EP0197867A1 - Process for improving the purity of transition metals obtained by electrolysis of their halides in molten salts baths - Google Patents
Process for improving the purity of transition metals obtained by electrolysis of their halides in molten salts baths Download PDFInfo
- Publication number
- EP0197867A1 EP0197867A1 EP86420077A EP86420077A EP0197867A1 EP 0197867 A1 EP0197867 A1 EP 0197867A1 EP 86420077 A EP86420077 A EP 86420077A EP 86420077 A EP86420077 A EP 86420077A EP 0197867 A1 EP0197867 A1 EP 0197867A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- bath
- tank
- electrolysis
- metal
- halides
- 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.)
- Granted
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
-
- 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 concluded Nationale Su Southerneure d'Electrochimie et d'Electrométallurgie de Grenoble, relates to a process for improving the purity of transition metals obtained by continuous electrolysis from of their halides dissolved in a bath of molten salts constituted by alkali and / or alkaline-earth halides.
- 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 current which results therefrom is a function of the concentrations of elements to be eliminated: but it is generally very low, of the order of 10 -3 A / cm 2 , and it decreases further 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 transition metals. 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 tank; this. improvement being obtained at the expense of a slight loss of 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 it s 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 'and 5.10-' 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 therefore quickly eliminated from the bath.
- the present invention finds its application in the manufacture by continuous electrolysis in a bath of molten salts of transition metals with a low oxygen content and of foreign metallic elements.
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)
Abstract
Description
La présente invention, qui résulte de travaux réalisés dans les laboratoires de l'Ecole Nationale Supérieure d'Electrochimie et d'Electrométallurgie de Grenoble, est relative à un procédé d'amélioration de la pureté des métaux de transition obtenus par électrolyse en continu à partir de leurs halogénures dissous en bain de sels fondus constitués par des halogénures alcalins et/ou alcalino-terreux.The present invention, which results from work carried out in the laboratories of the Ecole Nationale Supérieure d'Electrochimie et d'Electrométallurgie de Grenoble, relates to a process for improving the purity of transition metals obtained by continuous electrolysis from of their halides dissolved in a bath of molten salts constituted by alkali and / or alkaline-earth halides.
Dans ce qui va suivre :
- 1. on entend par métaux de transition, des métaux généralement polyvalents ayant un point de fusion supérieur à 1400°C et possédant une affinité relativement élevée pour l'oxygène quand ils sont chauffés tels que ceux des colonnes IVB, VB, VIB de la classification périodique de Mendeleev, et notamment le titane, le zirconium, le hafnium, le tantale, le niobium, et le vanadium.
- 2. on entend par électrolyse en continu, un procédé dans lequel le dépôt et l'extraction du métal à la cathode et le dégagement d'halogène à l'anode sont en permanence compensés par un apport d'halogénure frais destiné à maintenir approximativement constante la teneur en métal à produire dissous dans le bain.
- 1. transition metals are understood to mean generally polyvalent metals having a melting point above 1400 ° C. and having a relatively high affinity for oxygen when they are heated, such as those of columns IVB, VB, VIB of the classification of Mendeleev, and in particular titanium, zirconium, hafnium, tantalum, niobium, and vanadium.
- 2. continuous electrolysis is understood to mean a process in which the deposition and extraction of the metal at the cathode and the release of halogen at the anode are permanently compensated by an addition of fresh halide intended to keep approximately constant the content of metal to be produced dissolved in the bath.
Il est connu que les bains d'halogénures alcalins et/ou alcalino-terreux fondus, utilisés pour l'élaboration des métaux de transition à partir de leurs halogénures contiennent toujours, quelles que soient les précautions prises au cours de leur préparation, des impuretés métalliques et métallïdiques. En particulier, du fait de l'hygrosco- picité plus ou moins prononcée de leurs constituants, l'oxygène est toujours présent soit en solution, soit sous forme d'oxydes plus ou moins en suspension. L'utflisation directe de ces bains conduit, au moins pendant un temps plus ou moins long, à des métaux pollués en impuretés métalliques moins électronégatives que le métal à produire et surtout en oxygène. Par ailleurs, dans le cas des procédés continus, les apports ultérieurs de sels, destinés à compenser les pertes entraînées par l'extraction du métal et les impuretés courantes contenues dans l'halogénure du métal à produire telles que, par exemple, le fer, l'aluminium, l'oxygène, etc..., consitutuent une source permanente de pollution en ces diverses impuretés.It is known that the molten alkali and / or alkaline earth halide baths, used for the preparation of transition metals from their halides always contain, regardless of the precautions taken during their preparation, metallic impurities and metallides. In particular, due to the more or less pronounced hygroscopicity of their constituents, oxygen is always present either in solution or in the form of more or less suspended oxides. The direct use of these baths leads, at least for a more or less long time, to metals polluted in metallic impurities which are less electronegative than the metal to be produced and especially in oxygen. Furthermore, in the case of continuous processes, 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.
En ce qui concerne le bain initial lui-même, la pureté peut être améliorée par un traitement électrolytique préalable appelé préélectrolyse, au cours duquel on établit entre deux électrodes plongeant dans le bain fondu ne contenant pas encore d'halogénures du métal à déposer, une tension continue légèrement inférieure à celle nécessaire pour obtenir la décomposition de l'halogénure alcalin ou alcalino-terreux le plus facile à réduire. La densité du courant qui en résulte, est fonction des concentrations en éléments à éliminer: mais elle est en général très faible, de l'ordre de 10-3 A/cm2, et elle diminue encore au cours de l'opération. De ce fait, la durée de la préélectrolyse est très longue.As regards the initial bath itself, 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 current which results therefrom is a function of the concentrations of elements to be eliminated: but it is generally very low, of the order of 10 -3 A / cm 2 , and it decreases further during the operation. Therefore, the duration of the preelectrolysis is very long.
Une technique de préélectrolyse plus performante a été proposée dans le brevet USP 2 782 156.A more efficient pre-electrolysis technique has been proposed in USP 2,782,156.
Elle consiste toujours à établir entre des électrodes plongeant dans le bain une tension continue, mais dans ce cas le bain est chargé en halogénure du métal à produire et la tension imposée est choisie supérieure à celles nécessaires pour effectuer le dépôt du métal en question à la cathode et suffisante pour effectuer la décomposition de l'eau et des sels et oxydes des éléments polluants et le dépôt desdits éléments à la cathode. Cette préélectrolyse. à intensité constante est maintenue pendant un temps suffisant pour s'assurer que la majeure partie de l'eau et des éléments polluants a été éliminée du bain de sels ainsi qu'une petite partie du métal de transition à produire. Etant donné que la densité de courant est au moins égale à la moitié de celle utilisée pour l'électrolyse proprement dite, c'est-à-dire 0,2 à 0,255 A/cm2 dans le cas du brevet, la durée de préélectrolyse est relativement courte par exemple d'une 1/2 heure dans les conditions de l'exemple 1.It always consists in establishing between electrodes immersing in the bath a continuous tension, but in this case the bath is loaded with halide of the metal to be produced and the imposed tension is chosen higher than those necessary to deposit the metal in question at the cathode and sufficient to effect the decomposition of water and the salts and oxides of the polluting elements and the deposition of said elements at the cathode. This preelectrolysis. at constant intensity is maintained for a sufficient time to ensure that the major part of the water and of the polluting elements has been removed from the salt bath as well as a small part of the transition metal to be produced. Since the current density is at least equal to half of that used for the actual electrolysis, that is to say 0.2 to 0.255 A / cm 2 in the case of the patent, the duration of preelectrolysis is relatively short, for example 1/2 hour under the conditions of Example 1.
Bien que cette technique représente un progrès substantiel par rapport à la précédente, elle a l'inconvénient de ne s'appliquer encore qu'aux opérations discontinues dans lesquelles le bain, une fois purifié, est épuisé en métal de transition, et doit alors être ramené à sa composition initiale par ajout ou élimination de sels, rechargé en halogénure du métal à produire et soumis à nouveau au traitement de purification.Although this technique represents a substantial improvement over the previous one, it has the disadvantage of still only being applied to batch operations in which the bath, once purified, is depleted of transition metal, and must then be reduced to its initial composition by addition or elimination of salts, recharged with halide of the metal to be produced and subjected again to the purification treatment.
C'est pourquoi la demanderesse ayant pour but d'améliorer davantage la pureté des métaux de transition obtenus par électrolyse de leurs halogénures, a mis au point un procédé de purification applicable aux opérations continues, c'est-à-dire non seulement dans la période initiale, mais encore tout au long de la production comportant en particulier des apports plus ou moins continus de sels et d'halogénure du métal à produire.This is why the applicant, with the aim of further improving the purity of the transition metals obtained by electrolysis of their halides, has developed a purification process applicable to continuous operations, that is to say to say not only in the initial period, but also throughout the production comprising in particular more or less continuous contributions of salts and halide of the metal to be produced.
Les recherches entreprises dans ce sens ont abouti à la mise a point, dans des cellules comportant d'une part une cuve à paroi interne métallique contenant le bain fondu, d'autre part un couvercle assurant l'étanchéité de la cuve, isolé électriquement de la cuve et présentant divers orifices permettant, entre autre, le passage des dispositifs anodique et cathodique plongeant dans le bain. l'alimentation de ce bain en halogénure du métal à produire et l'extraction de l'halogène dégagé à l'anode, d'un procédé caractérisé en ce qu'on impose en permanence à la cuve un potentiel cathodique par rapport au dispositif anodique.The research undertaken in this direction led to the development, in cells comprising on the one hand a tank with internal metal wall containing the molten bath, on the other hand a cover ensuring the tightness of the tank, electrically insulated from the tank and having various orifices allowing, among other things, the passage of the anode and cathode devices immersed in the bath. the supply of this metal halide bath to the metal to be produced and the extraction of the halogen released at the anode, a process characterized in that cathode potential is permanently imposed on the tank relative to the anode device .
L'invention s'applique donc à des cellules d'électrolyse dans lesquelles la cuve métallique contenant le bain de sels fondus est dépourvue de garnissage réfractaire interne et se trouve donc en contact direct avec ledit bain. Le métal qui constitue la cuve est choisi parmi ceux des métaux ayant une bonne tenue chimique aux sels et aux halogénures des métaux de transition. Ce peut être notamment le nickel et ses alliages ou plus simplement un acier inoxydable.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 transition metals. It can in particular be nickel and its alloys or more simply a stainless steel.
Cette cuve est reliée de manière connue à un circuit électrique de manière qu'il s'établisse un courant de polarisation au contact du bain et de la- cuve.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.
De préférence, le potentiel appliqué permet d'établir un courant de polarisation de densité comprise entre 0,5 10-4 et 5 10-4 A/cm2. Dans ces conditions, on constate que l'électrolyse menée suivant les critères de tension et de densité de courant habituels entre anode et cathode. conduit à un métal de pureté améliorée par rapport à celui obtenu sans polarisation de la cuve; cette. amélioration étant obtenue aux dépens d'une légère perte de métal fortement pollué déposé sur la paroi de la cuve.Preferably, 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 . Under these conditions, it can be seen that 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 tank; this. improvement being obtained at the expense of a slight loss of highly polluted metal deposited on the wall of the tank.
La fourchette de densité retenue s'explique du fait qu'au-dessous de 0,5 10-4 A/cm2 la polarisation n'est plus suffisamment efficace et qu'au-dessus de 5.10-4 A/cm elle s'avère superflue car elle conduit à une perte de métal inutile sans amélioration notable de la pureté du métal recueilli à la cathode.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 it s 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.
La demanderesse a constaté en outre qu'on pouvait imposer à la cuve un potentiel cathodique par rapport à l'anode, mais avec une densité de courant plus élevée, comme moyen de préélectrolyse au démarrage de la cellule. En effet, si avant de démarrer l'électrolyse proprement dite entre anode et cathode, et alors que le bain fondu est chargé en halogénure du métal à produire, on polarise la cuve de manière à avoir une densité de courant entre 1.10-2 A/cm' et 5.10-' A/cm2, il se produit sur les parois de la cuve un dépôt de métal pollué en oxygène et en élémentsmétalliques étrangers moins électro-négatifs que le métal à produire qui sont de ce fait rapidement éliminés du bain.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 'and 5.10-' 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 therefore quickly eliminated from the bath.
La fourchette de densité de courant revendiquée tient compte du fait qu'au-dessous de 1.10-2 A/cm' la durée de l'opération devient prohibitive et qu'au-dessus de 5.10-2 A/cm' les pertes de métal deviennent plus importantes sans bénéfice notable pour la purification. Le dépôt de métal sur la cuve ne représente en définitive qu'une épaisseur très minime (quelques dixièmes de millimètres), et il n'est pas gênant pour l'électrolyse ultérieure, tout au moins tant que les conditions de polarisation de la cuve mentionnées plus haut sont respectées : densité de courant comprise entre 0,5 10-4 A/cm2 5 10-4 A/cm2.The range of current density claimed recognizes that below 1.10- 2 A / cm length of the operation becomes prohibitive and that above 5.10 2 A / cm 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 5 10 -4 A / cm 2 .
L'invention peut être illustrée à l'aide des exemples d'application suivants :The invention can be illustrated using the following application examples:
Dans une cellule en acier inoxydable réfractaire munie d'un dispositif anodique et d'une cathode, on a chargé 200 kg de mélange équimolésulaire NaCI, KCI préalablement séché à 500° sous vide; après fusion à 750°C et introduction de 11,5 kg de HfCl4, on a procédé aux 3 électrolyses suivantes, au cours desquelles la teneur en hafnium dissous dans le bain était maintenue constante grâce à une addition de chlorure à raison de une mole pour 4 Faradays.In a refractory stainless steel cell provided with an anode device and a cathode, 200 kg of NaCl, KCI equimolesular mixture, previously dried at 500 ° under vacuum, were charged; after melting at 750 ° C. and introduction of 11.5 kg of HfCl 4 , the following 3 electrolyses were carried out, during which the content of hafnium dissolved in the bath was kept constant by adding chloride at the rate of one mole for 4 Faradays.
-
1. Une électrolyse de 1/2 heure à 200 A sur une cathode de 400 cm2 (densité de courant 0,5 A/cm') a fourni 160 g de Hafnium métal, contenant les impuretés principales suivantes :ce qui indique un bain fortement pollué.1. 1/2 hour electrolysis at 200 A on a 400 cm 2 cathode (current density 0.5 A / cm ') provided 160 g of Hafnium metal, containing the following main impurities:
which indicates a heavily polluted bath. - 2. On a alors procédé à une électrolyse de 6 h à 200 A. en utlisant la cuve elle-même comme cathode (densité de courant 2 10-2 A/cm2), ce qui correspond au dépôt de 2 kg de hafnium métal sur la paroi de la cuve, soit une épaisseur moyenne de l'ordre de 0,15 mm.2. We then proceeded to an electrolysis of 6 h at 200 A. using the cell itself as a cathode (current density 2 10- 2 A / cm 2 ), which corresponds to the deposit of 2 kg of hafnium metal on the wall of the tank, ie an average thickness of the order of 0.15 mm.
-
3. Une nouvelle électrolyse de 1/2 h à 200 A sur une cathode de 400 cm2 a alors fourni 163 g de métal répondant à l'analyse suivante :ce qui indique une excellente purification du bain. Avec le procédé de préélectrolyse sans dépôt de métal sur la cuve, ce résultat n'aurait pu être atteint en moins de 1000 h.3. A new 1/2 hour electrolysis at 200 A on a 400 cm 2 cathode then provided 163 g of metal corresponding to the following analysis:
which indicates excellent purification of the bath. With the pre-electrolysis process without metal deposition on the tank, this result could not have been achieved in less than 1000 h.
Toujours avec la même cellule après la troisième électrolyse décrite dans l'exemple 1, on a procédé à une quatrième électrolyse de 1/2 h à 200 A. sur cathode de 400 cm2, mais en imposant cette fois à la cuve un courant de polarisation cathodique de 2 A. soit une densité de courant de 2 10-' A/cm2; on a alors recueilli 162 g de métal ne contenant plus que 130 ppm d'oxygène, toutes les autres impuretés étant maintenant inférieures à 10 ppm, mis à part le zirconium : 0,8 %.Still with the same cell after the third electrolysis described in example 1, a fourth electrolysis of 1/2 h at 200 A. was carried out on a 400 cm 2 cathode, but this time imposing on the cell a current of cathodic polarization of 2 A., ie a current density of 2 10- 'A / cm 2 ; 162 g of metal were then collected containing no more than 130 ppm of oxygen, all the other impurities now being less than 10 ppm, apart from the zirconium: 0.8%.
Au cours des électrolyses ultérieures, et dans les mêmes conditions, on a pu déposer 40 kg de Hf à moins de 200 ppm d'oxygène, malgré une alimentation continue en HfCl4 et plusieurs rajouts de sel.During subsequent electrolysis, and under the same conditions, 40 kg of Hf could be deposited at less than 200 ppm of oxygen, despite a continuous supply of HfCl 4 and several additions of salt.
La présente invention trouve son application dans la fabrication par électrolyse continue en bain de sels fondus de métaux de transition à faible teneur en oxygène et en éléments métalliques étrangers.The present invention finds its application in the manufacture by continuous electrolysis in a bath of molten salts of transition metals with a low oxygen content and of foreign metallic elements.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT86420077T ATE38693T1 (en) | 1985-03-19 | 1986-03-17 | PROCESSES FOR INCREASING THE PURITY OF TRANSITION METALS OBTAINED FROM THEIR MOLTEN HALOGENS BY ELECTROLYSIS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8504596 | 1985-03-19 | ||
| FR8504596A FR2579230B1 (en) | 1985-03-19 | 1985-03-19 | PROCESS FOR IMPROVING THE PURITY OF THE TRANSITION METALS OBTAINED BY ELECTROLYSIS OF THEIR HALIDES WITH BATH MOLTEN |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0197867A1 true EP0197867A1 (en) | 1986-10-15 |
| EP0197867B1 EP0197867B1 (en) | 1988-11-17 |
Family
ID=9317652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP86420077A Expired EP0197867B1 (en) | 1985-03-19 | 1986-03-17 | Process for improving the purity of transition metals obtained by electrolysis of their halides in molten salts baths |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4675084A (en) |
| EP (1) | EP0197867B1 (en) |
| JP (1) | JPS61217592A (en) |
| AT (1) | ATE38693T1 (en) |
| CA (1) | CA1268446A (en) |
| DE (1) | DE3661203D1 (en) |
| FR (1) | FR2579230B1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102127656B (en) * | 2010-01-13 | 2013-07-10 | 中国科学院过程工程研究所 | Method for decomposing vanadium slag by liquid phase oxidation |
| CN101845549A (en) * | 2010-06-18 | 2010-09-29 | 中南大学 | Method for cleaning and converting stone coal |
| CN104018190B (en) * | 2014-06-17 | 2016-06-08 | 北京工业大学 | A kind of method that reclaims hard alloy scraps |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3082159A (en) * | 1960-03-29 | 1963-03-19 | New Jersey Zinc Co | Production of titanium |
Family Cites Families (4)
| 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 |
-
1985
- 1985-03-19 FR FR8504596A patent/FR2579230B1/en not_active Expired - Fee Related
-
1986
- 1986-02-18 US US06/829,937 patent/US4675084A/en not_active Expired - Lifetime
- 1986-03-14 JP JP61056744A patent/JPS61217592A/en active Granted
- 1986-03-17 AT AT86420077T patent/ATE38693T1/en active
- 1986-03-17 CA CA000504243A patent/CA1268446A/en not_active Expired - Fee Related
- 1986-03-17 DE DE8686420077T patent/DE3661203D1/en not_active Expired
- 1986-03-17 EP EP86420077A patent/EP0197867B1/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3082159A (en) * | 1960-03-29 | 1963-03-19 | New Jersey Zinc Co | Production of titanium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0213034B2 (en) | 1990-04-03 |
| DE3661203D1 (en) | 1988-12-22 |
| FR2579230B1 (en) | 1990-05-25 |
| ATE38693T1 (en) | 1988-12-15 |
| JPS61217592A (en) | 1986-09-27 |
| EP0197867B1 (en) | 1988-11-17 |
| US4675084A (en) | 1987-06-23 |
| FR2579230A1 (en) | 1986-09-26 |
| CA1268446A (en) | 1990-05-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0570308B1 (en) | Alloys of metals with high melting points, suitable for transformation into homogeneous and pure ingost, and preparation process of these alloys | |
| MXPA04008887A (en) | Reduction of metal oxides in an electrolytic cell. | |
| CH410441A (en) | Refining process for silicon and germanium | |
| CH679158A5 (en) | ||
| EP0230411A1 (en) | Method for producing calcium or calcium alloys with high purity | |
| EP0197867B1 (en) | Process for improving the purity of transition metals obtained by electrolysis of their halides in molten salts baths | |
| US2782156A (en) | Purification of fused salt electrolytes | |
| FR2546186A1 (en) | DEVICE FOR THE ELECTROLYTIC TREATMENT OF METAL TAPES | |
| EP0005674B1 (en) | Process of manufacturing a dimensionally stable anode | |
| US3726772A (en) | Method for removing iron impurities contained in a salt bath for nitrogenation | |
| WO1987004193A1 (en) | Process for producing transition metal powders by electrolysis in baths of molten salts | |
| LU85359A1 (en) | DEVICE FOR THE ELECTROLYTIC TREATMENT OF METAL TAPES | |
| FR2680523A1 (en) | ELECTRODEPOSITION PROCESS. | |
| FR2480796A1 (en) | High purity silicon deposit formation - by electrolytic deposition from alkali (ne earth) metal halide melt contg. dissolved silicon | |
| RU2747058C1 (en) | Method for electrochemical precipitation of niobium coatings from bromide melts | |
| CA1193996A (en) | Process and apparatus for the recuperation of zinc from industrial wastes containing zinc | |
| US20210310140A1 (en) | Method for Producing Metal Titanium | |
| EP0267858B1 (en) | Process for manufacturing vanadium trichloride in an aqueous solution | |
| RU2797969C1 (en) | Method for electrolytic production of microsized silicon films from molten salts | |
| FR2739872A1 (en) | Electrolytically depositing zinc or zinc alloys on steel | |
| CH451638A (en) | Process for the deposition of refractory metals by electrolytic means | |
| CH381435A (en) | Tantalum electrolytic manufacturing process | |
| RU2368706C2 (en) | Cleaning method of molten chloride electrolyte for receiving of platinum metals | |
| EP0394154B1 (en) | Apparatus for the continuous production of a multivalent metal by electrolysis of a halide thereof dissolved in a molten bath | |
| EP0105896B1 (en) | Apparatus for continuous production of zinc electroplated sheet |
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 |
Kind code of ref document: A1 Designated state(s): AT BE CH DE GB IT LI LU NL SE |
|
| 17P | Request for examination filed |
Effective date: 19861031 |
|
| 17Q | First examination report despatched |
Effective date: 19880114 |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT BE CH DE GB IT LI LU NL SE |
|
| REF | Corresponds to: |
Ref document number: 38693 Country of ref document: AT Date of ref document: 19881215 Kind code of ref document: T |
|
| ITF | It: translation for a ep patent filed |
Owner name: ING. A. GIAMBROCONO & C. S.R.L. |
|
| GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) | ||
| REF | Corresponds to: |
Ref document number: 3661203 Country of ref document: DE Date of ref document: 19881222 |
|
| 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: CH Payment date: 19910213 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19910214 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: LU Payment date: 19910220 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: BE Payment date: 19910328 Year of fee payment: 6 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 19910331 Year of fee payment: 6 |
|
| EPTA | Lu: last paid annual fee | ||
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 19920317 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19920318 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Effective date: 19920331 Ref country code: CH Effective date: 19920331 Ref country code: BE Effective date: 19920331 |
|
| BERE | Be: lapsed |
Owner name: PECHINEY Effective date: 19920331 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19921001 |
|
| NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee | ||
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
| ITTA | It: last paid annual fee | ||
| EUG | Se: european patent has lapsed |
Ref document number: 86420077.9 Effective date: 19921005 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 19960220 Year of fee payment: 11 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Effective date: 19970317 |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: 732E |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20010314 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: 20010323 Year of fee payment: 16 |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
| 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: 20020317 |
|
| 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: 20021001 |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20020317 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050317 |