A sorting method of waste battery crushing material

Abstract

The present application belongs to the technical field of waste battery processing, and particularly relates to a sorting method of waste battery crushing materials. Through the innovative dry-wet method coordination strategy, especially the core wet process design for fine particle materials, the present application effectively solves the key problems in the prior art, such as impure copper-aluminum separation, black powder loss pollution, wastewater treatment difficulty, low fine particle sorting efficiency and the like, and realizes high-purity, high-recovery, low-water consumption, low-pollution, low-cost, safe and reliable sorting of waste battery crushing materials.

Description

Technical Field

[0001] This invention belongs to the field of waste battery processing technology, specifically relating to a sorting method for crushed waste battery materials. Background Technology

[0002] The existing waste battery crushing and pulverizing sorting process mainly faces the following technical challenges:

[0003] (1) Incomplete separation of copper and aluminum: Dry separation (such as air separation and eddy current separation) has low separation efficiency for copper foil and aluminum foil fragments with flat shape and similar density, resulting in high aluminum residue in copper powder (>5%) and high copper residue in aluminum powder (>3%). The purity of the products is difficult to meet the requirements for recycling (such as copper powder requires >98% and aluminum powder requires >95%).

[0004] (2) Metal loss due to black powder entrainment: Although traditional wet separation (such as flotation) can improve the copper-aluminum separation effect to a certain extent, there is a problem that black powder (electrode active material) is entrained into copper / aluminum products by water flow or lost with wastewater, resulting in a decrease in the recovery rate of valuable metals (such as lithium, cobalt, nickel, manganese) (usually the loss rate is >5%).

[0005] (3) High wastewater pollution and treatment costs: Wet sorting requires a large amount of water resources and produces wastewater containing heavy metals, organic matter (PVDF decomposition products of binder) and electrolyte residues (COD>5000mg / L, total heavy metals>100mg / L). Subsequent treatment processes are complex and costly (accounting for about 20~30% of the total treatment cost).

[0006] (4) Low efficiency of fine particle sorting: The fine particles (<0.5mm) produced after crushing and grinding have a sharp decrease in sorting efficiency by existing dry sorting methods, and wet sorting is also prone to forming mud layers that interfere with sorting. Summary of the Invention

[0007] The purpose of this invention is to provide a sorting method for crushed waste batteries. The method provided by this invention aims to solve the key technical problems existing in the crushing and sorting process of waste lithium batteries, such as low purity of copper-aluminum separation, low recovery rate of black powder metal, large amount of wastewater generation, and difficulty in sorting fine particles.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a method for sorting waste battery shredded material, comprising the following steps:

[0010] The waste battery shreds are subjected to primary dry sorting to obtain light components and heavy components; the heavy components include copper, aluminum and black powder.

[0011] The heavy components are subjected to two-stage dry separation to obtain black-rich powder and copper-aluminum-rich mixture.

[0012] The copper-aluminum mixture is subjected to particle size classification to obtain coarse copper-aluminum and fine copper-aluminum; the particle size of the coarse copper-aluminum is ≥0.8mm; the particle size of the fine copper-aluminum is <0.8mm.

[0013] The coarse copper and aluminum particles are subjected to a three-stage dry separation process to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder.

[0014] The fine copper and aluminum particles were subjected to electrochemical pretreatment, composite chelation reaction and pulsed microbubble flotation in sequence to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0015] Preferably, the conditions and parameters for the primary dry separation include: using an airflow separator, an air velocity of 5~8 m / s, and an angle of 15~25° between the feed inlet and the horizontal plane.

[0016] Preferably, the conditions and parameters for the secondary dry separation include: using an eddy current separator with a rotor speed of 2800~3200 rpm; the magnetic pole arrangement is alternating N and N poles with a pole number of 8 and a pole arc coefficient of 0.75; the belt speed is 1.8~2.2 m / s; and the material layer thickness is 3~8 mm.

[0017] Preferably, after obtaining the black-rich powder, the method further includes finely classifying the black-rich powder to obtain fine powder containing metal and black powder.

[0018] The fine classification is performed using an air classifier or a vibrating screen.

[0019] The parameters for using an air classifier include: classifier speed of 2500~3500 rpm, inlet pressure of 0.4~0.6 MPa, and cutting particle size D50 of 0.25~0.35 mm;

[0020] The parameters for using a vibrating screen include: vibration frequency of 25~35Hz, amplitude of 2~4mm, and screen mesh size of 400 mesh for the upper layer and 200 mesh for the lower layer.

[0021] Preferably, the conditions and parameters for the three-stage dry separation include: using a high-voltage electrostatic separator with a voltage of 35~50kV, a drum speed of 80~120rpm, a distance of 60~80mm between the corona electrode and the drum, a distance of 120~150mm between the static electrode and the drum, and an ambient relative humidity of <45%.

[0022] Preferably, the large-particle high-purity copper powder has a copper content of ≥99.5% and an aluminum content of ≤0.3%; the large-particle high-purity aluminum powder has an aluminum content of ≥99.0% and a copper content of ≤0.2%.

[0023] Preferably, the electrochemical pretreatment process includes: mixing the fine copper-aluminum particles with the electrolyte and then performing electrochemical treatment;

[0024] The electrolyte is a citric acid solution with a mass concentration of 0.5%; the solid-liquid ratio of the mixed solution is 1:8.

[0025] The electrochemical treatment conditions include: the anode is a titanium-based ruthenium-iridium coated electrode, and the cathode is a stainless steel cathode; a DC pulse power supply is used with a voltage of 0.8~1.2V, a frequency of 20~50Hz, a duty cycle of 40~60%, and a treatment time of 3~5min; the electrochemical pretreatment is carried out under stirring conditions, and the stirring speed is 120rpm.

[0026] Preferably, the process of the composite chelation reaction includes: mixing the electrochemically pretreated system and the chelating agent solution to carry out the composite chelation reaction;

[0027] The chelating agent solution comprises the following components in weight percentage: 0.5-1.5% organic acid, 0.05-0.2% mercaptobenzotriazole, 0.1-0.5% nano-silica sol, 0.01-0.1% sodium polyaspartate, and the balance being water;

[0028] The conditions for the composite chelation reaction include: a temperature of 35~45℃, a pH value of 3.0~4.0, a reaction time of 8~12min, and the composite chelation reaction is carried out under stirring conditions with a stirring speed of 80~100rpm.

[0029] Preferably, the pulsed microbubble flotation process includes: mixing the system obtained from the composite chelation reaction with the reagent, and then performing pulsed microbubble flotation;

[0030] The reagent includes a copper scavenger and a foaming agent; the copper scavenger is sodium isopropyl xanthate, and the dosage of the copper scavenger is 20~40 g / t; the foaming agent is methyl isobutyl methanol, and the dosage of the foaming agent is 10~20 g / t.

[0031] The reagent is added in two stages, with half added before flotation and the other half added during the middle of flotation.

[0032] The conditions and parameters for pulsed microbubble flotation include: using a self-priming microbubble flotation machine, a pulse pressure of 0.2~0.4MPa, a pulse frequency of 3~8Hz, a bubble size of 30~100μm, a microbubble ratio of >70%, and a flotation time of 5~8min.

[0033] Preferably, the copper content in the small-particle high-purity copper powder is ≥99.3% and the aluminum content is ≤0.35%; the aluminum content in the small-particle high-purity aluminum powder is ≥98.5% and the copper content is ≤0.25%.

[0034] This invention provides a method for sorting waste battery crushed material, comprising the following steps: performing primary dry sorting on the waste battery crushed material to obtain light components and heavy components; the heavy components include copper, aluminum, and black powder; performing secondary dry sorting on the heavy components to obtain black powder-rich material and copper-aluminum-rich mixture; performing particle size classification on the copper-aluminum-rich mixture to obtain coarse copper-aluminum particles and fine copper-aluminum particles; the coarse copper-aluminum particles have a particle size ≥ 0.8 mm; the fine copper-aluminum particles have a particle size < 0.8 mm; performing tertiary dry sorting on the coarse copper-aluminum particles to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder; and sequentially performing electrochemical pretreatment, composite chelation reaction, and pulsed microbubble flotation on the fine copper-aluminum particles to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0035] To address the shortcomings of existing technologies, such as strong alkaline corrosion, low value of aluminum products, black powder pollution loss, and difficulty in wastewater treatment, as well as the more widespread problems of impure copper-aluminum separation in dry separation, high water consumption and wastewater in wet separation, and difficulty in fine particle separation, this invention proposes an innovative dry-wet co-sorting process, aiming to:

[0036] (1) Significantly improve the purity of copper-aluminum separation: the aluminum residue in the target copper powder is <1%, and the copper residue in the aluminum powder is <1%, meeting the requirements of high-value regeneration.

[0037] (2) Maximize the recovery of black powder and reduce pollution: The black powder recovery rate is >98%, and the copper and aluminum impurities in the black powder are low (<1%), which is conducive to subsequent hydrometallurgical purification.

[0038] (3) Significantly reduce water consumption and wastewater treatment load: Compared with the traditional wet process, it reduces fresh water consumption by more than 80%, and reduces wastewater generation and pollutant concentration by more than 70%.

[0039] (4) High-efficiency sorting of fine particles: It has a good sorting effect on fine particles <0.5mm.

[0040] (5) Process safety, environmental protection and economy: Avoid the use of highly corrosive chemicals, reduce equipment requirements and safety risks, and reduce overall operating costs. Attached Figure Description

[0041] Figure 1 This is a schematic flowchart of the dry separation section in the sorting method provided by the present invention;

[0042] Figure 2 This is a schematic diagram of the wet separation section in the sorting method provided by the present invention. Detailed Implementation

[0043] This invention provides a method for sorting waste battery shredded material, comprising the following steps:

[0044] The waste battery shreds are subjected to primary dry sorting to obtain light components and heavy components; the heavy components include copper, aluminum and black powder.

[0045] The heavy components are subjected to two-stage dry separation to obtain black-rich powder and copper-aluminum-rich mixture.

[0046] The copper-aluminum mixture is subjected to particle size classification to obtain coarse copper-aluminum and fine copper-aluminum; the particle size of the coarse copper-aluminum is ≥0.8mm; the particle size of the fine copper-aluminum is <0.8mm.

[0047] The coarse copper and aluminum particles are subjected to a three-stage dry separation process to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder.

[0048] The fine copper and aluminum particles were subjected to electrochemical pretreatment, composite chelation reaction and pulsed microbubble flotation in sequence to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0049] This invention performs primary dry sorting on crushed waste batteries to obtain light and heavy components.

[0050] In this invention, the shredded waste battery material preferably includes black powder (positive and negative electrode active materials), copper foil fragments, aluminum foil fragments, separator fragments, and plastic fragments. In this invention, the particle size of the shredded waste battery material is preferably 0.1~20mm. In this invention, the waste battery is preferably a waste lithium battery, specifically a waste lithium iron phosphate battery or a waste ternary lithium battery. This invention does not impose any special limitations on the source of the shredded waste battery material; any source well known to those skilled in the art can be used. Specifically, it can involve sequentially pre-discharging, disassembling, coarsely crushing, and finely crushing the waste batteries.

[0051] In this invention, the preferred conditions for the primary dry separation include: using an airflow separator with a wind speed of 5-8 m / s and an angle of 15-25° (i.e., airflow angle) between the feed inlet and the horizontal plane; the airflow separator includes an upper light component outlet and a lower heavy component collection area; the upper light component outlet is equipped with a vortex stabilizing plate with an opening ratio of 40%; the lower heavy component collection area is equipped with stepped baffles, which are three-stage stepped baffles with a height difference of 30 mm between each stage.

[0052] In this invention, the light component preferably includes membrane fragments and plastic fragments, and the heavy component preferably includes black powder, copper foil fragments and aluminum foil fragments.

[0053] In this invention, the primary dry separation utilizes the differences in material density and aerodynamic properties for separation. In a controlled airflow field, lighter materials (diaphragms, plastics) are carried upwards by the airflow to become light components, while heavier materials (copper, aluminum, black powder) settle or follow a specific path to become heavy components. In this invention, the separation efficiency of the primary dry separation is preferably >98%, and the residual amount of black powder in the light components is preferably <2%.

[0054] After obtaining the recombinant components, the present invention performs two-stage dry separation on the recombinant components to obtain black-rich powder and copper-aluminum-rich mixture.

[0055] In this invention, the preferred parameters for the two-stage dry separation include: using an eddy current separator with a rotor speed of 2800~3200 rpm (corresponding to a magnetic field frequency of 45~55 Hz); alternating N and N poles with 8 poles and a pole arc coefficient of 0.75; a belt speed of 1.8~2.2 m / s (matching the rotor speed to ensure sufficient force on the conductor); and a material layer thickness of 3~8 mm.

[0056] In this invention, the two-stage dry sorting utilizes the principle that conductive materials generate eddy currents and experience repulsive forces in an alternating magnetic field. A high-speed rotating permanent magnet rotor generates a high-frequency alternating magnetic field. When conductive materials (copper, aluminum) pass through, eddy currents are induced. The magnetic field generated by the eddy currents interacts with the original magnetic field, producing a repulsive force (Lorentz force), causing the conductive materials to be thrown forward and become conductive material. Non-conductive materials (black powder, residual plastic) are not subject to magnetic force or experience very little force, and fall into the non-conductive hopper by gravity or inertia, becoming black powder-rich material.

[0057] In this invention, the residual rate of copper and aluminum in the black powder is preferably <3%, and the content of copper and aluminum in the copper-aluminum mixture is preferably >97%.

[0058] After obtaining the black-rich powder, the present invention preferably further includes fine grading of the black-rich powder to obtain fine powder containing metal and black powder.

[0059] In this invention, the fine classification is preferably performed using an air classifier or a vibrating screen.

[0060] In this invention, the preferred parameters for using an air classifier include: a classifier speed of 2500~3500 rpm, an inlet pressure of 0.4~0.6 MPa, and a cutting particle size D50 of 0.25~0.35 mm.

[0061] In this invention, the preferred parameters for using a vibrating screen include: a vibration frequency of 25~35Hz (corresponding to a rotation speed of 1500~2100rpm), an amplitude of 2~4mm, and a screen mesh size of 400 mesh (0.038mm) for the upper layer and 200 mesh (0.075mm) for the lower layer.

[0062] In this invention, when the throughput of the black powder is >2 t / h, an air classifier is preferably used for fine classification; when the throughput is <2 t / h, a vibrating screen is preferably used for fine classification. In this invention, the metal-containing fine powder is preferably recycled to the secondary dry separation process or mixed with subsequently obtained fine copper and aluminum particles for further processing.

[0063] In this invention, after fine grading, qualified black powder that meets the purity requirements (usually with a particle size <0.3mm and few metal impurities) can be separated, and the metal-containing fine powder containing incompletely separated micro-metal fragments (mainly copper and aluminum) can be separated for further processing.

[0064] After obtaining the copper-rich aluminum mixture, the present invention performs particle size classification on the copper-rich aluminum mixture to obtain coarse copper-aluminum and fine copper-aluminum.

[0065] In this invention, particle size classification is preferably performed using a vibrating screen. This invention does not impose any particular limitation on the particle size classification process; any process well-known to those skilled in the art can be used.

[0066] In this invention, the copper-aluminum mixture is divided into coarse-grained copper and aluminum (particle size ≥ 0.8 mm) and fine-grained copper and aluminum (particle size < 0.8 mm). In the coarse-grained material, the copper and aluminum fragments are relatively independent and easily separated by dry methods. In the fine-grained material, the copper and aluminum fragments are more likely to entangle and become mixed together, making dry separation difficult.

[0067] After obtaining the coarse copper and aluminum particles, the present invention performs three-stage dry separation to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder.

[0068] In this invention, the preferred conditions for the three-stage dry separation include: using a high-voltage electrostatic separator with a voltage of 35~50kV, a drum rotation speed of 80~120rpm, a distance of 60~80mm between the corona electrode and the drum, a distance of 120~150mm between the static electrode and the drum, and an ambient relative humidity of <45%.

[0069] In this invention, the copper content in the large-particle high-purity copper powder is preferably ≥99.5%, and the aluminum content is preferably ≤0.3%; the aluminum content in the large-particle high-purity aluminum powder is preferably ≥99.0%, and the copper content is preferably ≤0.2%.

[0070] In this invention, the three-stage dry sorting utilizes the difference in electrical conductivity of the materials. After being charged by corona electrodes, the materials fall onto a rotating, grounded drum. Good conductors (copper) have their charge dissipated rapidly and are removed from the drum earlier due to centrifugal force and gravity. Non-good conductors (aluminum) have their charge dissipated more slowly and are carried a longer distance by the drum before being peeled off by brushes or scrapers.

[0071] After obtaining the fine-grained copper and aluminum, the present invention sequentially performs electrochemical pretreatment, composite chelation reaction and pulsed microbubble flotation (i.e., wet synergistic treatment) on the fine-grained copper and aluminum to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0072] In this invention, the electrochemical pretreatment process preferably includes: mixing the fine-grained copper-aluminum particles and the electrolyte, followed by electrochemical treatment; the electrolyte is preferably a citric acid solution, and the mass concentration of the citric acid solution is preferably 0.5%; the solid-liquid ratio of the mixed solution is preferably 1:8; the electrochemical treatment conditions preferably include: the anode is a titanium-based ruthenium-iridium coated electrode (size 200). The cathode is 300mm thick and made of stainless steel. A DC pulse power supply is used with a voltage of 0.8~1.2V, a frequency of 20~50Hz, a duty cycle of 40~60%, and a processing time of 3~5min. The electrochemical pretreatment is carried out under stirring conditions, and the stirring speed is 120rpm.

[0073] In this invention, the preferred reaction occurring during the electrochemical pretreatment process is:

[0074] Cathode (aluminum foil): Al2O3 + 6H + +6e - →2Al 3+ +3H2O (reduction of oxide layer);

[0075] Anode (solution): 2H₂O - 4e - →O2+4H + (Generate active H) + ).

[0076] In this invention, electrochemical pretreatment can precisely, gently, and controllably "activate" the surface of aluminum foil, creating optimal conditions for subsequent chelation reactions while ensuring that the copper foil remains largely unaffected. The electrochemical pretreatment is not for dissolving large amounts of aluminum, but rather for precisely controlling and breaking its passivation layer to create an activated surface, making the originally chemically inert aluminum foil easier to be treated by subsequent agents. Specifically: (1) Aluminum foil naturally forms a dense, chemically stable, and poorly conductive aluminum oxide film (approximately 5-10 nm thick) in the air. This film prevents the internal aluminum atoms from effectively contacting the chelating agent in the solution. The electrochemical pretreatment reaction electrochemically dissolves the insoluble aluminum oxide film, exposing the underlying fresh and highly active metallic aluminum atoms; (2) The exposed fresh aluminum atoms are extremely active in a weakly acidic citric acid environment and will react with H in the solution. + A reaction occurs, producing trace amounts of Al. 3+And generate hydrogen. This process will form a large number of micro-corrosion pits and cracks on the surface of aluminum foil. These areas become the "activation points" for subsequent chelating agent attack, significantly increasing the reaction surface area; (3) After electrochemical activation, the surface of aluminum foil changes from the original hydrophobic / passivated state to hydrophilic and positively charged (due to the adsorption of Al 3+ This state makes it more likely to remain in the aqueous phase (tailings) during subsequent flotation processes, rather than rising with the bubbles.

[0077] In this invention, the process of the composite chelation reaction preferably includes: mixing the electrochemically pretreated system and the chelating agent solution to carry out the composite chelation reaction.

[0078] In this invention, the chelating agent solution preferably comprises the following components in the following mass percentages: 0.5-1.5% organic acid, 0.05-0.2% mercaptobenzotriazole (MBT), 0.1-0.5% nano-silica sol, 0.01-0.1% sodium polyaspartate, and the balance being water.

[0079] In this invention, the organic acid preferably includes citric acid, and the organic acid is preferably used as the main chelating agent.

[0080] In this invention, the mercaptobenzotriazole (MBT) is a copper-specific inhibitor that can form a nanoscale polymer film on the surface.

[0081] In this invention, the particle size of silica in the nano-silica sol is preferably 50 nm; the specific surface area of ​​the nano-silica sol is preferably >300 m². 2 / g; the nano silica sol is preferably pretreated before use, the pretreatment preferably includes: activating by mixing the nano silica sol with hydrochloric acid solution, the concentration of the hydrochloric acid solution is preferably 0.1 mol / L, and the activation time is preferably 30 min; the nano silica sol serves as a carrier, loading other chelating agents for directional adsorption at aluminum cracks.

[0082] In this invention, the sodium polyaspartate serves as a dispersant, which can prevent the agglomeration of nano-silica sol particles.

[0083] In this invention, the preferred conditions for the composite chelation reaction include: a temperature of 35-45°C, a pH of 3.0-4.0, and a reaction time of 8-12 min. The composite chelation reaction is preferably carried out under stirring conditions, with a stirring speed of 80-100 rpm.

[0084] In this invention, the composite chelation reaction is based on electrochemical activation, selectively and differentially modifying the surface physicochemical properties of copper and aluminum. MBT protects and hydrophobizes the copper foil, while citric acid and nano-silica sol work synergistically to hydrophilize the aluminum foil, maximizing their behavioral differences in subsequent flotation.

[0085] In this invention, the pulsed microbubble flotation process preferably includes: mixing the system obtained from the composite chelation reaction with the reagent, and performing pulsed microbubble flotation; the reagent preferably includes a copper trapping agent and a frother.

[0086] In this invention, the copper capture agent is preferably sodium isopropyl xanthate, and the dosage of the copper capture agent is preferably 20-40 g / t; the frother is preferably methyl isobutyl methanol (MIBC), and the dosage of the frother is preferably 10-20 g / t. In this invention, the reagent is preferably added in two parts, with half added before flotation and the other half added during the middle of flotation.

[0087] In this invention, the preferred conditions for pulsed microbubble flotation include: using a self-priming microbubble flotation machine, a pulse pressure of 0.2~0.4MPa, a pulse frequency of 3~8Hz, a bubble size of 30~100μm, a microbubble ratio of >70%, and a flotation time of 5~8min.

[0088] In this invention, after the pulse microbubble flotation, the process preferably includes dehydrating and drying the obtained copper concentrate and aluminum concentrate separately. The copper concentrate is preferably dehydrated using high-frequency eddy current dehydration, and the aluminum concentrate is preferably dehydrated and dried using low-temperature vacuum drying. This invention does not impose any particular limitations on the high-frequency eddy current dehydration and low-temperature vacuum drying processes; any dry material that can be obtained is acceptable.

[0089] In this invention, the copper content in the small-particle high-purity copper powder is preferably ≥99.5%, and the aluminum content is preferably ≤0.3%; the aluminum content in the small-particle high-purity aluminum powder is preferably ≥99.0%, and the copper content is preferably ≤0.2%.

[0090] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0091] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0092] Example 1

[0093] Taking waste lithium iron phosphate batteries as an example, the waste lithium iron phosphate batteries are pre-discharged, disassembled, coarsely crushed and finely crushed in sequence to obtain crushed material; the crushed material includes black powder (positive and negative electrode active materials), copper foil fragments, aluminum foil fragments, separator fragments and plastic fragments; the particle size is 0.1mm~15mm;

[0094] 2 kg of crushed material was subjected to primary dry separation to obtain light and heavy components. The conditions for primary dry separation were as follows: an air classifier was used, the wind speed was 6.5 m / s, and the angle between the feed inlet and the horizontal plane was 20° (i.e., the airflow angle). The air classifier included an upper light component outlet and a lower heavy component collection area. The upper light component outlet was equipped with a vortex stabilizing plate with an opening ratio of 40%. The lower heavy component collection area was equipped with stepped baffles, which consisted of three levels with a height difference of 30 mm between each level.

[0095] The obtained heavy components were subjected to two-stage dry separation to obtain black-rich powder and copper-aluminum-rich mixture. The conditions and parameters of the two-stage dry separation were as follows: eddy current separator was used, rotor speed was 3000 rpm (corresponding to magnetic field frequency of 50 Hz); magnetic pole arrangement was alternating N-S poles, number of poles was 8, pole arc coefficient was 0.75; belt speed was 2.0 m / s; material layer thickness was 5 mm; the residual copper and aluminum content in the black-rich powder was 2.8%, and the copper and aluminum content in the copper-aluminum-rich mixture was 97.5%.

[0096] The obtained black powder was finely classified to obtain fine powder containing metal and black powder. The fine classification was carried out using an air classifier with the following parameters: classifier speed of 3000 rpm, air pressure of 0.5 MPa, and cutting particle size D50 of 0.3 mm.

[0097] The obtained copper-aluminum mixture was subjected to particle size classification using a vibrating screen to obtain coarse copper-aluminum particles and fine copper-aluminum particles; the particle size of the coarse copper-aluminum particles was ≥0.8mm; the particle size of the fine copper-aluminum particles was <0.8mm.

[0098] The obtained coarse copper and aluminum particles were subjected to a three-stage dry separation process to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder. The conditions for the three-stage dry separation were as follows: a high-voltage electrostatic separator was used with a voltage of 40kV, a drum speed of 100rpm, a distance of 70mm between the corona electrode and the drum, a distance of 135mm between the electrostatic electrode and the drum, and an ambient relative humidity of 40%. The obtained large-particle high-purity copper powder contained 99.6% copper and 0.25% aluminum; the large-particle high-purity aluminum powder contained 99.1% aluminum and 0.15% copper.

[0099] The obtained fine copper and aluminum particles were subjected to electrochemical pretreatment, composite chelation reaction and pulse microbubble flotation in sequence to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0100] The electrochemical pretreatment process includes: mixing the fine-grained copper-aluminum particles with an electrolyte, followed by electrochemical treatment; the electrolyte is a citric acid solution with a mass concentration of 0.5%; the solid-liquid ratio of the resulting mixture is 1:8; the electrochemical treatment parameters are: the anode is a titanium-based ruthenium-iridium coated electrode (size 200). The cathode is a stainless steel cathode (300mm); a DC pulse power supply is used with a voltage of 1.0V, a frequency of 30Hz, a duty cycle of 50%, and a processing time of 4min. The electrochemical pretreatment is carried out under stirring conditions, and the stirring speed is 120rpm.

[0101] The electrochemically pretreated system was mixed with a chelating agent solution to carry out a composite chelation reaction. The chelating agent solution included 1.0% citric acid, 0.1% mercaptobenzotriazole, 0.3% nano-silica sol, 0.05% sodium polyaspartate, and the balance being water. The nano-silica sol was pretreated by activation with 0.1 mol / L hydrochloric acid solution for 30 min. The preferred conditions for the composite chelation reaction included a temperature of 40℃, a pH of 3.5, and a reaction time of 10 min. The composite chelation reaction was carried out under stirring at a speed of 90 rpm.

[0102] The system obtained from the composite chelation reaction was mixed with reagents and subjected to pulsed microbubble flotation. The reagents consisted of a copper scavenger and a frother. The copper scavenger was sodium isopropyl xanthate, with a dosage of 30 g / t. The frother was methyl isobutyl methanol, with a dosage of 15 g / t. The reagents were added in two batches, half before flotation and the other half during the middle of flotation. The pulsed microbubble flotation conditions were as follows: a self-priming microbubble flotation machine was used, with a pulse pressure of 0.3 MPa, a pulse frequency of 5 Hz, a bubble size of 65 μm, a microbubble ratio of 75%, and a flotation time of 6 min.

[0103] The obtained copper concentrate and aluminum concentrate are dehydrated and dried separately. The copper concentrate is dehydrated and dried by high-frequency eddy current dehydration, and the aluminum concentrate is dehydrated and dried by low-temperature vacuum drying.

[0104] The obtained high-purity copper powder contains 99.52% copper and 0.28% aluminum; the high-purity aluminum powder contains 99.05% aluminum and 0.18% copper.

[0105] The test results show that the final product obtained after the above process has excellent performance indicators.

[0106] Copper powder products: The total yield is 12.5%. Among them, the large-particle copper powder obtained by three-stage dry sorting has a purity of 99.6%, and the small-particle copper powder obtained by wet co-processing has a purity of 99.52%. The final mixed copper powder product has a weighted purity of up to 99.55%, and the aluminum impurity content is strictly controlled below 0.28%.

[0107] Aluminum powder products: Total yield was 15.3%. Large-particle aluminum powder had a purity of 99.1%, and small-particle aluminum powder had a purity of 99.05%. The final mixed aluminum powder product had a weighted purity of 99.07%, with copper impurities as low as 0.18%.

[0108] Black powder product: The yield is as high as 65.8%, with an active substance content of 96.5% and a total copper and aluminum metal impurities of only 0.35%, providing an excellent raw material for subsequent hydrometallurgy and significantly reducing the difficulty and cost of subsequent purification.

[0109] Environmental indicators: The wastewater generated by the core wet co-process unit of this process has a chemical oxygen demand (COD) of less than 85 mg / L. It can be reused or discharged in compliance with standards with only simple treatment. Compared with the traditional all-wet process (COD>5000 mg / L), the wastewater treatment load and cost are reduced by more than 90%.

[0110] Example 2

[0111] Taking ternary lithium batteries as an example, waste ternary batteries are pre-discharged, disassembled, coarsely crushed and finely crushed in sequence to obtain crushed material; the crushed material includes black powder (positive and negative electrode active materials), copper foil fragments, aluminum foil fragments, separator fragments and plastic fragments; the particle size is 0.1mm~5mm;

[0112] 2 kg of crushed material was subjected to primary dry separation to obtain light and heavy components. The conditions for primary dry separation were as follows: an air classifier was used, the wind speed was 6.5 m / s, and the angle between the feed inlet and the horizontal plane was 20° (i.e., the airflow angle). The air classifier included an upper light component outlet and a lower heavy component collection area. The upper light component outlet was equipped with a vortex stabilizing plate with an opening ratio of 40%. The lower heavy component collection area was equipped with stepped baffles, which consisted of three levels with a height difference of 30 mm between each level.

[0113] The obtained heavy components were subjected to two-stage dry separation to obtain black-rich powder and copper-aluminum-rich mixture. The conditions and parameters of the two-stage dry separation were as follows: eddy current separator was used, rotor speed was 3000 rpm (corresponding to magnetic field frequency of 50 Hz); magnetic pole arrangement was alternating N-S poles, number of poles was 8, pole arc coefficient was 0.75; belt speed was 2.0 m / s; material layer thickness was 5 mm; the residual copper and aluminum content in the black-rich powder was 2.9%, and the copper and aluminum content in the copper-aluminum-rich mixture was 97.2%.

[0114] The obtained black powder was finely classified to obtain fine powder containing metal and black powder. The fine classification was carried out using an air classifier with the following parameters: classifier speed of 3000 rpm, air pressure of 0.5 MPa, and cutting particle size D50 of 0.3 mm.

[0115] The obtained copper-aluminum mixture was subjected to particle size classification using a vibrating screen to obtain coarse copper-aluminum particles and fine copper-aluminum particles; the particle size of the coarse copper-aluminum particles was ≥0.8mm; the particle size of the fine copper-aluminum particles was <0.8mm.

[0116] The obtained coarse copper and aluminum particles were subjected to a three-stage dry separation process to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder. The conditions for the three-stage dry separation were as follows: a high-voltage electrostatic separator was used with a voltage of 40kV, a drum speed of 100rpm, a distance of 70mm between the corona electrode and the drum, a distance of 135mm between the electrostatic electrode and the drum, and an ambient relative humidity of 40%. The obtained large-particle high-purity copper powder contained 99.55% copper and 0.30% aluminum; the large-particle high-purity aluminum powder contained 99.28% aluminum and 0.16% copper.

[0117] The obtained fine copper and aluminum particles were subjected to electrochemical pretreatment, composite chelation reaction and pulse microbubble flotation in sequence to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively.

[0118] The electrochemical pretreatment process includes: mixing the fine-grained copper-aluminum particles with an electrolyte, followed by electrochemical treatment; the electrolyte is a citric acid solution with a mass concentration of 0.5%; the solid-liquid ratio of the resulting mixture is 1:8; the electrochemical treatment parameters are: the anode is a titanium-based ruthenium-iridium coated electrode (size 200). The cathode is a stainless steel cathode (300mm); a DC pulse power supply is used with a voltage of 1.2V, a frequency of 30Hz, a duty cycle of 50%, and a processing time of 4min. The electrochemical pretreatment is carried out under stirring conditions, and the stirring speed is 120rpm.

[0119] The electrochemically pretreated system was mixed with a chelating agent to carry out a composite chelation reaction. The chelating agent included 1.0% citric acid, 0.15% mercaptobenzotriazole, 0.3% nano-silica sol, 0.05% sodium polyaspartate, and the balance being water. The nano-silica sol was pretreated by activation with 0.1 mol / L hydrochloric acid solution for 30 min. The preferred conditions for the composite chelation reaction included a temperature of 40℃, a pH of 3.5, and a reaction time of 10 min. The composite chelation reaction was carried out under stirring at a speed of 90 rpm.

[0120] The system obtained from the composite chelation reaction was mixed with reagents and subjected to pulsed microbubble flotation. The reagents consisted of a copper scavenger and a frother. The copper scavenger was sodium isopropyl xanthate, with a dosage of 30 g / t. The frother was methyl isobutyl methanol, with a dosage of 15 g / t. The reagents were added in two batches, half before flotation and the other half during the middle of flotation. The pulsed microbubble flotation conditions were as follows: a self-priming microbubble flotation machine was used, with a pulse pressure of 0.3 MPa, a pulse frequency of 5 Hz, a bubble size of 65 μm, a microbubble ratio of 75%, and a flotation time of 7 min.

[0121] The obtained copper concentrate and aluminum concentrate are dehydrated and dried separately. The copper concentrate is dehydrated and dried by high-frequency eddy current dehydration, and the aluminum concentrate is dehydrated and dried by low-temperature vacuum drying.

[0122] The obtained high-purity copper powder with small particles has a copper content of 99.48% and an aluminum content of 0.31%; the high-purity aluminum powder with small particles has an aluminum content of 98.95% and a copper content of 0.22%.

[0123] The test results show that this process also exhibits excellent sorting performance for waste ternary lithium batteries with more complex compositions.

[0124] Copper powder product: total yield was 13.8%. The final mixed copper powder product had a weighted purity of 99.52% (Al: 0.28%). Aluminum powder product: total yield was 16.2%, and the final mixed aluminum powder product had a weighted purity of 99.15% (Cu: 0.18%). This demonstrates the universality and efficient separation capability of the electrochemical-chelation synergistic mechanism in this scheme for copper and aluminum foil in different types of batteries.

[0125] Black powder product: yield 62.5%, active substance content 95.8%, total copper and aluminum impurities 0.42%. High-grade black powder lays a solid foundation for the efficient recovery of valuable metals;

[0126] Valuable metal recovery rate: The recovery rate of valuable metals in the black powder was measured to be 96.5%, 97.2%, 96.8%, and 97.1%, respectively.

[0127] Environmental and cost advantages: The low chemical consumption, low water consumption and extremely low wastewater pollution load of the wet process unit can reduce the overall operating cost by more than 30% compared with the traditional process.

[0128] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for sorting waste battery shredded material, characterized in that, Includes the following steps: The waste battery shreds are subjected to primary dry sorting to obtain light components and heavy components; the heavy components include copper, aluminum and black powder. The heavy components are subjected to two-stage dry separation to obtain black-rich powder and copper-aluminum-rich mixture. The copper-aluminum mixture is subjected to particle size classification to obtain coarse copper-aluminum and fine copper-aluminum; the particle size of the coarse copper-aluminum is ≥0.8mm; the particle size of the fine copper-aluminum is <0.8mm. The coarse copper and aluminum particles are subjected to a three-stage dry separation process to obtain large-particle high-purity copper powder and large-particle high-purity aluminum powder. The conditions and parameters for the three-stage dry separation process include: using a high-voltage electrostatic separator with a voltage of 35~50kV, a drum speed of 80~120rpm, a distance of 60~80mm between the corona electrode and the drum, a distance of 120~150mm between the electrostatic electrode and the drum, and an ambient relative humidity of <45%. The large-particle high-purity copper powder has a copper content ≥99.5% and an aluminum content ≤0.3%; the large-particle high-purity aluminum powder has an aluminum content ≥99.0% and a copper content ≤0.2%. The fine copper and aluminum particles were subjected to electrochemical pretreatment, composite chelation reaction and pulsed microbubble flotation in sequence to obtain small-particle high-purity copper powder and small-particle high-purity aluminum powder, respectively. The copper content of the small-particle high-purity copper powder was ≥99.3% and the aluminum content was ≤0.35%. The aluminum content of the small-particle high-purity aluminum powder was ≥98.5% and the copper content was ≤0.25%.

2. The sorting method according to claim 1, characterized in that, The conditions and parameters for the primary dry separation include: using an airflow separator, an air velocity of 5~8m / s, and an angle of 15~25° between the feed inlet and the horizontal plane.

3. The sorting method according to claim 1, characterized in that, The conditions and parameters for the two-stage dry separation include: using an eddy current separator with a rotor speed of 2800~3200 rpm; the magnetic pole arrangement is alternating N and N poles with a pole number of 8 and a pole arc coefficient of 0.75; the belt speed is 1.8~2.2 m / s; and the material layer thickness is 3~8 mm.

4. The sorting method according to claim 1, characterized in that, After obtaining the black-rich powder, the process further includes fine grading of the black-rich powder to obtain fine powder containing metal and black powder. The fine classification is performed using an air classifier or a vibrating screen. The parameters for using an air classifier include: classifier speed of 2500~3500 rpm, inlet pressure of 0.4~0.6 MPa, and cutting particle size D50 of 0.25~0.35 mm; The parameters for using a vibrating screen include: vibration frequency of 25~35Hz, amplitude of 2~4mm, and screen mesh size of 400 mesh for the upper layer and 200 mesh for the lower layer.

5. The sorting method according to claim 1, characterized in that, The electrochemical pretreatment process includes: mixing the fine copper-aluminum particles with the electrolyte and then performing electrochemical treatment; The electrolyte is a citric acid solution with a mass concentration of 0.5%; the solid-liquid ratio of the mixed solution is 1:

8. The electrochemical treatment conditions include: the anode is a titanium-based ruthenium-iridium coated electrode, and the cathode is a stainless steel cathode; a DC pulse power supply is used with a voltage of 0.8~1.2V, a frequency of 20~50Hz, a duty cycle of 40~60%, and a treatment time of 3~5min; the electrochemical pretreatment is carried out under stirring conditions, and the stirring speed is 120rpm.

6. The sorting method according to claim 1, characterized in that, The process of the composite chelation reaction includes: mixing the electrochemically pretreated system with the chelating agent solution to carry out the composite chelation reaction; The chelating agent solution comprises the following components in weight percentage: 0.5-1.5% organic acid, 0.05-0.2% mercaptobenzotriazole, 0.1-0.5% nano-silica sol, 0.01-0.1% sodium polyaspartate, and the balance being water; The conditions for the composite chelation reaction include: a temperature of 35~45℃, a pH value of 3.0~4.0, a reaction time of 8~12min, and the composite chelation reaction is carried out under stirring conditions with a stirring speed of 80~100rpm.

7. The sorting method according to claim 1, characterized in that, The pulsed microbubble flotation process includes: mixing the system obtained from the composite chelation reaction with the reagent, and then performing pulsed microbubble flotation. The agent includes a copper scavenger and a foaming agent; the copper scavenger is sodium isopropyl xanthate, and the dosage of the copper scavenger is 20~40 g / t; the foaming agent is methyl isobutyl methanol, and the dosage of the foaming agent is 10~20 g / t. The reagent is added in two stages, with half added before flotation and the other half added during the middle of flotation. The conditions and parameters for pulsed microbubble flotation include: using a self-priming microbubble flotation machine, a pulse pressure of 0.2~0.4MPa, a pulse frequency of 3~8Hz, a bubble size of 30~100μm, a microbubble ratio of >70%, and a flotation time of 5~8min.

Images