Fluidization crystal transformation furnace and fluidization crystal transformation device

Abstract

The utility model discloses a fluidization crystal transformation furnace and a fluidization crystal transformation device. The technical problem that in the prior art, metal impurities are likely to be introduced into anhydrous iron phosphate when a rotary kiln is adopted for calcining iron phosphate hydrate to prepare battery-grade anhydrous iron phosphate is solved. The fluidization crystal transformation furnace comprises a furnace body, and a non-metal material layer is arranged on the inner wall of the furnace body; a gas distribution plate is arranged at the lower part of the furnace body; the bottom end of the furnace body is connected with a hot air inlet pipe, the top end of the furnace body is connected with a hot air outlet pipe, and the air inlet direction of the hot air inlet pipe right faces the gas distribution plate. According to the fluidization crystal transformation furnace and the fluidization crystal transformation device, metal impurities can be effectively prevented from entering the anhydrous iron phosphate in the anhydrous iron phosphate preparation process, high purity and high quality of the prepared anhydrous iron phosphate can be ensured, the quality consistency of crystal transformation products is high, and the product yield is high. And meanwhile, the device has the advantages of energy conservation, simple structure and low investment cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical equipment, in particular to a fluidized crystal transformation furnace and a fluidized crystal transformation device. BACKGROUND

[0002] With the rapid development of new energy automobile and energy storage market, the demand for lithium iron phosphate battery is continuously growing. It is predicted that by 2030, lithium iron phosphate battery will dominate the global battery market. Anhydrous iron phosphate is a core material for preparing lithium iron phosphate battery. In lithium iron phosphate battery, the purity of anhydrous iron phosphate is very strict, so it is necessary to avoid the introduction of impurities, especially metal impurities, during the preparation of anhydrous iron phosphate. If there are metal impurities in the anhydrous iron phosphate used in lithium iron phosphate battery, it will have a great influence on the performance of lithium iron phosphate battery. More seriously, there is a safety hazard that the battery may explode during use. Therefore, the purity of anhydrous iron phosphate is strictly required, and the main purpose is to ensure the high performance, long life and safety of lithium iron phosphate battery.

[0003] Anhydrous iron phosphate is obtained by removing crystal water from iron phosphate hydrate. The existing preparation of battery-grade anhydrous iron phosphate uses a rotary kiln to calcine and remove crystal water and to carry out crystal transformation reaction. However, the rotary kiln calcination has the following defects: first, during calcination, the rotary kiln rotates continuously, and the metal parts inside the rotary kiln repeatedly rub with iron phosphate hydrate particles or amorphous iron phosphate, which easily introduces metal impurities into anhydrous iron phosphate; second, the rotary kiln uses the combined action of heat exchange and heat convection to heat iron phosphate hydrate particles or amorphous iron phosphate, which has low heat transfer efficiency, large heat loss and high energy consumption; third, the rotary kiln cannot be provided with a waste heat recovery device, resulting in large heat energy loss; fourth, when the rotary kiln is working, the weight of the material is much smaller than the weight of the kiln body, so the power consumption for providing kinetic energy is mainly used for rotating the kiln body rather than the material, resulting in large power consumption; fifth, the investment in rotary kiln is large. CONTENT OF THE INVENTION

[0004] The purpose of the present application is to provide a fluidized crystal transformation furnace and a fluidized crystal transformation device to solve the technical problem that the existing technology uses a rotary kiln to calcine iron phosphate hydrate to prepare battery-grade anhydrous iron phosphate, which easily introduces metal impurities into anhydrous iron phosphate. The preferred technical solutions in the many technical solutions provided by the present application can produce many technical effects, which are described in detail below.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] In a first aspect, the application provides a fluidized crystal transformation furnace, comprising a furnace body, an inner wall of the furnace body being provided with a non-metallic material layer; a lower portion of the furnace body being provided with a gas distribution plate of non-metallic material; a bottom end of the furnace body being connected with a hot air inlet pipe, a top end of the furnace body being connected with a hot air outlet pipe, and an air inlet direction of the hot air inlet pipe being opposite to the gas distribution plate.

[0007] Optionally or preferably, the non-metallic material layer comprises a quartz glass layer.

[0008] Optionally or preferably, the furnace body comprises a heat-insulating furnace body and a furnace shell sleeved outside the heat-insulating furnace body.

[0009] Optionally or preferably, an outer wall and / or an inner wall of the heat-insulating furnace body is coated with a magnesium oxide layer.

[0010] Optionally or preferably, the heat-insulating furnace body is made of magnesium oxide.

[0011] Optionally or preferably, the furnace body further comprises a heat-insulating layer sleeved outside the heat-insulating furnace body, and the furnace shell is sleeved outside the heat-insulating layer.

[0012] Optionally or preferably, the heat-insulating layer comprises a heat-insulating asbestos layer and / or a rock wool layer.

[0013] Optionally or preferably, the hot air outlet pipe is a double-layer pipe comprising an inner pipe and an outer pipe sleeved outside the inner pipe, a flow channel of heat exchange fluid being formed between the inner pipe and the outer pipe, one end of the inner pipe being connected with a hot air outlet of the furnace body, the other end of the inner pipe being an outer discharge end, the outer pipe having a first closed end and a second closed end, the first closed end of the outer pipe being an end away from the furnace body, the second closed end of the outer pipe being an end close to the furnace body, and the first closed end and the second closed end being respectively connected with a liquid inlet pipe of heat exchange fluid and a liquid outlet pipe of heat exchange fluid.

[0014] Optionally or preferably, the hot air outlet pipe is a vertical pipe, and the inner pipe of the hot air outlet pipe is a corrugated pipe.

[0015] In a second aspect, the application provides a fluidized crystal transformation device, comprising the above fluidized crystal transformation furnace.

[0016] Based on the above technical solutions, the embodiments of the application can at least produce the following technical effects:

[0017] The fluidized transformation furnace provided by the application can be used for preparing battery-grade anhydrous iron phosphate. The process for preparing anhydrous iron phosphate by using the fluidized transformation furnace in the application comprises: ① a crystallization water removal stage: at a temperature of 200-300 DEG C, the crystallization water of iron phosphate hydrate is removed to generate amorphous iron phosphate; ② a transformation stage: at 600-700 DEG C, the iron phosphate undergoes a transformation reaction to finally form anhydrous iron phosphate. When the fluidized transformation furnace in the application is used to prepare anhydrous iron phosphate, iron phosphate hydrate particles (iron phosphate dihydrate) are first added into the furnace body, and then the pressurized high-temperature gas enters from the hot air inlet pipe at the bottom, and is uniformly distributed by the gas distribution plate and then blown upwards. The gas distribution plate is arranged to uniformly distribute the gas into the furnace body, thereby avoiding the problems of excessively high or low local gas concentration, ensuring the stability and efficiency of the reaction process, and the hot air uniformly distributed by the gas distribution plate makes the iron phosphate hydrate particles or amorphous iron phosphate suspended and flow, forming a fluidized state similar to liquid. This state helps the iron phosphate hydrate particles or amorphous iron phosphate to fully contact with the blown hot air, realizing the heat transfer process. The fluidized transformation furnace provided by the application has the following advantages:

[0018] (1) In the process of removing the crystallization water of iron phosphate hydrate and realizing the transformation, metal impurities are effectively avoided. In the whole process of preparing anhydrous iron phosphate, the iron phosphate hydrate particles or amorphous iron phosphate will contact with the inner wall of the fluidized transformation furnace body and also undergo a certain friction. However, since the inner wall of the fluidized transformation furnace body is provided with a non-metal material layer, metal impurities can be effectively isolated during the preparation of anhydrous iron phosphate, and the metal impurities can be effectively prevented from entering the anhydrous iron phosphate, thereby ensuring the high purity and high quality of the prepared anhydrous iron phosphate, and further ensuring the high performance, long service life and safety of the lithium iron phosphate battery;

[0019] (2) In the process of removing the crystallization water of iron phosphate hydrate and realizing the transformation, the iron phosphate hydrate particles (iron phosphate dihydrate) are always in a flowing state, and the gas distribution plate is arranged to uniformly distribute the gas into the furnace body, thereby ensuring the uniformity of the heating of the iron phosphate hydrate particles (iron phosphate dihydrate) and greatly improving the quality consistency of the transformation product;

[0020] (3) The fluidized transformation furnace provided by the application does not need to rotate during use, and compared with the rotary kiln, the use of the fluidized transformation furnace greatly saves the use of electric energy since the heavy kiln body does not need to rotate;

[0021] (4) Compared with the existing rotary kiln for removing the crystallization water and realizing the transformation, the fluidized transformation furnace provided by the application also has the advantages of simple structure and low investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative labor.

[0023] Figure 1 is a structural schematic diagram of the embodiment 1 of the present application;

[0024] Figure 2 is a sectional view of A-A in Figure 1

[0025] Figure 3 is an enlarged schematic diagram of B part in Figure 2

[0026] Figure 4 is an enlarged schematic diagram of C part in Figure 2

[0027] is a schematic diagram of installation of the feeding pipe and the discharging pipe in one of the implementation manners in the embodiment 1 of the present application; Figure 5

[0028] is a structural schematic diagram of the embodiment 2 of the present application. Figure 6 In the drawings:

[0029] 10 - furnace body; 101 - heat-insulated furnace body; 102 - furnace body shell; 103 - heat-insulating layer; 104 - non-metallic material layer;

[0030] 20 - hot air inlet pipe;

[0031] 30 - hot air outlet pipe; 301 - inner pipe; 302 - outer pipe; 3021 - first closed end; 3022 - second closed end; 3023 - liquid inlet pipe; 3024 - liquid outlet pipe; 303 - flow passage;

[0032] 40 - air feeding device;

[0033] 50 - heating device;

[0034] 60 - top cover; 601 - cover body; 602 - protective shell;

[0035] 70 - feeding pipe;

[0036] 80 - discharging pipe;

[0037] 90 - gas distribution plate.

[0038] DETAILED DESCRIPTION

[0039] ​​​In order to make the purposes, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0040] Embodiment 1

[0041] Please see Figures 1-4 The present application provides a fluidized crystal transformation furnace, comprising a furnace body 10, the inner wall of the furnace body 10 is provided with a non-metallic material layer 104; the lower part of the furnace body 10 is provided with a gas distribution plate 90 made of non-metallic material; the bottom end of the furnace body 10 is connected with a hot air inlet pipe 20, the top end of the furnace body 10 is connected with a hot air outlet pipe 30, the air inlet direction of the hot air inlet pipe 20 is opposite to the gas distribution plate 90.

[0042] The fluidized transformation furnace provided by the application is used for preparing battery-grade anhydrous iron phosphate. The process for preparing anhydrous iron phosphate by using the fluidized transformation furnace in the application comprises: ① a crystallization water removal stage: at a temperature of 200-300 DEG C, the crystallization water of iron phosphate hydrate is removed to generate amorphous iron phosphate; ② a transformation stage: at 600-700 DEG C, the iron phosphate undergoes a transformation reaction to finally form anhydrous iron phosphate. When the fluidized transformation furnace in the application is used to prepare anhydrous iron phosphate, iron phosphate hydrate particles are first added into the furnace body 10, the pressurized high-temperature gas enters from the hot air inlet pipe 20 at the bottom, and then is uniformly distributed by the gas distribution plate 90 and blown upwards. The gas distribution plate 90 is arranged to uniformly distribute the gas into the furnace body 10, thereby avoiding the problems of excessively high or low local gas concentration, ensuring the stability and efficiency of the reaction process, and the hot air uniformly distributed by the gas distribution plate 90 makes the iron phosphate hydrate particles or amorphous iron phosphate suspended and flow, forming a fluidized state similar to a liquid. This state helps the iron phosphate hydrate particles or amorphous iron phosphate to fully contact with the blown hot air, realizing the heat transfer process. The fluidized transformation furnace provided by the application has the following advantages: (1) in the process of removing the crystallization water of iron phosphate hydrate and realizing the transformation, metal impurities are effectively avoided. In the whole process of preparing anhydrous iron phosphate, the iron phosphate hydrate particles or amorphous iron phosphate will contact with the inner wall of the fluidized transformation furnace body 10 and also undergo a certain friction. However, since the inner wall of the fluidized transformation furnace body 10 is provided with a non-metal material layer 104, metal impurities can be effectively isolated in the process of preparing anhydrous iron phosphate, which can effectively avoid the metal impurities entering the anhydrous iron phosphate, can ensure the high purity and high quality of the prepared anhydrous iron phosphate, and further can ensure the high performance, long service life and safety of the lithium iron phosphate battery; (2) in the process of removing the crystallization water of iron phosphate hydrate and realizing the transformation, the iron phosphate hydrate particles (ferrous phosphate dihydrate) are always in a flowing state, and the arrangement of the gas distribution plate 90 can uniformly distribute the gas into the furnace body 10, thereby ensuring the uniformity of the heating of the iron phosphate hydrate particles (ferrous phosphate dihydrate) and greatly improving the quality consistency of the transformed product; (3) the fluidized transformation furnace provided by the application does not need to rotate in the process of use, and compared with the rotary kiln, since the heavy kiln body does not need to rotate, the use of electric energy is greatly saved; (4) compared with the existing rotary kiln for removing the crystallization water and realizing the transformation, the fluidized transformation furnace provided by the application also has the advantages of simple structure and low investment cost.

[0043] In some embodiments, the non-metallic material layer 104 is a quartz glass layer. It can be understood that the non-metallic material layer 104 is provided to isolate metal impurities and prevent metal impurities from entering the anhydrous iron phosphate. The quartz glass layer is used because quartz glass has good wear resistance, high temperature resistance, corrosion resistance and aging resistance, and has a low thermal expansion coefficient, which is very suitable for long-term stable removal of crystal water and crystal transformation reaction of iron phosphate hydrate. Of course, the material of the non-metallic material layer 104 is not limited to the material disclosed in the embodiments of the present application, as long as it has good wear resistance, high temperature resistance, corrosion resistance and aging resistance, and has a low thermal expansion coefficient, and can long-term stable removal of crystal water and crystal transformation reaction of iron phosphate hydrate.

[0044] In some embodiments, the material of the gas distribution plate 90 is quartz glass. It can be understood that in order to avoid metal impurities entering the anhydrous iron phosphate as much as possible, the gas distribution plate 90 is also made of non-metallic material. Of course, the material of the non-metallic material layer 104 is not limited to the material disclosed in the embodiments of the present application, as long as it has good wear resistance, high temperature resistance, corrosion resistance and aging resistance, and has a low thermal expansion coefficient, and can long-term stable removal of crystal water and crystal transformation reaction of iron phosphate hydrate.

[0045] In some embodiments, the furnace body 10 includes a heat-insulating furnace body 101 and a furnace shell 102 sleeved outside the heat-insulating furnace body 101. It can be understood that the heat-insulating furnace body 101 is used to provide a reaction space for removal of crystal water and crystal transformation reaction, and to insulate and keep warm during the removal of crystal water and crystal transformation reaction; and the furnace shell 102 is used to protect the internal structure.

[0046] In some embodiments, the furnace shell 102 is made of metal material, such as stainless steel. Of course, the material of the furnace shell 102 is not limited by the embodiments of the present application, and other materials can also be used.

[0047] In some embodiments, the outer wall and / or inner wall of the heat-insulating furnace body 101 is coated with a magnesium oxide layer. It can be understood that magnesium oxide has a high specific heat capacity, and the magnesium oxide layer coated on the outer wall and / or inner wall of the heat-insulating furnace body 101 can play a good heat preservation role, thereby better playing a heat preservation role and heating reaction of the iron phosphate, thereby improving the heat transfer efficiency, reducing the heat loss and reducing the energy consumption.

[0048] In some embodiments, the material of the heat insulation furnace body 101 is magnesia. Since the specific heat capacity of magnesia is high, the heat insulation furnace body 101 made of magnesia can have good heat preservation effect, thereby better achieving the heat preservation and heating reaction of the iron phosphate, improving the heat transfer efficiency, reducing the heat loss, and reducing the energy consumption.

[0049] In some embodiments, the furnace body 10 further comprises a heat preservation layer 103 sleeved outside the heat insulation furnace body 101, and the furnace shell 102 is sleeved outside the heat preservation layer 103. It can be understood that the heat preservation layer 103 is arranged to further improve the heat preservation effect of the furnace body 10, further improve the heat transfer efficiency, reduce the heat loss, and further reduce the energy consumption.

[0050] In some embodiments, the heat preservation layer 103 comprises a heat preservation asbestos layer and / or a rock wool layer. It can be understood that the heat preservation layer 103 comprises a heat preservation asbestos layer or a rock wool layer; or the heat preservation layer 103 comprises a heat preservation asbestos layer and a rock wool layer; or the heat preservation asbestos layer and the rock wool layer can be arranged in multiple layers. Of course, the specific structure of the heat preservation layer 103 is not limited by the embodiments of the present application, and other heat preservation structures can also be used as the heat preservation layer 103 as long as they can have heat preservation effect. In addition, the material of the heat preservation layer 103 is not limited by the embodiments of the present application, and other materials that can have heat preservation effect can also be used as the heat preservation layer 103.

[0051] In some embodiments, the hot air outlet pipe 30 is a double-layer pipe, including an inner pipe 301 and an outer pipe 302 sleeved outside the inner pipe 301, and a flow channel 303 of heat exchange fluid between the inner pipe 301 and the outer pipe 302. One end of the inner pipe 301 is connected with the hot air outlet of the furnace body 10, and the other end of the inner pipe 301 is an outer discharge end. The outer pipe 302 has a first closed end 3021 and a second closed end 3022. The first closed end 3021 of the outer pipe 302 is an end away from the furnace body 10, and the second closed end 3022 of the outer pipe 302 is an end close to the furnace body 10. The first closed end 3021 and the second closed end 3022 are respectively connected with a liquid inlet pipe 3023 of heat exchange fluid and a liquid outlet pipe 3024 of heat exchange fluid. It can be understood that the temperature of the gas discharged from the hot air outlet pipe 30 is still very high, and if it is directly discharged, there is a certain loss of heat energy. Therefore, the hot air outlet pipe 30 is arranged as a double-layer pipe, and heat exchange fluid is introduced into the flow channel 303 between the inner pipe 301 and the outer pipe 302 to absorb the heat in the gas discharged from the hot air outlet pipe 30 and utilize it in other processes, such as the drying process of ferrous phosphate dihydrate. The ferrous phosphate dihydrate is in a fluid state before drying, and in order to facilitate subsequent removal of crystal water and crystal transformation reaction, it is necessary to first dry the ferrous phosphate dihydrate in a fluid state. The heat in the gas discharged from the hot air outlet pipe 30 at this time can be used for drying the ferrous phosphate dihydrate into a granular state. This drying process utilizes the heat in the gas discharged from the hot air outlet pipe 30 twice, recovers and utilizes the waste heat, can further reduce heat loss, greatly saves heat energy, and further reduces energy consumption and production cost.

[0052] In some embodiments, the hot air outlet pipe 30 is a vertical pipe, and the inner pipe 301 of the hot air outlet pipe 30 is a corrugated pipe. It can be understood that in the process of removing crystal water and crystal transformation reaction by high-pressure hot air, the hot air can carry part of the material out of the furnace body 10 and into the hot air outlet pipe 30. The inner pipe 301 is arranged as a corrugated pipe, and the pipe wall of the inner pipe 301 is corrugated. When the hot air is resisted by the pipe wall of the inner pipe 301, the material carried out by the hot air can be stopped, and the material has the opportunity to fall back into the furnace body 10 again.

[0053] In some embodiments, the fluidized crystal transformation furnace further includes a top cover 60 matched with the furnace body 10. The top cover 60 includes a cover body 601 and a protective shell 602 arranged outside the cover body 601. The hot air outlet pipe 30 is connected to the top cover 60. The top cover 60 and the furnace body 10 can be fixed by welding, such as welding between the protective shell 602 and the furnace shell 102, or can be fixed by other detachable connection methods.

[0054] Please refer to Figure 5In some embodiments, the furnace body 10 is provided with a feeding pipe 70 and a discharging pipe 80, both of which are arranged on the side wall of the furnace body 10. For the discharging mode, a suction discharging device can be connected to the discharging pipe 80 to discharge the anhydrous ferric phosphate from the furnace body 10. Of course, the discharging mode is not limited by the embodiments of the present application, for example, bottom overturning discharging, top discharging and the like can also be used.

[0055] In some embodiments, the feeding pipe 70 is multiple and uniformly arranged around the circumference of the furnace body 10; the angle between the feeding pipe 70 and the outer wall of the furnace body 10 is 15°-75°; by multi-point oblique feeding, the entering ferric phosphate hydrate is distributed as uniformly as possible, the uniformity of the material distribution is improved, the non-uniformity of the material residence time distribution is reduced, and the reaction is more beneficial to proceed. Of course, the feeding mode is not limited by the embodiments of the present application, for example, spiral feeder feeding and the like can also be used.

[0056] In some embodiments, the angle between the feeding pipe 70 and the outer wall of the furnace body 10 is 30°-60°.

[0057] The working process of preparing anhydrous ferric phosphate by using the fluidized crystal transformation furnace in the present application is as follows:

[0058] First, the ferric phosphate hydrate particles are added into the furnace body 10, the pressurized high-temperature gas enters from the hot air inlet pipe 20 at the bottom, then is uniformly distributed by the gas distribution plate 90 and is blown upward to remove the crystallization water and to perform the crystal transformation reaction; after the crystal transformation reaction is completed, the heating is stopped, the anhydrous ferric phosphate is cooled to room temperature, the anhydrous ferric phosphate is discharged from the furnace body 10, and then subsequent processes such as screening are performed.

[0059] Embodiment 2:

[0060] Please refer to Figure 6 The present application provides a fluidized crystal transformation device, which comprises the furnace body 10 in the embodiment 1, further comprises a blowing device 40, a heating device 50 and a control device; wherein,

[0061] The air outlet of the blowing device 40 is connected with the air inlet of the heating device 50;

[0062] The air outlet of the heating device 50 is connected with the hot air inlet pipe 20 of the furnace body 10;

[0063] The blowing device 40 and the heating device 50 are respectively electrically connected with the control device. It can be understood that the blowing device 40 is used for blowing air into the furnace body 10, the heating device 50 is used for heating the air blown into the furnace body 10 to the required temperature, and the control device is used for controlling the air blowing amount and speed of the blowing device 40 and controlling the heating device 50 to heat the air to the required temperature.

[0064] In some embodiments, the air supply device 40 comprises a Roots blower, through which air supply and pressurization are performed. Of course, the structure of the air supply device 40 is not limited by the embodiments of the present application, and the air supply device 40 can also be of other structures.

[0065] In some embodiments, the control device is a PLC.

[0066] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be encompassed in the protection scope of the present application.

Claims

1. A fluidized recrystallization furnace characterized by, The furnace body (10) is provided with a non-metal material layer (104) on the inner wall; the lower part of the furnace body (10) is provided with a gas distribution plate (90) made of non-metal material; the bottom end of the furnace body (10) is connected with a hot air inlet pipe (20), and the top end of the furnace body (10) is connected with a hot air outlet pipe (30), and the air inlet direction of the hot air inlet pipe (20) is opposite to the gas distribution plate (90).

2. The fluidized crystal conversion furnace according to claim 1, wherein The non-metal material layer (104) comprises a quartz glass layer.

3. The fluidized crystal conversion furnace according to claim 1, wherein The furnace body (10) comprises a heat-insulating furnace body (101) and a furnace body shell (102) sleeved outside the heat-insulating furnace body (101).

4. The fluidized crystal conversion furnace according to claim 3, wherein The outer wall and / or the inner wall of the heat-insulating furnace body (101) is coated with a magnesium oxide layer.

5. The fluidized crystal conversion furnace according to claim 3, wherein The material of the heat-insulating furnace body (101) is magnesium oxide.

6. The fluidized crystal conversion furnace according to claim 3, wherein The furnace body (10) further comprises a heat-insulating layer (103) sleeved outside the heat-insulating furnace body (101), and the furnace body shell (102) is sleeved outside the heat-insulating layer (103).

7. The fluidized crystal conversion furnace according to claim 6, wherein The heat-insulating layer (103) comprises a heat-insulating asbestos layer and / or a rock wool layer.

8. The fluidized crystal conversion furnace of claim 1 wherein, The hot air outlet pipe (30) is a double-layer pipe, comprising an inner pipe (301) and an outer pipe (302) sleeved outside the inner pipe (301), and a flow channel (303) of heat exchange fluid is formed between the inner pipe (301) and the outer pipe (302); one end of the inner pipe (301) is connected with the hot air outlet of the furnace body (10), and the other end of the inner pipe (301) is an outer discharge end; the outer pipe (302) has a first closed end (3021) and a second closed end (3022); the first closed end (3021) of the outer pipe (302) is away from the furnace body (10), and the second closed end (3022) of the outer pipe (302) is close to the furnace body (10); the first closed end (3021) and the second closed end (3022) are respectively connected with a liquid inlet pipe (3023) of heat exchange fluid and a liquid outlet pipe (3024) of heat exchange fluid.

9. The fluidized crystal conversion furnace according to claim 8, wherein The hot air outlet pipe (30) is a vertical pipe, and the inner pipe (301) of the hot air outlet pipe (30) is a corrugated pipe.

10. A fluidized recrystallization apparatus, characterized by, The fluidized crystal transformation furnace comprises the fluidized crystal transformation furnace according to any one of claims 1-9.

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