathodes that included solid titania.
One objective of the experimental work was to reproduce the results reported in International application PCT/GB99/01781 (publication no. 099/64638) in the name of Cambridge University Technical Services
Limited and in technical papers published by the inventors of that International application.
The Cambridge International application discloses two potential applications of .a "discovery" in the field of metallurgical electrochemistry.
One application is the direct production of a metal from a metal oxide.
In the context of this application, the "discovery" is the realisation that an electrolytic cell can be used to ionise oxygen contained in a metal oxide so that the oxygen dissolves in an electrolyte. The Cambridge International application discloses that when a suitable potential is applied to an electrolytic cell with a metal oxide as a cathode, a reaction occurs whereby oxygen is ionised and is subsequently able to dissolve in the electrolyte of the cell.
European patent application 9995507.1 derived from the Cambridge International application has been allowed by the European Patent Office.
The allowed claims of the European patent application inter alia define a method of electrolytically reducing a metal oxide (such as titania) that includes operating an electrolytic cell at a potential at an electrode formed from the metal oxide that is lower than the deposition potential of cations in the electrolyte at a surface of the electrode.
The Cambridge European patent application does not define what is meant by deposition potential and does not include any specific examples that provide values of the deposition potential for particular cations .
However, submissions dated 2 October 2001 to the European Patent Office by the Cambridge patent attorneys, which pre-dated the lodgement of the claims that were ultimately allowed, indicate that they believe that the decomposition potential of an electrolyte is the deposition potential of a cation in the electrolyte.
Specifically, page 5 of the submissions state that:
"The second advantage described above is achieved in part through carrying out the claimed invention below the decomposition potential of the electrolyte. If higher potentials are used then, as noted in DI and D2, the cation in the electrolyte deposits on the metal or semi - metal compound. In the example of DI, this leads to calcium deposition and therefore consumption of this reactive metaI............Duringr operation of the method, the electrolytic cation is not deposited on the cathode".
Contrary to the findings of Cambridge, the experimental work carried out by the applicant has established that it is essential that the electrolytic cell be operated at a potential that is above the potential at which Ca++ cations in the electrolyte can deposit as Ca metal on the cathode.
Accordingly, the present invention provides a method of reducing a metal oxide in a solid state in an electrolytic cell, which electrolytic cell includes an anode, a cathode, a molten electrolyte, the electrolyte includes cations of a metal that is capable of chemically reducing the metal oxide, and the metal oxide in a solid state immersed in the electrolyte, and which method includes a step of operating the cell at a potential that is above a potential at which cations of the metal that is capable of chemically reducing the metal oxide can deposit as the metal on the cathode, whereby the metal chemically reduces the metal oxide.
The applicant does not have a clear understanding of the electrolytic cell mechanism at this stage.
Nevertheless, whilst not wishing to be bound by the comments in this and the following paragraphs, the applicant offers the following comments by way of an outline of a possible cell mechanism.
The experimental work carried out by the applicant produced evidence of Ca metal dissolved in the electrolyte. The applicant believes that, at least during the early stages of operation of the cell, the Ca metal was the result of electrodeposition of Ca++ cations as Ca metal on electrically conductive sections of the cathode. The experimental work was carried out using a CaCl2-based electrolyte at a cell potential below the decomposition potential of CaCl2. 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 CaCl2. In this cell mechanism 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 C02 (in a situation in which the anode is a graphite anode) .
The applicant believes that the Ca metal that deposited on electrically conductive sections of the cathode was deposited predominantly as a separate phase in the early stages of cell operation and thereafter dissolved in the electrolyte and migrated to the vicinity of the titania in the cathode and participated in chemical reduction of titania.
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 0""anions, once extracted from the titania, migrated to the anode and reacted with anode carbon and produced CO and/or C02 (and in some instances CaO) and released electrons that facilitated electrolytic deposition of Ca metal on the cathode.
Preferably the cathode is formed at least in part from the metal oxide.
Preferably the method includes operating the cell at the potential that is above the potential at which cations of the metal that is capable of chemically reducing the metal oxide deposit as the metal on the cathode so that the metal deposits on the cathode.
Preferably the metal deposited on the cathode is soluble in the electrolyte and can dissolve in the electrolyte and thereby migrate to the vicinity of the metal oxide .
In a situation in which the metal oxide is a titanium oxide, such as titania, it is preferred that the electrolyte be a CaCl2-based electrolyte that includes CaO as one of the constituents of the electrolyte. In this context, it is noted that the present invention does not require the addition of substantial amounts of CaO to the electrolyte.
In such a situation it is preferred that the cell potential be above a potential at which Ca metal can deposit on the cathode, i.e. at a potential that is above the decomposition potential of CaO.
The decomposition potential of CaO can vary over a considerable range depending on factors such as the composition of the anode, the electrolyte temperature and electrolyte composition.
In a cell containing CaO saturated CaCl2 at 1373K (1100 °C) and a graphite anode this would require a minimum cell potential of 1.34V.
It is also preferred that the cell potential be below the potential at which CI" anions can deposit on the anode and form chlorine gas, i.e. the decomposition potential of CaCl2.
In a cell containing CaO saturated CaCl2 at 1373K (1100 °C) and a graphite anode this would require that the cell potential be less than 3.5V.
The decomposition potential of CaCl2 can vary over a considerable range depending on factors such as the composition of the anode, the electrolyte temperature and electrolyte composition.
For example, a salt containing 80% CaCl2 and 20% KC1 at a temperature of 900K (657°C), decomposes to Ca (metal) and Cl2 (gas) above 3.4V and a salt containing 100% CaCl2 at 1373K (1100 °C) decomposes at 3.0V.
In general terms, in a cell containing CaO-CaCl2 salt (not saturated) at a temperature in the range of 600- 1100°C and a graphite anode it is preferred that the cell potential be between 1.3 and 3.5V.
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-mixed to form the electrolyte.
It is preferred that the anode be graphite or an inert anode .
The applicant found in the experimental work that there were relatively significant amounts of carbon transferred from the graphite anode to the electrolyte and to a lesser extent, to the titanium produced at the cathode under a wide range of cell operating conditions.
Carbon in the titanium is an undesirable contaminant. In addition, carbon transfer was partially responsible for low energy efficiency of the cell. Both problems could present significant barriers to commercialisation of electrolytic reduction technology.
The applicant also found that the dominant mechanism of carbon transfer is electrochemical rather than erosion and that one way of minimising carbon transfer and therefore contamination of titanium produced at the cathode by electrochemical reduction of titania is to position a membrane that is permeable to oxygen anions and is impermeable to carbon in ionic and non-ionic forms between the cathode and the anode and thereby prevent migration of carbon to the cathode.
Accordingly, in order to minimise contamination of titanium produced at the cathode resulting from carbon transfer, it is preferred that the electrolytic cell includes 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 membrane may be formed from any suitable material .
Preferably the membrane is formed from a solid electrolyte.
One solid electrolyte tested by the applicant is yttria stabilised zirconia.
According to the present invention there is also provided an electrolytic cell as described above and operating in accordance with the above described method.
The present invention is described further with reference to the following example.
I. Experimental Method and Electrolytic Cell
The electrolytic cell is shown in Figure 1.
With reference to Figure 1, the electrochemical cell included a graphite crucible equipped with a graphite lid. The crucible was used as the cell anode. A stainless steel rod was used to secure electrical contact between a d/c power supply and the crucible. The cell cathode consisted of Kanthal or platinum wire connected at one end to the power supply and Ti02 pellets suspended from the other end of the wire. An alumina tube was used as an insulator around the cathode. The cell electrolyte was a commercially available source of CaCl2, namely calcium chloride dihydrate, that partially decomposed on heating at the operating temperature of the cell and produced CaO. A thermocouple was immersed in the electrolyte in close proximity to the pellets.
Two types of pellets were used. One type was slip-cast and the other type was pressed. Both types of pellets were made from analytical grade Ti02 powder. Both types of pellets were sintered in air at 850°C. One pressed and one slip-cast pellet were used in the experiment .
The cell was positioned in a furnace and the experiment was conducted at 950°C. Voltages up to 3V were applied between the crucible wall and the Kanthal or platinum wire. The voltage of 3V is below the potential at which CI" anions can deposit on the anode at that temperature. In addition, the voltage of 3V is above the decomposition potential of CaO and below the decomposition potential of CaCl2.
The power-supply maintained a constant voltage throughout the experiment. The voltage and resulting cell current were logged using LabVIEW (TM) data acquisition software.
At the end of the experiment the cell was removed from the furnace and quenched in water. The solid CaCl2 was dissolved by water and the two pellets were recovered.
II. Experimental Results
With reference to Figures 2 and 3, the constant voltage (3V) used in the experiment produced an initial current of approximately 1.2A. A continuous drop in the current was observed during the initial 2 hours. After that a gradual increase in the current up to 1A was observed.
SEM images of the cross-sections of the two recovered pellets are shown in Figures 4 and 5. The SEM images indicate the presence of metallic titanium in both pellets, thereby establishing that the method successfully electrochemically reduced titania.
The presence of virtually pure metallic titanium in both pellets was confirmed by EPMA analysis. The analysis also showed areas of partially reduced titania. The EPMA results are shown in Figures 6 and 7.
Carbon was detected at various locations within the pellets and its content varied up to 18wt%. Many modifications may be made to the present invention as described above without departing from the the spirit and scope of the invention.
By way of example, whilst the above description of the invention focuses on reduction of titania, the invention is not so limited and extends to reduction of other titanium oxides and to oxides of other metals and alloys. Examples of other potentially important metals are aluminium, silicon, germanium, zirconium, hafnium, magnesium and molybdenum.
Furthermore, whilst the above description focuses on CaCl2-based electrolyte, the invention is not so limited and extends to any other suitable electrolytes (and mixtures of electrolytes) . Generally, suitable electrolytes will be salts and oxides that are soluble in salts. One example of a potentially suitable electrolyte is BaCl2.

Claims

CLAIMS :
1. A method of reducing a metal oxide in a solid state in an electrolytic cell, which electrolytic cell includes an anode, a cathode, a molten electrolyte, the electrolyte includes cations of a metal that is capable of chemically reducing the metal oxide, and the metal oxide in a solid state is immersed in the electrolyte, and which method includes a step of operating the cell at a potential that is above a potential at which cations of the metal that is capable of chemically reducing the metal oxide can deposit as the metal on the cathode, whereby the metal chemically reduces the metal oxide .
2. The method defined in claim 1 includes operating the cell that is above the potential at which cations of the metal that is capable of chemically reducing the metal oxide deposit as the metal on the cathode so that the metal deposits on the cathode.
3. The method defined in claim 2 wherein the metal deposited on the cathode is soluble in the electrolyte and can dissolve in the electrolyte and thereby migrate to the vicinity of the metal oxide.
4. The method defined in any one of the preceding claims wherein the metal oxide is a titanium oxide, the electrolyte is a CaCl2-based electrolyte that includes CaO as one of the constituents of the electrolyte, and the cell potential is above a potential at which Ca metal can deposit on the cathode.
5. The method defined in claim 4 wherein the cell potential is below the decomposition potential for
CaCl2 to minimise forming Cl2 gas at the anode.
6. The method defined in claim 4 or claim 5 wherein the cell potential is less than or equal to 3.5V in a cell operating with the electrolyte at 600-1100°C.
7. The method defined in any one of claims 4 to 6 wherein the cell potential is at least 1.3V in a cell operating with the electrolyte at 600-1100°C.
8. The method defined in any one of claims 4 to 7 wherein the CaCl2-based electrolyte is a commercially available source of CaCl2 that forms CaO on heating or otherwise includes CaO.
9. The method defined in any one of claims 4 to 7 wherein the CaCl2-based electrolyte includes CaCl2 and
CaO that are added separately or pre-mixed to form the electrolyte.
10. The method defined in any one of the preceding claims wherein the anode is graphite.
11. The method defined in any one of the preceding claims wherein the anode is graphite and the electrolytic cell includes 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.
12. The method defined in any one of the preceding claims wherein the cathode is formed at least in part from the metal oxide .
13. An electrolytic cell reducing a metal oxide in a solid state, which electrolytic cell includes an anode, a cathode, a molten electrolyte, which electrolyte includes cations of a metal that is capable of chemically reducing the metal oxide, and a metal oxide in a solid state immersed in the electrolyte, and which electrolytic cell operates at a potential that is above a potential at which cations of the metal that is capable of chemically reducing the metal oxide deposit as the metal on the cathode, whereby the metal chemically reduces the metal oxide .
14. The cell defined in claim 12 wherein the cathode is formed at least in part from the metal oxide.
PCT/AU2003/000306 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell WO2003076690A1 (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
CN038092735A CN1650051B (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell
JP2003574882A JP4658479B2 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in electrolytic cells
NZ531467A NZ531467A (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell operating above the threshold potential
KR1020047014399A KR101038701B1 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an elecrolytic cell
EP03743767A EP1492905A4 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell
EA200401203A EA007046B1 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell
AU2003209826A AU2003209826B2 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell
MXPA04008887A MXPA04008887A (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell.
BRPI0308384-5A BR0308384B1 (en) 2002-03-13 2003-03-13 Method of reducing solid state metal oxide in an electrolytic cell; and electrolytic cell that reduces a solid state metal oxide through this method
APAP/P/2004/003141A AP1616A (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell.
CA2479048A CA2479048C (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell
NO20043857A NO340277B1 (en) 2002-03-13 2004-09-15 A method of reducing a solid metal oxide in an electrolysis cell.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AUPS1071 2002-03-13
AUPS1071A AUPS107102A0 (en) 2002-03-13 2002-03-13 Electrolytic reduction of metal oxides
AUPS3049 2002-06-19
AUPS3049A AUPS304902A0 (en) 2002-06-19 2002-06-19 Reduction of metal oxides in an electrolytic cell

Publications (1)

Publication Number Publication Date
WO2003076690A1 true WO2003076690A1 (en) 2003-09-18

Family

ID=27805836

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2003/000306 WO2003076690A1 (en) 2002-03-13 2003-03-13 Reduction of metal oxides in an electrolytic cell

Country Status (12)

Country Link
EP (2) EP2770086A3 (en)
JP (1) JP4658479B2 (en)
KR (2) KR20110025237A (en)
CN (1) CN1650051B (en)
BR (1) BR0308384B1 (en)
CA (1) CA2479048C (en)
EA (1) EA007046B1 (en)
MX (1) MXPA04008887A (en)
NO (1) NO340277B1 (en)
NZ (1) NZ531467A (en)
WO (1) WO2003076690A1 (en)
ZA (1) ZA200407434B (en)

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004018735A1 (en) * 2002-08-23 2004-03-04 Cambridge University Technical Services Limited Electrochemical method and apparatus
WO2004033760A2 (en) * 2002-10-09 2004-04-22 Bhp Billiton Innovation Pty Ltd Electrochemical reduction of metal oxides
WO2004035873A1 (en) * 2002-10-16 2004-04-29 Bhp Billiton Innovation Pty Ltd Minimising carbon transfer in an electrolytic cell
JP2005105373A (en) * 2003-09-30 2005-04-21 Nippon Light Metal Co Ltd Reduction method for metal oxide and reduction device for metal oxide
JP2005105374A (en) * 2003-09-30 2005-04-21 Nippon Light Metal Co Ltd Reduction method for metal oxide and reduction device for metal oxide
WO2006000025A1 (en) * 2004-06-28 2006-01-05 Bhp Billiton Innovation Pty Ltd Production of titanium
WO2007014422A1 (en) * 2005-08-01 2007-02-08 Bhp Billiton Innovation Pty Ltd Electrochemical reduction of metal oxides
JP2007529631A (en) * 2004-03-22 2007-10-25 ビーエイチピー ビリトン イノベーション プロプライアタリー リミテッド Electrochemical reduction of metal oxides
EP2032727A1 (en) * 2006-06-14 2009-03-11 Norsk Titanium Metals AS Method, apparatus and means for production of metals in a molten salt electrolyte
WO2010092358A1 (en) 2009-02-13 2010-08-19 Metalysis Limited A method for producing metal powders
WO2012066299A1 (en) 2010-11-18 2012-05-24 Metalysis Limited Method and system for electrolytically reducing a solid feedstock
WO2012066298A2 (en) 2010-11-18 2012-05-24 Metalysis Limited Electrolysis apparatus and method
WO2012066297A2 (en) 2010-11-18 2012-05-24 Metalysis Limited Electrolysis apparatus
WO2012104640A2 (en) 2011-02-04 2012-08-09 Metalysis Limited Electrolysis method, apparatus and product
RU2466216C1 (en) * 2011-06-17 2012-11-10 Государственное образовательное учреждение высшего профессионального образования "Национальный исследовательский Томский политехнический университет" Method for obtaining metallic titanium by means of electrolysis
WO2013050772A2 (en) 2011-10-04 2013-04-11 Metalysis Limited Electrolytic production of powder
JP2013532385A (en) * 2010-06-26 2013-08-15 フレイ,デレク,ジョン A method for texturing silicon surfaces to produce black silicon for photovoltaic applications
WO2014102223A1 (en) 2012-12-24 2014-07-03 Metalysis Limited Method and apparatus for producing metal by electrolytic reduction
WO2015198052A1 (en) 2014-06-26 2015-12-30 Metalysis Limited Method and apparatus for electrolytic reduction of a feedstock comprising oxygen and a first metal
WO2017081160A1 (en) 2015-11-10 2017-05-18 Stichting Energieonderzoek Centrum Nederland Additive manufacturing of metal objects
WO2017141044A1 (en) * 2016-02-17 2017-08-24 Metalysis Limited Methods of making graphene materials
WO2018051106A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Method of Producing a Composite Material
WO2018051104A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Composite powder and method of producing composite powder
WO2018051105A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Method of producing a powder
WO2018208155A1 (en) 2017-05-10 2018-11-15 Admatec Europe B.V. Additive manufacturing of metal objects
WO2020055252A2 (en) 2018-09-12 2020-03-19 Admatec Europe B.V. Three-dimensional object and manufacturing method thereof

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPS117002A0 (en) * 2002-03-13 2002-04-18 Bhp Billiton Innovation Pty Ltd Minimising carbon transfer in an electrolytic cell
CN100532653C (en) * 2006-11-03 2009-08-26 西北有色金属研究院 Method for extracting titanium from electrolyzed molten salt
GB0714021D0 (en) * 2007-07-18 2007-08-29 Green Metals Ltd Improvements in anode materials
KR101526298B1 (en) * 2013-04-22 2015-06-10 서울대학교산학협력단 Method of manufacturing a titanium oxide electrode, system for generating oxidative reactive species, system for generating chlorine, dye-sensitized solar cell, and electric double-layer capacitor including the same
KR101740424B1 (en) 2015-08-18 2017-05-26 충남대학교산학협력단 Fabrication Method of metal titanium using Ilmenite ore
CN109763146B (en) * 2019-03-27 2021-03-26 贵州省过程工业技术研究中心 Preparation method of titanium-based composite material anode for aluminum electrolysis

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999064638A1 (en) * 1998-06-05 1999-12-16 Cambridge University Technical Services Limited Removal of oxygen from metal oxides and solid solutions by electrolysis in a fused salt
US6074545A (en) * 1997-02-04 2000-06-13 Cathingots Limited Process for the electrolytic production of metals
GB2359564A (en) * 2000-02-22 2001-08-29 Secr Defence Electrolytic reduction of metal oxides
WO2002083993A1 (en) * 2001-04-10 2002-10-24 Bhp Billiton Innovation Pty Ltd Electrolytic reduction of metal oxides
WO2003002785A1 (en) * 2001-06-29 2003-01-09 Bhp Billiton Innovation Pty Ltd Reduction of metal oxides in an electrolytic cell
WO2003016594A1 (en) * 2001-08-16 2003-02-27 Bhp Billiton Innovation Pty Ltd Method of manufacturing titanium and titanium alloy products

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS322357B1 (en) * 1954-12-29 1957-04-18
JP2003129268A (en) * 2001-10-17 2003-05-08 Katsutoshi Ono Method for smelting metallic titanium and smelter therefor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6074545A (en) * 1997-02-04 2000-06-13 Cathingots Limited Process for the electrolytic production of metals
WO1999064638A1 (en) * 1998-06-05 1999-12-16 Cambridge University Technical Services Limited Removal of oxygen from metal oxides and solid solutions by electrolysis in a fused salt
GB2359564A (en) * 2000-02-22 2001-08-29 Secr Defence Electrolytic reduction of metal oxides
WO2002083993A1 (en) * 2001-04-10 2002-10-24 Bhp Billiton Innovation Pty Ltd Electrolytic reduction of metal oxides
WO2003002785A1 (en) * 2001-06-29 2003-01-09 Bhp Billiton Innovation Pty Ltd Reduction of metal oxides in an electrolytic cell
WO2003016594A1 (en) * 2001-08-16 2003-02-27 Bhp Billiton Innovation Pty Ltd Method of manufacturing titanium and titanium alloy products

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1492905A4 *

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004018735A1 (en) * 2002-08-23 2004-03-04 Cambridge University Technical Services Limited Electrochemical method and apparatus
WO2004033760A3 (en) * 2002-10-09 2007-11-29 Bhp Billiton Innovation Pty Electrochemical reduction of metal oxides
WO2004033760A2 (en) * 2002-10-09 2004-04-22 Bhp Billiton Innovation Pty Ltd Electrochemical reduction of metal oxides
WO2004035873A1 (en) * 2002-10-16 2004-04-29 Bhp Billiton Innovation Pty Ltd Minimising carbon transfer in an electrolytic cell
US7628904B2 (en) 2002-10-16 2009-12-08 Metalysis Limited Minimising carbon transfer in an electrolytic cell
JP2005105373A (en) * 2003-09-30 2005-04-21 Nippon Light Metal Co Ltd Reduction method for metal oxide and reduction device for metal oxide
JP2005105374A (en) * 2003-09-30 2005-04-21 Nippon Light Metal Co Ltd Reduction method for metal oxide and reduction device for metal oxide
JP4502617B2 (en) * 2003-09-30 2010-07-14 日本軽金属株式会社 Metal oxide reduction method and metal oxide reduction apparatus
JP4513297B2 (en) * 2003-09-30 2010-07-28 日本軽金属株式会社 Metal oxide reduction method and metal oxide reduction apparatus
JP2007529631A (en) * 2004-03-22 2007-10-25 ビーエイチピー ビリトン イノベーション プロプライアタリー リミテッド Electrochemical reduction of metal oxides
WO2006000025A1 (en) * 2004-06-28 2006-01-05 Bhp Billiton Innovation Pty Ltd Production of titanium
AU2005256146B2 (en) * 2004-06-28 2010-11-25 Metalysis Limited Production of titanium
WO2007014422A1 (en) * 2005-08-01 2007-02-08 Bhp Billiton Innovation Pty Ltd Electrochemical reduction of metal oxides
EA014138B1 (en) * 2005-08-01 2010-10-29 БиЭйчПи БИЛЛИТОН ИННОВЕЙШН ПТИ ЛТД. Electrochemical reduction of metal oxides
EP2032727A4 (en) * 2006-06-14 2012-09-12 Norsk Titanium Technology As Method, apparatus and means for production of metals in a molten salt electrolyte
EP2032727A1 (en) * 2006-06-14 2009-03-11 Norsk Titanium Metals AS Method, apparatus and means for production of metals in a molten salt electrolyte
EA020381B1 (en) * 2009-02-13 2014-10-30 Металисиз Лимитед A method for producing metal powders
WO2010092358A1 (en) 2009-02-13 2010-08-19 Metalysis Limited A method for producing metal powders
US9579725B2 (en) 2009-02-13 2017-02-28 Metalysis Limited Method for producing metal powders
US9393623B2 (en) 2009-02-13 2016-07-19 Metalysis Limited Method for producing metal powders
JP2013532385A (en) * 2010-06-26 2013-08-15 フレイ,デレク,ジョン A method for texturing silicon surfaces to produce black silicon for photovoltaic applications
WO2012066299A1 (en) 2010-11-18 2012-05-24 Metalysis Limited Method and system for electrolytically reducing a solid feedstock
WO2012066298A2 (en) 2010-11-18 2012-05-24 Metalysis Limited Electrolysis apparatus and method
WO2012066297A2 (en) 2010-11-18 2012-05-24 Metalysis Limited Electrolysis apparatus
WO2012104640A2 (en) 2011-02-04 2012-08-09 Metalysis Limited Electrolysis method, apparatus and product
RU2466216C1 (en) * 2011-06-17 2012-11-10 Государственное образовательное учреждение высшего профессионального образования "Национальный исследовательский Томский политехнический университет" Method for obtaining metallic titanium by means of electrolysis
WO2013050772A2 (en) 2011-10-04 2013-04-11 Metalysis Limited Electrolytic production of powder
WO2014102223A1 (en) 2012-12-24 2014-07-03 Metalysis Limited Method and apparatus for producing metal by electrolytic reduction
WO2015198052A1 (en) 2014-06-26 2015-12-30 Metalysis Limited Method and apparatus for electrolytic reduction of a feedstock comprising oxygen and a first metal
WO2017081160A1 (en) 2015-11-10 2017-05-18 Stichting Energieonderzoek Centrum Nederland Additive manufacturing of metal objects
EA037801B1 (en) * 2016-02-17 2021-05-24 Металисиз Лимитед Method of making graphene materials
WO2017141044A1 (en) * 2016-02-17 2017-08-24 Metalysis Limited Methods of making graphene materials
AU2017220569B2 (en) * 2016-02-17 2022-06-23 Metalysis Limited Methods of making graphene materials
US11072862B2 (en) 2016-02-17 2021-07-27 Metalysis Limited Methods of making graphene materials
WO2018051104A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Composite powder and method of producing composite powder
WO2018051105A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Method of producing a powder
WO2018051106A1 (en) 2016-09-14 2018-03-22 Metalysis Limited Method of Producing a Composite Material
WO2018208155A1 (en) 2017-05-10 2018-11-15 Admatec Europe B.V. Additive manufacturing of metal objects
US11772157B2 (en) 2017-05-10 2023-10-03 Admatec Europe B.V. Additive manufacturing of metal objects
WO2020055252A2 (en) 2018-09-12 2020-03-19 Admatec Europe B.V. Three-dimensional object and manufacturing method thereof

Also Published As

Publication number Publication date
NZ531467A (en) 2007-06-29
KR101038701B1 (en) 2011-06-02
MXPA04008887A (en) 2004-11-26
KR20110025237A (en) 2011-03-09
EP1492905A1 (en) 2005-01-05
JP2005520045A (en) 2005-07-07
CA2479048C (en) 2012-07-10
CA2479048A1 (en) 2003-09-18
EP1492905A4 (en) 2006-06-28
EA007046B1 (en) 2006-06-30
EP2770086A3 (en) 2014-10-29
EP2770086A2 (en) 2014-08-27
BR0308384B1 (en) 2014-02-04
KR20040111408A (en) 2004-12-31
BR0308384A (en) 2005-01-25
JP4658479B2 (en) 2011-03-23
ZA200407434B (en) 2006-05-31
CN1650051B (en) 2011-02-23
EA200401203A1 (en) 2005-06-30
CN1650051A (en) 2005-08-03
NO340277B1 (en) 2017-03-27
NO20043857L (en) 2004-12-08

Similar Documents

Publication Publication Date Title
CA2479048C (en) Reduction of metal oxides in an electrolytic cell
US6663763B2 (en) Reduction of metal oxides in an electrolytic cell
Mohandas et al. FFC Cambridge process and removal of oxygen from metal-oxygen systems by molten salt electrolysis: an overview
AU758931C (en) Removal of oxygen from metal oxides and solid solutions by electrolysis in a fused salt
US20060191799A1 (en) Electrochemical reduction of metal oxides
US20100006448A1 (en) Method, apparatus and means for production of metals in a molten salt electrolyte
JP2007016293A (en) Method for producing metal by suspension electrolysis
US20040084323A1 (en) Extraction of metals
US7628904B2 (en) Minimising carbon transfer in an electrolytic cell
CN100532653C (en) Method for extracting titanium from electrolyzed molten salt
AU2003209826B2 (en) Reduction of metal oxides in an electrolytic cell
EP1483431B1 (en) Minimising carbon transfer in an electrolytic cell
AU2002231464B2 (en) Extraction of metals
CN114016083A (en) Method for regenerating alkali metal reducing agent in process of preparing metal by thermally reducing metal oxide with alkali metal
AU2003266842A1 (en) Electrochemical reduction of metal oxides
AU2003269600A1 (en) Minimising carbon transfer in an electrolytic cell
AU2002231464A1 (en) Extraction of metals
AU2003209825A1 (en) Minimising carbon transfer in an electrolytic cell

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PH PL PT RO RU SC SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 531467

Country of ref document: NZ

WWE Wipo information: entry into national phase

Ref document number: 2003209826

Country of ref document: AU

WWE Wipo information: entry into national phase

Ref document number: 2003574882

Country of ref document: JP

Ref document number: 1020047014399

Country of ref document: KR

Ref document number: 2479048

Country of ref document: CA

Ref document number: PA/a/2004/008887

Country of ref document: MX

WWE Wipo information: entry into national phase

Ref document number: 2003743767

Country of ref document: EP

Ref document number: 2727/DELNP/2004

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2004/07434

Country of ref document: ZA

Ref document number: 200407434

Country of ref document: ZA

WWE Wipo information: entry into national phase

Ref document number: 200401203

Country of ref document: EA

WWE Wipo information: entry into national phase

Ref document number: 20038092735

Country of ref document: CN

WWP Wipo information: published in national office

Ref document number: 1020047014399

Country of ref document: KR

WWP Wipo information: published in national office

Ref document number: 2003743767

Country of ref document: EP