An integrated device for drying lithium iron manganese phosphate and lithium iron phosphate

Abstract

The utility model relates to an integrated device for feeding and drying lithium iron manganese phosphate and lithium iron phosphate, and belongs to the technical field of synthesis and drying of lithium iron manganese phosphate and lithium iron phosphate. The integrated device comprises a steam rotary dryer, a plurality of steam heat exchange tubes are arranged inside the cylinder of the rotary dryer, a return spiral is arranged outside the cylinder, a feed port of the return spiral is opened at the tail end of the cylinder, and a discharge port is located at the front end of the cylinder, an atomizing feeding device and an air inlet are arranged at the front end of the rotary dryer, a discharge hood and a rotary joint are arranged at the tail end, and the rotary joint is connected to the steam heat exchange tube and the steam heat source network. The integrated device designed by the utility model adopts a rotary dryer with a return spiral, and the feeding reaction is completed at the front end of the dryer by spray feeding and returning the material, and the drying of the material is completed as the drum rotates, so as to realize the integration of feeding and drying.

Description

Technical Field

[0001] The utility model relates to the technical field of synthesis and drying of lithium iron manganese phosphate and lithium iron phosphate, and in particular to an integrated device for feeding and drying lithium iron phosphate and lithium iron phosphate. Background Art

[0002] Lithium iron manganese phosphate and lithium iron phosphate are new lithium-ion battery cathode materials with the advantages of high safety, high cycle life, low cost and wide raw material sources, becoming the first choice for new energy vehicles and energy storage scenarios. At present, there are generally two process routes in the industrial production of lithium iron manganese phosphate and lithium iron phosphate: solid phase method and wet method. One typical wet process is the self-thermal evaporation liquid phase method to synthesize nano lithium iron manganese phosphate and lithium iron phosphate, that is, at room temperature and pressure, the raw materials such as lithium source, iron source, phosphorus source, manganese source and auxiliary materials are mixed to react spontaneously. After the reaction is exothermic, the water evaporates quickly and the reaction stops automatically, obtaining the precursor material of nano lithium iron manganese phosphate or lithium iron phosphate.

[0003] The existing wet production processes of lithium manganese iron phosphate and lithium iron phosphate have the following main disadvantages:

[0004] 1. In the existing process, the precursor material delivery section and drying section are two independent units, which need to be completed in different equipment. There are problems such as low process continuity, low production efficiency of split equipment and high equipment investment;

[0005] 2. The existing process adopts a static feeding method in the feeding stage, that is, the raw material solution is mixed in a certain proportion and then placed in a material tank for feeding. The feeding process takes a long time, and the product after feeding is in a block shape, which is not conducive to the subsequent drying process;

[0006] 3. A large amount of tail gas is generated. In the existing process, a fluidized bed is generally used as a drying treatment equipment. A large amount of tail gas is generated during the drying process, and the cost of tail gas treatment is relatively high. Summary of the invention

[0007] In order to solve the problems in the prior art, this utility model patent designs an integrated device for discharging and drying lithium iron phosphate and lithium iron phosphate materials to solve the problems of poor continuity of the existing lithium iron phosphate and lithium iron phosphate precursor material production processes, unsatisfactory discharging effects, and large amount of drying exhaust gas.

[0008] The technical solution adopted by the utility model is: the integrated device includes a rotary dryer, a return spiral is arranged on the outside of the cylinder of the rotary dryer, the feed port of the return spiral is opened at the tail end of the cylinder, and the discharge port is located at the front end of the cylinder, the front end of the rotary dryer is provided with an atomizing feed device and an air inlet, the atomizing feed device is connected to the temporary storage tank of the precursor raw material through a pressurized pipeline, the air inlet is connected to a heating air supply device, and the tail end of the rotary dryer is provided with a discharge hood.

[0009] Furthermore, the rotary dryer is a steam dryer, and a plurality of steam heat exchange tubes are evenly arranged circumferentially inside the cylinder, a steam chamber is provided at the tail to connect the steam heat exchange tubes, and a rotary joint is provided at the tail end of the rotary dryer, the rotary joint is connected to the steam chamber and the steam pipe network, and the rotary joint is also provided with a condensate outlet.

[0010] Furthermore, the feed port of the return screw is provided with a gate for adjusting the opening of the feed port.

[0011] Furthermore, an exhaust port is provided at the top of the discharge hood, and the exhaust port is connected to an exhaust gas treatment device.

[0012] Furthermore, the exhaust gas treatment device includes a bag dust collector and an induced draft fan connected by pipelines, and the air inlet end of the bag dust collector is connected to the exhaust port of the discharge hood.

[0013] Furthermore, the heating and air supply device includes a fan, an air filter and a heat exchanger connected in sequence, the heat exchanger is connected to a steam pipe network, and the air outlet pipe of the heat exchanger is connected to the air inlet of the rotary dryer.

[0014] Furthermore, the atomizing feeding device includes a feeding pipe and a plurality of atomizing nozzles, the plurality of atomizing nozzles are evenly arranged on the feeding pipe, with the nozzles facing downward and arranged perpendicularly to the plane of the material layer, the outer end of the feeding pipe is connected to a temporary storage tank and compressed air, and a screw pump is arranged on the connecting pipeline between the feeding pipe and the temporary storage tank.

[0015] Compared with the prior art, the advancement of the integrated device for drying lithium iron phosphate and lithium iron phosphate material delivery designed by the utility model patent is:

[0016] The rotary dryer of the utility model patent is provided with a return spiral, and an atomizing feeding device is provided at the front end of the rotary dryer. The mixed feeding of the precursor material is completed at the front end of the rotary dryer by using the spray feeding and the return material. The material gradually moves to the rear end as the cylinder rotates, and heat is exchanged with the heat exchange tube during the movement to complete the drying. The material feeding and drying processes are completed in one device, with high production efficiency and low equipment investment.

[0017] The heat exchange tubes in the rotary dryer are conducive to promoting the occurrence of self-heating reaction of materials and accelerating the drying process of materials.

[0018] The rotary dryer requires very little hot air during the entire drying process and does not generate a large amount of waste gas and tail gas, greatly reducing the cost of tail gas treatment.

[0019] The rotary dryer is equipped with an atomizing feeding device, and the spray granulation method can optimize the shape and size distribution of material particles, which helps to improve the quality of the prepared products, which is particularly important in the field of battery materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a lithium manganese iron phosphate and lithium iron phosphate feeding and drying integrated device.

[0021] In the figure, 1 is a rotary dryer, 2 is an atomizing feeding device, 3 is a return screw, 4 is a discharge cover, 5 is a rotary joint, 6 is a heat exchanger, 7 is an air filter, 8 is a bag dust collector, and 9 is an induced draft fan. DETAILED DESCRIPTION

[0022] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments. The technical solutions in the embodiments of the utility model are clearly and completely described, and the described embodiments are only embodiments of a part of the invention, not all of it. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0023] like Figure 1 As shown, the utility model patent designs an embodiment of an integrated device for drying lithium iron manganese phosphate and lithium iron phosphate. In this embodiment, the integrated device includes a steam rotary dryer 1. A return screw 3 is arranged on the outer side of the cylinder of the rotary dryer 1. The feed port of the return screw 3 is opened at the tail end of the cylinder and is located in front of the discharge port of the rotary dryer 1. The discharge port is located at the front end of the cylinder. A gate for adjusting the opening of the feed port is arranged at the feed port. The front end of the rotary dryer 1 is provided with an atomizing feed device 2 and an air inlet. The atomizing feed device 2 includes a feed pipe and a plurality of atomizing nozzles. The feed pipe extends into the rotary dryer 1 along the axis. The plurality of atomizing nozzles are evenly arranged on the feed pipe. The nozzles of the atomizing nozzles are all downward and arranged perpendicular to the plane of the material layer. The outer end of the feed pipe is connected to the temporary storage tank and compressed air of the precursor raw material. A screw pump is also arranged on the connecting pipeline between the feed pipe and the temporary storage tank. The air inlet of the rotary dryer 1 is connected to a heating and air supply device, which includes a fan, an air filter 7 and a heat exchanger 6 connected in sequence. The heat exchanger 6 is connected to a steam network, and the steam heats the air to form hot air which is then sent to the rotary dryer 1.

[0024] A discharge cover 4 is arranged near the tail end of the rotary dryer 1, and the discharge cover 4 is connected to the cylinder body in a sealed rotation manner, and a discharge port is opened at the bottom thereof, and a discharge valve is connected thereto. An exhaust port is opened at the top, and an exhaust gas treatment device is connected to the exhaust port.

[0025] A number of steam heat exchange tubes are evenly arranged along the circumferential direction inside the cylinder of the rotary dryer 1. Each steam heat exchange tube is arranged along the axial direction. A steam chamber is arranged at the tail end to communicate with each steam heat exchange tube. A rotary joint 5 is arranged at the tail end of the rotary dryer 1. The rotary joint 5 is connected to the steam chamber and the steam pipe network. The rotary joint 5 is also provided with a condensate outlet connected to the condensate recovery pipeline to send steam into the steam heat exchange tube in the rotary dryer 1 and discharge the condensate formed after the steam heat exchange.

[0026] The exhaust gas treatment device includes a bag dust collector 8 and an induced draft fan 9 connected by pipelines. The air inlet end of the bag dust collector 8 is connected to the exhaust port of the discharge hood 4. The induced draft fan 9 forms a negative pressure to allow the exhaust gas to enter the bag dust collector 8. After treatment, the exhaust gas is sent to the subsequent exhaust gas treatment system.

[0027] When the lithium manganese iron phosphate and lithium iron phosphate material delivery and drying integrated device disclosed in the utility model patent is used,

[0028] The precursor raw material (solution) of lithium manganese iron phosphate or lithium iron phosphate is input into the temporary storage tank, which is constantly stirred to keep the material in a liquid state. Then the material is pumped into the atomizing feeding device inside the rotary dryer with a screw pump. The front section of the rotary dryer is the spray reaction zone, where the material is sprayed into a mist. The mist material contacts and exchanges heat with the return material in a high-temperature state to induce a material reaction, which causes the droplets to quickly dehydrate into particles.

[0029] Behind the spray reaction zone is the heating and drying zone. Since the rotary dryer's cylinder has a certain installation angle from the feed end to the discharge end, the material will move to the heating and drying zone as the cylinder rotates after feeding. Driven by the rotary dryer drum, the material is scattered around the steam heat exchange tube and gradually moves to the tail discharge end. In this process, the material contacts the heat exchange tube and exchanges heat with the steam in the heat exchange tube. The material heats up and dehydrates, and the moisture content is further reduced. Finally, the moisture content at the discharge end of the rotary dryer is reduced to the minimum. A part of the dry material is discharged through the discharge valve at the bottom of the discharge hood, and the other part of the material enters the return spiral through the feed port and returns to the spray reaction zone at the front end of the dryer as return material.

[0030] The rotary dryer uses saturated steam as the drying heat source. The steam used for drying comes from the steam pipe network. The steam pipe of the rotary joint at the tail end of the rotary dryer is equipped with a flow meter, pressure gauge, thermometer and regulating valve group, which can monitor and adjust the steam supply in real time to control the heating temperature in the dryer. Through the steam heat exchange pipe, the steam and the material exchange heat indirectly, release heat and gradually condense. The generated condensed water is collected in the "steam chamber" at the tail end of the rotary dryer, and the condensed water is discharged from the steam chamber by the siphon. After passing through the steam trap, the condensed water enters the recovery pipe network.

[0031] The rotary dryer uses ambient air as the moisture-carrying gas. The heat exchanger heats the air. After heating, the air temperature rises before entering the rotary dryer, which can improve the dehydration efficiency of the device. Hot air enters the rotary dryer from the air inlet. Under the action of the induced draft fan, the dryer is in a slightly negative pressure state, causing the moisture-carrying gas to flow from the feed end to the discharge end. There is a relative humidity gradient between the material and the moisture-carrying gas, which promotes the migration of moisture from the material to the moisture-carrying gas, and the moisture content of the material gradually decreases, while the moisture content of the moisture-carrying gas gradually increases. At the air outlet, the moisture content of the moisture-carrying gas reaches the maximum, and is discharged from the air outlet on the upper part of the discharge hood of the rotary dryer, and enters the subsequent tail gas treatment system after being treated by the bag dust collector.

[0032] The above contents are only preferred embodiments of the present invention and cannot be used to limit the scope of implementation of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. A lithium manganese iron phosphate and lithium iron phosphate material delivery and drying integrated device, characterized in that: The integrated device includes a rotary dryer, a return screw is arranged on the outside of the cylinder of the rotary dryer, the feed port of the return screw is opened at the tail end of the cylinder, and the discharge port is located at the front end of the cylinder, an atomizing feed device and an air inlet are arranged at the front end of the rotary dryer, the atomizing feed device is connected to the temporary storage tank of the precursor raw material through a pressurized pipeline, the air inlet is connected to a heating air supply device, and a discharge hood is arranged at the tail end of the rotary dryer.

2. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 1, characterized in that: The rotary dryer is a steam type dryer, and a plurality of steam heat exchange tubes are evenly arranged in the circumferential direction inside the cylinder. A steam chamber is arranged at the tail to connect the steam heat exchange tubes. A rotary joint is arranged at the tail end of the rotary dryer, and the rotary joint is connected to the steam chamber and the steam pipe network. The rotary joint is also provided with a condensed water outlet.

3. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 2, characterized in that: The feed inlet of the return screw is provided with a gate plate for adjusting the opening of the feed inlet.

4. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 3, characterized in that: An exhaust port is provided on the top of the discharge cover, and an exhaust gas treatment device is connected to the exhaust port.

5. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 4, characterized in that: The tail gas treatment device comprises a bag dust collector and an induced draft fan connected by pipelines, and the air inlet end of the bag dust collector is connected to the exhaust port of the discharge hood.

6. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 5, characterized in that: The heating and air supply device comprises a fan, an air filter and a heat exchanger which are connected in sequence, and the heat exchanger is connected to a steam pipe network.

7. The integrated device for dispensing and drying lithium iron phosphate and lithium manganese phosphate according to claim 6, characterized in that: The atomizing feeding device includes a feeding pipe and a plurality of atomizing nozzles, which are evenly arranged on the feeding pipe with nozzles facing downward and arranged perpendicular to the plane of the material layer. The outer end of the feeding pipe is connected to a temporary storage tank and compressed air, and a screw pump is arranged on the connecting pipeline between the feeding pipe and the temporary storage tank.

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