A method for safe disassembly and low-consumption sorting of all components of waste lithium batteries

Abstract

The present application relates to the technical field of recycling of waste lithium ion batteries, and particularly relates to a method for safe disassembly and low-consumption sorting of all components of waste lithium batteries. The present application provides a method for safe disassembly and low-consumption sorting of all components of waste lithium batteries, which realizes low-consumption and high-efficiency separation of electrolyte, shell, diaphragm, positive and negative electrode current collectors, positive electrode material and negative electrode material under the premise of guaranteeing safety and environmental protection from the root.

Description

Technical Field

[0001] This invention relates to the field of waste lithium-ion battery recycling technology, specifically to a method for the safe dismantling and low-consumption sorting of all components of waste lithium batteries. Background Technology

[0002] With the explosive growth of the new energy vehicle industry and the accelerated iteration of consumer electronics devices, the amount of scrapped lithium-ion batteries is increasing exponentially. According to industry statistics, the global total amount of scrapped lithium batteries is expected to exceed 1 million tons by 2027. These batteries are rich in high-value metals such as lithium, cobalt, nickel, and manganese, but also contain toxic and hazardous substances such as electrolytes and heavy metals. The efficient and safe recycling of scrapped lithium batteries has both strategic significance for resource recycling and environmental protection, and has become a global focus.

[0003] As a crucial step in waste lithium battery recycling, crushing, sorting, and pretreatment have largely achieved industrial application. The current mainstream process is "charged crushing - high-temperature pyrolysis - multi-stage sorting - tail gas incineration - flue gas treatment," with a waste lithium battery processing capacity exceeding 2 tons / hour. The charged crushing stage uses nitrogen protection. However, because nitrogen has a similar density to air and is not very effective at diluting oxygen, the crushing stage not only incurs additional costs due to air separation but also poses safety hazards such as combustion and explosion. The crushing, mixing, pyrolysis, and powdering stage uses electricity or natural gas as energy, carbonizing the separator and simultaneously separating the positive and negative electrode powders from the aluminum and copper foils, respectively. After pyrolysis, the powders are sieved, with the undersize material being approximately 30% black powder; the oversize material consists of the outer shell, copper foil, and aluminum foil, also containing a certain amount of black powder. The oversize material is then air-classified to remove the positive and negative electrode materials, resulting in the outer shell. The blown-out mixture is then further processed through airflow de-powdering, grinding, pulverizing, sieving, and gravity separation to separate the black powder, copper foil, and aluminum foil.

[0004] Existing sorting methods, such as the "stringing candied hawthorns" method, are lengthy and inefficient. Electrolytes and other substances are mixed in the pyrolysis flue gas before entering the combustion furnace for treatment. To prevent the risk of electrolyte explosion, more than five times the volume of combustion air is typically used to dilute the electrolyte below its explosive limit, resulting in excessive fuel consumption. Subsequently, large quantities of flue gas containing complex pollutants such as fluorides undergo defluorination, denitrification, and dioxin removal before meeting emission standards.

[0005] Although recycled lithium will inevitably meet the needs of new battery manufacturing, the shortcomings of existing lithium battery recycling technologies directly result in the cost of recycling waste lithium battery resources being 10-30% higher than that of lithium extraction from ore and 40-50% higher than that of lithium extraction from salt lakes. Overall, this limits the substitution of recycled lithium for ore lithium. This dilemma urgently needs technological innovation to break through and support the construction of a new industrial pattern for the recycling and sustainable development of lithium energy storage resources. Summary of the Invention

[0006] To address the problems of high safety risks, significant secondary pollution, high energy consumption, and low economic efficiency in existing technologies, this invention provides a method for the safe dismantling and low-consumption sorting of all components of waste lithium batteries. Under the premise of fundamentally ensuring safety and environmental protection, it achieves low-consumption and high-efficiency separation of all components, including electrolyte, shell, separator, positive and negative current collectors, positive electrode materials, and negative electrode materials.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for the safe dismantling and low-consumption sorting of all components of waste lithium batteries, comprising the following steps:

[0009] S1. After dismantling or shredding the waste lithium battery in white oil, the electrolyte and a mixture A containing white oil, shell, separator, positive electrode and negative electrode are separated.

[0010] S2. Compressed air is introduced into the mixture A in step S1 for dynamic separation. After the shell deposited at the bottom is separated from the mixture A, water is added for emulsification and separation to obtain the upper mixture B and the lower mixture C.

[0011] The mixture B consists of white oil, a separator, and a positive electrode sheet; the mixture C consists of water, negative electrode powder obtained after de-powdering the negative electrode sheet, and a negative electrode current collector.

[0012] S3. First, perform solid-liquid separation on the mixture B in step S2. After separating out the white oil, electrolyze and de-powder the mixture B in brine to obtain positive electrode powder and positive electrode current collector, while collecting the diaphragm floating on the brine.

[0013] S4. First, sieve the mixture C in step S2 to obtain the negative electrode current collector, and then separate the solid and liquid to obtain the negative electrode powder and water.

[0014] The existing process of dismantling waste lithium batteries releases flammable and explosive electrolytes, which will burn and explode upon contact with oxygen. The common practice is to use nitrogen as the environmental medium for dismantling lithium batteries. However, since nitrogen has a density very close to that of air, it is difficult to ensure that the air is completely purged. In industrial practice, fires and explosions occur frequently.

[0015] To improve the safety of dismantling waste lithium batteries, this invention uses white oil instead of nitrogen as the environmental medium for dismantling lithium batteries, achieving 100% oxygen isolation and eliminating the risk of fire and explosion at the source. Because the environmental medium is changed to white oil, oxygen is completely isolated, and the dismantling process does not need to worry about heat accumulation caused by excessive dismantling force or sparks generated by mechanical friction, thus significantly improving dismantling efficiency.

[0016] Furthermore, in this invention, the distribution of the outer shell, separator, positive electrode plate, and negative electrode plate in the white oil is more orderly. Specifically, the outer shell and negative electrode powder sink to the bottom, the positive electrode powder, positive electrode current collector, and separator float to the top, while the electrolyte is completely dissolved in the white oil.

[0017] Ultimately, this invention enables efficient separation and high recycling rates, allowing waste lithium batteries to be fully recycled in a safe environment.

[0018] Preferably, in step S1, the waste lithium battery is a charged or uncharged waste lithium battery.

[0019] Preferably, in S1, the volume ratio of white oil to waste lithium battery is (10-50):1.

[0020] Preferably, in step S2, the compressed air intake is 5-50 m³ / s. 3 / t of waste lithium batteries, the pressure of compressed air is 0.3~0.8Mpa.

[0021] Preferably, in step S2, during emulsification and separation, the amount of water added is 0.3 to 3 times the volume of the white oil.

[0022] Preferably, in step S2, the emulsification separation method is as follows: after adding water, the mixture is continuously agitated by compressed air for 1 to 10 minutes, and then allowed to stand for 5 to 15 minutes to separate into layers.

[0023] Preferably, the white oil separated in S3 can be reused in S1.

[0024] Preferably, in step S3, the brine is a sulfate solution with a concentration of 5–20 g / L. More preferably, the sulfate solution is a sodium sulfate solution or a potassium sulfate solution.

[0025] Preferably, in step S3, the electrolytic depulping method is as follows: stainless steel is used as the positive electrode, graphite is used as the negative electrode, the cell voltage is 0.6–1.0V, and the current density is 200–500A / m. 2 The electrolysis time is 10 to 30 minutes.

[0026] Preferably, the water separated from the solid-liquid mixture in S4 can be reused in S2.

[0027] Therefore, the present invention has the following beneficial effects:

[0028] (1) This invention uses white oil to dismantle waste lithium batteries without consuming a large amount of nitrogen for oxygen protection, thus eliminating the risk of combustion and explosion at the source.

[0029] (2) The present invention completes the sorting of waste lithium batteries in white oil, and achieves efficient separation of all components. The electrolyte and white oil are immiscible and significantly separated into layers. After the lower layer releases the electrolyte, it can be upgraded and utilized. This avoids the secondary pollution caused by the volatilization of electrolyte in traditional processes, and also avoids the risk of combustion and explosion and the burden of exhaust gas treatment caused by the incineration of electrolyte in traditional technology.

[0030] (3) In the white oil system of the present invention, the positive and negative electrodes of the waste lithium battery float and sink respectively due to their different specific gravities. After adding water as a separation aid, the floating and sinking become more obvious. It is more efficient and less costly than traditional wind separation and mechanical screening, and the separation is more thorough. The negative electrode current collector and negative electrode powder can be efficiently dissociated in the aqueous phase. The positive electrode current collector and positive electrode powder can be efficiently dissociated through electrolysis. The negative electrode current collector and positive electrode current collector are relatively intact. The positive electrode powder and negative electrode powder are also efficiently recovered. The energy consumption is greatly reduced compared with the high temperature pyrolysis technology commonly used in the industry. The positive electrode powder and negative electrode powder are completely separated and are no longer a mixture.

[0031] (4) The white oil used in this invention is non-toxic, harmless, has good stability, does not volatilize, does not burn, does not polymerize, is immiscible with water, and will not bring additional burden to the industrial system. Attached Figure Description

[0032] Figure 1 This is a flowchart of the process flow of the present invention. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1 The following disassembly and sorting work is completed as shown.

[0036] S1. Disassemble or shred the waste lithium battery in 20 times its volume of white oil to separate the electrolyte and a mixture A containing white oil, casing, separator, positive electrode and negative electrode.

[0037] S2. In step S1, compressed air at 0.6 MPa is introduced into mixture A for dynamic separation, with a compressed air volume of 10 m³. 3 / t of waste lithium batteries, after separating the outer shell deposited at the bottom from mixture A, continue to emulsify and separate with water. At this time, the volume ratio of water to white oil is 1:1. After continuous agitation for 5 minutes, let it stand for 10 minutes to complete the stratification. The separator and positive electrode sheet enter the upper oil phase (mixture B), while the negative electrode powder and copper foil obtained after de-powdering of the negative electrode sheet enter the lower aqueous phase (mixture C).

[0038] S3. First, perform solid-liquid separation on mixture B from step S2. After separating the white oil, electrolyze and de-powder mixture B in a 10 g / L sodium sulfate system for 20 min to obtain positive electrode powder and aluminum foil. Simultaneously, collect the diaphragm floating on the sodium sulfate brine. The electrolytic de-powdering conditions are: cell voltage 1.0 V, current density 250 A / m. 2 .

[0039] S4. First, the mixture C in step S2 is sieved to obtain copper foil, and then solid-liquid separation is performed to obtain negative electrode powder and water.

[0040] Ultimately, the recovery rates of the outer casing, positive electrode powder, aluminum foil, negative electrode powder, copper foil, separator, and electrolyte were 99.8%, 98.5%, 94.5%, 93.3%, 95.2%, 99.7%, and 98.7%, respectively.

[0041] Example 2

[0042] like Figure 1 The following disassembly and sorting work is completed as shown.

[0043] S1. Disassemble or shred the waste lithium battery in 30 times its volume of white oil to separate the electrolyte and a mixture A containing white oil, casing, separator, positive electrode and negative electrode.

[0044] S2. In step S1, 0.6 MPa compressed air is introduced into mixture A for dynamic separation. The volume of compressed air is 5 m³ / s. 3 / t of waste lithium batteries, after separating the outer shell deposited at the bottom from mixture A, continue to emulsify and separate with water. At this time, the volume ratio of water to white oil is 0.8:1. After continuous agitation for 3 minutes, let it stand for 5 minutes to complete the stratification. The separator and positive electrode sheet enter the upper oil phase (mixture B), while the negative electrode powder and copper foil obtained after de-powdering of the negative electrode sheet enter the lower aqueous phase (mixture C).

[0045] S3. First, perform solid-liquid separation on mixture B from step S2. After separating the white oil, electrolyze and de-powder mixture B in a 15 g / L potassium sulfate system for 20 min to obtain positive electrode powder and aluminum foil. Simultaneously, collect the diaphragm floating on the sodium sulfate brine. The electrolytic de-powdering conditions are: cell voltage 1.0 V, current density 350 A / m. 2 .

[0046] S4. First, the mixture C in step S2 is sieved to obtain copper foil, and then solid-liquid separation is performed to obtain negative electrode powder and water.

[0047] Ultimately, the recovery rates of the outer casing, positive electrode powder, aluminum foil, negative electrode powder, copper foil, separator, and electrolyte were 99.6%, 98.8%, 95.2%, 95.1%, 96.3%, 99.7%, and 98.8%, respectively.

[0048] Example 3

[0049] like Figure 1 The following disassembly and sorting work is completed as shown.

[0050] S1. Disassemble or shred the waste lithium battery in 30 times its volume of white oil to separate the electrolyte and a mixture A containing white oil, casing, separator, positive electrode and negative electrode.

[0051] S2. In step S1, 0.6 MPa compressed air is introduced into mixture A for dynamic separation, with a compressed air volume of 15 m³. 3 / t of waste lithium batteries, after separating the outer shell deposited at the bottom from mixture A, continue to emulsify and separate with water. At this time, the volume ratio of water to white oil is 1.5:1. After continuous agitation for 3 minutes, let it stand for 10 minutes to complete the stratification. The separator and positive electrode sheet enter the upper oil phase (mixture B), while the negative electrode powder and copper foil obtained after de-powdering of the negative electrode sheet enter the lower aqueous phase (mixture C).

[0052] S3. First, perform solid-liquid separation on mixture B from step S2. After separating the white oil, electrolyze and de-powder mixture B in a 10 g / L sodium sulfate system for 20 min to obtain positive electrode powder and aluminum foil. Simultaneously, collect the diaphragm floating on the sodium sulfate brine. The electrolytic de-powdering conditions are: cell voltage 1.0 V, current density 300 A / m³. 2 .

[0053] S4. First, the mixture C in step S2 is sieved to obtain copper foil, and then solid-liquid separation is performed to obtain negative electrode powder and water.

[0054] Ultimately, the recovery rates of the outer casing, positive electrode powder, aluminum foil, negative electrode powder, copper foil, separator, and electrolyte were 99.6%, 99.3%, 95.6%, 94.7%, 96.1%, 99.8%, and 98.6%, respectively.

Claims

1. A method for the safe dismantling and low-consumption sorting of all components of waste lithium batteries, characterized in that, Includes the following steps: S1. After dismantling or shredding the waste lithium battery in white oil, the electrolyte and a mixture A containing white oil, shell, separator, positive electrode and negative electrode are separated. S2. Compressed air is introduced into the mixture A in step S1 for dynamic separation. After the shell deposited at the bottom is separated from the mixture A, water is added for emulsification and separation to obtain the upper mixture B and the lower mixture C. The mixture B consists of white oil, a separator, and a positive electrode sheet; the mixture C consists of water, negative electrode powder obtained after de-powdering the negative electrode sheet, and a negative electrode current collector. S3. First, perform solid-liquid separation on the mixture B in step S2. After separating out the white oil, electrolyze and de-powder the mixture B in brine to obtain positive electrode powder and positive electrode current collector, while collecting the diaphragm floating on the brine. S4. First, sieve the mixture C in step S2 to obtain the negative electrode current collector, and then separate the solid and liquid to obtain the negative electrode powder and water.

2. The method as described in claim 1, characterized in that, In S1, the waste lithium battery can be a charged or uncharged waste lithium battery.

3. The method as described in claim 1 or 2, characterized in that, In S1, the volume ratio of white oil to waste lithium battery is (10-50):

1.

4. The method as described in claim 1, characterized in that, In step S2, the compressed air intake is 5–50 m³ / s. 3 / t of waste lithium batteries, the pressure of compressed air is 0.3~0.8Mpa.

5. The method as described in claim 1, characterized in that, In step S2, during emulsification and separation, the amount of water added is 0.3 to 3 times the volume of the white oil.

6. The method as described in claim 1 or 5, characterized in that, In S2, the emulsification separation method is as follows: after adding water, the mixture is continuously agitated by compressed air for 1 to 10 minutes, and then allowed to stand for 5 to 15 minutes to separate into layers.

7. The method as described in claim 1, characterized in that, The white oil separated in S3 can be reused in S1.

8. The method as described in claim 1, characterized in that, In S3, the brine is a sulfate solution with a concentration of 5–20 g / L.

9. The method as described in claim 1 or 8, characterized in that, In step S3, the electrolytic depulping method is as follows: stainless steel is used as the positive electrode, graphite is used as the negative electrode, the cell voltage is 0.6–1.0V, and the current density is 200–500A / m. 2 The electrolysis time is 10 to 30 minutes.

10. The method as described in claim 1, characterized in that, The water separated from the solid-liquid mixture in S4 can be reused in S2.

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