Waste battery material powder as well as preparation method and application thereof

Abstract

The invention discloses waste battery material powder as well as a preparation method and application thereof, and belongs to the technical field of battery recovery. The waste battery material powder comprises metal compound powder and a simple substance carbon material, the content percentage of carbon in the waste battery material powder is 10-40 wt%, ID / IG is smaller than or equal to 0.5, and ID and IG are the intensity of a D-band characteristic peak and the intensity of a G-band characteristic peak in a Raman spectrum of the waste battery material powder respectively. The waste battery material powder has a relatively low ID / IG value, which indicates that the waste battery material powder has relatively low amorphous carbon content and relatively low oxidation degree of graphite; the waste battery material powder meeting the requirements that the content percentage of the carbon element is 10 wt%-40 wt% and ID / IG is smaller than or equal to 0.5 has the good metal recovery rate in the hydrometallurgy process, and the obtained graphite slag can have the good regeneration capacity.

Description

Technical Field

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

[0002] With the rapid development of science and technology, the market demand for new energy, especially new energy vehicles, continues to expand. As its core component, lithium batteries have been widely used. However, the subsequent problem of retired battery disposal has become a bottleneck in the development of the industry. Waste battery powder recycling technology has emerged to recycle and reuse the valuable metals and materials in waste batteries, realizing the green transformation of waste into treasure.

[0003] Waste battery powder mainly comes from the dismantling, crushing and screening of waste lithium batteries. Its main components include valuable metals such as lithium, cobalt, nickel and manganese and non-metallic materials such as carbon powder and plastic. If waste batteries are not properly handled, the loss of valuable metals will lead to waste of resources, while non-metallic materials such as carbon powder and plastic will pollute soil and water sources.

[0004] At present, 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 the metal from other impurities through high-temperature smelting and reduction reaction to obtain metal elements. This method has low waste utilization rate, high energy consumption and pollution, and can only obtain metal alloys. Direct regeneration refers to solving the failure problem of materials in a targeted manner without 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 currently cannot meet the application requirements. Hydrometallurgy refers to ionizing metal elements, and then separating and enriching the metals through precipitation, electrolysis, extraction, ion exchange and other technologies, and finally recovering the target metal in the form of a certain chemical state. This method can obtain relatively pure metal compounds for direct use in the preparation of electrode materials.

[0005] Specifically, the hydrometallurgical process includes acid leaching, that is, putting the waste battery material powder into a solution containing a reducing agent (usually hydrogen peroxide) and concentrated acid (usually sulfuric acid) to ionize the valuable metals and retain them in the liquid phase, and then separate the insoluble matter (called "graphite slag") by 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 usually adsorbs and carries a certain amount of valuable metal ions (such as lithium ions, nickel ions, cobalt ions, manganese ions and iron ions, etc.), which reduces the recovery rate of valuable metals on the one hand, and the metals remaining in the graphite slag are not easy to handle on the other hand, which makes it difficult to regenerate the graphite slag and can only be discharged as solid waste.

[0006] In view of this, the present invention is proposed. Summary of the invention

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

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a waste battery material powder, the waste battery material powder comprises a metal compound powder and a single carbon material, the content of carbon in the waste battery material powder is 10wt% to 40wt%, and I D / I G ≤0.5, where I D ,I G They are the intensities of the characteristic peaks of the D band and the G band in the Raman spectrum of waste battery material powder. The wave number of the characteristic peak of the D band is 1300 cm -1 ~1400cm -1 The wave number of the characteristic peak of the G band is 1500 cm -1 ~1600cm -1 .

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

[0011] Feature 1: The half-width of the G band characteristic peak is less than 50 cm -1 ;

[0012] Feature 2: In the XRD spectrum of waste battery material powder, the characteristic peak corresponding to 2θ=26°~27° is characteristic peak 1, and the crystal plane spacing corresponding to characteristic peak 1 is 0.3354nm~0.3420nm;

[0013] Feature 3: In the XRD spectrum of 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, and the peak intensity ratio I2 / I1 of characteristic peak 2 and characteristic peak 1 is 0~0.2;

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

[0015] In an optional embodiment, I D / I G The value 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 invention provides a method for preparing waste battery material powder as described in any one of the aforementioned embodiments, comprising the following steps: crushing, first drying, and sorting the waste battery monomers to be processed to obtain a coarse material containing positive electrode active materials and negative electrode active materials;

[0018] The coarse material is mixed with the solvent and ball-milled to obtain a wet material;

[0019] The wet material is subjected to a second drying and then pyrolyzed to obtain an oxidized material;

[0020] The oxidized material is subjected to microwave treatment to obtain waste battery material powder.

[0021] In an optional embodiment, the first drying temperature is 180°C to 240°C, and the time is 1h to 3h;

[0022] And / or, the second drying is carried out by fluidized bed drying; the temperature is 80° C. to 120° C., the time is 1 h to 3 h, and the air frequency is 20 Hz to 40 Hz.

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

[0024] and / or, the particle size of the coarse material is ≤ 5 cm;

[0025] And / or, the particle size of the wet material is ≤500 μm.

[0026] In an optional embodiment, the pyrolysis is carried out under the condition that the oxygen concentration is 10 vt% to 20 vt%.

[0027] In an optional embodiment, the power of the microwave treatment is 400W to 800W, and the time is 10min to 30min.

[0028] In a third aspect, the present invention provides an application of waste battery material powder according to any one of the aforementioned embodiments, such as using the waste battery material powder for hydrometallurgical recovery of metal materials and graphite.

[0029] Beneficial effects of the present invention:

[0030] The carbon content percentage provided by the present invention is 10wt% to 40wt% and I D / I G≤0.5, the waste battery material powder has a low content of amorphous carbon and a low degree of oxidation of graphite, thereby reducing the situation of amorphous carbon carrying valuable metals, so that the waste battery material powder has a good metal element recovery rate in the hydrometallurgical process, and the graphite slag obtained by hydrometallurgy has good regeneration ability. The preparation method of the waste battery material powder provided by the present invention effectively reduces the content of amorphous carbon in the waste battery material powder by combining multiple means including wet ball milling, pyrolysis and microwave radiation, and at the same time reduces the degree of oxidation of graphite, thereby obtaining the waste battery material powder that meets the above conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

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

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

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0035] The waste battery material powder provided by the present invention and its preparation method and application are specifically described below.

[0036] The invention provides waste battery material powder, which comprises metal compound powder and single carbon material.

[0037] The metal in the above-mentioned metal compound powder includes at least one of lithium, nickel, cobalt, manganese and iron. When the waste battery material powder is lithium iron phosphate waste battery powder, the mass percentage of iron in the waste battery material powder may not exceed 30% (such as 10%, 15%, 20%, 25% or 30%, etc.); when the waste battery material powder is nickel cobalt manganese oxide lithium waste battery powder, the mass percentage of nickel in the waste battery material powder may be 10% to 50% (such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc.), and the mass percentage of cobalt in the waste battery material powder may not exceed 30% (such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc.). The mass percentage of manganese in the waste battery material powder may not exceed 30%; the mass percentage of manganese in the waste battery material powder may not exceed 30%; when the waste battery material powder is lithium cobalt oxide waste battery powder, the mass percentage of cobalt in the waste battery material powder may not exceed 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 may not exceed 10% (such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.).

[0038] The sources of elemental carbon materials in waste battery material powder include graphite negative electrode, conductive agent and organic decomposition residue, etc. Elemental carbon is divided into graphite carbon and non-graphite carbon. Graphite carbon mainly comes from graphite negative electrode, and non-graphite carbon mainly comes from conductive agent and organic decomposition residue.

[0039] Graphite carbon has a regular layered structure, high crystallinity, no crystal defects, low porosity, low interlayer spacing, and high hydrophobicity; non-graphite carbon is amorphous, contains crystal defects, and has low crystallinity, high porosity, large interlayer spacing, and high hydrophilicity. The high porosity and large interlayer spacing of non-graphite carbon make it easy to carry valuable metal ions, which in turn leads to a lower metal leaching rate during hydrometallurgy; and the metal elements remaining in the graphite slag need to be further removed before the graphite slag can be regenerated. Therefore, the lower the metal leaching rate during the hydrometallurgy process, the lower the regeneration of the corresponding graphite slag and the higher the regeneration cost.

[0040] In the present invention, the content of carbon in the waste battery material powder is 10wt% to 40wt%, and I D / I G ≤0.5. Among them, I D ,I G They are the intensities of the characteristic peaks of the D band and the G band in the Raman spectrum of the waste battery material powder. The wave number of the characteristic peak of the D band is 1300 cm -1 ~1400cm -1 The wave number of the characteristic peak of the G band is 1500 cm -1 ~1600cm -1The waste battery material powder that meets the above conditions has a higher metal leaching rate, and the graphite slag obtained after acid leaching has good regeneration properties.

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

[0042] In some optional embodiments, I D / I G The value of may be 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15 or 0.1, etc., or may be other values ​​within the range of ≤0.5 or other ranges, for example, 0.19 to 0.48. In some typical embodiments, I D / I G The value is 0.28~0.43.

[0043] As mentioned above, the waste battery material powder provided by the present invention has a lower I D / I G The value indicates that its non-graphite carbon content is low, so it adsorbs or carries less metal ions during the hydrometallurgical process, which is beneficial to improve the metal leaching rate during the acid leaching process, and the obtained graphite slag has a higher purity, which can reduce the process and cost of the graphite slag regeneration process. Specifically, the 1500cm -1 ~1600cm -1 The corresponding G band characteristic peak represents the carbon atom sp 2 Hybrid in-plane stretching reflects the ordered structure of graphite; 1300cm -1 ~1400cm -1 The corresponding D band characteristic peak represents the defects in the carbon atom lattice, reflecting the defects or disordered structure of graphite. The intensity ratio of the G band characteristic peak to the D band characteristic peak is D / I G The disorder degree of carbon materials can be evaluated. D / I G The smaller the value, the higher the degree of order of the carbon material and the smaller the number of defects, that is, the lower the non-graphite carbon content in the carbon material.

[0044] It should be noted that non-graphite carbon includes amorphous carbon and graphite oxide. No sharp peaks are observed in the XRD spectrum of amorphous carbon, only envelope peaks, and no G-band characteristic peaks are observed in the Raman spectrum. Graphite oxide is the product of graphite oxidation treatment. The defects and disordered structure introduced by oxidation increase the interlayer spacing of graphite. Therefore, compared with graphite, the intensity of the D-band characteristic peak of graphite oxide is stronger.

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

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

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

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

[0049] The above-mentioned characteristic peak 1 corresponds to the (002) crystal plane between graphite layers. The smaller the inter-plane spacing, the higher the degree of graphitization of the material and the smaller the inter-layer spacing. It is more difficult for metal ions to be intercalated and carried in graphite during hydrometallurgy, which is more conducive to improving the metal recovery rate. The inter-plane spacing of the (002) crystal plane of graphite reflects the degree of damage to the graphite negative electrode during the use of the battery. During the lithium ion intercalation and deintercalation cycle, or even when the electrolyte is co-intercalated, the inter-layer spacing of the graphite negative electrode will continue to increase, resulting in an 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 inter-plane spacing.

[0050] In some optional embodiments, in the XRD spectrum of 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, and the peak intensity ratio I2 / I1 of characteristic peak 2 and characteristic peak 1 is 0~0.2, such as 0~0.19.

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

[0052] The characteristic peak 2 corresponds to the (001) crystal plane of graphite oxide. The peak intensity of the characteristic peak can reflect the degree of graphite oxidation. The higher the degree of graphite oxidation, the greater the I2. The oxidation of graphite will increase the interlayer spacing of its crystals, which is not conducive to improving the metal leaching rate of hydrometallurgy and the regeneration of graphite slag.

[0053] In some optional embodiments, I D ,I G , I1 and I2 satisfy the following relationship: For example, The value of can be 0.19, 0.25, 0.3, 0.35 or 0.4, etc., or can be other values ​​within 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 has a higher metal leaching rate in hydrometallurgy, and the graphite slag obtained has a higher regeneration performance. As mentioned above, It reflects the degree of structural order of carbon 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. It reflects the oxidation degree of graphite in waste battery material powder. and The difference reflects the contribution of amorphous carbon to the overall disorder. Compared with graphite oxide structure, amorphous carbon has a stronger ability to adsorb and carry metal ions. The reason is that the former is based on the electrostatic adsorption of surface groups and intercalation between carbon layers to achieve metal ion adsorption and carrying, while the latter is based on the rich pore structure to adsorb and load metal ions. Therefore, further control of waste battery material powder makes waste battery material powder have a lower value, which is beneficial to improve the metal leaching rate. In addition, amorphous carbon is difficult to be converted into graphite during graphite regeneration, so the content of amorphous carbon will eventually affect the content of amorphous carbon in the regenerated graphite, thereby affecting its electrochemical properties.

[0055] Accordingly, the present invention also provides a method for preparing the above waste battery material powder, comprising the following steps: crushing, first drying, and sorting the waste battery monomers to be processed to obtain a coarse material containing positive electrode active materials and negative electrode active materials;

[0056] The coarse material is mixed with the solvent and ball-milled to obtain a wet material;

[0057] The wet material is subjected to a second drying and then pyrolyzed to obtain an oxidized material;

[0058] The oxidized material is subjected to microwave treatment to obtain waste battery material powder.

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

[0060] In some optional embodiments, the crushing method may exemplarily but not limitatively include at least one of jaw crushing, hammer crushing, cone crushing, impact crushing, ball mill crushing, rod mill crushing, roller crushing and high-pressure roller mill to achieve the crushing of battery cells.

[0061] In some optional embodiments, the temperature of the first drying can be 180°C to 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, etc., or other values ​​within the range of 180°C to 240°C.

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

[0063] Sorting refers to removing or partially removing plastic, aluminum foil, copper foil, aluminum shell and steel shell by screening, density sorting, electrical sorting, optical sorting, vibration sorting, etc., to obtain coarse materials enriched with positive electrode active materials and negative electrode active materials. Among them, the negative electrode active material includes graphite; the positive electrode active material includes at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and lithium iron phosphate.

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

[0065] In some optional embodiments, the solvent used for ball milling can illustratively but not limitatively include at least one of N-methylpyrrolidone (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, or other values ​​within the range of 1:0.2 to 1:0.4.

[0066] The above-mentioned solvent can dissolve the binder well. The above-mentioned solvent and the coarse material are mixed and ball-milled, which can accelerate the shedding of the binder, so that the active material and the current collector and the particles of different active materials can be quickly separated, and it is beneficial for the binder to be quickly decomposed during subsequent pyrolysis. In addition, by ball milling, the particle size of the powder can be reduced, the specific surface area of ​​the powder can be increased, and then the heating area during the pyrolysis of the powder can be increased, the pyrolysis effect can be improved, and it is beneficial to improve the leaching efficiency of the positive electrode active material in the hydrometallurgical process. Compared with soaking the waste battery materials in an organic solvent, the present invention uses a mass ratio greater than 1 to mix the coarse material and the solvent for ball milling, which can not only reduce the use of organic reagents, but also 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 fluidized bed drying.

[0069] The present invention places the wet material after ball milling on a fluidized bed for drying, which can avoid the particles from re-bonding after the solvent evaporates, and can expose organic matter and amorphous carbon on the particle surface to increase its specific surface area, thereby facilitating subsequent pyrolysis and gasification.

[0070] Exemplarily, the second drying temperature can be 80°C to 120°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, etc., or other values ​​within the range of 80°C to 120°C.

[0071] The second drying time may be 1 h to 3 h, such as 1 h, 1.5 h, 2 h, 2.5 h or 3 h, or other values ​​within the range of 1 h to 3 h.

[0072] The air inlet frequency of the second drying may be 20 Hz to 40 Hz, such as 20 Hz, 25 Hz, 30 Hz, 35 Hz or 40 Hz, or may be other values ​​within the range of 20 Hz to 40 Hz.

[0073] In the present invention, pyrolysis is carried out in an oxygen-limited environment. In some optional embodiments, pyrolysis is carried out under the condition of an oxygen concentration of 10vt% to 20vt%. The oxygen concentration may be 10vt%, 15vt% or 20vt%, or other values ​​within the range of 10vt% to 20vt%.

[0074] The present invention pyrolyzes the material after the second drying under oxygen-limited conditions and controls the oxygen concentration to be 10vt% to 20vt%, which is beneficial to the rapid gasification and decomposition of amorphous carbon and avoids excessive oxidation of graphite.

[0075] In some optional 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 microwave treatment time can be 10 min to 30 min, such as 10 min, 15 min, 20 min, 25 min or 30 min, etc., or other values ​​within the range of 10 min to 30 min.

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

[0078] The present invention performs microwave treatment on the oxidized material in an inert atmosphere, which can produce a local overheating effect inside the material, thereby achieving the effect of repairing the graphite structure and reducing the oxidation degree thereof.

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

[0080] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0081] Example 1

[0082] This embodiment 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 batteries are crushed by double-axis shearing and single-axis crushing in sequence under nitrogen protection, and the crushed materials are first dried for 2 hours at 190℃~200℃ in a nitrogen atmosphere, and then broken up and sieved with a disperser to obtain large pieces of material (protective shell) and small pieces of material; the small pieces of material are sieved with a circular vibrating screen, and the screened material is coarse material, and the particle size of the coarse material is controlled to be ≤3cm.

[0084] S2: The crude material and the 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: placing the wet material in a fluidized bed for a second drying, the second drying temperature is 100°C, the air frequency is 30Hz, and the drying time is 2h to obtain a dry fine material; then placing the dry fine material in a rotary kiln, pyrolyzing it under oxygen limitation (oxygen concentration is 10vt%) and 500°C for 1.5h to obtain an oxidized material;

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

[0087] Example 2

[0088] The difference between this embodiment and embodiment 1 is that: in S1, the battery cell is a ternary soft pack; in S2, the mass ratio of the coarse material to the solvent is 1:0.2; in S3, the second drying temperature is 80°C, the air frequency is 20Hz, and the second drying time is 1h; the pyrolysis is carried out in an environment with an oxygen concentration of 5vt%, and the pyrolysis time is 2h.

[0089] Example 3

[0090] 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; in S3, the pyrolysis is carried out in an environment with an oxygen concentration of 15vt%, and the pyrolysis time is 2h.

[0091] Example 4

[0092] 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°C, the pyrolysis is carried out in an environment with an oxygen concentration of 20vt%, the pyrolysis temperature is 550°C, and the pyrolysis time is 2h.

[0093] Example 5

[0094] 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; in S3, the temperature of the second drying is 120°C, the air inlet frequency is 40Hz, the pyrolysis is carried out in an environment with an oxygen concentration of 15vt%, and the pyrolysis time is 2h; 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 second drying temperature is 120°C, the air inlet frequency is 20 Hz, the second drying temperature is 1 h, the pyrolysis temperature is 450°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] Example 7

[0098] The difference between this embodiment and embodiment 1 is that: in S1, the battery cell is an LCR soft pack, the temperature of the first drying is 230°C to 240°C, and the particle size of the coarse material is ≤5cm; in S3, the temperature of the second drying is 120°C, the air intake frequency is 40Hz, the time of the second drying is 3h, the pyrolysis temperature is 550°C, the pyrolysis is carried out in an environment with an oxygen concentration of 20vt%, and the pyrolysis time is 2h; in S4, the microwave power is 600W.

[0099] Example 8

[0100] The difference between this embodiment and embodiment 1 is that: in S1, the battery cell is an LFP aluminum shell, and the temperature of the first drying is 180°C to 190°C; 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°C, the air intake frequency is 40Hz, the time of the second drying is 1h, and the pyrolysis is carried out in an environment with an oxygen concentration of 15vt%, and the pyrolysis time is 2h.

[0101] Example 9

[0102] The difference between this embodiment and embodiment 1 is that: in S1, the battery cell is an LFP aluminum shell, and the temperature of the first drying is 180°C to 190°C; 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°C, the air inlet frequency is 20Hz, and the time of the second drying is 3h; in S4, the microwave power is 700W, and the microwave treatment time is 10min.

[0103] Example 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] Example 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] Embodiment 13

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

[0111] Embodiment 14

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

[0113] Embodiment 15

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

[0115] Example 16

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

[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 25vt%.

[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 0vt%.

[0121] Comparative Example 3

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

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

[0127] The hydrometallurgical application of application examples 1 to 7 and application examples 10 to 20 includes the following steps:

[0128] (a) putting the waste battery material powder into an acid leaching solution (a sulfuric acid solution with a pH of 0.5 to 1 and a hydrogen peroxide volume concentration of 20%) at a solid-liquid ratio of 1 g:10 mL, stirring at 80° C. for 6 h, monitoring the pH and adding sulfuric acid during the process, controlling the pH of the acid leaching solution to 1 to 1.5, and separating the solid and liquid to obtain the acid leaching solution and acid leaching residue;

[0129] (b) putting the acid leaching residue into ionized water to obtain a slurry with a solid content of 200 g / L, stirring at 60° C. for 1 hour, separating the solid and the liquid to obtain a washed liquid and a washed residue; concentrating the washed liquid and combining it with the acid leaching liquid to obtain a valuable metal extract;

[0130] (c) washing the washed slag with water until it becomes neutral, and drying it at 80° C. to a constant weight to obtain purified graphite;

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

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

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

[0134] (b) putting the acid leaching residue into ionized water to obtain a slurry with a solid content of 200 g / L, stirring at 60° C. for 1 hour, separating the solid and the liquid to obtain a washed liquid and a washed residue; concentrating the washed liquid and combining it with the acid leaching liquid to obtain a valuable metal extract;

[0135] (c) washing the washed slag with water until it becomes neutral, and drying it at 80° C. to a constant weight to obtain purified graphite;

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

[0137] The chemical reactions involved in the acid leaching process in the above hydrometallurgical applications 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-xy)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 to 16 and Comparative Examples 1 to 4 was tested, and the testing method included:

[0147] ①. Raman spectroscopy: German WITec alpha300R Raman spectrometer is used to characterize waste battery material powder, with a scanning range of 50cm -1 ~4000cm -1 , the excitation wavelength is 532nm, at least 3 points are measured for each sample, and the I D / I G The half-height width of the G band is averaged, and the obtained average value needs to satisfy the coefficient of dispersion (= standard deviation ÷ average value) ≤ 0.2. The half-height width of the characteristic peak of the G band can be fitted and analyzed by software such as Origin and PeakFit. For example, the characteristic peak of the G band in Table 1 of the present invention is obtained by the following analysis method: the Raman curve is baseline-subtracted using Origin software, and then Gaussian fitting is performed to obtain the half-height width, and the goodness of fit COD is required to be above 0.9.

[0148] Figure 1 The Raman spectra of the waste battery material powder of Example 1 and Comparative Example 1 after baseline subtraction.

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

[0150] Figure 2This is the XRD spectrum of the waste battery material powder of Example 1, which contains characteristic diffraction peaks of graphite and lithium nickel cobalt manganese oxide.

[0151] ③. Carbon content test: Use LECO CS844 high-frequency combustion infrared sulfur-carbon detector to detect the carbon content percentage of waste battery material powder in accordance with YS / T1028.4-2015.

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

[0153] Table 1 Test results

[0154]

[0155] (2) The metal leaching rates obtained in accordance with Examples 1 to 20 are compared.

[0156] Specifically, the test method of the metal leaching rate includes: performing ICP-OES measurement on the metal concentration in the valuable metal extract, calculating the content percentage of each metal element and the target metal leaching rate, and the test results are shown in Table 2.

[0157]

[0158] Wherein, 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 leached solution to the total mass of M elements in the waste battery material powder; c Ni 、c Co 、c Mn 、c Fe 、c Li are the concentrations of Ni, Co, Mn, Fe and Li in the acid leaching solution, in g / L; V is the volume of the acid leaching solution, in L; M0 is the amount of waste battery material powder, in g; β Ni , β Co , β Mn , β Fe , β Li They are the mass percentages of Ni, Co, Mn, Fe and Li in the waste battery material powder, in %.

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

[0160] (3) The regenerated graphites obtained in Application Examples 1 to 20 were prepared into button-type batteries in the following manner, and the electrochemical properties of the batteries were tested.

[0161] The preparation method comprises:

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

[0163] Preparation of button-type batteries: In a glove box with argon atmosphere (H2O <0.01ppm, O2 <0.01ppm), button-type batteries were assembled using CR2025 battery shells, a polypropylene porous membrane was used as a separator, the electrolyte solute was 1 mol / L LiPF6, 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 electrode shell, and a high-purity lithium sheet (≥99.9wt%) was placed in the negative electrode shell as a counter electrode, and then sealed with a battery sealer and tested after standing for 24 hours.

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

[0165] The results are shown in Table 2.

[0166] Table 2 Test results

[0167]

[0168]

[0169] Comprehensive analysis of Table 1 and Table 2, the comparative example I D / I G >0.5, the metal leaching rate and the electrochemical performance of the obtained regenerated graphite are worse than those of Examples 1 to 16; in Comparative Example 1, the dried fine material is pyrolyzed under the condition of an oxygen concentration of 25vt%, so that the degree of graphite oxidation is high, so the half-height width of the G band and I2 / I1 are large, and I D / I G >0.5.

[0170] Compared with Example 1, Example 2 has a higher amorphous carbon content due to the lower oxygen content during pyrolysis, with the carbon content percentage as high as 27.26%. D / I G <0.5, but It exceeds the range of 0.19 to 0.4, so its metal leaching rate is lower than that of Example 1, and the electrochemical performance of the obtained regenerated graphite is also not as good as that of Example 1.

[0171] Embodiment 1, embodiment 3 and embodiment 4 have similar and carbon content, indicating that the waste battery material powders in these embodiments have similar amorphous carbon content; however, due to the inconsistent oxidation degree of graphite in the three embodiments, the three embodiments have different I D / I G , d1, G band half-height width and I2 / I1 value. By comparison, it can be seen that the higher the oxidation degree of the waste battery material powder, the larger the G band half-height width and I2 / I1 value, and the larger the I D / I G The larger the value, the lower the metal leaching rate and the worse the electrochemical performance of the recycled graphite.

[0172] Example 3, Example 5 and Example 6 have similar G band half-height width and I2 / I1 value, indicating that the oxidation degree of graphite in the waste battery material powder is similar; however, due to the different amorphous carbon content, I D / I G Specifically, the more amorphous carbon content there is in the waste battery material powder, the higher the I D / I G value, d1 and The larger the amorphous carbon content is, the lower the metal leaching rate is. The first charge specific capacity of the obtained regenerated graphite increases first and then decreases, and the first efficiency and cycle capacity retention rate are getting lower and lower. Since amorphous carbon has a high porosity and specific surface area, an appropriate amorphous carbon content can increase the capacity of the regenerated graphite. However, when the amorphous carbon content is too high, the resistance of the regenerated graphite increases and the conductivity is poor, so the capacity decreases. In addition, due to the large number of internal structural defects in amorphous carbon, lithium builds an SEI film to form "dead lithium" during the first charge and discharge, so the first efficiency is low, and as the number of cycles increases, more and more lithium cannot be removed normally after being embedded, resulting in a low cycle capacity retention rate.

[0173] The waste battery material powder of Example 7 comes from waste lithium cobalt oxide batteries. Due to the high leaching efficiency of cobalt element, the metal leaching rate obtained is higher than that of Examples 1 to 6. However, due to the high oxidation degree of graphite (the half-height width of the G band is 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, so the electrochemical performance of the obtained regenerated graphite is worse than that in Example 1.

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

[0175] It can be seen from Examples 1 and 10 to 12 that within the mass ratio range of the coarse material and the solvent provided by the present invention, the obtained waste battery material powder has a good metal leaching rate during hydrometallurgy, and the obtained graphite slag has excellent electrochemical performance after regeneration, indicating that the binder can be effectively removed by using less organic solvent to disperse the coarse material and perform ball milling. However, if the amount of solvent is too small, such as the mass ratio of coarse material and solvent used in Example 12 is 1:0.1, it is difficult to play the role of dissolving the binder due to too little organic solvent, and it is difficult to fully expose it. Therefore, it cannot be completely removed during subsequent fluidized drying and pyrolysis, resulting in an increase in carbon content and powder agglomeration, which ultimately reduces the metal leaching rate. At the same time, the residual organic matter is transferred to the graphite slag, which reduces the performance of the regenerated graphite.

[0176] It can be seen from Example 1, Examples 13 to 14 and Comparative Examples 1 to 2 that the concentration of oxygen during pyrolysis has a great influence on the performance of waste battery material powder. Too low an oxygen content leads to a large amount of amorphous carbon, while too high an oxygen content leads to a high degree of graphite oxidation, both of which are not conducive to reducing I D / I G , so the metal leaching rate and the performance of recycled graphite are poor.

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

[0178] It can be seen from Example 1 and Comparative Example 3 that fluidized drying is more conducive to reducing the content of amorphous carbon than ordinary drying, thereby improving the metal leaching rate and the electrochemical properties of the regenerated graphite. Comparative Example 3 adopts ordinary drying, so that the powder particles are reaggregated and combined during the drying process, and the binder is embedded in the powder particles, which is difficult to remove in the subsequent pyrolysis. Since the residual binder or the binder pyrolysis product is difficult to gasify, the material powder particles are agglomerated together, resulting in a low metal leaching rate. Since too much organic matter or disordered carbon remains in the graphite slag, the electrochemical properties of the regenerated graphite are poor.

[0179] In summary, the carbon content percentage provided by the present invention is 10wt% to 40wt% and I D / I G≤0.5, the waste battery material powder has a low content of amorphous carbon and a low degree of oxidation of graphite, can have a good metal element recovery rate in the hydrometallurgical process, so that the obtained graphite slag has good regeneration ability. The preparation method of the waste battery material powder provided by the present invention effectively reduces the content of amorphous carbon in the waste battery material powder and reduces the degree of oxidation of graphite by combining multiple means including wet ball milling, oxygen-limited pyrolysis and microwave radiation, thereby obtaining a waste battery material powder with low I D / I G Powder of waste battery materials.

[0180] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A waste battery material powder, characterized in that: The waste battery material powder comprises metal compound powder and single carbon material, the content percentage of carbon element in the waste battery material powder is 10wt% to 40wt%, and I D / I G ≤0.5, where I D ,I G are respectively the intensities of the characteristic peaks of the D band and the G band in the Raman spectrum of the waste battery material powder, and the wave number of the characteristic peak of the D band is 1300 cm -1 ~1400cm -1 The wave number of the characteristic peak of the G band is 1500 cm -1 ~1600cm -1 .

2. The waste battery material powder according to claim 1, characterized in that: The waste battery material powder also has at least one of the following characteristics: Feature 1: The half-height width of the characteristic peak of the G band is less than 50 cm -1 ; Feature 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 characteristic peak 1 is 0.3354nm-0.3420nm; Feature 3: 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, and the peak intensity ratio I2 / I1 of the characteristic peak 2 to the characteristic peak 1 is 0-0.2; Feature 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 in that: The waste battery material powder D / I G The value is 0.19~0.

48.

4. The waste battery material powder according to claim 3, characterized in that: The waste battery material powder D ,I G , I1 and I2 satisfy the following relationship:

5. A method for preparing waste battery material powder according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: crushing, first drying and sorting the waste battery monomers to be processed to obtain a coarse material containing positive electrode active materials and negative electrode active materials; Mixing the coarse material with a solvent and ball-milling to obtain a wet material; The wet material is subjected to a second drying and then pyrolyzed to obtain an oxidized material; The oxidized material is subjected to microwave treatment to obtain waste battery material powder.

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

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

8. The preparation method according to claim 5, characterized in that: The pyrolysis is carried out under the condition that the oxygen concentration is 10vt% to 20vt%.

9. The preparation method according to claim 5, characterized in that: The power of the microwave treatment is 400W to 800W, and the time is 10min to 30min.

10. An application of the waste battery material powder as claimed in any one of claims 1 to 4, characterized in that: The waste battery material powder is used for hydrometallurgical recovery of metal materials and graphite.

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