EP0090750B1 - Process for obtaining very high purity aluminium in entectic elements - Google Patents
Process for obtaining very high purity aluminium in entectic elements Download PDFInfo
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- EP0090750B1 EP0090750B1 EP83420054A EP83420054A EP0090750B1 EP 0090750 B1 EP0090750 B1 EP 0090750B1 EP 83420054 A EP83420054 A EP 83420054A EP 83420054 A EP83420054 A EP 83420054A EP 0090750 B1 EP0090750 B1 EP 0090750B1
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- ppm
- metal
- elements
- eutectic
- iron
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- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 21
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000004411 aluminium Substances 0.000 title claims 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 45
- 229910052742 iron Inorganic materials 0.000 claims abstract description 23
- 229910052751 metal Inorganic materials 0.000 claims abstract description 23
- 239000002184 metal Substances 0.000 claims abstract description 23
- 230000005496 eutectics Effects 0.000 claims abstract description 19
- 238000005204 segregation Methods 0.000 claims abstract description 19
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 17
- 239000010703 silicon Substances 0.000 claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 238000000746 purification Methods 0.000 claims description 17
- 239000013078 crystal Substances 0.000 claims description 15
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 11
- 229910052802 copper Inorganic materials 0.000 claims description 11
- 239000010949 copper Substances 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 11
- 239000012535 impurity Substances 0.000 claims description 8
- 238000002425 crystallisation Methods 0.000 claims description 5
- 230000008023 solidification Effects 0.000 claims description 5
- 238000007711 solidification Methods 0.000 claims description 5
- 229910001338 liquidmetal Inorganic materials 0.000 claims description 4
- 230000000750 progressive effect Effects 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 2
- 238000002844 melting Methods 0.000 claims description 2
- 238000005245 sintering Methods 0.000 claims description 2
- 239000003990 capacitor Substances 0.000 abstract description 6
- 150000002739 metals Chemical class 0.000 abstract description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 14
- 238000007792 addition Methods 0.000 description 7
- 230000008025 crystallization Effects 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000012452 mother liquor Substances 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 208000031968 Cadaver Diseases 0.000 description 1
- 229910001366 Hypereutectic aluminum Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011403 purification operation Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B21/00—Obtaining aluminium
- C22B21/06—Obtaining aluminium refining
Definitions
- the present invention relates to a process for obtaining very high purity aluminum in eutectic elements by segregation.
- the efficiency of the purification generally results in the value of the purification coefficient C o / Cg, where C s is the concentration of a given impurity in the pure product obtained, and C o is the concentration of the same impurity in the metal used, the higher this coefficient, the better the treatment efficiency.
- This process for obtaining very high purity aluminum that is to say containing at most 10 ppm in each of the iron and silicon eutectic elements, consists in subjecting an aluminum containing less than 200 ppm of the same elements to an operation of segregation, but characterized in that at least one eutectic element having a purification coefficient at least 7 in quantity is added to the molten aluminum, such that its concentration in the liquid after addition is between a minimum avoiding the mass crystallization and eutectics.
- the process of the invention uses an aluminum which is already very pure, for example which has already undergone a first purification which has made it possible to bring its content of total impurities to 200, and even up to 100 ppm or less.
- This aluminum may for example have a content of each of the iron and silicon elements close to 50 ppm, but contents higher or lower than this value in any of the impurities are also possible.
- This first purification can be obtained for example by a segregation operation identical to that described in the French patent cited above.
- the starting metal may also have been subjected to a treatment to remove peritectic impurities such as titanium and vanadium for example.
- Such a metal is then melted and at least one eutectic element is added to the liquid, in the absence of any crystallization.
- This element is preferably chosen from the group consisting of iron and copper, but the simultaneous addition of these two elements can also be envisaged. What is important is that this element should not have a disturbing concentration after the final operation of segregation. Thus it is possible to add an element having a very high purification coefficient and which can therefore be easily eliminated during the application of the process; one can also add an element having a lower purification coefficient provided that it has no harmful influence, even if its concentration remains high. In the first case, iron can be added whose coefficient is close to 30.
- copper can be used whose coefficient is close to 7 but which, up to contents of 50 ppm, is not not annoying in certain applications and can even be beneficial in the case where aluminum is intended for the manufacture of electrolytic capacitors of medium and high voltage. We can obviously add these two elements simultaneously.
- the quantity added must obviously be such that the concentration of the liquid in this element before crystallization is lower than that of the eutectic, otherwise, as the liquid-solid equilibrium diagrams indicate, the crystals obtained will first be more impure than the initial mother liquid, then there will follow a deposit of crystals of eutectic composition and there will therefore be no possible purification.
- this quantity should also not be too low, otherwise the effect of the addition will not meet the desired objective, namely to avoid mass crystallization which does not allow proper operation to be carried out.
- These additions will depend on the element added and the intended application for the purified metal. For example, in the case of iron, additions of about 100 to 200 ppm, or even 500 ppm, are suitable. However, in the case of copper, they can go beyond 100 ppm and reach 2000 ppm if the aluminum is intended, for example, for the manufacture of capacitors.
- the addition of the eutectic element can be done either in the solid state or in the liquid state and in any suitable form such as pure element, alloy of the elements or master alloy based on aluminum.
- the homogeneity of the liquid after addition is achieved by any suitable stirring or stirring means.
- an aluminum is used containing approximately 20 ppm of silicon and 15 ppm of iron obtained by a first purification operation by segregation. If we add 200 ppm of iron to it and subject it to a new segregation operation, we see that we can bring the silicon to around 5 ppm. As, moreover, the purification coefficient of iron is significantly higher than that of silicon, the fact that iron has been added does not degrade the quality of the final product but, on the contrary, leads to a content close to that silicon and this, with a yield of the order of 70%.
- the present invention finds its application in particular in obtaining aluminum of very high purity in eutectic elements and containing in particular less than 10 ppm of iron and silicon and intended in particular for the manufacture of high and medium voltage capacitors.
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- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Manufacturing & Machinery (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Powder Metallurgy (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Semiconductor Integrated Circuits (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
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Abstract
Description
La présente invention est relative à un procédé d'obtention d'aluminium de très haute pureté en éléments eutectiques par ségrégation.The present invention relates to a process for obtaining very high purity aluminum in eutectic elements by segregation.
L'homme de l'art sait par le DE-A-886 077 et le GB-A-557553 qu'il est possible d'ajouter des éléments eutectiques pour purifier l'aluminium hypereutectique, la phase purifiée étant alors la phase liquide.Those skilled in the art know from DE-A-886 077 and GB-A-557553 that it is possible to add eutectic elements to purify the hypereutectic aluminum, the purified phase then being the liquid phase.
Il sait aussi qu'il est possible de diminuer dans l'aluminium de pureté courante la teneur en éléments dits eutectiques tels que le cuivre, le fer, le magnésium, le silicium, le zinc, lorsque ces derniers sont en concentration hypoeutectique. Il faut, par exemple, pour celà soumettre le métal en fusion contenu dans un récipient à une opération de ségrégation au cours de laquelle on fait apparaître par refroidissement des cristaux plus purs en éléments eutectiques que le liquide au sein duquel ils se sont formés. Ces cristaux se rassemblent par gravité au fond du récipient au fur et à mesure de leur formation et, en les tassant, on obtient un solide purifié plus ou moins compact dont la pureté a tendance à décroître en fonction de la masse cristallisée. On poursuit généralement l'opération jusqu'à ce qu'il ne reste plus qu'une faible fraction de la liqueur-mère. Puis, par différents moyens, par exemple par des opérations de sciage effectuées après refroidissement, on peut séparer la masse purifiée de la liqueur-mère restante ou même séparer la masse purifiée en plusieurs fractions de pureté différente.He also knows that it is possible to reduce the content of so-called eutectic elements in copper of current purity such as copper, iron, magnesium, silicon, zinc, when these are in hypoeutectic concentration. For example, it is necessary to subject the molten metal contained in a container to a segregation operation during which cooler crystals of eutectic elements appear than the liquid in which they are formed. These crystals collect by gravity at the bottom of the container as they are formed and, by compacting them, a more or less compact purified solid is obtained, the purity of which tends to decrease as a function of the crystallized mass. The operation is generally continued until only a small fraction of the mother liquor remains. Then, by various means, for example by sawing operations carried out after cooling, it is possible to separate the purified mass from the remaining mother liquor or even to separate the purified mass into several fractions of different purity.
L'efficacité de la purification se traduit généralement par la valeur du coefficient de purification Co/Cg, où Cs est la concentration d'une impureté donnée dans le produit pur obtenu, et Co est la concentration de la même impureté dans le métal mis en oeuvre, Plus ce coefficient est élevé, meilleure est l'efficacité du traitement.The efficiency of the purification generally results in the value of the purification coefficient C o / Cg, where C s is the concentration of a given impurity in the pure product obtained, and C o is the concentration of the same impurity in the metal used, the higher this coefficient, the better the treatment efficiency.
Des procédés basés sur ce principe ont été décrits dans les brevets des Etats-Unis 3303019 et 4 221 590 et français 1 594 154, et conduisent à des coefficients de purification et à des rendements plus ou moins grands suivants les moyens particuliers mis en oeuvre.Processes based on this principle have been described in United States patents 3303019 and 4,221,590 and French patents 1,594,154, and lead to purification coefficients and to greater or lesser yields depending on the particular means used.
C'est ainsi que, dans le brevet US-3 303 019, on part d'un métal contenant 280 ppm de fer et 420 ppm de silicium et on en récupère 32 % qui ne renferme plus que 30 ppm de silicium et 10 ppm de fer, ce qui correspond à des coefficients de .purification de 14 pour le silicium et 28 pour le fer pour un rendement de 32 %.Thus, in US Pat. No. 3,303,019, we start from a metal containing 280 ppm of iron and 420 ppm of silicon and we recover 32% of it which now contains only 30 ppm of silicon and 10 ppm of iron, which corresponds to the purification coefficients of 14 for silicon and 28 for iron for a yield of 32%.
Dans l'autre brevet US-4 221 590, qui constitue un perfectionnement du précédent, si l'on améliore le rendement en métal purifié ayant une teneur en silicium voisine de 100 ppm, par contre, on ne descend guère en-dessous de 20 ppm du même élément pour la fraction d'aluminium la plus pure et qui ne représente que 30 % environ de la masse mise en oeuvre.In the other patent US Pat. No. 4,221,590, which constitutes an improvement on the previous patent, if the yield of purified metal having a silicon content close to 100 ppm is improved, on the other hand, it hardly drops below 20 ppm of the same element for the purest aluminum fraction and which represents only about 30% of the mass used.
En ce qui concerne le brevet français 1 594 154, on obtient, soit à partir d'un métal contenant 320 ppm de silicium et 270 ppm de fer, des teneurs respectives de 20 et 15 ppm, ce qui correspond à des coefficients de purification de 16 et 18, valeurs déjà très élevées si l'on tient compte du rendement important obtenu puisqu'il est de l'ordre de 70 %, soit à partir d'un métal renfermant 620 ppm de silicium et 550 ppm de fer et avec un rendement de 50 %, un métal ne contenant plus que 40 et 10 ppm des mêmes éléments, ce qui équivaut à des coefficients de purification de 15,5 et 55, cette dernière valeur étant nettement plus élevée que celle exprimée dans le brevet US-3 303 019 surtout si on remarque que le rendement est de 50 % au lieu de 30%.With regard to French patent 1,594,154, we obtain, either from a metal containing 320 ppm of silicon and 270 ppm of iron, respective contents of 20 and 15 ppm, which corresponds to the purification coefficients of 16 and 18, values already very high if we take into account the significant yield obtained since it is of the order of 70%, ie from a metal containing 620 ppm of silicon and 550 ppm of iron and with a yield of 50%, a metal containing no more than 40 and 10 ppm of the same elements, which is equivalent to purification coefficients of 15.5 and 55, the latter value being significantly higher than that expressed in US-3 patent 303 019 especially if we notice that the yield is 50% instead of 30%.
Toutefois, il s'est avéré nécessaire, pour certaines applications particulières, de disposer d'aluminium de pureté encore plus grande que celle obtenue avec les procédés précédents. C'est ainsi par exemple que, pour la confection des condensateurs électrolytiques de moyenne et haute tension, on a de plus en plus recours à des feuilles d'aluminium dont la teneur en Si et Fe doit être seulement de quelques ppm, bien que la présence de certains éléments tels que le cuivre puisse atteindre des concentrations nettement plus élevées sans pour autant être gênante.However, it has proved necessary, for certain particular applications, to have aluminum of even greater purity than that obtained with the preceding processes. Thus, for example, for the manufacture of medium and high voltage electrolytic capacitors, use is increasingly made of aluminum foils whose Si and Fe content must be only a few ppm, although the the presence of certain elements such as copper can reach significantly higher concentrations without being annoying.
Pour atteindre de tels niveaux de pureté, on peut, dans le cas du brevet français, sélectionner les fractions les plus pures, c'est-à-dire celles qui se forment en début d'opération, mais on s'aperçoit que le rendement de récupération est alors très faible et de l'ordre par exemple de 10 % environ de la quantité de métal mis en oeuvre.To achieve such levels of purity, it is possible, in the case of the French patent, to select the purest fractions, that is to say those which form at the start of the operation, but it can be seen that the yield recovery is then very low and of the order of, for example, around 10% of the amount of metal used.
On a alors cherché a appliquer la ségrégation à un métal ayant déjà subi une première purification soit par ségrégation soit par un autre procédé tel que le raffinage par électrolyse en trois couches.We then sought to apply segregation to a metal which has already undergone a first purification either by segregation or by another process such as refining by electrolysis in three layers.
Mais, on s'est heurté àd'importantes difficultés pour conduire l'opération. On observe en effet que, pour des métaux déjà très purs, le liquide a tendance à se solidifier en masses de gros volume sur les parois du dispositif de tassage et même du creuset. Ceci va à l'encontre du but recherché puisqu'il est dit dans le brevet français 1 594154 que, pour obtenir une purification efficace, il faut chercher à avoir une solidification en petits cristaux pour limiter la quantité de liqueur-mère qu'ils retiennent entre eux. Il est très vraisemblable que cette difficulté vient de ce que plus un métal est pur, plus l'intervalle de solidification, c'est-à-dire la différence de température entre le liquidus et le solidus du diagramme d'équilibre est faible.However, we encountered major difficulties in conducting the operation. It is observed in fact that, for already very pure metals, the liquid tends to solidify into masses of large volume on the walls of the tamping device and even of the crucible. This goes against the aim sought since it is said in French patent 1,594,154 that, to obtain an effective purification, it is necessary to seek to have a solidification in small crystals to limit the quantity of mother liquor that they retain between them. It is very likely that this difficulty comes from the fact that the purer a metal, the smaller the solidification interval, that is to say the temperature difference between the liquidus and the solidus of the equilibrium diagram.
C'est pourquoi, la demanderesse a cherché et mis au point les moyens permettant de pallier les difficultés résultant de la mise en oeuvre dans un procédé de ségrégation de métal ayant une pureté relativement élevée et d'améliorer ainsi le taux de purification tout en maintenant un rendement élevé.This is why, the Applicant has sought and developed the means making it possible to overcome the difficulties resulting from the implementation in a process of metal segregation having a relatively high purity and thus to improve the purification rate while maintaining high efficiency.
Ce procédé d'obtention d'aluminium de très haute pureté, c'est-à-dire contenant au plus 10 ppm en chacun des éléments eutectiques fer et silicium consiste à soumettre un aluminium contenant moins de 200 ppm des mêmes éléments à une opération de ségrégation, mais caractérisé en ce que l'on ajoute à l'aluminium fondu, au moins un élément eutectique ayant un coefficient de purification au moins égal à 7 en quantité telle que sa concentration dans le liquide après ajout soit comprise entre un minimum évitant la cristallisation en masse et l'eutectique.This process for obtaining very high purity aluminum, that is to say containing at most 10 ppm in each of the iron and silicon eutectic elements, consists in subjecting an aluminum containing less than 200 ppm of the same elements to an operation of segregation, but characterized in that at least one eutectic element having a purification coefficient at least 7 in quantity is added to the molten aluminum, such that its concentration in the liquid after addition is between a minimum avoiding the mass crystallization and eutectics.
Ainsi, le procédé de l'invention met en oeuvre un aluminium déjà très pur, par exemple qui a déjà subi une première purification qui a permis d'amener sa teneur en impuretés totales à 200, et même jusqu'à 100 ppm ou moins. Cet aluminium peut avoir par exemple une teneur en chacun des éléments fer et silicium voisine de 50 ppm, mais des teneurs supérieures ou inférieures à cette valeur en l'une quelconque des impuretés sont également possibles.Thus, the process of the invention uses an aluminum which is already very pure, for example which has already undergone a first purification which has made it possible to bring its content of total impurities to 200, and even up to 100 ppm or less. This aluminum may for example have a content of each of the iron and silicon elements close to 50 ppm, but contents higher or lower than this value in any of the impurities are also possible.
Cette première purification peut être obtenue par exemple par une opération de ségrégation identique à celle décrite dans le brevet français cité plus haut. Le métal de départ peut aussi avoir subi un traitement pour enlever les impuretés peritectiques telles que le titane et le vanadium par exemple.This first purification can be obtained for example by a segregation operation identical to that described in the French patent cited above. The starting metal may also have been subjected to a treatment to remove peritectic impurities such as titanium and vanadium for example.
Un tel métal est alors fondu et on ajoute au liquide, en l'absence de toute cristallisation, au moins un élément eutectique. Cet élément est préférentiellement choisi dans le groupe constitué par le fer et le cuivre, mais l'addition simultanée de ces deux éléments peut aussi être envisagée. Ce qui importe, c'est que cet élément ne doit pas avoir une concentration génante après l'opération finale de ségrégation. C'est ainsi qu'on peut ajouter un élément ayant un très grand coefficient de purification et qu'il peut dont être facilement éliminé lors de l'application du procédé ; on peut ajouter aussi un élément ayant un coefficient de purification plus faible pour autant qu'il n'ait aucune influence nuisible, même si sa concentration reste élevée. Dans le premier cas, on peut ajouter du fer dont le coefficient est voisin de 30. Dans le deuxième cas, on peut utiliser du cuivre dont le coefficient est voisin de 7 mais qui, jusqu'à des teneurs de 50 ppm, n'est pas gênant dans certaines applications et peut être même bénéfique dans le cas où l'aluminium est destiné à la fabrication de condensateurs électrolytiques de moyenne et haute tension. On peut évidemment ajouter ces deux éléments simultanément.Such a metal is then melted and at least one eutectic element is added to the liquid, in the absence of any crystallization. This element is preferably chosen from the group consisting of iron and copper, but the simultaneous addition of these two elements can also be envisaged. What is important is that this element should not have a disturbing concentration after the final operation of segregation. Thus it is possible to add an element having a very high purification coefficient and which can therefore be easily eliminated during the application of the process; one can also add an element having a lower purification coefficient provided that it has no harmful influence, even if its concentration remains high. In the first case, iron can be added whose coefficient is close to 30. In the second case, copper can be used whose coefficient is close to 7 but which, up to contents of 50 ppm, is not not annoying in certain applications and can even be beneficial in the case where aluminum is intended for the manufacture of electrolytic capacitors of medium and high voltage. We can obviously add these two elements simultaneously.
La quantité ajoutée doit évidemment être telle que la concentration du liquide en cet élément avant cristallisation, soit inférieure à celle de l'eutectique, sinon, comme l'indiquent les diagrammes d'équilibre liquide-solide, les cristaux obtenus seront d'abord plus impurs que le liquide-mère initial, puis il s'en suivra un dépôt de cristaux de composition eutectique et il n'y aura donc aucune purification possible.The quantity added must obviously be such that the concentration of the liquid in this element before crystallization is lower than that of the eutectic, otherwise, as the liquid-solid equilibrium diagrams indicate, the crystals obtained will first be more impure than the initial mother liquid, then there will follow a deposit of crystals of eutectic composition and there will therefore be no possible purification.
Mais cette quantité ne doit pas non plus être trop faible sinon l'effet de l'ajout ne répondra pas à l'objectif recherché, à savoir d'éviter une cristallisation en masse qui ne permet pas une conduite convenable de l'opération. Ces ajouts dépendront de l'élément ajouté et de l'application visée pour le métal purifié. Par exemple, dans le cas du fer, des ajouts d'environ 100 à 200 ppm, voire même 500 ppm, conviennent. Mais, dans le cas du cuivre, ils peuvent aller au-delà de 100 ppm et atteindre 2000 ppm si l'aluminium est destiné, par exemple, à la fabrication de condensateurs.However, this quantity should also not be too low, otherwise the effect of the addition will not meet the desired objective, namely to avoid mass crystallization which does not allow proper operation to be carried out. These additions will depend on the element added and the intended application for the purified metal. For example, in the case of iron, additions of about 100 to 200 ppm, or even 500 ppm, are suitable. However, in the case of copper, they can go beyond 100 ppm and reach 2000 ppm if the aluminum is intended, for example, for the manufacture of capacitors.
Les teneurs indiquées ne le sont qu'à titre d'exemple, car elles dépendent de la manière dont est conduite l'opération de ségrégation, en particulier de sa durée.The contents indicated are only for example, because they depend on the manner in which the segregation operation is carried out, in particular on its duration.
L'ajout de l'élément eutectique peut être fait soit à l'état solide, soit à l'état liquide et sous toute forme convenable telle que élément pur, alliage des éléments ou alliage-mère à base d'aluminium.The addition of the eutectic element can be done either in the solid state or in the liquid state and in any suitable form such as pure element, alloy of the elements or master alloy based on aluminum.
L'homogénéité du liquide après ajout est réalisée par tout moyen de brassage ou d'agitation convenable.The homogeneity of the liquid after addition is achieved by any suitable stirring or stirring means.
Puis, on procède alors à l'opération de ségrégation proprement dite telle qu'elle est décrite dans le brevet français 1 594 154, à savoir :
- on provoque une solidification progressive au sein du volume de métal liquide maintenu au voisinage de son point de fusion dans un récipient chauffé extérieurement en y plongeant un corps refroidi,
- on rassemble au fond du récipient contenant le métal liquide l'ensemble des petits cristaux qui se forment,
- on tasse les petits cristaux ainsi rassemblés, ce qui chasse le liquide intersticiel impur et on provoque le « frittage de ces petits cristaux, ce qui donne des gros cristaux,
- on sépare la fraction purifiée à gros cristaux de la fraction qui s'est enrichie en impuretés.
- a progressive solidification is caused within the volume of liquid metal maintained near its melting point in an externally heated container by immersing a cooled body in it,
- we collect at the bottom of the container containing the liquid metal all the small crystals that form,
- the small crystals thus collected are packed, which drives out the impure interstitial liquid and the sintering of these small crystals is caused, which gives large crystals,
- the purified fraction with large crystals is separated from the fraction which is enriched in impurities.
On aboutit ainsi a un métal soit extrêmement pur, soit dont la concentration en impuretés eutectiques gênantes est beaucoup plus faible que dans le métal de départ.This results in a metal which is either extremely pure or whose concentration of annoying eutectic impurities is much lower than in the starting metal.
Il est évident que ce procédé peut être mis en oeuvre sans que l'on sorte du cadre de l'invention dans le cas où on utilise des procédés de ségrégation différents de celui décrit ci-dessus.It is obvious that this method can be implemented without departing from the scope of the invention in the case where segregation methods different from that described above are used.
A titre d'exemple de réalisation, on met en oeuvre un aluminium contenant environ 20 ppm de silicium et 15 ppm de fer obtenu par une première opération de purification par ségrégation. Si on lui ajoute 200 ppm de fer et le soumet à une nouvelle opération de ségrégation, on constate qu'on peut amener le silicium aux environs de 5 ppm. Comme, par ailleurs, le coefficient de purification du fer est nettement plus élevé que celui du silicium, le fait que l'on ait rajouté du fer ne dégrade pas la qualité du produit final mais, au contraire, conduit à une teneur voisine de celle du silicium et ce, avec un rendement de l'ordre de 70 %.As an exemplary embodiment, an aluminum is used containing approximately 20 ppm of silicon and 15 ppm of iron obtained by a first purification operation by segregation. If we add 200 ppm of iron to it and subject it to a new segregation operation, we see that we can bring the silicon to around 5 ppm. As, moreover, the purification coefficient of iron is significantly higher than that of silicon, the fact that iron has been added does not degrade the quality of the final product but, on the contrary, leads to a content close to that silicon and this, with a yield of the order of 70%.
Dans un autre exemple d'application, on met en oeuvre 1 000 kg d'aluminium contenant 50 ppm de fer et on lui ajoute 500 ppm de cuivre. On le soumet à une opération de ségrégation pendant 14 heures au bout desquelles on recueille 70 % de la masse mise en oeuvre sous forme d'un solide contenant près de 60 ppm de cuivre, mais moins de 2 ppm de fer. Un tel métal est très intéressant pour la confection de feuilles destinées à la fabrication de condensateurs électrolytiques de haute et moyenne tension, car le cuivre est un élément qui favorise généralement l'obtention de capacités spécifiques élevées.In another application example, 1,000 kg of aluminum containing 50 ppm of iron are used and 500 ppm of copper are added to it. We subjected to a segregation operation for 14 hours at the end of which 70% of the mass used is collected in the form of a solid containing nearly 60 ppm of copper, but less than 2 ppm of iron. Such a metal is very advantageous for making sheets intended for the manufacture of high and medium voltage electrolytic capacitors, since copper is an element which generally promotes the obtaining of high specific capacities.
La présente invention trouve son application notamment dans l'obtention d'aluminium de très haute pureté en éléments eutectiques et contenant notamment moins de 10 ppm de fer et de silicium et destiné en particulier à la fabrication de condensateurs de haute et moyenne tension.The present invention finds its application in particular in obtaining aluminum of very high purity in eutectic elements and containing in particular less than 10 ppm of iron and silicon and intended in particular for the manufacture of high and medium voltage capacitors.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT83420054T ATE21529T1 (en) | 1982-03-31 | 1983-03-24 | PROCESS FOR OBTAINING HIGH PURITY ALUMINUM IN EUTECTIC ELEMENTS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8205895A FR2524490B1 (en) | 1982-03-31 | 1982-03-31 | PROCESS FOR OBTAINING VERY HIGH PURITY ALUMINUM IN EUTECTIC ELEMENTS |
| FR8205895 | 1982-03-31 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0090750A1 EP0090750A1 (en) | 1983-10-05 |
| EP0090750B1 true EP0090750B1 (en) | 1986-08-20 |
Family
ID=9272765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP83420054A Expired EP0090750B1 (en) | 1982-03-31 | 1983-03-24 | Process for obtaining very high purity aluminium in entectic elements |
Country Status (17)
| Country | Link |
|---|---|
| US (1) | US4444585A (en) |
| EP (1) | EP0090750B1 (en) |
| JP (1) | JPS58181835A (en) |
| KR (1) | KR860001306B1 (en) |
| AT (1) | ATE21529T1 (en) |
| AU (1) | AU551209B2 (en) |
| BR (1) | BR8301579A (en) |
| CA (1) | CA1185436A (en) |
| DE (1) | DE3365393D1 (en) |
| ES (1) | ES521015A0 (en) |
| FR (1) | FR2524490B1 (en) |
| GR (1) | GR77984B (en) |
| IN (1) | IN158047B (en) |
| IS (1) | IS1353B6 (en) |
| NO (1) | NO160793C (en) |
| NZ (1) | NZ203683A (en) |
| ZA (1) | ZA832267B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8710200D0 (en) * | 1987-04-29 | 1987-06-03 | Alcan Int Ltd | Light metal alloy treatment |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE886077C (en) * | 1940-07-05 | 1953-08-10 | Vaw Ver Aluminium Werke Ag | Process for the separation of iron from iron-containing aluminum alloys |
| US2464610A (en) * | 1940-07-08 | 1949-03-15 | Spolek | Method for producing aluminumsilicon alloys |
| GB557553A (en) * | 1941-01-01 | 1943-11-26 | British Non Ferrous Metals Res | Improved method of and apparatus for refining metals and alloys |
| FR895518A (en) * | 1942-05-16 | 1945-01-26 | Degussa | Process for the purification of raw lead by filtration |
| DE816016C (en) * | 1948-10-02 | 1951-10-08 | Schmidt Gmbh Karl | Process for separating aluminum or its alloys from impurities by means of metallic solvents |
| FR976205A (en) * | 1948-10-02 | 1951-03-15 | Alais & Froges & Camarque Cie | Process for removing metallic impurities in metals or alloys, in particular in aluminum alloys |
| FR979569A (en) * | 1948-12-03 | 1951-04-27 | Alais & Froges & Camarque Cie | A method of removing unwanted alloying elements or metallic impurities in metals or alloys, particularly in aluminum alloys |
| US3211547A (en) * | 1961-02-10 | 1965-10-12 | Aluminum Co Of America | Treatment of molten aluminum |
| US3303019A (en) * | 1964-04-23 | 1967-02-07 | Aluminum Co Of America | Purification of aluminum |
| FR1594154A (en) * | 1968-12-06 | 1970-06-01 | ||
| DE2401654C2 (en) * | 1974-01-15 | 1975-11-20 | Matthias 4150 Krefeld Welsch | Method and device for the production of aluminum |
| GB1519999A (en) * | 1974-09-30 | 1978-08-02 | Commw Scient Ind Res Org | Method for the continuous reflux reflux refining of metal |
| JPS5912731B2 (en) * | 1978-10-05 | 1984-03-26 | 株式会社神戸製鋼所 | Method for refining aluminum or aluminum alloy |
| US4221590A (en) * | 1978-12-26 | 1980-09-09 | Aluminum Company Of America | Fractional crystallization process |
| NO158107C (en) * | 1979-10-09 | 1988-07-13 | Showa Aluminium Co Ltd | PROCEDURE FOR MELTING ALUMINUM. |
-
1982
- 1982-03-31 FR FR8205895A patent/FR2524490B1/en not_active Expired
-
1983
- 1983-03-23 GR GR70880A patent/GR77984B/el unknown
- 1983-03-23 CA CA000424280A patent/CA1185436A/en not_active Expired
- 1983-03-24 AT AT83420054T patent/ATE21529T1/en not_active IP Right Cessation
- 1983-03-24 IN IN355/CAL/83A patent/IN158047B/en unknown
- 1983-03-24 EP EP83420054A patent/EP0090750B1/en not_active Expired
- 1983-03-24 DE DE8383420054T patent/DE3365393D1/en not_active Expired
- 1983-03-24 NZ NZ203683A patent/NZ203683A/en unknown
- 1983-03-24 IS IS2793A patent/IS1353B6/en unknown
- 1983-03-25 ES ES521015A patent/ES521015A0/en active Granted
- 1983-03-25 US US06/478,785 patent/US4444585A/en not_active Expired - Lifetime
- 1983-03-28 BR BR8301579A patent/BR8301579A/en not_active IP Right Cessation
- 1983-03-29 JP JP58053461A patent/JPS58181835A/en active Granted
- 1983-03-30 AU AU12998/83A patent/AU551209B2/en not_active Ceased
- 1983-03-30 ZA ZA832267A patent/ZA832267B/en unknown
- 1983-03-30 NO NO831192A patent/NO160793C/en unknown
- 1983-03-31 KR KR1019830001326A patent/KR860001306B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NZ203683A (en) | 1986-06-11 |
| CA1185436A (en) | 1985-04-16 |
| JPH022937B2 (en) | 1990-01-19 |
| FR2524490A1 (en) | 1983-10-07 |
| IN158047B (en) | 1986-08-23 |
| ATE21529T1 (en) | 1986-09-15 |
| NO160793C (en) | 1989-05-31 |
| DE3365393D1 (en) | 1986-09-25 |
| JPS58181835A (en) | 1983-10-24 |
| BR8301579A (en) | 1983-12-06 |
| GR77984B (en) | 1984-09-25 |
| NO160793B (en) | 1989-02-20 |
| IS2793A7 (en) | 1983-10-02 |
| EP0090750A1 (en) | 1983-10-05 |
| FR2524490B1 (en) | 1988-05-13 |
| ES8405446A1 (en) | 1984-06-01 |
| AU1299883A (en) | 1983-10-06 |
| NO831192L (en) | 1983-10-03 |
| ZA832267B (en) | 1983-12-28 |
| IS1353B6 (en) | 1989-04-19 |
| AU551209B2 (en) | 1986-04-17 |
| KR840004178A (en) | 1984-10-10 |
| KR860001306B1 (en) | 1986-09-11 |
| US4444585A (en) | 1984-04-24 |
| ES521015A0 (en) | 1984-06-01 |
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