Battery black roasting reduction system and its rotary kiln equipment
By installing crushing and limiting components inside the rotary kiln, the problem of calcined material agglomeration was solved, enabling efficient lithium reduction and recovery, and improving production stability and economy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU XINLIYUAN TECHNOLOGY CO LTD
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-09
Smart Images
Figure CN122170640A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery material recycling technology, specifically to a battery black powder roasting and reduction system and its rotary kiln equipment. Background Technology
[0003] The conventional recycling of retired lithium batteries employs a combination of wet and pyrometallurgical processes. The roasting step in the pyrometallurgical process aims to disrupt the crystal structure of lithium nickel cobalt manganese oxide in the lithium black powder, converting lithium into substances such as lithium carbonate, which are easily soluble in acids. This allows for the efficient extraction of lithium from the ternary lithium black powder under a weakly acidic environment.
[0004] However, the rotary kiln and other equipment used in traditional roasting processes can cause the roasted material to clump during the roasting process. The maximum diameter of the clumps can reach 5-15 cm. The clumps contain a large amount of black powder inside the clumps, which prevents them from being fully reduced, thus seriously affecting the lithium recovery rate.
[0005] Therefore, there is a need in the field for a new battery black powder calcination and reduction system and its rotary kiln equipment to solve the above problems. Summary of the Invention
[0006] To address the aforementioned problem—namely, to resolve the issue of calcination material agglomeration in traditional calcination processes leading to insufficient reduction of black powder and thus affecting lithium recovery—the first aspect of this invention provides a rotary kiln device for a battery black powder calcination and reduction system. The rotary kiln device includes a power mechanism and a rotary kiln. The power mechanism is connected to the rotary kiln to drive its rotation. A crushing component is installed within the rotary kiln. This crushing component is configured to be driven to crush the material within the rotary kiln when it rotates. The crushing component is freely placed at the inner bottom of the rotary kiln and moves freely with the rotation of the kiln.
[0007] This setup, incorporating a crushing component within the rotary kiln, continuously pulverizes agglomerated materials. This exposes the black powder trapped within the agglomerates, allowing it to fully contact the reducing agent and high-temperature atmosphere. This ensures the uniformity and thoroughness of the roasting reaction, facilitating the conversion of lithium into acid-soluble substances. Simultaneously, the reduced particle size and increased specific surface area enhance the reduction reaction rate, facilitating subsequent processes. For example, it accelerates the leaching rate in subsequent wet acid leaching, further improving the overall recovery rate of valuable metals (such as lithium, nickel, cobalt, and manganese). Furthermore, continuous material crushing within the rotary kiln ensures the material remains loose, preventing blockages caused by large agglomerates and ensuring smooth material transport, thus enhancing overall operational stability.
[0008] In some embodiments, the crushing component is arranged along the material conveying direction inside the rotary kiln, and the length of the crushing component is less than or equal to the length of the rotary kiln.
[0009] With this setup, the crushing components are arranged along the material conveying direction, ensuring that the material is continuously crushed throughout the reduction process in the rotary kiln, guaranteeing the uniformity of the particle size of the material exiting the kiln and meeting the particle size requirements. The length of the crushing components is set to be less than or equal to the length of the rotary kiln, ensuring that the crushing components are stably placed in the rotary kiln, avoiding kiln balance problems or interference with other components caused by excessively long crushing components, and ensuring the smooth operation of the device.
[0010] In some embodiments, the crushing component includes a plurality of rollers that rotate freely with the rotary kiln.
[0011] With this configuration, multiple rollers increase the crushing contact points and area, improving crushing efficiency. More importantly, multiple rollers work together to carry out the crushing work, distributing the contact stress between the rollers, material, and kiln wall to multiple components and reducing local wear. Arranged freely at the bottom of the rotary kiln, the rollers can rotate as the kiln rotates, eliminating the need for separate drive components. Utilizing the gravity of the rollers and material themselves, the material makes fuller contact with the rollers, enhancing the crushing effect.
[0012] In some embodiments, the roller bar is a hollow roller bar.
[0013] By using hollow rollers in this configuration, the overall mass of the rollers can be effectively reduced while ensuring that the outer diameter and structural strength are sufficient to withstand the crushing pressure. This reduces the load and energy consumption of the power mechanism, allowing multiple rollers to rotate more freely relative to each other to achieve better crushing results. At the same time, it allows for a larger outer diameter of the rollers, increasing the contact area with the material and improving the effect of single-pass crushing, thereby further enhancing crushing efficiency.
[0014] In some embodiments, the surface of the rollers is coated with a tungsten carbide coating.
[0015] With this configuration, the tungsten carbide coating has extremely high hardness and good high temperature and corrosion resistance. The tungsten carbide coating on the surface of the rollers significantly improves wear resistance, reduces the frequency of roller replacement due to wear, lowers maintenance costs, and ensures long-term stable crushing performance.
[0016] In some embodiments, the end faces of the rollers are flat or curved.
[0017] With this configuration, the flat end face forms a surface contact with the two ends of the rotary kiln's interior, ensuring the stability of the roller's position; the curved end face reduces the contact area with the two ends of the rotary kiln's interior, while the curved surface can reduce stress concentration and reduce end face wear.
[0018] In some embodiments, a limiting component is provided at the tail end of the rotary kiln, the limiting component being configured to prevent the rollers from moving out of the rotary kiln and to allow material in the rotary kiln to flow out from its tail end.
[0019] This design ensures that the limiting components keep the rollers within the rotary kiln, preventing them from moving with the material along the kiln's flow path. This guarantees continuous crushing operations and avoids reduced crushing efficiency due to roller misalignment. Simultaneously, it allows for normal material discharge, maintaining process continuity and improving production efficiency. More importantly, by integrating the functions of limiting axial movement of the rollers and allowing the calcined material to pass through, the limiting components simultaneously achieve roller limiting and calcined material screening in the same spatial location. This results in a compact kiln tail structure, eliminating the need for complex external mechanisms for fixing the rollers or screening the calcined material, ensuring smooth discharge of the calcined material and maintaining production continuity.
[0020] In some embodiments, the limiting component includes a plurality of circumferential rings and a plurality of radial rods, each of the circumferential rings having a different diameter, all of the circumferential rings being concentrically arranged and the plurality of circumferential rings being connected by a plurality of radial rods distributed circumferentially, the plurality of circumferential rings and the plurality of radial rods forming a plurality of openings, the maximum opening distance of each of the openings being less than the minimum length of the cross-section of the roller bar.
[0021] This design, combining circumferential rings and radial rods, provides multiple openings for the roasted material, preventing blockages. The multiple circumferential rings themselves act as robust annular reinforcing ribs, while the radial rods distributed circumferentially provide support and connection, linking the rings into a solid whole. This allows the limiting component to withstand the pressure or impact from the rollers and materials, ensuring the stability of the limiting effect. Furthermore, the concentric design of the circumferential rings ensures uniform stress distribution throughout the overall structure, extending the service life of the limiting component.
[0022] In some embodiments, the inner wall of the rotary kiln is provided with an insulation layer.
[0023] By setting up an insulation layer, heat loss can be reduced, roasting energy consumption can be lowered, and energy costs in the production process can be reduced. More importantly, the insulation layer can prevent temperature fluctuations in the kiln, ensure that the roasting reaction is sufficient and uniform, and prevent incomplete roasting reduction caused by temperature changes, thereby further improving lithium conversion efficiency.
[0024] Another aspect of the present invention provides a battery black powder calcination and reduction system, the battery black powder calcination and reduction system including a feeding device, a discharging device, and the above-mentioned rotary kiln device; The feeding device is connected to the beginning of the rotary kiln; The discharge equipment includes a solid-liquid dust removal device and a conveying device connected together. The solid-liquid dust removal device is connected to the tail end of the rotary kiln, and the conveying device is connected to the downstream lithium extraction system.
[0025] By incorporating the aforementioned rotary kiln equipment into the battery black powder roasting and reduction system, the material is simultaneously roasted and pulverized within the kiln. This ensures that the roasted material discharged from the kiln meets the particle size requirements of subsequent processes. Simultaneously, it reduces the particle size requirements of the battery black powder entering the kiln from the feeding equipment. Even if the initial battery black powder particle size is uneven or some powder agglomerates, it can be promptly broken up within the kiln, ensuring the reduction effect of the battery black powder, enabling continuous operation, and improving production efficiency. Furthermore, the solid-liquid dust removal device receives the roasted material from the kiln's tail end, preventing dust generation and dispersion. This not only fully recovers the material and improves the lithium recovery rate but also improves the working environment. The solid-liquid dust removal device can also absorb the heat remaining in the roasted material, increasing the temperature of the slurry delivered to the downstream lithium extraction system, reducing the heating energy consumption of the downstream lithium extraction system, and lowering overall production costs.
[0026] In some embodiments, the conveying device includes an inclined pipe and a conveying pump, the outlet of the solid-liquid dust removal device is connected to the inlet of the inclined pipe, the outlet of the inclined pipe is connected to the inlet of the conveying pump, the outlet of the conveying pump is connected to the lithium extraction system, and the inclined pipe gradually rises along the material conveying direction.
[0027] With this setup, the slurry in the inclined pipe can flow back to the solid-liquid dust removal device during the downtime of the conveying pump. This ensures that there is no material accumulation in the inclined pipe and before the conveying pump is restarted, allowing the conveying pump to start under no-load or light-load conditions, quickly establish normal conveying pressure, improve the stability of system operation, and extend the service life of the conveying pump. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the rotary kiln equipment of the battery black powder calcination and reduction system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the arrangement of the crushing components inside the rotary kiln according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the limiting component provided in an embodiment of the present invention; Figure 4This is a schematic diagram of the overall structure of the battery black powder calcination and reduction system provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the conveying device provided in an embodiment of the present invention.
[0029] Figure label: 1. Power mechanism; 2. Rotary kiln; 21. Insulation layer; 3. Crushed parts; 4. Limiting components; 41. Circumferential ring; 42. Radial rod; 100. Feeding equipment; 200. Discharge equipment; 210. Solid-liquid dust removal device; 220. Conveying device; 221. Inclined pipe; 222. Conveying pump; 300. Rotary kiln equipment. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0031] The accompanying drawings illustrate layer structure diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.
[0032] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0033] Based on the background technology, in the lithium battery recycling process, the traditional roasting process using equipment such as rotary kilns can cause the roasted material to agglomerate during roasting. The agglomerated roasted material encapsulates a large amount of black powder inside the lumps, preventing it from being fully reduced, thus seriously affecting the lithium recovery rate. This invention provides a battery black powder roasting and reduction system and its rotary kiln equipment, which aims to crush the roasted material while roasting in the rotary kiln to improve the reduction effect of battery black powder and thus improve the lithium recovery rate.
[0034] SeeFigures 1 to 3 The first aspect of this invention provides a rotary kiln device for a battery black powder calcination and reduction system. The rotary kiln device 300 includes a power mechanism 1 and a rotary kiln 2. The power mechanism 1 is connected to the rotary kiln 2 to drive the rotary kiln 2 to rotate. The rotary kiln 2 provides a closed, controllable high-temperature environment and necessary residence time for black powder calcination, carries and transports materials, and promotes the reduction reaction of materials in the kiln through its own rotation. The rotary kiln 2 is provided with a freely placed crushing component 3, which is configured to be driven by the rotary kiln 2 to crush the materials in the rotary kiln 2, pulverizing large pieces of materials into small particles or powder. When the rotary kiln device 300 is running, the power mechanism 1 is mechanically connected to the rotary kiln 2, driving the rotary kiln 2 to rotate continuously around the axis of the rotary kiln 2, causing the black powder materials in the kiln to tumble and move forward together, and to carry out the calcination reaction at a set temperature. Here, the direction of the axis of the rotary kiln 2 specifically refers to the direction from the first end to the last end of the rotary kiln 2. The axis of the rotary kiln 2 is inclined at a certain angle relative to the horizontal line, for example, it can be 2° to 10°. The crushing component 3 is freely placed inside the rotary kiln 2. When the material forms hard, large lumps due to high-temperature sintering, these lumps move relative to the crushing component 3 located inside the kiln. Utilizing the mass and specific shape of the crushing component 3, such as rod-shaped or block-shaped, and since the crushing component 3 does not move synchronously with the material, it exerts crushing, impact, and kneading forces on the lumps under the drive of the rotary kiln 2, thereby crushing the large lumps into small particles. At the same time, the crushing component 3 continuously changes its contact point and action mode with the material as the kiln rotates, realizing dynamic and continuous crushing of the lumps and reducing the particle size of the material.
[0035] With this setup, a crushing component 3 is installed inside the rotary kiln 2 to crush the agglomerated material in real time. This exposes the black powder encased within the agglomerates, allowing it to fully contact the reducing agent and the high-temperature atmosphere, ensuring a complete reaction during roasting and thus improving lithium conversion efficiency. Simultaneously, the reduced particle size increases the specific surface area of the material, accelerating the reduction reaction rate. The smaller particle size of the roasted material also creates favorable conditions for subsequent processes. For example, when the roasted material enters the wet leaching process, it accelerates the leaching process, further improving the comprehensive recovery rate of valuable metals such as lithium, nickel, cobalt, and manganese, avoiding the need for separate crushing of the roasted material in existing technologies. Furthermore, continuous crushing of the material within the rotary kiln 2 ensures that the material remains loose, preventing blockages caused by excessive agglomeration and affecting normal material transport, thereby improving overall operational stability.
[0036] It should be noted that the specific structural form of the power mechanism 1 and the specific method of driving the rotary kiln 2 are not limited here. For example, the power mechanism 1 can be an electric motor or a hydraulic motor, and can be driven by gear meshing or roller friction, etc. Adaptive settings can be made according to actual application requirements to achieve stable rotation of the rotary kiln 2.
[0037] In some possible implementations, the crushing component 3 is arranged along the material conveying direction inside the rotary kiln 2. The length of the crushing component 3 is less than or equal to the length of the rotary kiln 2. That is, the crushing component 3 is set inside the rotary kiln 2, and its arrangement direction is basically consistent with the direction in which the material is conveyed from the feed end to the discharge end. Furthermore, the length of the crushing component 3 does not exceed the effective length of the rotary kiln 2. As long as the material is within the length range of the kiln body, it can come into contact with the crushing component 3. When the material sinters and forms agglomerates in the high-temperature zone, these agglomerates will be continuously subjected to the action of the crushing component 3 as they move towards the discharge end, thereby being crushed in a timely manner. This ensures the reduction effect and the uniformity and particle size of the discharged material. At the same time, it ensures that the crushing component 3 is stably installed inside the rotary kiln 2, avoiding problems with the kiln body balance or interference with other components due to excessive length, and ensuring stable operation of the equipment.
[0038] It should be noted that the specific structure of the crushing component is not limited here. It can involve placing a certain number of wear-resistant steel balls inside the rotary kiln 2. When the kiln rotates, the steel balls tumble and slide along with the material, breaking up the agglomerates through the squeezing, grinding, and impact between the balls and the material. In a preferred embodiment, the crushing component 3 includes multiple roller bars located at the inner bottom of the rotary kiln 2. These roller bars can rotate freely with the rotary kiln 2; that is, they do not require separate drive components. During the rotation of the rotary kiln 2, the roller bars are directly driven to rotate. Utilizing the mass and strength of the rod-shaped structure, the agglomerated material is efficiently crushed and ground. The combined action of the multiple roller bars forms a crushing zone at the inner bottom of the rotary kiln 2. As the rotary kiln rotates, its bottom is the main area for material accumulation and conveying. The rollers also fall onto the material layer or directly contact the kiln bottom due to gravity. As the kiln rotates, the rollers roll under gravity, crushing and impacting the material below. When the rotary kiln has a certain degree of inclination, setting the crushing components in a rod-shaped form allows for uniform distribution of the crushing components inside the rotary kiln, resulting in more uniform material crushing. Using multiple rollers increases the contact points and frequency of action with the material. When the kiln rotates, different rollers will act on the material alternately and repeatedly, forming a dynamic, high-frequency crushing environment, improving crushing efficiency and effectiveness.
[0039] The specific layout of multiple roller bars within the rotary kiln 2 is not limited here; they can be stacked or layered, as long as the crushing function can be achieved.
[0040] The rollers here can be solid or hollow, as long as they meet the above-mentioned crushing effect. In the preferred case, provided that the outer diameter and structural strength are sufficient to withstand the crushing impact, the rollers are hollow. This can effectively reduce the overall mass of the rollers, and the torque and power required by the rotary kiln 2 to drive the rollers are reduced accordingly. The rollers rotate more flexibly, and the load and energy consumption of the power mechanism 1 are also reduced. More importantly, under the same mass, the hollow structure of the rollers can increase the outer diameter of the rollers, thereby increasing the contact area between the material and the rollers, improving the effect of single crushing, and further improving the crushing efficiency.
[0041] In some possible implementations, the outer diameter of the hollow roller bar is 0.008-0.4 times the inner diameter of the furnace of the rotary kiln 2. Roller bars within this outer diameter range can reduce interference with the thermal field inside the furnace, make the hot air flow distribution more uniform, ensure that the material is heated consistently, and improve the roasting quality.
[0042] In some possible implementations, the surface of the roller bar is coated with a tungsten carbide coating, that is, a 2-4mm high-temperature resistant, wear-resistant, and corrosion-resistant tungsten carbide coating is applied to the surface of the roller bar. This effectively resists long-term, high-intensity friction and impact from black powder and agglomerated materials, delays the wear of the roller bar, and allows the roller bar to maintain its own geometry for a long time, thereby maintaining a stable crushing effect. At the same time, it protects the internal matrix material from the erosion of high temperature and corrosive atmosphere, prevents the structural strength from decreasing or even failing due to corrosion, improves the service life of the roller bar, reduces the replacement frequency of the roller bar, and reduces maintenance costs.
[0043] In some possible implementations, a limiting component 4 is provided at the tail end of the rotary kiln 2. The limiting component 4 is configured to prevent the roller bars from moving out of the rotary kiln 2 and to allow the material in the rotary kiln 2 to flow out from its tail end. That is, by using the limiting component 4 as a blocking structure, the roller bars are prevented from being discharged from the rotary kiln 2 along with the material. Furthermore, it can also be configured to form a screen-like structure through its own structure, which not only achieves the blocking effect, but also allows only the calcined material that meets the particle size requirements to pass through, achieving a screening effect. The limiting component 4 allows the roller bars to be permanently retained in the rotary kiln 2, avoiding the problem of axial misalignment of the roller bars or even one end moving out of the rotary kiln 2, resulting in frequent shutdowns for maintenance. Furthermore, the limiting component 4 can also achieve the limiting of the roller bars and the screening of the calcined material in the same spatial position, i.e., at the tail end of the rotary kiln 2, through simple physical size screening. This makes the tail end structure of the rotary kiln 2 compact, allowing the calcined material to be discharged smoothly, ensuring production continuity, while the roller bars are confined to the working area, ensuring the crushing effect.
[0044] It should be noted that the specific structure of the limiting component 4 is not limited here. In some possible implementations, the crushing component 3 can be limited by directly contacting the tail end of the rotary kiln 2. For example, the tail end of the rotary kiln 2 can be configured with a converging structure, that is, a contracting boss structure can be provided at the tail end of the rotary kiln 2 facing into the kiln cavity. The crushing component 3 directly contacts the boss structure, and the boss structure limits the crushing component 3. In this case, the limiting component 4 includes a contracting boss structure, which achieves the blocking effect on the rollers.
[0045] In other possible implementations, a mesh structure can be used, where one or more meshes with arrayed through holes are installed at the tail end of the rotary kiln 2. The meshes are fixedly connected to the kiln body, and the aperture of the meshes is designed to be smaller than the diameter of the ends of the rollers but larger than the required particle size of the roasted material. The rollers are blocked by the mesh as a whole, and the material is discharged through the holes. Alternatively, a grid structure composed of circumferential rings 41 and radial rods 42 can be used. The maximum size of the grid openings is smaller than the diameter of the ends of the rollers but larger than the required particle size of the roasted material. Here, the circumferential rings 41 can be a single ring or multiple rings located on the same plane. The circumferential rings 41 can be integrally formed or formed by splicing multiple arc-shaped structures. The grid structure can also be a single layer or arranged in multiple layers along the rotary kiln 2. In this case, the limiting component 4 not only achieves the blocking function but also plays a certain screening role.
[0046] In some specific examples, the limiting component 4 includes multiple circumferential rings 41 and multiple radial rods 42. The diameters of the circumferential rings 41 are different, forming the main frame of the limiting component 4. All the circumferential rings 41 are concentrically arranged, and the multiple circumferential rings 41 are connected by multiple radial rods 42 distributed circumferentially, forming a multi-layered annular blocking surface. The multiple circumferential rings 41 and multiple radial rods 42 form multiple openings. The maximum opening distance of each opening is less than the minimum length of the cross-section of the roller bar. That is, multiple concentric rings are welded or fixed together by several radial rods 42 distributed circumferentially, forming a circular structure similar to a wheel or grid, installed at the tail end of the rotary kiln 2. The inner ends of all radial rods 42 are connected and coincide with the center of the circumferential rings 41. The outer end of each radial rod 42 extends radially and connects sequentially to the circumferential rings 41 with diameters increasing from small to large, forming a grid barrier. The size of the roller bar is greater than the maximum opening distance of each opening. Here, the cross-section of the roller bar specifically refers to the section perpendicular to the axis of the roller bar, and its minimum length is greater than the maximum opening distance of the opening. Figure 2 and Figure 3As shown, the minimum length W1 of the roller cross-section and the maximum opening distance W2 of the through-hole satisfy W1 being greater than W2, ensuring that the roller is confined within the rotary kiln 2. The crushed fine calcined material can easily pass through these grid through-holes and be discharged outside the rotary kiln 2. In addition, the annular reinforcing structure formed by multiple circumferential rings 41, while the radial rods 42 distributed along the circumference, serve as supports and connections, linking the various circumferential rings 41 into a solid whole. Under repeated, high-intensity impact loads, it has higher rigidity and fatigue resistance, ensuring the reliability of the positioning component over a long period of time. The concentric design of the circumferential rings 41 makes the overall structure uniformly stressed, extending the service life of the positioning component 4.
[0047] The following describes the possible ways in which the end face shape of the roller bar and the limiting component 4 can be matched. In some possible embodiments, the end face of the roller bar is either flat or curved. Those skilled in the art can flexibly set it according to the internal structure of the rotary kiln 2 in practical applications. For example, when the limiting component 4 is set at the tail end of the rotary kiln 2, and the limiting component 4 is a combination of multiple circumferential rings 41 and multiple radial rods 42 as described above, the end face of the roller bar contacts the limiting component 4. In some preferred examples, the end face of the roller bar is flat. The flat surface can prevent the roller bar from getting stuck at the opening, allowing the roller bar to roll more freely. For example, when the tail end of the rotary kiln 2 is provided with a shrinking boss structure, the end face of the roller bar directly contacts the side wall of the boss structure of the rotary kiln 2. In some preferred examples, the end face of the roller bar is an arc surface. The arc surface can be a partially arc-shaped structure at the center of the end of the roller bar, or it can be a spherical structure formed by the entire end face. The contact between the arc-shaped end face and the interior of the rotary kiln 2 is a point contact or a small area contact, which reduces the contact area. At the same time, the arc surface can reduce stress concentration, thereby reducing the frictional resistance and end face wear during relative sliding.
[0048] In some possible implementations, the inner wall of the rotary kiln 2 is provided with a heat insulation layer 21, that is, the heat insulation layer 21 covers one or more layers of refractory heat insulation material on the inner wall of the rotary kiln 2, reducing the loss of heat from the kiln to the external environment, maintaining a stable high-temperature roasting environment inside the kiln, and retaining the heat generated by the roasting reaction to the maximum extent inside the furnace. By reducing heat loss, the energy requirement for maintaining the furnace temperature is reduced, thereby reducing energy costs in the production process; at the same time, the heat insulation layer 21 reduces the impact of external temperature fluctuations on the temperature field inside the kiln, making it easier to maintain a stable and uniform roasting temperature inside the kiln, preventing incomplete roasting and reduction due to temperature changes, and ensuring the uniformity and stability of black powder reduction; in addition, the heat insulation layer 21 forms a heat insulation barrier between the high-temperature material and the inner wall of the rotary kiln 2, reducing the temperature borne by the inner wall of the rotary kiln 2 itself, and extending the service life of the rotary kiln equipment 300.
[0049] See Figures 1 to 5Another aspect of the present invention provides a battery black powder calcination and reduction system. The system includes a feeding device 100, a discharging device 200, and the aforementioned rotary kiln device 300. The feeding device 100 is connected to the first end of the rotary kiln 2 and is responsible for stably and controllably conveying and feeding the battery black powder raw material to be processed into the first end of the rotary kiln 2. The rotary kiln device 300 completes the calcination and reduction of the black powder and the crushing of the material. The discharging device 200 is responsible for receiving the calcined powder discharged from the last end of the rotary kiln 2, processing the calcined material, and conveying it to the downstream lithium extraction system. The lithium extraction system here refers to a lithium extraction process system outside the reduction system and can be adapted to production needs; no limitations are imposed here. The discharge equipment 200 includes a solid-liquid dust removal device 210 and a conveying device 220 connected together. The solid-liquid dust removal device 210 is connected to the tail end of the rotary kiln 2 and is used to receive the roasted powder and process it by wet method, that is, to mix the roasted powder and the liquid in the solid-liquid dust removal device 210 to eliminate dust and recover waste heat. The conveying device 220 is connected to the downstream lithium extraction system and conveys the slurry formed in the solid-liquid dust removal device 210 to the downstream lithium extraction system.
[0050] During system operation, black powder is fed into the rotary kiln 2 from the head end via the feeding equipment 100, such as a hopper or auger. The material undergoes high-temperature roasting inside the rotary kiln 2, while the crushing components 3 inside the kiln crush the generated agglomerates in real time. The roasted powder with residual heat after crushing is discharged from the kiln tail and directly enters the solid-liquid dust removal device 210 of the discharge equipment 200. The roasted powder is mixed with water or other liquids added to the solid-liquid dust removal device 210 to quickly form a slurry, eliminating the dust generated during dry powder conveying and reducing the loss of roasted powder. Furthermore, the residual heat of the roasted powder is directly transferred to the slurry, raising the temperature of the slurry. The heated slurry is then extracted from the solid-liquid dust removal device 210 by the conveying device 220 and transported to the downstream lithium extraction system for direct use in subsequent lithium extraction processes. This can reduce the energy consumption of heating the slurry in the lithium extraction system's own processes.
[0051] With this setup, the rotary kiln equipment 300 described above is configured in the battery black powder roasting and reduction system. The efficient reduction roasting and material crushing tasks are simultaneously completed in the rotary kiln 2, ensuring that the roasted material discharged from the tail end of the rotary kiln 2 meets the particle size requirements of subsequent processes. Furthermore, the particle size restrictions on battery black powder entering the rotary kiln 2 from the feeding device 100 are relaxed. Even if the initial battery black powder particle size is uneven or some battery black powder is agglomerated, it can be quickly broken up inside the rotary kiln 2, ensuring the reduction effect of the battery black powder, achieving continuous operation, and improving production efficiency. In addition, the solid-liquid dust removal device 210 receives the roasted material conveyed from the tail end of the rotary kiln 2, preventing dust generation and dispersion. It can comprehensively recover materials, improving the recovery rate of high-value elements such as lithium, nickel, cobalt, and manganese, and optimize the working environment. The solid-liquid dust removal device 210 can also absorb the residual heat of the roasted material in a timely manner, increasing the slurry temperature delivered to the downstream lithium extraction system, reducing the heating energy consumption of the downstream lithium extraction system, and reducing overall production costs.
[0052] The specific connection method between the rotary kiln equipment 300 and the discharge equipment 200 is not limited here. The discharge port of the rotary kiln equipment 300 can be directly connected to the feed port of the discharge equipment 200, or it can be connected by setting a screw conveyor or other structures.
[0053] In some possible implementations, the conveying device 220 includes an inclined pipe 221 and a conveying pump 222. The outlet of the solid-liquid dust removal device 210 is connected to the inlet of the inclined pipe 221, the outlet of the inclined pipe 221 is connected to the inlet of the conveying pump 222, and the outlet of the conveying pump 222 is connected to the lithium extraction system. The inclined pipe 221 gradually rises along the material conveying direction, that is, the inclined pipe 221 is lower near the inlet of the solid-liquid dust removal device 210 and higher near the outlet of the conveying pump 222. The conveying pump 222 draws the slurry from the solid-liquid dust removal device 210 and conveys it to the downstream lithium extraction system. When the conveying pump 222 stops, the slurry can flow back to the solid-liquid dust removal device 210 through the inclined pipe 221, which minimizes the amount of material residue in the inclined pipe 221 and the conveying pump 222 before the next start-up, avoids the problem of blockage in the inclined pipe 221, and allows the conveying pump 222 to start under no-load or light-load conditions, quickly reach the normal conveying pressure, improve the system's operational stability and the service life of the conveying pump 222.
[0054] In some possible implementations, the angle between the inclined section of the inclined pipe 221 and the vertical plane is 25-75°, as can be referred to Figure 5 The included angle α ensures a certain return angle for reliable return while preventing the inclined pipe 221 from becoming too vertical and increasing the workload of the delivery pump 222, thus guaranteeing stable slurry delivery. The projected length of the inclined section of the inclined pipe 221 on the horizontal plane is between 10-30 cm. This projected length on the horizontal plane can be found in [reference needed].Figure 5 The horizontal distance L is set to ensure that the layout of each device is close together, preventing concentration fluctuations or additional energy consumption caused by the back-and-forth flow of a large amount of slurry.
[0055] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.
Claims
1. A rotary kiln device for a battery black powder calcination and reduction system, characterized in that, The rotary kiln equipment (300) includes a power mechanism (1) and a rotary kiln (2). The power mechanism (1) is connected to the rotary kiln (2) to drive the rotary kiln (2) to rotate. The rotary kiln (2) is provided with a crushing component (3). The crushing component (3) is configured to be driven to crush the material in the rotary kiln (2) when the rotary kiln (2) rotates.
2. The rotary kiln equipment of the battery black powder roasting and reduction system according to claim 1, characterized in that, The crushing component (3) is arranged along the material conveying direction inside the rotary kiln (2), and the length of the crushing component (3) is less than or equal to the length of the rotary kiln (2).
3. The rotary kiln equipment of the battery black powder calcination and reduction system according to claim 2, characterized in that, The crushing component (3) includes multiple roller bars, which rotate freely with the rotary kiln (2).
4. The rotary kiln equipment of the battery black powder calcination and reduction system according to claim 3, characterized in that, The roller bars are hollow roller bars; and / or The surface of the rollers is coated with a tungsten carbide coating.
5. The rotary kiln equipment of the battery black powder roasting and reduction system according to claim 3, characterized in that, The end faces of the roller bars are either flat or curved.
6. The rotary kiln equipment of the battery black powder calcination and reduction system according to claim 3, characterized in that, The rotary kiln (2) is provided with a limiting component (4) at its tail end. The limiting component (4) is configured to prevent the roller bar from moving out of the rotary kiln (2) and to allow the material in the rotary kiln (2) to flow out from its tail end.
7. The rotary kiln equipment of the battery black powder calcination and reduction system according to claim 6, characterized in that, The limiting component (4) includes multiple circumferential rings (41) and multiple radial rods (42). Each of the circumferential rings (41) has a different diameter. All the circumferential rings (41) are concentrically arranged and the multiple circumferential rings (41) are connected by multiple radial rods (42) distributed along the circumference. The multiple circumferential rings (41) and the multiple radial rods (42) form multiple openings. The maximum opening distance of each opening is less than the minimum length of the cross section of the roller bar.
8. The rotary kiln equipment of the battery black powder roasting and reduction system according to claim 1, characterized in that, The inner wall of the rotary kiln (2) is provided with a heat insulation layer (21).
9. A battery black powder calcination and reduction system, characterized in that, The battery black powder roasting and reduction system includes a feeding device (100), a discharging device (200), and a rotary kiln device (300) as described in any one of claims 1 to 8. The feeding device (100) is connected to the head end of the rotary kiln (2); The discharge equipment (200) includes a solid-liquid dust removal device (210) and a conveying device (220) connected together. The solid-liquid dust removal device (210) is connected to the tail end of the rotary kiln (2), and the conveying device (220) is connected to the downstream lithium extraction system.
10. The battery black powder calcination and reduction system according to claim 9, characterized in that, The conveying device (220) includes an inclined pipe (221) and a conveying pump (222). The outlet of the solid-liquid dust removal device (210) is connected to the inlet of the inclined pipe (221), the outlet of the inclined pipe (221) is connected to the inlet of the conveying pump (222), and the outlet of the conveying pump (222) is connected to the lithium extraction system. The inclined pipe (221) gradually rises along the material conveying direction.