Aluminum slag processing method, aluminum powder and application thereof

Abstract

The present disclosure provides a method for processing aluminum slag, aluminum powder, and applications thereof, belonging to the field of lithium battery technology. The method for processing aluminum slag disclosed herein comprises the following steps: uniformly mixing aluminum slag, graphite, and bicarbonate to obtain a first mixture, wherein the thermal decomposition temperature of the bicarbonate is ≤300°C; grinding the first mixture in a grinder under an inert gas to obtain a second mixture; air-selecting and screening the second mixture to obtain aluminum powder, battery black powder, and graphite, and the obtained graphite is returned to the mixing process. The addition of graphite and bicarbonate with a thermal decomposition temperature of ≤300°C during the grinding process disclosed herein can not only improve the purity of the aluminum powder, but also reduce the grinding temperature, reduce the risk of aluminum slag processing, and improve production safety.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lithium batteries, and in particular to a method for processing aluminum slag, aluminum powder and applications thereof. Background Art

[0002] With global energy shortages and environmental damage becoming increasingly severe, reducing resource consumption and protecting the environment are becoming a widely recognized trend. Lithium-ion batteries, due to their high energy density, high voltage, excellent cycle performance, low self-discharge, and environmental friendliness, are widely used in electric vehicles and various electronic devices, providing humanity with a solution to the energy shortage dilemma. Due to their low cost, safety, excellent thermal stability, and high cycle performance, lithium batteries are widely used in various industries. However, as their service life expires, a large amount of waste lithium-ion batteries is generated, necessitating urgent research into the recycling of these batteries.

[0003] During the lithium battery recycling process, a large amount of aluminum slag containing a large amount of valuable metals is produced. The ground aluminum slag can be used as a raw material for fireworks and firecrackers. The purpose of traditional aluminum slag processing is to dissociate impurities in the aluminum slag to facilitate the subsequent smelting of the aluminum slag. The conventional treatment method for aluminum slag impurity removal is grinding under atmospheric conditions. Under these conditions, grinding will produce a large amount of dust, heat, and hydrogen (the ground aluminum interface reacts with moisture in the air). It can be seen that dust explosions and combustible gas explosions will occur, posing a greater threat to production. For example, the pretreatment feature 1.S1 mentioned in patent CN115595454A: the aluminum slag is sequentially subjected to impurity removal, ball milling, screening, screening, magnetic separation, and then smelting and other processes to obtain aluminum ingots. Since the traditional ball milling process for aluminum slag processing produces a large amount of dust and hydrogen, which seriously threatens production, the processing of aluminum slag from waste batteries is limited, and there is an urgent need to find a safe aluminum slag processing process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for treating aluminum slag, aluminum powder and applications thereof, wherein the treatment method can improve the safety of aluminum slag treatment and the purity of aluminum powder.

[0005] To achieve the above object, the technical solution adopted by the present invention is: providing a method for treating aluminum slag, comprising the following steps:

[0006] uniformly mixing aluminum slag, graphite and bicarbonate to obtain a first mixture, wherein the thermal decomposition temperature of the bicarbonate is ≤300° C.;

[0007] Grinding the first mixture in a grinder under an inert gas to obtain a second mixture;

[0008] The second mixture is air-selected and sieved to obtain aluminum powder, battery black powder and graphite, and the obtained graphite is returned to the mixing process.

[0009] In some embodiments, the mass ratio of the aluminum slag, graphite, and bicarbonate is aluminum slag:graphite:bicarbonate=1000:3-30:1-50.

[0010] In some embodiments, the mass ratio of the aluminum slag, graphite, and bicarbonate is aluminum slag:graphite:bicarbonate=1000:10-20:10-30.

[0011] In some embodiments, the bicarbonate is at least one of sodium bicarbonate, magnesium bicarbonate, calcium bicarbonate, potassium bicarbonate, and barium bicarbonate.

[0012] In some embodiments, the mesh size of the sieve in the sieving step is 100-400 mesh.

[0013] In some embodiments, the feed rate of the grinder is 100-1000 kg / h.

[0014] In some embodiments, the frequency of the grinder is 15-50 Hz.

[0015] In some embodiments, the mixing speed is 300-500 r / min.

[0016] In some embodiments, the mixing time is 30-60 minutes.

[0017] On the other hand, the present disclosure provides aluminum powder obtained by the aluminum slag processing method.

[0018] On the other hand, the present disclosure provides the use of the aluminum powder in the preparation of fireworks and firecrackers.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the present invention adds graphite and bicarbonate during the grinding process of aluminum slag, wherein, on the one hand, the graphite can immediately take away and disperse the heat generated during the grinding process; on the other hand, the bicarbonate undergoes thermal decomposition during the grinding process, and the graphite can further reduce the heat of the grinding system with the help of the thermal decomposition of the bicarbonate; in addition, the carbon dioxide generated by the thermal decomposition of the bicarbonate has a better protective effect on the grinding environment, making the temperature during the grinding process of the aluminum slag controllable; in addition, the graphite and bicarbonate can further reduce the oxygen content during the grinding process, thereby reducing the oxidation rate of the aluminum slag; on another hand, the graphite will not enter the aluminum slag, and due to the low density of the graphite, the aluminum powder and the graphite can be well separated. At the same time, through grinding and screening, the battery black powder and the aluminum powder are separated, and the impurity content of the aluminum powder is reduced, which is conducive to subsequent reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of the processing of aluminum slag disclosed in the present invention;

[0021] Figure 2 is the XRD pattern of the aluminum slag disclosed herein;

[0022] Figure 3 This is the XRD pattern of 2# aluminum powder obtained in Example 3. DETAILED DESCRIPTION

[0023] To facilitate understanding of the present disclosure, a more comprehensive description will be given below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present disclosure.

[0024] For simplicity, this disclosure only explicitly discloses certain numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and similarly, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present disclosure pertains. The terms used herein in the specification of the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. It should be noted that, unless otherwise stated, the term "and / or" used herein includes any and all combinations of one or more related listed items, and "above" and "below" are inclusive of the number, and the meaning of "multiple" in "one or more" is more than two.

[0026] The above-mentioned application content of the present disclosure is not intended to describe each disclosed embodiment or each implementation in the present disclosure. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, the enumeration is only intended as a representative group and should not be construed as exhaustive.

[0027] See Figure 1 The present disclosure provides a method for treating aluminum slag, comprising the following steps:

[0028] A mixer is used to uniformly mix aluminum slag, graphite and bicarbonate to obtain a first mixture, wherein the thermal decomposition temperature of the bicarbonate is ≤300° C.;

[0029] conveying the first mixture to a grinder via a feeder, and grinding the mixture in the grinder under an inert gas to obtain a second mixture;

[0030] The second mixture is air-selected and collected by a cyclone dust collector to obtain a third mixture, and the third mixture is sieved to obtain aluminum powder and battery black powder; graphite is collected by a bag dust collector and returned to the mixer for mixing.

[0031] The cathode material powder on the positive electrode sheet of a lithium-ion battery is bonded to the aluminum current collector via an adhesive. During separation and recycling, the tight bond makes complete separation difficult. Consequently, a high level of cathode material residue (also known as battery black powder) often remains on the aluminum foil, directly impacting the subsequent use of the aluminum slag.

[0032] The present invention adds graphite and bicarbonate with a thermal decomposition temperature of ≤300°C during the grinding process of aluminum slag. On the one hand, the graphite can immediately remove and disperse the heat generated during the grinding process; on the other hand, the bicarbonate undergoes thermal decomposition during the grinding process, and the graphite can further reduce the heat of the grinding system by virtue of the thermal decomposition of the bicarbonate; in addition, the carbon dioxide generated by the thermal decomposition of the bicarbonate has a better protective effect on the grinding environment, making the temperature during the grinding process of the aluminum slag controllable; in addition, the graphite and bicarbonate can further reduce the oxygen content during the grinding process, thereby reducing the oxidation rate of the aluminum slag; on another hand, the graphite will not enter the aluminum slag, and due to the low density of the graphite, the aluminum powder and the graphite can be well separated. At the same time, the battery black powder and the aluminum powder are separated by grinding and screening, thereby reducing the impurity content of the aluminum powder, which is conducive to subsequent reuse. The above aspects work together to reduce the handling risk of the aluminum slag and improve production safety.

[0033] If the thermal decomposition temperature of bicarbonate is greater than 300°C, bicarbonate cannot be decomposed during the grinding process, and cannot play the role of lowering the temperature of the grinding system and improving the purity of the aluminum powder.

[0034] The ground second mixture is sent to the cyclone separator through a closed conveyor, and the second mixture is sorted by airflow. Under the action of centrifugal force, the second mixture is fully dispersed and thrown to the buffer ring. During the falling process, the heavier materials, under the action of the cross airflow generated by the rotor, pass through the blades of the adjustment ring and slide into the cyclone dust collector of the sorter for collection to obtain the third mixture. The third mixture is conveyed to the circular vibrating screen, and the materials are separated according to the particle size of the third mixture to obtain aluminum powder and battery black powder; while the lighter materials are conveyed to the bag dust collector of the sorter below with the airflow from the air suction port in the middle above the rotor under the action of the cross airflow, and are collected and output to obtain graphite, which contains a small amount of battery black powder; the separated graphite can be returned to the mixing process for reuse to reduce resource waste.

[0035] Specifically, the graphite used in the present invention is waste graphite generated in the lithium battery recycling process. The waste graphite cannot be reused, which realizes the resource utilization of waste and reduces the processing cost of aluminum slag.

[0036] Specifically, the inert gas disclosed herein is not limited as long as it can play a protective role, such as nitrogen and argon.

[0037] In some embodiments, the mass ratio of the aluminum slag, graphite and bicarbonate is aluminum slag: graphite: bicarbonate = 1000:3-30:1-50; for example, it can be but not limited to 1000:3:1, 1000:7:1, 1000:10:1, 1000:14:1, 1000:18:1, 1000:22:1, 1000:26:1, 1000:30:1, 1000:3:5, 1000:3:10, 1000:3:15, 1000:3:20, 1000:3:25, 1000:3:30, 1000:3:35, 1000:3:40, 1000:3:45, 1000:3:50; preferably, it is 1000:10-20:10-30.

[0038] In the present disclosure, the content of graphite and bicarbonate will affect the grinding process of aluminum slag. If the content of graphite is too low, the temperature of aluminum slag grinding will be high, affecting production safety; if the content of graphite is too high, the aluminum powder will contain a large amount of graphite, and the purity of the aluminum powder will decrease; if the content of bicarbonate is too low, the carbon dioxide generated by the system will be reduced, and the temperature during the aluminum slag grinding process will be too high, affecting system safety; if the content of bicarbonate is too high, the water content during the grinding process will increase, causing aluminum and water to react, affecting the safety of the grinding system.

[0039] In some embodiments, the bicarbonate is at least one of sodium bicarbonate, magnesium bicarbonate, calcium bicarbonate, potassium bicarbonate, and barium bicarbonate.

[0040] In the present disclosure, the above-mentioned bicarbonates can all be decomposed at 300° C., and the raw materials are relatively abundant and the operating cost is low.

[0041] In some embodiments, the mesh size of the sieving screen is 100-400 mesh, for example, but not limited to 100 mesh, 120 mesh, 150 mesh, 200 mesh, 250 mesh, 300 mesh, and 400 mesh.

[0042] By utilizing the particle size of the material to separate the third mixture after air separation, using a circular vibrating screen for screening, and controlling the mesh size and number of times of the screen, the aluminum powder and battery black powder can be separated, the battery black powder content in the aluminum powder can be reduced, and the purity of the aluminum powder can be improved, which is beneficial for subsequent utilization.

[0043] In some embodiments, the feed rate of the grinder is 100-1000 kg / h, for example, but not limited to, 100 kg / h, 200 kg / h, 300 kg / h, 400 kg / h, 500 kg / h, 600 kg / h, 700 kg / h, 800 kg / h, 900 kg / h, and 1000 kg / h. The feed rate of the grinder affects the quality of the aluminum powder and graphite. A large feed rate increases the content of graphite and battery black powder in the aluminum powder, resulting in a decrease in the purity of the aluminum powder. Excessive feed rate also increases heat generation, affecting system stability.

[0044] In some embodiments, the frequency of the grinder is 15-50 Hz, for example, but not limited to, 15 Hz, 20 Hz, 25 Hz, 30 Hz, 35 Hz, 40 Hz, 45 Hz, and 50 Hz.

[0045] In some embodiments, the mixing speed is 300-500 r / min, for example, but not limited to 300 r / min, 320 r / min, 350 r / min, 400 r / min, 450 r / min, 480 r / min, and 500 r / min.

[0046] In some embodiments, the mixing time is 30-60 min, for example, but not limited to, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, and 60 min.

[0047] On the other hand, the present disclosure provides aluminum powder obtained by the aluminum slag processing method.

[0048] On the other hand, the present disclosure provides the use of the aluminum powder in the preparation of fireworks and firecrackers.

[0049] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0050] In the following embodiments, the aluminum slag is the aluminum slag generated in the process of recycling waste lithium batteries, and the graphite is the graphite obtained in the process of recycling waste lithium batteries.

[0051] Example 1

[0052] This embodiment provides a method for treating aluminum slag, comprising the following steps:

[0053] (1) mixing aluminum slag, graphite, and barium bicarbonate at a mass ratio of 1000:3:1 at a speed of 500 r / min for 30 minutes to obtain a first mixture;

[0054] (2) adding the first mixture to a grinder at a temperature of 25° C., under nitrogen protection, and at a feeding rate of 100 kg / h, and grinding at a frequency of 15 Hz to obtain a second mixture;

[0055] (3) transporting the second mixture to a cyclone separator for air separation, collecting the first graphite in a bag dust collector, and returning the collected first graphite to the mixing step of step (1) for reuse; collecting the third mixture in a cyclone dust collector;

[0056] (4) The third mixture was sieved through a 120-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# battery black powder.

[0057] Example 2

[0058] This embodiment provides a method for treating aluminum slag, comprising the following steps:

[0059] (1) mixing aluminum slag, graphite, and magnesium bicarbonate in a mass ratio of 1000:15:15 at a speed of 400 r / min for 45 minutes to obtain a first mixture;

[0060] (2) adding the first mixture to a grinder at a temperature of 25° C., under nitrogen protection, and at a feeding rate of 350 kg / h, and grinding at a frequency of 35 Hz to obtain a second mixture;

[0061] (3) transporting the second mixture to a cyclone separator for air separation, collecting the first graphite in a bag dust collector, and returning the collected first graphite to the mixing step of step (1) for reuse; collecting the third mixture in a cyclone dust collector;

[0062] (4) The third mixture was sieved through a 150-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# battery black powder.

[0063] Example 3

[0064] This embodiment provides a method for treating aluminum slag, comprising the following steps:

[0065] (1) mixing aluminum slag, graphite, and sodium bicarbonate in a mass ratio of 1000:30:50 at a speed of 300 r / min for 60 min to obtain a first mixture;

[0066] (2) adding the first mixture to a grinder at a temperature of 25° C., under nitrogen protection, and at a feeding rate of 1000 kg / h, and grinding at a frequency of 50 Hz to obtain a second mixture;

[0067] (3) transporting the second mixture to a cyclone separator for air separation, collecting the first graphite in a bag dust collector, and returning the collected first graphite to the mixing step of step (1) for reuse; collecting the third mixture in a cyclone dust collector;

[0068] (4) The third mixture was sieved through a 150-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# battery black powder.

[0069] Example 4

[0070] This embodiment provides a method for treating aluminum slag, which differs from Example 3 only in that the mass ratio of aluminum slag, graphite, and sodium bicarbonate in step (1) is different. In this embodiment, the mass ratio of aluminum slag, graphite, and sodium bicarbonate is aluminum slag: graphite: sodium bicarbonate = 1000:10:30.

[0071] Example 5

[0072] This embodiment provides a method for treating aluminum slag, which differs from Example 3 only in that the mass ratio of aluminum slag, graphite, and sodium bicarbonate in step (1) is different. In this embodiment, the mass ratio of aluminum slag, graphite, and sodium bicarbonate is aluminum slag: graphite: sodium bicarbonate = 1000:20:20.

[0073] Example 6

[0074] This embodiment provides a method for treating aluminum slag, which differs from Example 3 only in that the mass ratio of aluminum slag, graphite, and sodium bicarbonate in step (1) is different. In this embodiment, the mass ratio of aluminum slag, graphite, and sodium bicarbonate is aluminum slag: graphite: sodium bicarbonate = 1000:10:10.

[0075] Comparative Example 1

[0076] This comparative example provides a method for treating aluminum slag, comprising the following steps:

[0077] (1) mixing aluminum slag and sodium bicarbonate at a mass ratio of 1000:50 at a speed of 300 r / min for 60 min to obtain a first mixture;

[0078] (2) adding the first mixture to a grinder at a temperature of 25° C., under nitrogen protection, and at a feeding rate of 1000 kg / h, and grinding at a frequency of 50 Hz to obtain a second mixture;

[0079] (3) The second mixture was sieved through a 150-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# black powder.

[0080] Comparative Example 2

[0081] This comparative example provides a method for treating aluminum slag, comprising the following steps:

[0082] (1) mixing aluminum slag and graphite in a mass ratio of 1000:30 at a rotation speed of 300 r / min for 60 min to obtain a first mixture;

[0083] (2) adding the first mixture to a grinder at a temperature of 25° C., under nitrogen protection, and at a feeding rate of 1000 kg / h, and grinding at a frequency of 50 Hz to obtain a second mixture;

[0084] (3) transporting the second mixture to a cyclone separator for air separation, collecting the first graphite in a bag dust collector, and returning the collected first graphite to the mixing step of step (1) for reuse; collecting the third mixture in a cyclone dust collector;

[0085] (4) The third mixture was sieved through a 150-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# black powder.

[0086] Comparative Example 3

[0087] This comparative example provides a method for treating aluminum slag, comprising the following steps:

[0088] The aluminum slag was added to the grinder at a temperature of 25°C, nitrogen protection and a feeding rate of 1000 kg / h, and ground at a frequency of 50 Hz. The ground product was sieved through a 150-mesh circular vibrating sieve to obtain 2# aluminum powder and 1# black powder.

[0089] The aluminum slag and the aluminum powder No. 2 obtained in Example were tested by X-ray diffractometer. The results are as follows Figure 2 and Figure 3 As shown, Figure 2 is the XRD pattern of aluminum slag, Figure 3 The XRD pattern of the aluminum powder No. 2 obtained in Example 3 is shown in FIG. Figure 2-3 It can be seen that the main components of aluminum slag are Al, C, LiFePO4, and AlO(OH), and the main component of 2# aluminum powder is Al, and it contains a small amount of LiFePO4 and does not contain C. This shows that after the aluminum slag is treated by the treatment method disclosed in the present invention, the separation effect of aluminum slag and C is good, the purity of aluminum powder is high, and after grinding, the aluminum powder does not contain Al2O3, which shows that the aluminum activity of the obtained aluminum powder is high.

[0090] The temperature during the grinding process was monitored and the contents of the main components of the obtained product were detected. The results are shown in Table 1 below.

[0091] Table 1

[0092]

[0093]

[0094] As can be seen from Table 1, using the treatment method disclosed in the present invention to treat aluminum slag can not only reduce the temperature during the grinding process, but also improve the purity of aluminum powder, which is conducive to the recycling of aluminum powder.

[0095] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for treating aluminum slag, characterized in that: The following steps are involved: uniformly mixing aluminum slag, graphite and bicarbonate to obtain a first mixture, wherein the thermal decomposition temperature of the bicarbonate is ≤300° C.; Grinding the first mixture in a grinder under an inert gas to obtain a second mixture; The second mixture is air-selected and sieved to obtain aluminum powder, battery black powder and graphite, and the obtained graphite is returned to the mixing process.

2. The method for treating aluminum slag according to claim 1, wherein: The mass ratio of the aluminum slag, graphite and bicarbonate is aluminum slag:graphite:bicarbonate=1000:3-30:1-50.

3. The method for treating aluminum slag according to claim 2, wherein: The mass ratio of the aluminum slag, graphite and bicarbonate is aluminum slag:graphite:bicarbonate=1000:10-20:10-30.

4. The method for treating aluminum slag according to claim 1, wherein: The bicarbonate is at least one of sodium bicarbonate, magnesium bicarbonate, calcium bicarbonate, potassium bicarbonate, and barium bicarbonate.

5. The method for treating aluminum slag according to claim 1, wherein: The mesh number of the screening is 100-400 meshes.

6. The method for treating aluminum slag according to claim 1, wherein: The feed rate of the grinder is 100-1000 kg / h.

7. The method for treating aluminum slag according to claim 1, wherein: The frequency of the grinding mill is 15-50 Hz.

8. The method for treating aluminum slag according to claim 1, wherein: The mixing speed is 300-500 r / min; and / or the mixing time is 30-60 min.

Images