Method for processing and / or recycling black mass, black mass, and the use thereof

Abstract

The invention relates to a method for processing and / or recycling black mass, comprising the following steps: a) providing a metal-free black mass; b) treating the metal-free black mass with a metal salt in order to obtain a black mass having a predetermined metal- and / or metal-oxide content; and / or c) adding a promotor element which is selected from the group consisting of N, P, S and / or B, to the metal-free black mass or to the black mass having the predetermined metal- and / or metal-oxide content. The invention also relates to a black mass which is obtained according to the method, and to its use as an electrode material, electrochemical catalyst, or as a heterogeneous catalyst.

Description

[0001]adares SUE-104-WO Graphite Recycling - 1 - Process for the refining and / or recycling of black mass, black mass and its use The invention relates to a process for the refining and / or recycling of black mass, a black mass and its use. Black mass arises in particular in the recycling of old batteries from electric vehicles and, due to increasing quantities, represents an interesting starting material for other recycling products. The resources required to produce old batteries for electric vehicles, such as lithium, manganese, cobalt or nickel, are scarce, so it is advantageous if these raw materials remain as completely as possible in the recycling cycle at the end of the old battery's life. Therefore, the old batteries are broken down into their individual components wherever possible.This produces metal-containing black mass, which is a granulate mixture of the raw materials lithium, graphite and, depending on the type of used battery, metal and / or metal oxide such as cobalt, copper, nickel, manganese and / or iron (oxide). These ingredients can be separated from one another using conventional methods such as sieving and with the aid of magnets or hydrometallurgically, so that the black mass is available in a metal-free state. While the metals and metal oxides are used, for example, in the manufacture of new electric vehicle batteries, the metal-free black mass, which essentially consists of damaged graphite (i.e. graphite with defects or holes), is currently stored unused as waste or incinerated, producing climate-damaging CO2.It is an object of the invention to provide a method for refining and / or recycling black mass, in particular to process the metal-free black mass in such a way that the black mass obtained in the processing is suitable for further use beyond thermal utilization. The aim is to avoid combustion of the black mass to produce climate-damaging CO2. adares SUE-104-WO Graphite Recycling - 2 - According to the invention, this object is achieved by a method having the features of patent claim 1, a black mass having the features of patent claim 9, and a use having the features of patent claim 10. Further advantageous modifications and developments of the method are specified in subclaims 2 to 8.The invention relates to a method for refining and / or recycling black mass, comprising the following steps: a) providing a metal-free black mass, b) treating the metal-free black mass with a metal salt to obtain a black mass having a predetermined metal and / or metal oxide content, and / or c) adding a promoter element selected from the group consisting of N, P, S and / or B to the metal-free black mass or the black mass having a predetermined metal and / or metal oxide content. According to the invention, the metal-free black mass is provided either with a predetermined metal and / or metal oxide content and / or with a promoter element selected from the group consisting of N, P, S and / or B. The addition of the predetermined metal and / or metal oxide content ensures that a suitable performance of the black mass is achieved, for example when used as an electrode.The percentage composition of the metals and / or metal oxides is advantageously optimized so that the black mass with the predetermined metal and / or metal oxide content exhibits optimized and more reproducible performance. The added promoter element, which is selected from the group consisting of N, P, S, and / or B, acts – without wishing to be bound by any theory – as a foreign atom, particularly a promoter element atom, in the graphite of the black mass and stabilizes or "patches" holes in its structure. In graphite, the carbon atoms arrange themselves in the hexagonal pattern typical of carbon, thus forming a hexagonal layered lattice. In each layer, each carbon atom is bonded to three others, forming a two-dimensional network of hexagons.Within each layer there are strong bonds, but between the different layers the bonds are very weak, so that the layers can easily be shifted against each other and even separated. This influences the properties of the graphite. The addition of the promoter element stabilizes the graphite structure by occupying holes in the damaged structure. The addition of the promoter element can be made in amounts ranging from doping to substoichiometric. For the purposes of the invention, the term “metal-free black mass” refers to black mass that has a metal content of less than 0.01 wt.%. The metal-free black mass can be obtained, for example, from metal-containing black mass using wet-chemical processes and is commercially available, for example, from Duesenfeld GmbH (Wendeburg, Germany). Sonication is preferably carried out during step b) or c).By means of sonication, a higher yield, an accelerated reaction rate and / or milder reaction conditions can be achieved. Sonication therefore represents an efficient and harmless method for activating, promoting and accelerating the treatment carried out in the corresponding step. In a preferred embodiment, the metal salt used in step b) is selected from the group consisting of metal acetates and / or metal halides with a metal from the d- and / or f-block. Preferably, the metal from the d-block is an early and / or late transition metal, i.e., a transition metal from group IV, V, IX, and / or X. More preferably, the metal salt used in step b) is M(OAc)2 where M = Ni, Co, Fe or Mn or a mixture thereof.Preferably, the metal salt used in step b) is a mixture of adares SUE-104-WO graphite recycling - 4 - - Ni(OAc)2 with Fe(OAc)2, - Ni(OAc)2 with Co(OAc)2, - Co(OAc)2 with Fe(OAc)2, - Mn(OAc)2 with Co(OAc)2, or - Ni(OAc)2 with Fe(OAc)2 and Co(OAc)2. Preferably, a ratio of the individual metal salts of the mixture of Ni(OAc)2 with Fe(OAc)2, Ni(OAc)2 with Co(OAc)2, Co(OAc)2 with Fe(OAc)2 or Mn(OAc)2 with Co(OAc)2 is in the molar range of 9:1 to 1:9, more preferably 5:1 to 1:5, even more preferably 2:1 to 1:2. A ratio of Ni(OAc)2 : Fe(OAc)2 : Co(OAc)2 is, for example, 1 : 1 : 1. Preferably, the metal salt used in step b) is Fe(OAc)2 or a mixture of Ni(OAc)2 and Fe(OAc). 2.In a preferred embodiment, step c) is carried out by treating black mass with red phosphorus, S8, thiourea, urea, hydrazine, hydrazine sulfate, boric acid, diboron trioxide, or ammonia. Preferably, step c) is carried out once using one of the aforementioned starting materials. Alternatively, step c) can be repeated to add several promoter elements selected from the group consisting of N, P, S, and / or B to the black mass. The promoter element is selected from the group consisting of nitrogen, phosphorus, sulfur, and / or boron. Preferably, the promoter element is nitrogen and / or sulfur. More preferably, the promoter element is nitrogen. In a preferred embodiment, ammonia is used in step c). The addition of nitrogen to the black mass can increase performance.To add nitrogen to the graphite, the black mass is preferably heated in an ammonia gas stream as a nitrogen source for 1 hour or several hours, preferably 1 to 10 hours, at 200 to 400°C, more preferably 300-350°C. This verifiably absorbs nitrogen into the black mass. The detection of nitrogen in the adares SUE-104-WO Graphite Recycling - 5 - material can be demonstrated using XPS (X-ray photoelectron spectroscopy) emission spectra. Alternatively, the addition of nitrogen can be achieved using N2, urea, or hydrazine. Alternatively or additionally, the promoter element is preferably sulfur. The addition of sulfur leads to a drastic increase in the activity of the black mass, e.g., when used as a metal and / or metal oxide-containing electrode for hydrogen production in electrolytic water splitting.The addition of sulfur leads to a slight formation of metal sulfides such as NiS, CoS, and MnS if these metals are present in the black mass, which can promote electrolytic hydrogen formation. The addition of sulfur can be achieved, for example, using S8 or hydrogen sulfide. Simultaneous addition of sulfur and nitrogen can be achieved by reacting the black mass with thiourea, which simultaneously serves as a nitrogen and sulfur source. Alternatively or additionally, the promoter element is preferably phosphorus. The addition of phosphorus can be achieved, for example, using red phosphorus. Alternatively or additionally, the promoter element is preferably boron. The addition of boron can be achieved, for example, using boric acid or, preferably, diboron trioxide. Steps b) and c) are preferably carried out successively.In a preferred embodiment, step b) is carried out before step c). This means that metal(s) and / or metal oxide(s) are first added to the metal-free black mass in a predetermined amount, and then the promoter element is added to the black mass thus produced with the predetermined metal and / or metal oxide content. adares SUE-104-WO Graphite Recycling - 6 - Alternatively, step c) is preferably carried out before step b). This means that the promoter element is first added to the metal-free black mass, and then metal(s) and / or metal oxide(s) are added in the predetermined amount to the black mass thus produced containing the metal-free promoter element, in order to obtain the black mass containing the promoter element and having the predetermined metal and / or metal oxide content.In a preferred embodiment, following step a), step c) is carried out with ammonia as the promoter element, followed by step b) with Fe(OAc)2 or a mixture of Ni(OAc)2, Fe(OAc)2, and Co(OAc)2. This produces a black mass that exhibits high performance when used as an electrode in electrolytic water splitting. The metal-free black mass provided in step a) is preferably a commercially purchased black mass. The metal-free black mass is a material obtained from used batteries that have been used to electrically power an electric vehicle, preferably an electric car. In particular, the metal-free black mass is obtained by mechanical recycling through dismantling an old electric car battery to be recycled.After dismantling the housing and the device electronics of the used battery, mechanical recycling comprises several crushing, sorting, and classification steps of the remaining residue, from which, among other things, the metal-free black mass is extracted and processed. The black mass initially preferably comprises layer, electrode, and / or electrolyte materials from the used battery, preferably representing a granulate mixture. The active materials of the electrodes, such as graphite and lithium transition metal mixed oxides, such as cobalt, nickel, and manganese, are preferably enriched in the black mass. The composition of the black mass, however, depends on the chemical composition of the recycled used battery. There are various types of electric vehicle drive batteries that have different chemical compositions. The metal- and / or metal oxide-containing black mass can then, as mentioned above, for example,be converted by wet-chemical processes into a metal-free black mass in order to supply the metals and metal oxides for other uses. The metal-free black mass can be purchased, for example, from Duesenfeld GmbH (Wendeburg, Germany). The metal-free black mass provided in step a) can alternatively be obtained by exposing the likewise commercially available metal-containing black mass (Duesenfeld GmbH Wendeburg, Germany) to an inorganic acid. The inorganic acid is preferably H2SO4. The invention further relates to the black mass obtained by the process according to one or more of the embodiments described above. The black mass obtained by the process has either the one or more promoter elements and / or the predetermined metal and / or metal oxide content.The invention further relates to the use of the black mass obtained by the process as an electrode material, electrochemical catalyst, or heterogeneous catalyst. In a preferred embodiment, the black mass obtained by the process according to the invention is used as an electrode material. The black mass obtained by the process is preferably used as an electrode material for an anode or cathode for electrochemical use in water splitting to produce hydrogen and oxygen. The electrode material is preferably part of the working electrode used to produce oxygen or hydrogen. In a preferred embodiment, the black mass obtained by the process according to the invention is used as an electrochemical catalyst.adares SUE-104-WO Graphite Recycling - 8 - In a preferred embodiment, the black mass obtained by the process according to the invention is used as a heterogeneous catalyst. The invention is explained in more detail below with reference to the attached drawings and examples. These are shown schematically and not to scale: Fig. 1 shows an X-ray powder diffractogram of a black mass after treatment with H2SO4 or NH3; Fig. 2 shows a cyclic voltammogram of a black mass according to a first embodiment, which is used as a working electrode for producing oxygen; Fig. 3 shows a chronopotentiometry of the black mass according to a first embodiment, which is used as a working electrode for producing oxygen; Fig. 4 shows a cyclic voltammogram of a black mass according to a second embodiment, which is used as a working electrode for producing oxygen; Fig.5 shows a chronopotentiometry of the black mass according to a second embodiment, which is used as a working electrode for producing oxygen; Fig. 6 shows a cyclic voltammogram of the black mass according to a first embodiment, which is used as a working electrode for producing hydrogen; Fig. 7 shows a chronopotentiometry of the black mass according to a first embodiment, which is used as a working electrode for producing hydrogen; Fig. 8 shows a cyclic voltammogram of the black mass according to a second embodiment, which is used as a working electrode for producing hydrogen; Fig. 9 shows a chronopotentiometry of the black mass according to a second embodiment, which is used as a working electrode for producing hydrogen. adares SUE-104-WO Graphite Recycling - 9 - Fig. 1 shows an X-ray powder diffractogram of a black mass.The X-ray powder diffractogram shows a first X-ray powder diffractogram 1 of a metal-free black mass obtained according to Example 1 by treating a metal-containing black mass with H2SO4. Furthermore, Fig. 1 shows a second X-ray powder diffractogram 2 of a black mass obtained according to Example 2 below, which was obtained by treating a metal-free black mass with NH3. Fig. 2 shows a cyclic voltammogram of a black mass according to a first embodiment, which is used as a working electrode for producing oxygen during electrolytic water splitting, with a scan speed of 5 mV / s on Ni foam. The measurements according to a 2nd cycle and a 6th cycle were carried out in a three-electrode configuration. A Hg / HgO reference electrode was used, the potentials of which were referenced to the reversible hydrogen electrode (RHE).The black mass prepared according to Example 3 below was used as the electrode material for the working electrode. To prepare the working electrode, an electrolysis cell was prepared with one electrode based on a nickel foam and another electrode made of nickel foam in a solvent in the form of 10 ml of acetone. 25 mg of black mass and 2 mg of iodine were introduced into the solution. A voltage of 10 V was then applied to the electrodes at room temperature in air for a period of 30 s to 10 min. The 2 mg of iodine and 25 mg of black mass are sufficient to produce 10 to 15 working electrodes. The working electrodes prepared in this way are washed with organic solvent and dried in air. Fig. 3 shows a chronopotentiometry of the above working electrode at a current density of 100 mA / cm. 2The measurements were carried out on 1 x 1 cm Ni foam. adares SUE-104-WO Graphite Recycling - 10 - Fig. 4 shows a cyclic voltammogram of a black mass according to a second embodiment, which is used as a working electrode for producing oxygen during electrolytic water splitting, with a scan speed of 5 mV / s on Ni foam. The measurements according to a 2nd cycle and a 6th cycle were carried out in a three-electrode configuration. An Hg / HgO reference electrode was used, the potentials of which were related to the reversible hydrogen electrode (RHE). The black mass prepared according to Example 4 below was used as the electrode material for the working electrode. To produce the working electrode, an electrolysis cell was provided with an electrode based on a Ni foam and another electrode made of Ni foam in a solvent in the form of 10 ml of acetone.25 mg of black mass and 2 mg of iodine are introduced into the solution. A voltage of 10 V is then applied to the electrodes at room temperature in air for a period of 30 s to 10 min. The 2 mg of iodine and 25 mg of black mass are sufficient to produce 10 to 15 working electrodes. The working electrodes thus prepared are washed with an organic solvent and dried in air. Figure 5 shows a chronopotentiometry of the black mass according to a second embodiment, which is used as a working electrode for producing oxygen, as described for Figure 4, at a current density of 100 mA / cm. 2The measurements were carried out on 1 x 1 cm Ni foam. Fig. 6 shows a cyclic voltammogram of the black mass obtained by the process according to the first embodiment, which is used as a working electrode for producing hydrogen. A working electrode obtained as described for Fig. 2 was used as the working electrode. Fig. 7 shows a chronopotentiometry of the black mass obtained by the process according to a first embodiment, which is used as a working electrode for producing hydrogen, as described for Fig. 6, at a current density of -100 mA / cm 2The measurements were carried out on 1 x 1 cm Ni foam. Fig. 8 shows a cyclic voltammogram of the black mass according to the second embodiment, which is used as a working electrode for the production of hydrogen. The working electrode used was a working electrode obtained as described for Fig. 4. Fig. 9 shows a chronopotentiometry of the black mass according to the second embodiment, which is used as a working electrode for the production of hydrogen, as described for Fig. 8, at a current density of -100 mA / cm 2The measurements were carried out on 1 x 1 cm Ni foam Example 1 Production of a metal-free black mass The starting material used is a metal-containing black mass in the form of a recyclate from a used battery for the electrical drive of an electric vehicle, in particular an electric car. The recyclate is a recycled material based on an LFP accumulator (lithium iron phosphate accumulator) that was provided by Duesenfeld GmbH (Wendeburg, Germany). The one or more graphite-supported, noble metal-free metal oxides of the black mass contain iron oxide(s). The metal-containing components, i.e. iron oxide(s), are washed out of this metal-containing black mass using sulfuric acid to obtain metal-free black mass. For this purpose, the recyclate was ground and suspended in an aqueous solution of 2.5 M H2SO4 at 60°C for 5 h, then washed with water and acetone and dried in air.The X-ray powder diffractogram of the metal-free black mass thus obtained is shown in Fig. 1 as X-ray powder diffractogram 1. Example 2 adares SUE-104-WO Graphite Recycling - 12 - Addition of nitrogen as a promoter element The metal-free black mass obtained in Example 1 was heated in NH3 at 300 °C for 6 h in a furnace. The furnace was purged with NH3 before the heating process was started for 2 h and then heated at 300 K / h. Afterwards, it was cooled naturally to room temperature. The X-ray powder diffractogram of the metal-free black mass thus obtained is shown in Fig. 1 as X-ray powder diffractogram 2. Example 3 Addition of metal (oxide) and promoter element 100 mg of the metal-free black mass obtained in Example 1 was suspended in a solution of 10 ml of ethanol and 0.02 g of Fe(OAc)2 and sonicated for 2 h. The solvent was evaporated by a stream of N2 over a period of 2 h.The resulting product was ground and placed in a tube furnace, where the system was purged with NH3 for 1 h. The sample was then heated to 300 °C at 300 K / h and held at that temperature for 2 h before being allowed to cool naturally. Example 4: 100 mg of the black mass obtained in Example 2 was suspended in a solution of 10 ml of ethanol and 0.02 g of Fe(OAc)2 and sonicated for 2 h. The solvent was evaporated by a stream of N2 over a period of 2 h. The resulting product was ground and placed in a tube furnace, where the system was purged with N2 for 1 h. The sample was then heated to 300 °C at 300 K / h and held at that temperature for 2 h before being allowed to cool naturally. adares SUE-104 Graphite Recycling - 13 - List of reference symbols: 1 first X-ray powder diffractogram 2 second X-ray powder diffractogram 3 second cycle 4 sixth cycle.

Claims

adares SUE-104 Graphite Recycling - 14 - Claims:

1. A process for refining and / or recycling black mass, comprising the following steps: a) providing a metal-free black mass, b) treating the metal-free black mass with a metal salt to obtain a black mass with a predetermined metal and / or metal oxide content, and / or c) adding a promoter element selected from the group consisting of N, P, S, and / or B to the metal-free black mass or the black mass with the predetermined metal and / or metal oxide content.

2. The process according to claim 1, characterized in that sonication is carried out during step b) or c). 3.Process according to claim 1 or 2, characterized in that the metal salt used in step b) is selected from the group consisting of metal acetates and / or metal halides with a metal from the d- and / or f-block, wherein the metal salt used in step b) is preferably M(OAc)2with M = Ni, Co, Fe or Mn or a mixture thereof.

4. Process according to claim 3, characterized in that the metal salt used in step b) is a mixture of Ni(OAc)2 with Fe(OAc)2, Ni(OAc)2 with Co(OAc)2, Co(OAc)2 with Fe(OAc)2, Mn(OAc)2 with Co(OAc)2 or Ni(OAc)2 with Fe(OAc)2 and Co(OAc)2, wherein a ratio of the individual metal salts of the mixture of Ni(OAc)2 with Fe(OAc)2, Ni(OAc)2 with Co(OAc)2 or Mn(OAc)2 with Co(OAc)2 is preferably in the molar range from 9:1 to 1:

9.

5. Process according to one of the preceding claims, characterized in that step c) is carried out by treating black mass with. adares SUE-104 Graphite Recycling - 15 - red phosphorus, S8, thiourea, urea, hydrazine, hydrazine sulfate, boric acid, diboron trioxide, or ammonia, wherein step c) is optionally repeated.

6. The process according to claim 5, characterized in that ammonia is used in step c).

7. The process according to any one of the preceding claims, characterized in that step b) is carried out before step c) or that step c) is carried out before step b).

8. The process according to any one of the preceding claims, characterized in that the black mass provided in step a) is obtained by exposing a metal-containing black mass to an inorganic acid, wherein the inorganic acid is preferably H2SO4.

9. Black mass obtained by the process according to any one of the preceding claims. 10.Use of the black mass according to claim 9 as electrode material, electrochemical catalyst or as heterogeneous catalyst.

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