A method for obtaining a positive electrode active material from the black mass of a battery, and an apparatus for obtaining a positive electrode active material used in such a method.

Abstract

A method (10) for obtaining a positive electrode active material (CAM) from black mass (11) comprises the steps of: performing a leaching operation (L) on the black mass (11) using a leaching agent (12) to obtain a leachate (13); mixing the leachate (13) with supercritical water (16) (M1) to generate a nanoparticle precipitate to obtain a nanoparticle solution (17) of a metal oxide; mixing the nanoparticle solution (17) with an additive and / or a stream of cold water (18) (M2) to obtain a stoichiometrically accurate and / or chemically stable nanoparticle solution (19); and cooling the stoichiometrically equilibrated and / or chemically stable nanoparticle solution (19) (R) to obtain a positive electrode active material (CAM) and / or a precursor of a positive electrode active material (PCAM).

Description

Technical Field

[0001] The present invention relates to a method for obtaining a positive electrode active material from the black mass of a spent battery.

Background Art

[0002] The present invention also relates to an apparatus for obtaining a positive electrode active material, which can be used in such a method.

[0003] The term "black mass" refers in the industrial field to a kind of electronic waste derived from spent battery cells that have been crushed, shredded, and from which plastic parts, metal electrodes, and electrolytes have been removed. Black mass is composed of a negative electrode and a positive electrode active mixture.

[0004] Black mass contains a mixture of valuable metals including lithium (Li), manganese (Mn), cobalt (Co), and nickel (Ni).

[0005] In particular, black mass takes the form of a fine black powder and is composed of a carbon-containing fraction (lamp black, graphite), Li, a positive electrode active material (usually based on Ni and / or Mn and / or Co and / or aluminum (Al) and / or vanadium (V) and / or iron (Fe) and / or copper (Cu) and / or titanium (T) and / or zinc (Zn) and / or zirconium (Zr) and / or phosphate (PO4), etc.), an organic bond, and a solvent in very different ratios.

[0006] The organic fraction strongly depends on the mechanical separation process used, and in the state of the art, it is possible to minimize the organic content for about 85% of the recovered black mass.

[0007] The term "positive electrode active material" refers to a compound that is electrochemically active in that it has the ability to take in (intercalate) and deintercalate (deintercalate) lithium through spontaneous or induced oxidation reactions.

[0008] Recently, the demand for precious metals or metals of high economic value (especially lithium) has been increasing due to the considerable use of these materials in various industries, particularly the electronics and automotive sectors.

[0009] However, reserves of such metals are nearing depletion, and / or their extraction is complex, costly, and inconvenient.

[0010] Therefore, in recent years, the recovery of precious metals from black mass is becoming increasingly dominant as a means of obtaining cathode active materials.

[0011] For industry and lawmakers, the strategic need to recover lithium and implement recovery processes in accordance with stringent environmental sustainability parameters has led to a shift from high-temperature metallurgical thermal recovery processes to wet metallurgical wet recovery processes.

[0012] In the wet metallurgical recovery process, metals contained in black mass are extracted using a leaching process, usually starting with acid, which aims to solubilize the metals and separate them from the carbon-containing fraction.

[0013] Currently, the leaching process used is based on the use of sulfuric acid, which is effective in dissolving all cathode metals, lithium, and impurities.

[0014] Subsequently, purification processes such as chemical precipitation, electrolysis, or solvent extraction are carried out to separate impurities and obtain a pure fraction of the target metal (usually Co, Ni, or Li), typically in the form of heavy metal sulfates.

[0015] This purified compound is then continuously extracted in the solvent phase to obtain precipitates of heavy metal sulfates (such as Ni, Mn, and Co) and lithium carbonate (Li2CO3).

[0016] Lithium carbonate is a precursor used for the synthesis of positive electrode active materials and for lithium salts used in the electrolytes of lithium-ion batteries, which are commonly used to power mobile phones and laptop computers.

[0017] Lithium carbonate and heavy metal sulfates are then used in subsequent external methods to obtain the positive electrode active material.

[0018] Such prior art has several drawbacks. Firstly, in order to implement such a method for obtaining cathode active material starting from black mass, it is necessary to have a factory, which is quite complex from a technical and construction standpoint, and is quite expensive in terms of initial investment for construction as well as operating and maintenance costs.

[0019] Furthermore, such methods generate a massive amount of waste that must be discarded, comparable in quantity to the amount of positive electrode active material obtained, resulting in a significant environmental impact and considerable pollution. [Overview of the project] [Problems that the invention aims to solve]

[0020] The object of the present invention is to provide a method for obtaining a positive electrode active material from the black mass of a depleted battery, and an apparatus for obtaining a positive electrode active material that can be used in such a method, which can avoid the drawbacks of the prior art in one or more of the aspects described above.

[0021] Within the scope of this objective, the object of the present invention is to provide a method for obtaining a cathode active material from black mass that is simpler and more economical than similar conventional methods and apparatuses, and an apparatus for obtaining a cathode active material that can be used in such a method.

[0022] Another object of the present invention is to enable the reduction and / or elimination of the generation of waste to be discarded, thereby reducing the environmental impact compared to similar conventional methods and apparatuses, and to provide a method for obtaining a positive electrode active material from black mass, and an apparatus for obtaining a positive electrode active material that can be used in such a method.

[0023] Yet another object of the present invention is to overcome the drawbacks of the prior art in a manner that replaces any existing solutions.

[0024] Another object of the present invention is to provide a method for obtaining a positive electrode active material from the black mass of a spent battery, which is highly reliable, easy to implement, and low-cost, and an apparatus for obtaining a positive electrode active material that can be used in such a method.

Means for Solving the Problems

[0025] This objective and these and other objectives, which will become more apparent hereinafter, are achieved by a method for obtaining a positive electrode active material from black mass, comprising: performing a leaching operation on the black mass by using a leaching agent to thereby obtain a leachate; mixing the stoichiometrically accurate leachate with supercritical water to generate a nanoparticle precipitate, thereby obtaining a nanoparticle solution of metal oxide; mixing the nanoparticle solution with an additive and / or a flow of cold water to obtain a stoichiometrically accurate and / or chemically stable nanoparticle solution; cooling the stoichiometrically balanced and / or chemically stable nanoparticle solution to thereby obtain the positive electrode active material and / or a precursor of the positive electrode active material.

[0026] This objective and these and other objectives, which will become more apparent hereinafter, are achieved by an apparatus for obtaining a positive electrode active material, comprising: The first pump means, heating means downstream of the first pump means, the second pump means, the third pump means, the fourth pump means, a mixer, cooling means, a back pressure regulator, and is achieved by an apparatus characterized by including the above.

[0027] Further features and advantages of the present invention will become more apparent from the following detailed description of non-exclusive preferred embodiments of a method for obtaining a positive electrode active material from black mass and an apparatus for obtaining a positive electrode active material according to the present invention, shown as non-limiting examples in the accompanying drawings.

Brief Description of the Drawings

[0028] [Figure 1] It is a block diagram of a method for obtaining a positive electrode active material from black mass according to the present invention. [Figure 2] It is a diagram of an apparatus for obtaining a positive electrode active material according to the present invention.

Embodiments for Carrying Out the Invention

[0029] Referring to the drawings, a method 10 for obtaining a positive electrode active material from black mass according to the present invention is schematically shown by reference numeral 10.

[0030] Method 10 includes performing a leaching operation (denoted by L) on black mass 11 by using a leaching agent 12, thereby obtaining a leachate 13; performing a step M1 of mixing the leachate 13 with supercritical water 16 to generate a nanoparticle precipitate, thereby obtaining a nanoparticle solution 17 of metal oxide; performing a step M2 of mixing the nanoparticle solution 17 with a flow 18 of an additive and / or cold water to obtain a stoichiometrically accurate and / or chemically stable nanoparticle solution 19. The process comprises the steps of cooling such stoichiometrically accurate and / or chemically stable nanoparticle solution 19 (step R in Figure 1), thereby obtaining cathode active materials (CAM) and / or precursors of cathode active materials (PCAM).

[0031] In this specification, the term "leachate" refers to the solution resulting from the leaching process. In particular, the leaching agent 12 is one that is selectively selected from organic leaching agents such as organic and / or inorganic acids, and / or deep eutectic solvents, and / or combinations and / or arrangements of the said acids.

[0032] Furthermore, the use of organic leaching agents allows for the selective dissolution of the target metal against impurities remaining in the carbon-containing fraction.

[0033] Furthermore, the organic leaching agents are destroyed by the high temperatures of the supercritical process, so as not to generate by-products or waste that need to be discarded, and / or they themselves may be recovered materials, such as waste from the food industry.

[0034] Preferably, the leachate 12 is selected from citric acid, sulfuric acid and tartaric acid, lactic acid, oxalic acid, formic acid, acetic acid, or any similar acid, and / or a combination thereof.

[0035] In another illustrated embodiment, between the leaching operation L and the step M1 of mixing with supercritical water 16, there is a step of adding one or more precursors 14 of pure metals to the leached liquid 13 to correct the stoichiometry of the leached liquid 13, thereby obtaining a stoichiometrically accurate leached liquid 15.

[0036] Following the leaching step L and prior to the step of adding one or more precursors 14 of pure metal to the leaching solution 13, there is a filtration step F to remove solid residues containing undissolved or unprecipitated carbon-containing substances and metallic contaminants (such as copper, iron, aluminum, and zinc).

[0037] The pure metal precursor 14 is selected based on the desired results in terms of the chemical composition of the positive electrode active material CAM.

[0038] The step of adding one or more precursors 14 of pure metals to the leachate 13 is performed at the T confluence point (indicated by T).

[0039] In other embodiments not shown, the addition of one or more precursors 14 of pure metals to the leachate 13 may be carried out in different ways.

[0040] For example, it is possible to administer the deficient nickel salt as a solid in a mixing tank, or to administer a nickel solution inline.

[0041] Such a precursor 14 of pure metal allows for correction of the stoichiometry of the metal present in the leachate 13 by adding compounds required to address both the very large variability in the chemical composition of black mass and the various different chemical compositions required by the market, based on the intended use and the price of the raw materials.

[0042] For example, in the automotive sector, over the past decade, there has been a continuous shift towards chemical compositions with less cobalt due to significant price increases.

[0043] In particular, there was a stepwise transition from the NMC111 composition to the NMC532, NMC6221, and NMC811 compositions. These figures represent the molar ratios between nickel, manganese, and cobalt.

[0044] In this specification, "supercritical water" means water that is under a pressure higher than the critical pressure.

[0045] "Critical pressure" is the pressure at which a substance can exist in both gaseous and liquid states. Step M1, in which the stoichiometrically accurate leachate 15 is mixed with supercritical water 16, is carried out using a mixer of the type shown in Italian Patent No. 102019000000979 in the name of Particular Materials.

[0046] In particular, the mixer MIX shown in Figure 2, when considering the direction of flow of the mixed material, The first inlet 101 for the flow of supercritical water 16, A second inlet 102 for the stoichiometrically accurate flow of leachate 15, A mixing region (not shown) between the flow of supercritical water 16 and the flow of stoichiometrically accurate leachate 15, located downstream of the first inlet 101 and the second inlet 102, Downstream of the mixing region is an outlet 103 for the metal oxide nanoparticle solution 17 obtained from the mixture M1, The mixing region includes a connecting element (not shown) between a first inlet 101 and a second inlet 102, which is located upstream of the mixing region. This connecting element includes a chamber located at the second inlet 102, which surrounds the first inlet 101 and is in fluid communication with the mixing region, and narrows in the direction of the mixing region.

[0047] Advantageously, step M2, in which the nanoparticle solution 17 is mixed with an additive and / or a stream of cold water 18, may also serve to prevent the nanoparticles from adhering.

[0048] The present invention also relates to an apparatus 1, schematically shown in Figure 2, for obtaining a positive electrode active material according to the present invention.

[0049] Device 1 is, A first pumping means 21 for the flow of water 6, A heating means 22 for the flow of water 6 is located downstream of the first pumping means 21, A second pumping means 23 for the leachate 13, A third pumping means 24 for the flow of the pure metal precursor 14, A fourth pumping means 25 for the flow of additives and / or cold water 18, Mixer MIX and Cooling means RR, Back pressure regulator (BPR) and Includes.

[0050] The first pumping means 21, the second pumping means 23, the third pumping means 24, and the fourth pumping means 25 each include one or more pumps.

[0051] In particular, the first pumping means 21 and heating means 22 are located in the first hydraulic branch 31 of the apparatus 1 and are adapted to bring the flow of water 6 to a supercritical state 16.

[0052] The heating means 22 includes, for example, two heaters (not shown) in series, each having an electric heating element.

[0053] Each of those heaters is, A first heater adapted to raise the temperature of water 6 from approximately 20°C to approximately 450°C. This is a second heater adapted to raise the temperature of water 6 from approximately 450°C to approximately 650°C.

[0054] The second pumping means 23 is located in the first segment 32 of the second hydraulic branch 33 of the device 1.

[0055] The third pumping means 24 is located on the second segment 34 of the second hydraulic branch 33 of the apparatus 1, and the second segment 34 is parallel to the first segment 32.

[0056] The first segment 32 and the second segment 34 merge at the third segment 35 of the second hydraulic branch 33.

[0057] The third segment 35 of the second hydraulic branch 33 leads to the mixer MIX via the second inlet 102.

[0058] The first hydraulic branch 31 leads to the mixer MIX via the first inlet 101. The fourth pumping means 25 is located at the third hydraulic branch 36 of the device 1.

[0059] The outlet 103 of the mixer MIX is in fluid communication with the fourth hydraulic branch 37 of the apparatus 1. In particular, the fourth hydraulic branch 37 is For example, the fourth segment 38 in the output from the mixer MIX is composed of an INCONEL625 pipe approximately 1 meter long, It has a fifth segment 39 in which a cooling means RR and a back pressure regulator BPR are arranged.

[0060] The third hydraulic branch 36 is connected to the fourth hydraulic branch 37 in the interface region between the fourth segment 38 and the fifth segment 39 of the fourth hydraulic branch 37.

[0061] The cooling means RR includes, for example, two heat exchangers C1, C2 of the pipe-in-pipe and / or shell-and-tube and / or plate type.

[0062] The back pressure regulator BPR is positioned downstream of the cooling means RR, taking into account the direction of flow.

[0063] The back pressure regulator BPR is operated to allow the flow to reach an operating pressure of approximately 230 bar, and to reduce the pressure of the cooled flow downstream of the cooling means RR.

[0064] The operation of the apparatus 1 according to the present invention is as follows: The flow of leachate 13 is pre-mixed with the flow of pure metal precursor 14 at the T confluence point.

[0065] For the flow of the pure metal precursor 14, for example, a KOH solution is used, and its molar concentration is given by the following formula:

[0066]

number

[0067] The resulting stoichiometrically accurate flow of leachate 15 is then sent to the mixer MIX, where it meets the flow of supercritical water 16.

[0068] The turbulent mixing of these two flows results in a rapid deposition of nanoparticles 17 having the desired composition.

[0069] The resulting high-temperature dispersion of nanoparticles 17, for example exceeding 300°C, is cooled by a cooling means RR, depressurized using a back pressure regulator BPR, and collected in a container having a conical bottom.

[0070] The solid product, in the form of fine particles, is separated by filtration or centrifugation, washed and dried, and then sent to a calcination process designed to obtain an optimal particle size distribution for use as a positive electrode active material (CAM).

[0071] Furthermore, experimental tests have shown that the method and apparatus according to the present invention are as follows: - Excellent level of crystallinity and nanometer size, with no erroneous phases present. - Appropriate electrochemical performance levels in charge / discharge cycles for the application of synthetic materials as positive electrode active elements in lithium batteries. - No significant by-products are present in the residual water after particle separation. It is known that this can be obtained.

[0072] Furthermore, it should be noted that if such water contains significant residues of high-value metals, these could be reused in the leaching process.

[0073] Furthermore, it should be noted that, regardless of stoichiometric corrections, the method according to the present invention returns a mixed oxide of ultrafine metals, which is a very high-quality precursor of cathode active material PCAM for the cathode active material CAM production industry, without generating sulfate waste.

[0074] In this case, lithium is recovered in a manner that is essentially publicly known. Using stoichiometric corrections, To directly obtain the positive electrode active material CAM, Furthermore / or, to obtain a precursor of cathode active material PCAM, which can be converted to cathode active material CAM using a type of heat treatment that is essentially known, according to the stoichiometry and particle size distribution / morphology required by a particular application and / or market, That is also possible.

[0075] In practice, the present invention has proven to fully achieve its intended goals and objectives by providing a method for obtaining metal from black mass, and an apparatus for obtaining a cathode active material that can be used in such a method, which is simpler and more economical than similar conventional methods and apparatuses.

[0076] Furthermore, the present invention has been devised a method for obtaining metal from black mass, and an apparatus for obtaining a cathode active material that can be used in such a method, which makes it possible to reduce and / or eliminate the generation of waste that would otherwise be discarded, thereby resulting in a reduced environmental impact compared to similar conventional methods and apparatus.

[0077] The present invention, as conceived in this manner, is subject to numerous modifications and variations, all of which fall within the scope of the attached claims. Furthermore, all details may be replaced by other technically equivalent elements.

[0078] In practice, the materials used may be anything that conforms to the requirements and the latest technology, as long as they are suitable for the specific application, as well as the specified dimensions and shape.

[0079] The disclosure in Italian Patent Application No. 102023000007830, on which this application claims priority, is incorporated herein by reference.

[0080] Where a reference numeral follows a technical feature referred to in any claim, such reference numeral is inserted solely for the purpose of enhancing the clarity of the claim, and therefore has no limiting effect on the interpretation of each element identified by such reference numeral.

Claims

1. A method (10) for obtaining a positive electrode active material (CAM) from black mass (11), The steps include: performing an exudation operation (L) on the black mass (11) by using an exudate (12) to obtain an exudate (13); The step of mixing the aforementioned leachate (13) with supercritical water (16) (M １ The steps include: performing the following to generate a nanoparticle precipitate and thereby obtaining a nanoparticle solution of metal oxide (17); The step of mixing the nanoparticle solution (17) with an additive and / or a stream of cold water (18) (M ２ The steps include: performing the following to obtain a stoichiometrically accurate and / or chemically stable nanoparticle solution (19); Method (10), comprising the steps of cooling (R) the stoichiometrically equilibrated and / or chemically stable nanoparticle solution (19) to obtain the positive electrode active material (CAM) and / or a precursor of the positive electrode active material (PCAM).

2. The method according to claim 1 (10), characterized in that the leaching agent (12) is one of organic leaching agents selectively selected from organic and / or inorganic acids, and / or deep eutectic solvents, and / or combinations and / or arrangements of the acids.

3. The method according to one or more of the preceding claims (10), characterized in that the leachate (12) is selected from citric acid, sulfuric acid and tartaric acid, lactic acid, oxalic acid, formic acid, acetic acid, and / or combinations thereof.

4. The leaching operation (L) and the step (M) of mixing with supercritical water (16). １ The method according to one or more of the preceding claims (10), characterized in that between the above and the above, there is a step of adding one or more precursors (14) of pure metal to the leachate (13) in order to correct the stoichiometry of the leachate (13), thereby obtaining a stoichiometrically accurate leachate (15).

5. The method according to one or more of the preceding claims (10), characterized in that, after the leaching step (L) and before the step of adding one or more of the pure metal precursors (14) to the leaching liquid (13), there is a filtration step (F) for removing solid residues containing undissolved or unprecipitated carbon-containing substances and metal contaminants.

6. The method according to one or more of the preceding claims (10), characterized in that the step of adding one or more precursors (14) of a pure metal to the leachate (13) is performed at the T confluence point (T).

7. The step (M) involves mixing the stoichiometrically accurate leachate (15) with the supercritical water (16). １ ) is performed in a mixer (MIX), and the mixer (MIX) is designed to consider the direction of travel of the mixed flow, A first inlet (101) for the flow of the supercritical water (16), A second inlet (102) for the flow of the stoichiometrically accurate leachate (15), A mixing region between the flow of the supercritical water (16) and the flow of the stoichiometrically accurate leachate (15), the mixing region located downstream of the first inlet (101) and the second inlet (102), Downstream of the mixing region is an outlet (103) for the metal oxide nanoparticle solution (17), The method according to one or more of the preceding claims (10), comprising a connecting element between the first inlet (101) and the second inlet (102) located upstream of the mixing region, wherein the connecting element includes a chamber located at the second inlet (102) surrounding the first inlet (101), the chamber being in fluid communication with the mixing region and narrowing in the direction of the mixing region.

8. Apparatus (1) for obtaining a positive electrode active material (CAM), The first pumping means (21) and A heating means (22) located downstream of the first pump means (21), A second pumping means (23), A third pumping means (24), A fourth pumping means (25), Mixer (MIX) and Cooling means (RR), Back pressure regulator (BPR), Apparatus (1) characterized by including

9. The apparatus (1) according to claim 8, characterized in that the first pumping means (21), the second pumping means (23), the third pumping means (24), and the fourth pumping means (25) each include one or more pumps.

10. The apparatus (1) according to claim 8 or 9, characterized in that the first pumping means (21) and the heating means (22) are arranged in the first hydraulic branch (31) of the apparatus (1).

11. The apparatus (1) according to one or more of claims 8 to 10, characterized in that the heating means (22) includes two electrical resistance heaters in series.

12. The second pumping means (23) is located in the first segment (32) of the second hydraulic branch (33) of the apparatus (1), The third pumping means (24) is located on the second segment (34) of the second hydraulic branch (33) of the apparatus (1), and the second segment (34) is parallel to the first segment (32). The apparatus (1) according to one or more of claims 8 to 11, characterized in that the first segment (32) and the second segment (34) merge at the third segment (35) of the second hydraulic branch (33).

13. The aforementioned mixer (MIX) is designed considering the direction of the mixed flow. A first inlet (101) for the flow of supercritical water (16), A second inlet (102) for the stoichiometrically accurate flow of leachate (15), A mixing region between the flow of the supercritical water (16) and the flow of the stoichiometrically accurate leachate (15), located downstream of the first inlet (101) and the second inlet (102), Downstream of the mixing region is an outlet (103) for a metal oxide nanoparticle solution (17), Apparatus (1) according to one or more of claims 8 to 12, comprising a connecting element between the first inlet (101) and the second inlet (102) located upstream of the mixing region, wherein the connecting element includes a chamber located at the second inlet (102) that surrounds the first inlet (101), the chamber being in fluid communication with the mixing region and narrowing in the direction of the mixing region.

14. The third segment (35) of the second hydraulic branch (33) is connected to the mixer (MIX) via the second inlet (102), The apparatus (1) according to one or more of claims 8 to 13, characterized in that the first hydraulic branch (31) is connected to the mixer (MIX) via the first inlet (101).

15. The apparatus (1) according to one or more of claims 8 to 14, characterized in that the fourth pumping means (25) is located in the third hydraulic branch (36) of the apparatus (1).

16. The outlet (103) of the mixer (MIX) is in fluid communication with the fourth hydraulic branch (37) of the apparatus (1). The fourth hydraulic branch (37) is The fourth segment (38) in the output from the mixer (MIX), The cooling means (RR) and the back pressure regulator (BPR) are arranged in a fifth segment (39), The apparatus (1) according to one or more claims 8 to 15, characterized in that the third hydraulic branch (36) is connected to the fourth hydraulic branch (37) in the interface region between the fourth segment (38) and the fifth segment (39) of the fourth hydraulic branch (37).

17. The apparatus (1) according to one or more claims 8 to 16, characterized in that the cooling means (RR) includes two heat exchangers (C1, C2) of the pipe-in-pipe and / or shell-and-tube and / or plate type.

18. The apparatus (1) according to one or more claims 8 to 17, characterized in that the back pressure regulator (BPR) is arranged downstream of the cooling means (RR) when considering the direction of flow.

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