Method for recycling valuable metals from batteries in a full-chain integrated manner and roasting device
By improving the structure and process of the roasting equipment, using strong magnets and ultrasonic generators to separate nickel and cobalt, and combining water leaching and acid leaching processes, the problem of low lithium resource recovery rate was solved, achieving efficient and environmentally friendly lithium resource recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG BRUNP RECYCLING TECH CO LTD
- Filing Date
- 2023-03-15
- Publication Date
- 2026-08-04
AI Technical Summary
In the current lithium resource recycling process, it is difficult to further improve the lithium recovery rate. Furthermore, the wet leaching method has the problems of high reagent consumption, long process flow and environmental pollution risk, and it is difficult to deeply separate lithium from other metals.
An improved roasting device is used, with multiple heating sections and magnetic attraction sections. A strong magnet and an ultrasonic generator are used to attach nickel and cobalt to the magnetic attraction section. Nickel and cobalt are separated by magnetic attraction and ultrasonic oscillation. Combined with reduction roasting and water leaching and acid leaching processes, lithium, nickel, cobalt and manganese elements are separated.
It improves lithium recovery rate, reduces nickel-cobalt encapsulation during reduction roasting, simplifies separation process, reduces environmental pollution risk, and improves lithium recovery efficiency.
Smart Images
Figure CN116802887B_ABST
Abstract
Description
Technical Field
[0001] This disclosure pertains to the field of lithium battery technology, and more specifically, relates to a method and calcination apparatus for the integrated, whole-chain, targeted recycling of valuable metals from batteries. Background Technology
[0002] Against the backdrop of the rapid development of new energy vehicles, lithium-ion batteries are widely used due to their significant advantages such as high voltage, large specific capacity, long lifespan, and no memory effect. Lithium metal, as an indispensable component of lithium-ion batteries, has received much attention. Currently, lithium resources are in short supply, and prices are soaring, making lithium resource development an urgent priority. Besides extracting lithium resources from salt lakes or lithium mines, spent lithium batteries are also a "lithium mine." The lithium content in spent lithium batteries can be as high as 5% to 7%, far exceeding that of lithium found in nature. With the rapid development of new energy vehicles, the demand for lithium is increasing year by year. Recycling lithium from spent batteries and achieving targeted recycling of lithium resources, returning them to the battery industry, and building "integrated industrial parks across the entire supply chain" have become the primary choice for most lithium battery cathode material manufacturers to reduce costs and increase efficiency.
[0003] Currently, wet leaching is the most common method for lithium resource recovery, generally employing processes such as acid leaching, separation and purification, and extraction. However, this method consumes a large amount of reagents, has a long process flow, and is prone to environmental pollution. Furthermore, acid leaching has weak selectivity, as other metals in the cathode material, such as nickel, cobalt, and manganese, leach out simultaneously with lithium, making deep separation difficult. Chinese patent CN112374511A describes acid leaching of waste lithium-ion battery cathode materials followed by multi-stage extraction to obtain a lithium-containing extract and a nickel-cobalt-manganese back-extraction solution. During the extraction process, lithium inevitably enters the back-extraction phase, reducing the lithium recovery rate. Some researchers have optimized the pretreatment steps by reducing and roasting the waste cathode material to achieve front-end lithium extraction, reducing lithium loss and achieving a lithium recovery rate exceeding 90%. However, the lithium recovery rate based on the reduction and roasting process is difficult to further improve.
[0004] In view of this, this disclosure is hereby made. Summary of the Invention
[0005] The purpose of this disclosure is to provide a method and calcination apparatus for the integrated, whole-chain, battery-oriented recycling of valuable metals, with the aim of further improving lithium recovery rate.
[0006] To achieve the above-mentioned objectives of this disclosure, the following technical solutions may be adopted:
[0007] The solution provided in this disclosure includes a method for the whole-chain integrated targeted recycling of valuable metals from batteries, comprising the following steps: reducing and roasting a mixture of waste lithium battery cathode material and reducing agent;
[0008] The reduction roasting process is carried out in a furnace with multiple heating sections. A magnetic suction section is set between two adjacent heating sections, and nickel and cobalt are attached to the magnetic suction section during the roasting process.
[0009] In some embodiments of this disclosure, each magnetic attraction segment is provided with a strong magnet and an ultrasonic generator, so as to use the ultrasonic generator to perform ultrasonic oscillation and use the strong magnet to generate a magnetic attraction effect on nickel and cobalt.
[0010] The magnetic flux of the strong magnet is 8000Gs-15000Gs.
[0011] In some embodiments of this disclosure, the ultrasonic generator is turned on intermittently, with each turn lasting 15-30 minutes and an interval of 20-40 minutes, and the ultrasonic frequency is 25 kHz-50 kHz.
[0012] In some embodiments of this disclosure, the furnace body is tilted so that the material to be roasted passes through each heating section and magnetic suction section in sequence during the roasting process. A partition switch is provided between each heating section and the magnetic suction section adjacent to the conveying direction.
[0013] In some embodiments of this disclosure, the length ratio of each magnetic suction section to the heating section is 0.2-0.5:1, and the material stays in each heating section for 30-60 minutes.
[0014] In some embodiments of this disclosure, the furnace body is a rotary kiln.
[0015] In some embodiments of this disclosure, the heating section and the magnetic attraction section form an angle of 1°-10° with the horizontal plane.
[0016] In some embodiments of this disclosure, there are 2 to 5 heating sections, and a magnetic suction section is also provided between the heating section near the discharge end of the furnace body and the discharge port.
[0017] In some embodiments of this disclosure, during the reduction calcination process, the calcination temperature is controlled at 500℃-700℃ and the calcination time is 3h-8h.
[0018] In some embodiments of this disclosure, the calcination atmosphere is a non-oxidizing atmosphere.
[0019] In some embodiments of this disclosure, the non-oxidizing atmosphere is selected from at least one of nitrogen, argon, and hydrogen.
[0020] In some embodiments of this disclosure, the flow rate of the non-oxidizing atmosphere is 10 mL / min to 200 mL / min.
[0021] In some embodiments of this disclosure, the mass ratio of waste lithium battery cathode material to reducing agent is 3-4:1.
[0022] In some embodiments of this disclosure, the mixture of waste lithium battery cathode material and reducing agent is a mixed powder.
[0023] In some embodiments of this disclosure, waste lithium battery cathode material and reducing agent are ball-milled to obtain a mixed powder.
[0024] In some embodiments of this disclosure, the ball milling time is controlled to be 30 min to 150 min, and the ball-to-material ratio is 1 to 50:1.
[0025] In some embodiments of this disclosure, the reducing agent is inorganic carbon.
[0026] In some embodiments of this disclosure, the inorganic carbon is selected from at least one of bamboo charcoal, straw charcoal, wood charcoal, graphite, and carbon black.
[0027] In some embodiments of this disclosure, the method further includes: leaching the solid product obtained after reduction roasting with water to obtain a lithium-rich solution and a water-leached residue.
[0028] In some embodiments of this disclosure, the water leaching process includes: mixing the solid product obtained after reduction roasting with water, reacting it with carbon dioxide, and then performing solid-liquid separation to obtain a lithium-rich solution and water-leached residue.
[0029] In some embodiments of this disclosure, the carbon dioxide introduction time is 30 min to 120 min.
[0030] In some embodiments of this disclosure, 1g of solid product corresponds to a water volume of 5mL-20mL and a carbon dioxide flow rate of 100mL / min-1000mL / min.
[0031] In some embodiments of this disclosure, the method further includes: collecting the magnetic powder adhering to the magnetic section during the reduction roasting process, mixing the magnetic powder and water leaching residue, and then acid leaching with inorganic acid and oxidant to obtain a nickel-cobalt-manganese solution.
[0032] In some embodiments of this disclosure, the solid-liquid ratio is controlled to be 1:3-10 during acid leaching, and the leaching time is 1h-10h.
[0033] In some embodiments of this disclosure, the oxidant is selected from at least one of air, oxygen, and hydrogen peroxide.
[0034] In some embodiments of this disclosure, the oxidant is an aqueous solution of hydrogen peroxide, the mass ratio of the aqueous solution of hydrogen peroxide to the acid leaching residue is controlled to be 10-15:100, and the mass fraction of the aqueous solution of hydrogen peroxide is 20%-50%.
[0035] In some embodiments of this disclosure, the inorganic acid is selected from at least one of H2SO4, HCl and HNO3.
[0036] In some embodiments of this disclosure, the concentration of inorganic acid in the leaching solution is 0.5 mol / L-4 mol / L, and the molar ratio of the amount of inorganic acid to the total amount of nickel, cobalt, and manganese is 1-1.1:1.
[0037] The solution provided in this disclosure also includes a roasting apparatus, including a furnace body having multiple heating sections, with a magnetic adsorption section provided between each pair of adjacent heating sections, so that nickel and cobalt can be attached to the magnetic adsorption section during the roasting process.
[0038] In some embodiments of this disclosure, each magnetic attraction segment is provided with a strong magnet and an ultrasonic generator, so as to use the ultrasonic generator to perform ultrasonic oscillation and use the strong magnet to generate a magnetic attraction effect on nickel and cobalt; wherein, the magnetic flux of the strong magnet is 8000Gs-15000Gs.
[0039] In some embodiments of this disclosure, the furnace body is tilted so that the material to be roasted passes through each heating section and magnetic suction section in sequence, and a partition switch is provided between each heating section and the magnetic suction section adjacent to the conveying direction.
[0040] In some embodiments of this disclosure, the length ratio of each magnetic attraction segment to the heating segment is 0.2-0.5:1.
[0041] In some embodiments of this disclosure, the furnace body is a rotary kiln.
[0042] In some embodiments of this disclosure, the heating section and the magnetic attraction section form an angle of 1°-10° with the horizontal plane.
[0043] In some embodiments of this disclosure, there are 2 to 5 heating sections, and a magnetic suction section is also provided between the heating section near the discharge end of the furnace body and the discharge port.
[0044] By improving the structure of the roasting equipment, multiple heating sections are formed, and magnetic suction sections are set between adjacent heating sections. When the waste lithium battery cathode material and reducing agent are reduced and roasted in the improved roasting equipment, the nickel and cobalt can be attached to the magnetic suction section under the magnetic attraction. This allows the nickel and cobalt wrapped on the surface of the waste cathode material to fall off, thereby exposing the cathode material more fully, improving the efficiency of reduction roasting, and enabling the lithium element to be completely replaced, thus improving the lithium recovery rate. Attached Figure Description
[0045] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0046] Figure 1 A process flow diagram of the separation method is provided for embodiments of this disclosure;
[0047] Figure 2 This is a schematic diagram of the structure of the calcination equipment provided in the embodiments of this disclosure;
[0048] Figure 3 for Figure 2 Cross-sectional view of the calcining equipment.
[0049] Icons: 100-Reduction roasting equipment; 110-Feed inlet; 120-Discharge outlet; 130-Heating section; 131-Baffle switch; 140-Magnetic suction section; 141-Strong magnet; 142-Ultrasonic generator; 150-Base. Detailed Implementation
[0050] The embodiments of this disclosure will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this disclosure. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0051] The endpoints and any values of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values should be understood to include values close to such ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein.
[0052] This disclosure provides a method for the integrated, end-to-end, targeted recycling of valuable metals from batteries. Please refer to [link / reference]. Figure 1 It includes the following steps:
[0053] S1, Mixing
[0054] Mix the waste lithium battery cathode material and reducing agent evenly and set aside.
[0055] In some embodiments, the mass ratio of waste lithium battery cathode material to reducing agent is 3-4:1, such as 3.0:1, 3.5:1, 4.0:1, etc. By further controlling the amount of reducing agent, the reaction can be made to proceed fully.
[0056] In some embodiments, the reducing agent can be inorganic carbon. Any carbon material with reducing properties is suitable for the embodiments of this disclosure and can be commercially available bamboo charcoal, straw charcoal, wood charcoal, graphite and carbon black, etc., but is not limited thereto.
[0057] In some embodiments, waste lithium battery cathode material and reducing agent can be uniformly mixed to obtain a mixed powder by ball milling. The ball milling time is controlled to be 30 min-150 min, and the ball-to-material ratio is 1-50:1. Specifically, the ball milling time can be 30 min, 50 min, 70 min, 90 min, 110 min, 130 min, 150 min, etc.; the ball-to-material ratio can be 1:1, 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, etc.
[0058] S2, Reduction roasting
[0059] The mixed powder obtained in S1 was subjected to reduction calcination. The inventor improved the reduction calcination equipment. Please refer to... Figure 2 and Figure 3 The reduction roasting equipment 100 includes a base 150 and a main structure mounted on the base 150. The main structure includes a feed inlet 110, a discharge outlet 120, multiple heating sections 130, and multiple magnetic suction sections 140.
[0060] Specifically, the main structure is a furnace body with multiple heating sections 130. A magnetic suction section 140 is provided between two adjacent heating sections 130. The material is attached to the magnetic suction section 140 by magnetic attraction.
[0061] It should be noted that in existing technologies, elemental nickel and cobalt are generated during the reduction roasting process of waste cathode materials. These elements coat the surface of the waste cathode materials, inhibiting further reduction reactions and preventing further improvement in lithium recovery rates. By improving the reduction roasting equipment 100, the ultrasonic and magnetic attraction of the magnetic attraction section 140 can remove the nickel and cobalt coating from the surface of the waste cathode materials, allowing for more complete exposure of the cathode materials, improving the efficiency of reduction roasting, and enabling complete replacement of lithium.
[0062] Furthermore, each of the magnetic attraction sections 140 is equipped with a strong magnet 141 and an ultrasonic generator 142. The magnetic flux of the strong magnet 141 is 8000Gs-15000Gs. The strong magnet 141 and the ultrasonic generator 142 can be installed at the same position in the conveying direction, corresponding to each other. The ultrasonic oscillation makes the material easier to separate, and the magnetic attraction generated by the strong magnet 141 causes nickel and cobalt to adhere to the magnetic attraction section 140. The strong magnet 141 has a large magnetic flux to better attract nickel and cobalt. The magnetic flux can be 8000Gs, 9000Gs, 10000Gs, 11000Gs, 12000Gs, 13000Gs, 14000Gs, 15000Gs, etc.
[0063] In some embodiments, the ultrasonic generator 142 is intermittently activated, with each activation lasting 15-30 minutes and an interval of 20-40 minutes, at an ultrasonic frequency of 25 kHz-50 kHz. That is, throughout the calcination process, the ultrasonic generator 142 operates intermittently, once every 20-40 minutes, with each activation lasting 15-30 minutes, and this cycle repeats. Intermittent ultrasonic treatment effectively prevents nickel-cobalt elements from coating the surface of the waste cathode material, and is more energy-efficient than prolonged ultrasonic operation.
[0064] Specifically, the ultrasonic generator 142 can be turned on for 15 minutes, 18 minutes, 20 minutes, 25 minutes, 30 minutes, etc., with intervals of 20 minutes, 30 minutes, 40 minutes, etc., and ultrasonic frequencies of 25 kHz, 30 kHz, 40 kHz, 50 kHz, etc.
[0065] Specifically, the magnetic attraction section 140 has a magnetic attraction effect on the nickel-cobalt alloy, enabling the separation of the powder after ultrasonic crushing to obtain solid nickel-cobalt and lithium carbonate. Since lithium carbonate is non-magnetic, it re-enters the next heating section 130 for further reduction and roasting, generating elemental nickel-cobalt which then becomes magnetic and is attracted again in the strong magnetic field section. Repeated processing allows for more thorough separation of nickel-cobalt and lithium elements, improving lithium recovery rate. Using an indirect method to remove elemental nickel-cobalt coated on the surface of the waste cathode material during the reduction process, compared to directly adding a dispersant, avoids introducing impurities and saves on subsequent impurity removal costs.
[0066] In some embodiments, the furnace body is tilted so that the material to be roasted passes sequentially through each heating section 130 and magnetic suction section 140. A baffle switch 131 is provided between each heating section 130 and the magnetic suction section 140 adjacent to it in the conveying direction. After the heating time in the heating section 130 meets the requirements, the baffle switch 131 can be opened to allow the material to enter the next magnetic suction section 140. The residence time of the material in each heating section can be controlled to be 30-60 minutes (e.g., 30 minutes, 40 minutes, 50 minutes, 60 minutes, etc.). There can be 2-5 heating sections 130. A magnetic suction section 140 is also provided between the heating section 130 near the discharge end of the furnace body and the discharge port 120, so that the material is finally discharged after another ultrasonic crushing and magnetic separation, further ensuring the complete removal of nickel and cobalt.
[0067] Specifically, the partition switch 131 can be a general partition that can block the heating section 130 and the magnetic section 140, and can be manually controlled; or it can be electrically controlled to mechanically realize the raising and lowering of the partition switch 131.
[0068] In some embodiments, the furnace body is a rotary kiln structure with an inclination angle of 1°-10°. The length ratio of each magnetic suction section 140 to the heating section 130 is 0.2-0.5:1. The lengths of multiple heating sections 130 can be approximately the same, and the lengths of each magnetic suction section 140 can also be approximately the same, with the length of the magnetic suction section 140 being less than the length of the heating section 130. The term "length" refers to the distance that the section extends along the conveying direction.
[0069] Specifically, the tilt angle α of the rotary kiln can be 1°, 3°, 5°, 7°, 10°, etc., and the length ratio of the magnetic suction section 140 to the heating section 130 can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, etc.
[0070] Furthermore, during the reduction roasting process, the roasting temperature is controlled at 500℃-700℃, the roasting time is 3h-8h, and the roasting atmosphere is a non-oxidizing atmosphere. By controlling the roasting temperature and time, lithium is fully replaced. Specifically, the roasting temperature can be 500℃, 550℃, 600℃, 650℃, 700℃, etc., and the roasting time can be 3h, 4h, 5h, 6h, 7h, 8h, etc.
[0071] In some embodiments, the non-oxidizing atmosphere is selected from at least one of nitrogen, argon, and hydrogen, and can be any one or more of them. The flow rate of the non-oxidizing atmosphere can be 10 mL / min to 200 mL / min, such as 10 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, etc.
[0072] S3, water immersion
[0073] The solid product (final product) obtained after reduction roasting is leached with water to obtain a lithium-rich solution and a water-leached residue. The water leaching process dissolves the lithium in the solid product. In actual operation, the solid product obtained after reduction roasting is mixed with water, and carbon dioxide is introduced for reaction for 30-120 minutes. Afterward, solid-liquid separation is performed to obtain the lithium-rich solution and the water-leached residue. Lithium carbonate is not easily soluble in water, while the generated lithium bicarbonate is easily soluble in water, thus dissolving the lithium in the system.
[0074] Specifically, the carbon dioxide introduction time, i.e., the reaction time, can be 30 min, 50 min, 80 min, 100 min, 120 min, etc. The solid-liquid separation method after the reaction is complete is not limited, and can include, but is not limited to, filtration.
[0075] In some embodiments, 1g of solid product corresponds to 5mL-20mL of water and a carbon dioxide flow rate of 100mL / min-1000mL / min, thereby controlling the amount of raw material to better promote lithium dissolution. Specifically, 1g of solid product can correspond to 5mL, 10mL, 15mL, 20mL, etc., and the carbon dioxide flow rate can be 100mL / min, 300mL / min, 500mL / min, 700mL / min, 1000mL / min, etc.
[0076] S4, acid leaching
[0077] The magnetic powder adhering to the magnetic section 140 during the reduction roasting process is collected. The magnetic powder and water leaching residue are mixed and acid leached with inorganic acid and oxidant to obtain a nickel-cobalt-manganese solution for further recovery of nickel, cobalt and manganese elements.
[0078] In some embodiments, the solid-liquid ratio is controlled at 1:3-10 during acid leaching, and the leaching time is 1h-10h to ensure that nickel, cobalt, and manganese are fully dissolved and leached. Specifically, the solid-liquid ratio refers to the ratio of the amount of solid material to the amount of acid leaching solution, which can be 1:3, 1:5, 1:8, 1:10, etc.; the leaching time can be 1h, 3h, 5h, 8h, 10h, etc.
[0079] In some embodiments, the inorganic acid is selected from at least one of H2SO4, HCl, and HNO3, and may be any one or more of the above. The concentration of the inorganic acid in the leaching solution is 0.5 mol / L-4 mol / L, and the molar ratio of the amount of inorganic acid to the total amount of nickel, cobalt, and manganese is 1-1.1:1, so that nickel, cobalt, and manganese can be fully leached.
[0080] Specifically, the concentration of inorganic acid in the acid leaching solution can be 0.5 mol / L, 1.0 mol / L, 2.0 mol / L, 3.0 mol / L, 4.0 mol / L, etc., and the molar ratio of the amount of inorganic acid to the total amount of nickel, cobalt and manganese elements can be 1.00:1, 1.05:1, 1.10:1, etc., with a slight excess of inorganic acid being preferable.
[0081] In some embodiments, the oxidant is selected from at least one of air, oxygen, and hydrogen peroxide, and may be one or more, with hydrogen peroxide generally preferred. The raw material may be an aqueous solution of hydrogen peroxide, and the mass ratio of the aqueous solution of hydrogen peroxide to the acid leaching residue is controlled to be 10-15:100 (e.g., 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, etc.), and the mass fraction of the aqueous solution of hydrogen peroxide is 20%-50%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.
[0082] This disclosure also provides a roasting apparatus, referring to Figure 2 and Figure 3 The furnace includes a furnace body with multiple heating sections 130. A magnetic attraction section 140 is provided between each pair of adjacent heating sections 130 so that nickel and cobalt can adhere to the magnetic attraction section 140 during the roasting process. Through the improvement of the furnace body structure, the nickel and cobalt can adhere to the magnetic attraction section 140 under the magnetic attraction, which can make the nickel and cobalt wrapped on the surface of the waste cathode material fall off, thereby making the cathode material more fully exposed and improving the efficiency of reduction roasting.
[0083] It should be noted that the specific structure of the roasting apparatus will not be described again; please refer to other parts of the instruction manual.
[0084] The features and performance of this disclosure will be further described in detail below with reference to embodiments.
[0085] It should be noted that the composition of the waste NCM523 cathode material processed in the following embodiments and comparative examples is shown in Table 1.
[0086] Table 1. Composition of waste NCM523 cathode material
[0087] wt% 6.15 10.26 14.57 13.29 0.08
[0088] Example 1
[0089] This embodiment provides a method for the integrated, end-to-end, targeted recycling of valuable metals from batteries, including the following steps:
[0090] (1) Mix 35g of waste NCM523 cathode material with 10g of bamboo charcoal and then mechanically ball mill for 1 hour. The ball-to-material ratio is 10:1.
[0091] (2) The mixture obtained in S1 was calcined at 600°C for 4 hours in a nitrogen atmosphere at a flow rate of 100 mL / min. The structure of the calcination equipment is as follows: Figure 2 and Figure 3 The magnetic flux of the strong magnet was 10000 Gs, the ultrasonic generator had an intermittent interval of 30 min and an on-time of 20 min, the ultrasonic frequency was 30 kHz, the rotary kiln tilt angle α = 2°, the length ratio of each magnetic attraction section to the heating section was 0.3:1, the length of each heating section was 6 m, and the length of each magnetic attraction section was 1.8 m. At this tilt angle, the residence time in each magnetic attraction section was approximately 30 min, and the residence time in each heating section was controlled to be 50 min. There were three heating sections and three magnetic attraction sections, and the total calcination time was 4 h. After the reaction was completed, the powder from the strong magnetic end was collected.
[0092] (3) The solid product obtained in S2 was mixed with water, and carbon dioxide was continuously introduced into it for 120 min. The solid-liquid ratio was 10 mL / g, and the carbon dioxide flow rate was 500 mL / min. After the reaction was completed, the resulting slurry was filtered to obtain a lithium-rich solution and a water-leached residue.
[0093] (4) The water-leached residue and the powder from the strong magnetic end were leached with an inorganic acid and an oxidizing agent to obtain a nickel-cobalt-manganese solution. The inorganic acid was H2SO4 with a concentration of 2 mol / L. The molar ratio of inorganic acid to nickel, cobalt, and manganese was 1.05:1, the solid-liquid ratio was 1:5, the leaching time was 5 hours, and the oxidizing agent was a 30% (w / w) aqueous solution of hydrogen peroxide, which was used at 15% of the mass of the water-leached residue.
[0094] Example 2
[0095] This embodiment provides a method for the integrated, end-to-end, targeted recycling of valuable metals from batteries, including the following steps:
[0096] (1) Mix 30g of waste NCM523 cathode material and 10g of bamboo charcoal and then mechanically ball mill for 30min. The ball-to-material ratio is 1:1.
[0097] (2) The mixture obtained in S1 was calcined at 500°C for 7.5 h in a nitrogen atmosphere at a flow rate of 10 mL / min. The structure of the calcination equipment is as follows: Figure 2 and Figure 3(The difference lies in that it has four heating sections and four magnetic attraction sections.) The magnetic flux of the strong magnet is 8000 Gs, the ultrasonic generator has an intermittent interval of 20 min and an on-time of 15 min, the ultrasonic frequency is 25 kHz, the rotary kiln tilt angle α = 1°, and the length ratio of each magnetic attraction section to the heating section is 0.2:1. The length of each heating section is 6 m, and the length of each magnetic attraction section is 1.2 m. At this tilt angle, the residence time in each magnetic attraction section is approximately 30 min, and the residence time in each heating section is controlled to be 60 min. There are a total of five heating sections and five magnetic attraction sections, with a total calcination time of 7.5 h. After the reaction is complete, the powder from the strong magnetic end is collected.
[0098] (3) The solid product obtained in S2 was mixed with water, and carbon dioxide was continuously introduced into it for 30 min. The solid-liquid ratio was 5 mL / g, and the carbon dioxide flow rate was 1000 mL / min. After the reaction was completed, the resulting slurry was filtered to obtain a lithium-rich solution and a water-leached residue.
[0099] (4) The water-leached residue and the powder from the strong magnetic end were leached with an inorganic acid and an oxidizing agent to obtain a nickel-cobalt-manganese solution. The inorganic acid was H2SO4 with a concentration of 0.5 mol / L. The molar ratio of inorganic acid to nickel, cobalt, and manganese was 1.1:1, the solid-liquid ratio was 1:10, the leaching time was 10 hours, and the oxidizing agent was a 30% aqueous solution of hydrogen peroxide, with the amount of hydrogen peroxide solution being 10% of the mass of the water-leached residue.
[0100] Example 3
[0101] This embodiment provides a method for the integrated, end-to-end, targeted recycling of valuable metals from batteries, including the following steps:
[0102] (1) Mix 40g of waste NCM523 cathode material with 10g of bamboo charcoal and then mechanically ball mill for 150min. The ball-to-material ratio is 50:1.
[0103] (2) The mixture obtained in S1 was calcined at 700°C for 3 hours in a nitrogen atmosphere at a flow rate of 200 mL / min. The structure of the calcination equipment is as follows: Figure 2 and Figure 3 The magnetic flux of the strong magnet was 15000 Gs, the ultrasonic generator had an intermittent interval of 40 min and an on-time of 30 min, the ultrasonic frequency was 50 kHz, the rotary kiln tilt angle α = 10°, and the length ratio of each magnetic attraction section to the heating section was 0.5:1. The heating sections were all 3 m long, and the magnetic attraction sections were all 1.5 m long. At this tilt angle, the residence time in each magnetic attraction section was approximately 10 min, and the residence time in each heating section was controlled to be 50 min. There were three heating sections and three magnetic attraction sections, with a total calcination time of 3 h. After the reaction was complete, the powder from the strong magnetic end was collected.
[0104] (3) The solid product obtained in S2 was mixed with water, and carbon dioxide was continuously introduced into it for 120 min. The solid-liquid ratio was 20 mL / g, and the carbon dioxide flow rate was 100 mL / min. After the reaction was completed, the resulting slurry was filtered to obtain a lithium-rich solution and a water-leached residue.
[0105] (4) The water-leached residue and the powder from the strong magnetic end were leached with an inorganic acid and an oxidizing agent to obtain a nickel-cobalt-manganese solution. The inorganic acid was H2SO4 with a concentration of 4 mol / L. The molar ratio of inorganic acid to nickel, cobalt, and manganese was 1.0:1. The solid-liquid ratio was 1:3. The leaching time was 1 hour. The oxidizing agent was a 30% aqueous solution of hydrogen peroxide, and the amount of hydrogen peroxide solution was 15% of the mass of the water-leached residue.
[0106] Comparative Example 1
[0107] The only difference from Example 1 is that no strong magnet and ultrasonic generator were installed, and conventional rotary kiln equipment was used for reduction roasting.
[0108] Comparative Example 2
[0109] The only difference from Example 1 is that only a strong magnet is installed, and no ultrasonic generator is installed.
[0110] Comparative Example 3
[0111] The only difference from Example 1 is that only an ultrasonic generator is installed, and no strong magnet is installed.
[0112] Comparative Example 4
[0113] The only difference from Example 1 is that the strong magnet is replaced with a weak magnet with a magnetic flux of 800 Gs.
[0114] Comparative Example 5
[0115] The only difference from Example 1 is that the dwell time of each heating section is controlled to be 150 minutes, with a total of five heating sections and five magnetic suction sections, and the total roasting time is 15 hours.
[0116] Test case
[0117] The recovery and leaching rates of lithium in the test examples and comparative examples are shown in Table 2.
[0118] Test method: The lithium leaching rate and recovery rate are calculated based on the element content tested by ICP.
[0119] Table 2. Lithium recovery and leaching rates in the examples and comparative examples.
[0120] Example 1 92.31 96.79 Example 2 92.26 96.73 Example 3 92.23 96.61 Comparative Example 1 83.12 86.58 Comparative Example 2 80.72 93.35 Comparative Example 3 84.65 87.16 Comparative Example 4 85.54 89.08 Comparative Example 5 92.29 96.75
[0121] As shown in Table 2, the lithium recovery and leaching rates in Example 1 were significantly higher than those in the comparative example. In Comparative Example 2, no ultrasonic crushing was performed, resulting in unsatisfactory removal of nickel and cobalt, and insufficient removal of the coated nickel and cobalt. In Comparative Example 3, after generating nickel and cobalt, crushing was performed followed by further roasting; however, this did not remove the nickel and cobalt, and the problem of nickel and cobalt coating remained. In Comparative Example 5, the heating time was extended, and the lithium recovery and leaching rates remained essentially unchanged, but more energy was consumed, which is not conducive to energy conservation and emission reduction.
[0122] The preferred embodiments of this disclosure have been described in detail above; however, this disclosure is not limited thereto. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this disclosure and are all within the protection scope of this disclosure.
[0123] Industrial applicability
[0124] This disclosure involves reducing and roasting waste lithium-ion battery cathode materials with a reducing agent. By improving the structure of the roasting equipment, multiple heating sections are formed, with magnetic adsorption sections between adjacent heating sections. These magnetic adsorption sections allow nickel and cobalt to adhere to the surface of the waste cathode material, causing them to detach and resulting in more complete exposure of the cathode material. This improves the efficiency of the reduction roasting process, ensuring complete displacement of lithium and increasing lithium recovery rate. The improved roasting equipment is simple and easy to implement; the roasting time of each heating section can be controlled manually or electrically, making it convenient for industrial application.
Claims
1. A method for full chain integrated battery directed recycling of valuable metals, characterized by, Includes the following steps: The mixture of waste lithium battery cathode material and reducing agent is reduced and roasted. The reduction roasting process is carried out in a furnace with multiple heating sections, and a magnetic suction section is provided between two adjacent heating sections, so that nickel and cobalt are attached to the magnetic suction section during the roasting process. Each of the magnetic attraction sections is equipped with a strong magnet and an ultrasonic generator, so as to use the ultrasonic generator to perform ultrasonic oscillation and use the strong magnet to generate a magnetic attraction effect on nickel and cobalt; wherein, the magnetic flux of the strong magnet is 8000Gs-15000Gs.
2. The method of claim 1, wherein, The ultrasonic generator is turned on intermittently, with each turn lasting 15-30 minutes and an interval of 20-40 minutes. The ultrasonic frequency is 25 kHz-50 kHz.
3. The method according to any one of claims 1-2, characterized in that, The furnace body is tilted so that the material to be roasted passes through each heating section and magnetic suction section in sequence during the roasting process. Each heating section and the magnetic suction section adjacent to the conveying direction are equipped with a partition switch.
4. The method of claim 3, wherein, The length ratio of the magnetic suction section to the heating section in each segment is 0.2-0.5:1, and the material stays in each heating section for 30-60 minutes.
5. The method of claim 4, wherein, The furnace body is a rotary kiln.
6. The method of claim 5, wherein, The heating section and the magnetic suction section form an angle of 1°-10° with the horizontal plane.
7. The method of claim 4, wherein, The heating section consists of 2 to 5 sections, and a magnetic suction section is also provided between the heating section and the discharge port near the discharge end of the furnace body.
8. The method of claim 1, wherein, During the reduction calcination process, the calcination temperature is controlled at 500℃-700℃ and the calcination time is 3h-8h.
9. The method of claim 8, wherein, The roasting atmosphere is a non-oxidizing atmosphere.
10. The method of claim 9, wherein, The non-oxidizing atmosphere is selected from at least one of nitrogen, argon and hydrogen.
11. The method of claim 10, wherein, The flow rate of the non-oxidizing atmosphere is 10 mL / min to 200 mL / min.
12. The method of claim 1, wherein, The mass ratio of the waste lithium battery cathode material to the reducing agent is 3-4:
1.
13. The method of claim 12, wherein, The mixture of the waste lithium battery cathode material and the reducing agent is a mixed powder.
14. The method of claim 13, wherein, The waste lithium battery cathode material and reducing agent are ball-milled to obtain a mixed powder.
15. The method of claim 14, wherein, The ball milling time should be controlled between 30 and 150 minutes, and the ball-to-material ratio should be 1 to 50:
1.
16. The method of claim 12, wherein, The reducing agent is inorganic carbon.
17. The method of claim 16, wherein, The inorganic carbon is selected from at least one of bamboo charcoal, straw charcoal, wood charcoal, graphite, and carbon black.
18. The method according to claim 1, characterized in that, Also includes: The solid product obtained after reduction roasting is subjected to water leaching to obtain a lithium-rich solution and water-leached residue.
19. The method according to claim 18, characterized in that, The water leaching process includes: mixing the solid product obtained after reduction roasting with water, reacting it with carbon dioxide, and then performing solid-liquid separation to obtain the lithium-rich solution and the water leaching residue.
20. The method according to claim 19, characterized in that, The carbon dioxide introduction time is 30 min-120 min.
21. The method according to claim 19 or 20, characterized in that, 1g of the solid product corresponds to a water volume of 5mL-20mL and a carbon dioxide flow rate of 100mL / min-1000mL / min.
22. The method according to claim 18, characterized in that, Also includes: Collect the magnetic powder adhering to the magnetic section during the reduction roasting process, mix the magnetic powder and the water leaching residue, and perform acid leaching using inorganic acid and oxidant to obtain a nickel-cobalt-manganese solution.
23. The method according to claim 22, characterized in that, The solid-liquid ratio is controlled at 1:3-10 during acid leaching, and the leaching time is 1h-10h.
24. The method according to claim 22, characterized in that, The oxidant is selected from at least one of air, oxygen and hydrogen peroxide.
25. The method according to claim 22, characterized in that, The oxidant is an aqueous solution of hydrogen peroxide, and the mass ratio of the aqueous solution of hydrogen peroxide to the acid leaching residue is controlled at 10-15:100, with the mass fraction of the aqueous solution of hydrogen peroxide being 20%-50%.
26. The method according to claim 22, characterized in that, The inorganic acid is selected from at least one of H2SO4, HCl and HNO3.
27. The method according to claim 26, characterized in that, The concentration of the inorganic acid in the leaching solution is 0.5 mol / L-4 mol / L, and the molar ratio of the amount of inorganic acid to the total amount of nickel, cobalt and manganese is 1-1.1:
1.
28. A calcining apparatus for the method according to any one of claims 1-27, characterized in that, The furnace includes a furnace body having multiple heating sections, with a magnetic suction section provided between each pair of adjacent heating sections to allow nickel and cobalt to adhere to the magnetic suction section during the roasting process. Each of the magnetic attraction sections is equipped with a strong magnet and an ultrasonic generator, so as to use the ultrasonic generator to perform ultrasonic oscillation and use the strong magnet to generate a magnetic attraction effect on nickel and cobalt; wherein, the magnetic flux of the strong magnet is 8000Gs-15000Gs.