Method for resourceful treatment of waste lithium batteries based on thermal radiation

Abstract

The application discloses a kind of based on heat radiation resourceful treatment waste lithium battery method, it is related to waste battery recycling technical field, steps are as follows: the waste lithium battery of recycling is pyrolyzed so that electrolyte is evaporated, and after waste lithium battery cooling, disassembly is carried out, copper shell, aluminum shell, positive electrode material and negative electrode material are obtained;Positive electrode material, negative electrode material are crushed, screening, and copper, iron, aluminum material obtained, and the remaining material is separated three times, first separation obtains graphite, second separation obtains iron carbonate, third separation obtains lithium carbonate and sodium chloride.The application can make waste lithium iron phosphate battery not need to discharge when processing, all materials in waste lithium battery are resource utilization, and the processing process is safe.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste battery recycling, in particular to a method for resourceful treatment of waste lithium batteries based on heat radiation, especially for resourceful treatment of waste lithium iron phosphate batteries. BACKGROUND

[0002] Lithium iron phosphate batteries have the characteristics of small size and light weight. The volume of lithium iron phosphate batteries of the same specification capacity is 1 / 3 of that of lead-acid batteries, and the weight is 1 / 3 of that of lead-acid batteries. Therefore, they are widely used in large electric vehicles, light electric vehicles, and energy storage devices for solar (or wind) power generation.

[0003] One lithium iron phosphate battery has a cycle life of 3000 times. When the battery exceeds 3000 times, it will be retired. In recent years, in order to achieve the goal of 30 carbon peak and 60 carbon neutral, China has vigorously developed new energy industry, and therefore a large number of lithium batteries have been produced, of which lithium iron phosphate batteries account for 46.3%. When lithium iron phosphate batteries reach the retirement age, a large number of waste lithium iron phosphate batteries will be generated.

[0004] Waste lithium iron phosphate batteries contain a large amount of copper, aluminum, lithium, iron and other metals, which have resource recycling value. The electrolyte, positive and negative electrode materials in the waste lithium iron phosphate batteries also have high-grade recycling value. At present, before the disposal of waste lithium batteries, they need to be discharged and then disassembled and crushed. If they are directly disassembled, lithium batteries may explode and cause fire, and this recycling method also makes lithium batteries unable to be recycled to the maximum extent.

[0005] Therefore, there is an urgent need in the market for a waste lithium battery treatment method with high cost performance, safe treatment, and high resource utilization. SUMMARY

[0006] The purpose of the present application is to provide a method for resourceful treatment of waste lithium batteries based on heat radiation, so that waste lithium iron phosphate batteries do not need to be discharged during treatment, all materials in the waste lithium batteries are utilized for resource utilization, and the treatment process is safe.

[0007] To achieve the purpose of the present application, the technical scheme adopted is as follows: a method for resourceful treatment of waste lithium batteries based on heat radiation, the steps are as follows:

[0008] The recovered waste lithium batteries are pyrolyzed to evaporate the electrolyte, and after the waste lithium batteries are cooled, they are disassembled to obtain copper shells, aluminum shells, positive electrode materials and negative electrode materials;

[0009] The positive electrode materials and negative electrode materials are crushed and screened to obtain copper, iron and aluminum substances, and the remaining substances are separated three times to obtain graphite in the first separation, iron carbonate in the second separation, and lithium carbonate and sodium chloride in the third separation.

[0010] Further, the pyrolysis temperature of the waste lithium battery is 400-600 DEG C, and the pyrolysis time is 30-70 min.

[0011] Further, the waste lithium battery generates pyrolysis gas in the pyrolysis process, and the pyrolysis gas includes ethylene and propylene generated by the heat cracking of the separator PE or the separator PP in the waste lithium battery, HF, vinylidene fluoride, 1,2,3-trifluorobenzene and 1,2-difluorobenzene generated by the heat cracking of the binder PVDF of the positive and negative electrodes in the waste lithium battery, and electrolyte vapor generated when the electrolyte is evaporated.

[0012] Further, the pyrolysis gas generated in the pyrolysis process of the waste lithium battery is condensed to obtain an oil containing ethyl acetate, propylene carbonate and alkanes, alkenes and ketones.

[0013] Further, the non-condensable gas after condensation of the pyrolysis gas is reacted with a sodium hydroxide solution to remove HF in the non-condensable gas.

[0014] Further, the salt generated by the reaction of the non-condensable gas with the sodium hydroxide solution is crystallized, and the deacidified non-condensable gas is dehydrated, and the dehydrated non-condensable gas is used as fuel.

[0015] Further, the temperature of the cooled waste lithium battery is lower than 50 DEG C.

[0016] Further, the particle size of the positive material and the negative material after crushing is less than 1 mm.

[0017] Further, the first separation is: the remaining material is sent into water, and hydrochloric acid is added, and the PH in the first separation process is 1.5-2.5, the temperature is 30-45 DEG C, and the reaction time is 20-40 min.

[0018] Further, the second separation is: water, sodium hydroxide and hydrogen peroxide are added to the solution after the first separation, and the PH in the second separation process is 4.2-5.6, the temperature is 85-95 DEG C, and the reaction time is 40-60 min.

[0019] Further, the third separation is: sodium carbonate is added to the solution after the second separation, and the PH in the third separation process is 11-12, and the reaction time is 30-50 min.

[0020] Further, the remaining solution after the third separation is crystallized.

[0021] A system for resourceful treatment of waste lithium batteries based on thermal radiation, comprising a thermal radiation treatment unit, a cooling and splitting and crushing and sorting unit, and a resource recovery unit arranged in sequence.

[0022] The heat radiation treatment unit comprises a heat radiation reactor, wherein a feeding area, a pyrolysis area and a discharging area are sequentially arranged in a conveying direction inside the heat radiation reactor;

[0023] The cooling, disassembling, crushing and sorting unit comprises a cooling tunnel kiln, a manual disassembling unit, a crusher and a flotation device which are sequentially arranged in the conveying direction;

[0024] The resource recovery unit comprises a lithium iron phosphate separation tank, a filter press I, an iron removal tank, a filter press II, a lithium carbonate reaction tank and a filter press III which are sequentially arranged in the conveying direction.

[0025] Further, the heat radiation reactor comprises an inner cavity and an outer cavity, the feeding area, the pyrolysis area and the discharging area are located in the inner cavity, and the outer cavity is wrapped around the periphery of the pyrolysis area.

[0026] Further, the feeding area, the pyrolysis area and the discharging area are each provided with a conveying belt, the three conveying belts are sequentially connected, and hydraulic cut-off valves are arranged at both ends of the inner cavity, between the feeding area and the pyrolysis area, and between the pyrolysis area and the discharging area.

[0027] Further, the outer cavity is further provided with a flow guide plate, and the inner wall of the inner cavity is further provided with a flow guide column, and the flow guide column is located in the pyrolysis area.

[0028] Further, the heat radiation reactor further comprises a burner, and a combustion cylinder of the burner is in communication with a heat source inlet of the outer cavity.

[0029] Further, the heat radiation treatment unit further comprises a condenser, an oil recovery tank, a deacidification tower and a NaF crystallizer, a feeding inlet of the condenser is connected with a gas outlet of the pyrolysis area, a discharging outlet of the condenser is connected with the oil recovery tank, a gas outlet of the condenser is connected with a gas inlet of the deacidification tower, and a liquid outlet of the deacidification tower is connected with a feeding inlet of the NaF crystallizer.

[0030] Further, a heat source inlet of the NaF crystallizer is in communication with a heat source outlet of the outer cavity.

[0031] Further, the condenser is a U-tube heat exchanger, a tube sheet heat exchanger or a floating head heat exchanger.

[0032] Further, the heat radiation treatment unit further comprises a NaOH preparation tank, and a liquid outlet of the NaOH preparation tank is connected with a spraying structure in the deacidification tower.

[0033] Further, the heat radiation treatment unit further comprises a gas-liquid separator, and a gas outlet of the deacidification tower is connected with a gas inlet of the gas-liquid separator.

[0034] Further, the cooling tunnel kiln comprises an inner cavity and an outer cavity, the outer cavity is wrapped around the inner cavity, and a cooling medium inlet and a cooling medium outlet are arranged on the outer cavity.

[0035] Further, the water inlet of the lithium iron phosphate separation tank is connected with the outlet of the cooling medium.

[0036] Further, the water inlet of the iron removal tank is connected with the outlet of the heat exchange medium of the condenser.

[0037] Further, the resource recycling unit further comprises an evaporation crystallizer and a dryer, the feed inlet of the evaporation crystallizer is connected with the liquid outlet of the pressure filter III, the feed inlet of the dryer is connected with the solid outlet of the pressure filter III, and the gas outlet of the dryer is further connected with a flue gas treatment device.

[0038] The beneficial effects of the present application are:

[0039] 1. The original electrolyte salt solution in the waste lithium battery is discharged, crushed and pyrolyzed, and then disassembled and crushed, the organic matters such as binders in the high-temperature carbonized electrolyte are utilized, the electrolyte is precipitated in the crushing process in the traditional process, the incomplete discharge is effectively avoided to avoid the phenomenon of combustion and explosion, the production efficiency is improved, the safety of production is ensured, and the purity of the product is improved by adopting different chemical treatment processes for the disassembled positive and negative materials.

[0040] 2. The pyrolysis gas generated in the pyrolysis process is treated, and the evaporation gas of the electrolyte is completely harmless. BRIEF DESCRIPTION OF DRAWINGS

[0041] The accompanying drawings illustrate exemplary embodiments of the present application and, together with the general description of the application given above, and the detailed description of the embodiments given below, serve to explain the principles of the present application. These drawings are included herewith and constitute a part of this specification.

[0042] Figure 1 is a system diagram of the system for resourceful treatment of waste lithium batteries based on thermal radiation provided by the present application;

[0043] Figure 2 is a structural schematic diagram of the pyrolysis reactor;

[0044] Figure 3 is a side schematic diagram of the pyrolysis reactor;

[0045] Figure 4 is a schematic diagram of copper powder;

[0046] Figure 5 is a schematic diagram of aluminum powder;

[0047] Figure 6 is a schematic diagram of graphite;

[0048] Figure 7 is a schematic diagram of lithium carbonate powder.

[0049] The attached diagram shows the markings and corresponding component names:

[0050] 1-Pyrolysis reactor, 2-Condenser, 3-Oil recovery tank, 4-Deacidification tower, 5-NaOH preparation tank, 6-NaF crystallizer, 7-Gas-liquid separator, 8-Tunnel cooling kiln, 9-Manual dismantling unit, 10-Crusher, 11-Flotation equipment, 12-Lithium iron phosphate separation tank, 13-Filter press I, 14-Iron removal tank, 15-Filter press II, 16-Lithium carbonate reaction tank, 17-Dryer, 18-Evaporation crystallizer, 19-Flue gas treatment device, 20-Filter press III;

[0051] 101-Hydraulic shut-off valve, 102-Internal cavity, 103-External cavity, 104-Feeding zone, 105-Pyrolysis zone, 106-Discharge zone, 107-Conveyor belt, 108-Burner. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] like Figure 1 As shown, this invention provides a system for the resource-based treatment of waste lithium batteries based on thermal radiation, comprising a thermal radiation treatment unit, a cooling, splitting, crushing and sorting unit, and a resource recycling unit arranged sequentially; the thermal radiation treatment unit is used to perform pyrolysis treatment on the waste lithium batteries and to treat the pyrolysis gas generated during the pyrolysis process; the cooling, splitting, crushing and sorting unit is used to cool the waste lithium batteries after pyrolysis and to disassemble them after cooling; the resource recycling unit is used to process the positive electrode material and negative electrode material after disassembly.

[0055] The thermal radiation treatment unit includes a thermal radiation reactor for pyrolyzing waste lithium batteries. According to the conveying direction of the waste lithium batteries during the treatment process, the thermal radiation reactor is sequentially provided with a feeding zone 104, a pyrolysis zone 105, and a discharging zone 106. The feeding zone 104 is the area for feeding waste lithium batteries, the pyrolysis zone 105 is the area for pyrolyzing waste lithium batteries, and the discharging zone 106 is the area for discharging residual materials after the waste lithium batteries have been pyrolyzed.

[0056] The cooling and splitting breaking and sorting unit comprises a cooling tunnel kiln, a manual disassembling unit 9, a crusher 10 and a flotation device 11 arranged in sequence along the conveying direction. Since the pyrolyzed waste lithium battery still has a high temperature after removing the electrolyte, the binder and the separator, the waste lithium battery cannot be directly disassembled and needs to be cooled before disassembling. The cooling tunnel kiln is used for cooling the pyrolyzed waste lithium battery. The inlet end of the cooling tunnel kiln is connected with the outlet end of the discharging area 106. After being cooled by the cooling tunnel kiln, the workers of the manual disassembling unit take out the waste lithium battery from the outlet end of the cooling tunnel kiln and manually disassemble the waste lithium battery. After manual disassembly, the copper shell, the aluminum shell, the positive electrode material and the negative electrode material are obtained. The disassembled positive electrode material and negative electrode material are directly manually fed into the crusher 10. The crusher 10 is used for crushing the positive electrode material and the negative electrode material. The outlet end of the crusher 10 is connected with the inlet end of the flotation device 11. The positive electrode material and the negative electrode material are fed into the flotation device 11 after being crushed by the crusher 10. The flotation device 11 is used for screening the crushed materials. The screened copper material, iron material and aluminum material are collected, and the remaining materials are fed into the resource recycling unit.

[0057] The resource recycling unit comprises a lithium iron phosphate separation tank 12, a filter press I 13, an iron removal tank 14, a filter press II 15, a lithium carbonate reaction tank 16 and a filter press III 20 arranged in sequence along the conveying direction. After being screened by the flotation device 11, the copper material, the iron material and the aluminum material are fed into the lithium iron phosphate separation tank 12. Water and hydrochloric acid are added into the lithium iron phosphate separation tank 12 to react. The solid-liquid mixture generated in the lithium iron phosphate separation tank 12 is fed into the filter press I 13 to be filtered. After being filtered by the filter press I 13, graphite is separated. The solution filtered by the filter press I 13 is fed into the iron removal tank 14. Water, sodium hydroxide and hydrogen peroxide are added into the iron removal tank 14. The solid-liquid mixture generated in the iron removal tank 14 is fed into the filter press II 15 to be filtered. After being filtered by the filter press II 15, iron phosphate is separated. The solution filtered by the filter press II 15 is fed into the lithium carbonate reaction tank 16. Sodium carbonate is added into the lithium carbonate reaction tank 16. The solid-liquid mixture generated in the lithium carbonate reaction tank 16 is fed into the filter press III 20 to be filtered. After being filtered by the filter press III 20, lithium carbonate and sodium chloride solution are separated.

[0058] As Figure 2 , Figure 3As shown, the thermal radiation reactor comprises an inner cavity 102 and an outer cavity 103, the inner cavity 102 is not communicated with the outer cavity 103, so that the inner cavity 102 and the outer cavity 103 are two independent cavities completely closed, the feeding area 104, the pyrolysis area 105 and the discharging area 106 are all located in the inner cavity 102, the outer cavity 103 wraps the pyrolysis area 105, the heating medium in the outer cavity 103 heats the waste lithium battery in the pyrolysis area 105, and the waste lithium battery is not heated when it is in the feeding area 104 and the discharging area 106, so that the waste lithium battery is pyrolyzed in the pyrolysis area 105.

[0059] The feeding area 104, the pyrolysis area 105 and the discharging area 106 are all provided with a conveying belt 107, the three conveying belts 107 are all grid conveying belts, the conveying surfaces of the three conveying belts 107 are located on the same plane, and the three conveying belts 107 are sequentially butted. Meanwhile, in order to avoid that the heat or the pyrolysis gas in the pyrolysis area 105 is directly discharged to the outside of the inner cavity 102 through the feeding area 104 and the discharging area 106, hydraulic cut-off valves 101 are arranged between the two ends of the inner cavity 102, the feeding area 104 and the pyrolysis area 105, and the pyrolysis area 105 and the discharging area 106, and the hydraulic cut-off valve 101 is a gate driven by a hydraulic element. The feeding area 104, the pyrolysis area 105 and the discharging area 106 are isolated by the hydraulic cut-off valves 101, which not only effectively avoids that air enters the pyrolysis area 105, but also effectively reduces the conditions for the generation of dioxin.

[0060] When the waste lithium battery needs to be sent into the feeding area 104, open the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102, close the hydraulic cut-off valves 101 between the feeding area 104 and the pyrolysis area 105, between the pyrolysis area 105 and the discharging area 106, and at the outlet end of the internal cavity 102, put the waste lithium battery (without crushing and discharging) on the conveying belt 107 in the feeding area 104, and drive the conveying belt 107 in the feeding area 104 according to the stacking condition of the waste lithium battery on the conveying belt 107, so that the conveying belt 107 in the feeding area 104 is stacked with waste lithium batteries; then, open the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, and fill nitrogen into the pyrolysis area 105, when the oxygen concentration in the pyrolysis area 105 is less than 1%, heat the pyrolysis area 105 to 100℃, open the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, start the conveying belt 107 in the feeding area 104 and the pyrolysis area 105, convey the waste lithium battery in the feeding area 104 into the pyrolysis area 105, after the conveying is completed, immediately close the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, and the conveying belt 107 in the pyrolysis area 105, open the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102 after 1 min, and at the same time, fill the waste lithium battery on the conveying belt 107 in the feeding area 104, after the filling is completed, close the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102, and the conveying belt 107 in the feeding area 104.

[0061] When the temperature of the pyrolysis zone 105 is heated to 400-600 DEG C, the electrolyte in the waste lithium battery is sublimated to gas due to high temperature, and since the waste lithium battery is a closed container, the steam of the electrolyte expands sharply, generating a huge gas pressure, and the waste lithium battery explosion relief valve cannot withstand high pressure, the explosion relief valve opens, the electrolyte in the waste lithium battery continues to evaporate, and the PE or PP separator in the lithium battery is cracked into ethylene and propylene, and the PVDF binder of the positive and negative electrodes of the waste lithium battery is cracked into HF, vinylidene fluoride, 1,2,3-trifluorobenzene and 1,2-difluorobenzene; then, the waste lithium battery stays in the pyrolysis zone 105 for 30-70 min, the hydraulic cut-off valve 101 between the feeding zone 104 and the pyrolysis zone 105 and the pyrolysis zone 105 and the discharging zone 106 is opened, and the conveying belt 107 in the feeding zone 104, the conveying belt 107 in the pyrolysis zone 105 and the conveying belt 107 in the discharging zone 106 are started, the waste lithium battery on the conveying belt in the feeding zone 104 is conveyed to the conveying belt 107 in the pyrolysis zone 105, the waste lithium battery after pyrolysis in the pyrolysis zone 105 is conveyed to the conveying belt 107 in the discharging zone 106, and after the conveying is completed, the conveying belt 107 in the pyrolysis zone 105 and the conveying belt 107 in the discharging zone 106 are closed, the hydraulic cut-off valve 101 between the feeding zone 104 and the pyrolysis zone 105 and the hydraulic cut-off valve 101 between the pyrolysis zone 105 and the discharging zone 106 are closed, the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102 and the hydraulic cut-off valve 101 at the outlet end of the internal cavity 102 are opened, the conveying belt 107 in the feeding zone 104 and the conveying belt 107 in the discharging zone 106 are opened, the waste lithium battery is filled on the conveying belt 107 in the feeding zone 104, and the waste lithium battery after pyrolysis on the conveying belt 107 in the discharging zone 106 is sent into the cooling tunnel kiln.

[0062] In order to improve the processing thermal efficiency, the outer cavity 103 is also provided with a guide plate, which can be spirally wound in the outer cavity 103, so that a spiral channel is formed in the outer cavity 103, and a guide column can also be welded on the inner wall of the internal cavity 102. Since only the pyrolysis zone 105 needs to be heated, the guide column can be arranged only in the pyrolysis zone 105, thereby improving the thermal radiation rate of the heat energy to the waste battery.

[0063] In order to provide heat for the pyrolysis zone 105, the heat radiation reactor further comprises a burner 108, the fuel of the burner 108 can adopt natural gas, and the combustion cylinder of the burner 108 is in communication with the heat source inlet of the outer cavity 103, so that the high-temperature flue gas generated after the combustion of the burner 108 can be directly sent into the outer cavity 103 as a heat source. Of course, the fuel of the burner 108 in the present application can also use fuel oil, such as diesel oil, heavy oil, etc., and in the case of avoiding pollution and generating sufficient heat, the fuel of the burner 108 can also use other substances.

[0064] The heat radiation treatment unit further comprises a condenser 2, an oil recovery tank 3, a deacidification tower 4, and a NaF crystallizer 6. The condenser 2 is mainly used for cooling the pyrolysis gas generated in the pyrolysis process of the waste lithium battery, and thus the feed inlet of the condenser 2 is connected with the gas outlet of the pyrolysis zone 105, so that the pyrolysis gas generated in the pyrolysis process of the waste lithium battery can be directly sent into the condenser 2, and the macromolecular substances in the pyrolysis gas can be changed into oil after being cooled. In order to facilitate the discharge of the oil after being condensed, the pyrolysis gas is directly sent into the shell of the condenser 2, and the cooling medium is sent through the pipeline in the condenser 2. Since the oil formed after the condensation of the macromolecular substances in the pyrolysis gas contains ethyl carbonate, propylene carbonate, and various alkanes, alkenes, ketones, etc., in order to facilitate the recovery of the oil after being condensed, the discharge outlet of the condenser 2 is connected with the inlet end of the oil recovery tank 3, so that the oil after being condensed can be sent into the oil recovery tank 3 for storage. Since there is still a part of non-condensable gas after the condensation of the macromolecular substances in the pyrolysis gas, in order to remove the acidic substances in the non-condensable gas, the gas outlet of the condenser 2 is connected with the gas inlet of the deacidification tower 4, and the liquid outlet of the deacidification tower 4 is connected with the feed inlet of the NaF crystallizer 6. The deacidification tower 4 mainly removes HF in the non-condensable gas to prevent the corrosion of HF to the subsequent equipment, and the deacidification tower 4 can generate NaF by directly performing heat and mass transfer reaction between the sprayed sodium hydroxide solution and the non-condensable gas. Since NaF is a very important chemical product, the salt generated by the reaction between the sodium hydroxide solution and the non-condensable gas can be sent into the NaF crystallizer 6 for crystallization, and the crystallized product can be collected and directly sold.

[0065] The condenser 2 is a U-shaped tube heat exchanger, a tube plate heat exchanger, or a floating head heat exchanger, which can be selected at will under the condition of meeting the condensation of the macromolecular substances in the pyrolysis gas into oil and facilitating the discharge of the non-condensable gas.

[0066] The heat radiation treatment unit further comprises a NaOH preparation tank 5 for preparing the sodium hydroxide solution, and the liquid outlet of the NaOH preparation tank 5 is connected with the spraying structure in the deacidification tower 4. In order to facilitate the sending of the sodium hydroxide solution in the NaOH preparation tank 5 into the spraying structure in the deacidification tower 4, a pumping pump can be further arranged between the liquid outlet of the NaOH preparation tank 5 and the spraying structure in the deacidification tower 4.

[0067] In order to facilitate further treatment of the non-condensable gas after the removal of HF in the deacidification tower 4, the heat radiation treatment unit further comprises a gas-liquid separator 7, and the gas outlet of the deacidification tower 4 is connected with the gas inlet of the gas-liquid separator 7, so that the non-condensable gas after the removal of HF can be dehydrated in the gas-liquid separator 7. In order to fully utilize the non-condensable gas after the dehydration of the gas-liquid separator 7, the gas outlet of the gas-liquid separator 7 can be directly connected with the gas inlet of the combustor 108, so that the non-condensable gas after the dehydration of the gas-liquid separator 7 can be directly sent into the combustor 108 as fuel, which not only reduces the energy required by the combustor 108, but also makes the non-condensable gas after the dehydration of the gas-liquid separator 7 be fully utilized.

[0068] The cooling tunnel kiln comprises an inner cavity and an outer cavity, the outer cavity is wrapped outside the inner cavity, that is, the cooling tunnel kiln is a jacketed container, the outer cavity is used to pass through a heat exchange medium, the inner cavity is used to store the pyrolyzed waste lithium battery, and the outer cavity is provided with a cooling medium inlet and a cooling medium outlet, the cooling medium inlet is used to send the heat exchange medium into the outer cavity, and the cooling medium outlet is used to send the heat exchange medium out of the outer cavity. When the heat exchange medium is introduced into the outer cavity and the pyrolyzed waste lithium battery is sent into the inner cavity, the heat exchange medium exchanges heat with the pyrolyzed waste lithium battery, so that the temperature of the pyrolyzed waste lithium battery can be reduced to below 50 DEG C, and the workers of the manual disassembly unit 9 can directly take out the waste lithium battery after the cooling in the cooling tunnel kiln for disassembly, so as to obtain the copper shell, the aluminum shell, the positive electrode material and the negative electrode material.

[0069] In order to further treat the lithium carbonate and sodium chloride solution obtained after the pressure filtration of the pressure filter III 20, the resource recycling unit further comprises an evaporation crystallizer 18 and a dryer 17, the evaporation crystallizer 18 is used for crystallizing treatment of the sodium chloride solution, and the dryer 17 is used for drying the lithium carbonate. The feed inlet of the evaporation crystallizer 18 is connected with the liquid outlet of the pressure filter III 20, and the feed inlet of the dryer 17 is connected with the solid outlet of the pressure filter III 20, so that the lithium carbonate solid obtained after the pressure filtration of the pressure filter III 20 can be directly sent into the dryer 17 through the solid outlet of the pressure filter III 20 for drying, and the dried lithium carbonate can be directly sold after collection. The sodium chloride solution obtained after the pressure filtration of the pressure filter III 20 is directly sent into the evaporation crystallizer 18 through the liquid outlet of the pressure filter III 20 for crystallization, so as to recover the sodium salt. Since the dryer 17 generates high-temperature flue gas during the drying of the lithium carbonate, in order to avoid the pollution of the high-temperature flue gas discharged into the atmosphere to the environment, the flue gas treatment device 19 is further connected with the gas outlet of the dryer 17, so that the high-temperature flue gas generated during the drying of the lithium carbonate by the dryer 17 can be sent into the flue gas treatment device 19 for further treatment, thereby ensuring the health of the workers.

[0070] In the present application, since the NaF crystallizer 6 needs a heat source to realize the crystallization of the salt solution generated in the deacidification tower 4, the NaF crystallizer 6 is of a jacket structure, and in order to recycle the heat energy, the heat source inlet of the NaF crystallizer 6 is communicated with the heat source outlet of the external cavity 103, so that the high-temperature flue gas in the external cavity 103 of the heat radiation reactor can be directly sent into the jacket structure of the NaF crystallizer 6 after pyrolysis of the waste lithium battery to heat the salt solution in the NaF crystallizer 6, so that the salt solution in the NaF crystallizer 6 is crystallized; at the same time, in order to further utilize the high-temperature flue gas after heating the salt solution in the NaF crystallizer 6, the dryer 17 can also be a jacket structure dryer 17, and the heat source outlet of the NaF crystallizer 6 is directly connected with the heat source inlet of the dryer 17, so that the high-temperature flue gas after heating the salt solution in the NaF crystallizer 6 can be sent into the jacket structure of the dryer 17 for drying the lithium carbonate in the dryer 17.

[0071] At the same time, in the present application, the condenser 2 and the cooling medium of the cooling tunnel kiln can directly use tap water, in order to fully utilize the heat energy, the hot water generated by heat exchange between the pyrolysis gas generated in the pyrolysis zone 105 and the condenser 2 can be directly sent into the iron removal tank 14 for use, specifically, the water inlet of the iron removal tank 14 is connected with the heat exchange medium outlet of the condenser 2; at the same time, since the salt solution generated in the deacidification tower 4 will produce high-temperature evaporation gas during the crystallization in the NaF crystallizer 6, the high-temperature evaporation gas generated in the NaF crystallizer 6 can also be sent into the iron removal tank 14 through a pipeline, which can heat the iron removal tank 14. The hot water generated by heat exchange between the waste lithium battery after pyrolysis and the cooling tunnel kiln can be directly sent into the lithium iron phosphate separation tank 12 for use, specifically, the cooling medium outlet of the cooling tunnel kiln is connected with the lithium iron phosphate separation tank 12.

[0072] The present application also provides a method for recycling waste lithium battery based on heat radiation resources, the steps are as follows:

[0073] The recovered waste lithium battery is pyrolyzed, and in the pyrolysis process, the electrolyte in the waste lithium battery sublimates to gas due to high temperature, and since the battery is a closed container, the steam of the electrolyte expands sharply, generating a large gas pressure, and the explosion vent of the battery opens due to the high pressure, and the electrolyte in the lithium battery continues to evaporate, so that the electrolyte in the waste lithium battery is continuously discharged from the explosion vent, and the discharged electrolyte is evaporated to form pyrolysis gas in the pyrolysis process, and after the electrolyte in the waste lithium battery is completely evaporated, the waste lithium battery is cooled, and after the waste lithium battery is cooled, manual disassembly is carried out, and copper shell, aluminum shell, positive electrode material and negative electrode material are obtained after manual disassembly, and the copper shell and the aluminum shell are collected.

[0074] Then, the positive electrode material and the negative electrode material obtained by disassembling the waste lithium battery are crushed, and copper, iron and aluminum substances are screened from the crushed substances, and the remaining substances after screening are separated for three times, graphite is separated out in the first separation, the substances after the graphite is separated out in the first separation are separated for the second time, iron carbonate is separated out in the second separation, lithium carbonate is separated out in the third separation from the substances after the iron carbonate is separated out in the second separation.

[0075] In the pyrolysis process of the waste lithium battery, the pyrolysis temperature is 400-600℃, and the pyrolysis time is 30-70min.

[0076] In the pyrolysis process of the waste lithium battery, pyrolysis gas is generated, the pyrolysis gas generated by pyrolysis includes ethylene and propylene generated by pyrolysis of the separator PE or the separator PP in the waste lithium battery, HF, vinylidene fluoride, 1,2,3-trifluorobenzene and 1,2-difluorobenzene generated by pyrolysis of the binder PVDF of the positive and negative electrodes in the waste lithium battery, and electrolyte vapor generated when the electrolyte evaporates.

[0077] After the waste lithium battery is pyrolyzed, the generated pyrolysis gas is condensed, so that the macromolecular substances of the pyrolysis gas are condensed to form oil, and the oil mainly contains ethyl carbonate, propylene carbonate and various alkanes, alkenes and ketones.

[0078] The non-condensable gas still exists after the pyrolysis gas generated in the pyrolysis process of the waste lithium battery is condensed, and the non-condensable gas is reacted with a sodium hydroxide solution to remove HF in the non-condensable gas.

[0079] In the reaction process of the pyrolysis gas generated in the pyrolysis process of the waste lithium battery with the sodium hydroxide solution, a salt solution is generated, and the generated salt solution is crystallized to obtain NaF, which can be directly collected and sold. At the same time, in the reaction process of the pyrolysis gas generated in the pyrolysis process of the waste lithium battery with the sodium hydroxide solution, a part of the non-condensable gas which does not react with the sodium hydroxide solution solution is left, and the non-condensable gas is collected and dehydrated, and the dehydrated non-condensable gas can be directly used as fuel.

[0080] In order to avoid the workers from being scalded in the process of disassembling the waste lithium battery after pyrolysis, the temperature of the waste lithium battery after cooling is lower than 50℃, so as to avoid the inconvenience of disassembling due to the too low temperature of the waste lithium battery.

[0081] The positive electrode material and the negative electrode material obtained after disassembling are crushed, and the particle size of the crushed particles is less than 1mm, which is convenient for subsequent screening.

[0082] The positive electrode material and the negative electrode material obtained after disassembling are subjected to first separation after crushing and screening. The specific process of the first separation is as follows: the remaining material after screening is sent into water, hydrochloric acid is added, the pH value in the first separation process is 1.5-2.5, the temperature in the reaction process is kept at 30-45℃, after sufficient stirring, the reaction is carried out for 20-40 min, the solid-liquid mixture after reaction is subjected to pressure filtration, the solid material obtained after pressure filtration is graphite, and the solution obtained after pressure filtration is subjected to second separation.

[0083] The solution after the first separation is subjected to second separation. The specific process of the second separation is as follows: water, sodium hydroxide and hydrogen peroxide are added to the solution after the first separation, the pH value in the second separation process is 4.2-5.6, the temperature in the reaction process is kept at 85-95℃, after sufficient stirring, the reaction is carried out for 40-60 min, the solid-liquid mixture after reaction is subjected to pressure filtration, the solid material obtained after pressure filtration is iron phosphate, and the solution obtained after pressure filtration is subjected to third separation.

[0084] The solution after the second separation is subjected to third separation. The specific process of the third separation is as follows: sodium carbonate is added to the solution after the second separation, the pH value in the third separation process is 11-12, after sufficient stirring, the reaction is carried out for 30-50 min, the solid-liquid mixture after reaction is subjected to pressure filtration, the solid material obtained after pressure filtration is lithium carbonate, and the liquid material obtained after pressure filtration is sodium chloride solution.

[0085] The sodium chloride solution obtained after the third separation is subjected to crystallization treatment, and the lithium carbonate obtained after the third separation is subjected to drying. The lithium carbonate after drying can be directly sold after collection.

[0086] The specific treatment method of the waste lithium battery in the system is as follows:

[0087] When the waste lithium battery needs to be sent into the feeding area 104, open the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102, close the hydraulic cut-off valves 101 between the feeding area 104 and the pyrolysis area 105, between the pyrolysis area 105 and the discharging area 106, and at the outlet end of the internal cavity 102, put the waste lithium battery (without crushing and discharging) on the conveying belt 107 in the feeding area 104, and drive the conveying belt 107 in the feeding area 104 according to the stacking condition of the waste lithium battery on the conveying belt 107, so that the conveying belt 107 in the feeding area 104 is stacked with waste lithium batteries; then, open the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, and fill nitrogen into the pyrolysis area 105, when the oxygen concentration in the pyrolysis area 105 is less than 1%, heat the pyrolysis area 105 to 100℃, open the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, start the conveying belt 107 in the feeding area 104 and the pyrolysis area 105, convey the waste lithium battery in the feeding area 104 into the pyrolysis area 105, after the conveying is completed, immediately close the hydraulic cut-off valve 101 between the feeding area 104 and the pyrolysis area 105, and the conveying belt 107 in the pyrolysis area 105, open the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102 after 1 min, and at the same time, fill the waste lithium battery on the conveying belt 107 in the feeding area 104, after the filling is completed, close the hydraulic cut-off valve 101 at the inlet end of the internal cavity 102, and the conveying belt 107 in the feeding area 104.

[0088] When the temperature of the pyrolysis zone 105 is heated to 470℃, the electrolyte in the waste lithium battery sublimates into gas due to high temperature. Since the waste lithium battery is a sealed container, the steam of the electrolyte expands sharply, generating a large gas pressure. The pressure relief valve of the waste lithium battery cannot withstand the high pressure, so the pressure relief valve opens. The electrolyte in the waste lithium battery continues to evaporate and is discharged from the pressure relief valve in a continuous manner. The separator PE or PP in the lithium battery is pyrolyzed into ethylene and propylene. The binder PVDF of the positive and negative electrodes of the waste lithium battery is pyrolyzed into HF, vinylidene fluoride, 1,2,3-trifluorobenzene, and 1,2-difluorobenzene. Then, after the waste lithium battery stays in the pyrolysis zone 105 for 60 minutes, the hydraulic shut-off valve 101 between the feeding zone 104 and the pyrolysis zone 105 and between the pyrolysis zone 105 and the discharging zone 106 is opened, and the conveyer belt 107 in the feeding zone 104, the conveyer belt 107 in the pyrolysis zone 105, and the conveyer belt 107 in the discharging zone 106 are started. The waste lithium battery on the conveyer belt 107 in the feeding zone 104 is transported to the conveyer belt 107 in the pyrolysis zone 105, and the pyrolyzed waste lithium battery in the pyrolysis zone 105 is transported to the conveyer belt 107 in the discharging zone 106. After the transportation is completed, the conveyer belt 107 in the pyrolysis zone 105 and the conveyer belt 107 in the discharging zone 106 are closed, and the hydraulic shut-off valve 101 between the feeding zone 104 and the pyrolysis zone 105 and between the pyrolysis zone 105 and the discharging zone 106 is closed. The hydraulic shut-off valve 101 at the inlet end of the internal cavity 102 and the hydraulic shut-off valve 101 at the outlet end of the internal cavity 102 are opened, and the conveyer belt 107 in the feeding zone 104 and the conveyer belt 107 in the discharging zone 106 are started. The waste lithium battery is filled on the conveyer belt 107 in the feeding zone 104, and the pyrolyzed waste lithium battery on the conveyer belt 107 in the discharging zone 106 is sent into the internal cavity of the cooling tunnel kiln.

[0089] Tap water is sent into the external cavity of the cooling tunnel kiln. The waste lithium battery in the upper internal cavity of the cooling tunnel kiln exchanges heat with the tap water in the external cavity of the cooling tunnel kiln. The tap water in the external cavity of the cooling tunnel kiln is heated, and the waste lithium battery in the internal cavity is cooled to 50℃. Then, the worker of the manual disconnection unit takes out the waste lithium battery from the outlet end of the cooling tunnel kiln and manually disassembles it. After manual disassembly, the copper shell, aluminum shell, positive electrode material, and negative electrode material are obtained. The disassembled positive electrode material and negative electrode material are directly sent into the crusher 10 by manual operation. The crusher 10 crushes the positive electrode material and negative electrode material. The crushed positive electrode material and negative electrode material are sent into the flotation equipment 11. The flotation equipment 11 is used to screen the crushed materials. The screened copper materials (such as Figure 4 ), iron materials, and aluminum materials (such as Figure 5 ) are collected, and the remaining materials are sent into the lithium iron phosphate separation tank 12.

[0090] The cooled tunnel kiln is sent to the lithium iron phosphate separation tank 12, and hydrochloric acid is added to the lithium iron phosphate separation tank 12 for reaction, so that the PH value in the lithium iron phosphate separation tank is 2, the temperature is 40℃, and stirring is performed for 20 minutes. The solid-liquid mixture generated after the reaction is sent to the filter press I 13 for pressure filtration, and graphite is separated after the pressure filtration of the filter press I 13, as shown in Figure 6 The solution filtered by the filter press I 13 is sent to the iron removal tank 14, and hot water generated by heat exchange between the condenser 2 and the pyrolysis gas generated in the pyrolysis zone 105 is added to the iron removal tank 14. Sodium hydroxide and hydrogen peroxide are added to the iron removal tank 14, so that the PH value in the iron removal tank 14 is 4.5, the temperature is 90℃, and stirring is performed for 50 minutes. The solid-liquid mixture generated in the iron removal tank 14 is sent to the filter press II 15 for pressure filtration, and iron phosphate is separated after the pressure filtration of the filter press II 15. The solution filtered by the filter press II 15 is sent to the lithium carbonate reaction tank 16, and sodium carbonate is added to the lithium carbonate reaction tank 16, so that the PH value in the lithium carbonate reaction tank 16 is 12, and stirring is performed for 40 minutes. The solid-liquid mixture generated in the lithium carbonate reaction tank 16 is sent to the filter press III 20 for pressure filtration, and lithium carbonate and sodium chloride solution are separated after the pressure filtration of the filter press III 20. Lithium carbonate is as shown in Figure 7 The lithium carbonate is sent to the dryer 17, and the lithium carbonate is dried by heat exchange with the high-temperature flue gas in the jacket structure of the dryer 17. The sodium chloride solution is sent to the evaporation crystallizer 18, and sodium chloride crystals are generated by crystallization of the sodium chloride solution in the evaporation crystallizer 18.

[0091] At the same time, the pyrolysis gas generated in the pyrolysis zone 105 of the waste lithium battery is directly sent to the condenser 2, and the pyrolysis gas is heat-exchanged with the tap water in the condenser 2 to generate oil, and the generated oil is stored in the oil recovery tank 3. The uncondensed gas in the pyrolysis gas is sent to the deacidification tower 4, and the NaOH preparation tank 5 provides sodium hydroxide solution to the spraying structure in the deacidification tower 4. The spraying structure in the deacidification tower 4 sprays the sodium hydroxide solution to react with the uncondensed gas in the condenser 2 to generate NaF solution, and the NaF solution is sent to the NaF crystallizer 6. The high-temperature flue gas in the outer cavity 103 is sent to the jacket structure of the NaF crystallizer 6, and the NaF solution is crystallized by heat exchange with the high-temperature flue gas in the jacket structure of the NaF crystallizer 6. The crystallized product is collected and directly sold, and the high-temperature evaporation gas generated during the crystallization of the NaF solution in the NaF crystallizer 6 is directly sent to the iron removal tank 14. The high-temperature flue gas in the jacket structure of the NaF crystallizer 6 is sent to the jacket structure of the dryer 17 for reuse.

[0092] The non-condensable gas in the pyrolysis gas which is not condensed is still left after reacting with the sodium hydroxide solution in the deacidification tower 4. The non-condensable gas is sent to the gas-liquid separator 7. The gas-liquid separator 7 removes the water in the non-condensable gas. The non-condensable gas after dehydration in the gas-liquid separator 7 can be directly sent to the combustor 108 as fuel.

[0093] The oil obtained after condensation by the condenser 2 is detected. The ratio of each component in the oil is shown in the following table:

[0094] Serial No. Name of Component Proportion (%) 1 Vinyl Carbonate 28 2 Ethyl Methyl Carbonate 23 3 Dimethyl Carbonate 25 4 Propylidene Carbonate 5 5 Lithium Hexafluorophosphate 15 6 Propanesulfonic Acid Lactone 1 7 Vinlylene Carbonate 2 8 Bisfluorooxalato Borate 1

[0095] In the description of the present specification, the description of the terms "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the person skilled in the art can combine and combine the different embodiments / ways or examples described in the present specification and the features of the different embodiments / ways or examples, without contradiction.

[0096] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0097] The person skilled in the art should understand that the above-mentioned embodiments are only for the purpose of clearly illustrating the present application, and are not intended to limit the scope of the present application. Based on the above disclosure, other changes or modifications can also be made by those skilled in the art, and these changes or modifications are still within the scope of the present application.

Claims

1. A method for resource utilization of waste lithium batteries based on thermal radiation, characterized in that, The steps are as follows: The pyrolysis of the recovered waste lithium battery makes the electrolyte evaporate, and after the waste lithium battery is cooled, the copper shell, aluminum shell, positive electrode material and negative electrode material are obtained; The positive electrode material and the negative electrode material are crushed and screened to obtain copper, iron and aluminum substances, and the remaining substances are separated three times to obtain graphite in the first separation, iron phosphate in the second separation, and lithium carbonate and sodium chloride in the third separation; It also includes a system for implementing the above method, including a heat radiation treatment unit, a cooling disassembly crushing and sorting unit, and a resource recovery unit arranged in sequence; The heat radiation treatment unit includes a heat radiation reactor, and the heat radiation reactor is provided with a feeding area (104), a pyrolysis area (105) and a discharging area (106) in sequence along the conveying direction; The cooling disassembly crushing and sorting unit includes a cooling tunnel kiln, a manual disassembly unit (9), a crusher (10) and a flotation device (11) arranged in sequence along the conveying direction; The resource recovery unit includes lithium iron phosphate separation tank (12), filter press I (13), iron removal tank (14), filter press II (15), lithium carbonate reaction tank (16) and filter press III (20) arranged in sequence along the conveying direction.

2. The method of claim 1, wherein, The pyrolysis temperature of the waste lithium battery is 400-600℃, and the pyrolysis time is 30-70min.

3. The method of claim 1, wherein, The temperature of the waste lithium battery after cooling is lower than 50℃.

4. The method of claim 1, wherein, The particle size of the crushed positive electrode material and negative electrode material is less than 1mm.

5. The method according to claim 1 or 2, characterized in that, The pyrolysis gas generated during the pyrolysis of the waste lithium battery includes ethylene and propylene generated by the thermal cracking of the separator PE or separator PP in the waste lithium battery, HF, vinylidene fluoride, 1,2,3-trifluorobenzene and 1,2-difluorobenzene generated by the thermal cracking of the binder PVDF of the positive and negative electrodes in the waste lithium battery, and electrolyte vapor generated during the evaporation of the electrolyte.

6. The method of claim 5, wherein, The pyrolysis gas generated during the pyrolysis of the waste lithium battery is condensed to obtain oil containing ethyl acetate, propylene carbonate and alkanes, alkanes and ketones.

7. The method of claim 6, wherein, The non-condensable gas after condensation reacts with sodium hydroxide solution to remove HF in the non-condensable gas.

8. The method of claim 7, wherein, The salt generated by the reaction of the non-condensable gas with the sodium hydroxide solution is crystallized, and the deacidified non-condensable gas is dehydrated, and the dehydrated non-condensable gas is used as fuel.

9. The method of claim 1, wherein, The first separation is: the remaining material after screening is sent into water, and hydrochloric acid is added, and the PH in the first separation process is 1.5-2.5, the temperature is 30-45℃, and the reaction time is 20-40min.

10. The method of claim 1, wherein, The second separation is: water, sodium hydroxide and hydrogen peroxide are added to the solution after the first separation, and the PH in the second separation process is 4.2-5.6, the temperature is 85-95℃, and the reaction time is 40-60min.

11. The method of claim 1, wherein, The third separation is: sodium carbonate is added to the solution after the second separation, and the PH in the third separation process is 11-12, and the reaction time is 30-50min.

12. The method of claim 1 or 11, wherein, The remaining solution after the third separation is crystallized.

13. The method of claim 1, wherein, The heat radiation reactor comprises an inner cavity (102) and an outer cavity (103), a feeding zone (104), a pyrolysis zone (105) and a discharging zone (106) are located in the inner cavity (102), and the outer cavity (103) is wrapped around the periphery of the pyrolysis zone (105).

14. The method of claim 13, wherein, A conveying belt (107) is arranged in each of the feeding zone (104), the pyrolysis zone (105) and the discharging zone (106), the three conveying belts (107) are sequentially connected, and a hydraulic shut-off valve (101) is arranged at both ends of the inner cavity (102), between the feeding zone (104) and the pyrolysis zone (105), and between the pyrolysis zone (105) and the discharging zone (106).

15. The method of claim 13, wherein, A guide plate is further arranged in the outer cavity (103), and a guide column is further arranged on the inner wall of the inner cavity (102), and the guide column is located in the pyrolysis zone (105).

16. The method of claim 13, wherein, The heat radiation reactor further comprises a burner (108), and a combustion cylinder of the burner (108) is in communication with a heat source inlet of the outer cavity (103).

17. The method of claim 13, wherein, The heat radiation treatment unit further comprises a condenser (2), an oil recovery tank (3), a deacidification tower (4) and a NaF crystallizer (6), a feeding inlet of the condenser (2) is connected with a gas outlet of the pyrolysis zone (105), a discharging outlet of the condenser (2) is connected with the oil recovery tank (3), a gas outlet of the condenser (2) is connected with a gas inlet of the deacidification tower (4), and a liquid outlet of the deacidification tower (4) is connected with a feeding inlet of the NaF crystallizer (6).

18. The method of claim 17, wherein, A heat source inlet of the NaF crystallizer (6) is in communication with a heat source outlet of the outer cavity (103).

19. The method of claim 17, wherein, The heat radiation treatment unit further comprises a NaOH preparation tank (5), and a liquid outlet of the NaOH preparation tank (5) is connected with a spraying structure in the deacidification tower (4).

20. The method of claim 17, wherein, The heat radiation treatment unit further comprises a gas-liquid separator (7), and a gas outlet of the deacidification tower (4) is connected with a gas inlet of the gas-liquid separator (7).

21. The method of claim 1, wherein, The cooling tunnel kiln comprises an inner cavity and an outer cavity, the outer cavity is wrapped around the inner cavity, and a cooling medium inlet and a cooling medium outlet are arranged on the outer cavity.

22. The method of claim 13, wherein, A water inlet of the lithium iron phosphate separation tank (12) is connected with the cooling medium outlet; and a water inlet of the iron removal tank (14) is connected with a heat exchange medium outlet of the condenser (2).

23. The method of claim 1, wherein, The resource recovery unit further comprises an evaporation crystallizer (18) and a dryer (17), a feeding inlet of the evaporation crystallizer (18) is connected with a liquid outlet of the pressure filter III (20), a feeding inlet of the dryer (17) is connected with a solid outlet of the pressure filter III (20), and a flue gas treatment device (19) is further connected with a gas outlet of the dryer (17).

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