A system for refining a transition metal compound and a method of refining a transition metal compound

Abstract

The application discloses a transition metal compound refining system and a refining method thereof, and belongs to the technical field of materials. The application provides a transition metal compound refining system, which comprises an evaporation device and a primary crystallization chamber, wherein the evaporation device and the primary crystallization chamber are communicated; the evaporation device comprises an evaporator, a gas pipe and a heating element; the gas pipe is used for introducing inert gas to carry the gas flowing out of the gas outlet of the evaporator into the primary crystallization chamber. The application further provides a refining method of the above-mentioned transition metal compound refining system, which comprises the following steps: powder is put into the evaporator, then inert gas is introduced into the gas pipe as a carrier gas, the sublimation gas flowing out of the gas outlet of the evaporator is carried into the primary crystallization chamber, and the sublimation gas is nucleated and condensed in the primary crystallization chamber. The system provided by the application realizes the refinement of the transition metal compound.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a refining system of transition metal compound and a refining method thereof. BACKGROUND

[0002] The transition metal compound is usually in powder form, such as transition metal compound containing tantalum, niobium, zirconium and hafnium. The prior art needs to use a gas phase deposition method to realize the deposition of these transition metal carbides. In order to achieve better deposition effect, finer powder is usually required.

[0003] For example, TaCl5, as a rare metal powder material, can be applied to important fields such as photocatalyst sodium tantalate for degrading organic wastewater, high specific capacity tantalum capacitor, corrosion-resistant metal tantalum coating, and carbon / carbon composite material anti-ablation TaC coating. In recent years, modern science and technology and military equipment are developing continuously, especially the aerospace field has put forward higher standards for the thermal protection of carbon / carbon composite materials. Chemical vapor deposition (CVD) is a relatively mature and widely used method for preparing high-quality TaC coating, and TaCl5 powder is a key raw material for preparing TaC coating by chemical vapor deposition process. With the continuous improvement of TaC deposition process, there is an increasingly urgent need for high-purity, fine-grained TaCl5 powder. The particle size distribution of TaCl5 powder will significantly affect the process control in the process of CVD preparation of TaC coating, and the use of nano TaCl5 powder can significantly improve the quality of CVD-TaC coating. At present, TaCl5 powder is synthesized by chlorination metallurgy. Although this method can synthesize TaCl5 powder with high purity, it is difficult to directly prepare primary fine-grained TaCl5 powder due to the limitation of the current process equipment capacity. Therefore, further treatment of the primary TaCl5 powder is needed to obtain ultra-fine nano TaCl5 powder with higher purity. Similarly, based on certain use requirements, other transition metal compounds also need to be treated to obtain finer powder.

[0004] How to obtain finer transition metal compound powder is a technical problem to be solved in the prior art. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies and provide a refining system of transition metal compound and a refining method thereof, which solves the technical problem of how to obtain finer transition metal compound powder in the prior art.

[0006] To achieve the above technical purpose, the technical scheme of the present application provides a refining system of transition metal compound, which comprises: an evaporation device and a primary crystallization chamber, the evaporation device and the primary crystallization chamber are in communication; the evaporation device comprises an evaporator, an air pipe and a heating element;

[0007] The evaporator is arranged in the heating element, the evaporator is provided with a feeding port and a gas outlet, the vent tube is communicated with the gas outlet of the evaporator, and the vent tube is used for introducing inert gas to carry the gas flowing out of the gas outlet of the evaporator into the primary crystallization chamber.

[0008] Further, the primary crystallization chamber comprises a first condenser tube, a flow divider and a first collector; the gas inlet end of the flow divider is connected with the gas outlet end of the vent tube, the gas outlet end of the flow divider is connected with the gas inlet end of the first collector, and the first condenser tube is arranged on the outer wall of the first collector; and / or, part of the vent tube is arranged below the evaporator at the bottom of the heating element, and the first gas inlet of the vent tube is arranged above the heating element; and / or, the transition metal compound is TaCl5.

[0009] Further, the heating element is a constant temperature oil bath device; and / or, the vent tube is a Venturi tube, the inner diameter of the gas outlet end of the Venturi tube is smaller than the inner diameter of the gas inlet end; and / or, further comprising a secondary crystallization chamber, the secondary crystallization chamber is communicated with the primary crystallization chamber.

[0010] Further, the flow divider comprises an outer ring channel and an inner ring channel, the inner ring channel is located inside the outer ring channel, the inner ring channel is communicated with the gas outlet end of the vent tube, the inner ring channel is used for introducing sublimation gas, the top of the outer ring channel is provided with a second gas inlet, the second gas inlet is used for introducing inert gas, and the inner ring channel and the outer ring channel are both communicated with the primary crystallization chamber.

[0011] Further, the outer ring channel is provided with a plurality of first gas flow channels, the bottom of each first gas flow channel is communicated with the primary crystallization chamber, the inclination angle of each first gas flow channel is 15-60 degrees, and each first gas flow channel gradually approaches the inner ring channel from top to bottom.

[0012] Further, the inner ring channel is provided with a plurality of second gas flow channels, the second gas flow channels are communicated with the primary crystallization chamber, and the second gas flow channels are used for introducing sublimation gas.

[0013] Further, the first collector comprises a collecting tube and a collecting plate, the collecting plate is arranged in the collecting tube, and the gas inlet end of the collecting tube is connected with the gas outlet end of the flow divider; and / or, the bottom of the collecting tube is provided with a plurality of gas inlets, and the plurality of gas inlets are used for introducing inert gas.

[0014] Further, the collecting plate comprises a plurality of collecting sub-plates, the plurality of collecting sub-plates are distributed in the collecting tube from top to bottom, and a plurality of third gas flow channels are arranged on the collecting sub-plates.

[0015] Further, the third airflow channels of the adjacent collecting sub-plates are staggered.

[0016] Further, the tail gas absorption device is connected with the primary crystallization chamber or the secondary crystallization chamber.

[0017] In addition, the application further provides a refining method of the transition metal compound refining system, comprising the following steps:

[0018] The powder is put into the evaporator, the temperature in the evaporator is controlled below 350 DEG C, then the inert gas is introduced into the air pipe as the carrier gas, the sublimation gas flowing out of the air outlet of the evaporator is carried into the primary crystallization chamber, and the sublimation gas nucleates and condenses in the primary crystallization chamber.

[0019] Compared with the prior art, the application has the beneficial effects that the powder to be treated is introduced into the evaporator, sublimates into gas under the heating action of the heating element, the inert gas is introduced into the air pipe, then the gas carried out of the air outlet of the evaporator is introduced into the primary crystallization chamber in communication with the evaporator to realize heterogeneous nucleation and condensation of the gas, finer transition metal compound is obtained, and the transition metal compound is refined. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic view of the powder refining system of the embodiment 1 of the application.

[0021] Figure 2 is a structural schematic view of the tail gas absorption device of the embodiment 1 of the application.

[0022] Figure 3 is a top view of the flow distribution disc of the embodiment 1 of the application.

[0023] Figure 4 is a sectional view of the flow distribution disc of the embodiment 1 of the application along Figure 3 A-A plane.

[0024] Legend: 1, evaporator; 11, evaporator; 111, feeding port; 112, first air outlet; 12, air pipe; 121, first air inlet; 13, heating element; 2, primary crystallization chamber; 21, first condensing pipe; 221, outer ring channel; 2211, first airflow channel; 222, inner ring channel; 2221, second airflow channel; 223, second air inlet; 23, first collector; 231, collecting pipe; 2311, air inlet channel; 232, collecting plate; 2321, collecting sub-plate; 23211, third airflow channel; 3, secondary crystallization chamber; 4, tail gas absorption device; 41, buffer tank; 42, vacuum pump; 43, absorption tank. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0026] Embodiment 1

[0027] In combination Figure 1-2 , the embodiment provides a powder refining system, comprising: an evaporation device 1 and a first crystallization chamber 2, the evaporation device 1 and the first crystallization chamber 2 being communicated; the evaporation device 1 comprising an evaporator 11, a gas pipe 12 and a heating element 13;

[0028] The evaporator 11 is arranged in the heating element 13, the evaporator 11 is provided with a feeding port 111 and a first gas outlet 112, the gas pipe 12 is communicated with the first gas outlet 112 of the evaporator 11, the gas pipe 12 is used for introducing inert gas to carry the gas flowing out of the first gas outlet 112 of the evaporator 11 into the first crystallization chamber 2, and the condensation of the gas is realized in the first crystallization chamber 2.

[0029] On the basis of the above-mentioned embodiment, the feeding port 111 in the embodiment is a feeding hopper, which is convenient for adding reactants.

[0030] On the basis of the above-mentioned embodiment, the first crystallization chamber 2 in the embodiment comprises a first condenser pipe 21, a flow divider and a first collector 23; the gas inlet end of the flow divider is connected with the gas outlet end of the gas pipe 12, the gas outlet end of the flow divider is connected with the gas inlet end of the first collector 23, and the first condenser pipe 21 is arranged on the outer wall of the first collector 23. The flow divider realizes the deceleration of steam, the first condenser pipe 21 ensures that the steam has a large supercooling degree, the supercooling degree is 50-100℃, ±5℃, and then the rapid nucleation and condensation of the steam are realized, and the temperature of the cooling water introduced into the first condenser pipe 21 is usually-10 to 0℃.

[0031] On the basis of the above-mentioned embodiment, part of the gas pipe 12 in the embodiment is arranged at the bottom of the heating element 13 and below the evaporator 11, and the first gas inlet 121 of the gas pipe 12 is arranged above the heating element 13. The inert gas introduced can be preheated in the heating element 13, and the preheating of the inert gas through the pipeline in the heating element 13 is high-temperature carrier gas, which is beneficial to ensure that the sublimation gas meets the inert gas with similar temperature in the gas pipe 12, and then prevents the sublimation gas from condensing in advance in the gas pipe 12.

[0032] On the basis of the above-mentioned embodiment, the heating element 13 in the embodiment is a constant-temperature oil bath device. The constant-temperature oil bath device can realize heating at a relatively stable temperature, ensure continuous and efficient heating of the evaporator 11, and thus ensure continuous evaporation of the powder to output sublimation gas.

[0033] On the basis of the above-mentioned embodiments, the vent pipe 12 in the present embodiment is a Venturi pipe, the inner diameter of the gas outlet end of the Venturi pipe is smaller than that of the gas inlet end. The gas from the evaporator 11 is made to quickly reach above the primary crystallization chamber 2, avoiding the condensation of the sublimated gas in the pipeline, and facilitating the subsequent condensation crystallization of the sublimated gas into the primary crystallization chamber 2.

[0034] In combination with Figure 1 , 3 and 4, on the basis of the above-mentioned embodiments, the shunt disc in the present embodiment comprises an outer ring channel 221 and an inner ring channel 222, the inner ring channel 222 is located inside the outer ring channel 221, the inner ring channel 222 is in communication with the gas outlet end of the vent pipe 12, and the inner ring channel 222 is used for passing in sublimated gas; the top of the outer ring channel 221 is provided with a second gas inlet 223, the second gas inlet 223 is used for passing in inert gas, and the inner ring channel 222 and the outer ring channel 221 are both in communication with the primary crystallization chamber 2. The sublimated gas enters from the inner ring channel 222 of the shunt disc, and is flushed into the primary crystallization chamber 2 under the action of the high-speed inert gas passed in the outer ring channel 221; the high-speed inert gas passed in the outer ring channel 221 slows down and disperses the sublimated gas in the inner ring channel 222, the high-temperature steam is quickly dispersed and uniform, and the flow speed of the high-temperature steam can be controlled by adjusting the speed of the inert gas passed in, so as to realize the buffering and dilution of the sublimated gas and ensure the uniformity of the crystalline particle size and its distribution.

[0035] On the basis of the above-mentioned embodiments, the outer ring channel 221 in the present embodiment is provided with a plurality of first gas flow channels 2211, the bottom of each first gas flow channel 2211 is in communication with the primary crystallization chamber 2, the inclination angle of each first gas flow channel 2211 is 15-60 degrees, and each first gas flow channel 2211 gradually approaches the inner ring channel 222 from the top to the bottom. This is convenient for the concentrated flushing and dispersion of the sublimated gas.

[0036] On the basis of the above-mentioned embodiments, the inner ring channel 222 in the present embodiment is provided with a plurality of second gas flow channels 2221, the second gas flow channels 2221 are in communication with the primary crystallization chamber 2, and the second gas flow channels 2221 are used for passing in sublimated gas. The sublimated gas enters from the second gas flow channels 2221.

[0037] On the basis of the above-mentioned embodiments, the first collector 23 in the present embodiment comprises a collection pipe 231 and a collection plate 232, the collection plate 232 is arranged in the collection pipe 231, and the gas inlet end of the collection pipe 231 is connected with the gas outlet end of the shunt disc. The buffered sublimated gas enters the first collector 23, nucleates and condenses in the first collector 23, and forms crystals on the collection plate 232.

[0038] Based on the above embodiment, the collection plate 232 of this embodiment includes multiple collection sub-plates 2321, which are distributed from top to bottom within the collection tube 231. The collection sub-plates 2321 are provided with multiple third airflow channels 23211. The multiple collection sub-plates 2321 enable crystals to nucleate and condense at different locations within the collection tube 231. In this embodiment, there are four collection sub-plates 2321.

[0039] Based on the above embodiment, the third air flow channels 23211 of adjacent collecting sub-plates 2321 of this embodiment are staggered to slow down the gas flow rate and facilitate the collection of crystallized powder.

[0040] Based on the above embodiment, the bottom of the collecting tube 231 of this embodiment is provided with multiple air inlet channels 2311 for introducing inert gas. The inert gas introduced from the bottom is used to backflush the buffered inert gas, thereby fully diluting the gas and facilitating rapid and sufficient crystallization.

[0041] Based on the above embodiment, this embodiment further includes a secondary crystallization chamber 3, which is connected to the primary crystallization chamber 2. The structure of the secondary crystallization chamber 3 is the same as that of the primary crystallization chamber 2, and can further collect the sublimated gas that has not been crystallized in the primary crystallization chamber 2, while also reducing the waste of raw materials and lowering costs. In this embodiment, only one secondary crystallization chamber 3 is provided. In other embodiments, depending on the crystallization situation and needs, two or three secondary crystallization chambers 3 may be provided to achieve sufficient crystallization. In this embodiment, the secondary crystallization chamber 3 is placed horizontally and connected to the middle of the first collection pipe 231.

[0042] On the basis of the above embodiment, the volume of the primary crystallization chamber 2 in this embodiment is 5 to 10 times the volume of the evaporator 11, and the inner surface area of ​​the primary crystallization chamber 2 is 10 to 20 times the inner surface area of ​​the evaporator 11, so as to facilitate the full condensation of the sublimated gas.

[0043] Based on the above embodiment, this embodiment further includes a tail gas absorption device 4, which is connected to the secondary crystallization chamber 3. A tail gas collection device can collect tail gas. In some embodiments, if there is no secondary crystallization chamber 3, the tail gas absorption device is connected to the primary crystallization chamber 2.

[0044] The tail gas absorption device 4 in this embodiment is composed of a buffer tank 41, a vacuum pump 42 and an absorption tank 43 connected in sequence with a bellows (not shown in the figure, but easy to understand). The buffer tank 41 is connected to the gas outlet end of the secondary crystallization chamber 3, wherein the buffer tank 41 contains a wire mesh and filter cotton for dust filtering, and a one-way stop valve is provided between the vacuum pump 42 and the absorption tank 43 to prevent air backflow, and the vacuum pump 42 realizes vacuuming of the entire system.

[0045] Example 2

[0046] This embodiment proposes a method for refining TaCl5 powder using the transition metal compound of embodiment 1. The vacuum degree of the system is 0.02 MPa, and then the system is filled with inert gas argon with a purity of 99.999% for replacement. After filling to atmospheric pressure, the operation is repeated twice. The vacuum degree of the system is controlled to be 0.1 MPa. The D50 of the TaCl5 powder is 50 um. The TaCl5 powder is placed in the constant temperature evaporation chamber. The volume of the TaCl5 powder accounts for 1 / 3 of the volume of the evaporator 11. The temperature of the constant temperature oil bath device is controlled at 250°C. The volume of the primary crystallization chamber 2 is 5 times that of the evaporator 11. The argon carrier gas with a flow rate of 100 L / min is filled. After 6 hours of sublimation, nucleation and crystallization, the TaCl5 powder is collected. The specific steps include the following steps:

[0047] (1) Selection of raw materials

[0048] In this embodiment, high-purity TaCl5 powder is selected as the raw material, and the purity is controlled to be more than 99.9%. High-purity argon is used as the carrier gas, and the purity is controlled to be more than 99.999% to avoid excessive impurity content in the final product.

[0049] (2) Gas replacement of the device

[0050] In order to ensure the airtightness of the evaporation device 1 and obtain an inert gas environment, the evaporation device 1 is first evacuated by the vacuum pump 42. The vacuum degree is controlled to be 0.02-0.1 MPa. Then, the argon is filled to the residual gas in the evaporator 11 to avoid the reaction of the TaCl5 powder with air.

[0051] (3) Vacuum evaporation of TaCl5 powder

[0052] The high-purity TaCl5 powder is placed in the feed hopper of the evaporator 11. The feed hopper switch is opened. The TaCl5 powder is sucked into the evaporator 11 by the negative pressure in the evaporator 11. Then, the feed hopper switch is closed. The temperature in the evaporator 11 is controlled to be 200-250°C. The argon is introduced as the carrier gas. The argon is preheated to high-temperature carrier gas through the pipeline in the evaporator 11, and the TaCl5 gas is brought to the flow divider.

[0053] (4) High-speed argon shunting and dilution

[0054] The high-pressure argon is introduced into the second gas inlet 223 above the flow divider. The TaCl5 gas is rapidly dispersed along the multiple gas flow channels of the flow divider. The TaCl5 gas enters the primary crystallization chamber 2. The backflushing buffer argon is introduced below the primary crystallization chamber 2 to fully dilute the TaCl5 gas.

[0055] (5) Multistage and multi-channel heterogeneous primary crystallization chamber 2 and secondary crystallization chamber 3 collect nano TaCl5 powder

[0056] The diluted TaCl5 gas enters the primary crystallization chamber 2 and the secondary crystallization chamber 3 for nucleation and condensation. A strong cooling channel is set in the crystallization chamber, and the cooling water temperature entering the condenser is between -10℃ and 0℃, providing a circulating cooling medium to ensure that the diluted TaCl5 gas has a large degree of supercooling (50-100℃, ±5℃). Subsequently, nucleation and condensation are carried out in the primary crystallization chamber and the secondary crystallization chamber.

[0057] (6) Tail gas recovery

[0058] The uncondensed TaCl5 vapor is collected along with the tail gas after passing through the buffer tank 41 and the absorption tank 43.

[0059] The test and analysis results are shown in Table 1 below:

[0060] Table 1

[0061] Example 2 Particle size D 50 / um purity [TaCl5] 0.3 99.925％

[0062] Example 3

[0063] Referring to the method of Example 2, the vacuum pump 42 was used to draw the system vacuum degree to 0.02MPa, and argon gas with a purity of 99.999% was filled to replace the inert gas. After filling to normal pressure, this operation was repeated once, and the control system vacuum degree was 0.05MPa. TaCl5 powder with a D50 of 50μm was placed in the evaporator 11. The volume of TaCl5 powder accounted for 1 / 2 of the volume of the evaporator 11, and the temperature of the oil bath was controlled at 200°C. The volume of the primary crystallization chamber 2 was 5 times that of the evaporator 11, and argon carrier gas with a flow rate of 150L / min was filled. After 8 hours of sublimation, nucleation and crystallization, TaCl5 powder was collected. The results of the test analysis are shown in Table 2 below.

[0064] Table 2

[0065] Example 3 <![CDATA[粒径D 50 / one]]> purity <![CDATA[TaCl5]]> 0.25 99.918％

[0066] Example 4

[0067] Referring to the method of Example 2, the vacuum pump 42 was used to draw the system vacuum degree to 0.02 MPa, and argon gas with a purity of 99.999% was filled to replace the inert gas. After filling to normal pressure, this operation was repeated once, and the control system vacuum degree was 0.05 MPa. TaCl5 powder with a D50 of 30 μm was placed in the evaporation device 1. The volume of TaCl5 powder accounted for 1 / 3 of the volume of the evaporator 11, and the temperature of the evaporator 11 was controlled at 200°C. The volume of the primary crystallization chamber 2 is 10 times that of the evaporator 11. It was filled with argon carrier gas at a flow rate of 200 L / min. After 8 hours of sublimation, nucleation and crystallization, the TaCl5 powder was collected. The results of the test analysis are shown in Table 3 below.

[0068] Table 3

[0069] Example 4 Particle size D 50 / um purity [TaCl5] 0.2 99.928％

[0070] This invention proposes a method and system for preparing nano-scale TaCl₅ powder. Key process technologies include precise temperature control in a circulating oil bath, high-temperature, high-speed inert gas conveying of gaseous TaCl₅, multi-channel, high-speed airflow dispersion, ultra-high supercooling heterogeneous nucleation and recrystallization, multi-stage high-purity, ultrafine nanopowder recovery, and efficient, pollution-free waste gas recovery. This method achieves the production of high-purity nano-TaCl₅ powder. This process is highly efficient, low in energy consumption, minimizes environmental pollution, and produces a high yield of fine powder with controllable particle size.

[0071] The powder in the above embodiment is TaCl5 powder. In fact, the above system is also applicable to transition metal compounds containing tantalum, niobium, zirconium, hafnium, etc. with a boiling point below 350°C.

[0072] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A refinement system for a transition metal compound, characterized in that: include: An evaporation device and a primary crystallization chamber, wherein the evaporation device and the primary crystallization chamber are in communication; the evaporation device comprises an evaporator, a vent pipe and a heating element; The evaporator is arranged in the heating element, and the evaporator is provided with a feeding port and an air outlet. The vent pipe is connected to the air outlet of the evaporator, and the vent pipe is used to introduce inert gas and then carry the gas flowing out of the air outlet of the evaporator into the primary crystallization chamber; The primary crystallization chamber includes a first condenser, a diverter plate, and a first collector; the air inlet end of the diverter plate is connected to the air outlet end of the vent pipe, the air outlet end of the diverter plate is connected to the air inlet end of the first collector, and the first condenser is provided on the outer wall of the first collector; The diverter plate includes an outer ring channel and an inner ring channel, the inner ring channel is located inside the outer ring channel, the inner ring channel is connected to the gas outlet end of the vent pipe, the inner ring channel is used to introduce sublimation gas, the top of the outer ring channel is provided with a second gas inlet, the second gas inlet is used to introduce inert gas, and the inner ring channel and the outer ring channel are both connected to the primary crystallization chamber; The outer ring channel is provided with a plurality of first air flow channels, the bottom of the first air flow channels is connected to the primary crystallization chamber, the inclination angle of each first air flow channel is 15-60 degrees, and each first air flow channel gradually approaches the inner ring channel from top to bottom.

2. The system for refining transition metal compounds according to claim 1, characterized in that Part of the vent pipe is arranged at the bottom of the heating element and below the evaporator, and the first air inlet of the vent pipe is arranged above the heating element; and / or, the transition metal compound is TaCl5.

3. The system for refining transition metal compounds according to claim 1, characterized in that The heating element is a constant temperature oil bath device; and / or, the vent pipe is a venturi tube, the inner diameter of the air outlet end of the venturi tube is smaller than the inner diameter of the air inlet end thereof; and / or, it also includes a secondary crystallization chamber, which is connected to the primary crystallization chamber.

4. The system for refining transition metal compounds according to claim 1, characterized in that The inner ring channel is provided with a plurality of second air flow channels, the second air flow channels are communicated with the primary crystallization chamber, and the second air flow channels are used for introducing sublimation gas.

5. The system for refining transition metal compounds according to claim 1, characterized in that The first collector includes a collecting tube and a collecting plate, wherein the collecting plate is arranged in the collecting tube, and the air inlet end of the collecting tube is connected to the air outlet end of the diverter plate; and / or, a plurality of air inlet channels are provided at the bottom of the collecting tube, and the plurality of air inlet channels are used to introduce inert gas.

6. The system for refining transition metal compounds according to claim 5, characterized in that The collecting plate includes a plurality of collecting sub-plates, which are distributed in the collecting tube from top to bottom. The collecting sub-plates are provided with a plurality of third air flow channels; the third air flow channels of adjacent collecting sub-plates are staggered.

7. The system for refining transition metal compounds according to claim 1 or 2, characterized in that: It also includes a tail gas absorption device, which is connected to the primary crystallization chamber.

8. The system for refining transition metal compounds according to claim 3, characterized in that It also includes a tail gas absorption device, which is connected to the secondary crystallization chamber.

9. A method for refining a transition metal compound according to any one of claims 1 to 8, characterized in that: The following steps are involved: The powder is placed in the evaporator, and the temperature inside the evaporator is controlled below 350°C. Then, an inert gas is introduced from the vent pipe as a carrier gas, and the sublimated gas flowing out of the evaporator outlet is brought to the primary crystallization chamber. The sublimated gas enters the primary crystallization chamber for nucleation and condensation.

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