Roasting system of waste battery powder and roasting method thereof

Abstract

The invention relates to a roasting system and method for waste battery powder, and the system comprises a gas-solid mixer which is provided with a first inlet, a gas inlet and a first outlet; the disturbance enhancing assembly comprises a first barrel, a rotating shaft, a second inlet and a second outlet, the second inlet and the second outlet are formed in the first barrel, and a plurality of paddles are arranged on the rotating shaft; the second inlet is communicated with the first outlet; an inlet of the gas-solid separator is communicated with the second outlet; a feeding hole of the roasting furnace is communicated with a discharging hole of the gas-solid separator through a feeding mechanism; the indirect heat exchanger is provided with a first medium inlet, a first medium outlet, a second medium inlet and a second medium outlet, the first medium inlet is communicated with the exhaust port of the roasting furnace, and the second medium outlet is connected with the gas-solid mixer and the roasting furnace in parallel. The roasting system has the advantages of being high in raw material conveying smoothness, low in energy consumption, good in roasting effect, environmentally friendly and the like, and the industrial application prospect is good.

Description

Technical Field

[0001] This invention relates to a roasting system and method for waste battery powder, belonging to the field of solid waste resource utilization. Background Technology

[0002] With the explosive growth of the new energy vehicle market, the first batch of power batteries for new energy vehicles has entered its aging stage, leading to a "retirement wave" of power batteries. If these retired power batteries are not properly disposed of, they will pose a great threat to the environment and safety. Therefore, the recycling and utilization of power batteries has become a pain point and a hot issue in the current rapid development of the industry.

[0003] Waste lithium battery powder is typically the powdery substance obtained after pre-treatment processes such as dismantling (optional steps), crushing, and screening of waste lithium batteries. It mainly includes waste lithium battery powder, positive and negative electrode mixed powder, positive electrode powder, or a mixed powder containing the aforementioned materials. Roasting of waste lithium battery powder is a common process in the current resource recovery of waste lithium battery powder. One common method involves heating the waste lithium battery powder with air to a roasting temperature, where the powder reacts with oxygen in the air, releasing a large amount of heat energy. This heating process requires the absorption of a significant amount of heat. Therefore, the development of waste lithium battery powder roasting technology is crucial to the processing and recycling of retired batteries from new energy vehicles and is vital to the development of the waste battery processing industry.

[0004] Chinese invention patent specification CN117691230A discloses a pretreatment method and a wet recycling method for waste lithium iron phosphate battery black powder. The pretreatment method includes the following steps: placing the waste lithium iron phosphate battery black powder in a rotary heating furnace and roasting it in an air atmosphere, and obtaining roasted material after roasting. The pretreatment method is used for the pretreatment of waste lithium iron phosphate battery black powder before wet recycling. It mainly uses an air atmosphere roasting method to oxidize the divalent iron in the black powder to trivalent iron, while removing impurities such as binders and carbon black. Therefore, although the subsequent wet recycling does not require the use of oxidants and organic solvents, greatly reducing the amount of waste liquid, it does not focus on optimizing the roasting process. Low-temperature materials are directly roasted at a high temperature of 600-800℃. The large temperature difference between the material and the heating medium in the roasting furnace results in low roasting efficiency and poor roasting effect, which can easily cause defects such as sintering material caking and furnace wall ring formation. In addition, during the roasting process, organic matter such as binders and electrolytes react under high temperature conditions to produce dioxins, hydrogen fluoride, and tar, which are toxic and harmful gases. The aforementioned gases or substances are not diverted or optimized; instead, they pass sequentially through dust collectors, heat exchangers, and other downstream equipment along with the roasting dust. This not only causes corrosion damage and blockage risks to subsequent processing equipment but also increases the burden, difficulty, and cost of subsequent exhaust gas treatment. Furthermore, the aforementioned organic matter undergoes competitive reactions during roasting, which is detrimental to the material roasting reaction, complicates the reaction, reduces controllability, and makes it difficult to guarantee roasting stability. Additionally, the tar substances produced during the decomposition of organic matter during roasting adhere to the reaction surfaces of subsequent high-temperature dust collectors and other equipment, making them difficult to remove, affecting work efficiency and the service life of high-temperature dust collectors, and increasing the risk of material agglomeration, which is detrimental to the full and efficient roasting reaction. Moreover, this patent application does not consider how to transport materials into the rotary kiln or how to save processing energy, resulting in low energy utilization.

[0005] Chinese invention patent application CN118272656A discloses a recycling system for valuable metals from waste nickel-cobalt-manganese lithium batteries, including a feeding unit, a preheating and dehydration unit, a roasting and oxidation unit, a smelting unit, a zinc powder recovery unit, and a waste gas treatment unit. The preheating and dehydration unit includes a dryer, a primary cyclone preheater, and a secondary cyclone preheater. The feed inlet of the dryer is connected to the feeding unit, and the material-carrying airflow outlet of the dryer is connected to the feed inlet of the primary cyclone preheater. The exhaust pipe of the secondary cyclone preheater is connected to the airflow inlet of the dryer. The roasting and oxidation unit includes a roasting furnace and a cyclone heating furnace. The feed inlet of the roasting furnace is connected to the discharge pipe of the secondary cyclone preheater, the material-carrying airflow outlet of the roasting furnace is connected to the feed inlet of the cyclone heating furnace, the exhaust pipe of the cyclone heating furnace is connected to the feed inlet of the secondary cyclone preheater, and the discharge pipe of the primary cyclone preheater is connected to the exhaust pipe of the cyclone heating furnace. The system has a complex individual and overall structure. The preheating and calcination stages require sequential installation of a Venturi dryer, a primary cyclone preheater, and a secondary cyclone preheater. This is not only expensive, but the Venturi dryer's narrow pipes require high material dispersion and cannot handle agglomerated materials, otherwise it is prone to clogging the feeder. Furthermore, its drying efficiency is low, making it difficult to meet the demands of high-efficiency industrial production. The secondary cyclone preheating stages also require separate gas-solid separation, resulting in complex gas-solid piping, high energy consumption, high failure rate, and low operating efficiency. The calcination stage involves roasting... The roasting process involves sequential roasting in a furnace and a cyclone heating furnace, resulting in complex equipment, high operating and maintenance costs, and a high failure rate. Furthermore, the short preheating path (time) of the primary and secondary cyclone furnaces and the direct heat exchange between the high-temperature roasting exhaust gas and the material make it easy to cause uneven and insufficient preheating of the material, which has limited beneficial effects on subsequent roasting. At the same time, the formation of local high temperatures causes organic matter to decompose, producing tar and other substances that adhere to the working surface of the cyclone dust collector, causing blockage of the cyclone dust collector and increasing the risk of material agglomeration or clumping, which is not conducive to the full and efficient roasting reaction. Summary of the Invention

[0006] In view of the shortcomings of the prior art, one of the objectives of this invention is to provide a roasting system for waste battery powder with low energy consumption and good roasting effect; another objective of this invention is to provide a roasting method for waste battery powder.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] A calcination system for waste battery powder includes:

[0009] A gas-solid mixer, which is provided with a first inlet, an air inlet and a first outlet;

[0010] At least one disturbance enhancement component, the disturbance enhancement component includes a first cylinder, a rotating shaft disposed within the first cylinder, a second inlet and a second outlet disposed on the first cylinder, the rotating shaft extending along the length direction of the first cylinder, and having a plurality of blades disposed on the rotating shaft, the plurality of blades being sequentially distributed along the length direction of the rotating shaft; the second inlet is connected to the first outlet;

[0011] A gas-solid separator, wherein the inlet of the gas-solid separator is connected to a second outlet;

[0012] The roasting furnace, whose inlet is connected to the outlet of the gas-solid separator via a feeding mechanism; and

[0013] An indirect heat exchanger has a first medium inlet, a first medium outlet, a second medium inlet, and a second medium outlet. The first medium inlet and the first medium outlet are interconnected, as are the second medium inlet and the second medium outlet. The first medium inlet is connected to the roasting flue gas outlet. Preferably, the first medium outlet is connected to a tail gas treatment unit. The second medium outlet is connected in parallel to a first valve and a second valve. The outlet of the first valve is connected to the inlet of a gas-solid mixer, and the outlet of the second valve is connected to the inlet of a roasting furnace.

[0014] In this way, the high-temperature flue gas generated during the air roasting process of waste battery powder in the roasting furnace can exchange heat with air in the indirect heat exchanger to cool down the high-temperature flue gas, facilitating subsequent treatment and emission. At the same time, part of the hot air generated by the indirect heat exchanger enters the gas-solid mixer, where the hot air is initially mixed, dispersed, and preheated with the waste battery powder, so that the waste battery powder is fully dispersed and suspended in the hot air to form a gas-solid coarse mixture. Subsequently, the gas-solid coarse mixture enters the disturbance enhancement component and is distributed sequentially along the length of the rotating shaft. Multiple blades generate strong disturbances to the gas-solid coarse mixture, enhancing its turbulence intensity. The coarse particles of waste battery powder are further and repeatedly dispersed, exposing new surfaces. This effectively promotes the volatilization and separation of residual electrolytes, binders, and other organic matter in the waste battery powder, thereby obtaining fine waste battery powder with good flowability, low organic content, and low agglomeration. This effectively improves the smoothness of pneumatic conveying, reduces the possibility of blockage of pipelines and other components during the conveying of waste battery powder to the roasting furnace, and eliminates the need for gas-solid separation during preheating. The equipment and operation are simple, efficient, and have a low failure rate.

[0015] In addition, during the process of conveying waste battery powder to the roasting furnace, there is no need to worry about the waste battery powder being squeezed or agglomerated, thus affecting the subsequent roasting effect.

[0016] During roasting, preheated and fully dispersed waste battery powder and hot air are simultaneously fed into the roasting furnace. The waste battery powder and hot air only need to absorb a small amount of heat to quickly reach the temperature required for the roasting reaction, which helps to reduce the required heating time and heating energy consumption, thereby effectively saving energy, realizing the recycling of heat, and improving energy utilization.

[0017] Moreover, the particle size of the input waste battery powder has been further refined and the amount of organic matter it contains is quite low. The waste battery powder and its active materials can come into more full contact with hot air, and the competitive reaction between organic matter and air is greatly reduced, thereby making the roasting reaction more efficient and thorough, thus effectively improving roasting efficiency and roasting fullness, and obtaining better roasting effect.

[0018] In addition, the roasting reaction stage is a high-temperature reaction stage. Since the amount of organic matter contained in the waste battery powder is already quite low, the possibility of toxic and harmful gases such as fluorides, nitrogen oxides, and dioxins produced by the oxidation and combustion reaction of organic matter in this stage is greatly reduced. This effectively reduces the amount of toxic and harmful gases in the high-temperature flue gas, making it more green and environmentally friendly, and can also greatly reduce the burden and cost of subsequent exhaust gas treatment.

[0019] As can be seen, the roasting system of the present invention uses an indirect heat exchanger to exchange heat between high-temperature flue gas and air, and utilizes a portion of the hot air for pneumatic conveying and pretreatment of waste battery powder, as well as for air roasting. This improves the smoothness of waste battery powder conveying and solves the raw material conveying problem faced in industrial processing. Simultaneously, it achieves full recycling of heat, which is beneficial for energy conservation and consumption reduction. Furthermore, the air roasting effect of waste battery powder is better, and the generation of toxic and harmful gases is lower. Therefore, the roasting system of the present invention has good prospects for industrial application and is conducive to realizing the industrial roasting treatment of waste battery powder.

[0020] In waste battery powder processing enterprises, the raw material workshop used to store waste battery powder is usually some distance away from the roasting workshop. Furthermore, waste battery powder is a toxic waste material, unsuitable for transfer by conveyor belts or manual transport by feeding trolleys. This invention effectively solves the problem of transferring and conveying waste battery powder between different workshops through pneumatic conveying, without causing dust pollution and with high efficiency. Simultaneously, the hot air produced by the indirect heat exchanger not only achieves pneumatic conveying of the waste battery powder but also preheats and disperses it during pneumatic conveying, helping to ensure smooth pneumatic conveying and improving subsequent roasting efficiency and completeness.

[0021] Furthermore, the second inlet is located at or near one end of the first cylinder, and the second outlet is located at or near the other end of the first cylinder. This ensures the residence time of the material within the first cylinder and the frequency of collisions with components such as the paddles, thereby guaranteeing a good dispersing and homogenizing effect.

[0022] Furthermore, the angle between the axial direction of the first cylinder and the horizontal plane is 45°-90°, further to 60-90°, and even further to 75-90°.

[0023] Furthermore, the location of the second export is higher than the location of the second import.

[0024] Furthermore, the gas-solid mixer includes a second cylinder with an inlet end and an outlet end distributed along the axial direction. A first inlet, an air inlet, and a first outlet are all disposed on the second cylinder. The first inlet is located at or near the inlet end of the second cylinder, the air inlet is located at or near the inlet end of the second cylinder, and the first outlet is located at or near the outlet end of the second cylinder.

[0025] Furthermore, the angle between the axial direction of the second cylinder and the horizontal plane is 0°-30°, further to 5-25°, and even further to 10-20°.

[0026] Furthermore, the location of the first export is higher than the location of the first import.

[0027] In this way, fully dispersed materials can be transported smoothly, while agglomerated materials or materials with larger particle sizes remain at the front end of the gas-solid mixture or in the lower part of the first cylinder due to their own gravity. Only after continuous airflow disturbance and mechanical dispersion can they be transported to the downstream side.

[0028] Furthermore, a stirring mechanism is provided inside the second cylinder, and the gas-solid mixer is provided with multiple dispersing blades arranged along the axial direction of the stirring mechanism.

[0029] Furthermore, the length of the plurality of dispersing blades decreases first and then increases along the material transport direction within the gas-solid mixer, and the density of the plurality of dispersing blades along the axial direction of the stirring mechanism increases sequentially along the material transport direction within the gas-solid mixer.

[0030] Therefore, the lengths of the multiple dispersing blades are distributed in a zigzag pattern, first decreasing and then increasing, while the density of the dispersing blades increases sequentially. Through the coordination of blade length and density, the material and hot air are fully mixed and heat transferred, while the lumpy material is effectively broken up, and the material conveying space is fully guaranteed.

[0031] Furthermore, the blade comprises at least two blades, preferably three blades; the at least two blades are evenly distributed circumferentially along the axis of rotation;

[0032] Preferably, the blades of axially adjacent blades are staggered, which can further enhance the turbulence and flow path of the material flow within the disturbance enhancement component, and further increase the collision and contact opportunities between the powder and the blades, thereby further improving the heating and volatilization separation effect of organic matter.

[0033] Preferably, the blades are inclined circumferentially along the shaft, so that the angle between the width direction of the blades and the cross section of the first cylinder is 30-60°. In this way, while ensuring the disturbance effect, the effective suction is increased when the shaft drives the blades to rotate, so that the material flows more smoothly in the disturbance enhancement component, and at the same time, the waste battery powder is prevented from accumulating at the blades.

[0034] Preferably, the disturbance enhancement component further includes a drive mechanism connected to the shaft drive, thereby allowing the shaft speed to be controlled as needed.

[0035] Furthermore, the second medium outlet is connected to a first valve, a second valve, and a third valve. The rotating shaft is a hollow tube, and the outlet of the third valve is rotatably connected to one end of the rotating shaft, while the other end of the rotating shaft is sealed. The blade has a cavity that is connected to the rotating shaft, and multiple air holes connected to the cavity are opened on the blade. Thus, hot air enters the rotating shaft and flows out through the air holes on the blade. On the one hand, this can increase the temperature of high thermal conductivity components such as the rotating shaft and blades, and achieve solid-solid heat transfer through the collision and contact between the material and the blade components, so as to heat the waste battery powder more fully and further improve the volatilization and separation effect of organic matter such as binder and electrolyte. On the other hand, when the hot air is ejected from the air holes on the blade, it will create another dimension of impact on the material flow in the disturbance enhancement component, further increasing its flow turbulence, which helps to make full use of the energy in the air to improve the dispersion and heating effect, further promote the separation of organic matter, and fully prepare for the next stage of roasting. In addition, the hot air introduced through the third valve can dilute the original gas-solid mixture, reduce the concentration of volatile substances in the gas phase, and lower its partial pressure, which helps the volatile substances in the waste battery powder to volatilize more fully.

[0036] Hot air is used in two stages to classify, disperse, and preheat waste battery powder. The material is further preheated to a higher temperature (200-300℃) within the perturbation enhancement component. Through the cooperation of the gas-solid mixer and the perturbation enhancement component, mass transfer, heat transfer, and reaction are effectively optimized. This promotes the concentrated and thorough volatilization and separation of organic matter within the perturbation enhancement component. After separation by the gas-solid separator, the resulting gas is directly sent to the exhaust gas treatment device, effectively reducing corrosion and clogging of other equipment. During roasting, the preheated and thoroughly dispersed waste battery powder and hot primary air are simultaneously input into the roasting furnace. The waste battery powder and hot air only need to absorb a small amount of heat to quickly reach the temperature required for the roasting reaction, helping to reduce the required heating time and energy consumption, thereby effectively saving energy, achieving heat recycling, and improving energy efficiency.

[0037] Preferably, from the second inlet to the second outlet, the number of air holes on each blade gradually increases. As a result, the high-temperature airflow is ejected at high speed from the small holes in the blades, and the hot air forms a stable or increasing output flow in the direction from the inlet to the outlet. On the one hand, near the second outlet, the hot air carrying sufficient heat is ensured to exchange heat with the material that has been preheated to a certain extent in the early stage, maximizing the use of the heat in the preheated air and ensuring that the material is heated sequentially in the forward direction, reducing the temperature difference between the material and the hot air at the second outlet. On the other hand, the material is able to carry a sufficient amount of hot air into the gas-solid separator stage, reducing the temperature drop in the gas-solid separation stage, so as to better improve the subsequent roasting effect.

[0038] Furthermore, the number of disturbance enhancement components is two or more; the gas-solid mixer, each disturbance enhancement component, and the gas-solid separator are connected in series, or the disturbance enhancement components are connected in parallel between the gas-solid mixer and the gas-solid separator. Thus, by setting multiple disturbance enhancement components in parallel or series, the preheating, dispersion, and pyrolysis effects can be improved, or the feed flow rate can be enhanced, thereby increasing processing efficiency and ensuring smooth system operation. In addition, different tilt angles can be set for different disturbance enhancement components; for example, some disturbance enhancement components can be set vertically, and some can be set horizontally, to further enhance the disturbance effect.

[0039] Preferably, the gas-solid mixer is a centrifugal stirring mixer.

[0040] Furthermore, it also includes an exhaust gas treatment unit connected to the exhaust port of the gas-solid separator. Preferably, a first fan is provided between the exhaust port of the gas-solid separator and the exhaust gas treatment unit. Optionally, the first fan can be located in other positions, such as upstream of the gas-solid separator. Optionally, additional fans can also be added in other positions as needed.

[0041] Furthermore, it also includes a transition chamber connected to the outlet of the gas-solid separator, the bottom of which has a third outlet, which is connected to the inlet of the feeding mechanism via a fourth valve; preferably, the feeding mechanism is a screw feeding mechanism. This serves as a buffer and blocks the outlet of the gas-solid separator, causing the gas inside the gas-solid separator to flow towards its exhaust port and preventing gas from the calcining furnace from entering the gas-solid separator.

[0042] Furthermore, the roasting furnace is a rotary heating furnace, which is suitable for continuous feeding and continuous discharging to achieve continuous roasting processing. It can be combined with functional units such as gas-solid mixers, disturbance enhancement components, gas-solid separators, and indirect heat exchangers to form a continuous processing roasting system that can continuously feed and continuously discharge, thereby improving processing efficiency and better meeting the needs of industrial applications.

[0043] Preferably, the rotary heating furnace includes a rotary cylinder assembly and a discharge hood rotatably connected to the discharge end of the rotary cylinder assembly, and the feeding mechanism and the second valve are both connected to the feed end of the rotary cylinder assembly;

[0044] More preferably, the bottom of the discharge hood is provided with a roasting material outlet, and the top of the discharge hood is connected to the first medium inlet.

[0045] Furthermore, a dust removal mechanism is provided between the first medium inlet and the calcining furnace. In this way, the high-temperature flue gas is first treated to remove dust, which can reduce the possibility of the pipes of the indirect heat exchanger being blocked. Moreover, the collected solid materials can be batched with the calcining material for subsequent processing.

[0046] Preferably, the dust removal mechanism includes a cyclone dust collector and a high-temperature dust collector, and the roasting furnace, the cyclone dust collector, the high-temperature dust collector and the first medium inlet are connected in sequence.

[0047] Optionally, the high-temperature dust collector is an existing high-temperature resistant dust collector, such as the high-temperature dust collector described in the prior art, such as CN101559307A and CN110743265B.

[0048] Furthermore, at least one of the inner wall of the first cylinder, the rotating shaft, and the blades is made of a thermally conductive material; preferably, the thermally conductive material includes one or more of magnesium alloy, aluminum alloy, steel, and copper alloy. Thus, the aforementioned components possess good thermal conductivity and heat storage capabilities. During operation, their temperature rises rapidly, allowing the waste battery powder to not only exchange heat with hot air but also undergo multiple and continuous solid-solid interface conduction heating during collisions and contact with these materials. This enhances the heating effect and more effectively promotes the separation of residual electrolytes, binders, and active substances in the waste battery powder. It also promotes the full exposure of the roasting reaction interface and heat transfer interface of the waste battery powder, further optimizing the conveying, pretreatment, and roasting effects.

[0049] Based on the same inventive concept, the present invention also provides: a method for roasting waste battery powder, using the roasting system described above, the roasting method comprising the following steps:

[0050] S1. Start the roasting furnace. At the same time, continuously input air through the second medium inlet and open the second valve to heat the air.

[0051] S2. After the target temperature is reached in the roasting furnace, the waste battery powder to be processed is fed into the gas-solid mixer through the first inlet; at the same time, the first valve is opened so that part of the hot air output from the second medium outlet enters the gas-solid mixer. After preliminary dispersing and mixing, a coarse gas-solid mixture is obtained at the first outlet of the gas-solid mixer.

[0052] Among them, the temperature of the solid material at the first outlet is controlled to be 100-300℃;

[0053] S3. The gas-solid coarse mixture is fed into the disturbance enhancement component, and after further dispersion and mixing, a gas-solid fine mixture is obtained at the second outlet.

[0054] Among them, the temperature of the solid material at the second outlet is controlled to be 200-300℃;

[0055] S4. Input the gas-solid fine mixture into the gas-solid separator, and after gas-solid separation, obtain hot waste battery powder and exhaust gas;

[0056] S5. The hot waste battery powder is fed into the roasting furnace through the feeding mechanism, and at the same time, part of the hot air output from the second medium outlet is fed into the roasting furnace. The waste battery powder releases a large amount of heat energy after roasting with the air. After roasting, roasted material and high-temperature flue gas are obtained.

[0057] The working temperature of the roasting furnace is 500-850℃;

[0058] S6. The high-temperature flue gas is fed into an indirect heat exchanger through the first medium inlet and undergoes indirect heat exchange with the air fed through the second medium inlet. Low-temperature flue gas is obtained at the first medium outlet and hot air is obtained at the second medium outlet.

[0059] S7. Repeat S2-S6 until all waste battery powder to be processed is roasted.

[0060] By using a gas-solid mixture, a disturbance enhancement component, and a temperature gradient setting in the roasting furnace, the preheating, separation, and roasting of the material are carried out in stages according to the direction of travel. Furthermore, by controlling the temperature of the material during pneumatic conveying, the organic matter in the material can be volatilized without producing tar or other sticky substances.

[0061] Optionally, the battery is an alkali metal battery; more specifically, the alkali metal battery includes one or more of lithium batteries and sodium batteries.

[0062] The roasting system of this invention has a simple unit structure and a reasonable overall layout. On the one hand, it can greatly reduce the cost of equipment procurement, operation and maintenance, and has a wide range of raw material applicability, suitable for impurity powders, wet powders, and agglomerated powders. On the other hand, it can fully recover the large amount of heat energy generated during the roasting process. The heat released by the roasting reaction is exchanged into high-temperature hot air through an indirect heat exchanger. Part of the hot air is used for pneumatic conveying of waste battery powder, and the material is preheated and dispersed step by step during the pneumatic conveying process. In the disturbance enhancement section, the waste battery powder is directly and simultaneously heated and granulated. The process involves refining and separating organic matter through volatilization, ensuring thorough preparation for subsequent roasting. This effectively prevents caking of the roasted material and ring formation in the roasting furnace caused by excessively high local temperature differences, optimizing the roasting process. Simultaneously, harmful gases are collected and treated efficiently in a short process, reducing corrosion to the roasting system and contributing to extending the service life of the system and related components. A portion of the high-temperature hot air from the heat exchange is introduced into the roasting furnace for roasting waste battery powder, thereby effectively improving energy utilization and reducing energy consumption, overcoming the shortcomings of existing technologies that can only recover a portion of heat and have low heat utilization rates. Furthermore, and more preferably, the material is sequentially conveyed through multiple air paths, such as horizontal and vertical air paths, ensuring sufficient dispersion of the material entering the gas-solid separator. The conveying process is further enhanced by mechanical and airflow-assisted preheating and dispersion, effectively preventing conveying blockages. This method has low raw material requirements and wide applicability. In addition, physical gas sealing is achieved through the cooperation of a transition bin and a feeding mechanism (especially a screw feeder), enabling gas path isolation with a simple structure.

[0063] Compared with existing technologies, the roasting system of the present invention combines multiple advantages such as high material transport smoothness, high energy utilization rate, low energy consumption, good roasting effect, and green environmental protection through multi-mode material transport and hot air distribution. It has good prospects for industrial application and helps to better realize the industrial roasting treatment of waste battery powder. Attached Figure Description

[0064] Figure 1 This is a simplified structural diagram of the roasting system of Embodiment 1 of the present invention.

[0065] Figure 2 This is a simplified structural diagram of the disturbance enhancement component according to Embodiment 1 of the present invention.

[0066] Figure 3 This is a perspective view of the internal structure of the disturbance enhancement component according to Embodiment 1 of the present invention.

[0067] Figure 4This is a perspective view of the shaft and blades of Embodiment 1 of the present invention.

[0068] Figure 5 This is a simplified structural diagram of the roasting system of Embodiment 2 of the present invention.

[0069] Figure 6 This is a perspective view of the disturbance enhancement component according to Embodiment 2 of the present invention.

[0070] Figure 7 This is a perspective view of the shaft and blades of Embodiment 2 of the present invention.

[0071] Figure 8 This is a cross-sectional view of the rotating shaft in Embodiment 2 of the present invention. Detailed Implementation

[0072] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. For ease of description, the words "upper," "lower," "left," and "right" appearing below only indicate that they are consistent with the upper, lower, left, and right directions of the drawings themselves, and do not limit the structure.

[0073] Example 1

[0074] See Figures 1-4 A calcination system for waste lithium battery powder includes a silo assembly 1, a gas-solid mixer 2.6, a disturbance enhancement component 2.7, a gas-solid separator 2.1, a calcination furnace 3, an indirect heat exchanger 6, and an exhaust gas treatment unit 8.

[0075] The silo assembly 1 includes a silo body 1.1 for temporarily storing waste lithium battery powder, and a first level gauge 1.2 for monitoring the material level is provided in the silo body;

[0076] The gas-solid mixer 2.6 is provided with a first inlet 2.61, an air inlet 2.62, and a first outlet 2.63, as well as a stirring mechanism installed inside the gas-solid mixer; the bottom of the hopper body is connected to the first inlet 2.61 through a fifth valve 1.3 (a rotary sealing valve for convenient quantitative feeding);

[0077] The disturbance enhancement component 2.7 includes a vertically arranged first cylinder 2.71, a rotating shaft 2.72 disposed within the first cylinder 2.71, a second inlet 2.74 and a second outlet 2.75 disposed on the first cylinder 2.71, and a drive mechanism connected to the rotating shaft. The rotating shaft 2.72 extends along the length direction of the first cylinder 2.71, and a plurality of blades 2.73 are provided on the rotating shaft 2.72, which are evenly distributed sequentially along the length direction of the rotating shaft 2.72. The second inlet 2.74 communicates with the first outlet 2.73. The second inlet 2.74 is located on the side wall of one end (lower end) of the first cylinder, and the second outlet 2.75 is located on the side wall of the other end (upper end) of the first cylinder.

[0078] The inlet of the gas-solid separator 2.1 is connected to the second outlet 2.75. The exhaust port of the gas-solid separator 2.1 is equipped with a first fan 2.2 (high-pressure fan). The outlet of the first fan 2.2 is connected to the exhaust gas treatment unit 8 to treat the air after heat exchange. The gas-solid separator 2.1 is a bag filter dust collector. Thus, the gas-solid mixer 2.6, the disturbance enhancement component 2.7, the gas-solid separator 2.1 and related pipelines constitute a pneumatic conveying system 2. While realizing the pneumatic conveying of waste lithium battery powder, it also completes the preheating, refining and organic matter removal of the waste lithium battery powder. The first fan 2.2 provides suction to the pneumatic conveying system 2, so that the waste lithium battery powder and some hot air are drawn into the gas-solid mixer. Under the high-speed centrifugal stirring action of the stirring mechanism, the waste lithium battery powder and hot air are fully mixed and suspended in the hot air. In the gas-solid separator, waste lithium battery powder is separated from air. The waste lithium battery powder enters the transition chamber 2.4, and the resulting gas enters the exhaust gas treatment unit through the first fan 2.2.

[0079] The gas-solid mixer includes a second cylinder, and a stirring mechanism is disposed inside the second cylinder. The second cylinder has an inlet end and an outlet end distributed along the axial direction. A first inlet, an air inlet, and a first outlet are all disposed on the second cylinder. The first inlet is located at the inlet end of the second cylinder, the air inlet is located at the inlet end of the second cylinder, and the first outlet is located at the outlet end of the second cylinder.

[0080] The stirring mechanism of the gas-solid mixer includes multiple dispersing blades arranged along the axial direction.

[0081] The feed inlet of the roasting furnace 3 is connected to the discharge outlet of the gas-solid separator 2.1 through the feeding mechanism 3.1;

[0082] The indirect heat exchanger 6 has a first medium inlet, a first medium outlet, a second medium inlet, and a second medium outlet. The first medium inlet and the first medium outlet are interconnected, as are the second medium inlet and the second medium outlet. The first medium inlet is connected to the exhaust port of the calcining furnace 3, and the first medium outlet is connected to the exhaust gas treatment unit 8 via a second fan 7. The second medium inlet is equipped with a third fan 6.3, and the second medium outlet is connected to a fourth valve 6.2 (ventilation butterfly valve). The outlet of the fourth valve 6.2 is connected to a first valve 6.5 (ventilation butterfly valve) and a second valve 6.4 (ventilation butterfly valve). The outlet of the first valve 6.5 is connected to the air inlet 2.62 of the gas-solid mixer 2.6, and the outlet of the second valve 6.4 is connected to the air inlet of the calcining furnace 3.

[0083] The blade 2.73 includes 3 blades; the 3 blades are evenly distributed around the circumference of the shaft 2.72; the blades of adjacent blades 2.73 are staggered; the blades are inclined around the circumference of the shaft 2.72, such that the angle between the width direction of the blade and the cross section of the first cylinder 2.71 (the section perpendicular to the central axis of the first cylinder) is 45°; the gas-solid mixer 2.6 is a centrifugal stirring mixer.

[0084] The inner wall of the first cylinder 2.71, the rotating shaft 2.72, and the blades 2.73 are all made of steel. The outer surface of the first cylinder is provided with a layer of thermal insulation material.

[0085] It also includes a transition chamber 2.4 connected to the outlet of the gas-solid separator 2.1. A second level gauge 2.3 is installed in the transition chamber 2.4 to monitor the material level in the transition chamber, ensuring that the transition chamber 2.4 and the material form a good seal to prevent gas containing volatile organic compounds and separated substances from penetrating into the roasting furnace, and also to prevent gas in the roasting furnace from back-permeating into the gas-solid separator. The bottom of the transition chamber 2.4 is provided with a third outlet, which is connected to the inlet of the feeding mechanism 3.1 through a fourth valve 2.5 (rotary sealing valve). The feeding mechanism 3.1 is a screw feeding mechanism.

[0086] The roasting furnace 3 is a rotary heating furnace; the rotary heating furnace has a rotary cylinder assembly 3.2 and a discharge hood 3.4 rotatably connected to the discharge end of the rotary cylinder assembly 3.2. The feeding mechanism 3.1 and the second valve 6.4 are both connected to the feed end of the rotary cylinder assembly 3.2. The bottom of the discharge hood 3.4 is provided with a roasting material outlet, which is connected to a cooling device 3.6 through a sixth valve (rotary sealing valve) 3.5 to cool the roasting material. The top of the discharge hood 3.4 is connected to the first medium inlet. The rotary cylinder assembly 3.2 has a heating module 3.3 to heat the material inside. Waste lithium battery powder and hot air are further heated in the roasting furnace, undergoing a roasting reaction and releasing a large amount of heat. Since the waste lithium battery powder and air have been heated to a certain high temperature before entering the rotary drum assembly, compared with the waste lithium battery powder and air at room temperature in the rotary drum assembly, it only needs to absorb a small amount of heat to quickly reach the roasting reaction temperature, which can greatly reduce the heating time and heating energy consumption. Moreover, the waste lithium battery powder has been fully dispersed and organic matter removed during the pneumatic conveying process, which makes the roasting reaction more efficient, complete and smooth.

[0087] A dust removal mechanism is provided between the first medium inlet and the exhaust port of the roasting furnace 3 to remove dust particles contained in the high-temperature flue gas. The dust removal mechanism includes a cyclone dust collector 4 and a high-temperature dust collector 5, and the exhaust port of the roasting furnace 3, the cyclone dust collector 4, the high-temperature dust collector 5, and the first medium inlet are connected in sequence. The discharge ports of the cyclone dust collector 4 and the high-temperature dust collector 5 are both connected to the cooling device 3.6.

[0088] Example 2

[0089] Repeat Example 1, with the main difference being: see Figures 5-8 The second medium outlet is connected to a first valve 6.5 (ventilation butterfly valve), a second valve 6.4 (ventilation butterfly valve), and a third valve 6.6 (ventilation butterfly valve). The rotating shaft 2.72 is a hollow tube. The outlet of the third valve 6.6 is rotatably connected to one end of the rotating shaft 2.72 via a rotary joint, and the other end of the rotating shaft 2.72 is sealed. The blade has a cavity 2.732, which is connected to the rotating shaft 2.72. Multiple air holes 2.731 communicating with the cavity are provided on the blade. Air holes are provided on both the upper and lower surfaces of the blade. Optionally, as another embodiment, air holes are provided on both the upper surface and the end face of the blade.

[0090] The roasting method using the roasting system described in Example 2 includes the following steps:

[0091] S1. Start the roasting furnace. At the same time, continuously input air through the second medium inlet and open the second valve 6.4 to heat the air.

[0092] S2. After the target temperature is reached in the calcination furnace, the lithium iron phosphate battery black powder to be processed is continuously fed into the gas-solid mixer 2.6 through the first inlet 2.61; at the same time, the first valve 6.5 is opened so that part of the hot air output from the second medium outlet enters the gas-solid mixer 2.6. After preliminary dispersing and mixing, a gas-solid coarse mixture is obtained at the first outlet 2.63 of the gas-solid mixer 2.6.

[0093] The temperature of the solid material at the first outlet is 150℃;

[0094] S3. Input the gas-solid coarse mixture into the disturbance enhancement component 2.7, and at the same time open the third valve 6.6 so that part of the hot air output from the second medium outlet enters the disturbance enhancement component 2.7. After the material is further dispersed and mixed, a gas-solid fine mixture is obtained at the second outlet 2.75.

[0095] The temperature of the solid material at the second outlet is 250℃;

[0096] S4. Input the gas-solid fine mixture into the gas-solid separator 2.1. After gas-solid separation, obtain hot waste lithium battery powder and tail gas.

[0097] S5. The hot waste lithium battery powder is fed into the roasting furnace through the feeding mechanism. At the same time, part of the hot air output from the second medium outlet is fed into the roasting furnace. After air roasting, roasted material and high-temperature flue gas are obtained.

[0098] The working temperature of the roasting furnace is 650℃;

[0099] S6. The high-temperature flue gas is fed into the indirect heat exchanger 6 through the first medium inlet and undergoes indirect heat exchange with the air fed through the second medium inlet. Low-temperature flue gas is obtained at the first medium outlet and hot air is obtained at the second medium outlet.

[0100] S7. Repeat S2-S6 until all waste lithium battery powder to be processed is roasted.

[0101] In S2, in the gas-solid mixer 2.6, the volume ratio of the input amount of the waste lithium battery powder to be processed to the input amount of air is 10%; in S5, the calcination time is 60 min.

[0102] Example 3

[0103] The example 1 is repeated, with the main difference being that the length of the multiple dispersing blades decreases first and then increases along the material transport direction in the gas-solid mixer, and the density of the multiple dispersing blades increases sequentially along the material transport direction in the gas-solid mixer.

[0104] Example 4

[0105] Example 2 is repeated, with the main difference being that the number of pores on the blades of each blade 2.73 gradually increases from the second inlet 2.74 to the second outlet 2.75.

[0106] Example 5

[0107] The embodiment 1 is repeated, with the main difference being that the first outlet is located higher than the first inlet, and the angle between the axis of the second cylinder and the horizontal plane is 15°; while the angle between the axis of the first cylinder and the horizontal plane is 75°.

[0108] Example 6

[0109] The same example as Example 1 is repeated, with the main difference being that the number of disturbance enhancement components is 3; the gas-solid mixer, each disturbance enhancement component, and the gas-solid separator are connected in series.

[0110] Example 7

[0111] The same example as Example 1 is repeated, except that the number of disturbance enhancement components is 3, and each disturbance enhancement component is connected in parallel between the gas-solid mixer and the gas-solid separator.

[0112] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A roasting system for waste battery powder, characterized in that, include: A gas-solid mixer (2.6) is provided with a first inlet (2.61), an air inlet (2.62), and a first outlet (2.63); at least one disturbance enhancement component (2.7), the disturbance enhancement component (2.7) includes a first cylinder (2.71), a rotating shaft (2.72) disposed within the first cylinder (2.71), a second inlet (2.74) and a second outlet (2.75) disposed on the first cylinder (2.71), the rotating shaft (2.72) extends along the length direction of the first cylinder (2.71), and a plurality of blades (2.73) are provided on the rotating shaft (2.72), the plurality of blades (2.73) being sequentially distributed along the length direction of the rotating shaft (2.72); the second inlet (2.74) is connected to the first outlet (2.63); Gas-solid separator (2.1), the inlet of which is connected to the second outlet (2.75); calcining furnace (3), the feed inlet of which is connected to the discharge outlet of the gas-solid separator (2.1) via a feeding mechanism (3.1); as well as An indirect heat exchanger (6) has a first medium inlet, a first medium outlet, a second medium inlet, and a second medium outlet. The first medium inlet and the first medium outlet are interconnected, as are the second medium inlet and the second medium outlet. The first medium inlet is connected to the exhaust port of the calcining furnace (3), and the second medium outlet is connected to a first valve (6.5) and a second valve (6.4). The outlet of the first valve (6.5) is connected to the air inlet (2.62) of the gas-solid mixer (2.6), and the outlet of the second valve (6.4) is connected to the air inlet of the calcining furnace (3).

2. The calcination system according to claim 1, characterized in that, The second inlet is located at or near one end of the first cylinder, and the second outlet is located at or near the other end of the first cylinder; preferably, the angle between the axial direction of the first cylinder and the horizontal plane is 45-90°, more preferably 60-90°, and even more preferably 75-90°; more preferably, the location of the second outlet is higher than the location of the second inlet; Preferably, the gas-solid mixer (2.6) is a centrifugal stirring mixer; And / or, The gas-solid mixer includes a second cylinder with an inlet end and an outlet end distributed along the axial direction. A first inlet, an air inlet, and a first outlet are all disposed on the second cylinder. The first inlet is located at or near the inlet end of the second cylinder, the air inlet is located at or near the inlet end of the second cylinder, and the first outlet is located at or near the outlet end of the second cylinder. Preferably, the angle between the axial direction of the second cylinder and the horizontal plane is 0-30°, more preferably 5-25°, and even more preferably 10-20°. More preferably, the first outlet is located higher than the first inlet. And / or, The gas-solid mixer includes a second cylinder, and a stirring mechanism is provided inside the second cylinder. The stirring mechanism includes a plurality of dispersing blades arranged along the axial direction of the stirring mechanism. Preferably, the length of the plurality of dispersing blades decreases first and then increases along the material conveying direction inside the gas-solid mixer. More preferably, the density of the plurality of dispersing blades along the axial direction of the stirring mechanism increases sequentially along the material conveying direction inside the gas-solid mixer.

3. The calcination system according to claim 1, characterized in that, The blade (2.73) comprises at least two blades, preferably three blades; the at least two blades are evenly distributed circumferentially along the axis of rotation (2.72); Preferably, the blades of axially adjacent blades (2.73) are staggered. Preferably, the blade is inclined circumferentially along the axis of rotation (2.72), such that the angle between the width direction of the blade and the cross section of the first cylinder (2.71) is 30-60°. Preferably, the disturbance enhancement component (2.7) further includes a drive mechanism connected to the rotating shaft drive.

4. The calcination system according to claim 1, characterized in that, The second medium outlet is connected to a first valve (6.5), a second valve (6.4), and a third valve (6.6). The rotating shaft (2.72) is a hollow tube. The outlet of the third valve (6.6) is rotatably connected to one end of the rotating shaft (2.72), and the other end of the rotating shaft (2.72) is sealed. The blade has a cavity that is connected to the rotating shaft (2.72), and multiple air holes that communicate with the cavity are opened on the blade. Preferably, from the second inlet (2.74) to the second outlet (2.75), the number of pores on the blades of each blade (2.73) gradually increases.

5. The calcination system according to any one of claims 1-4, characterized in that, The number of disturbance enhancement components (2.7) is more than two; the gas-solid mixer (2.6), each disturbance enhancement component (2.7), and the gas-solid separator (2.1) are connected in series, or each disturbance enhancement component (2.7) is connected in parallel between the gas-solid mixer (2.6) and the gas-solid separator (2.1).

6. The calcination system according to any one of claims 1-4, characterized in that, It also includes an exhaust gas treatment unit (8) connected to the exhaust port of the gas-solid separator (2.1). Preferably, a first fan (2.7) is provided between the exhaust port of the gas-solid separator (2.1) and the exhaust gas treatment unit (8). Preferably, it further includes a transition chamber (2.4) connected to the outlet of the gas-solid separator (2.1), the bottom of the transition chamber (2.4) is provided with a third outlet, the third outlet is connected to the inlet of the feeding mechanism (3.1) through a fourth valve (2.5); preferably, the feeding mechanism (3.1) is a screw feeding mechanism.

7. The calcination system according to any one of claims 1-4, characterized in that, The roasting furnace (3) is a rotary heating furnace; Preferably, the rotary heating furnace includes a rotary cylinder assembly (3.2) and a discharge hood (3.4) rotatably connected to the discharge end of the rotary cylinder assembly (3.2), and the feeding mechanism (3.1) and the second valve (6.4) are both connected to the feed end of the rotary cylinder assembly (3.2); The bottom of the discharge hood (3.4) is provided with a roasting material outlet, and the top of the discharge hood (3.4) is connected to the first medium inlet.

8. The calcination system according to any one of claims 1-3, characterized in that, A dust removal mechanism is provided between the first medium inlet and the roasting furnace (3); Preferably, the dust removal mechanism includes a cyclone dust collector (4) and a high-temperature dust collector (5), and the roasting furnace (3), the cyclone dust collector (4), the high-temperature dust collector (5) and the first medium inlet are connected in sequence.

9. The calcination system according to any one of claims 1-4, characterized in that, At least one of the inner wall of the first cylinder (2.71), the rotating shaft (2.72), and the blade (2.73) is made of a thermally conductive material; preferably, the thermally conductive material includes one or more of magnesium alloy, aluminum alloy, steel, and copper alloy.

10. A method for calcining waste battery powder, characterized in that, The roasting method is carried out using the roasting system as described in any one of claims 1-9, and includes the following steps: S1. Start the roasting furnace. At the same time, continuously input air through the second medium inlet and open the second valve (6.4) to heat the air. S2. After the target temperature is reached in the roasting furnace, the waste battery powder to be processed is fed into the gas-solid mixer (2.6) through the first inlet (2.61); at the same time, the first valve (6.5) is opened so that part of the hot air output from the second medium outlet enters the gas-solid mixer (2.6). After preliminary dispersing and mixing, a coarse gas-solid mixture is obtained at the first outlet (2.63) of the gas-solid mixer (2.6). S3. The gas-solid coarse mixture is fed into the disturbance enhancement component (2.7), and after further dispersing and mixing, a gas-solid fine mixture is obtained at the second outlet (2.75). S4. The gas-solid fine mixture is fed into the gas-solid separator (2.1). After gas-solid separation, hot waste battery powder and tail gas are obtained. S5. The hot waste battery powder is fed into the roasting furnace through the feeding mechanism, and at the same time, part of the hot air output from the second medium outlet is fed into the roasting furnace. After roasting, roasted material and high-temperature flue gas are obtained. S6. The high-temperature flue gas is fed into the indirect heat exchanger (6) through the first medium inlet and exchanged indirectly with the air fed through the second medium inlet. Low-temperature flue gas is obtained at the first medium outlet and hot air is obtained at the second medium outlet. S7. Repeat S2-S6 until all waste battery powder to be processed is roasted.

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