Iron phosphate sintering rotary kiln

Abstract

The utility model discloses an iron phosphate sintering rotary kiln which comprises a hearth and a roller, a plurality of shoveling plates are arranged on the inner wall of the roller in the circumferential direction, and a plurality of anti-radiation plates which are matched with the shoveling plates to enable materials to be evenly mixed are fixed on the inner wall of the roller at intervals. The anti-radiation plate is in a gear shape and comprises a main plate used for blocking materials in the middle, and toothed plates matched with the shoveling plates to enable the materials to be evenly mixed are arranged on the periphery of the main plate at intervals. Materials uniformly pass through a gap between the anti-radiation plate and the inner wall of the roller and are raised to be uniformly heated by matching with the shoveling plate, the retention time of the materials is long, the sintering is more uniform, impurities in the materials are promoted to be fully volatilized, the sintering performance of iron phosphate is further improved, and the energy consumption is reduced; the anti-radiation plate has a certain blocking effect on introduced hot air, the mixing time of the hot air and gas volatilized in the roller is prolonged, the mixing efficiency of the hot air and the gas volatilized in the roller is improved, moisture is prevented from being condensed in a pipeline, the dehumidification efficiency is improved, meanwhile, the removal efficiency of volatile substances is improved, and the content of S in an iron phosphate finished product is greatly reduced.

Description

Technical Field

[0001] This utility model relates to a ferric phosphate production equipment, and more particularly to a ferric phosphate sintering rotary kiln. Background Technology

[0002] With the continuous development of new energy sources, lithium-ion batteries are gradually replacing traditional nickel-metal hydride batteries due to their advantages such as high capacity, good cycle life, no pollution, and long lifespan. The cathode material of lithium-ion batteries plays a decisive role in battery performance, mainly including lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and ternary materials. Among them, lithium iron phosphate has advantages such as high safety, long cycle life, and low manufacturing cost, making it one of the most promising cathode materials for lithium-ion batteries. However, the sintering process of lithium iron phosphate is one of the key steps affecting its performance. Currently, rotary kilns are mostly used for sintering, but the material flow inside traditional rotary kilns is not uniform enough, resulting in inconsistent sintering effects and poor consistency in the finished lithium iron phosphate products, seriously affecting the performance of lithium iron phosphate batteries. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to solve the problem of poor uniformity of sintered ferric phosphate in traditional rotary kilns, and to provide a rotary kiln for sintering ferric phosphate.

[0004] Technical solution: The ferric phosphate sintering rotary kiln of this utility model includes a kiln, which includes a furnace chamber and a drum. Multiple lifting plates are arranged circumferentially on the inner wall of the drum. Multiple radiation shielding plates that cooperate with the lifting plates to make the material evenly mixed are fixed at intervals on the inner wall of the drum. The radiation shielding plate is gear-shaped, including a main plate in the middle for blocking the material, and toothed plates that cooperate with the lifting plates to make the material evenly mixed on the outer periphery of the main plate.

[0005] Furthermore, multiple protruding plates are spaced apart on the inner wall of the drum, and the toothed plates are threadedly connected to the protruding plates to fix the radiation shielding plate to the inner wall of the drum. During the sintering process, the drum rotates continuously, and the material enters and rotates forward. When the material encounters the radiation shielding plate, it passes through the gap between the radiation shielding plate and the inner wall of the drum due to the obstruction of the radiation shielding plate. The lifting plates then lift the material, allowing it to be heated evenly.

[0006] Furthermore, the toothed plates are rectangular in structure, with 4 to 10 sets. The toothed plates are 40 to 60 cm long, 20 to 35 cm wide, and 1 to 5 cm thick. The main plate is circular in structure, with a thickness of 1 to 5 cm. By adjusting the size and thickness of the main plate and toothed plates, as well as the number of sets of toothed plates, in conjunction with the diameter of the furnace drum, the uniformity of material mixing can be improved. In addition, the size of the main plate and toothed plates, especially the main plate, should not be too large. This ensures that hot air convects with the advancing material within the drum, while the heat radiation plates provide some obstruction to the introduced hot air, increasing the residence time and dispersion of hot air in the material, thereby improving the removal efficiency of volatile gases and the dehumidification efficiency.

[0007] Furthermore, the roller is equipped with an exhaust port at the feed end and a hot air blower at the discharge end for introducing hot air to dehumidify the roller. A bag filter is also installed at the feed end of the roller to filter and recover the air discharged from the exhaust port. Dehumidified hot air is introduced into the end of the roller, mixing with the evaporated moisture to form low-moisture exhaust gas, which is discharged from the exhaust port at the feed end. A portion of the hot air is mixed with the exhaust air according to the dehumidification temperature to increase the exhaust temperature, preventing condensation from forming in the exhaust duct and dust collection equipment, which would affect the sintering performance of the material.

[0008] Beneficial Effects: Compared with the prior art, this utility model has the following advantages: 1. By setting radiation shielding plates at intervals, the material needs to pass evenly through the gap between the radiation shielding plate and the inner wall of the drum after a certain distance. In conjunction with the lifting plates, the material is lifted up so that it is heated evenly, improving the uniformity of ferric phosphate sintering. At the same time, it promotes the full volatilization of impurities in the material, further improving the sintering performance of ferric phosphate; 2. The radiation shielding plates have a certain blocking effect on the material during the forward sintering process, increasing the residence time of the material in the rotary kiln, further improving the sintering performance of ferric phosphate while reducing energy consumption; 3. The radiation shielding plates have a certain blocking effect on the introduced hot air, increasing the mixing time and mixing efficiency with the volatile gases in the drum, avoiding the condensation of moisture in the pipes, improving the dehumidification efficiency, and improving the removal efficiency of volatile substances. The sulfur content in the finished ferric phosphate product is greatly reduced. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of this utility model;

[0010] Figure 2 This is a cross-sectional view of the rotary kiln of this utility model. Detailed Implementation

[0011] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0012] like Figure 1The illustrated ferric phosphate sintering apparatus includes a kiln 1, which comprises a furnace chamber 2 and a drum 3. A heating device 9 is installed at the bottom of the furnace chamber 2, and an insulation layer is installed on the outer wall of the kiln 1. The drum 3 is equipped with a rotating mechanism 8, and multiple lifting plates 10 are spaced apart on the circumference of the inner wall of the drum 3. Multiple radiation-shielding plates 4 are spaced apart between the lifting plates 10 to cooperate with the lifting plates 10 and ensure uniform mixing of materials. The radiation-shielding plates 4 are gear-shaped, including a circular main plate 4-1 in the middle for blocking materials, and rectangular toothed plates 4-2 spaced apart on the outer periphery of the main plate 4-1 to cooperate with the lifting plates 10 and ensure uniform mixing of materials. Multiple protruding plates 13 are provided on the inner wall of the drum 3, and the toothed plates 4-2 are threadedly connected to the protruding plates 13 to fix the radiation-shielding plates 4 to the inner wall of the drum 3. An exhaust port 11 is provided at the feed end of the drum 3, and a hot air blower 12 is provided at the discharge end to introduce hot air for dehumidifying the drum 3. A bag filter 6 is also provided at the feed end of the drum 3 to filter and recover the air discharged from the exhaust port 11. An induced draft fan 5 is installed on the bag filter 6, and a screw feeder 7 is installed at the bottom of the bag filter 6 to collect the material discharged from the exhaust port 11 and send it back to the kiln 1 for re-sintering, preventing material loss and direct discharge that could impact the environment. Dehumidifying hot air is introduced into the end of the drum 3. The radiation shield 4 provides some obstruction to the introduced hot air, increasing the mixing time and efficiency with the volatile gases inside the drum 3, preventing moisture condensation in the pipes, and improving both dehumidification efficiency and the removal efficiency of volatile substances.

[0013] like Figure 2 As shown, the kiln specifications are Φ2.80×25m, the diameter of the drum 3 is 280cm, the toothed plate 4-2 is a rectangular structure with 8 sets, the length of the toothed plate 4-2 is 50cm, the width is 25cm, and the thickness is 2cm, and the main plate 4-1 is a circular structure with a thickness of 2cm. Alternatively, depending on the requirements for uniformity in the sintering performance of the material, the requirements for material-hot air convection, and the diameter of the drum 3, 4 to 10 sets of toothed plates 4-2 can be selected, with a length of 40 to 60cm, a width of 20 to 35cm, and a thickness of 1 to 5cm, and the thickness of the main plate 4-1 is 1 to 5cm. By adjusting the size and thickness of the main plate 4-1 and the toothed plates 4-2, as well as the number of sets of toothed plates 4-2, the uniformity of material mixing and sintering, as well as the contact time and contact area between hot air and the material, can be improved, thereby increasing the dehumidification efficiency and the removal efficiency of volatile gases.

[0014] During the firing process, the powder is fed into the drum 3 through multiple spiral guide plates at the feed end. The drum 3 is divided into several different temperature zones. A heating device 9 is installed at the bottom of the furnace 2 to heat the drum 3. The heat for material heating and moisture evaporation comes from contact heat transfer (inter-wall heat transfer) with the high-temperature drum wall and radiative heat transfer from the high-temperature drum wall to the material and the air inside the drum, with contact heat transfer with the drum wall being the main source. In the heating section, the material rotates and moves inside the drum 3, and the temperature gradually and continuously rises, with volatile components such as moisture continuously being removed from the material. In the roasting section, the roasting temperature and residence time are set. When the material passes through the radiation shielding plate 4, due to the obstruction of the radiation shielding plate 4, the material passes evenly through the gap between the radiation shielding plate 4 and the inner wall of the drum 3. Then, the lifting plate 10 lifts the material, so that the material is heated and sintered evenly to meet the roasting requirements. In the cooling section, the material is discharged from the high-temperature rotary kiln drum 3 and cooled before entering the next process.

[0015] Material moisture discharge process: The material is heated inside drum 3, and volatile components such as moisture are continuously evaporated from the material and enter drum 3. Dehumidifying hot air is introduced into the end of drum 3. The hot air mixes with the evaporated moisture to form exhaust gas with low moisture content, which is discharged from the exhaust port at the feed end. According to the dehumidification temperature, some hot air is mixed to increase the exhaust temperature, preventing the discharged moisture from forming condensation in the exhaust duct and bag filter 6. The radiation shield 4 has a certain blocking effect on the introduced hot air, increasing the mixing time and mixing efficiency with the volatile gases in drum 3, avoiding moisture condensation in the duct, and improving the dehumidification efficiency while improving the removal efficiency of volatile substances. The S content in the finished iron phosphate product is greatly reduced.

Claims

1. A rotary kiln for ferric phosphate sintering, comprising a kiln (1), wherein the kiln (1) includes a furnace chamber (2) and a drum (3), wherein a plurality of lifting plates (10) are arranged circumferentially on the inner wall of the drum (3), characterized in that, The inner wall of the roller (3) is fixed with a plurality of radiation shielding plates (4) that cooperate with the lifting plate (10) to make the material evenly mixed; the radiation shielding plate (4) is gear-shaped, including a main plate (4-1) in the middle for blocking the material, and toothed plates (4-2) that cooperate with the lifting plate (10) to make the material evenly mixed on the outer periphery of the main plate (4-1).

2. The rotary kiln for ferric phosphate sintering according to claim 1, characterized in that, The inner wall of the roller (3) is provided with a plurality of protruding plates (13) spaced apart, and the toothed plate (4-2) is threadedly connected to the protruding plates (13).

3. The rotary kiln for ferric phosphate sintering according to claim 1, characterized in that, The toothed plate (4-2) is a rectangular structure, and 4 to 10 sets are provided.

4. The ferric phosphate sintering rotary kiln according to claim 3, characterized in that, The toothed plate (4-2) is 40-60cm long, 20-35cm wide, and 1-5cm thick.

5. The rotary kiln for ferric phosphate sintering according to claim 1, characterized in that, The motherboard (4-1) has a circular structure.

6. The ferric phosphate sintering rotary kiln according to claim 5, characterized in that, The thickness of the motherboard (4-1) is 1 to 5 cm.

7. The rotary kiln for ferric phosphate sintering according to claim 1, characterized in that, The roller (3) is provided with an exhaust port (11) at the feed end and a hot air blower (12) at the discharge end for introducing hot air to dehumidify the roller (3).

8. The ferric phosphate sintering rotary kiln according to claim 6, characterized in that, The feed end of the roller (3) is also equipped with a bag filter (6) that filters and recovers the air discharged from the exhaust port (11).

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