Recycling process for extracting copper from waste lithium battery electrode graphite powder

Abstract

The invention relates to the technical field of lithium battery recovery, and particularly discloses a recovery process for extracting copper from waste lithium battery electrode graphite powder, which comprises the following steps: step 1, carrying out insulation treatment on a waste lithium battery, and then conveying the waste lithium battery to a battery negative electrode dismounting system; a battery negative electrode is detached through the battery negative electrode detaching system, the detached negative electrode is fed into the crushing and grinding system to be crushed and ground and then screened through the wet screening system, graphite powder and copper powder enter an aqueous solution mixed with a flotation agent, and after standing for a period of time, the graphite powder and the copper powder are separated from each other due to different densities of the graphite powder and the copper powder. According to the method, graphite powder and copper powder are separated, then the copper powder is heated and poured into copper foil, copper extraction is achieved, in the process, the graphite powder does not need to be raised, therefore, the graphite powder is not prone to being attached to electronic components, and meanwhile in the process of extracting copper through the method, the used components are low in power requirement and low in noise.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery recycling, and in particular relates to a recycling process for extracting copper from graphite powder of waste lithium battery electrodes. Background Art

[0002] Lithium batteries are a type of battery that uses lithium metal or lithium alloy as positive / negative electrode materials and a non-aqueous electrolyte solution.

[0003] Waste battery recycling refers to the reuse of used batteries through recycling. The most commonly used industrial battery in China is lead-acid batteries, and lead accounts for more than 50% of the total cost of batteries. The main technologies used are pyrometallurgical processes, hydrometallurgical processes, and solid-phase electrolytic reduction. The outer shell is plastic, which can be recycled and basically achieves no secondary pollution. Graphite is used as the raw material for the negative electrode of lithium batteries.

[0004] At present, the main methods for screening copper powder from graphite powder in batteries are: dry screening or wind-force air separation. During the use of this process, the negative electrode powder, i.e., graphite powder, will produce dust. The dust is easy to adhere to the electrical components of the surrounding equipment, posing safety hazards such as electrical short circuits and spontaneous combustion. In addition, when the above method is applied on site, the air environment and noise have a great impact. Therefore, this application proposes a recovery process for extracting copper from graphite powder of waste lithium battery electrodes. Summary of the invention

[0005] The purpose of the present invention is to provide a recovery process for extracting copper from graphite powder of waste lithium battery electrodes to solve the problems raised by the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a recovery process for extracting copper from graphite powder of waste lithium battery electrodes, comprising the following steps:

[0007] Step 1: Insulate the used lithium batteries and send them to the battery negative electrode disassembly system;

[0008] Step 2: The battery negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system;

[0009] Step 3: The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder;

[0010] Step 4: Pour the copper-containing graphite powder obtained in the above step 3 into a wet screening system, in which a screening liquid is added, and after the copper-containing graphite powder is allowed to stand in the above screening liquid for a period of time, the graphite powder and the copper powder are at different liquid level heights of the screening liquid due to their different densities, and the separated graphite powder and copper powder are taken out respectively;

[0011] Step 5: Heat and melt the copper powder obtained in the above step 4 to form copper liquid, which is then fed into a forming system to form copper foil.

[0012] Preferably, the method for removing the negative electrode from the waste lithium battery mentioned in step 2 is: unfasten the double fixing buckle on the waste lithium battery, find and remove the fastening nut on the waste lithium battery, pry open the fastening block at the negative electrode of the waste lithium battery, and take out the negative electrode, that is, the copper-containing graphite rod.

[0013] Preferably, the method for removing the negative electrode from the waste lithium battery mentioned in step 2 is: using a robot to cut one end of the negative electrode of the lithium battery using pliers, manually unscrewing the fastening block and other components at the negative electrode using pliers, and then taking out the negative electrode.

[0014] Preferably, the waste lithium batteries with negative electrodes removed by the battery negative electrode disassembly system are sent to the crushing system, crushed by the crushing system and sent to the floating screening system. The crushed waste lithium batteries enter the water in the floating screening system, and the outer shell and the positive electrode powder therein are at different liquid level heights due to their different densities, and are screened out and taken out separately.

[0015] Preferably, the screening liquid mentioned in step 4 is an aqueous solution mixed with a flotation agent, and the copper-containing graphite powder is allowed to stand in the screening liquid for 2-3 minutes.

[0016] Preferably, the copper powder obtained in step 4 is first transported to a drying system before being heated and melted, and is dried by the drying system.

[0017] A recycling process for extracting copper from graphite powder of waste lithium battery electrodes, comprising the following steps:

[0018] Step 1): After the waste lithium battery is insulated, it is sent to the battery negative electrode disassembly system;

[0019] Step 2): The battery negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system;

[0020] Step 3): The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder;

[0021] Step 4): The copper-containing graphite powder obtained in the above step 3) is sent to a vibration screening system, which performs vibration screening on the copper-containing graphite powder, and the larger particles inside the copper-containing graphite powder are sent back to the crushing and grinding system for crushing and grinding again, and then enter the vibration screening system again, and the powder with particles that meet the requirements is sent to the specific gravity sorting system;

[0022] Step 5): The specific gravity sorting system uses the density difference of the materials to sort out the graphite powder and copper powder;

[0023] Step 6): The copper powder obtained in the above step 5) is heated and melted to form copper liquid, which is then fed into a molding system.

[0024] Preferably, the gravity separation system in step 5) includes a gravity separator, which adjusts the parameter values ​​of wind pressure and amplitude to cause mutual displacement and stratification between materials, thereby separating graphite powder and copper powder of different densities.

[0025] Preferably, the forming system in step 6) includes a mold, and the copper liquid is fed into the cavity of the mold from the feed port of the mold. After the copper liquid is cooled, copper foil is formed under the action of the mold. The detachable upper mold in the mold is opened to take the copper foil out of the mold.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention removes the negative electrode of the battery through the battery negative electrode removal system, sends the removed negative electrode into the crushing and grinding system for crushing and grinding, and then screens it through the wet screening system. The graphite powder and copper powder enter the aqueous solution mixed with the flotation agent. After standing for a period of time, the graphite powder and the copper powder are distinguished due to the different densities of the two. Then, the copper powder is heated and cast into copper foil to achieve copper extraction. During the process, the graphite powder does not need to be lifted, so it is not easy to adhere to the electronic components. At the same time, in the process of extracting copper by the above method, the power requirements of the components used are not large and the noise is also small.

[0028] 2. The present invention The present invention removes the negative electrode of the battery through the battery negative electrode removal system, and sends the removed negative electrode into the crushing and grinding system for crushing and grinding. The graphite powder and copper powder therein can be screened out by two methods. The larger particles in the copper-containing graphite powder are sent back into the crushing and grinding system through the vibration screening system to make the powder particles in the copper-containing graphite powder roughly the same size. Then the copper-containing graphite powder passes through the specific gravity sorting system. The specific gravity separator in the specific gravity sorting system adjusts technical parameters such as wind pressure and amplitude to make the materials mutually replaced and stratified. The material with higher density settles slower in the airflow, while the material with lower density settles faster in the airflow, thereby separating the graphite powder from the copper powder. In the above-mentioned physical separation process, the vibration screening system only serves to accelerate the falling speed of small particles, so its speed is not fast, the noise is small, and the graphite powder will not be scattered into the air. The screening process of copper powder and graphite powder is inside the specific gravity separator, and no dust directly entering the surrounding air is generated. The device is closed, so its noise is also small.

[0029] 3. After the negative electrode of the battery of the present invention is disassembled, the remaining shell and positive electrode are crushed by the crushing system and then sent to the water in the floating screening system. Since the shell and the positive electrode powder are made of different materials and have different densities, the liquid level heights of the positive electrode and the shell in the water are different. Therefore, the shell and the positive electrode powder are screened to facilitate subsequent classification and processing. This part of the material can be reused to reduce the waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of Embodiment 1 of the present invention.

[0031] Figure 2 This is a flow chart of Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1:

[0034] Reference Figure 1 A recycling process for extracting copper from graphite powder of waste lithium battery electrodes comprises the following steps:

[0035] Step 1: After the waste lithium battery is insulated, it is sent to the battery negative electrode disassembly system. The battery negative electrode disassembly system can be disassembled by full manual or semi-manual methods. The full manual disassembly process is as follows: first, unfasten the double fixing buckle on the waste lithium battery, then find and remove the fastening nut on the waste lithium battery, and then pry open the fastening block at the negative electrode of the waste lithium battery to take out the negative electrode, that is, the copper-containing graphite rod; it can also be disassembled in a semi-mechanical and slightly violent way. The specific disassembly process is as follows: first, use a robot to use pliers to cut one end of the negative electrode of the lithium battery, and then manually use pliers to unscrew the fastening block and other components at the negative electrode, and then take out the negative electrode;

[0036] Step 2: The negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system. At the same time, the waste lithium battery with the negative electrode removed is sent to the crushing system, crushed by the crushing system and sent to the floating screening system. The crushed waste lithium battery enters the water in the floating screening system. The outer shell and the positive electrode powder inside are at different liquid levels due to different densities, so they are screened out and taken out separately;

[0037] Step 3: The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder;

[0038] Step 4: pour the copper-containing graphite powder obtained above into a wet screening system, a screening liquid is added into the wet screening system, and the screening liquid is an aqueous solution mixed with a flotation agent. After the copper-containing graphite powder is allowed to stand in the screening liquid for a period of time, the copper-containing graphite powder is allowed to stand in the screening liquid for 2-3 minutes. The graphite powder and the copper powder are at different liquid level heights of the screening liquid due to their different densities, and the separated graphite powder and copper powder are taken out respectively;

[0039] Step 5: Heat and melt the copper powder obtained in the above step to form copper liquid and feed it into a molding system. The molding system includes a mold. The above copper liquid is fed into the cavity in the mold from the feed port of the mold. After the copper liquid is cooled, copper foil is formed under the action of the mold. The detachable upper mold in the mold is opened to take the copper foil out of the mold. It should be noted that the copper powder obtained in step 4 is first transported to a drying system before being heated and melted, and is dried by the drying system. This step is to dry the copper powder. This is because the temperature of the heating and melting step is relatively high, and the copper powder mixed with the screening liquid is directly heated and melted, which makes a loud noise and produces high-temperature water vapor. The escape of high-temperature water vapor will scald surrounding personnel or cause overheating of equipment in contact with it.

[0040] Embodiment 2:

[0041] Reference Figure 2 A recycling process for extracting copper from graphite powder of waste lithium battery electrodes comprises the following steps:

[0042] Step 1): After the waste lithium battery is insulated, it is sent to the battery negative electrode disassembly system. The battery negative electrode disassembly system can be disassembled in a fully manual or semi-manual manner. The fully manual specific disassembly process is as follows: first, unfasten the double fixing buckle on the waste lithium battery, then find and remove the fastening nut on the waste lithium battery, and then pry open the fastening block at the negative electrode of the waste lithium battery to take out the negative electrode, that is, the copper-containing graphite rod; it can also be disassembled in a semi-mechanical and slightly violent manner. The specific disassembly process is as follows: first, use a robot to use pliers to cut one end of the negative electrode of the lithium battery, then manually use pliers to unscrew the fastening block and other components at the negative electrode, and then take out the negative electrode;

[0043] Step 2): The negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system. At the same time, the waste lithium battery with the negative electrode removed is sent to the crushing system, crushed by the crushing system and sent to the floating screening system. The crushed waste lithium battery enters the water in the floating screening system. The outer shell and the positive electrode powder inside are at different liquid levels due to different densities, so they are screened out and taken out separately;

[0044] Step 3): The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder;

[0045] Step 4): The copper-containing graphite powder obtained in the above step is sent to the vibration screening system, and the larger particles therein are sent back to the crushing and grinding system for crushing and grinding again, and then enter the vibration screening system again, and the powder with particles meeting the requirements is sent to the specific gravity sorting system;

[0046] Step 5): The specific gravity sorting system includes a specific gravity sorting machine, which uses the density difference of the materials for sorting to screen out the graphite powder and the copper powder. Specifically, the specific gravity sorting machine adjusts the technical parameters, such as wind pressure and amplitude, so that the materials are mutually replaced to produce stratification. The material with higher density settles more slowly in the airflow, while the material with lower density settles more quickly in the airflow, thereby separating the materials with different densities;

[0047] Step 6): The copper powder obtained in the above step is heated and melted to form copper liquid and is fed into a molding system, the molding system includes a mold, the copper liquid is fed into the cavity of the mold from the feed port of the mold, after the copper liquid is cooled, it forms copper foil under the action of the mold, the detachable upper mold in the mold is opened, and the copper foil is taken out from the mold.

[0048] Working principle:

[0049] To extract and recycle the copper at the negative electrode of the waste lithium battery, the negative electrode of the battery must first be removed by the battery negative electrode removal system. After the negative electrode is removed, the remaining lithium battery is processed by the crushing system and the floating screening system to separate the shell and the positive electrode powder, which is convenient for subsequent classification and recycling;

[0050] After the negative electrode of the dismantled waste lithium battery enters the crushing and grinding system for crushing and grinding, the graphite powder and copper powder therein can be separated by two methods. One method is to separate the graphite powder and copper powder therein through a wet screening system to extract copper; the other method is to send the larger particles in the copper-containing graphite powder back into the crushing and grinding system through a vibration screening system to make the powder particles in the copper-containing graphite powder roughly the same size, and then the copper-containing graphite powder is separated from the graphite powder through a specific gravity sorting system;

[0051] Afterwards, the copper powder is heated, melted and cast into copper foil for subsequent reuse.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for recovering copper from graphite powder of waste lithium battery electrodes, characterized in that: The following steps are involved: Step 1: Insulate the used lithium batteries and send them to the battery negative electrode disassembly system; Step 2: The battery negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system; Step 3: The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder; Step 4: Pour the copper-containing graphite powder obtained in the above step 3 into a wet screening system, in which a screening liquid is added, and after the copper-containing graphite powder is allowed to stand in the above screening liquid for a period of time, the graphite powder and the copper powder are at different liquid level heights of the screening liquid due to their different densities, and the separated graphite powder and copper powder are taken out respectively; Step 5: Heat and melt the copper powder obtained in the above step 4 to form copper liquid, which is then fed into a forming system to form copper foil.

2. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 1, characterized in that: The method for removing the negative electrode from the used lithium battery mentioned in step 2 is: unfasten the double fixing buckles on the used lithium battery, find and remove the fastening nuts on the used lithium battery, pry open the fastening block at the negative electrode of the used lithium battery, and take out the negative electrode, that is, the copper-containing graphite rod.

3. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 1, characterized in that: The method for removing the negative electrode from the waste lithium battery mentioned in step 2 is: use a robot to cut one end of the negative electrode of the lithium battery using pliers, manually unscrew the fastening block and other components at the negative electrode using pliers, and then take out the negative electrode.

4. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 2 or 3, characterized in that: The waste lithium batteries with the negative electrodes removed by the battery negative electrode disassembly system are sent to the crushing system, and then crushed by the crushing system and sent to the floating screening system. The crushed waste lithium batteries enter the water in the floating screening system, and the outer shell and the positive electrode powder inside are at different liquid levels due to their different densities, so they are screened out and taken out separately.

5. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 1, characterized in that: The screening liquid mentioned in step 4 is an aqueous solution mixed with a flotation agent, and the copper-containing graphite powder is allowed to stand in the screening liquid for 2-3 minutes.

6. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 1, characterized in that: The copper powder obtained in step 4 is first transported to a drying system before being heated and melted, and then dried by the drying system.

7. A process for recovering copper from graphite powder of waste lithium battery electrodes, characterized in that: The following steps are involved: Step 1): After the waste lithium battery is insulated, it is sent to the battery negative electrode disassembly system; Step 2): The battery negative electrode disassembly system removes the negative electrode from the waste lithium battery and sends it to the crushing and grinding system; Step 3): The copper-containing graphite rods entering the crushing and grinding system are crushed and ground to form copper-containing graphite powder; Step 4): The copper-containing graphite powder obtained in the above step 3) is sent to a vibration screening system, which performs vibration screening on the copper-containing graphite powder, and the larger particles inside the copper-containing graphite powder are sent back to the crushing and grinding system for crushing and grinding again, and then enter the vibration screening system again, and the powder with particles that meet the requirements is sent to the specific gravity sorting system; Step 5): The specific gravity sorting system uses the density difference of the materials to sort out the graphite powder and copper powder; Step 6): The copper powder obtained in the above step 5) is heated and melted to form copper liquid, which is then fed into a molding system.

8. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 7, characterized in that: The gravity separation system in step 5) includes a gravity separator, which adjusts the parameter values ​​of wind pressure and amplitude to cause mutual displacement and stratification between materials, thereby separating graphite powder and copper powder of different densities.

9. A process for recovering copper from graphite powder of waste lithium battery electrodes according to claim 8, characterized in that: The forming system in step 6) includes a mold. The copper liquid is fed into the cavity of the mold from the feed port of the mold. After the copper liquid is cooled, it forms copper foil under the action of the mold. The detachable upper mold in the mold is opened to take the copper foil out of the mold.

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