A waste battery material powder, a preparation method thereof and application thereof

Abstract

The application discloses a waste battery material powder and a preparation method and application thereof, and belongs to the technical field of battery recycling. The waste battery material powder comprises metal compound powder and elemental carbon material, the content percentage of carbon elements in the waste battery material powder is 10wt%-40wt%, and I D / I G ≤0.5, wherein I D , I G are the intensity of D-band characteristic peaks and G-band characteristic peaks in a Raman spectrum of the waste battery material powder respectively. The waste battery material powder has a lower I D / I G value, indicating that the waste battery material powder has a lower content of amorphous carbon and a lower oxidation degree of graphite; the waste battery material powder meeting the conditions of the content percentage of carbon elements being 10wt%-40wt% and I D / I G ≤0.5 has a good metal recovery rate in a hydrometallurgical process, and the obtained graphite residue can have good regeneration capacity.

Description

TECHNICAL FIELD

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

[0002] With the rapid development of science and technology, the market demand for new energy field, especially new energy vehicles, is continuously expanding. As the core component of new energy vehicles, lithium batteries have been widely used. However, the problem of retired battery disposal has become a bottleneck for the development of the industry. The waste battery powder recycling technology emerged as the times require, which recycles valuable metals and materials in waste batteries for recycling, realizing the green transformation of waste into treasure.

[0003] Waste battery powder is mainly derived from the disassembly, crushing and screening processes of waste lithium batteries, and mainly contains valuable metals such as lithium, cobalt, nickel and manganese, as well as non-metallic materials such as carbon powder and plastic. If waste batteries are not properly disposed of, the loss of valuable metals will result in resource waste, and carbon powder and plastic will pollute the soil and water.

[0004] Currently, the mainstream methods or research directions for recycling and reusing waste battery powder include pyrometallurgy, direct regeneration and hydrometallurgy. Among them, pyrometallurgy refers to a metallurgical method that separates metals from other impurities through high-temperature smelting and reduction reactions to obtain elemental metals. This method has low waste utilization rate, high energy consumption and high pollution, and can only obtain metal alloys. Direct regeneration refers to solving the problem of material failure on the basis of not destroying the inherent structure of the material, achieving 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 performance of the regenerated positive electrode material still cannot meet the application requirements. Hydrometallurgy refers to ionizing metal elements, and then separating and enriching metals through precipitation, electrodeposition, extraction, ion exchange and other technologies, and finally recovering the target metal in the form of its certain compound. This method can obtain relatively pure metal compounds for direct preparation of electrode materials.

[0005] Specifically, the process of hydrometallurgy includes acid leaching treatment, i.e. putting waste battery material powder into a solution containing a reducing agent (usually hydrogen peroxide) and a concentrated acid (usually sulfuric acid) to ionize valuable metals and store them in the liquid phase, and then separating the insoluble substances (called "graphite slag") through solid-liquid separation. The main component of graphite slag is carbon, including graphite and conductive agent. Due to the small particle size and large specific surface area of graphite slag, it will adsorb a certain amount of valuable metal ions (such as lithium ions, nickel ions, cobalt ions, manganese ions and iron ions), on the one hand, reducing the recovery rate of valuable metals, and on the other hand, the residual metals in graphite slag are difficult to handle, resulting in the difficulty of recycling graphite slag, which can only be discharged as solid waste.

[0006] In view of this, the present application is proposed. SUMMARY

[0007] The present application aims to provide a waste battery material powder, a preparation method thereof and an application thereof, so as to solve or improve the above technical problems.

[0008] The present application is implemented as follows:

[0009] In a first aspect, the present application provides a waste battery material powder, which comprises a metal compound powder and an elemental carbon material, the content of carbon element in the waste battery material powder is 10wt%-40wt%, and I D / I G ≤0.5, wherein I D , I G are the intensity of D-band characteristic peak and G-band characteristic peak in the Raman spectrum of the waste battery material powder, respectively, the wave number of the D-band characteristic peak is 1300cm -1 -1400cm -1 , and the wave number of the G-band characteristic peak is 1500cm -1 -1600cm -1 .

[0010] In an optional embodiment, the waste battery material powder further has at least one of the following characteristics:

[0011] Characteristic 1: the half-height width of the G-band characteristic peak is lower than 50cm -1 ;

[0012] Characteristic 2: in the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ=26°-27° is characteristic peak 1, and the interplanar spacing corresponding to the characteristic peak 1 is 0.3354nm-0.3420nm;

[0013] Characteristic 3: in the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ=26°-27° is characteristic peak 1, and the characteristic peak corresponding to 2θ=10°-12° is characteristic peak 2, and the peak intensity ratio I2 / I1 of the characteristic peak 2 and the characteristic peak 1 is 0-0.2;

[0014] Characteristic 4: the metal in the metal compound powder comprises at least one of lithium, nickel, cobalt, manganese and iron.

[0015] In an optional embodiment, the value of I D / I G is 0.19-0.48.

[0016] In an optional embodiment, I D , I G , I1 and I2 satisfy the following relationship:

[0017] In a second aspect, the present application provides a method for preparing the waste battery material powder as defined in any one of the preceding embodiments, comprising the following steps: crushing the waste battery cell to be treated, first drying, and sorting to obtain a coarse material containing positive electrode active material and negative electrode active material;

[0018] mixing the coarse material with a solvent and ball milling to obtain a wet material;

[0019] second drying the wet material, and then pyrolyzing to obtain an oxidized material;

[0020] microwaving the oxidized material to obtain the waste battery material powder.

[0021] In an optional embodiment, the first drying is performed at a temperature of 180-240℃ for 1-3h.

[0022] In an optional embodiment, the second drying is performed by fluidized bed drying at a temperature of 80-120℃ for 1-3h at an air inlet frequency of 20-40Hz.

[0023] In an optional embodiment, the mass ratio of the coarse material to the solvent is 1:0.2-1:0.4.

[0024] In an optional embodiment, the particle size of the coarse material is ≤5cm.

[0025] In an optional embodiment, the particle size of the wet material is ≤500μm.

[0026] In an optional embodiment, the pyrolysis is performed in an oxygen concentration of 10-20vol%.

[0027] In an optional embodiment, the microwaving is performed at a power of 400-800W for 10-30min.

[0028] In a third aspect, the present application provides a use of the waste battery material powder as defined in any one of the preceding embodiments, for example, the waste battery material powder is used for hydrometallurgical recovery of metal materials and graphite.

[0029] The present application has the following advantages:

[0030] The content of carbon element in the waste battery material powder provided by the present application is 10-40wt%, and the I D / I GThe waste battery material powder has a lower content of amorphous carbon and a lower oxidation degree of graphite, thereby reducing the case that the amorphous carbon carries valuable metals, so that the waste battery material powder has a good metal element recovery rate in a hydrometallurgy process, and the graphite residue obtained by hydrometallurgy has a good regeneration capacity. The preparation method of the waste battery material powder provided by the application effectively reduces the content of amorphous carbon in the waste battery material powder and the oxidation degree of graphite by combining multiple methods including wet ball milling, pyrolysis and microwave irradiation, so as to obtain the waste battery material powder meeting the above conditions. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0032] Figure 1 The Raman spectrum of the waste battery material powder of Example 1 and Comparative Example 1 after baseline deduction;

[0033] Figure 2 The XRD spectrum of the waste battery material powder of Example 1. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased on the market.

[0035] The waste battery material powder provided by the application and the preparation method and application thereof will be specifically described below.

[0036] The application provides a waste battery material powder, which comprises a metal compound powder and an elemental carbon material.

[0037] The metal in the metal compound powder includes at least one of lithium, nickel, cobalt, manganese and iron. When the waste battery material powder is a lithium iron phosphate waste battery powder, the mass percentage of iron in the waste battery material powder can be no more than 30% (such as 10%, 15%, 20%, 25% or 30%, etc.); when the waste battery material powder is a lithium nickel cobalt manganese oxide waste battery powder, the mass percentage of nickel in the waste battery material powder can be 10% to 50% (such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc.), the mass percentage of cobalt in the waste battery material powder can be no more than 30%; the mass percentage of manganese in the waste battery material powder can be no more than 30%; when the waste battery material powder is a lithium cobalt oxide waste battery powder, the mass percentage of cobalt in the waste battery material powder can be no more than 50%; when the metal compound powder of the waste battery material powder contains lithium, the mass percentage of lithium in the waste battery material powder can be no more than 10% (such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.).

[0038] The source of the elemental carbon material in the waste battery material powder includes graphite negative electrodes, conductive agents and organic matter decomposition residues. The elemental carbon is divided into graphite carbon and non-graphite carbon, and the graphite carbon mainly comes from graphite negative electrodes, and the non-graphite carbon mainly comes from conductive agents and organic matter decomposition residues.

[0039] The graphite carbon has a regular layered structure, high crystallinity, defect-free crystals, low porosity, low interlayer spacing and high hydrophobicity; the non-graphite carbon is in an amorphous state, contains crystal defects, has low crystallinity, high porosity, large interlayer spacing and high hydrophilicity. The high porosity and large interlayer spacing of the non-graphite carbon make it easy to carry valuable metal ions, thereby reducing the metal leaching rate in the hydrometallurgical process; and the metal elements remaining in the graphite slag need to be further removed before the graphite slag is regenerated, so the lower the metal leaching rate in the hydrometallurgical process, the lower the regeneration of the graphite slag and the higher the regeneration cost.

[0040] In the present application, the content percentage of carbon in the waste battery material powder is 10wt% to 40wt%, and I D / I G ≤0.5. Wherein, I D , I G are the intensities of the D band characteristic peak and the G band characteristic peak in the Raman spectrum of the waste battery material powder, the wave number of the D band characteristic peak is 1300cm -1 -1400cm -1 , and the wave number of the G band characteristic peak is 1500cm -1 -1600cm -1The waste battery material powder meeting the above conditions has a high metal leaching rate, and the graphite residue obtained after acid leaching has good regeneration.

[0041] In some optional embodiments, the content of carbon element in the waste battery material powder can be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt% or 40wt%, etc., and can also be other values or other ranges within 10wt%-40wt%, such as 11.24wt%-38.57wt%.

[0042] In some optional embodiments, I D / I G may be 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15 or 0.1, etc., and can also be other values or other ranges within ≤0.5, for example, can be 0.19-0.48. In some more typical embodiments, I D / I G is 0.28-0.43.

[0043] Based on the above, the waste battery material powder provided by the present application has a low I D / I G value, indicating that the non-graphitic carbon content is low, so that the metal ions adsorbed or carried in the hydrometallurgical process are less, thereby facilitating the improvement of the metal leaching rate in the acid leaching process, and the purity of the obtained graphite residue is high, which can reduce the process and cost of the graphite residue regeneration process. Specifically, the 1500cm -1 -1600cm -1 corresponding G band characteristic peak in the Raman spectrum represents the in-plane stretching of sp 2 hybridization of carbon atoms, reflecting the ordered structure of graphite; the 1300cm -1 -1400cm -1 corresponding D band characteristic peak represents the defects within the carbon atom lattice, reflecting the defects or disordered structure of graphite. The ratio of the intensity of the G band characteristic peak to the D band characteristic peak I D / I G can evaluate the degree of disorder of the carbon material, and the smaller the I D / I G value, the higher the ordered degree of the carbon material, the fewer the number of defects, that is, the lower the non-graphitic carbon content in the carbon material.

[0044] It should be noted that the non-graphitic carbon includes amorphous carbon and oxidized graphite, the amorphous carbon has no sharp peak observed on the XRD pattern, only a package peak, and no G band characteristic peak is observed in the Raman spectrum; the oxidized graphite is the product after the oxidation treatment of graphite, and the defects and disordered structure introduced by oxidation make the interlayer spacing of graphite increase, so the D band characteristic peak of the former is stronger than that of the graphite.

[0045] In some optional embodiments, the half-height width of the G band characteristic peak is less than 50 cm -1 , such as 23.89 cm -1 ~ 46.67 cm -1 .

[0046] It should be noted that the higher the oxidation degree of graphite, the larger the half-height width of the G band characteristic peak; the oxidation of graphite, on the one hand, will make its surface carry oxygen-containing active groups (such as -OH, -COOH, etc.), and the electrostatic adsorption force of metal ions will be enhanced; on the other hand, it will make it easy to be further oxidized and intercalated by the oxidant / acid system in the hydrometallurgical process, resulting in the increase of the interlayer spacing of graphitized carbon, and thus the metal ion intercalation carried in the graphite, reducing the recovery rate of the metal, and also increasing the recovery cost and difficulty of the graphite residue.

[0047] In the present application, the half-height width of the G band characteristic peak is less than 50 cm -1 , indicating that the oxidation degree of graphite in the waste battery material powder is low, which is beneficial to reduce the adsorption or carrying of metal ions in the hydrometallurgical process, thereby improving the metal leaching rate; on the other hand, it is beneficial to reduce the impurities in the graphite residue obtained by hydrometallurgy, and also reduce the influence of high acid and high temperature on graphite in the acid leaching process.

[0048] In some optional embodiments, in the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ = 26° ~ 27° is the characteristic peak 1, and the interplanar spacing d1 corresponding to the characteristic peak 1 is 0.3354 nm ~ 0.3420 nm, such as 0.3384 nm ~ 0.3419 nm.

[0049] The above characteristic peak 1 corresponds to the (002) crystal plane between the graphite layers, the smaller the interplanar spacing, the higher the graphitization degree of the material and the smaller the interlayer spacing, the more difficult it is for metal ions to intercalate and be carried in the graphite during the hydrometallurgical process, thereby more conducive to improving the recovery rate of the metal. The interplanar spacing of the (002) crystal plane of graphite reflects the damage degree of the graphite negative electrode in the battery use process, and during the lithium ion deintercalation cycle, even when the electrolyte is co-intercalated, it will make the interlayer spacing of the graphite negative electrode increase continuously, resulting in the increasing internal resistance until failure. The graphite in the waste battery material powder can be repaired by heat treatment and other methods to reduce the interplanar spacing.

[0050] In some optional embodiments, in the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ = 26° to 27° is characteristic peak 1, the characteristic peak corresponding to 2θ = 10° to 12° is characteristic peak 2, and the peak intensity ratio I2 / I1 of characteristic peak 2 and characteristic peak 1 is 0 to 0.2, such as 0 to 0.19.

[0051] In other words, the XRD pattern of waste battery material powder may or may not contain characteristic peak 2. When the XRD pattern of waste battery material powder does not contain characteristic peak 2, the value of I2 / I1 is 0; when the XRD pattern of waste battery material powder contains both characteristic peak 1 and characteristic peak 2, the value of I2 / I1 is >0 and ≤0.2.

[0052] The aforementioned characteristic peak 2 corresponds to the (001) crystal plane of graphite oxide. The peak intensity of this characteristic peak can reflect the degree of graphite oxidation; the higher the degree of graphite oxidation, the larger I2. Graphite oxidation increases the interlayer spacing of its crystals, which is detrimental to improving the metal leaching rate in hydrometallurgy and the regeneration of graphite slag.

[0053] In some alternative implementations, I D I G I1 and I2 satisfy the following relationship: For example, The value can be 0.19, 0.25, 0.3, 0.35 or 0.4, or other values ​​in the range of 0.19 to 0.4 or other ranges, such as 0.19 to 0.36.

[0054] satisfy The waste battery material powder exhibits a higher metal leaching rate in hydrometallurgy, and the resulting graphite slag has superior recyclability. As mentioned earlier, It reflects the degree of structural order of carbon elemental in waste battery material powder, that is, it comprehensively reflects the ratio of non-graphite carbon (including amorphous carbon and graphite oxide) to graphite carbon. This reflects the degree of graphite oxidation in the waste battery material powder. and The difference reflects the contribution of amorphous carbon to the overall degree of disorder. Compared to graphite oxide, amorphous carbon has a stronger adsorption and carrying capacity for metal ions. This is because the former achieves metal ion adsorption and carrying based on electrostatic adsorption of surface groups and intercalation between carbon layers, while the latter achieves adsorption and loading of metal ions based on its rich porous structure. Therefore, further control of waste battery material powder is needed to achieve lower... This value is beneficial for improving the metal leaching rate. Furthermore, amorphous carbon is difficult to convert into graphite during graphite regeneration; therefore, the content of amorphous carbon ultimately affects the content of amorphous carbon in the regenerated graphite, thus affecting its electrochemical performance.

[0055] Accordingly, the application also provides a preparation method of the waste battery material powder, comprising the following steps: crushing the waste battery monomer to be treated, first drying, and sorting to obtain a coarse material containing positive active material and negative active material;

[0056] Mixing and ball-milling the coarse material with a solvent to obtain a wet material;

[0057] Second drying the wet material, and then pyrolyzing to obtain an oxidized material;

[0058] Microwaving the oxidized material to obtain the waste battery material powder.

[0059] In some optional embodiments, the waste battery monomer comprises at least one of various battery monomers such as square batteries, cylindrical batteries, and soft-pack batteries.

[0060] In some optional embodiments, the crushing mode can exemplarily but non-limitatively comprise at least one of jaw crushing, hammer crushing, cone crushing, impact crushing, ball milling, rod milling, roller crushing, and high-pressure roller milling, so as to realize the crushing of the battery monomer.

[0061] In some optional embodiments, the temperature of the first drying can be 180-240°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, or 240°C, or other values within the range of 180-240°C.

[0062] The time of the first drying can be 1-3h, such as 1h, 1.5h, 2h, 2.5h, or 3h, or other values within the range of 1-3h.

[0063] The sorting refers to removing or partially removing plastics, aluminum foil, copper foil, aluminum shell, steel shell, and the like by means of screening, density sorting, electric sorting, light sorting, vibration sorting, and the like, to obtain the coarse material rich in positive active material and negative active material. The negative active material comprises graphite; and the positive active material comprises at least one of lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel-cobalt-manganese, lithium nickel-cobalt-aluminum, and lithium iron phosphate.

[0064] In some optional embodiments, the particle size of the coarse material is ≤5cm.

[0065] In some optional embodiments, the solvent used for ball milling can exemplarily but non-limitingly include at least one of N-methyl pyrrolidone (NMP) and N,N-dimethylformamide (DMF). The mass ratio of the crude material to the solvent can be 1:0.2 to 1:0.4, such as 1:0.2, 1:0.25, 1:0.3, 1:0.35 or 1:0.4, etc., and can also be other values within the range of 1:0.2 to 1:0.4.

[0066] The above solvent can better dissolve the binder. The mixing and ball milling of the above solvent and the crude material can accelerate the falling off of the binder, so that the active material and the current collector and different active material particles can be quickly separated, and the binder can be quickly decomposed during subsequent pyrolysis. In addition, through ball milling, the particle size of the powder can be reduced, the specific surface area of the powder can be increased, and thus the heating area of the powder during pyrolysis can be increased, the pyrolysis effect can be improved, and the leaching efficiency of the positive active material in the hydrometallurgy process can be improved. Compared with soaking the waste battery material in an organic solvent, the crude material is mixed with the solvent for ball milling in a mass ratio greater than 1, which not only can reduce the amount of organic reagent used, but also can reduce the pressure of waste liquid treatment.

[0067] In some optional embodiments, the particle size of the wet material is ≤500 μm.

[0068] In some optional embodiments, the second drying is performed by using a fluidized bed drying method.

[0069] By placing the wet material after ball milling on the fluidized bed for drying, on the one hand, the particles can be prevented from being re-bonded after solvent evaporation, and on the other hand, the organic matter and amorphous carbon can be exposed on the surface of the particles, so that the specific surface area can be increased, thereby facilitating subsequent pyrolysis and gasification.

[0070] Exemplarily, the temperature of the second drying can be 80℃-120℃, such as 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃ or 120℃, etc., and can also be other values within the range of 80℃-120℃.

[0071] The time of the second drying can be 1h-3h, such as 1h, 1.5h, 2h, 2.5h or 3h, etc., and can also be other values within the range of 1h-3h.

[0072] The air inlet frequency of the second drying can be 20Hz-40Hz, such as 20Hz, 25Hz, 30Hz, 35Hz or 40Hz, etc., and can also be other values within the range of 20Hz-40Hz.

[0073] In the present application, the pyrolysis is carried out under a limited oxygen environment. In some alternative embodiments, the pyrolysis is carried out under the condition that the oxygen concentration is 10vt% to 20vt%. The oxygen concentration can be 10vt%, 15vt% or 20vt%, or other values within the range of 10vt% to 20vt%.

[0074] In the present application, the pyrolysis of the second dried material is carried out under a limited oxygen condition, and the oxygen concentration is controlled to be 10vt% to 20vt%, which is beneficial to the rapid gasification and decomposition of amorphous carbon, and at the same time avoids the excessive oxidation of graphite.

[0075] In some alternative embodiments, the power of the microwave treatment can be 400W to 800W, such as 400W, 450W, 500W, 550W, 600W, 650W, 700W, 750W or 800W, or other values within the range of 400W to 800W.

[0076] The time of the microwave treatment can be 10min to 30min, such as 10min, 15min, 20min, 25min or 30min, or other values within the range of 10min to 30min.

[0077] The above microwave treatment process is carried out under an inert atmosphere.

[0078] In the present application, the microwave treatment of the oxidized material is carried out under an inert atmosphere, which can produce a local overheating effect in the material, thereby achieving the effect of repairing the graphite structure and reducing the degree of oxidation.

[0079] In addition, the present application also provides an application of the above-mentioned waste battery material powder, for example, the waste battery material powder can be used for wet metallurgical recovery of metal materials and graphite.

[0080] The features and performance of the present application are further described in detail below in combination with examples.

[0081] Example 1

[0082] The present example provides a waste battery material powder, and the preparation method thereof comprises the following steps:

[0083] S1: The discharged waste ternary lithium ion aluminum shell battery is sequentially subjected to double-axis shearing crushing and single-axis crushing under nitrogen protection, the crushed material is subjected to first drying at 190℃ to 200℃ and under a nitrogen atmosphere for 2h, then is scattered by a scattering machine and is sieved to obtain large block material (protective shell) and small block material; the small block material is sieved by a circular vibrating screen, and the undersize material obtained is coarse material, and the particle size of the coarse material is controlled to be ≤3cm.

[0084] S2: The coarse material and solvent (DMF) were mixed in a mass ratio of 1:0.3, and then ball milled in a ball mill to a particle size of ≤500 μm to obtain a wet material;

[0085] S3: The wet material was placed in a fluidized bed for second drying, the temperature of the second drying was 100℃, the air inlet frequency was 30Hz, and the drying time was 2h to obtain a dry fine material; then the dry fine material was placed in a rotary kiln, and pyrolysis was performed under limited oxygen (oxygen concentration of 10vt%) and at 500℃ for 1.5h to obtain an oxidized material;

[0086] S4: The oxidized material was transferred to a microwave heating device, and microwave treatment was performed under a nitrogen atmosphere at a power of 600W for 30min to obtain a waste battery material powder.

[0087] Example 2

[0088] The difference between this example and Example 1 is that in S1, the battery monomer is a ternary soft package; in S2, the mass ratio of the coarse material to the solvent is 1:0.2; in S3, the temperature of the second drying is 80℃, the air inlet frequency is 20Hz, and the second drying time is 1h; and the pyrolysis is performed in an environment with an oxygen concentration of 5vt%, and the pyrolysis time is 2h.

[0089] Example 3

[0090] The difference between this example and Example 1 is that in S2, the mass ratio of the coarse material to the solvent is 1:0.2; and in S3, the pyrolysis is performed in an environment with an oxygen concentration of 15vt%, and the pyrolysis time is 2h.

[0091] Example 4

[0092] The difference between this example and Example 1 is that in S2, the solvent is NMP, and the mass ratio of the coarse material to the solvent is 1:0.2; in S3, the temperature of the second drying is 120℃, the pyrolysis is performed in an environment with an oxygen concentration of 20vt%, the pyrolysis temperature is 550℃, and the pyrolysis time is 2h.

[0093] Example 5

[0094] The difference between this example and Example 1 is that in S2, the mass ratio of the coarse material to the solvent is 1:0.4; in S3, the temperature of the second drying is 120℃, the air inlet frequency is 40Hz, the pyrolysis is performed in an environment with an oxygen concentration of 15vt%, and the pyrolysis time is 2h; and in S4, the microwave power is 800W.

[0095] Example 6

[0096] The difference between this embodiment and embodiment 1 is that in S2, the solvent is NMP, and the mass ratio of the crude material to the solvent is 1:0.2; in S3, the temperature of the second drying is 120 DEG C, the air inlet frequency is 20 Hz, the temperature of the second drying is 1 h, the pyrolysis temperature is 450 DEG C, and the pyrolysis time is 1.5 h; in S4, the microwave power is 800 W, and the microwave treatment time is 20 min.

[0097] Embodiment 7

[0098] The difference between this embodiment and embodiment 1 is that in S1, the battery monomer is LCR soft package, the temperature of the first drying is 230 DEG C-240 DEG C, and the particle size of the crude material is less than or equal to 5 cm; in S3, the temperature of the second drying is 120 DEG C, the air inlet frequency is 40 Hz, the time of the second drying is 3 h, the pyrolysis temperature is 550 DEG C, the pyrolysis is carried out in an environment with an oxygen concentration of 20 vol%, and the pyrolysis time is 2 h; in S4, the microwave power is 600 W.

[0099] Embodiment 8

[0100] The difference between this embodiment and embodiment 1 is that in S1, the battery monomer is LFP aluminum shell, and the temperature of the first drying is 180 DEG C-190 DEG C; in S2, the mass ratio of the crude material to the solvent is 1:0.4; in S3, the temperature of the second drying is 120 DEG C, the air inlet frequency is 40 Hz, the time of the second drying is 1 h, the pyrolysis is carried out in an environment with an oxygen concentration of 15 vol%, and the pyrolysis time is 2 h.

[0101] Embodiment 9

[0102] The difference between this embodiment and embodiment 1 is that in S1, the battery monomer is LFP aluminum shell, and the temperature of the first drying is 180 DEG C-190 DEG C; in S2, the mass ratio of the crude material to the solvent is 1:0.2; in S3, the temperature of the second drying is 80 DEG C, the air inlet frequency is 20 Hz, and the time of the second drying is 3 h; in S4, the microwave power is 700 W, and the microwave treatment time is 10 min.

[0103] Embodiment 10

[0104] The difference between this embodiment and embodiment 1 is that in S2, the mass ratio of the crude material to the solvent is 1:0.2.

[0105] Embodiment 11

[0106] The difference between this embodiment and embodiment 1 is that in S2, the mass ratio of the crude material to the solvent is 1:0.4.

[0107] Embodiment 12

[0108] The difference between this embodiment and embodiment 1 is that in S2, the mass ratio of the crude material to the solvent is 1:0.1.

[0109] Example 13

[0110] The difference between this example and Example 1 is that in S3, the pyrolysis is carried out in an environment with an oxygen concentration of 15 vt%.

[0111] Example 14

[0112] The difference between this example and Example 1 is that in S3, the pyrolysis is carried out in an environment with an oxygen concentration of 20 vt%.

[0113] Example 15

[0114] The difference between this example and Example 1 is that in S4, the microwave power is 400 W.

[0115] Example 16

[0116] The difference between this example and Example 1 is that in S4, the microwave power is 800 W.

[0117] Comparative Example 1

[0118] The difference between this comparative example and Example 1 is that in S3, the pyrolysis is carried out in an environment with an oxygen concentration of 25 vt%.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 1 is that in S3, the pyrolysis is carried out in an environment with an oxygen concentration of 0 vt%.

[0121] Comparative Example 3

[0122] The difference between this comparative example and Example 1 is that in S3, the second drying is carried out using a normal drying method, but the temperature and time of the second drying are the same as in Example 1.

[0123] Comparative Example 4

[0124] The difference between this comparative example and Example 1 is that there is no S4 step.

[0125] Application Example

[0126] Application Examples 1-20 are the hydrometallurgical applications of the waste battery material powder in Examples 1-16 and Comparative Examples 1-4, respectively.

[0127] Among them, the hydrometallurgical applications of Application Examples 1-7 and 10-20 include the following steps:

[0128] (a) The waste battery material powder is put into the acid leaching solution (20% volume concentration of hydrogen peroxide in sulfuric acid solution with pH = 0.5-1) at a solid-liquid ratio of 1 g:10 mL, stirred at 80°C for 6 h, the pH is monitored and sulfuric acid is added during the process, the pH of the acid leaching solution is controlled to be 1-1.5, and then solid-liquid separation is performed to obtain the acid leaching solution and the acid leaching residue;

[0129] (b) The acid leaching residue is put into ionized water to obtain a slurry with a solid content of 200 g / L, stirred at 60°C for 1 h, and then solid-liquid separation is performed to obtain the washing solution and the water washing residue; the washing solution is concentrated and combined with the acid leaching solution to obtain the valuable metal extraction solution;

[0130] (c) The water washing residue is washed to neutral with water and dried at 80°C to constant weight to obtain the purified graphite;

[0131] (d) The purified graphite is calcined in a high-temperature tube furnace under nitrogen protection at 1500°C for 2 h to obtain the regenerated graphite.

[0132] The hydrometallurgical application of examples 8-9 includes the following steps:

[0133] (a) The waste battery material powder is put into the acid leaching solution (sulfuric acid solution with pH = 0.5-1) at a solid-liquid ratio of 1 g:10 mL, stirred at 80°C for 6 h, and the pH of the acid leaching solution is controlled to be 1-1.5, and then solid-liquid separation is performed to obtain the acid leaching solution and the acid leaching residue;

[0134] (b) The acid leaching residue is put into ionized water to obtain a slurry with a solid content of 200 g / L, stirred at 60°C for 1 h, and then solid-liquid separation is performed to obtain the washing solution and the water washing residue; the washing solution is concentrated and combined with the acid leaching solution to obtain the valuable metal extraction solution;

[0135] (c) The water washing residue is washed to neutral with water and dried at 80°C to constant weight to obtain the purified graphite;

[0136] (d) The purified graphite is calcined in a high-temperature tube furnace under nitrogen protection at 1500°C for 2 h to obtain the regenerated graphite.

[0137] The chemical reactions involved in the acid leaching process in the above hydrometallurgical application include:

[0138] 2LiFePO4+3H2SO4→Li2SO4+2FeSO4+2H3PO4;

[0139] 2Li(Ni x Co y Mn 1-x-y )O2+3H2SO4+3H2O2→Li2SO4+2xNiSO4+2yCoSO4+2(1-x-y)MnSO4+6H2O+2O2↑;

[0140] 2Li(Co / Mn / Ni)O2+3H2SO4+H2O2→Li2SO4+2(Co / Mn / Ni)SO4+4H2O+O2↑;

[0141] 2Al+3H2SO4→Al2(SO4)3+3H2↑;

[0142] Al2O3+3H2SO4→Al2(SO4)3+3H2O;

[0143] Fe+H2SO4→FeSO4+H2↑;

[0144] Cu+H2O2+2H + →Cu 2+ +2H2O。

[0145] Test Example

[0146] (1) The performance of the waste battery material powder obtained in Examples 1-16 and Comparative Examples 1-4 was tested, and the testing method included:

[0147] ① Raman spectrum: The waste battery material powder was characterized by a German WITec alpha300R Raman spectrometer, the scanning range was 50cm -1 -4000cm -1 , the excitation wavelength was 532nm, at least 3 points of each sample were measured, the I D / I G and G band half-height width of the sample were averaged, and the average value needed to meet the dispersion coefficient (=standard deviation ÷ average value)≤0.2. The half-height width of the G band characteristic peak can be analyzed by Origin, PeakFit and other software. For example, the G band characteristic peak in Table 1 of the application was analyzed by the following method: the baseline of the Raman curve was deducted by Origin software, and then Gaussian fitting was performed to obtain the half-height width, and the fitting goodness COD was required to be above 0.9.

[0148] Figure 1 Figure is the Raman spectrum of the waste battery material powder of Example 1 and Comparative Example 1 after baseline deduction.

[0149] ② XRD: Ultima IV X-ray powder diffractometer was used to characterize the waste battery material powder, the scanning mode was continuous scanning, the scanning speed was 0.02° / s, and the scanning range was 5°-50°. The d1 and peak intensity ratio I2 / I1 were obtained by analyzing the spectrum by Jade software and according to the general method of X-ray diffraction analysis JISK0131-1996.

[0150] Figure 2The XRD pattern of the waste battery material powder of Example 1 contains characteristic diffraction peaks of both graphite and lithium nickel cobalt manganese oxide.

[0151] ③ Carbon content test: LECO CS844 high-frequency combustion infrared sulfur carbon detector of Rigaku Company was used to detect the carbon content percentage of the waste battery material powder according to YS / T1028.4-2015.

[0152] The test results are shown in Table 1.

[0153] Table 1 Test results

[0154]

[0155] (2) Comparison of metal leaching rates corresponding to Examples 1-20.

[0156] Specifically, the test method of the metal leaching rate includes: ICP-OES determination of the metal concentration in the valuable metal extraction liquid, calculation of the content percentage of each metal element and the target metal leaching rate, and the test results are shown in Table 2.

[0157]

[0158] In the formula, the target metal leaching rate is the ratio of the total mass of M elements (M elements are Ni, Co, Mn, Fe and Li contained in the waste battery material powder) in the leaching liquid to the total mass of M elements in the waste battery material powder; c Ni , c Co , c Mn , c Fe , c Li , c Ni , β Co , β Mn , β Fe , β Li are the mass percentages of Ni, Co, Mn, Fe and Li in the waste battery material powder, respectively, in %.

[0159] Among them, the content of metal elements in the waste battery material powder: the percentage content of Ni, Co, Mn, Li and Fe metal elements in the waste battery material powder is determined according to YS / T1342.1, YS / T1342.2, YS / T1342.3, YS / T1342.4 and YS / T1028.1-2015.

[0160] (3) The regenerated graphite obtained in Examples 1-20 was prepared into a button cell in the following manner, and the electrochemical performance of the button cell was tested.

[0161] The preparation method comprises:

[0162] Preparation of electrode: the regenerated graphite, acetylene black and binder (PVDF) were mixed in a mass ratio of 93:5:2, then NMP was added to homogenize to obtain a slurry, the slurry was coated on a copper foil using a doctor blade, then dried in an oven at 120°C for 12 h, and then pressed, cut and weighed using a punch press to obtain a graphite electrode sheet.

[0163] Preparation of button cell: in an argon atmosphere (H2O < 0.01 ppm, O2 < 0.01 ppm) glove box, a button cell was assembled using a CR2025 type battery shell, a polypropylene porous membrane was used as a separator, the electrolyte solute was 1 mol / L LiPF6, and the electrolyte solvent was EC, DEC and EMC in a volume ratio of 1:1:1, the prepared graphite electrode sheet was placed in the positive shell, a high-purity lithium sheet (≥99.9 wt%) was placed in the negative shell as a counter electrode, and then sealed using a battery sealing machine, and tested after standing for 24 h.

[0164] Electrochemical performance test: a multi-channel battery tester (NEWARE CT-3008) was used for testing, and the voltage range of the charge and discharge was 0.005V-2.0V.

[0165] The results are shown in Table 2.

[0166] Table 2 Test results

[0167]

[0168]

[0169] Comprehensive analysis of Tables 1 and 2, the I D / I G > 0.5, and the metal leaching rate and the electrochemical performance of the obtained regenerated graphite were worse than those of Examples 1-16; in Comparative Example 1, the dried fine material was pyrolyzed under an oxygen concentration of 25 vol%, resulting in a high degree of graphite oxidation, so the G band half-width and I2 / I1 were both large, and I D / I G > 0.5.

[0170] Example 2, compared with Example 1, due to the low oxygen content during pyrolysis, the content of amorphous carbon was high, with a carbon content of 27.26%, so although I D / I G < 0.5, but The metal leaching rate was lower than that of Example 1 because it exceeded the range of 0.19 to 0.4, and the electrochemical performance of the resulting recycled graphite was also inferior to that of Example 1.

[0171] Examples 1, 3, and 4 have similarities. The carbon content indicates that the waste battery material powder in these embodiments has a similar amorphous carbon content; however, due to the inconsistent oxidation degree of graphite in these three embodiments, the three embodiments have different I values. D / I G The values ​​of d1, G-band half-width at half-maximum (FWHM), and I2 / I1 are also observed. Comparison shows that the higher the oxidation degree of the waste battery material powder, the larger the FWHM and I2 / I1 values, and the greater the I2 / I1 value. D / I G The higher the value, the lower the metal leaching rate and the worse the electrochemical performance of the recycled graphite.

[0172] Examples 3, 5, and 6 have similar G-band half-widths and I2 / I1 values, indicating that the graphite oxidation degree in the waste battery material powder is similar; however, due to the different amorphous carbon content, I... D / I G The values ​​differ. Specifically, the higher the amorphous carbon content in the waste battery material powder, the higher the I... D / I G value, d1 and The larger the carbon content, the lower the metal leaching rate. The specific capacity of the recycled graphite initially increases and then decreases, with the initial efficiency and cycle capacity retention decreasing progressively. Since amorphous carbon has high porosity and specific surface area, an appropriate amorphous carbon content can improve the capacity of recycled graphite. However, excessive amorphous carbon content leads to increased resistance and poor conductivity, resulting in decreased capacity. Furthermore, the numerous internal structural defects in amorphous carbon cause lithium to form a SEI film during the first charge and discharge, creating "dead lithium," resulting in a low initial efficiency. As the number of cycles increases, more and more lithium is inserted but cannot be properly extracted, leading to a low cycle capacity retention.

[0173] The waste battery material powder in Example 7 was derived from waste lithium cobalt oxide batteries. Due to the high leaching efficiency of cobalt, the metal leaching rate was higher than that in Examples 1-6. However, the graphite in Example 7 had a high degree of oxidation (G-band half-width reached 46.67 cm). -1 (I2 / I1 value is 0.19), its I D / I G The value is 0.39 and d1 is 0.3408 nm, therefore the electrochemical performance of the obtained recycled graphite is worse than that of Example 1.

[0174] The waste battery material powder in Examples 8 and 9 came from waste lithium iron phosphate batteries. Example 9 had a higher carbon content, and ID / I G The value and d1 are larger, Exceeds the range of 0.19-0.40, so the metal leaching rate is lower than that of Example 8, and the electrochemical performance of the regenerated graphite obtained is also poor.

[0175] From Example 1, Examples 10-12, it can be seen that within the mass ratio range of the coarse material and the solvent provided by the present application, the waste battery material powder obtained has a good metal leaching rate in hydrometallurgy, and the electrochemical performance of the regenerated graphite obtained is excellent, which shows that dispersing and ball milling the coarse material with a small amount of organic solvent can effectively remove the binder. However, if the amount of solvent is too small, such as the mass ratio of coarse material to solvent of 1:0.1 used in Example 12, the small amount of organic solvent is difficult to play a role in dissolving the binder, and it is difficult to fully expose it, so it cannot be completely removed during subsequent fluidized drying and pyrolysis, resulting in an increase in carbon content and powder agglomeration, ultimately reducing the metal leaching rate. At the same time, the residual organic matter is transferred to the graphite residue, reducing the performance of the regenerated graphite.

[0176] From Example 1, Examples 13-14, and Comparative Examples 1-2, it can be seen that the concentration of oxygen during pyrolysis has a great influence on the performance of the waste battery material powder. Too low oxygen content leads to too much amorphous carbon, and too high oxygen content leads to high degree of graphite oxidation, both of which are not conducive to reducing I D / I G , and the performance of the regenerated graphite is poor.

[0177] From Example 1, Examples 15-16, and Comparative Example 4, it can be seen that microwave treatment is beneficial to reducing I D / I G , improving the metal leaching rate of the waste battery material powder and the electrochemical performance of the regenerated graphite. The local high temperature and overheating effect in the form of electric arc plasma generated by microwave treatment can remove impurities and reconstruct the structure of graphite.

[0178] From Example 1 and Comparative Example 3, it can be seen that fluidized drying is beneficial to reducing the content of amorphous carbon compared to ordinary drying, thereby improving the metal leaching rate and the electrochemical performance of the regenerated graphite. Comparative Example 3 uses ordinary drying, which causes the powder particles to re-agglomerate and bond during the drying process, and the binder is embedded in the powder particles, which is difficult to remove during subsequent pyrolysis. The residual binder or binder pyrolysis product is difficult to gasify, which agglomerates the material powder particles together, resulting in a low metal leaching rate, and the electrochemical performance of the regenerated graphite is poor due to the presence of too much organic matter or disordered carbon in the graphite residue.

[0179] In summary, the content of carbon element provided by the present application is 10wt%-40wt% and I D / I GThe waste battery material powder with less than 0.5 has a lower content of amorphous carbon and a lower oxidation degree of graphite, and can have a good metal element recovery rate in a hydrometallurgical process, so that the obtained graphite residue has a good regeneration capacity. The preparation method of the waste battery material powder provided by the application effectively reduces the content of amorphous carbon in the waste battery material powder and the oxidation degree of graphite by combining various means including wet ball milling, limited oxygen pyrolysis and microwave radiation, and the like, so that the waste battery material powder has a lower I D / I G of the waste battery material powder.

[0180] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A waste battery material powder, characterized by, The waste battery material powder comprises metal compound powder and elemental carbon material, the content of carbon element in the waste battery material powder is 10wt%-40wt%, and I D / I G ≤0.5, wherein, I D , I G are the intensity of D band characteristic peak and G band characteristic peak in the Raman spectrum of the waste battery material powder respectively, the wave number of the D band characteristic peak is 1300cm -1 -1400cm -1 , and the wave number of the G band characteristic peak is 1500cm -1 -1600cm -1 . The waste battery material powder I D I G I1 and I2 satisfy the following relationship: 0.19 ≤ ( )-( )≤0.4; where I1 is the peak intensity of characteristic peak 1 and I2 is the peak intensity of characteristic peak 2; in the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ=26°~27° is characteristic peak 1; the characteristic peak corresponding to 2θ=10°~12° is characteristic peak 2.

2. The waste battery material powder according to claim 1, characterized by, The waste battery material powder also has at least one of the following characteristics: Feature 1: the half-height width of the G-band characteristic peak is lower than 50 cm -1 ; Characteristic 2: In the XRD spectrum of the waste battery material powder, the characteristic peak corresponding to 2θ=26°~27° is characteristic peak 1, and the interplanar spacing corresponding to the characteristic peak 1 is 0.3354nm~0.3420nm; Characteristic 3: I2 / I1 is 0~0.2; Characteristic 4: The metal in the metal compound powder includes at least one of lithium, nickel, cobalt, manganese and iron.

3. The waste battery material powder according to claim 2, characterized by, The I value of the waste battery material powder is 0.19-0.

48. D / I G The I value of the waste battery material powder is 0.19-0.

48.

4. A method of producing a waste battery material powder as claimed in any one of claims 1 to 3, characterized by, The method comprises the following steps: crushing, first drying and sorting the waste battery monomer to be treated to obtain coarse material containing positive electrode active material and negative electrode active material; Mixing and ball-milling the coarse material with a solvent to obtain wet material; Second drying and then pyrolysis of the wet material to obtain oxidized material; Microwave treatment of the oxidized material to obtain a waste battery material powder.

5. The preparation method according to claim 4, characterized in that, The temperature of the first drying is 180℃~240℃, and the time is 1h~3h; And / or, the second drying is carried out by using a fluidized bed drying method, the temperature is 80℃~120℃, the time is 1h~3h, and the air inlet frequency is 20Hz~40Hz.

6. The preparation method according to claim 4, characterized in that, The mass ratio of the coarse material to the solvent is 1:0.2 to 1:0.4; And / or, the particle size of the coarse material is ≤5cm; And / or, the particle size of the wet material is ≤500μm.

7. The preparation method according to claim 4, characterized in that, The pyrolysis is carried out under the condition that the oxygen concentration is 10vt%~20vt%.

8. The preparation method according to claim 4, characterized in that, The power of the microwave treatment is 400W~800W, and the time is 10min~30min.

9. Use of the waste battery material powder according to any one of claims 1 to 3, characterized in that, The waste battery material powder is used for wet metallurgical recovery of metal materials and graphite.

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