Spray drying device for preparing lithium iron phosphate and preparation process

Abstract

The invention relates to the technical field of lithium iron phosphate preparation, in particular to a spray drying device for lithium iron phosphate preparation and a preparation process, the spray drying device comprises a tower body, and a centrifugal atomizer is embedded and fixedly arranged on the top surface of the tower body; the air injection flow guide mechanism is arranged in the tower body and comprises air guide rings, separation sleeves and telescopic sleeves, the multiple separation sleeves are arranged in a concentric array mode from inside to outside, the air guide rings are fixedly connected to the bottom faces of the separation sleeves through bolts, and air outlet sleeves with the lower ends connected to the top faces of the same air guide rings are arranged at the lower ends of the inner walls and the outer walls of the separation sleeves in an attached mode; an air outlet sleeve is only arranged on one side of the inner wall of the separation sleeve on the outermost air guide ring; circulation cavities are formed in connecting bodies of the air guide rings and the air outlet sleeves, the adjacent circulation cavities are connected through a plurality of communicating pipes arrayed in the circumferential direction, the spray drying device can effectively dry slurry on the premise that the slurry falling distance is reduced, the drying effect is good, the overall practicability is high, and the preparation cost can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium iron phosphate preparation, and particularly relates to a spray drying device for lithium iron phosphate preparation and a preparation process. BACKGROUND

[0002] Lithium ion batteries have the advantages of high working voltage and high energy density, and are the most potential secondary batteries. Lithium iron phosphate, as a positive material of lithium ion batteries, has the advantages of high capacity, long cycle life, high thermal stability, environmental friendliness and low cost. In the preparation of high-density lithium iron phosphate, iron phosphate and lithium carbonate are mixed in a certain proportion to form a slurry. The prepared slurry is subjected to powder drying treatment by a spray drying device, and finally, the lithium iron phosphate product can be obtained by sintering and crushing. For example, the existing public document CN117298626B-high-density lithium iron phosphate preparation spray drying device and lithium iron phosphate preparation process and the existing public document CN103506058B-microcapsule spray drying device both disclose a spray drying device. The above spray drying device can realize drying during the preparation of lithium iron phosphate. However, the existing spray drying device still has the following shortcomings in actual use: 1. The existing spray drying device generally sprays slurry and hot air from the upper end of the tower body. Therefore, the flow direction of hot air and the falling direction of slurry are the same. In a fixed path, the falling time of slurry is shorter than that of gravity alone. Therefore, in order to ensure sufficient drying of the slurry, the height of the tower body is generally designed to be higher (to increase the falling distance of the slurry). The design of a higher tower body increases the manufacturing cost and increases the safety hazard (the center of gravity of the tower body is higher). 2. In use, the existing spray drying device sprays slurry through a centrifugal atomizer. Therefore, the particle size of the sprayed slurry is different (different particle sizes result in different angular momentum of centrifugal particles, which is manifested as umbrella-shaped spraying of the slurry). The fixed path design of the tower body leads to unsatisfactory drying effect of large particles of slurry, and ultimately leads to poor quality of dried lithium iron phosphate. Therefore, it is necessary to improve the existing technology to solve the above technical problems. SUMMARY

[0003] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title. Such simplifications or omissions cannot be used to limit the scope of the present application.

[0004] In view of the above-mentioned existing spray drying device in use, hot air is sprayed from the upper end of the tower body, which indirectly causes the problem of high tower height, a spray drying device for lithium iron phosphate preparation is proposed.

[0005] To solve the above technical problems, the present application provides the following technical scheme: a spray drying device for lithium iron phosphate preparation, comprising a tower body, a centrifugal atomizer is embedded and fixed on the top surface of the tower body; and a jet flow guide mechanism arranged in the tower body, comprising a gas guide ring, a separation sleeve and an extension sleeve, a plurality of separation sleeves are arranged in a concentric array from inside to outside, a gas guide ring is fixedly connected to the bottom surface of the separation sleeve by bolts, a gas outlet sleeve is attached to the lower end position of the inner and outer walls of the separation sleeve and connected to the top surface of the same gas guide ring, and only one gas outlet sleeve is arranged on the inner wall of the outermost gas guide ring; a flow-through cavity is formed in the connecting body of the gas guide ring and the gas outlet sleeve, and adjacent flow-through cavities are connected by a plurality of circumferentially arrayed communication pipes, the upper end position of the gas outlet sleeve is arranged as a first inclined surface, and a plurality of gas outlet holes are formed in the first inclined surface in a circumferential array and communicate with the flow-through cavities, the inner side of the outermost separation sleeve is a flow guide cavity, and the flow guide cavity is divided into a plurality of flow guide cavity regions by the plurality of gas outlet sleeves, the number of gas outlet holes on the plurality of gas outlet sleeves in the same flow guide cavity region is equal, and the number of gas outlet holes on the gas outlet sleeves in each flow guide cavity region increases from inside to outside; a gas collecting plate is fixedly arranged on the outer wall of the outermost gas guide ring and communicates with the flow-through cavity, and an air inlet pipe is fixedly arranged on the bottom surface of the gas collecting plate and extends to the outside of the tower body.

[0006] The beneficial effects of the present application are: when the spray drying device is used, the heated air enters through the air inlet pipe, is guided through the flow-through cavity and the communication pipe, and finally the hot air is sprayed out of the gas outlet holes above the gas outlet sleeve, the sprayed hot air flows upward, and the slurry sprayed by the centrifugal atomizer flows downward, so that the flow directions of the hot air and the slurry are opposite when they contact each other, which can effectively reduce the falling speed of the slurry, shorten the falling distance of the slurry (tower height) and effectively dry the slurry, save manufacturing cost, improve overall practicability, and effectively reduce safety hazards.

[0007] As a preferred scheme of the spray drying device for lithium iron phosphate preparation, the top surface of the centrifugal atomizer is fixedly provided with a slurry inlet pipe, and the bottom surface of the tower body is fixedly provided with a discharge pipe.

[0008] As a preferred scheme of the spray drying device for lithium iron phosphate preparation, the outer side wall of the outermost gas guide ring is fixedly provided with a connecting piece in a symmetrical manner, the connecting piece is fixedly connected to the outermost separation sleeve by bolts, and the connecting piece is also fixedly connected to the connecting plate fixedly arranged on the inner wall of the tower body by bolts.

[0009] In view of the problem that the existing spray drying device cannot realize effective drying in the face of different sizes of lithium iron phosphate particles, a spray drying device for preparing lithium iron phosphate is further improved, wherein: a telescopic groove for sliding sleeve connection of the telescopic sleeve is formed on the top surface of the partition sleeve, and an end ring is fixedly arranged on the top surface of the telescopic sleeve, and a plurality of end rings are connected and fixed by a connecting strip arranged along the radial direction of the end ring; a powder collecting cover is fixedly arranged on the top surface of the outermost end ring in the circumferential direction and is attached to the inner wall of the tower body, an L-shaped plate is fixedly arranged on one side of the bottom surface of the powder collecting cover, a screw column is screw-connected to the horizontal plate at the lower end of the L-shaped plate, the lower end of the screw column is fitted into the output end of the motor, and the motor is fixedly connected to the inner wall of the tower body.

[0010] Another beneficial effect of the present application is that: when the spray drying device is in use, the flow guide cavity is divided into multiple flow guide cavity zones by the partition sleeve, and because the number of air outlet holes on the air outlet sleeves in the same flow guide cavity zone is equal, and the number of air outlet holes on the air outlet sleeves in each flow guide cavity zone increases from inside to outside, which results in an increase in the amount of air sprayed from inside to outside on the same water surface, thereby effectively drying different particle size slurries, and the screw column is driven to rotate by the operation of the motor, finally realizing the movement of the telescopic sleeve in the vertical direction, thereby adjusting the height of the flow guide cavity zone and effectively guiding the air. Such a guiding method can improve the effect of slurry drying and has good overall practicability.

[0011] As a preferred scheme of the spray drying device for preparing lithium iron phosphate, a first T-shaped rod is fixedly arranged on the other side of the bottom surface of the powder collecting cover, and a limiting plate for sliding sleeve connection of the first T-shaped rod is fixedly arranged on the inner wall of the tower body.

[0012] As a preferred scheme of the spray drying device for preparing lithium iron phosphate, the device further comprises a scraping mechanism, the scraping mechanism comprising a rotating rod arranged on the inner side of the powder collecting cover and a rack rod arranged below the connecting strip; the two ends of the rotating rod are fixedly arranged on the inner wall of the powder collecting cover in a symmetrical manner, a rotating column is fixedly arranged on the bottom surface of the middle part of the rotating rod, the lower end of the rotating column is rotatably connected to the connecting strip through a rolling bearing, a toothed disc is fixedly arranged on the bottom surface of the rotating column, a rack rod is fixedly arranged on one side of the toothed disc, one end of the rack rod is fixedly connected to one end of the U-shaped strip, and the other end of the U-shaped strip is fixedly connected to the telescopic end of the air cylinder, the air cylinder is fixedly connected to the bottom surface of the connecting strip, and the rack rod is arranged along the long side of the connecting strip.

[0013] As a preferred scheme of the spray drying device for preparing lithium iron phosphate, a second T-shaped rod is slidingly connected to the closed end of the U-shaped strip, and one end of the second T-shaped rod away from the U-shaped strip is fixedly connected to the bottom surface of the connecting strip.

[0014] As a preferred scheme of the lithium iron phosphate preparation spray drying device, the dustproof disc is sleeved on the rotating column above the connecting strip, and the dustproof disc and the scraper are fixedly connected through the scraping strip, and the bottom surface of the scraping strip is attached to the top surface of the connecting strip.

[0015] In addition, the present application also provides the following technical scheme: a lithium iron phosphate preparation process using the above-mentioned lithium iron phosphate preparation spray drying device, the steps are as follows: S1: iron phosphate and lithium carbonate are mixed according to a Li / Fe ratio of 1.05, and the mixture is dosed with titanium dioxide according to a doping amount of 2500-3000 ppm, and 6% polyethylene glycol and 7% soluble starch are added to the solid components to prepare a slurry; S2: the slurry is pumped from the slurry inlet pipe into the centrifugal atomizer, and is atomized and sprayed out through the centrifugal atomizer; S3: at the same time, the heated air is introduced into the air guide ring through the air inlet pipe, and finally discharged from the air outlet holes on the air outlet sleeve; S4: the upwardly sprayed air contacts the downwardly dripping slurry to heat the slurry, and the heated and shaped powder falls into the lower end position of the tower body through the flow guide cavity; S5: the powder and the gas are discharged into the cyclone separator through the discharge pipe, and the cyclone separator realizes the separation of solid and gas; S6: the separated and collected powder is sintered at 750-800°C for 6-10h, and finally the sintered material is crushed to obtain the lithium iron phosphate finished product. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor. Among them: Figure 1 It is a schematic diagram of the overall structure of the lithium iron phosphate preparation spray drying device in the present application.

[0017] Figure 2 It is a schematic diagram of the overall structure of the lithium iron phosphate preparation spray drying device in the present application. Figure 1 Structure in the vertical direction.

[0018] Figure 3 It is another sectional view of the structure in the vertical direction. Figure 1 Structure in the vertical direction.

[0019] Figure 4 It is a schematic diagram of the cooperation of the air injection flow guide mechanism and the scraping mechanism in the present application.

[0020] Figure 5 For the invention Figure 4 Schematic diagram of the bottom of the structure.

[0021] Figure 6 For the invention Figure 4 Exploded view of the structure.

[0022] Figure 7 Schematic diagram of the overall structure of the plurality of gas guide ring connectors in the invention.

[0023] Figure 8 For the invention Figure 7 Sectional view of the structure in the vertical direction.

[0024] Figure 9 Schematic diagram of the cooperation of the material scraping mechanism, telescopic sleeve and powder collecting cover in the invention. DETAILED DESCRIPTION

[0025] In order to make the above objectives, features and advantages of the invention more obvious and easy to understand, the specific embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0026] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the scope of the present invention, which will be apparent to one skilled in the art, and it is therefore intended that the present invention not be limited to the embodiments disclosed for purposes of exemplification.

[0027] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the invention. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment that excludes other embodiments.

[0028] Thirdly, the invention is described in detail in conjunction with the schematic diagram, and in the detailed description of the embodiments of the invention, the sectional view of the device structure will be partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the invention herein. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual manufacture. Embodiment 1

[0029] Referring to Figure 1 , Figure 2 and Figure 3For the first embodiment of the present application, the embodiment provides a spray drying device for preparing lithium iron phosphate. In use, slurry enters a centrifugal atomizer 101 at the upper end of a tower body 100 for atomization and spraying. Heated air flows from bottom to top through a gas guiding mechanism 200 to dry the atomized slurry. The dried lithium iron phosphate is discharged from the lower end of the tower body 100.

[0030] Specifically, the spray drying device comprises the tower body 100, the centrifugal atomizer 101 is embedded and fixed on the top surface of the tower body 100. The centrifugal atomizer 101 mainly sprays slurry by centrifugal force to achieve atomization. The top surface of the centrifugal atomizer 101 is fixed with a slurry inlet pipe 101a. The other end of the slurry inlet pipe 101a is connected with a storage tank or a stirring tank and cooperates with a delivery pump. The bottom surface of the tower body 100 is fixed with a discharge pipe 102 for discharging dried powder and gas. The other end of the discharge pipe 102 is connected with a cyclone separator which can realize solid-gas separation. The gas guiding mechanism 200 is arranged in the tower body 100 and comprises a gas guiding ring 201, a separation sleeve 202 and an extension sleeve 203.

[0031] Details are shown in Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 A plurality of separation sleeves 202 are arranged in concentric array from inside to outside. The bottom surface of the separation sleeve 202 is fixedly connected with the gas guiding ring 201 by bolts. The inner and outer walls of the separation sleeve 202 are connected with the gas outlet sleeve 201a at the lower end of the same gas guiding ring 201. The outermost gas guiding ring 201 is provided with the gas outlet sleeve 201a on one side of the inner wall of the separation sleeve 202. The outer wall of the outermost gas guiding ring 201 is fixedly provided with the connecting plate 201b. The connecting plate 201b is fixedly connected with the outermost separation sleeve 202 by bolts. The connecting plate 201b is fixedly connected with the connecting plate 103 on the inner wall of the tower body 100 by bolts, so as to realize detachable connection between the gas guiding mechanism 200 and the tower body 100. The connecting body of the air guide ring 201 and the air outlet sleeve 201a is provided with flow cavities 201e, and the adjacent flow cavities 201e are connected through a plurality of communication pipes 201d arranged in the circumferential direction, the upper end of the air outlet sleeve 201a is provided with a first inclined surface 201a-1, and a plurality of air outlet holes 201a-2 communicating with the flow cavities 201e are arranged in the circumferential direction on the first inclined surface 201a-1, the inner side of the outermost separation sleeve 202 is a flow guide cavity, and the flow guide cavity is divided into a plurality of flow guide cavity areas by the plurality of air outlet sleeves 201a, the number of air outlet holes 201a-2 on the plurality of air outlet sleeves 201a in the same flow guide cavity area is equal, and the number of air outlet holes 201a-2 on the air outlet sleeves 201a in each flow guide cavity area from the inside to the outside is increased, so that the amount of gas sprayed from the inside to the outside is increased; the outer wall of the outermost air guide ring 201 is fixedly provided with a gas gathering plate 201c communicating with the flow cavities 201e, and the bottom surface of the gas gathering plate 201c is fixedly provided with an air inlet pipe 201c-1, the free end of the air inlet pipe 201c-1 extends to the outside of the tower body 100, the free end of the air inlet pipe 201c-1 is connected with the air blower, and the heating device is used to heat the air. In use, the heated air enters the gas gathering plate 201c through the air inlet pipe 201c-1, and cooperates with the communication pipe 201d to realize that the air enters each flow cavity 201e and is finally sprayed from the air outlet holes 201a-2 on the air outlet sleeve 201a.

[0032] In addition, it should be noted that the device also includes a controller (not shown in the figure) for controlling each electrical element, and the controller is arranged at a position convenient for the operator to operate. Embodiment 2

[0033] Referring to Figure 3 , Figure 4 , Figure 5 and Figure 6 , this is the second embodiment of the application, which is based on the previous embodiment, and the difference is that in order to effectively dry the atomized slurry of different sizes, the height of the flow guide cavity area for slurry flow is adaptively adjusted, so as to facilitate the full contact of hot air and slurry.

[0034] Specifically, the top surface of the partition sleeve 202 is provided with an expansion slot 202a for slidingly sleeving the expansion sleeve 203, and the top surface of the expansion sleeve 203 is fixedly provided with an end ring 203a, and a plurality of end rings 203a are connected and fixed through a connecting strip 203b arranged along the radial direction of the end ring 203a; the top surface of the outermost end ring 203a is fixedly provided with a powder collecting cover 204 which is attached to the inner wall of the tower body 100, and the design of the powder collecting cover 204 can collect powders with smaller particle sizes, and the bottom surface of the powder collecting cover 204 is fixedly provided with an L-shaped plate 204c, and a screw column 204a is screw-coupled to the horizontal plate at the lower end of the L-shaped plate 204c, the lower end of the screw column 204a is fitted into the output end of a motor 204a-1, and the motor 204a-1 is fixedly connected to the inner wall of the tower body 100; the bottom surface of the other side of the powder collecting cover 204 opposite to the L-shaped plate 204c is fixedly provided with a first T-shaped rod 204b, and the inner wall of the tower body 100 is fixedly provided with a limiting plate 104 for slidingly sleeving the first T-shaped rod 204b, so as to limit and guide the movement of the powder collecting cover 204. When the above arrangement is used, the rotation of the screw column 204a can be realized through the working of the motor 204a-1, because the screw column 204a and the L-shaped plate 204c are screw-coupled, and under the rotation of the screw column 204a, the L-shaped plate 204c can drive the powder collecting cover 204 to move in the vertical direction, and finally the expansion sleeve 203 can move and adjust in the vertical direction relative to the expansion slot 202a, so as to adjust the height of the flow guiding cavity area.

[0035] Further, the inner wall of the upper end of the powder collecting cover 204 is provided with a second inclined surface, so as to avoid the accumulation of powders on the top surface of the powder collecting cover 204. Embodiment 3

[0036] Referring to Figure 4 , Figure 6 and Figure 9 , this is the third embodiment of the present application, which is based on the previous embodiment, and the difference is that in order to avoid the problem that powders adhere to the inner wall of the powder collecting cover 204, thus making it inconvenient for the staff to clean effectively, a scraping mechanism 300 is proposed.

[0037] Specifically, the scraping mechanism 300 comprises a rotating rod 301 arranged inside the dust collecting cover 204 and a rack rod 302 arranged below the connecting strip 203b; the two ends of the rotating rod 301 are symmetrically fixed with scraping plates 301a abutting against the inner wall of the dust collecting cover 204, the middle bottom surface of the rotating rod 301 is fixed with a rotating column 301b, the lower end of the rotating column 301b is rotatably sleeved on the connecting strip 203b through a rolling bearing, the bottom surface of the rotating column 301b is fixed with a gear disc 301d, one side of the gear disc 301d is engaged with the rack rod 302, one end of the rack rod 302 is fixedly connected with one end of a U-shaped strip 302a, the other end of the U-shaped strip 302a is fixedly connected with the telescopic end of a gas cylinder 302b, the gas cylinder 302b is fixedly connected on the bottom surface of the connecting strip 203b, and the rack rod 302 is arranged along the long side direction of the connecting strip 203b; a second T-shaped rod 302c is slidably sleeved on the closed end of the U-shaped strip 302a, and the end of the second T-shaped rod 302c away from the U-shaped strip 302a is fixedly connected on the bottom surface of the connecting strip 203b, and the second T-shaped rod 302c can limit and guide the movement of the U-shaped strip 302a; When the above arrangement is used, the telescopic movement of the U-shaped strip 302a and the rack rod 302 can be realized through the telescopic movement of the gas cylinder 302b, and finally the gear disc 301d drives the rotating column 301b to rotate forward and backward, and the rotating rod 301 drives the scraping plates 301a to rotate forward and backward, so as to scrape off the dust collected on the dust collecting cover 204 and avoid the accumulation of dust on the dust collecting cover 204.

[0038] Further, the dustproof disc 301b-1 is fixedly sleeved on the rotating column 301b above the connecting strip 203b, the dustproof disc 301b-1 can avoid the accumulation of dust in the rolling bearing, the scraping strip 301c is fixedly connected between the dustproof disc 301b-1 and the scraping plate 301a, the bottom surface of the scraping strip 301c abuts against the top surface of the connecting strip 203b, and the scraping strip 301c can scrape off the dust accumulated on the connecting strip 203b. Embodiment 4

[0039] This embodiment is the fourth embodiment of the present application, which provides a lithium iron phosphate preparation process, and the steps are as follows: S1: Iron phosphate and lithium carbonate are mixed according to the ratio of Li / Fe of 1.05, the mixture is dosed with titanium dioxide according to the doping amount of 2500-3000 ppm, 6% of polyethylene glycol and 7% of soluble starch are put into the solid components, and the slurry is prepared; S2: The slurry is pumped into the centrifugal atomizer 101 from the slurry inlet pipe 101a, and is sprayed out through the centrifugal atomizer 101; S3: At the same time, the air after heating is blown into the air guide ring 201 through the air inlet pipe 201c-1, and finally discharged from the air outlet hole 201a-2 on the air outlet sleeve 201a; S4: The upwardly sprayed air contacts the downwardly dripping slurry, and the slurry is heated. The heated and shaped powder falls into the lower end position of the tower body 100 through the flow guide cavity; S5: The powder and the gas are discharged into the cyclone separator through the discharge pipe 102, and the cyclone separator realizes the separation of solid and gas; S6: The separated and collected powder is sintered at 750-800℃ for 6-10h, and finally the sintered material is crushed to obtain the finished lithium iron phosphate.

[0040] In addition, it should be noted that the components not described in detail herein are prior art.

[0041] Importantly, it should be noted that the construction and arrangement of the application shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications can be made to the embodiments without departing from the novel teachings and the advantages that are described in this application (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements or positions can be altered or varied. Other substitutions, modifications, changes, and omissions can also be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to the specific embodiments described herein, but extends to all modifications that retain at least some of the novel teachings and advantages described herein.

[0042] Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation can not be described (i.e., those unrelated to the presently contemplated best mode of carrying out the application, or those unrelated to enabling the application).

[0043] It is to be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions can be made. Such development efforts can inevitably lead to a number of substitutions, modifications, changes, and omissions of features not specifically described herein, but which are within the scope of the present application. Accordingly, all such modifications are intended to be included within the scope of the present application.

[0044] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A spray drying device for preparing lithium iron phosphate, characterized in that: include, A tower body (100), wherein a centrifugal atomizer (101) is embedded and fixedly provided on the top surface of the tower body (100); and An air jet guide mechanism (200) is provided in the tower body (100), comprising an air guide ring (201), a separation sleeve (202), and a telescopic sleeve (203); a plurality of separation sleeves (202) are arranged in a concentric array from the inside out; an air guide ring (201) is fixedly connected to the bottom surface of the separation sleeve (202) by bolts; an air outlet sleeve (201a) is provided at the lower ends of the inner and outer walls of the separation sleeve (202), the lower ends of which are connected to the top surface of the same air guide ring (201); and the air outlet sleeve (201a) is provided on the outermost air guide ring (201) only on one side of the inner wall of the separation sleeve (202); A flow cavity (201e) is provided in the connecting body of the air guide ring (201) and the air outlet sleeve (201a), and adjacent flow cavities (201e) are connected via a plurality of connecting pipes (201d) arranged in a circumferential array. The upper end of the air outlet sleeve (201a) is provided with a first inclined surface (201a-1), and air outlet holes (201a-2) communicating with the flow cavity (201e) are arranged in a circumferential array on the first inclined surface (201a-1). The inner side of the outermost separation sleeve (202) is a flow guide cavity, and the plurality of air outlet sleeves (201a) divide the flow guide cavity into a plurality of flow guide cavity areas. The number of air outlet holes (201a-2) on the plurality of air outlet sleeves (201a) in the same flow guide cavity area is equal, and the number of air outlet holes (201a-2) on the air outlet sleeves (201a) in each flow guide cavity area increases from the inside to the outside. An air collecting plate (201c) in communication with the circulation cavity (201e) is fixedly provided on the outer side wall of the outermost air guide ring (201), and an air inlet pipe (201c-1) is fixedly provided on the bottom surface of the air collecting plate (201c), wherein the free end of the air inlet pipe (201c-1) extends to the outside of the tower body (100).

2. A spray drying device for preparing lithium iron phosphate according to claim 1, characterized in that: A slurry inlet pipe (101a) is fixedly provided on the top surface of the centrifugal atomizer (101), and a discharge pipe (102) is fixedly provided on the bottom surface of the tower body (100).

3. A spray drying device for preparing lithium iron phosphate according to claim 2, characterized in that: Connecting pieces (201b) are symmetrically fixed on the outer wall of the outermost air guide ring (201), and the connecting pieces (201b) are fixedly connected to the outermost separation sleeve (202) via bolts. The connecting pieces (201b) are also fixedly connected to a connecting plate (103) fixed on the inner wall of the tower body (100) via bolts.

4. A spray drying device for preparing lithium iron phosphate according to claim 1 or 3, characterized in that: A telescopic groove (202a) for the telescopic sleeve (203) to be slidably sleeved is provided on the top surface of the separation sleeve (202), and an end ring (203a) is fixedly provided on the top surface of the telescopic sleeve (203), and a plurality of the end rings (203a) are connected and fixed by a connecting strip (203b) arranged along the radial direction of the end ring (203a); A powder collecting cover (204) is fixedly provided on the top surface of the outermost end ring (203a) along the circumferential direction and is in contact with the inner wall of the tower body (100); an L-shaped plate (204c) is fixedly provided on one side of the bottom surface of the powder collecting cover (204); and a screw column (204a) is spirally sleeved on the horizontal plate at the lower end of the L-shaped plate (204c); the lower end of the screw column (204a) is embedded in the output end of the motor (204a-1), and the motor (204a-1) is fixedly connected to the inner wall of the tower body (100).

5. A spray drying device for preparing lithium iron phosphate according to claim 4, characterized in that: A first T-shaped rod (204b) is fixedly provided on the bottom surface of the other side of the powder collecting cover (204) provided with the L-shaped plate (204c), and a limiting plate (104) for slidingly sleeve engagement with the first T-shaped rod (204b) is fixedly provided on the inner wall of the tower body (100); The inner wall of the upper end of the powder collecting cover (204) is provided as a second inclined surface.

6. A spray drying device for preparing lithium iron phosphate according to claim 5, characterized in that: It also includes a scraping mechanism (300), the scraping mechanism (300) including a rotating rod (301) arranged inside the powder collecting cover (204) and a rack rod (302) arranged below the connecting bar (203b); Scrapers (301a) that are symmetrically fixed to the two ends of the rotating rod (301) and are in contact with the inner wall of the powder collecting cover (204) are fixedly provided. A rotating column (301b) is fixedly provided on the bottom surface of the middle portion of the rotating rod (301), and the lower end of the rotating column (301b) is rotatably sleeved on the connecting bar (203b) via a rolling bearing. A toothed disc (301d) is fixedly provided on the bottom surface of the rotating column (301b), and a rack rod (302) is meshed with one side of the toothed disc (301d). One end of the rack rod (302) is fixedly connected to one end of the U-shaped bar (302a), and the other end of the U-shaped bar (302a) is fixedly connected to the telescopic end of the cylinder (302b). The cylinder (302b) is fixedly connected to the bottom surface of the connecting bar (203b), and the rack rod (302) is arranged along the long side direction of the connecting bar (203b).

7. A spray drying device for preparing lithium iron phosphate according to claim 6, characterized in that: A second T-shaped rod (302c) is slidably sleeved on the closed end of the U-shaped bar (302a), and one end of the second T-shaped rod (302c) away from the U-shaped bar (302a) is fixedly connected to the bottom surface of the connecting bar (203b).

8. The spray drying device for preparing lithium iron phosphate according to claim 6, characterized in that: A dustproof disc (301b-1) is fixedly sleeved on the rotating column (301b) above the connecting bar (203b), and the dustproof disc (301b-1) and the scraper (301a) are fixedly connected via a scraping bar (301c), with the bottom surface of the scraping bar (301c) affixed to the top surface of the connecting bar (203b).

9. A process for preparing lithium iron phosphate, characterized in that: Using the spray drying device for preparing lithium iron phosphate according to any one of claims 6 to 8, the steps are as follows: S1: Iron phosphate and lithium carbonate are mixed at a Li / Fe ratio of 1.05, the mixture is doped with titanium dioxide at a doping amount of 2500-3000 ppm, 6% polyethylene glycol and 7% soluble starch are added to the solid component to prepare a slurry; S2: pumping the slurry from the slurry inlet pipe (101a) into the centrifugal atomizer (101) and atomizing and spraying the slurry out through the centrifugal atomizer (101); S3: At the same time, the heated air is blown into the air guide ring (201) through the air inlet pipe (201c-1), and is finally discharged from the air outlet hole (201a-2) on the air outlet sleeve (201a); S4: the upwardly ejected air contacts the downwardly dripping slurry, heating the slurry, and the heated and formed powder falls into the lower end of the tower body (100) through the guide cavity; S5: The powder and gas are discharged into the cyclone separator through the discharge pipe (102), and the cyclone separator realizes the separation of solid and gas; S6: The separated and collected powder is sintered at 750° C. to 800° C. for 6 h to 10 h, and finally the sintered material is crushed to obtain a finished lithium iron phosphate product.

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