Rotary kiln for sintering lithium iron phosphate and preparation device

Abstract

The utility model discloses a rotary kiln for sintering lithium iron phosphate and a preparation device, and belongs to the technical field of battery positive electrode materials. The rotary kiln comprises a kiln head, a heating section, a heat preservation section and a kiln tail which are sequentially arranged in the length direction of a rotary kiln body, and the heat preservation section is sleeved with a heat preservation section smoke cavity corresponding to the outer portion of the kiln wall. A plurality of flue gas inlets which are distributed in parallel at intervals and a plurality of flue gas outlets which are distributed at intervals are respectively formed in the bottom and the top of the heat preservation section flue gas cavity; the flue gas inlet and the flue gas outlet are staggered in the axis direction of the heat preservation section flue gas cavity; and the flue gas inlet is used for introducing high-temperature flue gas. According to the scheme, a heat source used by the heat preservation section flue gas cavity is selected as high-temperature flue gas, and the layout of the flue gas inlet and the flue gas outlet in the heat preservation section flue gas cavity is optimally designed, so that the heating uniformity of the kiln wall of the heat preservation section is effectively improved; and the product performance and uniformity of the prepared lithium iron phosphate are effectively improved.

Description

A rotary kiln and preparation apparatus for lithium iron phosphate sintering Technical Field

[0001] This utility model relates to the field of battery cathode material technology, and more specifically, to a rotary kiln and preparation apparatus for lithium iron phosphate sintering. Background Technology

[0002] Lithium iron phosphate (LiFePO4), as a cathode material for lithium-ion batteries, has a stable crystal structure, good cycle performance, and is widely available. As an energy storage material, it is widely used in the new energy industry, which can effectively slow down the consumption rate of primary energy sources such as oil and coal, and accelerate the achievement of carbon peaking and carbon neutrality.

[0003] The sintering preparation of primary lithium iron phosphate often employs solid-state synthesis, with roller kilns being the main equipment used. However, this production method cannot achieve continuous production of lithium iron phosphate and is a static sintering method. The material is spread flat in a pot for static sintering, which leads to uneven heating and inconsistent sintering degrees between the upper and lower layers, easily causing over-burning and under-burning, resulting in poor product performance and uniformity.

[0004] To improve the quality of virgin lithium iron phosphate (LFP) sintering, rotary kilns are now commonly used instead of roller kilns for LFP sintering. The virgin LFP sintering process requires high temperature uniformity; therefore, the heat source for rotary kilns used in LFP sintering is generally directly from electric heating. For example, Chinese Patent Application No. 2024100931030 discloses a LFP sintering system using an electrically heated atmosphere rotary kiln, including a weighing feeder and a rotary kiln. The exhaust pipe at the kiln head is connected to a wet dust collector, and the rear end of the kiln is connected to an LFP outlet and an inert gas inlet. The kiln cylinder is divided into a heating section, a constant temperature section, and a cooling section connected sequentially. Multiple spray nozzles are provided above the cooling section, which is also connected to a cooling water return outlet. This application utilizes the rotary kiln's rotation and internal structural design to effectively tumble the material, ensuring uniform heating and preventing under-burning and over-burning. It also accelerates the decomposition and reaction of ineffective carbon between lithium iron phosphate particles, with carbon encapsulating on the particle surface in nano-form, significantly enhancing the formation of a carbon conductive network structure. Simultaneously, the use of an inert atmosphere protection and an electric heating system effectively shortens sintering time, improves quality, and reduces energy consumption. However, the rotary kiln in this application uses electric heating, resulting in high electricity costs and high wear and tear on the electric heating components.

[0005] Furthermore, the temperature uniformity of existing gas-fired rotary kilns used in other production processes is generally insufficient to meet the requirements of the sintering process of primary lithium iron phosphate. For example, Chinese Patent Application No. 2024100931030 discloses a dehydration system for lithium-ion battery cathode material precursors, including a calcining rotary kiln. One end of the calcining rotary kiln has an inlet for the lithium-ion battery cathode material precursors, and the other end has an outlet for the lithium-ion battery cathode material precursors. The calcining rotary kiln adopts a combined external and internal heating structure. It includes a heater that heats the kiln wall to achieve external heating, and a hot gas supply device that introduces high-temperature gas into the kiln cavity to achieve internal heating. The hot gas supply device is connected to the air inlet on the calcining rotary kiln. Although the design of the air inlet and outlet positions on the rotary kiln in this application allows for sufficient contact between the high-temperature gas and the lithium-ion battery cathode material precursor within the kiln cavity, the use of multiple heater burners to heat corresponding sections of the outer wall of the rotary kiln separately raises concerns about the uniformity of heating. Furthermore, the process used in this application is a dehydration process, which is fundamentally different from the lithium iron phosphate sintering preparation process and therefore cannot be directly applied. Summary of the Invention

[0006] 1. Technical problems to be solved

[0007] To address the technical challenge of improving temperature uniformity in rotary kilns using gas heating during lithium iron phosphate sintering, this invention provides a rotary kiln and preparation apparatus for lithium iron phosphate sintering. This solution effectively improves the heating uniformity of the rotary kiln by selecting high-temperature flue gas as the heat source for the flue gas chamber in the insulation section and optimizing the relative layout of the flue gas inlet and outlet within the flue gas chamber. This, in turn, enhances the performance and uniformity of the resulting lithium iron phosphate product.

[0008] 2. Technical solutions adopted

[0009] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0010] The first aspect of this utility model provides a rotary kiln for lithium iron phosphate sintering, comprising a kiln head, a heating section, a heat preservation section, and a kiln tail arranged sequentially along the length of the main body of the rotary kiln. The heat preservation section has a flue gas chamber fitted around its outer wall. The bottom and top of the flue gas chamber are provided with multiple parallel and spaced flue gas inlets and multiple spaced flue gas outlets. The flue gas inlets and outlets are staggered along the axial direction of the flue gas chamber. The flue gas inlets are used to introduce high-temperature flue gas.

[0011] Furthermore, the rotary kiln also includes a first air inlet pipe and a first air outlet pipe. The first air inlet pipe includes multiple parallel and spaced-apart air inlet branch pipes and multiple parallel and spaced-apart air outlet branch pipes. The air inlet branch pipes and air outlet branch pipes are respectively arranged to correspond to the flue gas inlet and flue gas outlet in the flue gas chamber of the heat preservation section, and are all arranged perpendicular to the length direction of the rotary kiln body.

[0012] Furthermore, the number of flue gas inlets or outlets in the flue gas chamber of the insulation section is at least three, and the number of flue gas outlets differs from the number of flue gas inlets by one.

[0013] Furthermore, a flue gas chamber is provided on the outside of the kiln wall corresponding to the heating section. The flue gas inlet of the heating section flue gas chamber is connected to the flue gas outlet of the insulation section flue gas chamber, which is used to provide high-temperature flue gas to the heating section flue gas chamber.

[0014] The second aspect of this utility model provides a lithium iron phosphate sintering preparation apparatus, including a feeding mechanism, a discharging mechanism, a flue gas generating mechanism, and the aforementioned rotary kiln, wherein the kiln head is connected to the feeding mechanism; the kiln tail is connected to the discharging mechanism; and the flue gas inlet in the flue gas chamber of the heat preservation section is connected to the flue gas generating mechanism for introducing high-temperature flue gas into the flue gas chamber of the heat preservation section.

[0015] Furthermore, the flue gas generating mechanism includes a gas-fired heated hot air furnace, wherein the high-temperature flue gas outlet in the hot air furnace is connected to the flue gas inlet in the flue gas chamber of the insulation section.

[0016] Furthermore, the flue gas generating mechanism also includes an air heat exchanger, which is used to heat the combustion air with the high-temperature flue gas discharged from the flue gas outlet in the rotary kiln. The air heat exchanger is connected to the hot blast stove and is used to introduce the heated combustion air into the hot blast stove.

[0017] Furthermore, the top of the kiln tail is connected to the volatile matter treatment mechanism.

[0018] Furthermore, the volatile matter treatment mechanism includes a connected high-temperature dust collector and a volatile matter induced draft fan. The high-temperature dust collector is connected to the top of the kiln tail; the volatile matter induced draft fan is connected to the hot blast stove in the flue gas generating mechanism and is used to provide fuel to the hot blast stove.

[0019] Furthermore, the feeding mechanism includes a feeding deoxidation chamber, a feeding buffer chamber, a deoxidation nitrogen channel, and a rotary kiln atmosphere nitrogen channel. The feeding deoxidation chamber, the feeding buffer chamber, and the kiln head are connected in sequence. One side of the feeding deoxidation chamber is provided with a deoxidation nitrogen channel connected to it. The rotary kiln atmosphere nitrogen channel is connected to the kiln head. And / or the discharging mechanism includes a cooling kiln and a cooling kiln atmosphere nitrogen channel. The head of the cooling kiln is connected to the bottom of the kiln tail, and the cooling kiln atmosphere nitrogen channel is connected to the tail of the cooling kiln.

[0020] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0021] (1) By selecting high-temperature flue gas as the heat source for the insulation section, this utility model can effectively reduce the temperature fluctuation of the flue gas in the insulation section flue gas cavity compared to directly setting the combustion chamber in the insulation section flue gas cavity, thereby improving the uniformity of heating the kiln wall of the insulation section. Furthermore, the insulation section flue gas cavity has multiple flue gas inlets and flue gas outlets, which are staggered along the axial direction of the insulation section flue gas cavity, increasing the uniformity of the distribution of high-temperature flue gas in the insulation section flue gas cavity, thereby further improving the temperature uniformity in the insulation section flue gas cavity, and thus improving the product performance and uniformity of the prepared lithium iron phosphate.

[0022] (2) This utility model optimizes the design of the flue gas chamber between the heating section and the heat preservation section. Specifically, the heating section and the heat preservation section are respectively provided with a heating section flue gas chamber and a heat preservation section flue gas chamber. The high temperature flue gas heats the corresponding kiln wall of the heat preservation section in the heat preservation section flue gas chamber, and then enters the interior of the heating section flue gas chamber through the flue gas outlet of the heat preservation section flue gas chamber. This helps to reduce the interference of the corresponding kiln section of the heating section to the corresponding kiln section of the heat preservation section.

[0023] (3) This utility model further optimizes the design of the volatile matter treatment mechanism. Specifically, the top of the kiln tail is connected to the volatile matter treatment mechanism. By setting the volatile matter treatment mechanism at the kiln tail, the temperature at the kiln tail is higher than that at the kiln head, which is more conducive to the discharge of volatile matter and reduces the risk of volatile matter gas condensing, sticking to the walls, and clogging the pipes. Furthermore, the volatile matter passes sequentially through a high-temperature dust collector and a volatile matter induced draft fan into the hot blast stove to provide fuel for the hot blast stove, realizing the reuse of volatile matter and reducing the amount of gas used in the hot blast stove.

[0024] (4) The present invention further optimizes the design of the flue gas outlet in the rotary kiln. Specifically, the flue gas outlet in the rotary kiln heats the combustion air through an air heat exchanger, thereby increasing the temperature of the combustion air used in the hot blast stove, reducing the fuel used in the hot blast stove, and helping to maintain combustion stability. Attached Figure Description

[0025] Figure 1 is a simplified schematic diagram of the lithium iron phosphate sintering preparation apparatus according to an embodiment of this utility model, with material flow direction markings.

[0026] Figure 2 is a simplified structural diagram of the lithium iron phosphate sintering preparation apparatus according to an embodiment of this utility model.

[0027] Label Explanation:

[0028] 1. Rotary kiln body; 101. Kiln head; 102. Heating section; 1021. Heating section flue gas chamber; 103. Insulation section; 1031. Insulation section flue gas chamber; 104. Kiln tail; 105. First air inlet pipe; 106. First air outlet pipe;

[0029] 2. Feeding mechanism; 201. Feeding deoxidation chamber; 202. Feeding buffer chamber; 203. Raw material feed regulating valve; 204. Rotary kiln atmosphere nitrogen channel; 205. Deoxidation nitrogen channel;

[0030] 3. Volatile matter treatment unit; 301. High-temperature dust collector; 302. Volatile matter induced draft fan;

[0031] 4. Discharge mechanism; 401. Cooling kiln; 402. Nitrogen gas passage for cooling kiln; 403. Product discharge rotary valve;

[0032] 5. Flue gas generating mechanism; 501. Air heat exchanger; 502. Smoke exhaust fan; 503. Hot air furnace; 504. Combustion fan. Detailed Implementation

[0033] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0034] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0035] This embodiment provides a rotary kiln for lithium iron phosphate sintering. Referring to Figures 1 and 2, the rotary kiln includes a kiln head 101, a heating section 102, a heat preservation section 103, and a kiln tail 104 arranged sequentially along the length of the rotary kiln body 1. The heat preservation section 103 is fitted with a heat preservation section flue gas chamber 1031 on the outside of the kiln wall. The bottom and top of the heat preservation section flue gas chamber 1031 are respectively provided with multiple parallel and spaced flue gas inlets and multiple spaced flue gas outlets. The flue gas inlets and outlets are staggered along the axial direction of the heat preservation section flue gas chamber 1031. The flue gas inlets are used to introduce high-temperature flue gas.

[0036] By introducing high-temperature flue gas into the flue gas chamber 1031 of the insulation section, compared to directly setting up a combustion chamber in the flue gas chamber 1031, the temperature fluctuation of the flue gas in the insulation section 1031 can be effectively reduced, thereby improving the uniformity of heating the kiln wall of the insulation section 103. The temperature fluctuation of the high-temperature flue gas in the flue gas chamber 1031 is ≤5℃, and its temperature is maintained at around 800℃. Furthermore, the flue gas chamber 1031 of the insulation section has multiple flue gas inlets and outlets, which are staggered along the axial direction of the flue gas chamber 1031, increasing the uniformity of the distribution of high-temperature flue gas in the flue gas chamber 1031, thereby further improving the temperature uniformity in the flue gas chamber 1031, and thus improving the performance and uniformity of the prepared lithium iron phosphate product.

[0037] Specifically, the rotary kiln includes a first air inlet pipe 105 and a first air outlet pipe 106; the first air inlet pipe 105 includes multiple parallel and spaced-apart air inlet branches, and the first air outlet pipe 106 includes multiple parallel and spaced-apart air outlet branches. The air inlet branches and the air outlet branches are respectively set to correspond to the flue gas inlet and the flue gas outlet in the flue gas chamber 1031 of the heat preservation section, and are all set perpendicular to the length direction of the rotary kiln body 1.

[0038] More specifically, the number of flue gas inlets or outlets in the flue gas chamber 1031 of the insulation section is at least three, with the number of outlets differing from the number of inlets by one. In some specific embodiments, the number of flue gas inlets in the flue gas chamber 1031 is either three or four, with the three and four inlets staggered along the axial direction of the flue gas chamber 1031, meaning that there is one flue gas inlet between any two adjacent inlets along the axial direction of the flue gas chamber 1031. Appropriately increasing the number of flue gas inlets helps to further improve the uniformity of high-temperature flue gas distribution within the flue gas chamber 1031 of the insulation section.

[0039] Preferably, a heating section flue gas chamber 1021 is fitted outside the kiln wall corresponding to the heating section 102. The flue gas inlet of the heating section flue gas chamber 1021 is connected to the flue gas outlet of the insulation section flue gas chamber 1031 to provide high-temperature flue gas to the heating section flue gas chamber 1021. During the lithium iron phosphate sintering process, since the temperature requirement of the heating section 102 is lower than that of the insulation section 103, only one flue gas inlet and one flue gas outlet can be provided in the heating section flue gas chamber 1021. Preferably,

[0040] The flue gas inlet in the heating section flue gas chamber 1021 is located at its top and close to the insulation section flue gas chamber 1031, while the flue gas outlet in the heating section flue gas chamber is located at its bottom and close to the kiln head 101. That is, the flue gas outlet and inlet in the heating section flue gas chamber 1021 are staggered along the direction from the kiln head 101 towards the kiln tail 104. In the rotary kiln body 1, the material moves from the kiln head 101 to the kiln tail 104. The high-temperature flue gas discharged from the insulation section flue gas chamber 1031 enters the flue gas inlet of the heating section flue gas chamber 1021, restricting the main flow direction of the high-temperature gas from the kiln tail 104 to the kiln head 101. This facilitates counter-current inter-wall heat exchange between the material inside the rotary kiln wall and the high-temperature flue gas in the heating section flue gas chamber 1021 and the insulation section flue gas chamber 1031, thus improving heat transfer efficiency.

[0041] This embodiment also provides a lithium iron phosphate sintering preparation apparatus, as shown in Figures 1 and 2, including a feeding mechanism 2, a discharging mechanism 4, a flue gas generating mechanism 5, and a rotary kiln of any of the above embodiments, wherein the kiln head 101 is connected to the feeding mechanism 2 through a pipe; the kiln tail 104 is connected to the discharging mechanism 4 through a pipe; the flue gas inlet in the flue gas chamber 1031 of the heat preservation section is connected to the flue gas generating mechanism 5, for introducing high-temperature flue gas into the flue gas chamber 1031 of the heat preservation section.

[0042] In a preferred embodiment of the flue gas generating mechanism 5, the flue gas generating mechanism 5 includes a gas-fired heated hot air furnace 503, wherein the high-temperature flue gas outlet of the hot air furnace 503 is connected to the flue gas inlet of the flue gas chamber 1031 in the insulation section via a pipeline. The use of a gas-fired heated hot air furnace 503 in the flue gas generating mechanism 5 is less costly than that of electric heating.

[0043] As an extension, the high-temperature flue gas outlet of the hot blast furnace 503 is connected to the corresponding flue gas inlet of the insulation section flue gas chamber 1031 via multiple inlet branches in the first inlet pipe 105.

[0044] In other embodiments, the flue gas outlet in the rotary kiln is the flue gas outlet of the heating section flue gas chamber 1021. The high-temperature flue gas in the insulation section flue gas chamber 1031 flows out through multiple flue gas outlets to multiple outlet branches in the first outlet pipe 106. The multiple outlet branches are converged into a channel through the pipeline and then enter the insulation section flue gas chamber 1031 to perform indirect heat exchange on the kiln wall of the insulation section 103.

[0045] Furthermore, the flue gas generating mechanism 5 also includes an air heat exchanger 501, which is used to heat the combustion air with the high-temperature flue gas discharged from the flue gas outlet in the rotary kiln. The air heat exchanger 501 is connected to the hot blast stove 503 and is used to introduce the heated combustion air into the hot blast stove 503.

[0046] Specifically, the air heat exchanger 501 has a channel for high-temperature flue gas and a channel for combustion air, where fluids exchange heat within the air heat exchanger 501. The inlet of the channel for high-temperature flue gas is connected to the flue gas outlet of the rotary kiln via a pipe, and the outlet is connected to the exhaust fan 502. The heat-exchanged high-temperature flue gas is then sent to the boundary area for treatment by the exhaust fan 502. The inlet of the channel for combustion air is connected to the combustion fan 504, and the outlet is connected to the air inlet channel of the hot blast stove 503.

[0047] As a further preferred embodiment of the lithium iron phosphate sintering preparation apparatus described above, the top of the kiln tail 104 is connected to the volatile matter treatment mechanism 3. By placing the volatile matter treatment mechanism 3 at the kiln tail 104, the temperature of the kiln tail 104 is higher than that of the kiln head 101, which is more conducive to the discharge of volatile matter and reduces the risk of volatile matter gas condensing, sticking to the walls, and clogging the pipes, thereby improving the continuous production operation rate.

[0048] As an extension, the volatile matter treatment mechanism 3 includes a connected high-temperature dust collector 301 and a volatile matter induced draft fan 302. The high-temperature dust collector 301 is connected to the top of the kiln tail 104. The volatile matter induced draft fan 302 is connected to the hot blast stove 503 in the flue gas generating mechanism 5 through a pipeline and is used to provide fuel to the hot blast stove 503.

[0049] By introducing the volatile gas generated in the rotary kiln body 1 into the hot blast stove 503, the volatile gas is burned in the hot blast stove 503 to generate high-temperature gas that heats the rotary kiln body 1, thereby realizing the reuse of volatiles, reducing the gas consumption of the hot blast stove 503, and thus reducing operating costs.

[0050] As a preferred embodiment of the feeding mechanism 2, the feeding mechanism 2 includes a feeding deoxidation chamber 201, a feeding buffer chamber 202, a deoxidation nitrogen channel 205, and a rotary kiln atmosphere nitrogen channel 204. The feeding deoxidation chamber 201, the feeding buffer chamber 202, and the kiln head 101 are connected in sequence. The feeding deoxidation chamber 201 is provided with a deoxidation nitrogen channel 205 connected to it on one side. The rotary kiln atmosphere nitrogen channel 204 is connected to the kiln head 101.

[0051] The roasting raw material enters the feed deoxidation chamber 201, and nitrogen gas from the deoxidation nitrogen channel 205 enters the feed deoxidation chamber 201 to perform fluidized deoxidation on the material, controlling the oxygen entrainment in the raw material to ≤30ppm. The deoxidized material enters the feed buffer chamber 202 for buffering. A raw material feed regulating valve 203 is installed in the pipeline connecting the feed buffer chamber 202 to the kiln head 101 or at the outlet of the feed buffer chamber 202, controlling the uniform and continuous feeding of material to the kiln head 101.

[0052] As a preferred embodiment of the discharge mechanism 4, the discharge mechanism 4 includes a cooling kiln 401 and a nitrogen channel 402 for the cooling kiln atmosphere. The head of the cooling kiln 401 is connected to the bottom of the kiln tail 104, and the nitrogen channel 402 for the cooling kiln atmosphere is connected to the tail of the cooling kiln 401.

[0053] Specifically, the bottom of the kiln tail 104 is provided with a discharge port, which is connected to the head of the cooling kiln 401 through a chute. The product obtained from roasting enters the cooling kiln 401 from the discharge port of the kiln tail 104 through the chute. The cooling kiln 401 adopts circulating water wall cooling, and the bottom of its tail is provided with a product discharge rotary valve 403. The cooled product is sent out through the product discharge rotary valve 403.

[0054] Referring to Figure 1, the arrows in Figure 1 indicate the flow direction of fluid in the corresponding section of the pipeline, raw material in the feeding mechanism 2, and material inside the rotary kiln body 1. The main flow direction of the material inside the rotary kiln body 1 is from the kiln head 101 towards the kiln tail 104. The specific path of the material's tumbling motion inside the rotary kiln body 1 follows conventional design in this field and will not be elaborated further. The overall movement process of the material in this lithium iron phosphate sintering preparation device is as follows: Raw material enters the kiln head 101 from the feeding mechanism 2. The material tumbles in the rotary kiln body 1 towards the kiln tail 104. The material passes through the kiln section corresponding to the heating section 102, which is used to raise the temperature of the material. The material undergoes sintering inside the kiln section corresponding to the heat preservation section 103. After sintering, it enters the kiln tail 104 and is discharged into the discharge mechanism 4. The volatiles inside the rotary kiln body 1 are discharged through the top of the kiln tail 104 to the volatiles treatment mechanism 3.

[0055] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A rotary kiln for sintering lithium iron phosphate, characterized in that, The rotary kiln body (1) includes a kiln head (101), a heating section (102), a heat preservation section (103), and a kiln tail (104) arranged sequentially along the length of the kiln body (1). The heat preservation section (103) is fitted with a heat preservation section flue gas chamber (1031) on the outside of the kiln wall. The bottom and top of the heat preservation section flue gas chamber (1031) are provided with multiple parallel and spaced flue gas inlets and multiple spaced flue gas outlets. The flue gas inlets and outlets are staggered along the axial direction of the heat preservation section flue gas chamber (1031). The flue gas inlets are used to introduce high-temperature flue gas.

2. The rotary kiln for lithium iron phosphate sintering according to claim 1, characterized in that, The rotary kiln also includes a first air inlet pipe (105) and a first air outlet pipe (106); the first air inlet pipe (105) includes multiple parallel and spaced air inlet branches, and the first air outlet pipe (106) includes multiple parallel and spaced air outlet branches. The air inlet branches and the air outlet branches are respectively set to correspond to the flue gas inlet and the flue gas outlet in the flue gas chamber (1031) of the heat preservation section, and are both set perpendicular to the length direction of the rotary kiln body (1).

3. The rotary kiln for sintering lithium iron phosphate according to claim 1 or 2, characterized in that, The number of flue gas inlets or outlets in the flue gas chamber (1031) of the insulation section is at least 3, and the number of flue gas outlets differs from the number of flue gas inlets by one.

4. The rotary kiln for lithium iron phosphate sintering according to claim 2, characterized in that, The heating section (102) is fitted with a heating section flue gas chamber (1021) on the outside of the kiln wall. The flue gas inlet of the heating section flue gas chamber (1021) is connected to the flue gas outlet of the heat preservation section flue gas chamber (1031) to provide high-temperature flue gas to the heating section flue gas chamber (1021).

5. A lithium iron phosphate sintering preparation apparatus, characterized in that, The device includes a feeding mechanism (2), a discharging mechanism (4), a flue gas generating mechanism (5), and a rotary kiln as described in any one of claims 1-4, wherein the kiln head (101) is connected to the feeding mechanism (2); the kiln tail (104) is connected to the discharging mechanism (4); and the flue gas inlet in the flue gas chamber (1031) of the heat preservation section is connected to the flue gas generating mechanism (5) for introducing high-temperature flue gas into the flue gas chamber (1031) of the heat preservation section.

6. The lithium iron phosphate sintering preparation apparatus according to claim 5, characterized in that, The flue gas generating mechanism (5) includes a gas-fired heated hot air furnace (503), and the high-temperature flue gas outlet in the hot air furnace (503) is connected to the flue gas inlet in the flue gas chamber (1031) of the heat preservation section.

7. The lithium iron phosphate sintering preparation apparatus according to claim 6, characterized in that, The flue gas generating mechanism (5) also includes an air heat exchanger (501), which is used to heat the combustion air with the high-temperature flue gas discharged from the flue gas outlet in the rotary kiln. The air heat exchanger (501) is connected to the hot blast stove (503) and is used to introduce the heated combustion air into the hot blast stove (503).

8. The lithium iron phosphate sintering preparation apparatus according to any one of claims 5-7, characterized in that, The top of the kiln tail (104) is connected to the volatile matter treatment mechanism (3).

9. The lithium iron phosphate sintering preparation apparatus according to claim 8, characterized in that, The volatile matter treatment mechanism (3) includes a high-temperature dust collector (301) and a volatile matter induced draft fan (302) connected to each other. The high-temperature dust collector (301) is connected to the top of the kiln tail (104). The volatile matter induced draft fan (302) is connected to the hot blast stove (503) in the flue gas generating mechanism (5) and is used to provide fuel to the hot blast stove (503).

10. The lithium iron phosphate sintering preparation apparatus according to any one of claims 5-7, characterized in that, The feeding mechanism (2) includes a feeding deoxidation chamber (201), a feeding buffer chamber (202), a deoxidation nitrogen channel (205), and a rotary kiln atmosphere nitrogen channel (204). The feeding deoxidation chamber (201), the feeding buffer chamber (202), and the kiln head (101) are connected in sequence. The feeding deoxidation chamber (201) has a deoxidation nitrogen channel (205) connected to one side. The rotary kiln atmosphere nitrogen channel (204) is connected to the kiln head (101). And / or the discharging mechanism (4) includes a cooling kiln (401) and a cooling kiln atmosphere nitrogen channel (402). The head of the cooling kiln (401) is connected to the bottom of the kiln tail (104), and the cooling kiln atmosphere nitrogen channel (402) is connected to the tail of the cooling kiln (401).

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