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WO2007014422A1 - Reduction electrochimique d'oxydes metalliques - Google Patents

Reduction electrochimique d'oxydes metalliques Download PDF

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Publication number
WO2007014422A1
WO2007014422A1 PCT/AU2006/001088 AU2006001088W WO2007014422A1 WO 2007014422 A1 WO2007014422 A1 WO 2007014422A1 AU 2006001088 W AU2006001088 W AU 2006001088W WO 2007014422 A1 WO2007014422 A1 WO 2007014422A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrolyte
cao
concentration
titanium oxide
controlling
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.)
Ceased
Application number
PCT/AU2006/001088
Other languages
English (en)
Inventor
Ivan Ratchev
Rene Ignacio Olivares
Sergey Alexander Bliznyukov
Kannapar Mukunthan
Gregory David Rigby
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BHP Innovation Pty Ltd
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 AU2005904121A external-priority patent/AU2005904121A0/en
Application filed by BHP Billiton Innovation Pty Ltd filed Critical BHP Billiton Innovation Pty Ltd
Priority to EP06760944.6A priority Critical patent/EP1920087B1/fr
Priority to EA200800526A priority patent/EA014138B1/ru
Priority to AU2006275304A priority patent/AU2006275304B2/en
Publication of WO2007014422A1 publication Critical patent/WO2007014422A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • C25C3/26—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
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/14—Refining in the solid state
    • 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

Definitions

  • the present invention relates to electrochemical reduction of metal oxides .
  • the present invention relates particularly, although by no means exclusively, to electrochemical reduction of metal oxides in the form of powders and/or pellets in an electrolytic cell containing a molten electrolyte to produce reduced material, namely metal having a low oxygen concentration, typically no more than 0.2% by weight.
  • the present invention is concerned with controlling electrochemical reduction of metal oxides.
  • the present invention applies to situations in which the process is carried out on a batch basis, a continuous basis, and a semi-continuous basis.
  • the present invention was made during the course of a research project on electrochemical reduction of metal oxides carried out by the applicant.
  • the research project focussed on the reduction of titania (TiO 2 ) .
  • the CaCl 2 -based electrolyte used in the experiments was a commercially available source of CaCl 2 , _ o —
  • 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 laboratory electrolytic cells under a wide range of different operating parameters and conditions.
  • the applicant operated the laboratory electrolytic cells on a batch basis with titania in the form of pellets and larger solid blocks in the early part of the laboratory work and titania powder in the later part of the work.
  • the applicant also operated the laboratory electrolytic cells on a batch basis with other metal oxides.
  • Recent pilot plant work carried out by the applicant was carried out on a pilot plant electrolytic cell that was set up to operate initially on a continuous basis and subsequently on a batch basis.
  • the concentration of CaO in the electrolyte should be controlled by maintaining the concentration above a minimum CaO concentration and below a maximum CaO concentration in order to optimise operation of the process .
  • CaO and titania react spontaneously and form perovskite (CaTiO 3 ) .
  • the amount of CaO may decrease substantially as a consequence of the perovskite reaction.
  • An important physical characteristic is the surface area of titania in contact with electrolyte, particularly when this characteristic is considered in the context of a given mass of the electrolyte and a given mass of the titania.
  • the titania surface area for a given mass of titania is dependent on physical characteristics of the titania, such as powder/pellet shape and porosity.
  • the applicant also believes that the above- mentioned significance of the CaO concentration in a CaCl 2 - based electrolyte also applies to other alkali earth metal oxides , alkali metal oxides , and yttrium oxides . Specifically, the applicant believes that where one or more than one of the metal oxides is present in a CaCl 2 - based electrolyte, controlling the concentrations of the metal oxides within ranges is a means of optimising operation of an electrochemical reduction process for titanium oxide in a solid state in the electrolyte.
  • the metal oxides may be present as an impurity or impurites in the feed material used to produce the CaCl 2 - based electrolyte and/or by way of specific addition to the electrolyte.
  • a process for electrochemically reducing a titanium oxide in a solid state in an electrolytic cell that includes an anode, a cathode, a molten CaCl 2 -based electrolyte containing CaO, and titanium oxide feed material in contact with the molten electrolyte, which electrochemical process includes applying an electrical potential across the anode and the cathode and electrochemically reducing titanium oxide feed material in contact with the molten electrolyte and producing reduced material, and which process is characterised by controlling the process by controlling the concentration of CaO in the electrolyte.
  • the process includes controlling the concentration of CaO in the electrolyte by maintaining the concentration of CaO in the electrolyte between lower and upper concentration limits .
  • the maximum CaO concentration in the electrolyte is 0.5 wt . % .
  • the maximum CaO concentration in the electrolyte is 0.3 wt.%.
  • the minimum CaO concentration in the electrolyte is 0.005 wt.%.
  • the minimum CaO concentration in the electrolyte is 0.05 wt.%.
  • the minimum CaO concentration in the electrolyte is 0.1 wt.%.
  • the CaO concentration in the electrolyte is in the range of 0.1-0.3 wt.%.
  • the CaO concentration in the electrolyte is in the range of 0.15-0.25 wt.%.
  • the process includes controlling the concentration of CaO in the electrolyte by reference to the surface area of contact of the titanium oxide with the electrolyte .
  • the process includes controlling the concentration of CaO in the electrolyte by reference to the surface area of contact of the titanium oxide with the electrolyte when considered in the context of the mass of the electrolyte and the mass of the titanium oxide.
  • One practical option for controlling the CaO concentration in the electrolyte is to control the mass ratio of the electrolyte and the titanium oxide in the cell .
  • the process includes controlling the mass ratio of the electrolyte and titanium oxide in the cell to be at least 10:1 in situations where the initial CaO concentration is below 0.3, more preferably below 0.2 wt . % in the electrolyte and the titanium oxide is in a form of pellets and/or powders having a specific surface area of 0.1 to 100 m 2 /g of titanium oxide.
  • the process may include controlling the CaO concentration in the electrolyte by adding CaO to the electrolyte during the course of the process.
  • the process may include controlling the CaO concentration in the electrolyte by selecting an initial CaO concentration that is sufficiently high.
  • the electrochemical process may be carried out on any one of a batch basis, a semi-continuous basis, or a continuous basis .
  • the titanium oxide feed material is in a powder and/or a pellet form.
  • the titanium oxide feed material is titania .
  • the electrochemical reduction process includes applying a potential across the anode and the cathode that is above the decomposition potential of CaO and below the decomposition of CaCl2 •
  • the electrochemical reduction process may be carried out as a single stage or a multi-stage process .
  • a process for electrochemically reducing a titanium oxide in a solid state in an electrolytic cell that includes (a) an anode, (b) a cathode, (c) a molten CaCl 2 -based electrolyte containing any one or more than one metal oxide selected from the group including alkali earth metal oxides , alkali metal oxides, and yttrium oxides, and (d) a titanium oxide feed material in contact with the molten electrolyte, which electrochemical process includes applying an electrical potential across the anode and the cathode and electrochemically reducing titanium oxide feed material in contact with the molten electrolyte and producing reduced material, and which process is characterised by controlling the process by controlling the concentration of the selected metal oxide or metal oxides in the electrolyte .
  • the selected metal oxide is CaO.
  • the cell comprised a reaction vessel, a furnace, a crucible assembly, an electrode assembly, and a power supply.
  • the reaction vessel was manufactured from a high temperature stainless steel and had an internal diameter of 110mm and height of 430mm, and a water-cooled flange.
  • the vessel was contained within a resistance- heated furnace capable of reaching 1400 0 K.
  • a positioning pedestal within the vessel allowed for the crucible containing the molten salt to be properly fixed within the vessel .
  • a water-cooled lid was a critical feature of the reaction vessel and had provision for a viewing port which facilitated accurate positioning of the electrodes and the thermocouple within the molten salt bath.
  • the viewing port also allowed the surface of the molten salt to be monitored during the reaction.
  • Carbon monoxide and carbon dioxide are the main by-products of the electrochemical reduction process .
  • special care was taken in controlling the gas atmosphere .
  • a measured flow of high purity argon gas was passed through a furnace containing copper turnings at 873°K, then through a furnace containing magnesium flakes at 673 0 K before entering the vessel . After passing through the vessel, the gas stream was stripped of any chlorine- containing species and moisture and continuously analysed for CO and CO 2 .
  • a solid electrolyte based oxygen analyser monitored the partial pressure of O 2 in the off-gas immediately after the furnace.
  • the chemistry of the molten electrolyte was found to have a significant impact on the process operation. Consequently, the applicant ensured that the composition of the electrolyte at the start of a run was well controlled.
  • the electrolyte was prepared from analytical grade dihydrate, CaCl 2 .H 2 O obtained from AFS Chemicals. Typically, 68Og of molten salt were used in the experiments. Prior to melting, a dehydration step was carried out as follows .
  • the CaCl 2 .H 2 O was slowly heated under vacuum to 525K and kept at this temperature for at least 12 hours during which time the weight loss due to water removal was monitored. Once there was no more weight loss, the anhydrous salt was transferred from the vacuum oven into a platinum crucible and placed in a melting furnace . The salt was melted at 1275 0 K and kept at this temperature for 30 minutes to allow further removal of any residual water. The molten salt was then cast into a preheated steel mould, removed once solid, and transferred while hot to a drying oven held at 400K.
  • the titania pellets were prepared from 99.5% minimum purity rutile (Alfa Aesar) although occasionally other titania sources were used.
  • the titania pellets were prepared so that control of the total porosity and pore size was exercised by sintering at a predetermined temperature.
  • the concentration of CaO in the electrolyte was systematically increased up to 2.5 wt. %.
  • Figure 1 is a plot of cell current (in Amps) versus time (on seconds) for each of the above-mentioned experiments .
  • the Figure shows that there was a decrease in cell current over time with each of the CaO concentrations in the electrolyte.
  • the Figure also shows that the cell passed more current with increased concentrations of CaO in the electrolyte. This finding. Of itself, does not indicate that there was increased duction of titania at increased CaO concentrations .
  • Figure 2 is a plot of the concentration of oxygen in titanium in the reduced pellets versus the CaO concentration in the electrolyte at the end of the experimental runs of 4 hours .
  • the Figure shows that reduction of titania to titanium was inhibited as the concentration of CaO in the electrolyte increased.
  • the Figure shows that there were higher concentrations of oxygen in the titanium produced in the cell as the CaO concentrations in the electrolyte increased.
  • the Figure shows that the rate of reduction decreased as the concentration of CaO in the electrolyte increased.
  • Figures 1 and 2 indicate that significantly higher current consumption was required to achiev lower levels of reduction of titania at increased CaO concentrations.
  • operating at CaO concentrations of 0.5 wt.% or less produced high levels of reduction - to less than about 0.5 wt.% oxygen - with reasonable current consumption
  • Figure 3 is a plot of the amount of carbon removed from the anode in grams and the overall current efficiency versus the CaO concentration in the electrolyte at the end of the experimental runs of 4 hours .
  • the Figure shows that the amounts of electricity and carbon consumed in the process were proportionally higher as the concentration of CaO in the electrolyte increased.
  • the Figure shows that the current efficiency decreased as the concentration of CaO in the electrolyte increased.

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

Abstract

L'invention concerne un processus de réduction électrochimique d'un oxyde de titane à l'état solide dans une cellule électrolytique qui contient une anode, une cathode, un électrolyte fondu à base de CaCl2 et à teneur en CaO ainsi qu'une substance de base d'oxyde de titane en contact avec l'électrolyte fondu. Ce processus est caractérisé en ce que la régulation dudit processus s'effectue par une régulation de la concentration de CaO dans l'électrolyte.
PCT/AU2006/001088 2005-08-01 2006-08-01 Reduction electrochimique d'oxydes metalliques Ceased WO2007014422A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP06760944.6A EP1920087B1 (fr) 2005-08-01 2006-08-01 Reduction electrochimique d'oxyde de titane
EA200800526A EA014138B1 (ru) 2005-08-01 2006-08-01 Электрохимическое восстановление оксидов металлов
AU2006275304A AU2006275304B2 (en) 2005-08-01 2006-08-01 Electrochemical reduction of metal oxides

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2005904121A AU2005904121A0 (en) 2005-08-01 Electrochemical reduction of metal oxides
AU2005904121 2005-08-01

Publications (1)

Publication Number Publication Date
WO2007014422A1 true WO2007014422A1 (fr) 2007-02-08

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PCT/AU2006/001088 Ceased WO2007014422A1 (fr) 2005-08-01 2006-08-01 Reduction electrochimique d'oxydes metalliques

Country Status (3)

Country Link
EP (1) EP1920087B1 (fr)
EA (1) EA014138B1 (fr)
WO (1) WO2007014422A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8129414B2 (en) 2006-06-19 2012-03-06 Adeboye Adejare Non-competitive NMDA receptor antagonists
WO2013171463A1 (fr) * 2012-05-16 2013-11-21 Metalysis Limited Procédé, appareil et produit électrolytique
CN106947874A (zh) * 2017-04-18 2017-07-14 北京科技大学 一种两步法制备高纯钛的方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003002785A1 (fr) * 2001-06-29 2003-01-09 Bhp Billiton Innovation Pty Ltd Reduction d'oxydes metalliques dans une cellule electrolytique
WO2003076690A1 (fr) * 2002-03-13 2003-09-18 Bhp Billiton Innovation Pty Ltd Reduction d'oxydes metalliques dans une cellule electrolytique
WO2003076692A1 (fr) * 2002-03-13 2003-09-18 Bhp Billiton Innovation Pty Ltd Minimisation du transfert de carbone dans une cellule electrolytique
WO2004035873A1 (fr) * 2002-10-16 2004-04-29 Bhp Billiton Innovation Pty Ltd Procede pour reduire au minimum le transfert de carbone dans une cellule electrolytique

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003129268A (ja) * 2001-10-17 2003-05-08 Katsutoshi Ono 金属チタンの精錬方法及び精錬装置
AUPS107102A0 (en) * 2002-03-13 2002-04-11 Bhp Billiton Innovation Pty Ltd Electrolytic reduction of metal oxides
JP2004360025A (ja) * 2003-06-05 2004-12-24 Sumitomo Titanium Corp 直接電解法による金属チタンの製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003002785A1 (fr) * 2001-06-29 2003-01-09 Bhp Billiton Innovation Pty Ltd Reduction d'oxydes metalliques dans une cellule electrolytique
WO2003076690A1 (fr) * 2002-03-13 2003-09-18 Bhp Billiton Innovation Pty Ltd Reduction d'oxydes metalliques dans une cellule electrolytique
WO2003076692A1 (fr) * 2002-03-13 2003-09-18 Bhp Billiton Innovation Pty Ltd Minimisation du transfert de carbone dans une cellule electrolytique
WO2004035873A1 (fr) * 2002-10-16 2004-04-29 Bhp Billiton Innovation Pty Ltd Procede pour reduire au minimum le transfert de carbone dans une cellule electrolytique

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8129414B2 (en) 2006-06-19 2012-03-06 Adeboye Adejare Non-competitive NMDA receptor antagonists
WO2013171463A1 (fr) * 2012-05-16 2013-11-21 Metalysis Limited Procédé, appareil et produit électrolytique
AU2013261598B2 (en) * 2012-05-16 2017-07-06 Metalysis Limited Electrolytic method, apparatus and product
US10066307B2 (en) 2012-05-16 2018-09-04 Metalysis Limited Electrolytic method, apparatus and product
EA037329B1 (ru) * 2012-05-16 2021-03-12 Металисиз Лимитед Электролитический способ извлечения кислорода
CN106947874A (zh) * 2017-04-18 2017-07-14 北京科技大学 一种两步法制备高纯钛的方法
CN106947874B (zh) * 2017-04-18 2018-11-27 北京科技大学 一种两步法制备高纯钛的方法

Also Published As

Publication number Publication date
EP1920087A1 (fr) 2008-05-14
EP1920087A4 (fr) 2011-07-27
EP1920087B1 (fr) 2017-03-22
EA200800526A1 (ru) 2008-08-29
EA014138B1 (ru) 2010-10-29

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