New process for implementing granulation and pre-carbonization integrated production by using rotary kiln

Abstract

Disclosed in the present invention is a new process for implementing granulation and pre-carbonization integrated production by using a rotary kiln. The rotary kiln comprises a granulation-section rotary kiln and a pre-carbonization-section rotary kiln. The process comprises the following steps: subjecting a negative electrode raw material to an arch-breaking pre-treatment by means of a feeding surge bin, then allowing same to enter a shaftless feeding screw, directly feeding same into the granulation-section rotary kiln, uniformly raising the temperature of a granulation section, and performing granulation under the action of a granulation-section lifter bar; feeding the material into the pre-carbonization section rotary kiln, maintaining the temperature of a pre-carbonization section, and performing pre-carbonization under the action of a pre-carbonization-section lifter bar; and cooling the high-temperature material having a temperature of 850-880°C after granulation and pre-carbonization to 480-520°C by means of a water cooling jacket at a discharge outlet of a sedimentation discharge cover, and discharging same to a cooling device of another system. In the present invention, the granulation and pre-carbonization processes by means of one rotary kiln are truly achieved, the occupied space is reduced, and the automation degree and the production efficiency are improved.

Description

A new production process that integrates granulation and pre-carbonization using a rotary kiln Technical Field

[0001] This invention relates to the field of anode material production technology, specifically to a new production process that integrates granulation and pre-carbonization using a rotary kiln. Background Technology

[0002] Anode materials are the most mature and widely used material among the four major materials for new energy vehicle power batteries, and they are also one of the main factors affecting the energy density of lithium batteries, accounting for 10% to 15% of the cost. An ideal lithium-ion battery should possess properties such as low potential, structural stability, small potential variation, good reversibility of lithium-ion insertion / extraction, good conductivity, good interface stability, and low interface AC impedance to meet the requirements of higher energy density and charge / discharge capabilities. The most crucial steps in manufacturing lithium battery anode materials are granulation and carbonization processes. Currently, traditional granulation and pre-carbonization equipment includes roller kilns or tunnel kilns, while newly developed equipment is rotary kilns.

[0003] Currently, the granulation and pre-carbonization processes of mainstream anode materials must be carried out separately. The material is granulated at 650℃ and then cooled to room temperature. Then, it is heated to 1000℃ in a different furnace to complete pre-carbonization, followed by further cooling. Traditional granulation and pre-carbonization processes result in significant heat loss and high energy consumption. Traditional reactors are still used in these critical processes. In these reactors, the vessel body remains stationary while an internal stirring device agitates the material, and external electric heating is used to complete the stirring and heating process—the granulation process. After cooling, the material enters a roller kiln or tunnel kiln to complete the pre-carbonization process. Traditional equipment makes granulation and carbonization separate processes, resulting in a complex process and significant resource waste. Furthermore, both granulation and pre-carbonization are done intermittently: one batch of material is loaded, heated to 650℃, granulated, and then discharged before the next batch is added. This intermittent feeding and discharging process has disadvantages such as high energy consumption, low production capacity, and significant energy waste. Existing theoretical continuous granulation / pre-carbonization methods only provide a direction without specifying crucial firing process parameters and design parameters. Therefore, they cannot truly achieve integrated continuous granulation / pre-carbonization. For example, utility model patent CN218872122U, an integrated production line for granulation and pre-carbonization of anode materials, uses two rotary kilns to achieve granulation and pre-carbonization functions respectively. Invention patent CN115367746A, a continuous granulation / pre-carbonization method and preparation method for graphite anode materials, uses one rotary kiln to achieve granulation and pre-carbonization functions. It only proposes a process route without specifying the residence time, material filling rate, rotary kiln tilt angle, or the specific form of the lifting plate; it only provides a theoretical possibility. Besides the methods disclosed in these patents, current anode material granulation and pre-carbonization cannot be integrated. A production process combining two independent granulation and independent pre-carbonization steps is required to achieve integrated granulation and pre-carbonization production.

[0004] Therefore, in order to solve the above problems, this invention discloses a new production process that uses a rotary kiln to achieve integrated granulation and pre-carbonization, so as to realize continuous granulation / pre-carbonization integration, which obviously has practical significance.

[0005] Summary of the Invention

[0006] The purpose of this invention is to provide a new production process that integrates granulation and pre-carbonization using a rotary kiln, so as to achieve continuous granulation / pre-carbonization integration.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A new production process that integrates granulation and precarbonization using a rotary kiln, wherein the rotary kiln includes a granulation section rotary kiln and a precarbonization section rotary kiln;

[0009] The front end of the rotary kiln in the granulation section is equipped with a feed hood combination seal, which is welded to the shaftless feed screw. The shaftless feed screw is integrally connected to the feed buffer bin. The rear end of the rotary kiln in the pre-carbonization section is equipped with a discharge hood combination seal, which is welded to the settling discharge hood. The settling discharge hood is fastened to the water-cooled jacket at the discharge port.

[0010] The burner system is located directly below the rotary kiln in the granulation section and the rotary kiln in the pre-carbonization section, and is assembled and connected to the furnace of the rotary kiln in the granulation section and the rotary kiln in the pre-carbonization section.

[0011] The three-stage support for the rotary kiln is set at the kiln head cylinder of the granulation section rotary kiln, at the cylinder between the granulation section rotary kiln and the pre-carbonization section rotary kiln, and at the kiln tail cylinder of the pre-carbonization section rotary kiln.

[0012] The rotary kiln motor is configured as a conveying device for the rotary kiln in the granulation section and the rotary kiln in the precarbonization section. The flue gas duct of the granulation section is connected to the furnace of the rotary kiln in the granulation section. The flue gas recycling duct from the precarbonization section is a connecting duct between the furnaces of the rotary kiln in the granulation section and the rotary kiln in the precarbonization section. The lifting plates of the granulation section are installed inside the cylinder of the rotary kiln in the granulation section. The lifting plates of the precarbonization section are installed inside the cylinder of the rotary kiln in the precarbonization section. An integrated adjustable angle frame is installed below the rotary kiln.

[0013] The process specifically includes the following steps:

[0014] (1) After the negative electrode raw material is pretreated by breaking the arch in the feed buffer bin, it is directly fed into the rotary kiln of the granulation section by the shaftless feed screw. After the temperature rises uniformly in the granulation section and the residence time is 2 to 2.5 hours, the material is granulated under the action of the lifting plate in the granulation section.

[0015] (2) The material is fed into the rotary kiln of the pre-carbonization section, and after the temperature is maintained in the pre-carbonization section and the residence time is 2 to 2.5 hours, the material is pre-carbonized under the action of the lifting plates in the pre-carbonization section.

[0016] (3) After granulation in step (1) and pre-carbonization in step (2), the high-temperature material at 850-880°C is cooled to 480-520°C by the water-cooled jacket of the discharge port of the settling discharge hood and then discharged to other system cooling equipment.

[0017] Preferably, the granulation section is divided into four heating zones, each with independent temperature control. Each heating zone is 2.5m long and is separated from the others, with separate exhaust. The maximum operating temperature outside the drum in the preheating zone of the granulation section is 800℃, and the material residence time is 1-2 hours.

[0018] The material temperature in one of the four heating zones is 300-400℃ in reality, with a maximum designed temperature of 800℃. The total power is 400KW, and there are 2 burners in each zone.

[0019] Material temperature in Zone 2: actual 400-500℃, designed maximum 800℃, total power 400KW, 2 burners per zone;

[0020] Material temperature in three zones: actual 500-600℃, designed maximum 800℃, total power 400KW, 2 burners per zone;

[0021] The material temperature in the four zones is 600-700℃ in reality, with a maximum designed temperature of 800℃. The total power is 400KW, and there are two burners in each zone.

[0022] Preferably, the pre-carbonization section is divided into four heating zones, each with its own temperature control. The zones are not separated and share a common exhaust port. The maximum operating temperature outside the drum in the pre-carbonization zone is 1150°C, and the material residence time is 1 to 2 hours.

[0023] The material temperature in one of the four heating zones is: actual 950-1050℃, designed maximum 1150℃, total power 550KW, and two burners per zone.

[0024] Material temperature in Zone 2: actual 950-1050℃, designed maximum 1150℃, total power 550KW, 2 burners per zone;

[0025] Three-zone material temperature: actual 950~1050℃, designed maximum 1150℃, total power 550KW, 2 burners per zone;

[0026] Material temperature in four zones: actual 950-1050℃, designed maximum 1150℃, total power 550KW, two burners per zone.

[0027] Preferably, the optimal tilt angle of the rotary kiln is 0.4 to 1°, the rotation speed of the rotary kiln is controlled at 0.5 to 5 r / min, and the material filling rate of the rotary kiln is 6 to 7%.

[0028] Preferably, the feed buffer chamber is equipped with a nitrogen inlet and an arch-breaking agitator, which can isolate air and prevent large pieces of material from getting stuck in the shaftless feed screw.

[0029] Preferably, the shaftless feeding screw is equipped with nitrogen positive pressure protection and an extended length, which can isolate air and prevent material jamming. The extended length allows the raw material to be directly fed into the heating zone, which greatly reduces the length of the cylinder and thus reduces the cost.

[0030] Preferably, the feed hood combined seal is configured with a combination of end face seal, nitrogen labyrinth seal, and packing seal, which can achieve near-zero leakage between the dynamic and static rings, resulting in a better workshop environment.

[0031] Preferably, the discharge hood combination seal is configured with a combination of end face seal + nitrogen labyrinth seal + packing seal, which can achieve near-zero leakage between the dynamic and static rings, thus improving the workshop environment.

[0032] Preferably, the settling discharge hood is equipped with a detachable collision guide plate inside. The settling discharge hood can realize the function of recycling materials and reduce gas entrainment. The guide plate is detachable, which is convenient for maintenance and cleaning.

[0033] Preferably, the discharge port water-cooled jacket is equipped with circulating water inlet and outlet, which can cool the high-temperature material at 850°C to about 500°C, avoiding high-temperature damage to the lower spiral and compensator.

[0034] Preferably, the burner system uses a low-NOx, supersonic stirring burner, which meets the temperature requirements of the granulation section and the high-temperature section, and also ensures the generation of thermal nitrogen oxides. By using a supersonic stirring burner, the flue gas in the furnace can be mixed more evenly and the heat radiation can be more complete.

[0035] Preferably, the rotary kiln three-stage support has three stages, which are set according to the length, temperature and intensity of the rotary kiln.

[0036] Preferably, the granulation section lifting plate is inclined at an angle of 68-72°, the height of the lifting plate is 2 / 3 of the material height, 12 lifting plates are evenly distributed around the circumference, the lifting plate width is 160mm, the length is 250mm, the spacing is 125mm, and the arrangement is staggered to fully realize uniform contact between the material and the lifting plate, increase the probability of material spheroidization, and thus realize the granulation function; more preferably, the granulation section lifting plate is inclined at an angle of 70°.

[0037] Preferably, the pre-carbonization section lifting plate is not tilted, the height of the lifting plate is 1 / 3 of the material height, 12 lifting plates are evenly distributed around the plate, the lifting plate width is 160mm, the length is 250mm, the spacing is 125mm, and the arrangement is staggered to fully realize the uniform contact between the material and the lifting plate, continuously stir the material and transfer heat evenly, and better realize the pre-carbonization function.

[0038] Preferably, the integrated adjustable angle frame can adjust the tilt angle of the rotary kiln to meet the optimal tilt angle conditions.

[0039] Preferably, the rotary kiln motor can achieve variable frequency speed regulation within the range of 0.5 to 5 r / min to meet the speed requirements of granulation pre-carbonization.

[0040] Preferably, the exhaust pipe of the granulation section can lead the flue gas from the granulation section out of the rotary kiln.

[0041] Preferably, the pre-carbonized granulation flue gas recycling pipeline can lead the pre-carbonized 1050°C high-temperature flue gas to the granulation section for heat energy recovery and utilization.

[0042] The "125mm spacing" mentioned above refers to the division along the axial direction of the cylinder. The main purpose is to avoid the lifting plates being continuous along the axial direction of the cylinder. Continuous plates may expand and deform at high temperatures. Intermittent plates can not only absorb thermal expansion, but also allow materials to flow through this interval, increasing the chances of material heat exchange and contact.

[0043] The working principle of this invention is as follows: Utilizing the rotary kiln's specific rotation speed and uniform thermal conductivity, the negative electrode raw material undergoes anaerobic pyrolysis under a nitrogen-filled atmosphere to remove volatiles, granulate, and carbonize. Specifically, in the granulation zone, specific lifting plates are set up, and the residence time and heating temperature (i.e., a uniform temperature rise of 300-650℃ for about 2 hours) are met to achieve the granulation of the negative electrode material. In the pre-carbonization zone, specific lifting plates are set up, and the residence time and heating temperature (i.e., a maintenance temperature of 1050℃ for about 2 hours) are met to achieve the pre-carbonization process of the negative electrode material after granulation.

[0044] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0045] 1. This invention truly realizes the granulation and pre-carbonization process in a single rotary kiln; and the combined sealing of the feed and discharge hoods of this invention, with the combination of end face sealing, nitrogen labyrinth sealing, and packing, can achieve near-zero leakage between the dynamic and static rings.

[0046] 2. The rotary kiln of the granulation section of the present invention is set with sufficient length to meet the residence time requirements. The granulation section is divided into four heating zones, each with independent temperature control, to meet the temperature rise requirements for granulation.

[0047] 3. The settling discharge hood of the present invention raises the height of the discharge hood and is equipped with a detachable collision guide plate inside. The discharge hood can achieve a certain material recovery function and reduce gas entrainment. The guide plate is detachable, which is convenient for maintenance and cleaning.

[0048] 4. The discharge port water-cooled jacket of the present invention is equipped with circulating water inlet and outlet, which can cool high-temperature materials at 850°C to about 500°C, thus avoiding high-temperature damage to the lower spiral and compensator.

[0049] 5. This invention features an integrated adjustable angle frame, which can adjust the tilt angle of the rotary kiln to meet the optimal tilt angle conditions. Different materials typically have different angles of repose, making it difficult to adjust a fixed-angle rotary kiln to a suitable speed to meet product requirements. The adjustable angle frame, however, perfectly solves this problem by adjusting the tilt angle of the rotary kiln.

[0050] 6. The granulation section of this invention features a lifting plate that ensures uniform contact between the material and the lifting plate, increasing the probability of the material forming pellets and thus achieving the granulation function.

[0051] 7. The setting of the lifting plate in the pre-carbonization section of this invention fully realizes the uniform contact between the material and the lifting plate, continuously stirs the material and makes the heat transfer uniform, thus better realizing the pre-carbonization function.

[0052] 8. It saves more than 50% of space, more than 70% of investment costs, more than 60% of operating costs, has a higher degree of automation, and increases production efficiency by 50%. Attached Figure Description

[0053] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0054] Figure 1 is a schematic diagram of the rotary kiln in Embodiment 1 of the present invention;

[0055] Figure 2 is a top view of the rotary kiln in Embodiment 1 of the present invention;

[0056] Figure 3 is a schematic diagram of the cylindrical lifting plate arrangement in Embodiment 1 of the present invention;

[0057] The components include: 1. Feed buffer bin; 2. Shaftless feed screw; 3. Feed hood combination seal; 4. Rotary kiln for granulation section; 5. Rotary kiln for pre-carbonization section; 6. Discharge hood combination seal; 7. Settling discharge hood; 8. Water-cooled jacket for discharge port; 9. Burner system; 10. Three-stage support for rotary kiln; 11. Integrated adjustable angle frame; 12. Rotary kiln motor; 13. Flue gas duct for granulation section; 14. Flue gas reuse duct for pre-carbonization and granulation; 15. Lifting plate for granulation section; 16. Lifting plate for pre-carbonization section. The left-hand attached figure in Figure 3 shows the preheating section of the lifting plate in the cylinder, and the right-hand attached figure in Figure 3 shows the high-temperature section of the lifting plate in the cylinder. The arrows in Figure 3 indicate the rotation direction of the cylinder (viewed from the discharge end to the feed end). Detailed Implementation

[0058] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0062] Example 1

[0063] Referring to Figures 1, 2 and 3, the present invention provides a new process for integrated production of granulation and pre-carbonization using a rotary kiln, wherein the rotary kiln includes a granulation section rotary kiln 4 and a pre-carbonization section rotary kiln 5.

[0064] The front end of the rotary kiln 4 in the granulation section is equipped with a feed hood combination seal 3, which is welded to the shaftless feed screw 2. The shaftless feed screw 2 is integrally connected to the feed buffer chamber 1. The rear end of the rotary kiln 5 in the pre-carbonization section is equipped with a discharge hood combination seal 6, which is welded to the settling discharge hood 7. The settling discharge hood 7 is fastened to the discharge port water-cooled jacket 8.

[0065] The burner system 9 is located directly below the rotary kiln 4 in the granulation section and the rotary kiln 5 in the pre-carbonization section, and is assembled and connected to the furnace of the rotary kiln 4 in the granulation section and the rotary kiln 5 in the pre-carbonization section.

[0066] The three-stage support 10 of the rotary kiln is set at the kiln head cylinder of the granulation section rotary kiln 4, at the cylinder between the granulation section rotary kiln 4 and the pre-carbonization section rotary kiln 5, and at the kiln tail cylinder of the pre-carbonization section rotary kiln 5.

[0067] The rotary kiln motor 12 is configured as a conveying device for the granulation section rotary kiln 4 and the pre-carbonization section rotary kiln 5. The granulation section flue gas pipe 13 is connected to the furnace of the granulation section rotary kiln 4. The pre-carbonization section flue gas recycling pipe 14 is a connecting pipe between the furnaces of the granulation section rotary kiln 4 and the pre-carbonization section rotary kiln 5. The granulation section lifting plate 15 is installed in the cylinder of the granulation section rotary kiln 4. The pre-carbonization section lifting plate 16 is installed in the cylinder of the pre-carbonization section rotary kiln 5. The integrated adjustable angle frame 11 is installed below the rotary kiln.

[0068] The granulation section lifting plate 15 is set with an inclination angle of 70°. The height of the lifting plate is 2 / 3 of the material height. There are 12 evenly distributed lifting plates around the circumference. The lifting plate is 160mm wide, 250mm long, and spaced 125mm apart, staggered.

[0069] The pre-carbonization section lifting plate 16 has no tilt angle. The height of the lifting plate is 1 / 3 of the material height. There are 12 evenly distributed lifting plates around the perimeter. The lifting plate is 160mm wide, 250mm long, and spaced 125mm apart, staggered.

[0070] This embodiment takes a granulation and pre-carbonization anode material production line with an annual output of 10,000 tons as an example. The specific process flow of this embodiment includes the following steps:

[0071] (1) After the negative electrode raw material is pretreated by breaking the arch in the feed buffer bin, it is directly fed into the rotary kiln of the granulation section by the shaftless feed screw. After the temperature rises uniformly at 350-650℃ in the first to fourth zones of the granulation section and the residence time is 2 hours, the material is granulated under the action of the lifting plate in the granulation section.

[0072] (2) The material is fed into the rotary kiln of the pre-carbonization section, and after the temperature is maintained at 1050℃ in the first to fourth zones of the pre-carbonization section and the residence time is 2 hours, the material is pre-carbonized under the action of the lifting plates in the pre-carbonization section.

[0073] (3) After granulation in step (1) and pre-carbonization in step (2), the high-temperature material at 850°C is cooled to 500°C by the water-cooled jacket of the discharge port of the settling discharge hood and then discharged to other system cooling equipment.

[0074] The parameters of the negative electrode raw material are shown in Table 1 below.

[0075] Table 1

[0076] The parameters of the final product generated according to the above process flow are shown in Table 2 below.

[0077] Table 2

[0078] Comparative Example 1

[0079] This comparative example represents the existing technology where the granulation stage and the pre-carbonization stage are separated. High-temperature materials exiting the granulation section of the rotary kiln need to be cooled before entering the pre-carbonization rotary kiln.

[0080] The parameters of the product from this process are shown in Table 3 below.

[0081] Table 3

[0082] Comparison between existing technologies and this invention:

[0083] 1. Comparison of investment costs:

[0084] The existing technology sets up two rotary kilns, each with its own independent feeding and discharging system and sealing device. The space required for each kiln also needs to be set up with its own independent frame and support system. The present invention, however, is an integrated unit, saving a set of feeding and discharging system, sealing device, frame and support device. Based on the above, it can be judged that the investment cost is reduced by more than 70%.

[0085] 2. Comparison of operating costs:

[0086] Current technology consumes 70 Nm³ of natural gas. 3 / t; New technology natural gas consumption 20Nm 3 Based on the above, it can be determined that operating costs are reduced by at least 60%;

[0087] 3. Automated comparison:

[0088] Existing technology requires granulation first, followed by discharge, and then the material enters the pre-carbonization rotary kiln. This operation is more complex and requires the coordination of two processes. The control also needs to take into account the compatibility of the two processes. Based on the above, it can be judged that the new technology has a higher degree of automation and increases production efficiency by 50%.

[0089] In summary, this embodiment truly realizes the granulation and pre-carbonization process using a single rotary kiln; and the combined sealing of the feed and discharge hoods of this invention, with its end face seal + nitrogen labyrinth seal + packing combination seal, can achieve near-zero leakage between the dynamic and static rings.

[0090] The rotary kiln in the granulation section of this embodiment is set with sufficient length to meet the residence time requirements. The granulation section is divided into four heating zones, each with independent temperature control, to meet the temperature rise requirements for granulation.

[0091] The settling discharge hood in this embodiment has an increased height and is equipped with a detachable collision guide plate inside. The discharge hood can achieve a certain material recovery function and reduce gas entrainment. The guide plate is detachable, which is convenient for maintenance and cleaning.

[0092] The discharge port water-cooled jacket of this embodiment is equipped with circulating water inlet and outlet, which can cool the high temperature material of 850°C to about 500°C, avoiding high temperature damage to the lower spiral and compensator.

[0093] This embodiment features an integrated adjustable angle frame, which can adjust the rotary kiln's tilt angle to meet optimal tilt conditions. Different materials typically have different angles of repose, making it difficult to adjust a fixed-angle rotary kiln to a suitable rotation speed to meet product requirements. The adjustable angle frame, however, perfectly solves this problem by adjusting the rotary kiln's tilt angle.

[0094] The setting of the lifting plate in the granulation section of this embodiment fully realizes the uniform contact between the material and the lifting plate, increases the probability of material pelleting, and thus realizes the granulation function;

[0095] The setting of the lifting plate in the pre-carbonization section of this embodiment fully realizes the uniform contact between the material and the lifting plate, continuously stirs the material and makes the heat transfer uniform, thus better realizing the pre-carbonization function.

[0096] It saves more than 50% of space, more than 70% of investment costs, more than 60% of operating costs, has a higher degree of automation, and increases production efficiency by 50%.

[0097] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel production process integrating granulation and pre-carbonization using a rotary kiln, characterized in that, The rotary kiln includes a granulation section rotary kiln and a pre-carbonization section rotary kiln; The front end of the rotary kiln in the granulation section is equipped with a feed hood combination seal, which is welded to the shaftless feed screw. The shaftless feed screw is integrally connected to the feed buffer bin. The rear end of the rotary kiln in the pre-carbonization section is equipped with a discharge hood combination seal, which is welded to the settling discharge hood. The settling discharge hood is fastened to the water-cooled jacket at the discharge port. The burner system is located directly below the rotary kiln in the granulation section and the rotary kiln in the pre-carbonization section, and is assembled and connected to the furnace of the rotary kiln in the granulation section and the rotary kiln in the pre-carbonization section. The rotary kiln has three supports: one at the kiln head of the granulation section rotary kiln, one between the granulation section rotary kiln and the pre-carbonization section rotary kiln, and one at the kiln tail of the pre-carbonization section rotary kiln. The rotary kiln motor is configured as a conveying device for the granulation section rotary kiln and the pre-carbonization section rotary kiln. The flue gas duct of the granulation section is connected to the furnace of the granulation section rotary kiln. The flue gas recycling duct of the pre-carbonization section is a connecting duct between the furnace of the granulation section rotary kiln and the furnace of the pre-carbonization section rotary kiln. The lifting plates of the granulation section are configured inside the cylinder of the granulation section rotary kiln. The lifting plates of the pre-carbonization section are configured inside the cylinder of the pre-carbonization section rotary kiln. An integrated adjustable angle frame is configured below the rotary kiln. The process specifically includes the following steps: (1) After the negative electrode raw material is pretreated by breaking the arch in the feed buffer bin, it is directly fed into the rotary kiln of the granulation section by the shaftless feed screw. After the temperature rises uniformly in the granulation section and the residence time is 2 to 2.5 hours, the material is granulated under the action of the lifting plate in the granulation section. (2) The material is fed into the rotary kiln of the pre-carbonization section, and after the temperature is maintained in the pre-carbonization section and the residence time is 2 to 2.5 hours, the material is pre-carbonized under the action of the lifting plates in the pre-carbonization section. (3) After granulation in step (1) and pre-carbonization in step (2), the high-temperature material at 850-880°C is cooled to 480-520°C by the water-cooled jacket of the discharge port of the settling discharge hood and then discharged to other system cooling equipment.

2. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The granulation section is divided into four heating zones, each with its own temperature control. Each heating zone is 2.5m long and is separated from the others, with separate exhaust. The maximum operating temperature outside the drum in the preheating zone of the granulation section is 800℃, and the material residence time is 1-2 hours. The material temperature in one of the four heating zones is 300-400℃ in reality, with a maximum designed temperature of 800℃. The total power is 400KW, and there are 2 burners in each zone. Material temperature in Zone 2: actual 400-500℃, designed maximum 800℃, total power 400KW, 2 burners per zone; Material temperature in three zones: actual 500-600℃, designed maximum 800℃, total power 400KW, 2 burners per zone; The material temperature in the four zones is 600-700℃ in reality, with a maximum designed temperature of 800℃. The total power is 400KW, and there are two burners in each zone.

3. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The pre-carbonization section is divided into four heating zones, each with its own temperature control. The zones are not separated but share a common exhaust port. The maximum operating temperature outside the drum in the pre-carbonization zone is 1150℃, and the material residence time is 1-2 hours. The material temperature in one of the four heating zones is: actual 950-1050℃, designed maximum 1150℃, total power 550KW, and two burners per zone. Material temperature in Zone 2: actual 950-1050℃, designed maximum 1150℃, total power 550KW, 2 burners per zone; Three-zone material temperature: actual 950~1050℃, designed maximum 1150℃, total power 550KW, 2 burners per zone; Material temperature in four zones: actual 950-1050℃, designed maximum 1150℃, total power 550KW, two burners per zone.

4. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The optimal tilt angle of the rotary kiln is 0.4 to 1°, the rotation speed of the rotary kiln is controlled at 0.5 to 5 r / min, and the material filling rate of the rotary kiln is 6 to 7%.

5. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The feed buffer chamber is equipped with a nitrogen inlet and an arch-breaking agitator; the shaftless feed screw is equipped with nitrogen positive pressure protection and an extended length.

6. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The feed hood combined seal is configured with a combination of end face seal, nitrogen labyrinth seal, and packing seal; the discharge hood combined seal is configured with a combination of end face seal, nitrogen labyrinth seal, and packing seal.

7. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The settling discharge hood is equipped with a detachable collision guide plate inside; the discharge port water-cooled jacket is equipped with circulating water inlet and outlet.

8. The novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The burner system uses low-NOx, supersonic stirring burners; the rotary kiln has a three-stage support with three stages, which are set according to the length, temperature and intensity of the rotary kiln.

9. A novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The granulation section lifting plate is set at an inclination angle of 68-72°, and the height of the lifting plate is 2 / 3 of the material height. Twelve lifting plates are evenly distributed around the circumference of the lifting plate.

10. A novel production process for integrated granulation and pre-carbonization using a rotary kiln as described in claim 1, characterized in that, The pre-carbonization section lifting plate has no tilt angle, and the height of the lifting plate is 1 / 3 of the material height. Twelve lifting plates are evenly distributed around the plate.

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