ELECTROCHEMICAL PRODUCTION OF RARE EARTH ALLOYS AND METALS COMPRISING A LIQUID ANODE

Description

[0001] The work leading to this invention has received funding from the European Union's Horizon 2020 and Innovation program under Grant Agreement No. 680507.

FIELD OF THE INVENTION

[0002] The present invention is related to electrochemical production of rare earth alloys and metals, and especially to a one-step electrochemical production method comprising a liquid anode.

BACKGROUND OF THE INVENTION

[0003] Rare earth alloys and metals are important ingredients in modern electronic components like semiconductors, but also in products like permanent magnets etc. The Peoples Republic of China is dominating the production of rare earth (RE), and for example, in 2011 the Chinese production covered 97 % of the world market. In addition, the geological availability and distribution of RE is unevenly distributed around the world and it is therefore an international interest in developing alternative second sources of RE materials mitigating any problems related to higher prices and reliable and sustainable delivery of RE alloys and metals.

[0004] This situation has triggered development of methods and systems recovering RE alloys and metals from scrap metals and permanent magnets. A general overview of prior art techniques providing recycling of permanent magnets can be found in the article "Technique for recovering rare-earth metals from spent sintered Nd-Fe-B magnets without external heating" by R. Sasai and N. Shimamura, Journal of Asian Ceramic Societies, 4 (2016) 155-158.

[0005] Prior art electrochemical refining of metals is applied both in aqueous and molten salt electrochemical processes. The refining is commonly based on an impure metal containing anode being refined to a pure cathode. More noble impurities remain in the anode or anode compartment and less noble substances accumulate in the electrolyte.

[0006] An example of prior art is the three-layer refining of liquid aluminium dissolved in a copper containing alloy invented by Hoopes and patented in 1925. The refining process takes place in a vertically arranged molten salt cell, wherein the aluminium dissolved in the copper alloy is arranged at the bottom of the cell, and the refined pure aluminium is floating at the top of the electrolyte. The prior art documents CN 104 789 991 A and US2961387 A relates to electrolysis processes using the Hoopes principles.

[0007] A common technique in prior art when recycling used permanent magnets and scrap metals comprises a step of oxidizing the permanent magnet and scrap metal materials followed by a purifying step and electrolysis of oxidized materials dissolved in a molten salt.

[0008] An example of prior art is CN 103409649B disclosing a liquid metal and molten salt reduction method and apparatus for extraction and separation of rare earth metals comprising a liquid aluminium cathode and an anode graphite rod added to a heated bath melted as an electrolyte. Lithium aluminium-lithium alloy is dissolved in the liquid aluminium.

[0009] Another example of prior art is J. Lucas, P. Lucas, T. Le Mercier, A. Rollat and W. Davenport, in "Rare Earths. Science, Technology, Production and Use", Elsevier 2015.

[0010] A further prior art reference is S. Pang, S. Yan, Z. Li, D. Chen, L. Xu and B. Zhao, "Development on Molten Salt Electrolytic Methods and Technology for Preparing Rare Earth Metals and Alloys in China", Chinese Journal of Rare Metals, 35(3) (2011) 440-450.

[0011] Recovering RE alloys and metals from a specific electrochemical process is also subject to cost/benefit assessments in addition to environmental considerations. The cost of recovered RE alloys and metals has to be on a level accepted by end users of the recovered materials. Therefore, there is a need of improved methods recovering compounds comprising rare earth, and/or rear earth alloys and/or rear earth metals.

[0012] An aspect of the present invention is to reduce the number of process steps, and at the same time increase output of rare earth alloys and metals from the process.

[0013] The present invention is based on an alloy system with high solubility of the actual rare earth metal(s) or rare earth alloy(s).

OBJECT OF THE INVENTION

[0014] In particular, it may be seen as an object of the present invention to provide a method of recycling rear earth (RE) containing permanent magnets and/or scrap metals by providing a liquid anode with dissolved material to be recycled in an electrochemical process in one step.

[0015] It is a further object of the present invention to provide an alternative to the prior art.

SUMMARY OF THE INVENTION

[0016] Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a method of recycling elements including compounds comprising RE alloys and/or RE metals from raw materials including permanent magnets and/or scrap metals containing iron (Fe) and elements to be recycled in an electrochemical process from a molten salt, comprising steps of:

• arranging an electrolysis cell comprising a liquid anode residing in an anode compartment in communication with an electric lead of the liquid anode, a cathode and a compartment below the cathode collecting refined recycled elements in a liquid or solid state separated by a fluoride based liquid electrolyte,
• feeding the raw materials into the liquid anode compartment,
• the liquid anode is forming a multinary liquid alloy system when raw materials fed to the anode compartment are dissolved,
• the liquid anode comprises added Al and Si in quantities providing a melting point temperature of the added materials inside the anode compartment being below the melting point temperature of the raw materials itself,
• the added quantities of Al and Si is further selected to provide a low melting temperature region of Al-Si alloys being able to dissolve Fe, and a maximum or sufficient wt% amount to maintain molten Fe-Al-Si-RE alloys of different compositions,
• collecting refined recycled RE metals(s) or RE alloy(s) in the compartment below the cathode at the bottom of the electrolysis cell.

[0017] A second aspect of the invention relates to an electrochemical production cell as stated in the independent claim 10

DESCRIPTION OF THE FIGURES

[0018] The method and system thereof according to the present invention will now be described in more detail with reference to the accompanying figures. The accompanying figures illustrate an example of embodiment of the present invention and are not to be construed as being limiting other possible embodiments falling within the scope of the attached claim set.

Figure 1 illustrates some respective aspects of the present invention.

Figure 2 illustrates further aspects of the present invention.

Figure 3 illustrates an example of embodiment of the present invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0019] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. The mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous The known technology used in China relies on an electrolytic process using a vertically arranged cell comprising consumable carbon anodes and molybdenum or tungsten as inert or iron as consumable cathode materials. The RE or RE alloy is deposited in a liquid form at a temperature around 1050 °C. The electrolyte consists of an equimolar REF₃-LiF mixture, and the RE₂O₃ raw material is applied batch wise or continuously at the top of the electrolyte.

[0020] A parameter of interest when designing an electrolysis cell is the kinetics of the electrodes. It is believed that liquid anodes perform better in this respect than an anode consisting of solid chunks of alloys when refining rare earth elements.

[0021] An example of a prior art liquid anode is the referenced Hoppes method. However, applying Hoppes three layer method when electro-refining rare earth element from for example used permanent magnets would be a challenge due to the high specific densities of the rare earth elements and the lack of electrolytes with an intermediate density between the refined element(s) and the composition containing the raw material.

[0022] However, a different cell design according to the present invention with a liquid anode is schematically illustrated in Figure 1. The rare earth containing raw material is placed in the anode compartment 10 from where the RE present in the raw material (for example Nd, Dy, Pr) will be anodically dissolved in the form of ions, which will be discharged at the cathode 11 as metals and/or magnetic rare earth alloys 12. The recovery of REs from the raw material can be extracted, and a valuable product (RE or alloy) can be obtained in one single electrochemical step.

[0023] It is not desirable to work at a high temperature providing a liquid state of the used permanent magnets for example. The melting point of most permanent magnets is about 1400 °C. The high temperature is a challenge since the temperature may enhance corrosion of the cell materials. Therefore, according to an aspect of the present invention, a desired working temperature is below 1100 °C.

[0024] Providing a lower melting point when recycling permanent magnets and/or scrap metal comprising Fe, can be achieved by adding low melting point materials known to achieve such an effect. For example, with respect to a permanent magnet comprising Nd, it is known that Cu forms low melting phases with Nd, but not with Fe. However, using Al the inventors has demonstrated that Al forms low melting areas with Nd and Fe in the Al rich regions. Calculating a ternary phase diagram of Al-Nd-Fe can be achieved with commercially available thermodynamic computer programs like FactSage as known in prior art. The same demonstration has been performed with other RE elements with similar results.

[0025] However, there are further aspects to be taken into consideration when arranging a liquid anode forming a multinary liquid alloy system that fulfils all requirements necessary for an electrochemical process providing necessary efficiency and output of recovered RE elements, alloys and metals from raw materials comprising at least Fe and RE.

[0026] Examples of further requirements are:

• Forming a homogenous liquid phase with raw materials comprising at least Fe and RE.
• Providing a melting point of an anode alloy comprising at least Fe and Re to be around 1050 °C or lower.
• Low vapour pressure at the working temperature, for example at 1050 °C.
• Low cost, non-toxic and abundant materials.

[0027] It is further known that Si forms low melting point alloys with several elements like Cu and Al. When calculating and verifying the calculations in a laboratory test of a phase diagram of Fe-Al-Si, it is possible to observe that the phase diagram reveals a relative large region of molten Fe-Al-Si alloys of different compositions that exist below a temperature of 1050 °C. Further, it is also evident from such calculations and laboratory verifications that the liquid content of Fe at 1050 °C varies from 20 wt% without Si present to a maximum of 50 wt% when Si is present. Further, Al-Si alloys are commercially available, which is an important aspect when considering commercial applications of a liquid anode according to the present invention comprising AlSi.

[0028] According to an aspect of the present invention, AlSi is added to the liquid anode.

[0029] Figure 2 illustrates examples of how liquidus curves of the quaternary system of AlSi-Fe-Nd can be obtained. The same type of illustrations is valid for other RE elements. The cross sections of the AlSi-Fe-RE system from contact lines between the AISi corner and the Fe-RE (for example Nd) side of the triangle in figure 2 will provide liquidus curves enabling a prediction of melting points of the anode alloy when the electrolysis proceeds and the content of respectively RE and Fe decreases and increases.

[0030] Higher concentration of Si will for example increase the amount of Fe-RE in the liquid phase at 1050 °C when there is a rich Fe composition. If the concentration of RE is high the opposite is observed. However, laboratory verification of this aspect of the present invention confirms a liquid phase with more than 30 wt% of permanent magnet material and scrap metal comprising Fe and RE at 1050 °C.

[0031] Below is a table illustrating non-limiting examples of different anode-alloy compositions when recycling a permanent magnet comprising Fe and RE.

Table 1:

Alloy#	Al:Si composition wt%:wt%	Composition Al:Si: Magnet wt%:wt% wt%	Remarks
1	70:30	54:23:23	Homogeneous
2	70:30	48:21:31	Homogeneous
3	70:30	44:19:37	Homogeneous
4	90:10	54:6:40	Homogeneous

[0032] According to an example of embodiment of the present invention, a liquid anode is formed of aluminium and silicon and dissolved RE alloys with iron and boron (Al-Si-Fe-RE-B).

[0033] Therefore, the addition of Al and Si lowers the melting point. Further, the liquid anode is forming a multinary liquid alloy system having a larger liquid domain for the RE, RE alloys or RE metals dissolved in the liquid anode. Further, the multinary liquid alloy system is provided with metal elements being more noble than the RE or the RE containing alloy(s) to be recycled.

[0034] According to the present invention, a method of recycling RE alloys and/or RE metals from raw materials including permanent magnets and/or scrap metals containing RE and iron (Fe) in an electrochemical process from a molten salt, comprises the steps of:

• arranging an electrolysis cell comprising a liquid anode residing in an anode compartment in communication with an electric lead of the liquid anode, a cathode and a compartment below the cathode collecting refined recycled elements in a liquid or solid state separated by a fluoride based liquid electrolyte,
• feeding raw material into the liquid anode compartment,
• the liquid anode is forming a multinary liquid alloy system when dissolving raw materials fed to the anode compartment,
• the liquid anode comprises added Al and Si in quantities providing a melting point temperature of the added materials inside the anode compartment being below the melting point temperature of the raw materials itself,
• the added quantities of Al and Si is further selected to provide a low melting temperature region of Al-Si alloys being able to dissolve Fe, and a maximum or sufficient wt% amount to maintain molten Fe-Al-Si-RE alloys of different compositions,
• collecting refined recycled RE metal(s) or RE alloy(s) in the compartment below the cathode at the bottom of the electrolysis cell.

[0035] Further, the added specific amounts of respectively Al and Si elements are forming a multinary liquid alloy system having a working temperature below the melting point of the rare earth containing metallic raw material, preferable in the range of 1000-1100 °C.

[0036] Further, the working temperature of the liquid anode may be 1050 °C.

[0037] Further, the cathode may be a Fe cathode and the reactions are as follows:

anode:	RE-alloy (liquid) -> RE(III) + alloy anode (liquid) + 3e-
cathode:	RE(III) + Fe(solid) + 3e- -> RE-Fe (liquid).

[0038] Further, the step of dissolving permanent magnetic material may provide a liquid anode comprising Al-Si-Fe-RE-B.

[0039] Further, the permanent magnets may be Nd based permanent magnets.

[0040] Further, the cathode may be a solid cathode and the step of collecting recycled elements comprises collecting the RE(s) or RE alloy(s) in solid form.

[0041] Further, the step of collecting the RE(s) or RE alloy(s) may comprise collecting liquid iron-RE(s) alloys formed through a reaction on a consumable iron cathode.

[0042] Further, the RE containing permanent magnets and/or scrap metals may be delivered into the liquid anode compartment from a feeding chamber.

[0043] Figure 3 illustrates an example of principles of a functional cell according to the present invention. A tube or canal 20 provides transport of waste material to be recycled into the molten alloy being part of the liquid anode 21 residing in a compartment. An electric lead 22 is connected to a positive electric pole 23 of the power supply. The electric lead 22 is connected to a finger like electrode configuration being arranged inside the molten alloy. The cathode 24 is connected to the negative pole of the power supply and at the bottom of the cell below the cathode a compartment is arranged receiving cathode products.

Claims

1. A method of recycling RE alloys and/or RE metals from raw materials including permanent magnets and/or scrap metals containing RE and iron (Fe) in, an electrochemical process from a molten salt comprising the steps of:

- arranging an electrolysis cell comprising a liquid anode (21) residing in an anode compartment in communication with an electric lead (22) of the liquid anode, a cathode (24) and a compartment arranged below the cathode at the bottom of the cell collecting refined recycled elements in a liquid or solid state, separated by a fluoride based liquid electrolyte,

- feeding the raw materials into the liquid anode compartment,

- the liquid anode is forming a multinary liquid alloy system when the raw materials fed to the anode compartment are dissolved,

- the liquid anode comprises added Al and Si in quantities providing a melting point temperature of the added materials inside the anode compartment being below the melting point temperature of the raw materials itself,

- the added quantities of Al and Si is further selected to provide a low melting temperature region of Al-Si alloys being able to dissolve Fe, and a maximum or sufficient wt% amount to maintain molten Fe-Al-Si-RE alloys of different compositions,

- collecting refined recycled RE metals(s) or RE alloy(s) in the compartment below the cathode at the bottom of the electrolysis cell.

2. The method according to claim 1, wherein added specific amounts of respectively Al and Si elements are forming a multinary liquid alloy system having a working temperature below the melting point of the RE metal(s) or the RE containing alloy(s), preferably in the range of 1000-1100 °C.

3. The method according to claim 2, wherein the working temperature of the liquid anode is 1050 °C.

4. The method according to claim 1, wherein the cathode is a Fe cathode and the reactions are as follows:

anode:	RE-alloy (liquid) -> RE(III) + alloy anode (liquid) + 3e-
cathode:	RE(III) + Fe(solid) + 3e- -> RE-Fe (liquid).

5. The method according to any claim 1-4, wherein the step of dissolving the raw material provides a liquid anode comprising Al-Si-Fe-RE-B.

6. The method according to any claim 1-5, wherein the raw material is Nd based permanent magnets.

7. The method according to claim 1, wherein the cathode is a solid cathode and the step of collecting refined recycled elements comprises collecting the RE metal(s) or RE alloy(s) in solid form.

8. The method according to claim 1, wherein the step of collecting the RE metal(s) or RE alloy(s) comprises collecting liquid iron-RE alloy(s) formed through a reaction on a consumable iron cathode.

9. The method according to claim 1, wherein the raw materials are delivered into the liquid anode compartment from a feeding chamber.

10. An electrochemical production cell arranged to 2. perform a method according to any of claims 1-9, comprising

- a liquid anode (21) that comprises added quantities of Al and Si as defined in claim 1 and that resides in an anode compartment, the liquid anode (21) is connected to a positive electric pole (23) via an electric lead (22), and

- a cathode (24) connected to a negative pole, the cathode is separated from the liquid anode by a fluoride based liquid electrolyte, and

- a compartment for collecting refined recycled RE metals(s) or RE alloy(s) is arranged below the cathode (24) at the bottom of the electrochemical cell,

and wherein the cell comprises a tube or channel (20) for transport of waste materials into the liquid anode (21).

Ansprüche

1. Verfahren zum Recyceln von RE(rare earth - seltene Erden)-Legierungen und/oder RE-Metallen aus Rohmaterialien, einschließlich Permanentmagneten und/oder Altmetallen, die RE und Eisen (Fe) in einem elektrochemischen Vorgang von einer Salzschmelze enthalten, der folgende Schritte umfasst:

- Anordnen einer Elektrolysezelle, die eine Flüssiganode (21) aufweist, die sich in einem Anodenfach befindet, das in Verbindung mit einer elektrischen Leitung (22) der Flüssiganode steht, einer Kathode (24) und eines Fachs, das unterhalb der Kathode an dem Boden der Zelle angeordnet ist, das veredelte recycelte Elemente in flüssigem oder festem Zustand sammelt, die durch einen Flüssigelektrolyten auf Fluoridbasis getrennt sind,

- Zuführen der Rohmaterialien in das Flüssiganodenfach,

- wobei die Flüssiganode ein multinäres Flüssiglegierungssystem ausbildet, wenn die Rohmaterialien, die dem Anodenfach zugeführt werden, gelöst werden,

- wobei die Flüssiganode zugesetztes AI und Si in Mengen umfasst, die eine Schmelzpunkttemperatur der zugesetzten Materialien innerhalb des Anodenfachs bereitstellen, die unter der Schmelzpunkttemperatur der Rohmaterialien selbst liegt,

- wobei die zugesetzten Mengen von AI und Si ferner ausgewählt werden, um eine Region niedriger Schmelztemperatur von Al-Si-Legierungen, die Fe lösen können, und eine maximale oder ausreichende Gew.-%-Menge, um geschmolzene Fe-Al-Si-RE-Legierungen unterschiedlicher Zusammensetzungen aufrechtzuerhalten, bereitzustellen,

- Sammeln von veredeltem/veredelten recyceltem/recycelten RE-Metall(en) oder RE-Legierung(en) in dem Fach unterhalb der Kathode an dem Boden der Elektrolysezelle.

2. Verfahren nach Anspruch 1, wobei zugesetzte spezifische Mengen von Albeziehungsweise Si-Elementen ein multinäres Flüssiglegierungssystem ausbilden, das eine Arbeitstemperatur unter dem Schmelzpunkt des/der RE-Metalls/-Metalle oder der RE-haltigen Legierung(en) aufweist, vorzugsweise in dem Bereich von 1.000-1.100 °C.

3. Verfahren nach Anspruch 2, wobei die Arbeitstemperatur der Flüssiganode 1.050 °C beträgt.

4. Verfahren nach Anspruch 1, wobei die Kathode eine Fe-Kathode ist und die Reaktionen wie folgt sind:

Anode:	RE-Legierung (flüssig) -> RE(III) + Legierungsanode (flüssig) + 3e-
Kathode:	RE(III) + Fe(fest) + 3e--> RE-Fe (flüssig).

5. Verfahren nach einem der Ansprüche 1-4, wobei der Schritt des Lösens des Rohmaterials eine Flüssiganode bereitstellt, die Al-Si-Fe-RE-B umfasst.

6. Verfahren nach einem der Ansprüche 1-5, wobei das Rohmaterial aus Permanentmagneten auf Nd-Basis besteht.

7. Verfahren nach Anspruch 1, wobei die Kathode eine feste Kathode ist und der Schritt des Sammelns von veredelten recycelten Elementen ein Sammeln des/der RE-Metalls/- Metalle oder der RE-Legierung(en) in fester Form umfasst.

8. Verfahren nach Anspruch 1, wobei der Schritt des Sammelns des/der RE-Metalls/-Metalle oder der RE-Legierung(en) das Sammeln (einer) flüssigen/flüssiger Eisen-RE-Legierung(en) umfasst, die durch eine Reaktion auf einer abschmelzbaren Eisenkathode ausgebildet wird/werden.

9. Verfahren nach Anspruch 1, wobei die Rohmaterialien aus einer Zufuhrkammer in das Flüssiganodenfach abgegeben werden.

10. Elektrochemische Produktionszelle, die angeordnet ist, um ein Verfahren nach einem der Ansprüche 1-9 durchzuführen, die Folgendes umfasst:

- eine Flüssiganode (21), die zugesetzte Mengen an Al und Si nach Anspruch 1 umfasst und die sich in einem Anodenfach befindet, wobei die Flüssiganode (21) über eine elektrische Leitung (22) mit einem positiven elektrischen Pol (23) verbunden ist, und

- eine Kathode (24), die mit einem negativen Pol verbunden ist, wobei die Kathode durch einen Flüssigelektrolyten auf Fluoridbasis von der Flüssiganode getrennt ist, und

- ein Fach zum Sammeln von veredeltem/veredelten recyceltem/recycelten RE-Metall(en) oder RE-Legierung(en), das unterhalb der Kathode (24) an dem Boden der elektrochemischen Zelle angeordnet ist, und wobei die Zelle ein Rohr oder einen Kanal (20) für einen Transport von Abfallmaterialien in die Flüssiganode (21) umfasst.

Revendications

1. Procédé de recyclage d'alliages terres rares (TR) et/ou de métaux TR à partir de matières premières comportant des aimants permanents et/ou des ferrailles contenant des TR et du fer (Fe), dans un processus électrochimique à partir d'un sel fondu comprenant les étapes suivantes :

- l'agencement d'une cellule d'électrolyse comprenant une anode liquide (21) résidant dans un compartiment d'anode en communication avec un conducteur électrique (22) de l'anode liquide, une cathode (24) et un compartiment agencé sous la cathode au fond de la cellule collectant des éléments recyclés raffinés à l'état liquide ou solide, séparés par un électrolyte liquide à base de fluorure,

- l'alimentation des matières premières dans le compartiment d'anode liquide,

- l'anode liquide forme un système d'alliage liquide multinaire lorsque les matières premières alimentées dans le compartiment d'anode sont dissoutes,

- l'anode liquide comprend de l'Al et du Si ajoutés en quantités fournissant une température de point de fusion des matières ajoutées à l'intérieur du compartiment d'anode inférieure à la température de point de fusion des matières premières elles-mêmes,

- les quantités ajoutées d'AI et de Si sont en outre sélectionnées pour fournir une région à basse température de fusion d'alliages d'Al-Si pouvant dissoudre le Fe, et une quantité en % en poids maximale ou suffisante pour maintenir les alliages Fe-Al-Si-TR fondus de différentes compositions,

- la collecte du métal / des métaux TR ou du / des alliage(s) TR recyclé(s) raffiné(s) dans le compartiment sous la cathode au fond de la cellule d'électrolyse.

2. Procédé selon la revendication 1, dans lequel des quantités spécifiques ajoutées d'éléments respectivement Al et Si forment un système d'alliage liquide multinaire ayant une température de travail inférieure au point de fusion du métal / des métaux TR ou du / des alliage(s) contenant des TR, de préférence dans la plage comprise entre 1 000 et 1 100 °C.

3. Procédé selon la revendication 2, dans lequel la température de travail de l'anode liquide est de 1 050 °C.

4. Procédé selon la revendication 1, dans lequel la cathode est une cathode en Fe et les réactions sont les suivantes :

anode :	alliage TR (liquide) -> TR(III) + anode en alliage (liquide) + 3e-
cathode :	TR(III) + Fe (solide) + 3e- -> TR-Fe (liquide).

5. Procédé selon l'une quelconque des revendications 1 à 4, dans lequel l'étape de dissolution de la matière première fournit une anode liquide comprenant AI-Si-Fe-TR-B.

6. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la matière première est des aimants permanents à base de Nd.

7. Procédé selon la revendication 1, dans lequel la cathode est une cathode solide et l'étape de collecte d'éléments recyclés raffinés comprend la collecte du métal / des métaux TR ou du / des alliage(s) TR sous forme solide.

8. Procédé selon la revendication 1, dans lequel l'étape de collecte du métal / des métaux TR ou du / des alliage(s) TR comprend la collecte du / des alliage(s) fer-TR liquide(s) formé(s) par réaction sur une cathode en fer consommable.

9. Procédé selon la revendication 1, dans lequel les matières premières sont délivrées dans le compartiment d'anode liquide à partir d'une chambre d'alimentation.

10. Cellule de production électrochimique agencée pour exécuter un procédé selon l'une quelconque des revendications 1 à 9, comprenant :

- une anode liquide (21) qui comprend des quantités ajoutées d'AI et de Si telle que définie selon la revendication 1 et qui réside dans un compartiment d'anode, l'anode liquide (21) étant connectée à un pôle électrique positif (23) par l'intermédiaire d'un conducteur électrique (22), et

- une cathode (24) connectée à un pôle négatif, la cathode étant séparée de l'anode liquide par un électrolyte liquide à base de fluorure, et

- un compartiment de collecte du métal / des métaux TR ou du / des alliage(s) TR recyclé(s) raffiné(s) est disposé sous la cathode (24) au fond de la cellule électrochimique et dans laquelle la cellule comprend un tube ou un canal (20) pour le transport des déchets dans l'anode liquide (21).

Drawing