Black substance, method for refining and / or recovering black substance, and use of black substance
By treating the black substance with metal salts and adding accelerator elements to optimize it, the problem of utilizing non-metallic black substances has been solved, enabling its high-performance application in water electrolysis and avoiding CO2 emissions.
Patent Information
- Application Number
- CN202480030387.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-09
- Filing Date
- 2024-03-11
- Publication Date
- 2025-12-26
AI Technical Summary
In existing technologies, non-metallic black materials are left idle or incinerated, resulting in harmful CO2 emissions and failing to be effectively utilized for other purposes.
By using metal salt treatment and/or adding accelerator elements such as N, P, S, and B, the composition of the black material is optimized, thereby improving its performance as an electrode material.
A black substance suitable for applications other than heat recovery was prepared, avoiding harmful CO2 emissions and improving its performance in water electrolysis.
Smart Images
Figure CN121219232A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for refining and / or recycling a ferrous substance, a ferrous substance, and its uses. The ferrous substance primarily originates from the recycling of used electric vehicle batteries. With increasing production, this substance has become an important raw material for the preparation of other recycled products. Resources used in the production of used electric vehicle batteries, such as lithium, manganese, cobalt, or nickel, are scarce resources. Therefore, it is advantageous to retain these raw materials as completely as possible within the resource recycling system at the end of the battery's lifespan. Background Technology
[0002] Therefore, used batteries are broken down into their individual components as much as possible. This process produces a metallic black substance, a particulate mixture composed of lithium, graphite, and, depending on the type of used battery, metals and / or metal oxides such as cobalt, copper, nickel, manganese, and / or iron (oxides). These components can be separated from each other using traditional methods such as sieving, magnetic separation, or hydrometallurgy to obtain a metallic-free black substance. The metals and metal oxides can be used to manufacture new electric vehicle batteries, while the metallic-free black substance, currently composed primarily of damaged graphite (i.e., graphite with defects or pores), is left as waste or incinerated, generating harmful CO2. Summary of the Invention
[0003] The purpose of this invention is to provide a method for refining and / or recycling black substances to prepare, in particular, metal-free black substances, so that the prepared black substances are suitable for uses other than heat recovery, and to avoid the generation of climate-harmful CO2 from burning black substances.
[0004] According to the invention, this objective is achieved by the method having the features of claim 1, the black substance having the features of claim 9, and the use having the features of claim 10. Other advantageous modifications and further embodiments of the method of the invention are described in dependent claims 2 to 8.
[0005] This invention relates to a method for refining and / or recycling a black substance, comprising the following steps:
[0006] a) Provide a black substance that does not contain metals;
[0007] b) Treat the metal-free black substance with a metal salt to obtain a black substance having a predetermined metal and / or metal oxide content; and / or
[0008] c) Adding an accelerator element selected from the N, P, S and / or B groups to a metal-free black substance or a black substance having a predetermined content of metal and / or metal oxides.
[0009] According to the present invention, a metal-free black material can be added with a predetermined content of metals and / or metal oxides and / or doped with a accelerator element selected from N, P, S, and / or B. By adding a predetermined content of metals and / or metal oxides, suitable properties can be achieved when the black material is used, for example, as an electrode. The percentage composition of the metals and / or metal oxides is optimized so that the black material containing the predetermined content of metals and / or metal oxides has optimized and reproducible properties. The added accelerator element (selected from nitrogen, phosphorus, sulfur, and / or boron) – although not bound by a specific theory – can act as foreign atoms, especially as accelerator element atoms within the graphite structure of the black material, to stabilize or “fill” vacancies in its structure. In graphite, carbon atoms are arranged in a hexagonal pattern characteristic of carbon, forming a hexagonal lattice layer structure. In each layer, each carbon atom is bonded to three other carbon atoms, forming a two-dimensional hexagonal network. The chemical bonds within each layer are strong, but the bonds between different layers are very weak, so these layers can easily slip or even separate, thus affecting the properties of graphite. Adding accelerator elements can fill vacancies in damaged structures, thereby stabilizing the graphite structure. The amount of accelerator element added can be within the substoichiometric range.
[0010] In this invention, "metal-free black material" refers to a black material with a metal content of less than 0.01% by weight. Metal-free black materials can be obtained from metal-containing black materials through wet chemical processes, and can be purchased, for example, from Duesenfeld GmbH (Wyndberg, Germany).
[0011] During step b) or c), sonication is preferentially performed. Sonication allows for higher yields, faster reaction rates, and / or milder reaction conditions. Therefore, sonication is an effective and harmless method for activating, promoting, and accelerating the treatment performed in the corresponding step.
[0012] In a preferred embodiment, the metal salt used in step b) is selected from the metal acetate and / or metal halide groups of a metal in the d-block and / or f-block. Preferably, the metal in the d-block is an early and / or late transition metal, i.e., a transition metal from groups 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.
[0013] Preferably, the metal salt used in step b) is a mixture consisting of the following components:
[0014] - Ni(OAc)2 and Fe(OAc)2,
[0015] - Ni(OAc)2 and Co(OAc)2,
[0016] - Co(OAc)2 and Fe(OAc)2,
[0017] - Mn(OAc)2 and Co(OAc)2, or
[0018] - Ni(OAc)2 with Fe(OAc)2 and Co(OAc)2.
[0019] In a metal salt mixture composed of Ni(OAc)₂ and Fe(OAc)₂, Ni(OAc)₂ and Co(OAc)₂, Co(OAc)₂ and Fe(OAc)₂, or Mn(OAc)₂ and Co(OAc)₂, the molar ratio between the metal salts is preferably 9:1 to 1:9, more preferably 5:1 to 1:5, and most preferably 2:1 to 1:2. For example, the ratio of Ni(OAc)₂: Fe(OAc)₂: Co(OAc)₂ can be 1:1:1.
[0020] In step b), it is preferable to use the metal salt Fe(OAc)2 or a mixture of Ni(OAc)2 and Fe(OAc)2.
[0021] In a preferred embodiment, step c) is performed by treating the black substance with red phosphorus, S8, thiourea, urea, hydrazine, hydrazine sulfate, boric acid, boron trioxide, or ammonia. Preferably, step c) is performed once using one of the above-mentioned raw materials. Alternatively, step c) can be repeated to add a variety of accelerator elements selected from N, P, S, and / or B to the black substance.
[0022] The accelerator element is selected from the group consisting of nitrogen, phosphorus, sulfur, and / or boron. Nitrogen and / or sulfur are preferred accelerator elements. Nitrogen is the most preferred accelerator element.
[0023] In a preferred embodiment, ammonia is used in step c). Performance can be improved by adding nitrogen to the black material. To add nitrogen to the graphite, the black material is preferably heated in an ammonia gas stream as the nitrogen source for 1 hour or several hours, preferably 1 to 10 hours, at a temperature of 200 to 400°C, more preferably 300-350°C. This confirms the absorption of nitrogen by the black material. The presence of nitrogen in the material can be confirmed by XPS (X-ray photoelectron spectroscopy) emission spectroscopy. Alternatively, nitrogen can be added using N2, urea, or hydrazine.
[0024] Sulfur is preferred as a promoter element, either alternatively or additively. Adding sulfur significantly enhances the activity of the black material, for example, when it is used as an electrode containing metals and / or metal oxides for hydrogen production during water electrolysis. In the case of sulfur addition, if the black material contains metals such as nickel, cobalt, or manganese, small amounts of metal sulfides, such as NiS, CoS, and MnS, are formed, which contribute to the electrolytic hydrogen production reaction. Sulfur addition can be achieved, for example, by using S8 or hydrogen sulfide.
[0025] The simultaneous addition of sulfur and nitrogen can be achieved by reacting the black substance with thiourea, which serves as both a nitrogen and sulfur source.
[0026] Phosphorus is preferred as an accelerator element for substitution or addition. The addition of phosphorus can be achieved, for example, by using red phosphorus.
[0027] Boron is preferred as the accelerator element for substitution or addition. The addition of boron can be achieved, for example, by using boric acid or, more preferably, boron trioxide.
[0028] Steps b) and c) are preferably performed sequentially. In a preferred embodiment, step b) is performed before step c), that is, a predetermined amount of metal and / or metal oxide is first added to the metal-free black substance, and then an accelerator element is added to the resulting black substance having a predetermined content of metal and / or metal oxide.
[0029] Alternatively, step c) is preferably performed before step b), that is, the accelerator element is first added to the metal-free black substance, and then a predetermined amount of metal and / or metal oxide is added to the resulting black substance containing the accelerator element but not metal, to obtain a black substance containing the accelerator element and having a predetermined content of metal and / or metal oxide.
[0030] In a preferred embodiment, step c) is performed after step a), using ammonia as a promoter, followed by step b), using Fe(OAc)₂ or Ni(OAc)₂, or a mixture of Fe(OAc)₂ and Co(OAc)₂. This produces a black substance that exhibits high performance when used as an electrode in the water electrolysis reaction.
[0031] The metal-free black material provided in step a) is preferably a commercially available black material. This metal-free black material is a material obtained from spent electric vehicle drive batteries. In particular, it is obtained through mechanical recycling of spent electric vehicle batteries. The mechanical recycling process includes multiple crushing, sorting, and grading steps on the remaining parts after disassembling the battery casing and its electronic control unit, thereby obtaining and purifying the metal-free black material. In its initial stage, the black material comprises layered materials, electrode materials, and / or electrolyte materials from the spent battery, preferably in the form of a particulate mixture. Preferably, the black material is rich in active electrode materials, such as graphite and lithium transition metal composite oxides, such as cobalt, nickel, and manganese. The specific composition of the black material depends, of course, on the chemical composition of the recycled spent battery. Different types of electric vehicle drive batteries have different chemical compositions. The black material containing metals and / or metal oxides can be converted into a metal-free black material through, for example, a wet chemical process as described above, so that the metals and metal oxides can be used for other purposes. The metal-free black substance can be obtained, for example, from Duesenfeld GmbH (Wyndberg, Germany). Alternatively, the metal-free black substance used in step a) can also be prepared by exposing a metal-containing black substance, also available from Duesenfeld GmbH (Wyndberg, Germany), to an inorganic acid. The inorganic acid is preferably H₂SO₄.
[0032] The present invention also relates to a black substance obtained by the method according to one or more of the above embodiments. The black substance obtained according to the method has one or more accelerator elements and / or a predetermined content of metals and / or metal oxides.
[0033] Furthermore, the present invention relates to the use of the black substance obtained according to the method as an electrode material, an electrochemical catalyst, or a heterogeneous catalyst.
[0034] In a preferred embodiment, the black substance obtained by the method of the present invention is used as an electrode material. Preferably, the black substance obtained by this method is used as an electrode material for the anode or cathode in a water electrolysis reaction to produce hydrogen and oxygen. This electrode material is preferably part of the working electrode for producing oxygen or hydrogen.
[0035] In a preferred embodiment, the black substance obtained by the method of the present invention is used as an electrochemical catalyst.
[0036] In a preferred embodiment, the black substance obtained by the method of the present invention is used as a heterogeneous catalyst. Attached Figure Description
[0037] The invention will now be described in more detail with reference to the accompanying drawings and examples. The drawings are schematic and not to scale.
[0038] Figure 1 shows the X-ray powder diffraction pattern of the black substance after treatment with H2SO4 or NH3.
[0039] Figure 2 This is a cyclic voltammogram of the black substance in the first embodiment, which is used as the working electrode for oxygen generation.
[0040] Figure 3 This is a time-history potential diagram of the black substance in the first embodiment, which is used as the working electrode for oxygen generation.
[0041] Figure 4 is a cyclic voltammogram of the black material in the second embodiment, which is used as the working electrode for oxygen generation.
[0042] Figure 5 is a time history potential diagram of the black material in the second embodiment, which is used as the working electrode for oxygen generation.
[0043] Figure 6 is a cyclic voltammogram of the black material in the first embodiment, which is used as the working electrode for hydrogen production.
[0044] Figure 7 is a time-history potential diagram of the black material in the first embodiment, which is used as the working electrode for hydrogen production.
[0045] Figure 8 is a cyclic voltammogram of the black material in the second embodiment, which is used as the working electrode for hydrogen production.
[0046] Figure 9 is a time-history potential diagram of the black material in the second embodiment, which is used as the working electrode for hydrogen production. Detailed Implementation
[0047] Figure 1 shows the X-ray powder diffraction pattern of the black substance. The X-ray powder diffraction pattern displays the first X-ray powder diffraction curve 1 for the metal-free black substance, which was obtained according to Example 1 by treating a metal-containing black substance with H₂SO₄. Furthermore, Figure 1 also shows the second X-ray powder diffraction curve 2 for the black substance obtained according to Example 2 described later, which was obtained by treating a metal-free black substance with NH₃.
[0048] Figure 2 shows the cyclic voltammogram of the black material used as the working electrode for hydrogen production in the first embodiment, with measurements performed on Ni foam at a scan rate of 5 mV / s. Measurements in the second and sixth periods were performed in a three-electrode configuration. A Hg / HgO reference electrode was used, with potential conversion based on the reversible hydrogen electrode (RHE).
[0049] The black substance described in Example 3 below was used as the electrode material for the working electrode. To manufacture the working electrode, an electrolytic cell was prepared, equipped with one nickel foam-based electrode and another nickel foam-based electrode, using 10 ml of acetone as a solvent. 25 mg of the black substance and 2 mg of iodine were added to the solution. Then, a voltage of 10 V was applied to the electrode in air at room temperature for 30 s to 10 min. 2 mg of iodine and 25 mg of the black substance were sufficient to manufacture 10 to 15 working electrodes. The working electrodes thus prepared were washed with an organic solvent and dried in air.
[0050] Figure 3 shows the current density at 100 mA / cm². 2 The time-history potential of the aforementioned working electrode was measured. The measurements were performed on a 1 x 1 cm nickel foam.
[0051] Figure 4 shows the cyclic voltammogram of the black material used as the working electrode in the second embodiment for oxygen production during water electrolysis. The scan rate on the nickel foam was 5 mV / s. Measurements in the second and sixth periods were performed in a three-electrode configuration. A Hg / HgO reference electrode was used, with potential conversion based on a reversible hydrogen electrode (RHE).
[0052] The black substance described in Example 4 below was used as the electrode material for the working electrode. To manufacture the working electrode, an electrolytic cell was prepared, equipped with one nickel foam-based electrode and another nickel foam-based electrode, using 10 ml of acetone as a solvent. 25 mg of the black substance and 2 mg of iodine were added to the solution. Then, a voltage of 10 V was applied to the electrode in air at room temperature for 30 seconds to 10 minutes. 2 mg of iodine and 25 mg of the black substance were sufficient to manufacture 10 to 15 working electrodes. The working electrodes thus prepared were washed with an organic solvent and dried in air.
[0053] Figure 5 shows the time-history potential measurement results of the black material in the second embodiment, which was used as the working electrode for oxygen generation, as shown in Figure 4, with a current density of 100 mA / cm². 2The measurements were taken on a 1 x 1 cm nickel foam.
[0054] Figure 6 shows the cyclic voltammogram of the black material obtained according to the method of the first embodiment, which is used as the working electrode for hydrogen production. The working electrode used is the one fabricated as shown in Figure 2.
[0055] Figure 7 shows the time-history potential results of the black material obtained according to the method of the first embodiment. As shown in Figure 6, this black material was used as the working electrode for hydrogen production, with a current density of -100 mA / cm². 2 The measurements were taken on a 1 x 1 cm nickel foam.
[0056] Figure 8 shows the cyclic voltammogram of the black material in the second embodiment, which is used as the working electrode for hydrogen production. The working electrode used is the one fabricated as shown in Figure 4.
[0057] Figure 9 shows the time-history potential measurement results of the black material in the second embodiment. As described in Figure 8, this black material was used as the working electrode for hydrogen production, with a current density of -100 mA / cm². 2 The measurements were taken on a 1 x 1 cm nickel foam.
[0058] Example 1
[0059] Manufacturing metal-free black substances
[0060] A metallic black substance was used as the starting material, derived from the recycling of spent drive batteries from electric vehicles, particularly electric vehicles. The recycled material was based on LFP (lithium iron phosphate) batteries and supplied by Duesenfeld GmbH (Wyndberg, Germany). One or more metal oxides, including iron oxide, supported on graphite, were present in the black substance. The metallic components, i.e., iron oxide, were washed away from this metallic black substance with sulfuric acid to obtain a metallic-free black substance. For this purpose, the recycled material was ground, suspended in a 2.5 M aqueous solution of H₂SO₄ at 60°C for 5 hours, washed with water and acetone, and then dried in air. The X-ray powder diffraction pattern of the resulting metallic-free black substance is shown in Figure 1 as diffraction curve 1.
[0061] Example 2
[0062] Adding nitrogen as a accelerator element
[0063] The metal-free black substance obtained in Example 1 was heated in NH3 at 300 °C in a furnace for 6 hours. The furnace was first purged with NH3 before the heating process was started and continued for 2 hours at a rate of 300 K / h. Afterward, it was allowed to cool naturally to room temperature. The X-ray powder diffraction pattern of the metal-free black substance obtained in this way is shown in Figure 1 as diffraction curve 2.
[0064] Example 3
[0065] Add metal (oxide) and accelerator elements
[0066] 100 mg of the metal-free black substance obtained from Example 1 was suspended in 10 ml of ethanol and 0.02 g of Fe(OAc)₂ solution and sonicated for 2 h. The solvent was evaporated with a stream of N₂ for 2 h. The resulting product was ground, placed in a tube furnace, and washed with NH₃ for 1 h. The sample was then heated to 300 °C at a heating rate of 300 K / h, held at that temperature for 2 h, and then allowed to cool naturally.
[0067] Example 4
[0068] 100 mg of the black substance obtained from Example 2 was suspended in a solution of 10 ml ethanol and 0.02 g Fe(OAc)₂ and sonicated for 2 hours. The solvent was evaporated with a stream of N₂ for 2 hours. The product was ground, placed in a tube furnace, and rinsed with N₂ for 1 hour. The sample was then heated to 300 °C at a heating rate of 300 K / h, held at that temperature for 2 hours, and then allowed to cool naturally.
[0069] List of reference numerals in the attached diagram:
[0070] 1. First X-ray powder diffraction curve
[0071] 2. Second X-ray powder diffraction curve
[0072] 3. Second cycle
[0073] 4. Sixth cycle
Claims
1. A method for refining and / or recycling black substances, comprising the following steps: a) Provide a black substance that does not contain metals; b) Treating a metal-free black substance with a metal salt to obtain a black substance with a predetermined metal and / or metal oxide content; and / or c) Adding an accelerator element to a metal-free black substance or a black substance having a predetermined content of metal and / or metal oxides, wherein the accelerator element is selected from the group consisting of N, P, S and / or B.
2. The method according to claim 1, characterized in that, Ultrasonic irradiation is performed in step b) or c).
3. The method according to claim 1 or 2, characterized in that, The metal salt used in step b) is selected from the group of metal acetates and / or metal halides of a metal in region d and / or region f, wherein the metal salt used in step b) is preferably M(OAc)2, where M = Ni, Co, Fe or Mn, or a mixture thereof.
4. The method according to claim 3, characterized in that, The metal salt used in step b) is a mixture of Ni(OAc)2 and Fe(OAc)2, Ni(OAc)2 and Co(OAc)2, Co(OAc)2 and Fe(OAc)2, Mn(OAc)2 and Co(OAc)2, or Ni(OAc)2 and Fe(OAc)2 and Co(OAc)2. In the metal salt mixture of Ni(OAc)2 and Fe(OAc)2, Ni(OAc)2 and Co(OAc)2, or Mn(OAc)2 and Co(OAc)2, the molar ratio between the metal salts is preferably between 9:1 and 1:
9.
5. The method according to any one of the preceding claims, characterized in that, Step c) is accomplished by treating the black substance with red phosphorus, S8, thiourea, urea, hydrazine, hydrazine sulfate, boric acid, boron trioxide, or ammonia, wherein step c) may be repeated.
6. The method according to claim 5, characterized in that, Ammonia is used in step c).
7. The method according to any one of the preceding claims, characterized in that, Step b) is executed before step c), or step c) is executed before step b).
8. The method according to any one of the preceding claims, characterized in that, The black substance provided in step a) is obtained by exposing a metal-containing black substance to an inorganic acid, wherein the inorganic acid is preferably H2SO4.
9. The black substance obtained by the method according to any one of the preceding claims.
10. Use of the black substance of claim 9 as an electrode material, an electrochemical catalyst or a heterogeneous catalyst.