EP0197867B1 - Procédé d'amélioration de la pureté des métaux de transition obtenus par électrolyse de leurs halogénures en bain de sels fondus - Google Patents

Procédé d'amélioration de la pureté des métaux de transition obtenus par électrolyse de leurs halogénures en bain de sels fondus Download PDF

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Publication number
EP0197867B1
EP0197867B1 EP86420077A EP86420077A EP0197867B1 EP 0197867 B1 EP0197867 B1 EP 0197867B1 EP 86420077 A EP86420077 A EP 86420077A EP 86420077 A EP86420077 A EP 86420077A EP 0197867 B1 EP0197867 B1 EP 0197867B1
Authority
EP
European Patent Office
Prior art keywords
tank
bath
electrolysis
metal
ppm
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
EP86420077A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0197867A1 (fr
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.)
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 AT86420077T priority Critical patent/ATE38693T1/de
Publication of EP0197867A1 publication Critical patent/EP0197867A1/fr
Application granted granted Critical
Publication of EP0197867B1 publication Critical patent/EP0197867B1/fr
Expired legal-status Critical Current

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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 subsequent contributions of salts, intended to compensate for the losses caused by the extraction of the metal, and the common impurities contained in the halide of the metal to be produced such as, for example, iron , aluminum, oxygen, etc ... constitute a permanent source of pollution in these various impurities.
  • the purity can be improved by a prior electrolytic treatment called pre-electrolysis, during which between two electrodes immersed in the molten bath which does not yet contain halides of the metal to be deposited, a DC voltage slightly lower than that necessary to obtain the easiest reduction of the alkali or alkaline earth halide.
  • the density of the resulting current is a function of the concentrations of elements to be eliminated; but it is usually very low, in the order of 10 -3 A / cm 2, and it still decreased during the operation. Therefore, the duration of the preelectrolysis is very long.
  • the invention therefore applies to electrolysis cells in which the metal cell containing the bath of molten salts is devoid of internal refractory lining and is therefore in direct contact with said bath.
  • the metal which constitutes the tank is chosen from those of metals having good chemical resistance to the salts and halides of the metals to be produced. It can in particular be nickel and its alloys or more simply a stainless steel.
  • This tank is connected in a known manner to an electrical circuit so that a bias current is established in contact with the bath and the tank.
  • the applied potential makes it possible to establish a bias current with a density of between 0.5 10 -4 and 5 10 -4 A / cm 2 .
  • a bias current with a density of between 0.5 10 -4 and 5 10 -4 A / cm 2 .
  • the electrolysis carried out according to the usual voltage and current density criteria between anode and cathode leads to a metal of improved purity compared to that obtained without polarization of the cell; this improvement being obtained at the expense of a slight loss of the highly polluted metal deposited on the wall of the tank.
  • the density range used is explained by the fact that below 0.5 10 -4 A / cm 2 the polarization is no longer sufficiently effective and that above 5.10- 4 A / cm 2 it is turns out to be superfluous because it leads to an unnecessary loss of metal without appreciable improvement in the purity of the metal collected at the cathode.
  • the Applicant has also found that it is possible to impose on the cell a cathodic potential with respect to the anode, but with a higher current density, as a means of preelectrolysis at the start of the cell. Indeed, if before starting the actual electrolysis between anode and cathode, and while the molten bath is loaded with halide of the metal to be produced, the cell is polarized so as to have a current density between 1 . 10 - 2 A / cm 2 , and 5.10- 2 A / cm 2 , there occurs on the walls of the tank a deposit of metal polluted in oxygen and in foreign metallic elements less electro-negative than the metal to be produced which are this quickly eliminated from the bath.
  • the current density claimed range reflects the fact that below 1.10- 2 A / cm 2 the duration of the operation becomes prohibitive and that below 2 5.10 A / cm 2 metal losses become larger without significant benefit for purification.
  • the deposit of metal on the cell ultimately only represents a very minimal thickness (a few tenths of a millimeter), and it is not a problem for subsequent electrolysis, at least as long as the polarization conditions of the cell mentioned higher are observed: current density between 0.5 10 -4 A / cm 2 510-4 A / cm 2 .
  • the present invention finds its application in the manufacture by continuous electrolysis in bath of molten salts of metals with low oxygen and foreign metal content.

Landscapes

  • 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)
  • Manufacture And Refinement Of Metals (AREA)
EP86420077A 1985-03-19 1986-03-17 Procédé d'amélioration de la pureté des métaux de transition obtenus par électrolyse de leurs halogénures en bain de sels fondus Expired EP0197867B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86420077T ATE38693T1 (de) 1985-03-19 1986-03-17 Verfahren zur erhoehung der reinheit von uebergangsmetallen, die durch elektrolyse aus ihren geschmolzenen halogeniden gewonnen werden.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8504596A FR2579230B1 (fr) 1985-03-19 1985-03-19 Procede d'amelioration de la purete des metaux de transition obtenus par electrolyse de leurs halogenures en bain de sels fondus
FR8504596 1985-03-19

Publications (2)

Publication Number Publication Date
EP0197867A1 EP0197867A1 (fr) 1986-10-15
EP0197867B1 true EP0197867B1 (fr) 1988-11-17

Family

ID=9317652

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86420077A Expired EP0197867B1 (fr) 1985-03-19 1986-03-17 Procédé d'amélioration de la pureté des métaux de transition obtenus par électrolyse de leurs halogénures en bain de sels fondus

Country Status (7)

Country Link
US (1) US4675084A (enrdf_load_stackoverflow)
EP (1) EP0197867B1 (enrdf_load_stackoverflow)
JP (1) JPS61217592A (enrdf_load_stackoverflow)
AT (1) ATE38693T1 (enrdf_load_stackoverflow)
CA (1) CA1268446A (enrdf_load_stackoverflow)
DE (1) DE3661203D1 (enrdf_load_stackoverflow)
FR (1) FR2579230B1 (enrdf_load_stackoverflow)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102127656B (zh) * 2010-01-13 2013-07-10 中国科学院过程工程研究所 一种液相氧化分解钒渣的方法
CN101845549A (zh) * 2010-06-18 2010-09-29 中南大学 一种石煤清洁转化方法
CN104018190B (zh) * 2014-06-17 2016-06-08 北京工业大学 一种回收废硬质合金的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US476914A (en) * 1892-06-14 Myrthil bernard and ernest bernard
US2783195A (en) * 1955-04-29 1957-02-26 Horizons Titanium Corp Control of corrosion in reaction vessels
US2937128A (en) * 1956-07-25 1960-05-17 Horizons Titanium Corp Electrolytic apparatus
US2975111A (en) * 1958-03-19 1961-03-14 New Jersey Zinc Co Production of titanium
US3082159A (en) * 1960-03-29 1963-03-19 New Jersey Zinc Co Production of titanium

Also Published As

Publication number Publication date
JPS61217592A (ja) 1986-09-27
EP0197867A1 (fr) 1986-10-15
FR2579230A1 (fr) 1986-09-26
ATE38693T1 (de) 1988-12-15
US4675084A (en) 1987-06-23
DE3661203D1 (en) 1988-12-22
CA1268446A (fr) 1990-05-01
JPH0213034B2 (enrdf_load_stackoverflow) 1990-04-03
FR2579230B1 (fr) 1990-05-25

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