EP0402288A2 - Process for the separation of calcium and nitrogen from lithium - Google Patents

Process for the separation of calcium and nitrogen from lithium Download PDF

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Publication number
EP0402288A2
EP0402288A2 EP90420275A EP90420275A EP0402288A2 EP 0402288 A2 EP0402288 A2 EP 0402288A2 EP 90420275 A EP90420275 A EP 90420275A EP 90420275 A EP90420275 A EP 90420275A EP 0402288 A2 EP0402288 A2 EP 0402288A2
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Prior art keywords
lithium
calcium
alumina
separation
nitrogen
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EP90420275A
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German (de)
French (fr)
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EP0402288B1 (en
EP0402288A3 (en
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Guy Bernard
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Metaux Speciaux SA
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Metaux Speciaux SA
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B26/00Obtaining alkali, alkaline earth metals or magnesium
    • C22B26/10Obtaining alkali metals
    • C22B26/12Obtaining lithium

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Metallurgy (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Removal Of Specific Substances (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Secondary Cells (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

Process for separating calcium and nitrogen from lithium. <??>This process is characterised in that alumina is added to molten lithium so as to form aluminium nitride and calcium oxide, which are insoluble, and the said insoluble materials are separated off with heating to recover purified lithium. <??>It finds its application in the production of lithium of a quality which is particularly suitable for the manufacture of aluminium-lithium alloys and of electrical battery electrodes.

Description

La présente invention est relative à un procédé de séparation du calcium et de l'azote du lithium.The present invention relates to a process for the separation of calcium and nitrogen from lithium.

Le lithium métallique est généralement obtenu par électrolyse ignée de chlorure de lithium qui peut contenir des impuretés telles que le chlorure de calcium. Ce sel est partiellement dissocié par le courant électrique et se retrouve donc sous forme de calcium dans le métal obtenu où il peut atteindre une teneur de plusieurs centaines de ppm. Cet élément est particulièrement gênant quand le métal sert notamment a élaborer des alliages aluminium lithium car il tend à dégrader leurs caractéristiques mécaniques.
Par ailleurs, le lithium au cours de sa préparation est parfois mis au contact de l'air; comme il est particulièrement sensible à l'action de l'azote, il a tendance à former des nitrures dont la teneur peut atteindre également plusieurs centaines de ppm. Or, ces nitrures sont des composés très durs dont la présence dans les alliages va être la cause d'ennuis non seulement au niveau de leurs propriétés mais aussi lors de leur mise en forme du fait de leur action abrasive sur l'outillage utilisé: lingotière de coulée, cylindre de laminoir, matrice d'extrusion, etc. En particulier, ces nitrures fragilisent les feuilles de lithium utilisées comme électrodes dans les batteries électriques.
Metallic lithium is generally obtained by igneous electrolysis of lithium chloride which can contain impurities such as calcium chloride. This salt is partially dissociated by the electric current and is therefore found in the form of calcium in the metal obtained where it can reach a content of several hundred ppm. This element is particularly troublesome when the metal is used in particular to develop lithium aluminum alloys because it tends to degrade their mechanical characteristics.
Furthermore, lithium during its preparation is sometimes brought into contact with air; as it is particularly sensitive to the action of nitrogen, it tends to form nitrides whose content can also reach several hundred ppm. However, these nitrides are very hard compounds whose presence in alloys will cause trouble not only in terms of their properties but also during their shaping due to their abrasive action on the tools used: ingot mold casting, rolling mill cylinder, extrusion die, etc. In particular, these nitrides weaken the lithium sheets used as electrodes in electric batteries.

D'où la nécessité de débarrasser le lithium du calcium et de l'azote qu'il contient ou tout au moins d'abaisser la teneur en ces impuretés à une valeur généralement inférieure à 100 ppm avant de l'utiliser à l'état de métal ou d'alliage.Hence the need to rid the lithium of the calcium and nitrogen it contains or at least to lower the content of these impurities to a value generally less than 100 ppm before using it in the state of metal or alloy.

En ce qui concerne la séparation du calcium, elle n'est pas possible par filtration car sa solubilité dans le lithium est relativement grande. De même si la distillation s'avère être un procédé convenable pour épurer le lithium en sodium et en potassium, par contre elle est peu efficace vis à vis des éléments alcalinoterreux et notamment du calcium.
Certes, on sait que certains composés du calcium tels que l'oxyde CaO sont insolubles dans le lithium mais, a priori, on peut penser que vouloir oxyder le calcium in situ va provoquer également une oxydation du lithium. En fait, on a constaté que l'oxygène introduit dans le lithium avait tendance à se fixer préférentiellement sur le calcium. Aussi en ajoutant une quantité d'oxygène calculée pour fixer la totalité du calcium présent et en filtrant ensuite le lithium, il est possible d'effectuer une épuration en calcium jusqu'à des teneurs compatibles avec les spécifications des fabricants d'aluminium-lithium.
Il existe plusieurs façons d'introduire l'oxygène dans le lithium.
- soit en faisant barboter de l'oxygène gazeux dans le lithium liquide, mais cette méthode n'est pas très commode car la réaction peut être localement violente et risque d'entraîner rapidement le colmatage de la tuyauterie d'amenée de l'oxygène par l'oxyde de lithium.
-soit en ajoutant de l'oxyde de lithium dans le lithium fondu de manière à produire la réaction suivante:
Li₂O+Ca → CaO + 2 Li
Cette méthode est très intéressante car elle réalise l'épuration sans entraîner d'autres pollutions. L'oxyde de lithium n'est cependant pas un produit commercial et il faut donc d'abord le produire, ce qui grève les frais d'épuration.
As regards the separation of calcium, it is not possible by filtration because its solubility in lithium is relatively high. Similarly, if the distillation turns out to be a suitable process for purifying lithium into sodium and potassium, on the other hand it is not very effective with respect to alkaline earth elements and in particular calcium.
Admittedly, we know that certain calcium compounds such as the oxide CaO are insoluble in lithium but, a priori, we can think that wanting to oxidize calcium in situ will also cause oxidation of lithium. In fact, it has been found that the oxygen introduced into the lithium tends to bind preferentially to the calcium. Also by adding an amount of oxygen calculated to fix all the calcium present and then filtering the lithium, it is possible to carry out a calcium purification up to contents compatible with the specifications of the manufacturers of aluminum-lithium.
There are several ways to introduce oxygen into lithium.
- Either by bubbling gaseous oxygen into the liquid lithium, but this method is not very convenient because the reaction can be locally violent and risks quickly leading to clogging of the oxygen supply piping by lithium oxide.
or by adding lithium oxide to the molten lithium so as to produce the following reaction:
Li₂O + Ca → CaO + 2 Li
This method is very interesting because it performs the purification without causing other pollution. Lithium oxide is not, however, a commercial product and must therefore be produced first, which increases the cost of purification.

En outre, ces méthodes d'oxydation ne semblent pas apporter de solution à la séparation de l'azote du lithium sous forme de nitrure. En effet parmi les méthodes connues, on peut citer par exemple celle qui est exposée dans le brevet US 4781756 et qui consiste à ajouter une quantité stoechiométrique d'aluminium de manière à obtenir la réaction Li₃N + Al →AlN + 3Li puis à séparer le nitrure d'aluminium formé. Or, ce n'est pas l'aluminium qui permettra d'oxyder le calcium.
D'où les études qui ont été entreprises par la demanderesse pour trouver une autre solution qui convienne simultanément à l'élimination des deux types d'impuretés et dans la mesure du possible en employant un seul réactif.
In addition, these oxidation methods do not seem to provide a solution to the separation of nitrogen from lithium in the form of nitride. Indeed, among the known methods, there may be mentioned, for example, that which is set out in US Pat. of formed aluminum. However, it is not aluminum that will oxidize calcium.
Hence the studies which have been undertaken by the applicant to find another solution which is suitable simultaneously for the elimination of the two types of impurities and as far as possible by employing a single reagent.

Ces études ont abouti à un procédé caractérisé en ce que l'on ajoute au lithium de l'alumine divisée de manière à former du nitrure d'aluminium et de l'oxyde de calcium insolubles et on sépare à chaud lesdits insolubles pour récupérer le lithium liquide purifié.These studies have resulted in a process characterized in that insoluble alumina is added to the lithium so as to form insoluble aluminum nitride and calcium oxide and the said insoluble matter is hot separated to recover the lithium. purified liquid.

Dans ces conditions, une partie du lithium réduit l'oxyde d'aluminium et se transforme en oxyde de lithium qui va servir à oxyder le calcium suivant la réaction décrite plus haut. Par ailleurs, l'aluminium qui s'est formé lors de la réduction de l'alumine par le lithium va réagir avec le nitrure de lithium pour donner le nitrure d'aluminium comme dans l'us 4781756.Under these conditions, part of the lithium reduces the aluminum oxide and transforms into lithium oxide which will be used to oxidize the calcium according to the reaction described above. Furthermore, the aluminum which is formed during the reduction of alumina by lithium will react with the lithium nitride to give the aluminum nitride as in us 4781756.

L'oxyde de calcium et le nitrure d'aluminium insolubles peuvent alors être séparés en même temps du lithium liquide. On réalise ainsi, avec un seul réactif: l'alumine, l'élimination simultanée des deux impuretés du lithium.
La petite quantité d'aluminium qui peut rester dans le lithium est sans inconvénients notamment s'il sert à l'élaboration des alliages aluminium-lithium.
Par ailleurs, l'alumine est un produit très courant que l'on peut se procurer dans un état de grande pureté et sous forme suffisamment divisée pour réagir rapidement avec le lithium.
The insoluble calcium oxide and aluminum nitride can then be separated from the liquid lithium at the same time. Thus, with a single reagent: alumina, the two lithium impurities are eliminated simultaneously.
The small amount of aluminum which can remain in lithium is without disadvantages, in particular if it is used for the development of aluminum-lithium alloys.
Furthermore, alumina is a very common product which can be obtained in a state of high purity and in a sufficiently divided form to react quickly with lithium.

Les quantités d'alumine à mettre en oeuvre dépendront des quantités de calcium et d'azote présentes dans le lithium, mais il faut tenir compte du fait qu'elles sont cumulatives, une même fraction d'alumine servant simultanément à l'élimination des deux impuretés suivant les réactions successives suivantes:
Al₂O₃ + 6 Li → 3Li₂O + 2 Al
3Li₂O + 3 Ca → 3 CaO + 6 L1
2Li3N + 2 Al → 2 AlN+6 Li
The quantities of alumina to be used will depend on the quantities of calcium and nitrogen present in the lithium, but it must be taken into account that they are cumulative, the same fraction of alumina serving simultaneously for the elimination of the two impurities according to the following successive reactions:
Al₂O₃ + 6 Li → 3Li₂O + 2 Al
3Li₂O + 3 Ca → 3 CaO + 6 L1
2Li3N + 2 Al → 2 AlN + 6 Li

On constate que la quantité d'alumine suffisante pour éliminer 3 atomes grammes de calcium permettra également d'éliminer 2 atomes grammes d'azote.
On calcule donc la quantitè d'alumine convenable à partir de l'impureté qui en raison de sa teneur en exige la plus grande quantité, mais pratiquement on utilise des quantités de l'ordre de 10% supérieure en poids à la quantité calculée.
L'alumine mise en oeuvre a de préférence une granulométrie inférieure à 3 mm de manière à réagir le plus rapidement possible avec le lithium.
It is found that the amount of alumina sufficient to remove 3 grams of calcium atoms will also remove 2 grams of nitrogen atoms.
The quantity of suitable alumina is therefore calculated from the impurity which, because of its content, requires the greatest quantity, but practically quantities of the order of 10% greater by weight than the quantity calculated are used.
The alumina used preferably has a particle size of less than 3 mm so as to react as quickly as possible with the lithium.

Néanmoins, il est préférable pour faciliter les réactions de maintenir le bain de lithium fondu entre 400 et 500°C pendant 1 heure au moins avant d'effectuer la séparation des insolubles qui se sont formés.
Un perfectionnement du procédé consiste à agiter le mélange lithium-alumine pendant son maintien en température.
However, it is preferable to facilitate the reactions to maintain the molten lithium bath between 400 and 500 ° C for at least 1 hour before carrying out the separation of the insolubles which have formed.
An improvement of the process consists in agitating the lithium-alumina mixture while it is maintaining temperature.

La séparation du nitrure d'aluminium et de l'oxyde de calcium peut s'effectuer par tout moyen connu et, de préférence, par filtration. Cette opération s'effectue à chaud, mais pour assurer une meilleure tenue du matériel, il est préférable d'opérer à une température inférieure à celle du maintien c'est-à-dire entre 200 et 250°C.The separation of the aluminum nitride and the calcium oxide can be carried out by any known means and, preferably, by filtration. This operation is carried out hot, but to ensure better resistance of the equipment, it is preferable to operate at a temperature below that of the holding, that is to say between 200 and 250 ° C.

L'invention peut être illustrée à l'aide des exemples d'application suivants:The invention can be illustrated using the following application examples:

EXEMPLE 1EXAMPLE 1

A 100 kg de lithium contenant 250 ppm de calcium et 120 ppm d'azote, on a ajouté 50 grammes d'alumine de granulométrie 0,5 mm et porté l'ensemble à 480°C pendant 8 heures.
Après refroidissement et filtration à 220°C, le lithium ne contenait plus que 40 ppm de calcium et 60 ppm d'azote et sa teneur en aluminium était de 130 ppm.
To 100 kg of lithium containing 250 ppm of calcium and 120 ppm of nitrogen, 50 grams of alumina with a particle size of 0.5 mm were added and the whole was brought to 480 ° C. for 8 hours.
After cooling and filtration to 220 ° C., the lithium contained only 40 ppm of calcium and 60 ppm of nitrogen and its aluminum content was 130 ppm.

EXEMPLE.2EXAMPLE 2

A 100 kg de lithium contenant 200 ppm de calcium et 1500 ppm d'azote, on a ajouté 500 g d'alumine de granulométrie 1 mm et on a porté l'ensemble à 480°C pendant 8 heures.To 100 kg of lithium containing 200 ppm of calcium and 1500 ppm of nitrogen, 500 g of alumina with a particle size of 1 mm were added and the whole was brought to 480 ° C. for 8 hours.

Après filtration sur bougie PORAL classe 20 à 220°C, le lithium ne contenait plus que 20 ppm de calcium, 250 ppm d'azote et sa teneur en aluminium était de 50 ppm.After filtration on PORAL class 20 candle at 220 ° C, the lithium contained only 20 ppm of calcium, 250 ppm of nitrogen and its aluminum content was 50 ppm.

L'invention trouve son application dans l'obtention de lithium de qualité particulièrement apte à la fabrication d'alliages d'aluminium-lithium et d'électrodes de batteries électrique.The invention finds its application in obtaining quality lithium particularly suitable for the manufacture of aluminum-lithium alloys and electrodes of electric batteries.

Claims (6)

1) Procédé de séparation du calcium et de l' azote du lithium caractérisé en ce que l'on ajoute de l'alumine divisée au lithium fondu de manière à former du nitrure d'aluminium et de l'oxyde de calcium insolubles et que l'on sépare à chaud lesdits insolubles pour récupérer le lithium liquide purifié.1) Process for the separation of calcium and nitrogen from lithium, characterized in that divided alumina is added to molten lithium so as to form insoluble aluminum nitride and calcium oxide and that l 'said insoluble matter is hot separated to recover the purified liquid lithium. 2) Procédé selon la revendication 1 caractérisé en ce que l'alumine est ajoutée sous forme de poudre de granulométrie inférieure à 3 mm.2) Method according to claim 1 characterized in that the alumina is added in the form of powder with a particle size less than 3 mm. 3) Procédé selon la revendication 1 caractérisé en ce que le lithium et l'alumine sont maintenus entre 400 et 500°C pendant 1 heure au moins avant d'effectuer la séparation.3) Method according to claim 1 characterized in that the lithium and alumina are maintained between 400 and 500 ° C for at least 1 hour before carrying out the separation. 4) Procédé selon la revendication 1 caractérisé en ce que le lithium et l'alumine sont agités pendant la durée du maintien en température.4) Method according to claim 1 characterized in that the lithium and alumina are agitated for the duration of the temperature maintenance. 5) Procédé selon la revendication 1 caractérisé en ce que la séparation s'effectue par filtration.5) Method according to claim 1 characterized in that the separation is carried out by filtration. 6) Procédé selon la revendication 1 caractérisé en ce que la séparation s'effectue à une température comprise entre 200 et 250°C.6) Method according to claim 1 characterized in that the separation is carried out at a temperature between 200 and 250 ° C.
EP90420275A 1989-06-09 1990-06-07 Process for the separation of calcium and nitrogen from lithium Expired - Lifetime EP0402288B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8908144A FR2649416B1 (en) 1989-06-09 1989-06-09 PROCESS FOR SEPARATING CALCIUM AND LITHIUM NITROGEN
FR8908144 1989-06-09

Publications (3)

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EP0402288A2 true EP0402288A2 (en) 1990-12-12
EP0402288A3 EP0402288A3 (en) 1991-09-18
EP0402288B1 EP0402288B1 (en) 1994-09-21

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EP90420275A Expired - Lifetime EP0402288B1 (en) 1989-06-09 1990-06-07 Process for the separation of calcium and nitrogen from lithium

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US (1) US5019158A (en)
EP (1) EP0402288B1 (en)
JP (1) JPH0653952B2 (en)
AT (1) ATE111965T1 (en)
CA (1) CA2018409C (en)
DD (1) DD294973A5 (en)
DE (1) DE69012660T2 (en)
ES (1) ES2060116T3 (en)
FR (1) FR2649416B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU773007B2 (en) * 1999-05-07 2004-05-13 Bp Corporation North America Inc. Composite materials for membrane reactors
CN101642815A (en) * 2009-09-04 2010-02-10 黄启新 Method for preparing metal lithium at high temperature employing the electrical conductivity of molten slag

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106756105B (en) * 2016-12-19 2018-10-30 天齐锂业股份有限公司 The drop of nitride removes method in lithium metal or lithium alloy
CN107058761B (en) * 2016-12-19 2019-06-11 天齐锂业股份有限公司 The method that drop removes nitride in lithium metal or lithium alloy
US20190280292A1 (en) * 2018-03-08 2019-09-12 Seeo, Inc. Lithium metal foils with low defect density

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528032A (en) * 1984-01-10 1985-07-09 The United States Of America As Represented By The United States Department Of Energy Lithium purification technique
US4781756A (en) * 1987-07-02 1988-11-01 Lithium Corporation Of America Removal of lithium nitride from lithium metal

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3287109A (en) * 1963-05-31 1966-11-22 Dow Chemical Co Oxygen removal from alkali metals

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528032A (en) * 1984-01-10 1985-07-09 The United States Of America As Represented By The United States Department Of Energy Lithium purification technique
US4781756A (en) * 1987-07-02 1988-11-01 Lithium Corporation Of America Removal of lithium nitride from lithium metal

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF APPLIED CHEMISTRY vol. 13, Août 1963, LONDON UK pages 329 - 334; & BROOMFIELD: '"The purification of lithium by vacuum distillation" ' *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU773007B2 (en) * 1999-05-07 2004-05-13 Bp Corporation North America Inc. Composite materials for membrane reactors
CN101642815A (en) * 2009-09-04 2010-02-10 黄启新 Method for preparing metal lithium at high temperature employing the electrical conductivity of molten slag

Also Published As

Publication number Publication date
JPH0653952B2 (en) 1994-07-20
DD294973A5 (en) 1991-10-17
FR2649416B1 (en) 1991-11-29
CA2018409C (en) 1995-12-19
FR2649416A1 (en) 1991-01-11
EP0402288B1 (en) 1994-09-21
EP0402288A3 (en) 1991-09-18
ATE111965T1 (en) 1994-10-15
ES2060116T3 (en) 1994-11-16
DE69012660D1 (en) 1994-10-27
CA2018409A1 (en) 1990-12-09
DE69012660T2 (en) 1995-02-09
US5019158A (en) 1991-05-28
JPH0368792A (en) 1991-03-25

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