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EP0198775B1 - Verfahren zur kontinuierlichen Überwachung des Gehalts eines in einem geschmolzenen Salzbad aufgelösten Metalls und dessen Anwendung zur kontinuierlichen Zufuhr dieser Metallsalze in einer Elektrolysezelle - Google Patents

Verfahren zur kontinuierlichen Überwachung des Gehalts eines in einem geschmolzenen Salzbad aufgelösten Metalls und dessen Anwendung zur kontinuierlichen Zufuhr dieser Metallsalze in einer Elektrolysezelle Download PDF

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Publication number
EP0198775B1
EP0198775B1 EP86420087A EP86420087A EP0198775B1 EP 0198775 B1 EP0198775 B1 EP 0198775B1 EP 86420087 A EP86420087 A EP 86420087A EP 86420087 A EP86420087 A EP 86420087A EP 0198775 B1 EP0198775 B1 EP 0198775B1
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EP
European Patent Office
Prior art keywords
bath
metal
cell
dissolved
potential
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
EP86420087A
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English (en)
French (fr)
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EP0198775A1 (de
Inventor
Jean-Pierre Garnier
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.)
Generale Des Matieres Nucleaires compagn Cie
Original Assignee
Pechiney SA
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Filing date
Publication date
Application filed by Pechiney SA filed Critical Pechiney SA
Priority to AT86420087T priority Critical patent/ATE34586T1/de
Publication of EP0198775A1 publication Critical patent/EP0198775A1/de
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Publication of EP0198775B1 publication Critical patent/EP0198775B1/de
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    • 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 present invention which results from work carried out in the laboratories of the lich Nationale Su Southerneure d'Electrochimie et d'Electrométallurgie de Grenoble, relates to a process for continuous control of the content of transition metal dissolved in a bath of molten salts and its application to the continuous supply of an electrolysis cell with salts of said metal.
  • transition metals can be obtained industrially by continuous electrolysis in a cell of at least one of their chlorides previously dissolved in a bath of molten salts constituted by alkali chlorides and / or alkaline earth. He also knows from FR-A-1154129 that a mixture of alkali metal chloride and alkali metal fluoride can be used as molten salts.
  • transition metal is understood here to mean any metal belonging to columns IVa, Va, Via of the specific classification of Mendeleev and in particular titanium, zirconium, hafnium, tantalum, niobium and vanadium.
  • Continuous electrolysis is also understood to mean a process in which the deposition and extraction of the metal at the cathode and the release of chlorine at the anode are constantly compensated by an addition of fresh chloride; this contribution being intended to maintain the content of metal to be produced dissolved in the bath at a relatively constant value and preferably optimal, that is to say the most favorable for a good functioning of the cell.
  • the cell In such a process, if it is actually wanted to keep the dissolved metal content at a constant value, the cell must be supplied with a quantity of fresh chlorides corresponding exactly to the quantity consumed by the cell.
  • the generally adopted solution consists in periodically taking bath samples, analyzing them and adjusting accordingly the amounts of chloride in the metal to be fed. But this operation is not simple and above all its response is not immediate, so that if the drifts are more or less reduced periodically, the chloride content of the metal dissolved in the bath is rarely equal to the optimal content.
  • the method therefore consists, knowing the optimal metal content to ensure proper functioning of the cell, to calculate from this content and the molar ratio claimed the amount of fluorides to be added.
  • This fluoride is introduced into the bath at the time of its constitution.
  • the cell being equipped with an indicator electrode and a reference electrode, the optimal amount of chloride of the transition metal to be deposited is charged and after a time sufficient to allow the dissolution, the potential is measured before starting the electrolysis properly said.
  • the dissolved metal content can be confirmed by analysis of the bath.
  • the cell is then put into service and regular operation can be achieved by supplying it with chlorides of the metal so that the measured potential remains constant. It is easy to see the application that can be made of this measurement to the continuous supply of the cell. It suffices to compare the potential measured at all times at the setpoint potential corresponding to the optimal content of the bath and to control the supply of chlorides accordingly. In this way, one can very finely regulate the flow of chlorides of the metal and have an extremely precise dissolved metal content throughout the electrolysis.
  • the internal wall of the cell is metallic, it has been found that it could be used as an indicator electrode. Indeed, knowing that this must be constituted by the metal to be deposited, we tried during a preelectrolysis in the presence of the chloride of the metal to be deposited, to pass a direct current between the anode of the cell and the wall of the tank. Under these conditions, it has been found that the deposit of metal obtained on the tank can play perfectly thereafter the role of indicator electrode. If necessary, this deposit on the wall can be periodically reconstituted during electrolysis or even created permanently by cathodic polarization of the cell.
  • the applicant has also sought to eliminate the installation of a reference electrode; it achieved this by replacing it with the cell anode.
  • a reference electrode it achieved this by replacing it with the cell anode.
  • an ohmic drop is established in the potential control circuit due to the electrolysis current I which passes through the anode. This disturbs the measurement and gives an incorrect indication of the actual content of dissolved chlorides in the bath.
  • the applicant incorporates between the indicator electrode and the anode an ohmic drop corrector, the constitution of which is described below.
  • a direct current source (13) whose positive pole is connected to the anode and the negative pole to the cathode of the cell respectively by the conductors (14) and (15);
  • the terminals A and D of the device (16) are connected to a comparator (19) of the measured potential to the reference potential which sends a signal via the conductor (20) to the motor (11) in the event that the measured potential is in absolute value greater than the absolute value of the reference potential.
  • the ohmic drop corrector comprising an operational amplifier denoted AOP, two resistors of the same value R1, a variable and adjustable resistance Rv.
  • a calibration is carried out which consists in adjusting the value of Rv so as to obtain:
  • This signal S is sent to the comparator (19).
  • the invention finds its application in all cases where it is desired to manufacture transition metals by continuous electrolysis of their chlorides in the molten baths of alkali or alkaline earth chlorides.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)

Claims (5)

1. Verfahren zur kontinuierlichen Überwachung des Gehalts eines in einem Chloridschmelzbad gelösten Übergangsmetalls in einer Elektrolysezelle zur Herstellung des Metalls aus mindestens einem seiner Chloride, wobei die Spannung einer in das Bad eintauchenden Meßelektrode aus dem Übergangsmetall im Vergleich zu einer Bezugselektrode bestimmt wird, dadurch gekennzeichnet, daß in das Bad eine solche Menge an Alkali- und/oder Erdalkalifluoriden eingebracht wird, daß das Molverhältnis von Fluor zu gelöstem Übergangsmetall von 2,5 bis 15 beträgt.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß ein Molverhältnis von 4 bis 8 verwendet wird.
3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß eine Meßelektrode verwendet wird, die aus der Metallwand der Zelle, auf die das Übergangsmetall niedergeschlagen wurde, besteht.
4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Bezugselektrode aus der Anode der Elektrolysezelle, die mit einem Regler für den Ohmschen Spannungsabfall ausgerüstet ist, besteht.
5. Anwendung des Verfahrens nach Anspruch 1 zur kontinuierlichen Versorgung der Zelle mit Übergangsmetallchlorid, dadurch gekennzeichnet, daß die gemessene Spannung mit einer Einstellspannung verglichen wird, die dem optimalen Gehalt des Bads an Übergangsmetallchlorid entspricht und die Zufuhr regelt, solange der Absolutwert der gemessenen Spannung über dem Absolutwert der Einstellspannung bleibt.
EP86420087A 1985-03-28 1986-03-26 Verfahren zur kontinuierlichen Überwachung des Gehalts eines in einem geschmolzenen Salzbad aufgelösten Metalls und dessen Anwendung zur kontinuierlichen Zufuhr dieser Metallsalze in einer Elektrolysezelle Expired EP0198775B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86420087T ATE34586T1 (de) 1985-03-28 1986-03-26 Verfahren zur kontinuierlichen ueberwachung des gehalts eines in einem geschmolzenen salzbad aufgeloesten metalls und dessen anwendung zur kontinuierlichen zufuhr dieser metallsalze in einer elektrolysezelle.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8505196 1985-03-28
FR8505196A FR2579629B1 (fr) 1985-03-28 1985-03-28 Procede de controle en continu de la teneur en metal dissous dans un bain de sels fondus et son application a l'alimentation continue d'une cellule d'electrolyse en sels dudit metal

Publications (2)

Publication Number Publication Date
EP0198775A1 EP0198775A1 (de) 1986-10-22
EP0198775B1 true EP0198775B1 (de) 1988-05-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP86420087A Expired EP0198775B1 (de) 1985-03-28 1986-03-26 Verfahren zur kontinuierlichen Überwachung des Gehalts eines in einem geschmolzenen Salzbad aufgelösten Metalls und dessen Anwendung zur kontinuierlichen Zufuhr dieser Metallsalze in einer Elektrolysezelle

Country Status (7)

Country Link
US (1) US4657643A (de)
EP (1) EP0198775B1 (de)
JP (1) JPS61227191A (de)
AT (1) ATE34586T1 (de)
CA (1) CA1251161A (de)
DE (1) DE3660222D1 (de)
FR (1) FR2579629B1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2691169B1 (fr) * 1992-05-12 1994-07-01 Cezus Co Europ Zirconium Alliages de metaux refractaires aptes a la transformation en lingots homogenes et purs et procedes d'obtention des dits alliages.
JP2015098626A (ja) * 2013-11-19 2015-05-28 住友電気工業株式会社 精製金属の製造方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2828251A (en) * 1953-09-30 1958-03-25 Horizons Titanium Corp Electrolytic cladding process
FR1154129A (fr) * 1955-05-31 1958-04-02 Union Carbide & Carbon Corp Procédé électrolytique semi-continu
US2975111A (en) * 1958-03-19 1961-03-14 New Jersey Zinc Co Production of titanium
FR2494725A1 (fr) * 1980-11-27 1982-05-28 Armand Marcel Nouveau dispositif et procede pour l'alimentation en ticl4 des cellules d'electrolyse pour la preparation du titane

Also Published As

Publication number Publication date
US4657643A (en) 1987-04-14
CA1251161A (fr) 1989-03-14
ATE34586T1 (de) 1988-06-15
FR2579629B1 (fr) 1987-05-07
EP0198775A1 (de) 1986-10-22
FR2579629A1 (fr) 1986-10-03
JPS61227191A (ja) 1986-10-09
DE3660222D1 (en) 1988-06-30
JPH033753B2 (de) 1991-01-21

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