EP0053564B1 - Verfahren zum Überwachen der Diaphragmadurchlässigkeit während der elektrolytischen Vorbereitung mehrwertiger Metalle und Elektrolysezelle zur Durchführung dieses Verfahrens - Google Patents

Verfahren zum Überwachen der Diaphragmadurchlässigkeit während der elektrolytischen Vorbereitung mehrwertiger Metalle und Elektrolysezelle zur Durchführung dieses Verfahrens Download PDF

Info

Publication number
EP0053564B1
EP0053564B1 EP81420172A EP81420172A EP0053564B1 EP 0053564 B1 EP0053564 B1 EP 0053564B1 EP 81420172 A EP81420172 A EP 81420172A EP 81420172 A EP81420172 A EP 81420172A EP 0053564 B1 EP0053564 B1 EP 0053564B1
Authority
EP
European Patent Office
Prior art keywords
diaphragm
electrolysis
electrolyte
titanium
permeability
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.)
Expired
Application number
EP81420172A
Other languages
English (en)
French (fr)
Other versions
EP0053564A1 (de
Inventor
Marcel Armand
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.)
Pechiney SA
Original Assignee
Pechiney SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pechiney SA filed Critical Pechiney SA
Priority to AT81420172T priority Critical patent/ATE20481T1/de
Publication of EP0053564A1 publication Critical patent/EP0053564A1/de
Application granted granted Critical
Publication of EP0053564B1 publication Critical patent/EP0053564B1/de
Expired legal-status Critical Current

Links

Images

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
    • 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

Definitions

  • the process which is the subject of the invention relates to the preparation of polyvalent metals such as titanium, zirconium, hafnium, vanadium, niobium or tantalum by electrolysis in molten salt baths of their halides dissolved in one or more alkali or alkaline earth halides.
  • This process applies more particularly to the preparation of titanium by electrolysis of a bath of molten halides.
  • This diaphragm must, on the other hand, allow the alkaline or alkaline-earth ions to pass, as well as the halogen ions which transport most of the current.
  • this diaphragm In general, the permeability of this diaphragm must be sufficient to allow the circulation of the electrolyte in order to balance the pressures in the two compartments, while making as much as possible an obstacle to the passage of the metal to be deposited, in ionic form. or not towards the anode compartment.
  • This structure is preferably made up of a grid or a perforated screen made of nickel or a nickel-based alloy. In order to give it a sufficiently low permeability for it to act as a diaphragm, it is covered with an electrolytic deposit of titanium in the electrolysis cell itself. For this, this structure is connected to the electrical supply circuit of the cell, so as to make it play the role of a cathode. The titanium deposit which then forms partially plugs the holes.
  • the FR patent. 2423 555 describes another embodiment of a diaphragm for cells used for the electrolytic preparation of polyvalent metals. These diaphragms are preferably formed by a metallic nickel cloth on which an electrolytic or non-electrolytic deposition of cobalt has been carried out.
  • connection between anolyte and catholyte is gradually cut and the diaphragm starts to function like a bipolar electrode. This most often results in destruction of the diaphragm, either by corrosion or by crushing.
  • a process has therefore been sought which makes it possible to avoid such drawbacks and, in particular, to considerably extend the life of the diaphragms used for the preparation of polyvalent metals by electrolysis.
  • Such a method must also make it possible to maintain a high current yield, both with regard to the deposition of the polyvalent metal at the cathode and with regard to the release of halogen at the anode. Finally, it must make it possible to maintain the voltage at the terminals of the electrolysis cell within the determined limits corresponding to operating conditions close to the optimum.
  • the process which is the subject of the invention consists in controlling the permeability of the diaphragm of an electrolysis cell for the preparation of polyvalent metals such as Ti, Zr, Hf, V, Nb and Ta from a electrolyte based on molten metal halides, thanks to the formation of a deposit of the metal to be obtained on this diaphragm, said diaphragm being able to be positively or negatively polarized;
  • this process is characterized in that the drop in potential in the electrolyte bath permeating the diaphragm is measured continuously and without interrupting the operation of the electrolysis, and in that a direct electric current is sent into the said diaphragm whose intensity and direction are slaved to the said drop in potential so as to maintain the permeability within determined limits.
  • This partial growth or redissolution of a deposit of a polyvalent metal is carried out without interrupting the operation of the electrolysis, continuously or discontinuously at constant or variable speed.
  • FIG. 1 is the diagram of a diaphragm electrolysis cell, particularly suitable for the preparation by electrolysis of titanium, the general arrangement of which is similar to that described in the USBM report No. 764S-1972 entitled “Use of composite diaphragm in the Electrowinning of titanium (fig. 1, p. 3).
  • This cell comprises a receptacle (1) made of refractory steel heated from the outside by known and not described means which make it possible to bring the electrolyte (2) to a temperature of approximately 550 ° C.
  • This consists of a LiCIKCI eutectic mixture containing titanium in solution, in the form of chlorides at a concentration of approximately 1 to 3% by weight of Ti.
  • a graphite anode (3) is immersed in the electrolyte and is surrounded by a diaphragm (4). This anode is connected by a rod (5) to the positive pole of a current source, not shown.
  • a supply cathode consists of a mild steel tube (6) connected to the negative pole of a current source, not shown. This cathode is supplied with TiCI 4 by the connection tube (7) from an injection system not shown. The end of the tube (6) has a perforated zone (8) also made of mild steel immersed in the electrolyte.
  • a mild steel deposition cathode (9) is also connected to the negative pole of the current source.
  • a current distributor device, not shown, makes it possible to fix the ratio between the currents I 1 and 1 2 which pass respectively through the supply (6) and deposition (9) cathodes.
  • the current flowing through the anode has an intensity 1 equal to I 1 + I 2 .
  • an Ni grid is used which has been coated with a Ti deposit by a suitable method, such as that described in the US patent. No. 2,789,943, so as to reduce the permeability to the desired level.
  • the amount of TiCl 4 injected through the supply cathode is such that the concentration of Ti dissolved in the electrolyte is preferably maintained in the concentration range of 1 to 3% by weight of Ti.
  • the diaphragm in Figure 2 shows the distribution of potentials in the electrolysis cell during its operation.
  • the potential (P) which exists in the electrolysis cell in operation in the interval between cathode and anode is represented on the ordinate, represented on the abscissa.
  • Cathode C, diaphragm D and anode A are shown schematically.
  • the straight sections a, b and c respectively represent the potential variations which occur in the catholyte, in the electrolyte which impregnates the diaphragm and in the anolyte.
  • the vertical vectors P i , P 2 . P 3 and P 4 respectively represent the potential differences between the cathode, the cathode and anode faces of the diaphragm and the anode with respect to the electrolyte in contact.
  • the variation of the potential “b” is equal to the product of 1 (electrolysis current) by R D (resistance of the electrolyte which permeates the diaphragm).
  • 1 x R D varies in the opposite direction to the permeability.
  • the equilibrium potential of the diaphragm P 3 with respect to the anolyte is defined by the formula:
  • the conventions are the same as in the previous one and “a Ti2- anodic represents the activity of Ti2 + ions in the anolyte.
  • IR D is therefore a measure of the efficiency of the diaphragm as a means of preventing the diffusion of titanium ions towards the anolyte.
  • the diaphragm becomes bipolar and an alkali or alkaline earth deposit appears on the face of the diaphragm opposite the anode.
  • the current yield on the anode side then collapses quickly by recombination of the chlorine released at the anode with the alkalis formed.
  • chlorine ions are discharged which cause a rapid attack on this diaphragm.
  • too high permeability of the diaphragm is undesirable since the diffusion of Ti ions from the catholyte to the anolyte in too large a quantity would lead to too great a reduction in yield.
  • the method for controlling the permeability of the diaphragm according to the invention consists in controlling the deposition of titanium which takes place there more or less naturally either with a view to increasing it, or with a view to partially redissolving it, this growth or this redissolution being subject to the variation of the voltage drop across the electrolyte which permeates the diaphragm. It is thus possible, in an extremely simple manner, to choose in advance, according to the characteristics of the cell, a special value of this drop in potential and to keep it within a determined range.
  • the potential drop across the diaphragm should be kept below a upper limit, of the order of a volt, which corresponds to the difference between the deposition potential of Ti2 + and that of the alkali or alkaline earth metal.
  • a upper limit of the order of a volt, which corresponds to the difference between the deposition potential of Ti2 + and that of the alkali or alkaline earth metal.
  • this difference should not exceed the value which corresponds to the discharge of alkaline ions on the diaphragm.
  • a particularly advantageous device represented in FIG. 3 consists in connecting the diaphragm to a current source capable of ensuring the passage of this current in both directions, the other pole of this source being connected to the cathode.
  • FIG. 3 schematically represents an electrolysis cell whose design derives from that of the cell in FIG. 1.
  • the metal electrolysis cell (10) contains the electrolyte (11) whose composition is similar to that described above for the preparation of titanium.
  • the anode (12) is surrounded by a diaphragm (15).
  • the anode is connected, as usual, to the positive pole of a first current source not shown, whose negative pole is connected to the cathodes.
  • the diaphragm is connected either to the positive pole or to the negative pole of a second source of current not shown, the other pole of which is connected to the cathode, and which is capable of ensuring the passage through this diaphragm of a current 1 3 in the desired direction.
  • the TiCI 4 supply cathode (14) and the deposition cathode (15) are similar to those already described in FIG. 1.
  • a device known to a person skilled in the art enables the direction and intensity 1 3 of the current injected into the diaphragm to be controlled by the variation in the voltage drop IR D , through the electrolyte permeating that this, which is detected by one of the means described above and, for example, by the continuous measurement of the potential difference between the diaphragm and the anode.
  • the injection of current 1 3 through the diaphragm is started as soon as the voltage drop across the electrolyte permeating it deviates in one direction or the other from the reference voltage.
  • the servo-control makes it possible to inject a current 1 3 in the desired direction the more intense the greater the difference between the voltage drop across the electrolyte impregnating the diaphragm and the reference voltage.
  • the process is self-regulating, that is to say so that the increase in the intensity of the current as a function of the voltage difference is greater than the value strictly necessary, in order to accelerate the deposit or dissolution and thus promote, as far as possible, a return to normal conditions of permeability of the diaphragm.
  • the means for controlling the permeability of the diaphragm according to the invention which has just been described, can be applied not only to the case of titanium, but also to that of the preparation by electrolysis of other polyvalent metals such as zirconium. , hafnium, vanadium, niobium or tantalum.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
  • Professional, Industrial, Or Sporting Protective Garments (AREA)
  • Secondary Cells (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)

Claims (3)

1. Verfahren zum Steuern der Durchlässigkeit des Diaphragmas einer Elektrolysezelle zur Gewinnung vielwertiger Metalle, wie z. B. Ti, Zr, Hf, V, Nb oder Ta, aus einem Elektrolyt auf Basis geschmolzener Metallhalogenide, in dem dieses Diaphragma mit einer Abscheidung des abzuscheidenden Metalls bedeckt wird und positiv oder negativ polarisiert werden kann, dadurch gekennzeichnet, daß man kontinuierlich und ohne Unterbrechen des Elektrolysebetriebs den Potentialabfall in dem das Diaphragma imprägnierenden Elektrolytbad mißt und in dieses Diaphragma einen elektrischen Gleichstrom leitet, dessen Stärke und Richtung aufgrund dieses Potentialabfalls derart gesteuert werden, um die Permeabilität im Inneren bestimmter Grenzen beizubehalten.
2. Verfahren nach dem Anspruch 1, dadurch gekennzeichnet, daß man den Potentialabfall zwischen zwei in den Elektrolyt zu beiden Seiten des Diaphragmas eintauchenden Elektroden mißt.
3. Verfahren nach dem Anspruch 1, dadurch gekennzeichnet, daß man den Potentialabfall zwischen der Anode der Zelle und dem Diaphragma mißt.
EP81420172A 1980-11-27 1981-11-25 Verfahren zum Überwachen der Diaphragmadurchlässigkeit während der elektrolytischen Vorbereitung mehrwertiger Metalle und Elektrolysezelle zur Durchführung dieses Verfahrens Expired EP0053564B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81420172T ATE20481T1 (de) 1980-11-27 1981-11-25 Verfahren zum ueberwachen der diaphragmadurchlaessigkeit waehrend der elektrolytischen vorbereitung mehrwertiger metalle und elektrolysezelle zur durchfuehrung dieses verfahrens.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8025504A FR2494728A1 (fr) 1980-11-27 1980-11-27 Procede de controle de la permeabilite des diaphragmes dans la preparation de metaux polyvalents par electrolyse et cellule d'electrolyse pour la mise en oeuvre de ce procede
FR8025504 1980-11-27

Publications (2)

Publication Number Publication Date
EP0053564A1 EP0053564A1 (de) 1982-06-09
EP0053564B1 true EP0053564B1 (de) 1986-06-18

Family

ID=9248544

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81420172A Expired EP0053564B1 (de) 1980-11-27 1981-11-25 Verfahren zum Überwachen der Diaphragmadurchlässigkeit während der elektrolytischen Vorbereitung mehrwertiger Metalle und Elektrolysezelle zur Durchführung dieses Verfahrens

Country Status (7)

Country Link
US (1) US4392924A (de)
EP (1) EP0053564B1 (de)
JP (1) JPS5834552B2 (de)
AT (1) ATE20481T1 (de)
DE (1) DE3174851D1 (de)
FR (1) FR2494728A1 (de)
NO (1) NO155703C (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2560896B1 (fr) * 1984-03-12 1989-10-20 Pechiney Procede d'obtention d'un metal par electrolyse d'halogenures en bain de sels fondus comportant un double depot simultane et continu et dispositifs d'application
US4686025A (en) * 1984-03-12 1987-08-11 Pechiney Apparatus for the production of a metal by electrolyzing halides in a molten salt bath, by a simultaneous continuous double deposit
ES8609513A1 (es) * 1985-06-21 1986-09-01 Hermana Tezanos Enrique Nuevo diseno de catodo para beneficio electroquimico de me- tales
WO1991002360A1 (en) * 1989-06-30 1991-02-21 Schoessow Glen J Electrochemical nuclear process and apparatus for producing tritium, heat, and radiation
JP5504515B2 (ja) * 2008-05-01 2014-05-28 独立行政法人産業技術総合研究所 希土類金属の回収方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2789943A (en) * 1955-05-05 1957-04-23 New Jersey Zinc Co Production of titanium

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1149544A (fr) * 1955-05-05 1957-12-27 New Jersey Zinc Co Production de titane
FR2405311A1 (fr) * 1977-10-10 1979-05-04 Sred Az I Tsvetnoi Procede de controle et d'optimalisation automatiques du regime de depot electrolytique d'un metal et dispositif pour sa mise en oeuvre
FR2423555A1 (fr) * 1978-04-21 1979-11-16 Dow Chemical Co Appareil et procede pour l'obtention par electrolyse de metaux polyvalents
JPS5914556B2 (ja) * 1978-04-28 1984-04-05 ザ ダウ ケミカル カンパニ− チタン電解製造用金属性隔膜および該隔膜を使用する電解槽と該電解槽中でのチタン製造法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2789943A (en) * 1955-05-05 1957-04-23 New Jersey Zinc Co Production of titanium

Also Published As

Publication number Publication date
FR2494728B1 (de) 1984-03-02
JPS5834552B2 (ja) 1983-07-27
NO155703C (no) 1987-05-13
EP0053564A1 (de) 1982-06-09
US4392924A (en) 1983-07-12
DE3174851D1 (en) 1986-07-24
ATE20481T1 (de) 1986-07-15
JPS57116789A (en) 1982-07-20
FR2494728A1 (fr) 1982-05-28
NO814028L (no) 1982-05-28
NO155703B (no) 1987-02-02

Similar Documents

Publication Publication Date Title
EP0037325B1 (de) Elektrolytisches Verfahren unter Verwendung poröser Elektroden und dessen Anwendung zur Metallgewinnung aus wässrigen Lösungen
EP0113931B1 (de) Kathode zur elektrolytischen Herstellung von Wasserstoff und ihre Anwendung
EP0556112B1 (de) Iontophoreseeinrichtung zur transdermalen Verabreichung einer vorgegebenen Gesamtmenge von aktiven Grundstoffen an ein Lebewesen
EP0053564B1 (de) Verfahren zum Überwachen der Diaphragmadurchlässigkeit während der elektrolytischen Vorbereitung mehrwertiger Metalle und Elektrolysezelle zur Durchführung dieses Verfahrens
CA2208913C (fr) Procede de regulation de la teneur en alumine du bain des cuves d'electrolyse pour la production d'aluminium
EP0038244B1 (de) Verfahren zur Ablagerung auf leitungsfähigen Oberflächen, insbesondere auf Metalloberflächen, dünner organischer Filme durch Elektropolymerisierung und so erhaltene dünne Filme
FR2643653A1 (fr) Diaphragme pour electrolyse en bain de sels fondus d'halogenures de metaux
EP0053565B1 (de) Vorrichtung und Verfahren zur Zufuhr von TiCl4 in Elektrolysezellen für die Titanherstellung
FR2723107A1 (fr) Procede de reduction electrolytique d'un disulfure et produit ainsi obtenu
FR2462489A1 (fr) Procede de preparation d'electrodes a faible surtension d'hydrogene, electrodes ainsi formees et application a l'electrolyse des solutions aqueuses de chlorures alcalins
US4416746A (en) Bipolar refining of lead
EP3555345B1 (de) Elektrolytisches verfahren zur extraktion von zinn oder gleichzeitig zinn und blei enthalten in einem elektrisch leitenden gemisch
EP0061392A1 (de) Verfahren und Vorrichtung zur Elektrobehandlung von gemischten pulverigen Stoffen
FR2680523A1 (fr) Procede d'electrodeposition.
EP1838903B1 (de) Verfahren zur galvanischen abscheidung eines metalls zur herstellung von zellen mit elektroden-polymerfestelektrolyt
EP0410919A1 (de) Verfahren zur Elektroplattierung einer Metalloberfläche und Elektrolysezelle zur Durchführung des Verfahrens
EP0197867B1 (de) Verfahren zur Erhöhung der Reinheit von Übergangsmetallen, die durch Elektrolyse aus ihren geschmolzenen Halogeniden gewonnen werden
EP0527882B1 (de) Vorrichtung und verfahren für die elektrolyse mit poröser elektrode
EP2173928A1 (de) Anlage und verfahren zur elektrolytischen verzinnung von stahlstreifen mithilfe einer nichtlöslichen anode
CA1323596C (fr) Procede d'anodisation passive du cuivre en milieu de fluorures fondus. application la protection de pieces en cuivre des electrolyseurs fluor
FR3128456A1 (fr) Procédé de production d’hydrogène sous pression par électrolyse de l’eau découplée
FR2544751A1 (fr) Elimination de l'argent de melanges de chlorure complexes d'argent et de cuivre
BE481455A (de)
BE521185A (de)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT DE GB IT SE

17P Request for examination filed

Effective date: 19820622

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: PECHINEY

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT DE GB IT SE

REF Corresponds to:

Ref document number: 20481

Country of ref document: AT

Date of ref document: 19860715

Kind code of ref document: T

ITF It: translation for a ep patent filed
REF Corresponds to:

Ref document number: 3174851

Country of ref document: DE

Date of ref document: 19860724

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19911023

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19921126

ITTA It: last paid annual fee
EUG Se: european patent has lapsed

Ref document number: 81420172.9

Effective date: 19930610

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19961014

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19961019

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19961023

Year of fee payment: 16

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19971125

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19971125

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19971125

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980801