A combined treatment method for preparing PbO and complete electrolyte by wet recovery of waste lead-acid and lithium batteries

Abstract

The present application belongs to the technical field of battery recycling, and particularly relates to a combined treatment method for preparing PbO and complete electrolyte by wet recovery of waste lead-acid and lithium batteries, comprising the following steps: step 01: incoming material classification, sorting and pretreatment; step 02: branch crushing and screening pretreatment, divided into two lead-acid branches and a lithium battery main line branch; step 03: lead-acid solid phase synergistic pre-reduction; step 04: lead-acid acetic acid closed loop leaching-desulfurization-high purity PbO preparation; step 05: lithium battery superheated steam anaerobic cracking; step 06: lithium battery electrolyte supercritical CO2 extraction; step 07: waste water and waste gas synergistic centralized treatment; the present application has the beneficial effects of high recovery rate, high purity, double electrolyte recovery parallel process, adaptation to industrialized continuous mass production and the like.

Description

Technical Field

[0001] This invention belongs to the field of power construction equipment technology, and in particular discloses a combined treatment method for the wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte. Background Technology

[0002] With the rapid development of the automotive, energy storage, and digital consumer markets, the scale of waste lead-acid and lithium-ion batteries generated continues to expand. Currently, the industry generally adopts a separate plant disposal model for the two types of batteries, which has prominent problems such as large plant area, repeated purchase of complete sets of equipment, and high overall recycling and operating costs.

[0003] Existing waste lead-acid battery recycling processes have multiple drawbacks: traditional pyrometallurgical smelting processes generate large amounts of lead dust and toxic sulfur dioxide fumes, and require high investment in end-of-pipe environmental treatment; conventional wet electrolysis processes involve high equipment investment and require the use of toxic fluoride reagents during production; existing single acetic acid wet processes can only process lead paste materials alone and cannot be simultaneously integrated with the resource recovery process of valuable metals and electrolytes from lithium-ion batteries, resulting in poor process adaptability.

[0004] The existing mainstream lithium-ion battery recycling routes each have their own shortcomings:

[0005] Liquid nitrogen cryogenic crushing and vacuum pyrolysis processes can cause the organic components of the electrolyte to decompose, generating fluorine-containing pollutants, which are difficult to purify and treat in the future.

[0006] Although supercritical CO2 extraction can completely preserve electrolyte components, the single batch processing scale is small, making it difficult to adapt to large-scale mixed and continuous production.

[0007] Conventional high-temperature direct pyrolysis will completely destroy the lithium salt electrolyte, which can only achieve the harmless disposal of the battery and cannot regenerate and reuse the electrolyte; traditional steam cracking process only recovers solid metal materials and does not have a supporting lead paste resource recovery process.

[0008] Currently, the industry lacks a complete set of process solutions that can integrate and coordinate the treatment of two types of waste batteries. Lead-acid and lithium battery production lines are completely separate, and equipment such as crushing, condensation, wastewater treatment, and tail gas incineration cannot be shared. It is difficult to simultaneously produce high-purity PbO raw materials and directly reusable lithium battery electrolytes. The overall metal recovery rate and material recycling rate are low, resulting in insufficient resource utilization and environmental benefits. Summary of the Invention

[0009] To address the aforementioned problems, the present invention aims to disclose a combined treatment method for the wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte, which is achieved using the following technical solution.

[0010] A combined treatment method for the wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte includes the following steps:

[0011] Step 01: Incoming material classification, sorting, and pre-processing;

[0012] Step 02: Pre-treatment by splitting the crushing and screening into two lead-acid branches and a lithium battery main line branch;

[0013] Step 03: Lead-acid solid-phase synergistic pre-reduction;

[0014] Step 04: Leaching of lead-acetic acid through closed-ring desulfurization and preparation of high-purity PbO;

[0015] Step 05: Lithium-ion battery superheated steam anaerobic pyrolysis;

[0016] Step 06: Supercritical CO2 extraction of lithium battery electrolyte;

[0017] Step 07: Centralized treatment of wastewater and exhaust gas.

[0018] The above-described method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and complete electrolyte involves, in step 01, manually or using equipment sorting of the waste batteries into two independent material inlet channels: lead-acid battery packs and lithium-ion battery packs.

[0019] The pretreatment of lead-acid battery packs involves charging individual lead-acid cells at a constant voltage of 2.45V and a current-limited rate of 0.02C for 4 to 10 hours to stably convert the active material inside the plates into Pb / PbO2.

[0020] The pretreatment of lithium-ion battery packs involves discharging the lithium-ion batteries uniformly until the individual cell voltage is <1V, rinsing the surface electrolyte with clean water, and then drying them for later use.

[0021] The above-described method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte, in step 02, lead-acid branch: the lead-acid battery that has completed full-charge pretreatment is sent to the crusher for dismantling, and multi-stage screening achieves three-phase separation: the waste sulfuric acid liquid phase is separated and collected separately for resource recycling, the remaining metal grid and lead paste solid phase are mixed, crushed and passed through a 100-mesh standard sieve, and the coarse particles that do not meet the standard are returned to the crusher for secondary crushing;

[0022] Lithium battery main line branch: All types of lithium batteries are directly fed into a closed steam reactor, without the need for pre-deep crushing. The battery casing is automatically cracked by superheated steam, simplifying the pre-crushing process.

[0023] The above-described method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte involves the following steps: In step 03, the screened grid powder is thoroughly mixed with lead paste and kept at a constant temperature of 100-300℃ for 0.5-3 hours under normal pressure. PbO and PbSO4 are generated by the solid-phase oxidation-reduction reaction of elemental lead and lead dioxide. Then, a hydrogen peroxide-sulfite compound reducing agent is added, and the mixture is stirred at a constant temperature of 10-40℃ for 10-120 minutes to convert all high-valence lead components in the material into a divalent lead solid-phase mixture. The amount of hydrogen peroxide-sulfite compound reducing agent added is 0.2-0.5 times the mass of the lead paste.

[0024] The above-described method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte includes the following steps: In step 04, a mixed leaching solution of acetic acid and sodium acetate is prepared, with a mass ratio of acetic acid to sodium acetate of 0.1-0.9, and the pH of the system controlled at 4-7. The total amount of leaching solution used is 5-20 times the mass of lead paste. The divalent lead solid mixture is placed in the acetic acid-sodium acetate mixed leaching solution and leached by stirring at 15-80°C for 30-180 minutes. The solution is then filtered to remove clay and plastic impurities. Barium acetate is added to the filtrate, with the amount of barium acetate added being 0.2-1 times the mass of lead paste. The pH of the system is adjusted accordingly. The reaction is maintained at 4-8 or 10-40℃ for 10-120 min, and sulfate and barium ions are directionally precipitated to obtain BaSO4 solid byproduct. The filtrate is a high-purity lead acetate solution. 0.5-5 mol / L sodium hydroxide / potassium hydroxide / ammonia water alkaline precipitant is added to the lead acetate solution, and the precipitation is carried out at a constant temperature of 10-80℃ for 1-60 min. After filtration, multiple water washing and drying, high-purity PbO product is obtained. All acetate mother liquor separated in the precipitation process is transferred back to the upstream acetic acid leaching process to realize a closed-loop circulation of reagents. The leaching wastewater is sent to a public integrated water treatment system.

[0025] The aforementioned method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte involves the following steps: In step 05, softened water is generated into superheated steam at 625-690℃ and 0.99-2.0MPa via a steam generator. This steam is continuously introduced into a sealed reactor to purge internal air, maintaining an oxygen-free, sealed environment throughout the process. The reactor is then subjected to constant-temperature pyrolysis for 120-150 minutes. The high-temperature steam automatically expands and cracks the battery casing, causing the organic solvent in the electrolyte to vaporize and the lithium salt components to dissolve in the condensed steam. The mixed flue gas is discharged to the condenser for cooling and condensation. The condensate is sent to the oil-water separator for stratified treatment: the upper organic phase is collected, stored, purified, and reused in production, while the lower lithium- and fluorine-containing heavy metal wastewater is uniformly transported to a public integrated water treatment system. After the pyrolysis is completed, the material is discharged to obtain complete copper-aluminum shells and high-purity cathode powder. The purity of the lithium iron phosphate cathode powder is ≥90%, and the comprehensive recovery rate of solid metals is ≥80%. The combustible waste gases H2, CO, and CH4 generated by pyrolysis are uniformly sent to the burner for complete combustion and are discharged in a harmless and compliant manner.

[0026] The aforementioned method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte, in step 06, for lithium battery materials requiring complete recovery of electrolyte components: the discharged and dried battery cells are broken down under an inert protective atmosphere and sent to a supercritical CO2 extraction device; the extraction conditions are controlled at 30~50℃ and 15~35MPa to reach a supercritical fluid state, and continuously fed into the extraction vessel until the vessel is completely filled with supercritical CO2; the fluid inlet and outlet valves are closed to form a completely closed static system with no medium circulation, and static soaking is performed for 10~30 minutes; the high-pressure circulation pump is started to continuously and directionally circulate the supercritical CO2 in the vessel, entering a dynamic flushing condition for 10~50 minutes; the CO2 medium is depressurized and recycled for reuse, and the undecomposed part is obtained by depressurization separation. The mixed electrolyte of lithium salt and carbonate can be directly prepared and reused, making it suitable for small-batch, fine-grained recycling scenarios.

[0027] In the aforementioned method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte, in step 07, the wastewater generated from the lead-acid leaching process and the lithium-containing wastewater from the lower layer of the lithium battery oil-water separation are mixed and fed into a comprehensive water treatment system for stepwise precipitation and recovery of valuable metal salts such as lead salt, lithium salt, and fluoride salt; the fugitive waste gas from the lead-acid section and the combustible waste gas from lithium battery cracking are collected and uniformly burned for treatment, and the exhaust gas is discharged in compliance with standards.

[0028] The aforementioned method for the combined wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte, in step 07, involves adding agents such as sodium carbonate and sodium hydroxide to the integrated water treatment system to... It is converted into lead carbonate or lead hydroxide precipitate. The pH value is controlled at 8-9, and lead ions can be effectively precipitated and removed. The precipitate product can be obtained by filtration, washing and drying.

[0029] By adding reagents such as sodium carbonate and sodium phosphate, lithium ions are converted into lithium carbonate or lithium phosphate precipitates.

[0030] By adding agents such as calcium chloride and calcium hydroxide, fluoride ions react with calcium ions to form insoluble calcium fluoride precipitate, achieving a fluoride removal rate of over 98%. The concentration after treatment can be reduced to below 5 mg / L, and the precipitated calcium fluoride can be further processed into fluoride salt products.

[0031] The above-described method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte includes a crusher comprising a rolling crusher, a knife crusher, a plastic material separation and collection device, a hammer mill, a battery material separation device, a cyclone separator, a metal material storage silo, and a second vibrating screen.

[0032] An electric conveyor belt is installed between the crusher and the knife crusher. The material crushed by the crusher is fed into the knife crusher via the electric conveyor belt. After being crushed by the knife crusher, the material is sent into the plastic material separation and collection device. The plastic material separation and collection device is connected to the plastic material storage bin and the hammer crusher. The plastic part is sucked into the plastic material storage bin by a vacuum pump, the dust enters the dust collection device, and the rest is sent into the hammer crusher for further crushing. The battery material separation device after being crushed by the hammer crusher has metal material entering the metal material storage bin and then being sent to the second vibrating screen via the electric conveyor belt. The second vibrating screen is a 100-mesh standard screen. Coarse particles that do not meet the standard are returned to the crusher for secondary crushing.

[0033] Positive and negative electrode materials enter the positive and negative electrode material separation equipment, and the positive and negative electrode materials are discharged from different outlets to achieve separation and collection of positive and negative electrode materials.

[0034] This application has the following beneficial effects:

[0035] The lead-acid material adopts a closed-loop wet process of full-charge pre-stabilization + solid-phase self-reduction acetic acid. It relies on the reduction of high-valence lead components in the lead paste by the metal element of the grid to greatly reduce the amount of external reducing agent added. The acetate mother liquor is recycled in a closed loop throughout the process to prepare high-purity PbO that can be directly used in the manufacture of battery cathodes. The by-product industrial-grade barium sulfate can be sold externally to increase the added value of the product.

[0036] The lithium battery materials are produced using a closed, oxygen-free superheated steam pyrolysis process at 625~690℃, which completely eliminates the risk of electrolyte spontaneous combustion and toxic fumes. After pyrolysis, the shell, copper-aluminum current collector, and positive electrode active powder are structurally intact, with a solid metal recovery rate of ≥80% and a purity of up to 90% for lithium iron phosphate positive electrode powder.

[0037] A dual-electrolyte recovery parallel process is set up: large-scale industrial metal recovery uses steam cracking to separate the electrolyte organic solvent; for small-batch, fine electrolyte regeneration needs, a supercritical CO2 extraction branch line is added, and the two processes can be flexibly switched to adapt to different incoming material conditions.

[0038] The condensate wastewater generated by the two types of battery production systems is uniformly collected into a comprehensive water treatment unit for centralized treatment, and valuable components such as lead salt, lithium salt, and fluoride salt are recovered in stages; the waste gas from the entire process is uniformly collected and incinerated to meet emission standards. The amount of waste generated is far lower than that of the two independent production lines, making it green and low-carbon, and suitable for continuous industrial mass production.

[0039] The organic solvent in the upper layer of the oil-water separation by steam cracking can be purified and reused in production; supercritical CO2 extraction can completely retain the lithium salt and carbonate solvent components of LiPF6, realize high-value regeneration of electrolyte, and significantly improve the overall economic benefits of recycling waste batteries.

[0040] This invention adopts a dual-line parallel collaborative processing architecture, with lead-acid and lithium battery production lines sharing common equipment for condensation, oil-water separation, integrated water treatment, and tail gas incineration, reducing redundant equipment investment and plant footprint. The lead-acid recovery route relies on a grid-type elemental lead solid-phase self-reduction + barium acetate desulfurization closed-loop wet process system, with low external reducing agent dosage and significantly reduced acetic acid reagent consumption through mother liquor recycling, producing high-purity PbO at low cost, and achieving external sales value-added from the by-product barium sulfate; the lithium battery adopts a dual-process parallel route: high-temperature anaerobic steam cracking is suitable for large-scale continuous metal recovery, relying on high-temperature steam for automatic shell breaking, completely preserving metal and cathode powder, and simultaneously separating organic solvents; the supercritical CO2 extraction branch is adapted for small-batch fine production, completely preserving the lithium salt solvent components of the electrolyte, and achieving electrolyte regeneration; the waste liquid and waste gas generated by the two types of waste batteries are treated centrally and collaboratively, simultaneously recovering multiple valuable materials such as lead, lithium, barium, and organic solvents. The entire process is streamlined, the reagent recycling rate is high, and the emissions of waste gas, wastewater, and solid waste are significantly reduced, taking into account both environmental benefits and resource recovery economic benefits. Attached Figure Description

[0041] Figure 1 This is a flowchart of the lead-acid and lithium battery synergistic joint processing method according to an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the overall distribution of lead-acid and lithium battery synergistic joint processing in an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram of a supercritical CO2 extraction device for lithium battery electrolyte according to an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram of a closed steam oxygen-free pyrolysis furnace according to an embodiment of the present invention.

[0045] Figure 5 This is a schematic diagram of an integrated acetic acid leaching and filtration device according to an embodiment of the present invention.

[0046] Figure 6 This is a schematic diagram of a crusher according to an embodiment of the present invention.

[0047] In the figure, the attached figures are labeled as follows: 1. Electric conveyor belt, 2. Crusher, 3. Knife crusher, 4. Plastic material separation and collection device, 5. Dust collection device, 6. Hammer mill, 7. Battery material separation device, 8. Metal material storage silo, 9. Second vibrating screen, 10. Cyclone, 12. Upper outlet of cyclone (graphite), 13. Bottom outlet of cyclone (positive electrode material), 14. Vacuum pump, 41. Plastic material storage silo, 71. Air compressor. Detailed Implementation

[0048] Example 1: As Figures 1 to 5A combined treatment method for the wet recycling of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte includes the following steps:

[0049] Step 01: Incoming material sorting and pre-processing. Waste batteries are sorted manually or by equipment into two independent incoming material channels: lead-acid battery packs and lithium-ion battery packs. Lead-acid individual cells are charged at a constant voltage of 2.45V and a current-limited constant current of 0.02C for 4~10 hours to stabilize the active material inside the plates into Pb / PbO2, eliminating the risk of breakage, short circuit and fire. Lithium-ion batteries are discharged uniformly until the individual cell voltage is <1V, the surface electrolyte is rinsed with clean water and then dried for later use.

[0050] Step 02: Branch crushing and screening pretreatment, divided into two branches;

[0051] Branch 1 - Lead-acid Branch: Lead-acid batteries that have completed full-charge pretreatment are sent to the crusher for dismantling, and multi-stage screening achieves three-phase separation: the waste sulfuric acid liquid phase is separated and collected separately for resource recycling;

[0052] Waste sulfuric acid solution is separated by pretreatment and slag removal followed by direct negative pressure flash evaporation / MVR evaporation;

[0053] The remaining metal grid and lead paste are mixed, crushed, and passed through a 100-mesh standard sieve. Coarse particles that do not meet the standard are returned to the crusher for secondary crushing.

[0054] The crusher includes a rolling crusher 2, a knife crusher 3, a plastic material separation and collection device 4, a hammer crusher 6, a battery material separation device 7, a cyclone separator 10, a metal material storage bin 8, and a second vibrating screen 9.

[0055] An electric conveyor belt 1 is installed between the crusher 2 and the knife crusher 3. The material crushed by the crusher 2 is sent to the knife crusher 3 via the electric conveyor belt 1. After being crushed by the knife crusher 3, the material is sent to the plastic material separation and collection device 4. The plastic material separation and collection device 4 is connected to the plastic material storage bin 41 and the hammer crusher 6. The plastic part is sucked into the plastic material storage bin 41 by the vacuum pump 14, the dust enters the dust collection device 5, and the remaining part is sent to the hammer crusher 6 for further crushing. The battery material separation device 7 after being crushed by the hammer crusher 6, the metal material enters the metal material storage bin 8 and is then sent to the second vibrating screen 9 via the electric conveyor belt 1. The second vibrating screen 9 is a 100-mesh standard screen. Coarse particles that do not meet the standard are returned to the crusher for secondary crushing.

[0056] Positive and negative electrode materials enter the positive and negative electrode material separation equipment, and the positive and negative electrode materials are discharged from different outlets to achieve separation and collection of positive and negative electrode materials.

[0057] The working principle of the crusher 2: The material is crushed by two rollers rotating in opposite directions; the gap between the rollers can be adjusted within a specified range to control the size of the output particles.

[0058] The working principle of the knife crusher 3: The motor drives the main shaft and turbine to rotate at high speed. The turbine and the grinding blocks on the screen ring form a crushing and grinding pair with a compact structure. When the material enters the machine chamber from the feeding hopper, the material entering the machine chamber is tightly rubbed and strongly impacted on the inner edge of the turbine blades in the rotating airflow, and is further ground in the gap between the blades and the grinding blocks.

[0059] The working principle of the hammer crusher 6: The motor of the hammer crusher 6 drives the rotor to rotate at high speed in the crushing chamber. The material is fed into the machine from the upper feed port and is crushed by the impact, shearing and grinding action of the high-speed moving hammers. At the bottom of the rotor, there is a screen plate. The particles smaller than the screen hole size in the crushed material pass through the screen plate and are discharged. The coarse particles larger than the screen hole size are retained on the screen plate and continue to be hit and ground by the hammers until the particle size of the material reaches the required size.

[0060] Working principle of battery material separation device 7: A high-speed motor drives a vertical drive shaft to rotate via a transmission device. Material enters the classifier chamber through the feed inlet located at the top of the classifier chamber, and then falls onto the spreading plate through the upper and lower cones of the medium and coarse powder collecting cone and the powder passage pipe. The spreading plate rotates with the vertical drive shaft, and the material is evenly scattered in all directions under the action of inertial centrifugal force. Under the action of the high-speed airflow from the external fan entering the classifier chamber through the air inlet, the coarse particles in the material are thrown against the inner wall of the classifier chamber by inertial centrifugal force. After collision, they lose kinetic energy and slide down the wall, falling into the coarse powder collecting cone. The remaining particles are swept up by the rotating and rising airflow. When passing through the action area of ​​the large fan blade, some coarse powder particles are thrown against the inner wall of the classifier chamber by the impact of the large fan blade. After collision, they lose kinetic energy and slide down the wall, falling into the coarse powder collecting cone.

[0061] Vibrating screen equipment consists of a screen cover (usually equipped with a feed inlet), a screen frame (containing the screen mesh assembly), a drive unit (usually a vertical vibrating motor), a vibration isolation device (a set of support springs), and a base. The screen cover and screen frame are the vibrating parts, while the other parts are non-vibrating. The base also serves a supporting function. The screen frame is the main vibrating component of the rotary vibrating screen. The screen frame is made of rolled and welded sheet metal, with a retaining ring at both the top and bottom, and a flange ring inside the lower part for fixing the screen mesh assembly and other structures. When the vibrating screen is working, the eccentric blocks at different phases at the upper and lower ends of its power unit, namely the vibrating motor, generate a compound inertial force due to the high-speed placement. This inertial force forces the vibrating body of the screen to perform a compound rotational motion. Under the action of the vibration force, the screen frame continuously performs reciprocating motion, thereby driving the screen surface to perform periodic vibration. As a result, the material on the screen surface moves in a directional jumping motion along with the screen box. During this process, the material smaller than the screen aperture falls to the lower layer through the screen holes and becomes the undersize material. The material larger than the screen aperture is discharged from the discharge port after continuous jumping motion, thus completing the screening work.

[0062] Branch 2 - Lithium Battery Main Line Branch: All types of lithium batteries, including soft-pack, steel-shell, and cylindrical batteries, are directly fed into a closed steam reactor without the need for pre-deep crushing. The battery casing is automatically expanded and cracked by the high-temperature and high-pressure steam, simplifying the pre-crushing process.

[0063] The high-temperature and high-pressure steam is superheated steam with a temperature of 625~690℃ and a pressure of 0.99~2 MPa.

[0064] Step 03: Lead-acid solid-phase synergistic pre-reduction. The screened grid powder is thoroughly mixed with lead paste and kept at a constant temperature of 100~300℃ for 0.5~3h under normal pressure. PbO and PbSO4 are generated by the solid-phase oxidation-reduction reaction of elemental lead and lead dioxide. Then, hydrogen peroxide-sulfite compound reducing agent is added (the amount added is 0.2~0.5 times the mass of lead paste), and the reaction is carried out at a constant temperature of 10~40℃ with stirring for 10~120min. All high-valence lead components in the material are converted into divalent lead solid-phase mixture.

[0065] Step 04: Closed-ring leaching of lead-acetic acid-sodium acetate – desulfurization – preparation of high-purity PbO. Prepare a mixed leaching solution of acetic acid and sodium acetate (acetic acid to sodium acetate mass ratio 0.1~0.9, system pH controlled at 4~7, total leaching solution volume 5~20 times the lead paste mass). Add the divalent lead solid mixture to the acetic acid-sodium acetate mixed leaching solution, stir and leach at 15~80℃ for 30~180min, filter to remove clay and plastic impurities; add barium acetate to the filtrate (addition amount 0.2~1 times the lead paste mass), maintain the system pH at 4~8, 10~4. The reaction proceeds at 0℃ for 10-120 min, and sulfate and barium ions are directionally precipitated to obtain BaSO4 solid byproduct. The filtrate is a high-purity lead acetate solution. 0.5-5 mol / L sodium hydroxide / potassium hydroxide / ammonia water alkaline precipitant is added to the lead acetate solution, and precipitation is carried out at a constant temperature of 10-80℃ for 1-60 min. After filtration, multiple water washings, and drying, high-purity PbO product is obtained. All acetate mother liquor separated in the precipitation process is transferred back to the upstream acetic acid leaching process to realize a closed-loop circulation of reagents. The leaching wastewater is transported to a public integrated water treatment system.

[0066] Step 05: Lithium-ion battery superheated steam anaerobic pyrolysis. Softened water is generated into superheated steam at 625~690℃ and 0.99~2.0MPa by a steam generator, which is continuously introduced into a closed reactor to purge internal air, maintaining an anaerobic closed environment throughout the process. The pyrolysis is carried out at a constant temperature for 120~150 minutes. The high-temperature steam automatically expands and cracks the battery casing, the organic solvent in the electrolyte is vaporized by heating, and the lithium salt components dissolve in the condensed steam. The high-temperature mixed flue gas is led out to a condenser for cooling and condensation. The condensate is sent to an oil-water separator for stratified treatment: the upper organic phase is collected, stored, purified, and reused in production, while the lower layer, containing lithium and fluorine heavy metal wastewater, is uniformly transported to a public integrated water treatment system. After the pyrolysis is completed, the product is discharged, yielding a complete copper-aluminum casing and high-purity cathode powder. The purity of the lithium iron phosphate cathode powder is ≥90%, and the comprehensive recovery rate of solid metals is ≥80%. The combustible waste gases H2, CO, and CH4 generated by the pyrolysis are uniformly sent to a burner for complete combustion, and are discharged in a harmless and compliant manner.

[0067] Step 06: Supercritical CO2 extraction of lithium battery electrolyte. For lithium battery materials requiring complete recovery of electrolyte components: After discharge drying, the battery cells are broken down under an inert protective atmosphere and sent to a supercritical CO2 extraction device. The extraction conditions are controlled at 30~50℃ and 15~35MPa to achieve a supercritical fluid state, and the CO2 is continuously introduced into the extraction vessel until it is completely filled with supercritical CO2. The inlet and outlet valves are closed to form a completely closed and static system with no medium circulation. The system is statically soaked for 10~30 minutes. The high-pressure circulation pump is started to continuously and directionally circulate the supercritical CO2 in the vessel, entering a dynamic flushing condition for 10~50 minutes. After the CO2 medium is depressurized, it is circulated back for reuse, and the undecomposed components are separated by depressurization. The mixed electrolyte of lithium salt and carbonate can be directly prepared and reused, making it suitable for small-batch, fine-grained recycling scenarios.

[0068] Step 07: Centralized treatment of wastewater and exhaust gas. Wastewater from the lead-acid leaching process and lithium-containing wastewater from the lower layer of lithium battery oil-water separation are mixed and fed into a comprehensive water treatment system for stepwise precipitation and recovery of valuable metal salts such as lead, lithium, and fluoride. Unorganized exhaust gas from the lead-acid section and combustible exhaust gas from lithium battery cracking are collected and treated by unified combustion, and the exhaust gas is discharged in compliance with standards.

[0069] In integrated water treatment systems, agents such as sodium carbonate and sodium hydroxide are added to make... It is converted into lead carbonate (PbCO3) or lead hydroxide (Pb(OH)2) precipitate. Generally, the pH value is controlled at around 8-9, which can effectively precipitate and remove lead ions. The precipitate product can be obtained by filtration, washing and drying.

[0070] By adding reagents such as sodium carbonate and sodium phosphate, lithium ions are converted into lithium carbonate (Li2CO3) or lithium phosphate (Li3PO4) precipitates.

[0071] By adding agents such as calcium chloride and calcium hydroxide, fluoride ions react with calcium ions to form insoluble calcium fluoride (CaF2) precipitate. The fluoride removal rate can reach over 98%, and the concentration after treatment can be reduced to below 5 mg / L. The calcium fluoride obtained from precipitation can be further processed into fluoride salt products.

[0072] In summary: Lead-acid line process: full-charge stabilization pretreatment → closed crushing and screening → separate recovery of waste sulfuric acid; grid + lead paste mixed solid phase heating + reducing agent pre-reduction → acetic acid leaching and filtration → barium acetate desulfurization separation to produce BaSO4 by-product → alkali precipitation to prepare PbO finished product; acetate mother liquor is recycled to the acetic acid leaching process; lead-acid leaching wastewater is discharged into the public water treatment unit.

[0073] The main lithium battery production process is as follows: lithium battery discharge and drying → closed steam reactor at 625~690℃ anaerobic pyrolysis → condenser → oil-water separator; the upper organic solvent is stored, purified and reused, and the lower lithium-containing wastewater is collected and sent to a public water treatment system; the pyrolysis output yields complete metal shells and positive electrode powder; the pyrolysis exhaust gas is uniformly combusted to meet emission standards.

[0074] Lithium battery production line process: inert atmosphere breaking of discharge cells → supercritical CO2 extraction → collection and storage of complete electrolyte, with closed-loop circulation of CO2 medium.

[0075] Public collaborative unit: Lead acid leaching wastewater and lithium battery condensation wastewater are uniformly incorporated into the integrated water treatment system for centralized recovery of various heavy metal salts.

[0076] This application has the following beneficial effects:

[0077] The lead-acid material adopts a closed-loop wet process of full-charge pre-stabilization + solid-phase self-reduction acetic acid. It relies on the reduction of high-valence lead components in the lead paste by the metal element of the grid to greatly reduce the amount of external reducing agent added. The acetate mother liquor is recycled in a closed loop throughout the process to prepare high-purity PbO that can be directly used in the manufacture of battery cathodes. The by-product industrial-grade barium sulfate can be sold externally to increase the added value of the product.

[0078] The lithium battery materials are produced using a closed, oxygen-free superheated steam pyrolysis process at 625~690℃, which completely eliminates the risk of electrolyte spontaneous combustion and toxic fumes. After pyrolysis, the shell, copper-aluminum current collector, and positive electrode active powder are structurally intact, with a solid metal recovery rate of ≥80% and a purity of up to 90% for lithium iron phosphate positive electrode powder.

[0079] A dual-electrolyte recovery parallel process is set up: large-scale industrial metal recovery uses steam cracking to separate the electrolyte organic solvent; for small-batch, fine electrolyte regeneration needs, a supercritical CO2 extraction branch line is added, and the two processes can be flexibly switched to adapt to different incoming material conditions.

[0080] The condensate wastewater generated by the two types of battery production systems is uniformly collected into a comprehensive water treatment unit for centralized treatment, and valuable components such as lead salt, lithium salt, and fluoride salt are recovered in stages; the waste gas from the entire process is uniformly collected and incinerated to meet emission standards. The amount of waste generated is far lower than that of the two independent production lines, making it green and low-carbon, and suitable for continuous industrial mass production.

[0081] The organic solvent in the upper layer of the oil-water separation by steam cracking can be purified and reused in production; supercritical CO2 extraction can completely retain the lithium salt and carbonate solvent components of LiPF6, realize high-value regeneration of electrolyte, and significantly improve the overall economic benefits of recycling waste batteries.

[0082] This invention adopts a dual-line parallel collaborative processing architecture, with lead-acid and lithium battery production lines sharing common equipment for condensation, oil-water separation, integrated water treatment, and tail gas incineration, reducing redundant equipment investment and plant footprint. The lead-acid recovery route relies on a grid-type elemental lead solid-phase self-reduction + barium acetate desulfurization closed-loop wet process system, with low external reducing agent dosage and significantly reduced acetic acid reagent consumption through mother liquor recycling, producing high-purity PbO at low cost, and achieving external sales value-added from the by-product barium sulfate; the lithium battery adopts a dual-process parallel route: high-temperature anaerobic steam cracking is suitable for large-scale continuous metal recovery, relying on high-temperature steam for automatic shell breaking, completely preserving metal and cathode powder, and simultaneously separating organic solvents; the supercritical CO2 extraction branch is adapted for small-batch fine production, completely preserving the lithium salt solvent components of the electrolyte, and achieving electrolyte regeneration; the waste liquid and waste gas generated by the two types of waste batteries are treated centrally and collaboratively, simultaneously recovering multiple valuable materials such as lead, lithium, barium, and organic solvents. The entire process is streamlined, the reagent recycling rate is high, and the emissions of waste gas, wastewater, and solid waste are significantly reduced, taking into account both environmental benefits and resource recovery economic benefits.

[0083] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A combined treatment method for the wet recovery of waste lead-acid and lithium batteries to prepare PbO and intact electrolyte, characterized in that, Includes the following steps: Step 01: Incoming material classification, sorting, and pre-processing; Step 02: Pre-treatment by splitting the crushing and screening into two lead-acid branches and a lithium battery main line branch; Step 03: Lead-acid solid-phase synergistic pre-reduction; Step 04: Leaching of lead-acetic acid through closed-ring desulfurization and preparation of high-purity PbO; Step 05: Lithium-ion battery superheated steam anaerobic pyrolysis; Step 06: Supercritical CO2 extraction of lithium battery electrolyte; Step 07: Centralized treatment of wastewater and exhaust gas.

2. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 1, characterized in that, In step 01, the waste batteries are sorted manually or by equipment into two separate material receiving channels: lead-acid battery packs and lithium-ion battery packs. The pretreatment of lead-acid battery packs involves charging individual lead-acid cells at a constant voltage of 2.45V and a current-limited rate of 0.02C for 4 to 10 hours to stably convert the active material inside the plates into Pb / PbO2. The pretreatment of lithium-ion battery packs involves discharging the lithium-ion batteries uniformly until the individual cell voltage is <1V, rinsing the surface electrolyte with clean water, and then drying them for later use.

3. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 2, characterized in that, In step 02, the lead-acid branch: the lead-acid battery that has completed full-charge pretreatment is sent to the crusher for dismantling, and multi-stage screening achieves three-phase separation: the waste sulfuric acid liquid phase is separated and collected separately for resource recycling, the remaining metal grid and lead paste solid phase are mixed, crushed and passed through a 100-mesh standard sieve, and the coarse particles that do not meet the standard are returned to the crusher for secondary crushing. Lithium battery main line branch: Various types of lithium batteries are directly fed into a closed steam reactor, where the battery casings automatically expand and crack due to the superheated steam.

4. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 3, characterized in that, In step 03, the sieved grid powder is thoroughly mixed with lead paste and kept at a constant temperature of 100~300℃ under normal pressure for 0.5~3 hours. PbO and PbSO4 are generated by the solid-phase oxidation-reduction reaction of elemental lead and lead dioxide. Then, hydrogen peroxide-sulfite compound reducing agent is added and stirred at a constant temperature of 10~40℃ for 10~120 minutes to convert all high-valence lead components in the material into a divalent lead solid-phase mixture. The amount of hydrogen peroxide-sulfite compound reducing agent added is 0.2~0.5 times the mass of lead paste.

5. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 4, characterized in that, In step 04, a mixed leaching solution of acetate and sodium acetate is prepared, with a mass ratio of acetate to sodium acetate of 0.1 to 0.9, and the pH of the system is controlled at 4 to 7. The total amount of leaching solution used is 5 to 20 times the mass of lead paste. The divalent lead solid mixture is placed into the mixed leaching solution of acetate and sodium acetate and leached by stirring at 15 to 80°C for 30 to 180 minutes. The solution is then filtered to remove clay and plastic impurities. Barium acetate is added to the filtrate, with the amount of barium acetate added being 0.2 to 1 times the mass of lead paste. The pH of the system is maintained at 4 to 8, and the reaction is carried out at 10 to 40°C for 10 to 120 minutes. Sulfate and barium ions are directionally precipitated and separated to obtain BaSO4 solid byproduct. The filtrate is a high-purity lead acetate solution. Add 0.5~5 mol / L sodium hydroxide / potassium hydroxide / ammonia water alkaline precipitant to the lead acetate solution, precipitate at a constant temperature of 10~80℃ for 1~60 min, filter, wash with water multiple times and dry to obtain high-purity PbO product. All acetate mother liquor separated in the precipitation process is transported back to the upstream acetic acid leaching process, and the leaching wastewater is transported to the public integrated water treatment system.

6. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 5, characterized in that, In step 05, softened water is converted into superheated steam at 625~690℃ and 0.99~2.0MPa by a steam generator, and continuously introduced into a closed reactor to purge internal air. The reactor is then subjected to constant-temperature pyrolysis for 120~150 minutes. The high-temperature steam automatically expands and cracks the battery casing, the organic solvent in the electrolyte vaporizes upon heating, and the lithium salt components dissolve in the condensed steam. The high-temperature mixed flue gas is then discharged to a condenser for cooling and condensation. The condensate is sent to an oil-water separator for stratified treatment: the upper organic phase is collected, stored, purified, and reused in production; the lower layer, containing lithium and fluorine heavy metal wastewater, is uniformly transported to a public integrated water treatment system. After pyrolysis, the material is discharged, yielding a complete copper-aluminum casing and high-purity cathode powder. The combustible waste gases generated by pyrolysis, H2, CO, and CH4, are uniformly sent to a burner for complete combustion.

7. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 6, characterized in that, In step 06, for lithium-ion battery materials requiring complete recovery of electrolyte components: the discharged and dried battery cells are broken down under an inert protective atmosphere and sent to a supercritical CO2 extraction device; the extraction conditions are controlled at 30~50℃ and 15~35MPa to reach a supercritical fluid state, and the CO2 is continuously introduced into the extraction vessel until the vessel is completely filled with supercritical CO2; the fluid inlet and outlet valves are closed to form a completely closed and static system with no medium circulation, and the system is statically soaked for 10~30 minutes; the high-pressure circulation pump is started to continuously and directionally circulate the supercritical CO2 in the vessel, entering a dynamic flushing condition for 10~50 minutes; the CO2 medium is depressurized and recycled, and the undecomposed CO2 is separated by depressurization. A mixed electrolyte of lithium salt and carbonate.

8. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 7, characterized in that, In step 07, the wastewater generated from the lead-acid leaching process and the lithium-containing wastewater from the lower layer of the lithium battery oil-water separation are mixed and fed into the integrated water treatment system. The valuable metal salts, such as lead salt, lithium salt, and fluoride salt, are recovered through stepwise precipitation. The combustible waste gas from the lithium battery cracking is collected and then treated by unified combustion.

9. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 8, characterized in that, In step 07, sodium carbonate and sodium hydroxide are added to the integrated water treatment system to... It is converted into lead carbonate or lead hydroxide precipitate; the pH value is controlled at 8-9, and lead ions can be effectively precipitated and removed. The precipitate product can be obtained as lead salt product after filtration, washing and drying. By adding sodium carbonate or sodium phosphate, lithium ions are converted into lithium carbonate or lithium phosphate precipitate. By adding calcium chloride and calcium hydroxide, fluoride ions react with calcium ions to form an insoluble calcium fluoride precipitate.

10. The method for the combined treatment of waste lead-acid and lithium battery synergistic wet recycling to prepare PbO and intact electrolyte according to claim 9, characterized in that, In step 01, the crusher includes a rolling crusher (2), a knife crusher (3), a plastic material separation and collection device (4), a hammer crusher (6), a battery material separation device (7), a cyclone separator (10), a metal material storage bin (8), and a second vibrating screen (9). An electric conveyor belt (1) is provided between the crusher (2) and the knife crusher (3). The material after being crushed by the crusher (2) is sent to the knife crusher (3) via the electric conveyor belt (1). After being crushed by the knife crusher (3), the material is sent to the plastic material separation and collection device (4). The plastic material separation and collection device (4) is connected to the plastic material storage bin (41) and the hammer crusher (6) respectively. The plastic part is sucked into the plastic material storage bin (41) by the vacuum pump (14). The dust enters the dust collection device (5). The remaining part is sent to the hammer crusher (6) for further crushing. The battery material separation device (7) after being crushed by the hammer crusher (6) has metal material entering the metal material storage bin (8). After passing through the electric conveyor belt (1), it is sent to the second vibrating screen (9). The second vibrating screen (9) is a 100-mesh standard screen. The coarse particles that do not meet the standard are returned to the crusher for secondary crushing. Positive and negative electrode materials enter the positive and negative electrode material separation equipment, and the positive and negative electrode materials are discharged from different outlets to achieve separation and collection of positive and negative electrode materials.

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