WO2008101283A1 - Réduction électrochimique d'oxydes métalliques - Google Patents

Réduction électrochimique d'oxydes métalliques Download PDF

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Publication number
WO2008101283A1
WO2008101283A1 PCT/AU2008/000220 AU2008000220W WO2008101283A1 WO 2008101283 A1 WO2008101283 A1 WO 2008101283A1 AU 2008000220 W AU2008000220 W AU 2008000220W WO 2008101283 A1 WO2008101283 A1 WO 2008101283A1
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WO
WIPO (PCT)
Prior art keywords
cell
cathodes
cathode
anodes
anode
Prior art date
Application number
PCT/AU2008/000220
Other languages
English (en)
Inventor
Gregory David Rigby
Ivan Ratchev
Andrew Arthur Shook
Original Assignee
Metalysis Limited
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 AU2007900858A external-priority patent/AU2007900858A0/en
Application filed by Metalysis Limited filed Critical Metalysis Limited
Publication of WO2008101283A1 publication Critical patent/WO2008101283A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/129—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining metallic titanium from titanium compounds by dissociation, e.g. thermic dissociation of titanium tetraiodide, or by electrolysis or with the use of an electric arc
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/06—Operating or servicing
    • 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

Definitions

  • the present invention relates to electrochemical reduction of metal oxides in a solid state.
  • the present invention relates particularly, although by no means exclusively, to electrochemical reduction of metal oxides , such as titanium oxides , in any suitable solid state form in an electrolytic cell containing a molten electrolyte to produce a reduced material .
  • the reduced material is titanium having a low oxygen concentration, typically no more than 0.2% by weight.
  • 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 titanium oxides in the from of titania (TiO 2 ) .
  • 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 cathodes formed at least in part from 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 .
  • One result of the research project is a process for electrochemically reducing a metal oxide, such as a titanium oxide, in a solid state in an electrolytic cell that includes a molten bath of a CaCl 2 -based electrolyte containing CaO, an anode at least partially immersed in the electrolyte, and a cathode formed at least in part from the metal oxide and at least partially immersed in the electrolyte with the metal oxide contacting the electrolyte, which electrochemical process includes applying an electrical potential across the anode and the cathode that is above the decomposition potential of CaO and electrochemically reducing the metal oxide in contact with the molten electrolyte and producing reduced material.
  • the reduced material is titanium having no more than 0.2% by weight oxygen.
  • the applicant has considered the issue of scaling up the laboratory and pilot plant cells to a commercial scale electrochemical cell for carrying out the above- described electrochemical process .
  • the present invention is based on a realisation that a viable commercial scale electrochemical cell for carrying out an electrochemical process for reducing a metal oxide such as a titanium oxide in a solid state includes a plurality of cathodes that are formed at least in part from the metal oxide and can be removed from the cell and replaced by other such cathodes as the process continues to operate in the cell and thereby continues to reduce the metal oxide in the cell .
  • an electrochemical cell for carrying out an electrochemical process for reducing a metal oxide such as a titanium oxide in a solid state
  • which cell includes a cell chamber that contains a molten bath of an electrolyte, a plurality of anodes extending into the cell chamber and at least partially immersed in the electrolyte, and a plurality of cathodes formed at least in part from the metal oxide and extending into the cell chamber and at least partially immersed in the electrolyte with the metal oxide contacting the electrolyte, and with the cathodes being replaceable cathodes in that the cathodes can be removed from the cell chamber as required and replaced by other such cathodes during operation of the electrochemical process in the cell .
  • each cathode is retained in the cell in an operative position for a time period required to reduce the metal oxide of the cathode to a required extent, the cathode is then removed from the cell chamber and thereafter processed as required to separate metal from the cathode, and a replacement cathode formed at least in part from the metal oxide is inserted into the cell chamber in place of the removed cathode while the process continues to operate in the cell .
  • This sequence of steps is repeated for each replacement cathode while the process continues to operate in the cell .
  • the anodes are also replaceable anodes in that the anodes can be removed from the cell chamber and replaced by other such anodes while the process is operating in the cell.
  • the cell is a sealed cell to minimise air infiltration into the electrolyte in the cell chamber.
  • the cell includes a lid for the cell chamber which can close the cell chamber with an air-tight seal.
  • the lid includes a plurality of openings for allowing removal of existing cathodes from the cell chamber and insertion of replacement cathodes into the cell chamber.
  • the lid includes a plurality of openings for allowing removal of existing anodes from the cell chamber and insertion of replacement anodes into the cell chamber .
  • the openings and the anodes and the cathodes are formed so that there are air-tight seals when the anodes and the cathodes are positioned to extend through the openings in the lid in operative positions in the cell chamber.
  • the cell includes an apparatus for purging air from the cell chamber with a gas that is inert with respect to the reduced material produced in the cell at the operating temperature of the cell .
  • the inert gas is argon or helium.
  • the purge apparatus is arranged to purge the cell chamber via the openings in the lid.
  • the cell chamber may be internally heated, self- heated or externally heated to maintain the electrolyte in a molten state. Typically, it is preferred that the electrolyte be heated to a temperature in a range of 940- 1100 0 C.
  • the term "internally heated” is understood herein to mean that the cell chamber is heated with one or more heating means extending into the electrolyte in the cell chamber .
  • self-heated is understood herein to mean that the cell chamber is heated by resistance heating within the cell chamber.
  • the pilot plant work has found that it may be possible to maintain the electrolyte temperature in the cell chamber by internal (rather than external) heating or by self-heating. This is a potentially significant finding because external heating is not as practical an option as internal heating or self-heating.
  • a cell chamber must be made from materials that allow heat transfer and this constraint places limitations on operating temperature limits for the cell .
  • the cell chamber is internally heated or self-heated.
  • the cell chamber be self-heated.
  • the cell chamber may be any suitable shape and size.
  • the cell chamber may be a rectilinear shape with a base and parallel sides and parallel ends extending upwardly from the base.
  • the rectilinear-shaped cell chamber is 12-18 m, preferably 15 m, long and 1-3 m, preferably 2 m, wide.
  • the anodes and the cathodes may be any suitable shape and size.
  • the cell may include any suitable arrangement of the anodes and the cathodes in the cell chamber.
  • the optimum spacing of the anodes and the cathodes in a cell chamber of any given shape and size is governed by a number of factors including, by way of example, optimising current efficiency and controlling self-heating caused by resistance heating in the cell chamber .
  • the cell includes a plurality of pairs of the anodes and the cathodes arranged in the cell chamber whereby the metal oxide of the cathode of each anode/cathode pair is exposed to substantially the same reduction conditions .
  • the anode/cathode pair includes (a) an assembly of a line of spaced-apart downwardly extending anode rods and (b) an assembly of a line of a plurality of cathode elements, such as disks or pellets, adjacent the anode assembly.
  • each anode/cathode pair extends across the cell chamber from one side to the other side of the cell chamber and is supported on the sides of the cell chamber.
  • the metal oxide forms exposed surfaces of the cathodes.
  • the anode/cathode pair includes an anode and a cathode that are in the form of plates .
  • the plate anodes and the plate cathodes extend across the cell chamber from one side to the other side of the cell chamber and are supported on the sides of the cell chamber.
  • the anode/cathode pairs are arranged in side-by side parallel relationship in the cell chamber, with the plate anodes and the plate cathodes alternating in the cell so that the plate anodes are adjacent the plate cathodes and vice versa.
  • the surface-to-surface spacing of the plate anode and the plate cathode in each anode/cathode pair is in a range of 10-100 mm.
  • anode/cathode surface-to- surface spacing is 30-80 mm.
  • the anode/cathode surface-to-surface spacing is 50 mm.
  • the metal oxide forms exposed surfaces of the cathodes .
  • the metal oxide of the cathodes forms opposite sides of the plates .
  • each plate cathode includes an assembly of an electrically conductive plate and the metal oxide on both surfaces of the plate.
  • the electrically conductive plate may be a solid plate .
  • the electrically conductive plate may be a mesh.
  • the cell includes a plurality of anode/cathode modules that can be removed from the cell chamber and replaced with a replacement cell module, with each anode/cathode module including a plurality of the anodes and a plurality of the cathodes .
  • each anode/cathode module includes a support member that supports the anodes and the cathodes and forms a sealed section of the lid of the cell chamber .
  • each anode/cathode module includes a support member and a plurality of the plate anodes extending from the support member as a series of parallel , spaced apart anodes .
  • each anode/cathode module further includes a plurality of cathode plates positioned in gaps between adjacent anode plates and arranged to be separately removable from the module and replaced with replacement cathode plates.
  • each anode/cathode module includes an upper section that has a plurality of openings that allow insertion and removal of the cathode plates into gaps between adjacent anode plates of the module .
  • the openings in the support member of each anode/cathode module and the cathode plates are shaped and sized so that the cathode plates close the openings when the cathodes are positioned in an operative position in the cell, and thereby form a sealed section of a lid of the cell chamber.
  • the cell includes a busbar assembly that electrically connects the anodes and the cathodes to a source of electrical power.
  • anodes and the cathodes are connected together in a parallel electrical connection.
  • the anodes are formed from graphite.
  • the metal oxide is a titanium oxide, such as titania.
  • the metal oxide may be in any suitable form.
  • the metal oxide may be in the form of powders , pellets formed by agglomerating powders into pellet shapes, or other products formed by other processes.
  • the pellets may be disc-shaped.
  • the other products may be foamed metal oxide blocks .
  • the other products may be honeycomb-shaped products that include a series of interconnected walls that define a plurality of passages for the electrolyte to penetrate the structure to contact internal exposed surfaces of the products .
  • the electrolyte is a salt.
  • the electrolyte is CaCl 2 -based electrolyte containing CaO.
  • a plant for producing a metal such as titanium having no more than 0.2% by weight oxygen from a metal oxide such as a titanium oxide that includes a plurality of the above-described electrochemical cell.
  • a process for electrochemically reducing a metal oxide such as a titanium oxide in a solid state in the above-described electrolytic cell which electrochemical process includes applying an electrical potential across the anodes and the cathodes of the cell that is above the decomposition potential of a component in the molten electrolyte in the cell and electrochemically reducing the metal oxide in contact with the electrolyte and producing reduced material, and periodically removing the cathodes from the cell chamber and inserting replacement cathodes into the cell chamber while the process continues to operate in the cell .
  • the process includes removing no more than 30%, more preferably no more than 20%, of the cathodes from the cell chamber at any point in time.
  • the process includes timing the removal of the cathodes and the insertion of the replacement cathodes into the cell chamber to even out power consumption in the cell over a cell operating period.
  • the process includes removing the anodes from the cell chamber and inserting the replacement anodes into the cell chamber while the process continues to operate in the cell .
  • the process includes timing the removal of the anodes and the insertion of the replacement anodes into the cell chamber to even out power consumption in the cell over a cell operating period.
  • the process includes processing the removed cathodes to recover reduced material from the cathode .
  • the electrolyte is CaCl 2 -based electrolyte containing CaO and the process includes applying an electrical potential across the anodes and the cathodes of the cell that is above the decomposition potential of CaO in the molten electrolyte.
  • the reduced material is titanium having no more than 0.2% by weight oxygen.
  • Figure 1 is a partially sectional, end view of one embodiment of an electrochemical cell in accordance with the present invention.
  • Figure 2 is a top plan view of the anode/cathode cell module of the cell shown in Figure 1 ;
  • Figure 3 is a cross-section of the cell module shown in Figure 2 along the line 3-3 in Figure 2 ;
  • Figure 4 is a side elevation of the anode/cathode module shown in Figures 1-3 with the cathode plates of the module removed for clarity;
  • Figure 5 is a cross-section along the line 5-5 of
  • Figure 6 is a side elevation of a cathode plate of the anode/cathode module shown in Figures 1-5;
  • Figure 7 is an end view of the cathode plate shown in Figure 6;
  • Figure 8 is a partially cut-away, diagrammatic view of the cell chamber shown in Figure 1 with a plurality of the anode/cathode module shown in Figures 2-7 positioned in the cell chamber, with one cathode plate shown in a raised position to illustrate removal/insertion from the cell chamber ;
  • Figure 9 is an enlarged view of the right-side end of the Figure 8 arrangement;
  • Figure 10 is a perspective view of the anode/cathode module shown in Figures 2-7;
  • Figure 11 is a perspective view of another, although not the only other, embodiment of an electrochemical cell in accordance with the present invention, with only one anode/cathode module positioned in the cell for clarity;
  • Figure 12 is an enlarged view of the anodes and the cathode of the anode/cathode module shown in Figure 11;
  • Figure 13 is a perspective view identical to that of Figure 12 but with one anode removed for clarity;
  • Figure 14 is a front elevation of a part of the cathode of the anode/cathode module shown in Figures 11 to 13, with one cathode element of the cathode shown properly and the other cathode elements shown in outline for clarity;
  • Figure 15 is a side elevation of the part of the cathode shown in Figure 14 along the line 15-15;
  • Figure 16 is an enlarged front view of the cathode element shown in Figures 11-15.
  • Figure 1 shows a transverse cross-section of one embodiment of an electrochemical cell (generally identified by the numeral 3) in accordance with the present invention located in an electrochemical plant (only partly shown) .
  • the electrochemical cell 3 is one of a substantial number of such cells 3 in a commercial electrochemical plant that produces a metal (such as titanium) by electrochemical reduction of a metal oxide (such as a titanium oxide, for example titania) in the cells .
  • a metal such as titanium
  • a metal oxide such as a titanium oxide, for example titania
  • the cells 3 may be arranged, by way of example, along the lines of the cells in an aluminium plant or a copper electro-winning plant.
  • the electrochemical cell 3 includes (a) a cell chamber (generally identified by the numeral 41) , (b) a molten bath of a salt electrolyte, such as CaCl 2 -based electrolyte containing CaO, in the cell chamber 41 at a temperature of the order of 940-1100 0 C, (c) a plurality of pairs of anodes and cathodes extending into the cell chamber 41 and at least partially immersed in the electrolyte, with the cathodes being formed at least in part form the metal oxide, and (d) an apparatus (not shown) for purging air from the cell chamber 41.
  • a salt electrolyte such as CaCl 2 -based electrolyte containing CaO
  • the electrochemical cell 3 also includes a busbar assembly for supplying electricity from a remote power source (not shown) to the anodes and the cathodes to apply a potential between the anodes and the cathodes that is above the decomposition potential of CaO and thereby facilitate electrochemical reduction of the metal oxide.
  • the busbar assembly includes (a) a pair of busbars 11a, lib extending parallel to and outboard of the side walls 7 of the cell and (b) a plurality of "fingers" 13 extending inwardly from the busbars 11a, lib through the side walls 7 into the cell chamber 41 and electrically connecting the power supply to the anodes and the cathodes in the cell.
  • the electrochemical plant includes an anode/cathode handling apparatus for (a) removing the anodes and the cathodes from the cell while the cell is operating and reducing metal oxides in the cell chamber, (b) transporting the removed anodes and cathodes away from the cell, (c) transporting replacement anodes and cathodes to the cell, and (d) inserting the anodes and the cathodes into the cell while the cell is operating and reducing metal oxides in the cell chamber,
  • the anode/cathode handling apparatus includes (a) suitable vehicles 21 (one of which only is shown in Figure 1) adapted to move along the lines of the cells 3 and to transport anodes and cathodes to and from the cells, and (b) an overhead gantry (generally identified by the numeral 23) for facilitating removal of anodes and cathodes from the cell chamber 41 and insertion of anodes and cathodes into the cell chamber 41.
  • the anode/cathode handling apparatus includes a removal/insertion assembly that can be positioned above anodes and cathodes to be removed from the cell chamber 41 or above the positions for inserting replacement anodes and cathodes into the cell chamber 41 and can be operated to remove or insert anodes or cathodes, as required.
  • the electrochemical plant also includes an apparatus for removing metal from the cathodes that have been removed from the cell .
  • the electrochemical cell 3 includes a rectilinear cell chamber (typically 15 m long, 2 m wide, and 2 m high) defined by a base 5 and parallel side walls 7 and parallel end walls 9 extending outwardly from the base 5 formed from a suitable refractory material .
  • a rectilinear cell chamber typically 15 m long, 2 m wide, and 2 m high
  • the anodes and the cathodes in the electrochemical cell 3 are in the form of anode plates 33 and cathode plates 35 that are assembled together into anode/cathode modules (generally identified by the numeral 31) .
  • the anode/cathode modules 31 are positioned in side by side relationship in the cell chamber 41.
  • each anode/cathode module 31 includes a plurality of the anode plates 33 and a plurality of the cathode plates 35 in side by side relationship separated by a selected spacing, typically 40-60 mm. Preferably the spacing is 50 mm.
  • Each anode plate 33 includes a main anode member
  • Each cathode plate 35 includes a main cathode member 59.
  • the main cathode member 59 includes an assembly of an electrically conductive plate (which may be a solid plate or a mesh sheet) and metal oxide on both surfaces of the plate .
  • Each anode plate 33 and each cathode plate 35 includes a busbar hanger 39 that extends along the length of each plate.
  • the outer ends of the busbar hangers 39 are shaped to contact the inner ends of the fingers 13 of the busbar assembly.
  • the ends of the fingers 13 and the ends of the busbar hangers 39 are angled in a complimentary way, whereby there is effective electrical contact between these elements when the anode plates 33 and the cathode plates 35 are in operative positions in the cell chamber 41.
  • the inner ends of the fingers 13 are inclined to have upwardly facing contact surfaces, as viewed in Figure 1
  • the ends of the busbar hangers 39 are inclined to have complementary downwardly facing contact surfaces , as viewed in Figure 1.
  • Each cathode plate 35 includes an upper member 69.
  • Each cathode plate 35 includes tie rods 73 that connect the upper member 69 and the busbar hanger 39 together .
  • Each anode/cathode module 31 includes a support plate 51 that supports the anode plates 33 so that the anode plates 33 extend downwardly in a parallel , spaced- apart arrangement.
  • the support plate 51 defines a part of an airtight lid of the cell chamber 41.
  • the support plate 51 includes a plurality of parallel spaced-apart slots 53 that define openings through which the cathode plates 35 can be removed from and inserted into cell chamber 41.
  • the openings 53 and the cathode plates 35 are shaped and sized so that the cathode plates 35 form airtight seals when the cathode plates 35 are in an operative position in the anode/cathode module 31.
  • the operative position is shown in Figures 2, 3, and 8-10, with the cathode plates 35 positioned in the gaps between adjacent, parallel anode plates 33.
  • the cell contains a bath of the electrolyte at a selected temperature, typically at
  • a selected electrical potential of 3 V (or selected current) is applied to the anodes and the cathodes of the cell, and the titania of the cathode plates 35 progressively reduce in the cell.
  • the electrolyte is maintained at the required temperature by self-heating caused by resistance heating in the cell.
  • a key consideration in the change-over process is to achieve removal of a current cathode plate 35 and insertion of a replacement cathode plate 35 without allowing air to enter the cell chamber 41.
  • Minimising entry of air into the cell chamber 41 during normal operation of the cell i.e. at times other than during a cathode (and anode) changeover, is also a key consideration.
  • Water (which may be present as moisture in air) contacting the electrolyte is undesirable.
  • air both oxygen and nitrogen components
  • the purge apparatus (not shown) is provided to purge air from the cell chamber during the changeover process and during normal operation of the cell.
  • the cathode plates 35 may be individually removed at different locations along the entire length of the cell 3. Alternatively, the four cathode plates 35 in a given anode/cathode module 31 may be removed at a given changeover time.
  • Any suitable sequence of removal and replacement may be followed.
  • One consideration in this regard is to limit the numbers of cathode plates 35 to be removed (and replaced) at any given time to ensure that there are no significant variations in operating conditions in the cell. Typically, no more than 20% of the cathode plates 35 are removed at any given time.
  • the anodes are removed and replaced from time to time.
  • the anodes are consumed in the process and, consequently, must be replaced.
  • the anodes require replacement once every 10 times that a cathode plate 35 is replaced.
  • the embodiment of the electrochemical cell 3 shown in Figures 11-16 is similar to the electrochemical cell 3 shown in Figures 1-10 in terms of the basic cell construction.
  • the cell 3 includes (a) a cell chamber 41 defined by a base (not shown) , side walls 7 and parallel end walls 9, (b) a lid (generally identified by the numeral 61) positioned on the cell chamber 41 and forming an air-tight seal with the cell chamber 41, and (c) a plurality of anode/cathode modules 31 (only one of which is shown in Figure 11 for clarity) extending through openings in the lid 61 into the cell chamber 41 and at least partially immersed in a molten bath of electrolyte 71 located in the cell chamber 41.
  • anode/cathode module 31 Whilst only one anode/cathode module 31 is shown in Figure 11, it can readily be appreciated that under normal operating conditions the cell 3 includes a plurality of such anode/cathode modules 31 positioned in side-side relationship along the length of the cell chamber 41.
  • Each anode/cathode module 31 includes (a) an upper horizontal support plate 51a and a lower horizontal parallel support plate 51b that are connected together by vertical posts 91 and (b) two anode assemblies and a cathode assembly supported by the support plates 51a, 51b.
  • Each anode assembly includes a line of nine vertical, graphite anode rods 73.
  • Each anode assembly also includes an anode support assembly. Specifically, groups of three of the anode rods 73 in each line are supported by (a) a horizontal cross member 75 connected to upper ends of the anode rods 73 and (b) a support rod 77 that extends vertically upwardly from the cross member 75 and the anode rods 73.
  • the cathode assembly includes (a) a support frame
  • the support frame 87 of the cathode assembly includes a main support body that includes (a) a horizontal cross member 81, (b) a plurality of parallel, vertical support rods 83 extending from the cross member, (c) a plurality of pins 85 extending outwardly from opposite sides of the support rods 83 and defining mounting posts for the cathode elements 95, and (d) three support rods 89 that extend vertically upwardly from the cross member 81.
  • the support rods 77 of the anode assemblies and the support rods 89 of the cathode assembly extend vertically through openings in the support plates 5a, 5b and are supported by the support plates and are electrically isolated from the support plates .
  • the support rods 77 are electrically connected to a power source (not shown) to supply electricity to the anode assemblies and the cathode assembly to apply a potential between the assemblies that is above the decomposition potential of CaO and thereby facilitate electrochemical reduction of the metal oxide of the honeycomb-shaped cathode elements 95.
  • honeycomb-shaped cathode elements 95 are formed from the metal oxide to be reduced in the cell 3.
  • each cathode element 95 includes a series of interconnected walls 103 that define ⁇ '- plurality of passages 97 for the electrolyte to penetrate the structure to contact internal exposed surfaces of the structure. More specifically, each cathode element 95 shown in the Figures has a relatively thin walled structure that defines sixteen parallel passages 97. The arrangement is such that the electrolyte can readily penetrate the structure and contact exposed interior surfaces via the passages 97. In overall terms , the structure is such that there is a substantial surface area of the metal oxide that is exposed to the electrolyte .
  • the cathode elements 95 are formed to have sufficient mechanical strength to withstand handling after manufacture and during assembly of the cathode and during and after reduction in the cell 3.
  • the post-reduction handling includes washing the cathode elements 95 after the elements have been removed from a cell 3 to remove retained electrolyte from the elements and grit blasting the washed elements to remove any solidified accretions not removed in the washing step.
  • the cathode elements 95 have to be sufficiently tough to withstand physical size changes that occur as a consequence of phase changes during reduction.
  • the cathode elements 95 are formed by extruding a slurry of powders of the metal oxide and water into a continuous length of the honeycomb shape shown in the Figures, cutting the continuous length into the required length, and then sintering the elements to increase the strength of the elements .

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Abstract

L'invention concerne une pile électrochimique produite à l'échelle commerciale, pour la mise en oeuvre d'un processus électrochimique de réduction d'un oxyde métallique tel qu'un oxyde de titane à un état solide. La pile comprend plusieurs cathodes qui sont formées au moins en partie à partir de l'oxyde métallique et peuvent être retirées de la pile et remplacées par d'autres cathodes similaires pendant que le processus se poursuit dans la pile, continuant ainsi à réduire l'oxyde métallique dans la pile.
PCT/AU2008/000220 2007-02-20 2008-02-20 Réduction électrochimique d'oxydes métalliques WO2008101283A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2007900858A AU2007900858A0 (en) 2007-02-20 Cell arrangement
AU2007900858 2007-02-20

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WO2008101283A1 true WO2008101283A1 (fr) 2008-08-28

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010131000A1 (fr) * 2009-05-12 2010-11-18 Metalysis Limited Appareil et procédé permettant une diminution d'une charge d'alimentation solide
WO2012066299A1 (fr) * 2010-11-18 2012-05-24 Metalysis Limited Procédé et système de réduction électrolytique d'une charge d'alimentation solide
WO2016209575A1 (fr) * 2015-06-25 2016-12-29 Ge-Hitachi Nuclear Energy Americas Llc Structure de combustible nucléaire et procédé de fabrication d'une structure de combustible nucléaire à l'aide d'un matériau de cathode détachable
US9725815B2 (en) 2010-11-18 2017-08-08 Metalysis Limited Electrolysis apparatus

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EA025506B1 (ru) * 2009-05-12 2016-12-30 Металисиз Лимитед Установка и способ для восстановления твердого исходного сырья
KR101770839B1 (ko) 2009-05-12 2017-08-23 메탈리시스 리미티드 고체 공급재료를 환원시키기 위한 장치 및 방법
WO2010131000A1 (fr) * 2009-05-12 2010-11-18 Metalysis Limited Appareil et procédé permettant une diminution d'une charge d'alimentation solide
JP2012526918A (ja) * 2009-05-12 2012-11-01 メタリシス リミテッド 固体原料の還元のための装置および方法
CN102459711A (zh) * 2009-05-12 2012-05-16 金属电解有限公司 用来还原固体原料的设备和方法
US8747644B2 (en) 2009-05-12 2014-06-10 Metalysis Limited Apparatus and method for reduction of a solid feedstock
US8992758B2 (en) 2009-05-12 2015-03-31 Metalysis Limited Apparatus and method for reduction of a solid feedstock
KR101770838B1 (ko) 2009-05-12 2017-08-23 메탈리시스 리미티드 고체 공급재료의 환원 장치 및 방법
AP3805A (en) * 2009-05-12 2016-08-31 Metalysis Ltd Apparatus and method for reduction of a solid feedstock
KR101770873B1 (ko) * 2010-11-18 2017-08-23 메탈리시스 리미티드 전기분해 장치
WO2012066299A1 (fr) * 2010-11-18 2012-05-24 Metalysis Limited Procédé et système de réduction électrolytique d'une charge d'alimentation solide
AP4025A (en) * 2010-11-18 2017-02-04 Metalysis Ltd Method and system for electrolytically reducing a solid feedstock
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AU2011330972B2 (en) * 2010-11-18 2016-07-21 Metalysis Limited Method and system for electrolytically reducing a solid feedstock
KR101824288B1 (ko) * 2010-11-18 2018-01-31 메탈리시스 리미티드 고체 공급원료를 전해 환원시키는 방법 및 시스템
DK179172B1 (en) * 2010-11-18 2018-01-02 Metalysis Ltd Method and system for electrolytically reducing a solid feedstock
CN103237926A (zh) * 2010-11-18 2013-08-07 金属电解有限公司 用于电解还原固体进料的方法和系统
EA029746B1 (ru) * 2010-11-18 2018-05-31 Металисиз Лимитед Способ и система электролитического восстановления твердого сырья
AU2011330972C1 (en) * 2010-11-18 2017-01-19 Metalysis Limited Method and system for electrolytically reducing a solid feedstock
EP4075448A1 (fr) * 2015-06-25 2022-10-19 Ge-Hitachi Nuclear Energy Americas LLC Procédé de fabrication d'une plaque cathodique et assemblage d'une plaque cathodique
WO2016209575A1 (fr) * 2015-06-25 2016-12-29 Ge-Hitachi Nuclear Energy Americas Llc Structure de combustible nucléaire et procédé de fabrication d'une structure de combustible nucléaire à l'aide d'un matériau de cathode détachable
US10221499B2 (en) 2015-06-25 2019-03-05 Ge-Hitachi Nuclear Energy Americas Llc Nuclear fuel structure and method of making a nuclear fuel structure using a detachable cathode material

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