A lithium battery recycling material powder, its preparation method and application

Abstract

The present invention discloses a lithium battery recycling material powder, its preparation method and application, which relates to the technical field of battery recycling. The lithium battery recycling material powder includes a metal compound powder and an elemental carbon material. The metal compound powder includes at least one of the following elements: lithium, nickel, cobalt, manganese and iron; the separation index S of the lithium battery recycling material powder satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, where S = W DOC × BET, W DOC refers to the mass percentage of soluble organic carbon in the lithium battery recycling material powder. Soluble organic carbon refers to organic carbon that can be dissolved or dispersed in an aqueous solution with pH = 1 to 14; BET refers to the specific surface area of the lithium battery recycling material powder. When separating the positive electrode material and the negative electrode material in the lithium battery recycling material powder, the separation efficiency is relatively high. When performing hydrometallurgical extraction of valuable metals on the lithium battery recycling material powder, a good metal leaching rate is achieved in the acid leaching stage.

Description

Technical Field

[0001] The present invention relates to the technical field of battery recycling, and in particular to a lithium battery recycling material powder and a preparation method and application thereof. Background Art

[0002] With the rapid advancement of technology, market demand for new energy, especially new energy vehicles, continues to expand. As a core component, lithium batteries have gained widespread use. However, the resulting issue of disposing of retired batteries has become a bottleneck in the industry's development. This has led to the development of lithium battery recycling material powder (black powder, Black Mass) technology, which recycles valuable metals and other materials from used batteries for reuse, achieving a green transformation from waste to treasure. Lithium battery recycling material powder primarily comes from the disassembly, crushing, and screening of used lithium batteries. Its main components include valuable metals such as lithium, cobalt, nickel, and manganese, as well as non-metallic materials such as carbon powder and plastic.

[0003] At present, the mainstream methods or research directions for the recovery and reuse of black powder include pyrometallurgy, hydrometallurgy, direct regeneration, etc. Pyrometallurgy refers to a metallurgical method that separates the metal from other impurities through high-temperature smelting and reduction reaction to obtain metal elements. This method has a low waste utilization rate and high energy consumption and pollution. It can only obtain metal alloys and is gradually being eliminated; hydrometallurgy refers to the ionization of metal elements, and then the separation and enrichment of metals through precipitation, electrolysis, extraction, ion exchange and other technologies. Finally, the target metal is recovered in the form of a certain chemical state. This method can obtain relatively pure metal compounds and can be directly used to prepare electrode materials. It is the current mainstream recycling method; direct regeneration refers to the targeted solution to the failure problem of the material without destroying the inherent structure of the material, realizing structural regeneration, and thus restoring the electrochemical activity of the material. This method has the lowest recycling cost and the lowest pollution in the recycling process, but the regeneration cost is high and the performance of the recycled material still does not meet the application requirements.

[0004] In the hydrometallurgical process, acid leaching is usually used to ionize metal elements. The acid leaching process requires the addition of hydrogen peroxide to promote the dissolution of metal ions, which will produce a large number of bubbles. On the one hand, when the acid leaching solution contains dissolved organic carbon (DOC), these DOC are equivalent to surfactants, making it difficult to eliminate bubbles and even causing bubbling, which greatly reduces the leaching efficiency. On the other hand, when the bubbles float to the liquid surface, they will carry away the black powder particles at the bottom of the kettle. When the porosity of the black powder particles is large (that is, the density is low), they tend to float on the liquid surface, resulting in a decrease in leaching efficiency.

[0005] Direct regeneration requires the separate recycling of the cathode material and the anode material in the black powder. Therefore, it is necessary to effectively separate the cathode material and the anode material in the black powder without damaging their inherent structures. The basis for separation is the difference in their water wettability and density. The organic matter remaining on the surfaces of the cathode material and anode material particles in the black powder will reduce the difference in their water wettability; if the porosity of the black powder particles is too high, it will cause the cathode material and / or anode material to deviate from their true density to a greater extent, making it more difficult to separate using density differences, thereby reducing the sorting effect.

[0006] In the process of treating battery or electrode sheet waste by physical or / and chemical methods to obtain black powder, it is of great significance to regulate the physical and chemical properties (such as organic matter content, specific surface area, particle size, etc.) of the black powder to obtain black powder with good separation effect of the cathode and anode materials and wet leaching efficiency for realizing the recycling of the black powder.

[0007] In view of this, the present invention is specifically proposed. Summary of the Invention

[0008] The purpose of the present invention is to provide a lithium battery recycling material powder, aiming to improve the metal leaching rate in the hydrometallurgy process and the separation efficiency of the cathode and anode materials during the regeneration process.

[0009] The present invention is implemented as follows:

[0010] In a first aspect, the present invention provides a lithium battery recycling material powder, including a metal compound powder and an elemental carbon material. The metal compound powder includes at least one of the following elements: lithium, nickel, cobalt, manganese, and iron; the separation index S of the lithium battery recycling material powder satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, where S = W DOC × BET, W DOC refers to the mass percentage of soluble organic carbon in the lithium battery recycling material powder; the soluble organic carbon refers to the organic carbon that can be dissolved or dispersed in an aqueous solution with a pH of 1 to 14; BET refers to the specific surface area of the lithium battery recycling material powder, with the unit of m 2 / g.

[0011] In some embodiments, the lithium battery recycling material powder satisfies at least one of the following characteristics I to IV:

[0012] Characteristic I: When the pH of the aqueous solution ≤ 3, the separation index S of the lithium battery recycling material powder satisfies 2 m 2 / kg ≤ S ≤ 24 m 2 / kg;

[0013] Feature 2: When the pH of the aqueous solution is ≥10, the separation index S of the lithium battery recycling material powder satisfies 13 m 2 / kg ≤ S ≤ 40 m 2 / kg;

[0014] Feature 3: The W of the lithium battery recycling material powder DOC is less than or equal to 15‰;

[0015] Feature 4: The BET of the lithium battery recycling material powder satisfies 1 m 2 / g ≤ BET ≤ 15 m 2 / g.

[0016] In some embodiments, the mass percentage of iron element in the lithium battery recycling material powder is 10% - 30%, and the BET of the lithium battery recycling material powder is 10 - 15 m 2 / g.

[0017] In some embodiments, the mass percentage of cobalt element in the lithium battery recycling material powder is 1% - 50%, and the BET of the lithium battery recycling material powder is 1 - 3 m 2 / g.

[0018] In some embodiments, the Dv50 of the lithium battery recycling material powder is 0.6 - 16 μm.

[0019] In some embodiments, the Dv10 of the lithium battery recycling material powder is 0.1 - 1.5 μm.

[0020] In some embodiments, the Dv10 of the lithium battery recycling material powder is 0.5 - 5.2 μm.

[0021] In some embodiments, the mass percentage of lithium element in the lithium battery recycling material powder is 0 - 10%.

[0022] In the second aspect, the present invention provides a preparation method of the lithium battery recycling material powder in any of the above embodiments, comprising the following steps:

[0023] Provide a lithium battery recycling crude material containing a negative electrode material, a positive electrode material, and an organic substance;

[0024] Perform photocatalytic oxidation treatment on the lithium battery recycling crude material to obtain a photocatalytic treatment intermediate;

[0025] Perform flash drying on the photocatalytic treatment intermediate to obtain a dried intermediate;

[0026] Perform heat treatment on the dried intermediate to obtain a heat treatment intermediate;

[0027] Cool down to below 20°C in an inert atmosphere, crush and screen to obtain the lithium battery recycling material powder.

[0028] In some embodiments, the positive electrode material includes at least one of lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate.

[0029] In some embodiments, the negative electrode material includes graphite.

[0030] In some embodiments, the organic matter includes a polymer compound obtained by reacting with carbon-carbon unsaturated bonds and an organic solvent. The polymer compound includes at least one of, but is not limited to, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyethylene (PE), and polypropylene (PP). The organic solvent includes at least one of, but is not limited to, ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and ethyl methyl carbonate.

[0031] Photocatalytic oxidation treatment refers to ultraviolet light irradiation of the crude lithium battery recycling material in an oxygen-containing or / and water-containing environment in the presence of a photocatalyst; in some embodiments, the photocatalyst includes at least one of titanium dioxide and zinc oxide; preferably, the photocatalyst is anatase titanium dioxide; preferably, the particle size of the photocatalyst is less than 500 nm and is supported on at least one of the following carriers: aluminum foil, ceramic, glass, silica, molecular sieve, and screen, aiming to facilitate the separation of the photoprocessing intermediate from the photocatalyst.

[0032] In some embodiments, the ultraviolet light irradiation conditions include: the light wavelength is 200 - 400 nm, and the irradiation time is 5 - 15 h.

[0033] In some embodiments, the environmental humidity of the photocatalytic oxidation treatment is maintained at 60% - 100%, and the environmental oxygen content is maintained at more than 30 vt%.

[0034] In some embodiments, the inlet air temperature of the flash drying is 200 - 400 °C, the outlet air temperature is 100 - 200 °C, the rotation speed is 10 - 30 Hz, and the feeding frequency is 10 - 30 Hz.

[0035] In some embodiments, the heat treatment is carried out under negative pressure, the temperature is 350 °C - 500 °C, the pressure is -0.01 - -0.05 MPa, and the time is 0.5 - 1.5 h.

[0036] In some embodiments, the cooling rate is 1 - 6 °C / min.

[0037] In some embodiments, the particle size of the crude lithium battery recycling material is less than 1 cm.

[0038] In some embodiments, the crude lithium battery recycling material is obtained by mechanically crushing battery waste through disassembly, stamping, grinding, shearing, etc.

[0039] In some embodiments, the battery waste includes but is not limited to used batteries, used battery cells, used battery jelly rolls, electrode sheet waste, and unqualified batteries on the production line.

[0040] In some embodiments, the light components in the battery waste, such as plastics, aluminum foils, copper foils, etc., are removed by means such as air separation, screening, density separation, optical separation, etc.

[0041] In some embodiments, the larger parts in the battery waste, such as the outer shell, wires, and sealing plates, can be separated by manual or automatic sorting. For example, magnetic components can be separated by a magnetic separator, and non-magnetic metals can be separated by an eddy current separator.

[0042] In a third aspect, the present invention provides the application of the lithium battery recycling material powder in any of the above embodiments.

[0043] The lithium battery recycling material powder is applied to hydrometallurgy, and the hydrometallurgy steps include: dispersing the lithium battery recycling material powder in an acid solution to obtain an acid-leached solution containing metal ions.

[0044] In some embodiments, the acid-leached solution is subjected to steps including but not limited to impurity removal, extraction, precipitation, and drying, etc., to obtain a product enriched with valuable metal elements, and the valuable metal elements include at least one of nickel, cobalt, manganese, lithium, and iron.

[0045] In some embodiments, the acid-leached solution is subjected to steps including but not limited to impurity removal, extraction, etc., to obtain an aqueous solution enriched with metal salts; the metal salts include at least one of nickel salts, cobalt salts, manganese salts, and lithium salts.

[0046] In some embodiments, the acid-leached solution is subjected to steps including but not limited to impurity removal, precipitation, carbonization, and drying, etc., to obtain lithium carbonate.

[0047] The lithium battery recycling material powder is applied to the regeneration of the cathode material, and the steps include: enriching the cathode material in the lithium battery recycling material powder by using a flotation separation method, and calcining the cathode material with lithium to obtain a regenerated cathode material.

[0048] The lithium battery recycling material powder is applied to the recycling of graphite, and the steps include: enriching the graphite in the lithium battery recycling material powder by using a flotation separation method, and recycling the graphite.

[0049] In some embodiments, the graphite is heat-treated to obtain a regenerated anode material.

[0050] In some embodiments, the graphite is used to prepare graphene.

[0051] The present invention has the following beneficial effects:

[0052] The present invention provides a lithium battery recycling material powder. The product of the soluble organic carbon content and the specific surface area of the lithium battery recycling material powder meets an appropriate range. The lithium battery recycling material powder within this range has a high separation efficiency when separating the positive electrode material and the negative electrode material; when applied to hydrometallurgy for extracting valuable metals, it has a good metal leaching rate in the acid leaching stage. Detailed Embodiments

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can all be obtained as conventional products through commercial purchase.

[0054] The present invention provides a lithium battery recycling material powder, including a metal compound powder and an elemental carbon material. The metal compound powder includes at least one of the following elements: lithium, nickel, cobalt, manganese, and iron; the separation index S of the lithium battery recycling material powder satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, where S = W DOC × BET, W DOC refers to the mass percentage of soluble organic carbon of the lithium battery recycling material powder; the soluble organic carbon refers to the organic carbon that can be dissolved or dispersed in an aqueous solution with pH = 1 - 14; BET refers to the specific surface area of the lithium battery recycling material powder, with the unit of m 2 / g.

[0055] The metal compound powder includes a positive electrode material, and the positive electrode material includes at least one of lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate; the metal compound powder is rich in valuable metals such as lithium, nickel, cobalt, manganese, and iron, and its recycling has economic significance and environmental significance.

[0056] The elemental carbon material includes graphitized carbon, such as graphite, graphene, carbon nanotubes, etc.; in some embodiments, the elemental carbon also includes non-graphite carbon, that is, amorphous carbon, such as carbon black, hard carbon, etc.

[0057] The lithium battery recycling material powder is a powder obtained by disassembling, crushing, sorting and other processes from waste lithium batteries, which is enriched with cathode materials and anode materials (graphite). The recycling methods include hydrometallurgy, direct regeneration, etc. Hydrometallurgy includes dispersing the lithium battery recycling material powder in an acid solution for acid leaching to obtain a post-acid leaching solution containing valuable metal ions. Some physicochemical properties of the lithium battery recycling material powder (such as particle size, specific surface area, composition, etc.) have a great influence on the acid leaching process. Direct regeneration first requires separating the metal compound powder and elemental carbon material in the lithium battery recycling material powder, and then calcining the metal compound powder with a lithium source to obtain a recycled cathode material; the elemental carbon material is recycled through heat treatment, oxidative exfoliation, coating and other means. Some physicochemical properties of the lithium battery recycling material powder (such as surface properties, density, particle size, etc.) have a great influence on the separation efficiency of the two.

[0058] The present invention provides a lithium battery recycling material powder, having a separation index S satisfying 0.15 m 2 / kg ≤ S = W DOC × BET ≤ 43 m 2 / kg. The lithium battery recycling material powder with a separation index within this range has good separation efficiency of the positive and negative electrode materials and metal leaching rate.

[0059] A lower W DOC can indirectly indicate that there is less residual organic carbon in the lithium battery recycling material powder. The sources of organic carbon include undepleted electrolyte, binder, decomposition products of electrolyte and binder, and external contaminated carbon sources, etc. The residual amount and type of organic matter are related to the process parameters when obtaining the lithium battery recycling material powder. For example, the higher the calcination temperature and the longer the calcination time, the less the residual organic carbon; another example is that adding additives to promote the decomposition and gasification of organic matter results in less residual organic carbon, etc.

[0060] On the one hand, the lithium battery recycling material powder with a lower W DOC is not prone to overflow during the acid leaching process and is beneficial to improving the metal leaching rate. Because the organic matter dissolved during the acid leaching process (i.e., W DOC ) is equivalent to a surfactant, making it difficult for the bubbles generated during the acid leaching process to defoam. The bubbles are easy to carry the material powder away from the liquid phase, thereby reducing the metal leaching rate. Too many bubbles are prone to overflow, reducing the production controllability. On the other hand, the lithium battery recycling material powder with a lower W DOC has good separation efficiency of the positive and negative electrode materials. Because the positive and negative electrode materials are usually separated by using the hydrophilic-hydrophobic difference and density difference of the powder particles. If there is too much residual organic matter in the lithium battery recycling material powder, the hydrophilic-hydrophobic difference on the surface of the positive and negative electrode materials will be lower, making it difficult to separate. Therefore, the lower the W DOC , the better the quality of the lithium battery recycling material powder.

[0061] The BET is the specific surface area of the lithium battery recycling material powder. Within a certain range, the larger the BET, the higher the metal leaching rate during the hydrometallurgical process. However, if it is too large, it is not conducive to improving the metal leaching rate. Specifically, a too large BET indicates that the particle size of the powder is too small or the powder has a rich pore structure. A too small particle size will cause the powder to easily float on the liquid surface, reducing the contact with the acid solution; too many pores result in a smaller density of the powder, making it easier to float on the liquid surface and reducing the contact with the acid solution. In summary, there is an appropriate range of BET that is beneficial to improving the metal leaching rate of the lithium battery recycling material powder in hydrometallurgy.

[0062] On the other hand, a too small BET indicates that the particle size of the lithium battery recycling material powder is large and the internal pore structure of the particles is small, usually caused by a high degree of agglomeration of the lithium battery recycling material powder (organic matter residues or amorphous carbon obtained after its carbonization serves as a binder to bind the powder together). This will lead to difficulty in separating each component, and the purity of the separated product is low. A too large BET indicates that the particle size of the lithium battery recycling material powder is too small or the pore structure is too much (the more pores, the higher the deviation from the true density). Since the density and particle size of graphite are usually smaller than those of the cathode material, a too large BET will result in a reduced difference between graphite and the cathode material, making it difficult and less controllable to separate the positive and negative electrode materials in the lithium battery recycling material powder using density differences or mass differences. In summary, there is an appropriate range of BET that is beneficial to improving the separation of the positive and negative electrode materials in the lithium battery recycling material powder.

[0063] Since W DOC and BET have the same trend of influence on both the metal leaching rate and the separation efficiency of the positive and negative electrode materials, the separation index S = W DOC × BET comprehensively reflects the separation ability of each component in the lithium battery recycling material powder. The lithium battery recycling material powder with 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg has good separation efficiency of the positive and negative electrode materials and metal leaching rate.

[0064] It should be noted that DOC (Dissolved Organic Carbon) refers to the content of organic carbon dissolved or dispersed in the aqueous solution of the lithium battery recycling material powder. The aqueous solution includes aqueous solutions with pH = 1 - 14; it was found during the experiment that the W DOC of the lithium battery recycling material powder varies at different pH values. Since the acid leaching in hydrometallurgy is usually carried out at a pH below 3, and the flotation separation is usually carried out at a pH greater than 7, therefore, measuring the W DOC of the lithium battery recycling material powder in each pH range is beneficial to comprehensively evaluate its separation index.

[0065] It should be noted that the separation index S of the lithium battery recycling material powder measured at any pH value from 1 to 14 satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, which are all within the protection scope defined by the present invention. For example, when the pH of a certain lithium battery recycling material powder is ≤ 3, it satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, and when the pH ≥ 10, it does not satisfy 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg and is still within the protection scope of the present invention.

[0066] In some embodiments, when the pH of the aqueous solution is ≤ 3, the separation index S of the lithium battery recycling material powder satisfies 2 m 2 / kg ≤ S ≤ 24 m 2 / kg. The lithium battery recycling material powder within this range has a good metal leaching rate during the acid leaching process of hydrometallurgy, which is beneficial to improving the metal recovery rate of hydrometallurgy; the separation index S of the lithium battery recycling material powder can be 2.03 m 2 / kg ≤ S ≤ 10.2 m 2 / kg, 10.2 m 2 / kg ≤ S ≤ 15 m 2 / kg, 15 m 2 / kg ≤ S ≤ 23.95 m 2 / kg, etc. or any value within the range.

[0067] In some embodiments, when the pH of the aqueous solution is ≥ 10, the separation index S of the lithium battery recycling material powder satisfies 13 m 2 / kg ≤ S ≤ 40 m 2 / kg. The lithium battery recycling material powder within this range has a good separation efficiency when separating the positive and negative electrode materials by flotation, which is beneficial to improving the recovery utilization rate of the positive and negative electrode materials; the separation index S of the lithium battery recycling material powder can be 13 m 2 / kg ≤ S ≤ 20 m 2 / kg, 20 m 2 / kg ≤ S ≤ 26.5 m 2 / kg, 26.5 m 2 / kg ≤ S ≤ 38.6 m 2 / kg, etc. or any value within the range.

[0068] In some embodiments, the W of the lithium battery recycling material powder DOC is less than or equal to 15‰. The lithium battery recycling material powder within this W DOC range has a good metal leaching rate and positive and negative electrode material separation efficiency; the W of the lithium battery recycling material powderDOC It can be a value within the ranges of 0 to 0.6‰, 0.6‰ to 1.7‰, 1.7‰ to 2.8‰, 5‰ to 9.5‰, 7‰ to 13.5‰, etc., or any value within a certain range.

[0069] In some embodiments, the mass percentage of iron element in the lithium battery recycling material powder is 10% - 30%, W DOC lower than 3‰; for example, the mass percentage of iron element in the lithium battery recycling material powder can be 10% - 15%, 15% - 20%, 20% - 30%, etc., or any value within a certain range.

[0070] In some embodiments, the mass percentage of cobalt element in the lithium battery recycling material powder is 1% - 50%, W DOC is 5‰ - 15‰; for example, the mass percentage of cobalt element in the lithium battery recycling material powder can be 1% - 5%, 5% - 10%, 10% - 30%, 30% - 50%, etc., or any value within a certain range.

[0071] In some embodiments, when the pH of the aqueous solution ≤ 3, the W of the lithium battery recycling material powder DOC is lower than 10‰.

[0072] In some embodiments, when the pH of the aqueous solution ≥ 10, the W of the lithium battery recycling material powder DOC is 7‰ - 14‰.

[0073] In some embodiments, the BET of the lithium battery recycling material powder satisfies 1m 2 / g ≤ BET ≤ 15m 2 / g.

[0074] In some embodiments, the mass percentage of iron element in the lithium battery recycling material powder is 10% - 30%, and the BET of the lithium battery recycling material powder is 10 - 15m 2 / g.

[0075] In some embodiments, the mass percentage of cobalt element in the lithium battery recycling material powder is 1% - 50%, and the BET of the lithium battery recycling material powder is 1 - 3m 2 / g.

[0076] In some embodiments, the Dv50 of the lithium battery recycling material powder is 0.6 - 16μm. The particle size of the lithium battery recycling material powder has an impact on its BET. The smaller the particle size, the larger the BET, that is, the larger the separation index S; the larger the particle size, the smaller the BET, that is, the smaller the separation index S. The Dv50 of the lithium battery recycling material powder can be 0.6 - 4.08μm, 4.08 - 7.64μm, 7.64 - 10μm, 10 - 16μm, etc., or any value within a certain range.

[0077] In some embodiments, the Dv10 of the lithium battery recycling material powder is 0.1 - 1.5 μm, for example, it can be 0.1 - 0.73 μm, 0.74 - 0.93 μm, 1.0 - 1.5 μm, etc. or any value within the range; the lithium battery recycling material powder within this range avoids too large or too small BET, thus affecting its application performance. For example, during hydrometallurgy, it can avoid too much powder floating on the liquid surface and reducing the metal leaching rate, etc.

[0078] In some embodiments, the Dv10 of the lithium battery recycling material powder is 0.5 - 5.2 μm, for example, it can be 0.5 - 1.5 μm, 1.52 - 2.32 μm, 2.32 - 5.2 μm, etc. or any value within the range; the lithium battery recycling material powder with Dv10 within this range avoids too large or too small BET, thus affecting its application performance. For example, during hydrometallurgy, it can avoid too much powder floating on the liquid surface and reducing the metal leaching rate, etc.

[0079] In some embodiments, the mass percentage of lithium element in the lithium battery recycling material powder is 0 - 10%, for example, the mass percentage of lithium element in the lithium battery recycling material powder can be 1% - 3%, 3% - 5%, 5% - 10%, etc. or any value within the range.

[0080] The present invention provides a preparation method of the lithium battery recycling material powder in any of the above embodiments. During the preparation process, organic matters are removed as much as possible, and process conditions are controlled so that the lithium battery recycling material powder has an appropriate BET and its separation index S meets the requirements. Specifically, the following method can be adopted for preparation, but it is not limited to the method provided in the embodiments of the present invention.

[0081] A preparation method of a lithium battery recycling material powder includes the following steps:

[0082] Provide lithium battery recycling crude materials containing negative electrode materials, positive electrode materials, and organic matters;

[0083] Perform photocatalytic oxidation treatment on the lithium battery recycling crude materials to obtain a photo - treatment intermediate;

[0084] Perform flash drying on the photo - treatment intermediate to obtain a dried intermediate;

[0085] Perform heat treatment on the dried intermediate to obtain a heat - treated intermediate;

[0086] Cool down to below 20°C in an inert atmosphere, crush and screen to obtain the lithium battery recycling material powder.

[0087] In some embodiments, the positive electrode material includes at least one of lithium cobalt oxide, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate.

[0088] In some embodiments, the negative electrode material includes graphite.

[0089] In some embodiments, the organic matter includes a polymer compound obtained by reacting with a carbon-carbon unsaturated bond and an organic solvent. The polymer compound includes at least one of, but is not limited to, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyethylene (PE), and polypropylene (PP). The organic solvent includes at least one of, but is not limited to, ethylene carbonate, propylene carbonate, butylene carbonate, pentylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and ethyl methyl carbonate. The polymer compound in the lithium battery recycling rough material is usually the main component of the binder and the separator; the organic solvent in the lithium battery recycling rough material is usually the main component of the electrolyte.

[0090] The preparation method provided by the present invention combines photocatalytic oxidation and heat treatment to treat lithium battery recycling materials, and controls the cooling stage of the materials after heat treatment, greatly reducing energy consumption and improving efficiency, and obtaining lithium battery recycling material powder with a lower W DOC and suitable BET.

[0091] The present invention combines photocatalytic oxidation and heat treatment to treat lithium battery recycling rough materials, aiming to remove the organic matter therein under relatively mild and economical conditions, and reduce the W DOC .

[0092] In the photocatalytic oxidation method of the present invention, ultraviolet light is used to irradiate a photocatalyst (such as titanium dioxide, zinc oxide, etc.). After the photocatalyst absorbs photons, electrons in the valence band jump to the conduction band to generate electron-hole pairs. The excited electrons reduce the oxygen adsorbed on the surface of the photocatalyst to generate superoxide anion radicals (·O2 - ), and the remaining holes can oxidize water adsorbed on the surface of the photocatalyst to generate hydroxyl radicals (·OH); the generated radicals can react with the organic matter adsorbed on the surface of the photocatalyst, oxidize and break its chemical bond to degrade it; during the process of generating radicals, the excited electrons in the photocatalyst return to the valence band. Compared with the method of using Fenton oxidation to degrade organic matter and recycle waste batteries, the ultraviolet photocatalytic oxidation degradation method of the present invention does not require the input of chemicals, nor does it require additional post-treatment, and the reaction conditions are mild, which can greatly reduce costs.

[0093] However, due to the limited degradation ability of the oxidation method for organic matter, it can only degrade the polymer chain segments into fragments. Therefore, further heat treatment is required to completely decompose the organic matter; heat treatment after oxidation greatly improves the heat treatment efficiency, and the heat treatment temperature can be reduced and the time can be shortened.

[0094] The present invention performs flash drying treatment on the optical treatment intermediate. The organic matter in the lithium battery recycling crude material, especially the binder, degrades after optical treatment and loses most of its adhesiveness. By using the high-speed hot air flow (hot air) during flash evaporation to convectively contact the material and disperse it, the organic matter is exposed on the particle surface, which is beneficial to completely eliminate it in the subsequent heat treatment stage. At the same time, by using the high-speed hot air flow (hot air) to contact the material, the moisture or solvent in the material is quickly evaporated, thereby achieving rapid drying. After drying, heat treatment is carried out to avoid violent expansion or bursting caused by the rapid evaporation of water at high temperature, thus avoiding an increase in specific surface area.

[0095] Photocatalytic oxidation treatment refers to irradiating the lithium battery recycling crude material with ultraviolet light in an oxygen-containing or / and water-containing environment in the presence of a photocatalyst; in some embodiments, the photocatalyst includes at least one of titanium dioxide and zinc oxide.

[0096] In some embodiments, the photocatalyst is anatase titanium dioxide.

[0097] In some embodiments, the particle size of the photocatalyst is less than 500 nm and is supported on at least one of the following carriers including but not limited to: aluminum foil, ceramic, glass, silica, molecular sieve, and screen, with the aim of facilitating the separation of the optical treatment intermediate from the photocatalyst. The photocatalyst with a smaller particle size is beneficial to increasing its specific surface area and the active sites of the photooxidation reaction, thereby improving the efficiency of photocatalytic oxidation treatment. Since the photocatalyst is a powder material with a small particle size, to facilitate its separation from the optical treatment intermediate and for the reuse of the photocatalyst, the photocatalyst is supported on a carrier. The present invention does not limit the carrier and the loading method of the photocatalyst. For example, the carrier loaded with the photocatalyst can be in the form of a film, sheet, plate, large particle, etc.

[0098] In some embodiments, the ultraviolet light irradiation conditions include: the light wavelength is 200 - 400 nm, and the irradiation time is 5 - 15 h. The shorter the light wavelength, the greater the energy, but wavelengths below 200 nm belong to vacuum ultraviolet and cannot be used normally in an air environment. 200 - 400 nm is the common wavelength range for photochemical reactions, and 254 nm is the most commonly used wavelength in ultraviolet reaction devices. The irradiation time affects the degradation degree of organic matter. The longer the irradiation time, the higher the degradation degree.

[0099] In some embodiments, the environmental humidity during photocatalytic oxidation treatment is maintained at 60% - 100%, and the environmental oxygen content is maintained at 30 vt% or more. According to the principle, the photocatalytic oxidation treatment process needs to be carried out under oxygen-containing conditions, and the presence of water can further promote the oxidation reaction. Therefore, the higher the environmental humidity and the oxygen content, the more beneficial it is to the progress of the photocatalytic oxidation reaction.

[0100] In some embodiments, the inlet air temperature for flash drying is 200~400°C, the outlet air temperature is 100~200°C, the rotational speed is 10~30 Hz, and the feeding frequency is 10~30 Hz.

[0101] In some embodiments, the heat treatment is carried out under negative pressure, and the pressure is -0.01~-0.05 MPa; negative pressure is conducive to the gasification and overflow of organic substances and amorphous carbon, while reducing the pore structure.

[0102] In some embodiments, the temperature of the heat treatment is 350°C~500°C, and the time is 0.5~1.5 h.

[0103] Controlling the conditions of the heat treatment, including furnace pressure, oxygen content, temperature, and time, can achieve the control of the BET specific surface area of the lithium battery recycling material powder and obtain a powder with an appropriate BET range.

[0104] In some embodiments, the cooling rate is 1~6°C / min; controlling a smaller cooling rate can avoid the accumulation of internal stress in the powder particles, facilitate the stable shrinkage of the pore diameter, thereby avoiding lattice defects and particle cracking, and effectively controlling the BET of the lithium battery recycling material powder.

[0105] Performing heat treatment on the material under a negative pressure environment is conducive to the gasification and overflow of organic substances and reduces the pore structure of the material after heat treatment. Further controlling the cooling rate of the material after heat treatment to cool it at a slower rate can, on the one hand, prevent the lithium battery recycling material powder from recombining with volatile substances in the environment to form a pollution carbon source; on the other hand, it can prevent lattice defects from occurring in the cathode active material in the lithium battery recycling material powder, which affects regeneration; furthermore, a slower cooling rate can avoid cracking of the powder due to rapid cooling, thereby increasing the porosity. A slower cooling rate is conducive to controlling the specific surface area. It is further required to cool the temperature below 20°C at this cooling rate, which is conducive to the stability and slow shrinkage of the pores of the powder material particles.

[0106] In some embodiments, the particle size of the lithium battery recycling coarse material is less than 1 cm.

[0107] In some embodiments, the lithium battery recycling coarse material is obtained by mechanically crushing battery waste through disassembly, stamping, grinding, shearing, etc.

[0108] In some embodiments, the battery waste includes but is not limited to used batteries, used battery cells, used battery wound cores, pole piece waste, unqualified batteries on the production line, etc.

[0109] In some embodiments, the light parts in the battery waste, such as plastics, aluminum foils, copper foils, etc., are removed by means such as air separation, screening, density separation, optical separation, etc.

[0110] In some embodiments, the larger parts in battery waste, such as the casing, wires, and sealing plates, can be separated by manual or automatic sorting. For example, magnetic components can be separated by a magnetic separator, and non-magnetic metals can be separated by an eddy current separator.

[0111] The present invention provides the application of the lithium battery recycling material powder in any of the above embodiments.

[0112] The lithium battery recycling material powder is applied to hydrometallurgy, and the hydrometallurgy steps include: dispersing the lithium battery recycling material powder in an acid solution to obtain a post-acid leaching solution containing metal ions.

[0113] In some embodiments, the post-acid leaching solution is subjected to steps including but not limited to impurity removal, extraction, precipitation, and drying, etc., to obtain a product enriched with valuable metal elements, and the valuable metal elements include at least one of nickel, cobalt, manganese, lithium, and iron.

[0114] In some embodiments, the post-acid leaching solution is subjected to steps including but not limited to impurity removal, extraction, etc., to obtain an aqueous solution enriched with metal salts; the metal salts include at least one of nickel salt, cobalt salt, manganese salt, and lithium salt.

[0115] In some embodiments, the post-acid leaching solution is subjected to steps including but not limited to impurity removal, precipitation, carbonization, and drying, etc., to obtain lithium carbonate.

[0116] The lithium battery recycling material powder is applied to the regeneration of the cathode material, and the steps include: enriching the cathode material in the lithium battery recycling material powder by a flotation separation method, and calcining the cathode material with lithium to obtain a regenerated cathode material.

[0117] The lithium battery recycling material powder is applied to the recycling of graphite, and the steps include: enriching the graphite in the lithium battery recycling material powder by a flotation separation method, and recycling the graphite.

[0118] In some embodiments, the graphite is heat-treated to obtain a regenerated anode material.

[0119] In some embodiments, the graphite is used to prepare graphene.

[0120] The features and properties of the present invention will be further described in detail below in conjunction with embodiments.

[0121] Example 1

[0122] A lithium battery recycling material powder, the preparation method includes the following steps:

[0123] (1) Obtain the crude lithium battery recycling material: After discharging the used ternary lithium-ion aluminum shell battery, perform double-axis shear crushing and single-axis crushing successively under nitrogen protection. The obtained crushed material is dried in a nitrogen atmosphere at 140 - 150 °C for 2 h, then dispersed by a disintegrator and screened to obtain large pieces of material (protective shell) and small pieces of material. The small pieces of material are screened by a circular vibrating screen, and the undersize is the primary crude lithium battery recycling material. The large pieces of material are successively subjected to cross-flow air separation and linear screen air separation to separate the diaphragm and aluminum shell. The remaining material is subjected to single-axis crushing again and then screened by a circular vibrating screen, and the undersize is the secondary crude lithium battery recycling material. The primary and secondary crude lithium battery recycling materials are combined to obtain the crude lithium battery recycling material.

[0124] (2) Obtain the photo-treatment intermediate: Evenly distribute the crude lithium battery recycling material on the carrier rack of the photocatalytic oxidation device, and then irradiate it with ultraviolet light for 10 h.

[0125] The carrier rack is an aluminum foil with a surface active titanium dioxide coating. The active titanium dioxide is anatase titanium dioxide with a particle size less than 500 nm, and the loading amount of the active titanium dioxide on the aluminum foil is 15 ± 2 g / m 2 .

[0126] The wavelength of the ultraviolet light is 254 nm, provided by a 15 W UVC lamp tube; the distance between the light source and the carrier rack is 30 cm - 50 cm.

[0127] Control the humidity of the photocatalytic oxidation device to be 80% - 90%, and the oxygen content to be 60 vt% - 70 vt%.

[0128] (3) Obtain the dried intermediate: Feed the photo-treatment intermediate into a flash dryer for drying to obtain the dried intermediate; set the inlet air temperature of the flash dryer to 300 °C, the outlet air temperature to 150 °C, the main machine speed to 20 Hz, and the feeding frequency to 10 Hz.

[0129] (4) Obtain the heat-treatment intermediate: Place the dried intermediate in a sintering furnace for heat treatment, control the sintering temperature to be 450 °C, the heating rate to be 5 °C / min, the furnace pressure to be -0.03 MPa, and the time to be 1 h.

[0130] (5) Obtain the lithium battery recycling material powder: After the heat treatment is completed, maintain the negative pressure in the sintering furnace and set the cooling rate to 3 °C / min. Cool the material temperature to 20 °C, disperse it with a disintegrator and then screen to obtain the lithium battery recycling material powder.

[0131] Example 2

[0132] A method for preparing a lithium battery recycling material powder includes the following steps:

[0133] (1) Obtain the crude lithium - battery recycling material: Disassemble the discharged waste ternary lithium - ion aluminum - shell battery finely to obtain the battery cells; subject the battery cells to double - shaft crushing and impact crushing in sequence, and then use a linear screen for screening. The material below the screen is the crude lithium - battery recycling material.

[0134] (2) Obtain the photo - treatment intermediate: Control the humidity of the photocatalytic oxidation device to be 60% - 70% and the oxygen content to be 60vt% - 70vt%. Other conditions are the same as in Example 1.

[0135] (3) Obtain the drying intermediate: The same as in Example 1.

[0136] (4) Obtain the heat - treatment intermediate: Control the sintering temperature to be 400 °C, the heating rate to be 5 °C / min, and the furnace pressure to be - 0.05 MPa. Other conditions are the same as in Example 1.

[0137] (5) Obtain the lithium - battery recycling material powder: Maintain the negative pressure in the sintering furnace and set the cooling rate to be 1 °C / min. Other conditions are the same as in Example 1.

[0138] Example 3

[0139] A method for preparing a lithium - battery recycling material powder includes the following steps:

[0140] (1) Obtain the crude lithium - battery recycling material: The same as in Example 1.

[0141] (2) Obtain the photo - treatment intermediate: Evenly distribute the crude lithium - battery recycling material on the carrier of the photocatalytic oxidation device, and then irradiate it with ultraviolet light for 5 h.

[0142] The carrier is a glass plate with an active zinc oxide coating on its surface. The active zinc oxide is active zinc oxide with a particle size less than 500 nm, and the loading amount of active zinc oxide on the glass plate is 25 ± 2 g / m 2 .

[0143] The wavelength of the ultraviolet light is 254 nm, provided by a 15 - W UVC lamp tube; the distance between the light source and the carrier is 30 cm - 50 cm.

[0144] Control the humidity of the photocatalytic oxidation device to be 60% - 70% and the oxygen content to be 30vt% - 40vt%.

[0145] (3) Obtain the drying intermediate: Feed the photo - treatment intermediate into a flash dryer for drying to obtain the drying intermediate; set the inlet air temperature of the flash dryer to be 300 °C, the outlet air temperature to be 150 °C, the rotation speed to be 10 Hz, and the feeding frequency to be 30 Hz.

[0146] (4)Obtain the heat treatment intermediate: Place the dried intermediate in a sintering furnace for heat treatment. Control the sintering temperature at 350 °C, the heating rate at 5 °C / min, the furnace pressure at -0.01 MPa, and the time at 1 h.

[0147] (5)Obtain the lithium battery recycling material powder: Maintain the negative pressure in the sintering furnace and set the cooling rate at 6 °C / min. The other conditions are the same as in Example 1.

[0148] Example 4

[0149] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0150] (1)Obtain the lithium battery recycling crude material: Subject the discharged waste ternary lithium-ion soft-pack battery to biaxial crushing and reamer crushing in sequence under nitrogen protection. The obtained crushed material is dried in a nitrogen atmosphere at 140 - 150 °C for 2 h, and then pneumatically conveyed to a vibrating screen for screening. The material passing through the screen is the primary lithium battery recycling crude material; further, the oversize material is subjected to magnetic separation to obtain the secondary lithium battery recycling crude material. The primary and secondary lithium battery recycling crude materials are combined to obtain the lithium battery recycling crude material.

[0151] (2)Obtain the light treatment intermediate: Irradiate it with ultraviolet light for 15 h. The other conditions are the same as in Example 1.

[0152] (3)Obtain the dried intermediate: The same as in Example 1.

[0153] (4)Obtain the heat treatment intermediate: Control the sintering temperature at 400 °C and the furnace pressure at -0.01 MPa. The other conditions are the same as in Example 1.

[0154] (5)Obtain the lithium battery recycling material powder: Maintain the negative pressure in the sintering furnace and set the cooling rate at 6 °C / min. The other conditions are the same as in Example 1.

[0155] Example 5

[0156] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0157] (1)Obtain the lithium battery recycling crude material: The process is the same as in Example 2, but different waste ternary lithium-ion aluminum shell batteries are used.

[0158] (2)Obtain the light treatment intermediate: Irradiate it with ultraviolet light for 8 h. The other conditions are the same as in Example 1.

[0159] (3)Obtain the dried intermediate: Feed the light treatment intermediate into a flash dryer for drying to obtain the dried intermediate; Set the inlet air temperature of the flash dryer at 300 °C, the outlet air temperature at 100 °C, the rotation speed at 30 Hz, and the feeding frequency at 30 Hz.

[0160] (4) Obtain the heat treatment intermediate: Control the sintering temperature at 350 °C and the furnace pressure at -0.03 MPa, and the others are the same as in Example 1.

[0161] (5) Obtain the lithium battery recycling material powder: Maintain the negative pressure in the sintering furnace and set the cooling rate at 6 °C / min, and the others are the same as in Example 1.

[0162] Example 6

[0163] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0164] (1) Obtain the lithium battery recycling rough material: The discharged waste ternary lithium-ion aluminum shell battery is successively subjected to biaxial shear crushing and uniaxial crushing under nitrogen protection. The obtained crushed material is dried in a nitrogen atmosphere at 140-150 °C for 2 h, then dispersed by a disperser, and then screened to obtain large pieces of material (protective shell) and small pieces of material; The small pieces of material are screened by a circular vibrating screen, and the undersize is the lithium battery recycling rough material.

[0165] (2) Obtain the light treatment intermediate: The lithium battery recycling rough material is evenly distributed on the carrier of the photocatalytic oxidation device, and then irradiated with ultraviolet light for 12 h.

[0166] The carrier is a glass plate with an active zinc oxide coating on the surface. The active zinc oxide is active zinc oxide with a particle size below 500 nm, and the loading amount of the active zinc oxide on the glass plate is 25 ± 2 g / m 2 .

[0167] The wavelength of the ultraviolet light is 254 nm, provided by a 15 W UVC lamp tube; the distance between the light source and the carrier is 30 cm to 50 cm.

[0168] Control the humidity of the photocatalytic oxidation device at 80% - 90% and the oxygen content at 60 vt% - 70 vt%.

[0169] (3) Obtain the drying intermediate: The light treatment intermediate is put into a flash dryer for drying to obtain the drying intermediate; Set the inlet air temperature of the flash dryer at 400 °C, the outlet air temperature at 200 °C, the rotation speed at 10 Hz, and the feeding frequency at 20 Hz.

[0170] (4) Obtain the heat treatment intermediate: The drying intermediate is placed in a sintering furnace for heat treatment, control the sintering temperature at 500 °C, the heating rate at 5 °C / min, the furnace pressure at -0.02 MPa, and the time at 1 h.

[0171] (5) Obtain the lithium battery recycling material powder: The same as in Example 1.

[0172] Example 7

[0173] A lithium battery recycling material powder, and the preparation method includes the following steps:

[0174] (1) Obtaining lithium battery recycling rough material: After discharging the used lithium iron phosphate batteries, perform secondary crushing under nitrogen protection (the first stage is a double-shaft shear crusher and the second stage is a single-shaft shear crusher). The obtained crushed material is dried in a nitrogen atmosphere at 140 - 150 °C for 2 h, then dispersed by a disintegrator, and then screened to obtain large pieces of material (the protective shell) and small pieces of material; the small pieces of material are screened by a circular vibrating screen, and the undersize is the lithium battery recycling rough material.

[0175] (2) Obtaining the photo-treatment intermediate: Evenly distribute the lithium battery recycling rough material on the carrier of the photocatalytic oxidation device, and then irradiate it with ultraviolet light for 12 h.

[0176] The carrier is a glass plate with an active zinc oxide coating on the surface. The active zinc oxide is active zinc oxide with a particle size lower than 500 nm, and the loading amount of the active zinc oxide on the glass plate is 25 ± 2 g / m 2 .

[0177] The wavelength of the ultraviolet light is 254 nm, provided by a 15 W UVC lamp tube; the distance between the light source and the carrier is 30 cm - 50 cm.

[0178] Control the humidity of the photocatalytic oxidation device to be 80% - 90%, and the oxygen content to be 60 vt% - 70 vt%.

[0179] (3) Obtaining the dried intermediate: Put the photo-treatment intermediate into a flash dryer for drying to obtain the dried intermediate; set the inlet air temperature of the flash dryer to 200 °C, the outlet air temperature to 100 °C, the rotation speed to 20 Hz, and the feeding frequency to 10 Hz.

[0180] (4) Obtaining the heat-treatment intermediate: Place the dried intermediate in a sintering furnace for heat treatment, control the sintering temperature to be 500 °C, the heating rate to be 5 °C / min, the furnace pressure to be -0.05 MPa, and the time to be 0.5 h.

[0181] (5) Obtaining the lithium battery recycling material powder: After the heat treatment is completed, maintain the negative pressure in the sintering furnace and set the cooling rate to 4 °C / min. Cool the material temperature to 20 °C, disperse it with a disintegrator, and then screen to obtain the lithium battery recycling material powder.

[0182] Example 8

[0183] A lithium battery recycling material powder, and the preparation method includes the following steps:

[0184] (1) Obtaining lithium battery recycling rough material: The same as in Example 7.

[0185] (2) Obtain the photo-treated intermediate: Evenly distribute the crude lithium battery recycling material on the carrier of the photocatalytic oxidation device, and then irradiate it with ultraviolet light for 10 h.

[0186] The carrier is an aluminum foil with a surface active titanium dioxide coating. The active titanium dioxide is anatase titanium dioxide with a particle size less than 500 nm, and the loading of the active titanium dioxide on the aluminum foil is 15 ± 2 g / m 2 .

[0187] The wavelength of the ultraviolet light is 254 nm, provided by a 15 W UVC lamp tube; the distance between the light source and the carrier is 30 cm to 50 cm.

[0188] Control the humidity of the photocatalytic oxidation device to be 60% - 70% and the oxygen content to be 30 vt% - 40 vt%.

[0189] (3) Obtain the dried intermediate: The same as in Example 7.

[0190] (4) Obtain the heat-treated intermediate: Control the sintering temperature to be 450 °C and the time to be 1 h, and the others are the same as in Example 6.

[0191] (5) Obtain the lithium battery recycling material powder: The same as in Example 7.

[0192] Example 9

[0193] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0194] (1) Obtain the crude lithium battery recycling material: The same as in Example 7.

[0195] (2) Obtain the photo-treated intermediate: Evenly distribute the crude lithium battery recycling material on the carrier of the photocatalytic oxidation device, and then irradiate it with ultraviolet light for 15 h.

[0196] The carrier is an aluminum foil with a surface active titanium dioxide coating. The active titanium dioxide is anatase titanium dioxide with a particle size less than 500 nm, and the loading of the active titanium dioxide on the aluminum foil is 15 ± 2 g / m 2 .

[0197] The wavelength of the ultraviolet light is 254 nm, provided by a 15 W UVC lamp tube; the distance between the light source and the carrier is 30 cm to 50 cm.

[0198] Control the humidity of the photocatalytic oxidation device to be 60% - 70% and the oxygen content to be 60 vt% - 70 vt%.

[0199] (3) Obtain the dried intermediate: The same as in Example 7.

[0200] (4)Obtain the heat treatment intermediate: Control the sintering temperature at 450 °C, the furnace pressure at -0.01 MPa, and the time at 1.5 h. The other conditions are the same as those in Example 7.

[0201] (5)Obtain the lithium battery recycling material powder: The same as in Example 7.

[0202] Example 10

[0203] The difference from Example 1 is that the irradiation time in step (2) is 15 h.

[0204] Example 11

[0205] The difference from Example 1 is that the irradiation time in step (2) is 5 h.

[0206] Example 12

[0207] The difference from Example 1 is that the furnace pressure in step (4) is -0.01 MPa.

[0208] Example 13

[0209] The difference from Example 1 is that the furnace pressure in step (4) is -0.05 MPa.

[0210] Example 14

[0211] The difference from Example 1 is that the cooling rate in step (5) is 1 °C / min.

[0212] Example 15

[0213] The difference from Example 1 is that the cooling rate in step (5) is 6 °C / min.

[0214] Example 16

[0215] The difference from Example 1 is that step (3) is not carried out, that is, the photo-treatment intermediate is directly subjected to heat treatment.

[0216] Example 17

[0217] The difference from Example 1 is that step (2) is not carried out, that is, the lithium battery recycling crude material obtained in step (1) is directly subjected to step (3).

[0218] Example 18

[0219] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0220] (1)Obtain the lithium battery recycling crude material: The used ternary lithium-ion aluminum shell battery after discharge is finely disassembled to obtain the positive electrode plate. The positive electrode plate is crushed, classified, and then sieved to obtain the lithium battery recycling crude material.

[0221] Steps (2) to (5) are the same as those in Example 1.

[0222] Example 19

[0223] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0224] (1) Obtain the lithium battery recycling crude material: The discharged waste lithium iron phosphate aluminum shell battery is finely disassembled to obtain the positive electrode plate, the positive electrode plate is crushed and classified, and then sieved to obtain the lithium battery recycling crude material.

[0225] (2) to (3) are the same as those in Example 7.

[0226] (4) Obtain the heat treatment intermediate: Place the dried intermediate in a sintering furnace for heat treatment, control the sintering temperature at 700 °C, the heating rate at 5 °C / min, the furnace pressure at 0.02 MPa, and the time at 1.5 h.

[0227] (5) is the same as that in Example 7.

[0228] Example 20

[0229] A lithium battery recycling material powder, the preparation method comprising the following steps:

[0230] (1) to (2) are the same as those in Example 7.

[0231] (3) Obtain the ball milling intermediate: Put the light treatment intermediate into a ball mill and ball mill for 1 h to obtain the ball milling intermediate.

[0232] (4) Obtain the heat treatment intermediate: Place the ball milling intermediate in a sintering furnace for heat treatment, control the sintering temperature at 500 °C, the heating rate at 5 °C / min, the furnace pressure at -0.05 MPa, and the time at 0.5 h.

[0233] (5) Obtain the lithium battery recycling material powder: After the heat treatment is completed, maintain the negative pressure in the sintering furnace and set the cooling rate at 10 °C / min, lower the material temperature to 20 °C, disperse with a disperser, and sieve to obtain the lithium battery recycling material powder.

[0234] Comparative Example 1

[0235] The difference from Example 1 is that the heat treatment temperature in step (4) is 900 °C and the furnace pressure is -0.07 MPa.

[0236] Comparative Example 2

[0237] The difference from Example 1 is that the heat treatment in step (4) is carried out under normal pressure and the heat treatment temperature is 300 °C.

[0238] Comparative Example 3

[0239] It is different from Example 1 in that the heat treatment intermediate in step (4) is exposed to air at room temperature (25°C) for natural cooling.

[0240] Raw material description:

[0241] The battery waste used to obtain the crude lithium battery recycling material is not necessarily the same, and the differences include battery cells, the types of cathode materials in the cathode plates, the ratio of cathode materials to anode materials, etc.

[0242] The raw materials of the lithium iron phosphate waste batteries used in Examples 7 to 9 are the same, and the raw materials of the ternary waste batteries used in Examples 10 to 15 and Comparative Examples 1 to 3 are the same as those in Example 1.

[0243] Photocatalytic oxidation treatment description:

[0244] The present invention does not limit the preparation method of the carrier rack of the photocatalytic oxidation device. Any method of loading titanium dioxide or zinc oxide with photocatalytic oxidation activity on the carrier, which can achieve the purpose of easy separation of the photocatalytic treatment intermediate from the carrier rack and the recyclability of the carrier rack, can achieve the purpose of the present invention.

[0245] The preparation method of the carrier rack with zinc oxide loaded on the glass plate includes but is not limited to: weighing soluble zinc salt and dissolving it in absolute ethanol, adding a complexing agent (diethanolamine, citric acid, ethanolamine, etc.), stirring to obtain a sol, aging, and then using the dip-coating method to load the sol on the glass sheet, and finally sintering at 450 - 600°C for 30 - 60 min to obtain the carrier rack.

[0246] Taking Example 1 as an example, the preparation method of the carrier rack of the photocatalytic oxidation device includes: weighing tetrabutyl titanate and dissolving it in absolute ethanol, adding diethanolamine and stirring for 2 h, then adding 20 wt% acetylacetone aqueous solution, and continuing to stir for 1 h to obtain titanium dioxide sol. Using the dip-coating method to load the titanium dioxide sol on an aluminum foil with a thickness of 0.2 mm, and finally sintering at 500°C to obtain the carrier rack, controlling the pulling speed, number of times, and concentration of the titanium dioxide sol, and controlling the loading capacity of the carrier rack.

[0247] Performance test method:

[0248] Test Example 1: W DOC The test includes the following steps:

[0249] ① Weigh 100.0 ± 0.01 g of the sample to be tested and place it in a 500 mL extraction bottle. Measure 300 mL (V0) of aqueous solution with a measuring cylinder and add it to the extraction bottle. Tighten the inner lid, screw the bottle cap tightly, and then vertically fix it on a water bath constant temperature oscillator;

[0250] ②Set the water temperature of the water bath thermostatic oscillator to 25°C, the oscillation frequency to 110 times / min, the amplitude to 20 mm, start the instrument, and oscillate for 60 min;

[0251] ③After the oscillation is completed, remove the extraction bottle, shake the sample to be tested well, filter it with a slow quantitative filter paper, and use the obtained filtrate for testing W DOC ;

[0252] ④Transfer a certain volume (V1) of the filtrate into a 100 mL volumetric flask, acidify it to pH ≤ 2 and make up to the mark to obtain a diluted solution with a volume of V2; after removing inorganic carbon by aeration, introduce it into the high-temperature oxidation furnace of the TOC analyzer to test the concentration C.

[0253] W DOC = ;

[0254] In the formula, C1 is the concentration measured by the TOC analyzer of the sample to be tested, mg / L; C0 is the sample concentration measured by the TOC analyzer of the blank sample, mg / L; V2 is the fixed volume of the diluted solution, mL; V1 is the volume of the filtrate transferred in step ④, mL; V0 is the volume of the initially added aqueous solution, L; m is the mass of the sample to be tested, g. The blank sample refers to the test without adding the sample to be tested in step ①.

[0255] The aqueous solution in step ① is selected from one of pH = 2, pH = 7, and pH = 10. The aqueous solution with pH = 2 is prepared by dissolving 98% sulfuric acid in pure water, the aqueous solution with pH = 10 is prepared by dissolving sodium hydroxide in pure water, and the aqueous solution with pH = 7 is pure water.

[0256] Test Example 2: The specific surface area BET is tested according to GB / T 19587-2004.

[0257] Test Example 3: According to YS / T1342.1-2019, YS / T1342.2-2019, YS / T1342.3-2019, YS / T1342.4-2019, YS / T 1028.1-2015, test the mass percentage content of metal elements Ni, Co, Mn, Li, and Fe in the lithium battery recycling material powder.

[0258] Test Example 4: Test for metal leaching efficiency, including the following steps:

[0259] Put the lithium battery recycling material powder to be tested into the acid leaching solution (sulfuric acid solution with a hydrogen peroxide volume concentration of 20% and pH = 0.5 - 1) according to a solid-liquid ratio of 1 g:4 g, stir at 80°C for 6 h, perform solid-liquid separation to obtain the post-acid leaching solution, measure the metal concentration in the post-acid leaching solution by ICP-OES, and calculate the metal leaching rate.

[0260] Metal leaching rate = × 100%;

[0261] In the formula, the metal leaching rate is the ratio of the total mass of metal elements (including at least one of Ni, Co, Mn, Fe, and Li) in the leachate after leaching to the total mass of metal elements in the lithium battery recycling material powder; 、 are the concentrations of Ni, Co, Mn, Li, and Fe in the acid leachate, respectively, in g / L; V is the volume of the acid leachate, in L; is the feeding amount of the lithium battery recycling material powder, in g; 、 are the mass percentages of Ni, Co, Mn, Li, and Fe in the lithium battery recycling material powder, respectively, in %.

[0262] The chemical reactions occurring during the acid leaching process are as follows:

[0263] 2LiFePO4 + H2SO4 + H2O2 → Li2SO4 + 2FePO4↓ + 2H2O;

[0264] 2Li(Ni x Co y Mn 1-x-y )O2 + 3H2SO4 + 3H2O2 → Li2SO4 + 2xNiSO4 + 2yCoSO4 + 2(1 - x - y)MnSO4 + 6H2O + 2O2↑;

[0265] 2Li(Co / Mn / Ni)O2 + 3H2SO4 + H2O2 → Li2SO4 + 2(Co / Mn / Ni)SO4 + 4H2O + O2↑.

[0266] Test Example 5: Flotation separation efficiency test, including the following steps:

[0267] In an XFG hanging trough flotation machine, mix the lithium battery recycling material powder and water to adjust the pulp, and add NaOH to adjust the pH to 9.5 - 10 to obtain a first pulp with a pulp concentration of 40 g / L; add the collector n - dodecane at 250 g / L to the first pulp and adjust the pulp for 3 min, then add the frother methyl isobutyl carbinol MIBC at 180 g / L and continue to adjust the pulp for 1 min. Open the gas valve to control the air inflow rate to 0.8 L / min and the stirring speed to 1800 r / min. After one rough selection and two scavenging selections, obtain the pulp underflow and foam products (including rough selection foam and scavenging selection foam); solid - liquid separate and dry the pulp underflow to obtain the metal recovery powder enriched with the cathode material; solid - liquid separate and dry the foam products to obtain the graphite recovery powder enriched with graphite.

[0268] Calculate the metal recovery rate and separation precision through the following formula to evaluate the flotation separation efficiency:

[0269] Metal recovery rate = × 100%;

[0270] Separation precision = × 100%;

[0271] Wherein, and are respectively the input amount of lithium battery recycling material powder, the yields of metal recycling powder and graphite recycling powder, are respectively the total content percentages of metal elements in lithium battery recycling material powder, metal recycling powder and graphite recycling powder, and the metal elements include at least one of Ni, Co, Mn, Fe and Li.

[0272] Test Example 6: The particle size of the lithium battery recycling material powder was tested in accordance with GB / T 19077.1-2016.

[0273] The test results of the lithium battery recycling material powder obtained in the examples and comparative examples are shown in Tables 1, 2 and 3.

[0274] Table 1

[0275]

[0276] Table 2

[0277]

[0278] Table 3

[0279]

[0280] Based on the comprehensive analysis of Tables 1-3, the lithium battery recycling material powder provided by the examples of the present invention has better metal leaching rate and flotation separation efficiency compared with the comparative examples.

[0281] Comparing Examples 1-3, it can be seen that although the separation index S of Example 2 at different pH values all meets 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, due to the smaller BET of the lithium battery recycling material powder, the S at pH = 10 exceeds the preferred range (13 m 2 / kg ≤ S ≤ 40 m 2 / kg), resulting in a decrease in its flotation separation efficiency. The reason is that the smaller BET of Example 2 indicates that there are more aggregates in the lithium battery recycling material powder and the pores of the aggregates are less, thus leading to a decrease in the separation rate of the positive and negative electrode materials. Although the separation index S of Example 3 at different pH values all meets 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, but due to the large BET and W of the lithium - battery recycling material powder DOC being large, when pH = 2, S exceeds the preferred range (2m 2 / kg ≤ S ≤ 24m 2 / kg), ultimately leading to a decrease in its metal leaching rate. The reason is that a large BET indicates that the particle size of the lithium - battery recycling material powder is small or the porosity is high. Combining with the large W DOC , it causes the powder to tend to float on the liquid surface during the hydrometallurgical process, resulting in a decrease in leaching efficiency. The separation index of Example 1 meets the preferred range both at low pH and high pH, so it has good leaching efficiency and flotation separation efficiency.

[0282] The W of Examples 1, 2, and 4 DOC is at a similar level, but they have different BETs. It can be seen from the results that as the BET increases, the metal leaching rate of the lithium - battery recycling material powder first increases and then decreases. The reason is that an excessive BET causes the lithium - battery recycling material powder to float on the liquid surface and is difficult to be completely wetted by the acid leaching solution. A too - small BET indicates that the lithium - battery recycling material powder agglomerates severely. Both of them lead to a decrease in leaching efficiency during the hydrometallurgical process. Therefore, either an excessive or a too - small BET is not conducive to improving the metal leaching rate. As the BET increases, both the metal recovery rate and the separation accuracy of the lithium - battery recycling material powder first increase and then decrease. The reason is that an excessive BET indicates that the particle size of the powder particles is too small or the porosity is too high, resulting in a smaller density difference. The metal oxide powder is more likely to adhere to the bubbles and become bubble products, leading to a decrease in separation accuracy. A too - small BET indicates that the lithium - battery recycling material powder agglomerates severely, and the graphite powder and the metal compound powder are tightly combined and difficult to separate, resulting in a decrease in separation effect and thus a decrease in the metal recovery rate.

[0283] The BETs of Examples 3 and 4 are at a similar level, but they have different W DOC . It can be seen from the results that as W DOC increases, both the metal leaching rate and the flotation separation efficiency of the lithium - battery recycling material powder decrease. The reason is that the more residual organic matter in the lithium - battery recycling material powder, the lower the difference in water wettability between the metal compound and the graphite particles, thus reducing the flotation efficiency. On the other hand, the residual organic matter in the lithium - battery recycling material powder dissolves as a surfactant during the acid leaching process, making it difficult to eliminate the bubbles generated during the leaching process. Even the metal compound powder particles adhere to the bubble surface and cannot contact the acid leaching solution for reaction. Therefore, the larger W DOC is, the lower the metal leaching efficiency.

[0284] Comparative Example 1 has a lower BET and W compared to Example 1 DOC, and the BET is lower than the preferred range, causing the separation index S to exceed the scope of the present invention. Therefore, it has a lower metal leaching rate and flotation separation efficiency. Comparative Example 1 illustrates that controlling the process for obtaining the lithium battery recycling material powder can effectively control its BET and W DOC , thus affecting its application. The heat treatment process in Comparative Example 1 adopted a higher temperature and a lower negative pressure, resulting in a higher degree of removal of organic matter in the lithium battery recycling material powder. Due to the relatively high temperature, even grain boundary fusion occurred in the metal compound powder. Therefore, the particle size of the material powder increased, the porosity decreased, and the BET decreased.

[0285] Comparative Example 2 used low temperature (300 °C) and normal pressure for heat treatment of the dried intermediate, resulting in an increase in the residual organic matter in the lithium battery recycling material powder. The residual organic matter acts as an adhesive to bond the positive and negative electrode materials together, forming tight aggregates. Therefore, Comparative Example 2 has a lower BET and a higher W compared to Example 1 DOC , causing its separation index S to exceed the scope of the present invention. Therefore, it has a lower acid leaching rate and flotation separation efficiency.

[0286] Examples 1, 10, 11, and 17 are lithium battery recycling material powders obtained under different irradiation times. As the irradiation time increases, the BET of the lithium battery recycling material powder increases, and W DOC decreases overall. The reason is that the longer the irradiation time, the higher the degree of decomposition of organic matter, thus avoiding the bonding of residual organic matter to the lithium battery recycling material powder particles, thereby increasing the BET. Example 17 was not subjected to light treatment, so it has a smaller BET and a larger W DOC , resulting in the separation index S exceeding the preferred range of the present invention at pH = 2, thus having a lower metal leaching rate. The metal leaching rate of Example 10 is lower than that of Example 1, but the separation efficiency is higher. The reason is that the BET of Example 10 is larger, indicating that its particle size is smaller or its porosity is higher, and it tends to float on the liquid surface, thus resulting in a lower metal leaching rate. However, because the removal of organic matter is more thorough (i.e., W DOC is lower), the surface wetting difference between the metal compound powder and the graphite powder is greater, so the separation effect during flotation is better.

[0287] Examples 1, 12, and 13 are lithium battery recycling material powders obtained by heat treatment under different pressures. As the pressure decreases (the negative pressure increases), the BET gradually increases, and W DOC gradually decreases. The reason is that the negative pressure during the heat treatment process can promote the gasification of organic matter, causing the gas to escape from the pores and reducing the bonding of organic matter to the powder particles.

[0288] Examples 1, 14, and 15 are lithium battery recycling material powders obtained under different cooling rates. As the cooling rate increases, the BET of the lithium battery recycling material powder increases, and W DOC changes little. The reason is that: when the cooling rate is too high, stress residues inside the particles are caused, resulting in particle breakage. The breakage leads to an increase in the particle porosity, thus increasing the specific surface area. In Comparative Example 3, the cooling process of the heat treatment intermediate was not controlled, and the heat treatment monomer was instantly exposed to cold air. Due to stress residues, internal cracks occurred in the material, so the BET was increased; in addition, the organic substances in the environment (including air and the organic substances vaporized during the heat treatment process) were quickly condensed and adhered to the surface of the powder particles, so W DOC increases, and the separation index S at pH = 10 is greater than 40 m 2 / kg, and its metal leaching rate and flotation separation efficiency are lower than those of Example 1.

[0289] In Example 16, the optical treatment intermediate was heat-treated without flash drying, and the BET of the obtained lithium battery recycling material powder decreased slightly, and W DOC increased; the reason is that the optical treatment intermediate was not dispersed through the flash drying process, resulting in incomplete exposure of the organic substances, which is not conducive to their decomposition during the heat treatment process. Therefore, W DOC is more than that of Example 1. Since non-dispersion will cause a decrease in BET; at the same time, the optical treatment intermediate was not dried through the flash drying process, resulting in rapid evaporation of the moisture in the powder particles during heat treatment, causing violent expansion or bursting phenomena, resulting in an increase in its BET; under the two action trends, the BET of the lithium battery recycling material powder in Example 16 is slightly smaller than that of Example 1, and W DOC is larger than that of Example 1.

[0290] In Example 18, the incoming material for obtaining the lithium battery recycling crude material is the positive electrode plate. The organic matter content in the positive electrode plate is less than that of the overall aluminum shell battery. Therefore, the W DOC of the obtained lithium battery recycling material powder is smaller. Since it does not contain the negative electrode material graphite and W DOC is low, the metal leaching rate of the lithium battery recycling material powder is high, and it can be directly used for the regeneration of the positive electrode material without flotation separation. However, since the positive electrode plate needs to be finely disassembled from the battery, it is difficult to produce on a large scale industrially.

[0291] In Example 19, the positive electrode plate was also used as the object for crushing to obtain the lithium battery recycling crude material. Therefore, the W DOCLower than those in Examples 7-9. However, due to the relatively high heat treatment temperature and the process being carried out under pressure, grain boundary fusion occurs in the cathode material. As a result, the BET of the lithium battery recycling material powder obtained is lower, and thus the separation index S is lower than the preferred range when pH ≤ 3, and its metal leaching rate is lower than that in Examples 7-9.

[0292] In Example 20, the flash drying process was replaced by a ball milling process, and the cooling rate was 10 °C / min. The BET of the lithium battery recycling material powder obtained was larger than that in Examples 7-9, but the difference in W DOC was not significant. Therefore, the separation index S was larger, higher than the preferred range when pH ≤ 3. Thus, the metal leaching rate was lower than that in Examples 7-9. However, the separation index S at pH = 10 was still within the preferred range, so the decline in flotation separation efficiency was not much.

[0293] In summary, for the lithium battery recycling material powder provided by the present invention, its separation index S meets 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, and it has a good metal leaching rate and the flotation separation efficiency of the cathode and anode materials. In addition, through the preparation method provided by the present invention, lithium battery recycling material powders with a separation index S meeting 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg at different pH values can be obtained. Moreover, by adjusting the process parameters in the preparation method, the separation index S of the material can be regulated, thereby regulating the application performance of the lithium battery recycling material powder.

[0294] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A lithium battery recycling material powder, characterized in that, It includes metal compound powder, elemental carbon material, and soluble organic carbon. The metal compound powder includes at least one of the following elements: lithium, nickel, cobalt, manganese, and iron; the separation index S of the lithium battery recycling material powder satisfies 0.15 m 2 / kg ≤ S ≤ 43 m 2 / kg, where S = W DOC × BET, W DOC refers to the mass percentage of soluble organic carbon in the lithium battery recycling material powder; the soluble organic carbon refers to the organic carbon that can be dissolved or dispersed in an aqueous solution with pH = 1 to 14; BET refers to the specific surface area of the lithium battery recycling material powder, with the unit of m 2 / g; the W DOC of the lithium battery recycling material powder is less than or equal to 15‰.

2. The lithium battery recycling material powder according to claim 1, characterized in that, The lithium battery recycling material powder satisfies at least one of the following characteristics 1 to 3: Feature 1: When the pH of the aqueous solution is ≤ 3, the separation index S of the lithium battery recycling material powder satisfies 2 m 2 / kg ≤ S ≤ 24 m 2 / kg; Feature 2: When the pH of the aqueous solution is ≥ 10, the separation index S of the lithium battery recycling material powder satisfies 13 m 2 / kg ≤ S ≤ 40 m 2 / kg; Feature Three: The BET of the lithium battery recycling material powder satisfies 1 m 2 / g ≤ BET ≤ 15 m 2 / g.

3. The lithium battery recycling material powder according to claim 1 or 2, characterized in that, The mass percentage of iron element in the lithium battery recycling material powder is 10% - 30%, and the BET of the lithium battery recycling material powder is 10 - 15m 2 / g.

4. The lithium battery recycling material powder according to claim 1 or 2, characterized in that, The mass percentage of cobalt element in the lithium battery recycling material powder is 1% - 50%, and the BET of the lithium battery recycling material powder is 1 - 3 m 2 / g.

5. The lithium battery recycling material powder according to claim 4, wherein The Dv10 of the lithium battery recycling material powder is 0.1 - 1.5 μm.

6. The lithium battery recycling material powder according to claim 4, characterized in that, The Dv10 of the lithium battery recycling material powder is 0.5 - 5.2 μm.

7. The lithium battery recycling material powder according to claim 1 or 2, characterized in that, The mass percentage of lithium element in the lithium battery recycling material powder is 0 - 10%.

8. The preparation method of the lithium battery recycling material powder according to any one of claims 1 to 7, characterized in that, It includes the following steps: Provide a lithium battery recycling crude material containing a negative electrode material, a positive electrode material, and an organic substance; Perform photocatalytic oxidation treatment on the lithium battery recycling crude material to obtain a photo-treatment intermediate; Perform flash drying on the photo-treatment intermediate to obtain a dried intermediate; Perform heat treatment on the dried intermediate to obtain a heat-treatment intermediate; Cool down to below 20°C in an inert atmosphere, crush and screen to obtain the lithium battery recycling material powder.

9. Use of the lithium battery recycling material powder according to any one of claims 1 to 7, characterized in that, The lithium battery recycling material powder is applied to hydrometallurgy. The hydrometallurgy steps include: dispersing the lithium battery recycling material powder in an acid solution to obtain an acid leaching post-liquid containing metal ions.

10. Use of the lithium battery recycling material powder according to any one of claims 1 to 7, characterized in that, The lithium battery recycling material powder is applied to the regeneration of the positive electrode material. The steps include: enriching the positive electrode material in the lithium battery recycling material powder by flotation separation method, and calcining the positive electrode material with lithium to obtain a regenerated positive electrode material.

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