Device and method for improving tungsten hexafluoride synthesis efficiency of fluidized bed reactor

Abstract

The invention belongs to the technical field of fluorine-containing fine chemical synthesis, and particularly relates to a device and a method for improving tungsten hexafluoride synthesis efficiency of a fluidized bed reactor. The method comprises the following steps: adding tungsten powder and nickel powder into a stirring kettle, uniformly mixing the tungsten powder and the nickel powder to obtain a mixture, feeding the mixture into a reactor by using nitrogen, heating the reactor to 240-280 DEG C, introducing feed gas NF3 with the pressure of 0.2 MPa into the reactor through a first raw material tank / a second raw material tank, and reacting to obtain crude tungsten hexafluoride, after metal impurities are separated from the product gas through the first-stage cyclone separator and the second-stage cyclone separator, the product gas enters the heat exchanger to be cooled and finally enters the collecting tank, and metal powder separated by the cyclone separators is recycled into a dust collecting system and conveyed to the stirring kettle through nitrogen pressure to be recycled. By adding the nickel powder, fluidization of the tungsten powder can be achieved, continuous circular reaction can be achieved, only the nickel powder and the tungsten powder need to be recycled regularly except for controlling the flow speed of NF3, operation is simplified, cost is reduced, and the reaction efficiency is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine-containing fine chemical synthesis, and specifically relates to a device and a method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor. Background Art

[0002] Tungsten hexafluoride is an electronic gas widely used in the field of ultra-large-scale circuits and semiconductor materials. As the main raw material of the chemical vapor deposition (CVD) process, tungsten hexafluoride is the main chemical gas used to manufacture large-scale integrated circuits. At present, the industry generally uses tungsten and fluorine gas or NF3 to directly react to synthesize tungsten hexafluoride, but both of them have the disadvantages of small gas-solid reaction contact area and low reaction efficiency.

[0003] After consulting the literature, we know that particles with different particle sizes have different fluidization properties. Fine particles (170um~1700um) are easier to fluidize than coarse particles (1700um~2500um). If the particles are too fine (5um~170um), it is difficult to achieve fluidization due to the strong drag between the particles. Particles that are too coarse can only be used in solid phase processing processes such as roasting and drying.

[0004] The application with announcement number CN101723465A discloses a method and apparatus for preparing tungsten hexafluoride using a fluidized bed reactor, and discloses a method of fluidizing tungsten powder by injecting pressurized inert gas into the reactor. Although this method produces a high-purity product, the introduction of inert gas increases the separation of gas impurities.

[0005] The announcement number is CN101428858A, a method for preparing high-purity tungsten hexafluoride in a fluidized bed and its equipment, which discloses a method of passing fluorine gas into a fluidized bed reactor, continuously passing tungsten powder into the reactor, and nitrogen entering the reactor from a gas distributor at the bottom of the reactor to suspend the tungsten powder in the reactor. Non-condensable impurities in the reactor gas product are removed by a vacuum system. The product gas prepared by this method has high purity, but the fluorinating agent is fluorine gas, which has poor safety, and introduces inert gas nitrogen impurities, which increases the difficulty of separation.

[0006] Announcement No. CN108946816A discloses a method for preparing tungsten hexafluoride and a reactor thereof, which discloses a vertical tubular reactor that improves reaction efficiency through a secondary reaction. Fluorine gas is used as a fluorinating agent, resulting in poor safety of the method, and the final fluorine gas reaction efficiency is above 95%, and the reaction efficiency still needs to be improved.

[0007] In summary, the existing industrial preparation methods of tungsten hexafluoride generally have the disadvantages of introducing inert gas impurities, great difficulty in separation, and poor system safety, while fine-grained tungsten powder has the disadvantage of being difficult to achieve stable fluidization. Summary of the invention

[0008] This application aims at the disadvantages of the existing methods for preparing tungsten hexafluoride, such as the introduction of inert gas impurities, the difficulty in separation, and the poor system safety. In addition, fine-grained tungsten powder has the disadvantage of being difficult to achieve stable fluidization. In order to solve the problem that fine-grained tungsten powder is difficult to achieve stable fluidization and the system has poor circulation and safety, this application proposes a method in which a certain proportion of nickel powder is added to fine-grained tungsten powder to improve the fluidization performance of fine-grained tungsten powder, and raw gas NF3 is used as a booster gas to prepare high-purity tungsten hexafluoride, which is achieved through an in-line tubular fluidized reactor. The technical solution of this application is as follows:

[0009] On the one hand, the present application provides a device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, comprising a feed reaction unit, a separation unit and a product collection unit;

[0010] The feed reaction unit includes an air inlet device for introducing raw material gas, a stirring kettle for mixing the reaction raw materials, and a reactor for generating tungsten hexafluoride, wherein the air inlet device is connected to the stirring kettle, and the stirring kettle is connected to the reactor;

[0011] The separation unit comprises a cyclone separation device for solid-gas separation and a collection device for collecting metal powder, the top of the cyclone separation device is connected to the reactor, the bottom of the cyclone separation device is connected to the collection device, and the bottom of the collection device is connected to the stirring tank;

[0012] The product collection unit includes a heat exchanger for cooling tungsten hexafluoride and a collection tank for collecting the product tungsten hexafluoride. One end of the heat exchanger is connected to the cyclone separation device, and the other end is connected to the collection tank.

[0013] Preferably, the gas inlet device comprises a first raw material tank and a second raw material tank for storing NF3 gas, and the first raw material tank and the second raw material tank are connected in parallel and then connected to the bottom of the reactor.

[0014] Preferably, the cyclone separation device includes a primary cyclone separator and a secondary cyclone separator, the primary cyclone separator and the secondary cyclone separator are connected in series, the top of the primary cyclone separator is connected to the reactor, and the secondary cyclone separator is connected to the heat exchanger; the collecting device includes a primary dust collecting tank and a secondary dust collecting tank, the primary dust collecting tank is connected to the bottom of the primary cyclone separator, the secondary dust collecting tank is connected to the bottom of the secondary cyclone separator, and the bottoms of the primary dust collecting tank and the secondary dust collecting tank are both connected to the reactor; the primary dust collecting tank, the secondary dust collecting tank, the primary cyclone separator and the secondary cyclone separator are all made of stainless steel.

[0015] Preferably, the pipeline connecting the primary dust collecting tank and the primary cyclone separator and the pipeline connecting the secondary dust collecting tank and the secondary cyclone separator are both connected to the high-pressure nitrogen pipeline, and the high-pressure nitrogen pipeline is used to press the metal powder in the primary dust collecting tank and the secondary dust collecting tank into the stirring kettle.

[0016] Preferably, the stirring kettle is made of stainless steel, and a stirring device is provided inside the stirring kettle. The stirring device includes a driving motor, a stirring shaft and a plurality of stirring blades. The driving motor is fixedly arranged on the upper part of the stirring kettle, and the driving shaft of the driving motor is fixedly connected to the stirring shaft, and a plurality of stirring blades are evenly fixed on the stirring shaft.

[0017] Preferably, the reactor is an in-line tubular fluidized bed reactor, and the material of the reactor is monel alloy; the heat exchanger is a shell and tube heat exchanger, and the material of the heat exchanger is stainless steel.

[0018] Preferably, the collection tank is also connected to a gas analyzer for detecting gas purity.

[0019] On the other hand, the present application provides a method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, the specific steps of which are: adding tungsten powder and nickel powder into a stirring tank, mixing the tungsten powder and nickel powder to obtain a mixture, pressing the mixture into a reactor with nitrogen, then heating the reactor to 240-280°C, and introducing raw gas NF3 with a pressure of 0.2MPa into the reactor through a first raw material tank / second raw material tank to react and obtain crude tungsten hexafluoride. The product gas passes through a primary cyclone separator and a secondary cyclone separator to separate metal impurities, then enters a heat exchanger for cooling, and finally enters a collection tank, wherein the metal powder separated by the cyclone separator is collected in a dust collection system and pressed to a stirring tank for recycling using high-pressure nitrogen.

[0020] Preferably, the mass ratio of the tungsten powder to the nickel powder is 1:1 to 1:4, the purity of the tungsten powder is 99.5%, the particle size is less than 10um, and the particle size of the nickel powder is 200 to 500um; the air flow rate of the raw gas NF3 is 20 to 25m / s; the circulation ratio of the metal powder returning to the dust collection system and being pressed to the stirring tank by nitrogen is 1:5 to 1:9, and the temperature of the collection tank is -30 to -110°C.

[0021] Preferably, the diameter of the reactor (3) is 500-800 mm, the bed height of the reactor (3) is 210-350 mm, the filler of the reactor (3) is bulk filler, the filler equivalent diameter is 200-500 mm, and the filling height of the filler is 200-400 mm.

[0022] The beneficial effects of this application are as follows:

[0023] By adding nickel powder to the reaction system, the fluidization characteristics of tungsten powder are improved, making it more fluid, which is convenient for mixing, transporting and handling during the reaction process. The realization of this fluidization makes continuous cycle reaction possible, greatly improving production efficiency and operational flexibility.

[0024] In the continuous cycle reaction system, in addition to the need to accurately control the flow rate of NF3 between 20 and 25 m / s to ensure the safety and efficiency of the reaction, the simplicity of operation and cost control are also fully considered. Since nickel powder and tungsten powder can be recycled in the reaction, only the two powders need to be recycled regularly to avoid frequent material replacement and waste. This design not only simplifies the operation process and reduces labor costs, but also reduces the consumption of raw materials, thereby achieving effective cost control.

[0025] In summary, the addition of nickel powder helps to achieve the fluidization of tungsten powder, and the fluidizing gas itself is used as the reaction gas raw material, avoiding the introduction of other fluidizing gas impurities, and can achieve continuous operation with good safety and high reaction efficiency. In addition to controlling the NF3 flow rate, it is only necessary to regularly recycle nickel powder and tungsten powder, which simplifies the operation and reduces costs, and also greatly improves the reaction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attached Figure 1 A diagram of a device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor for this application;

[0027] Figure ID:

[0028] 1. First raw material tank; 2. Second raw material tank; 3. Reactor; 4. Primary cyclone separator; 5. Secondary cyclone separator; 6. Heat exchanger; 7. Collection tank; 8. Primary dust collecting tank; 9. Secondary dust collecting tank; 10. Stirring kettle. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present application are described in detail below in combination with the preferred embodiments.

[0030] Reference Figure 1 , the present application requests to disclose a device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, comprising a feed reaction unit, a separation unit and a product collection unit;

[0031] The feed reaction unit of this embodiment includes an air intake device for introducing raw material gas, a stirring tank 10 for mixing the reaction raw materials, and a reactor 3 for generating tungsten hexafluoride. The air intake device is connected to the side of the stirring tank 10 through a pipeline, and the upper part of the stirring tank 10 is connected to the top of the reactor 3 through a pipeline; the air intake device includes a first raw material tank 1 and a second raw material tank 2 for storing NF3 gas. The first raw material tank 1 and the second raw material tank 2 are connected in parallel and connected to the bottom of the reactor 3. The first raw material tank 1 and the second raw material tank 2 are two independent tanks, both for storing NF3 gas. The two raw material tanks are connected in parallel, that is, they each have an independent outlet valve, but the outlet valves are combined into a main delivery pipeline through a three-way joint or a similar device, and the pipeline directly extends to the bottom of the reactor 3. Such a design not only ensures the stability of the raw material supply, but also facilitates switching or maintenance when necessary. The stirring tank 10 of this embodiment is made of stainless steel, and a stirring device is provided inside the stirring tank 10. The stirring device includes a driving motor, a stirring shaft and a plurality of stirring blades. The driving motor is fixedly arranged on the upper part of the stirring tank 10, and the driving shaft of the driving motor is fixedly connected to the stirring shaft. A plurality of stirring blades are evenly fixed on the stirring shaft. First, metal nickel powder and tungsten powder are put into the stirring tank 10 in proportion through an automatic feeding device, and the preliminary mixing is uniform, which helps to achieve the fluidization of tungsten powder. The reactor 3 of this embodiment is an in-line tubular fluidized reactor, and the material of the reactor 3 is monel alloy; the reactor 3 of this embodiment has multiple advantages of efficient heat and mass transfer, low pressure loss, easy maintenance and cleaning, high corrosion resistance and high temperature resistance, which ensures the stable operation of the reactor 3 in harsh chemical environments and improves production efficiency and equipment life.

[0032] The separation unit of this embodiment includes a cyclone separation device for solid-gas separation and a collection device for collecting metal powders. The cyclone separation device includes a primary cyclone separator 4 and a secondary cyclone separator 5. The primary cyclone separator 4 and the secondary cyclone separator 5 are connected in series. The top of the primary cyclone separator 4 is connected to the reactor 3, and the secondary cyclone separator 5 is connected to the heat exchanger 6. In this embodiment, by connecting the primary cyclone separator 4 and the secondary cyclone separator 5 in series, efficient solid-gas separation is achieved, and metal nickel and tungsten powders are effectively collected. The primary cyclone separator 4 directly receives the material at the outlet of the reactor 3 and preliminarily removes large particles; the secondary cyclone separator 5 further refines the separation to ensure gas purity.

[0033] The collecting device includes a primary dust collecting tank 8 and a secondary dust collecting tank 9. The primary dust collecting tank 8 is connected to the bottom of the primary cyclone separator 4, the secondary dust collecting tank 9 is connected to the bottom of the secondary cyclone separator 5, and the bottoms of the primary dust collecting tank 8 and the secondary dust collecting tank 9 are both connected to the reactor 3; the primary dust collecting tank 8, the secondary dust collecting tank 9, the primary cyclone separator 4 and the secondary cyclone separator 5 are all made of stainless steel. The pipeline connecting the primary dust collecting tank 8 and the primary cyclone separator 4 and the pipeline connecting the secondary dust collecting tank 9 and the secondary cyclone separator 5 are both connected to the high-pressure nitrogen pipeline, and the high-pressure nitrogen pipeline is used to press the metal powder in the primary dust collecting tank 8 and the secondary dust collecting tank 9 into the stirring kettle 10. The collecting device of this embodiment is connected to the primary cyclone separator 4 and the secondary cyclone separator 5 respectively through the primary dust collecting tank 8 and the secondary dust collecting tank 9 made of stainless steel, thereby ensuring efficient metal powder collection and corrosion resistance. The access to the high-pressure nitrogen pipeline not only helps to clean the pipeline, but also can safely and efficiently press the metal powder nickel powder and tungsten powder into the stirring tank 10 to achieve the recycling of the powder.

[0034] The product collection unit of this embodiment includes a heat exchanger 6 for cooling tungsten hexafluoride and a collection tank 7 for collecting the product tungsten hexafluoride. One end of the heat exchanger 6 is connected to the secondary cyclone separation gas, and the other end is connected to the collection tank 7. The collection tank 7 is also connected to a gas analyzer for detecting gas purity.

[0035] The heat exchanger 6 of this embodiment is a shell and tube heat exchanger. The material of the heat exchanger 6 is stainless steel, which not only has high heat exchange efficiency, but also has excellent corrosion resistance and high strength, ensuring the long-term stable operation of the heat exchanger 6.

[0036] Implementation principle of this device: Before the experiment begins, ensure that the first raw material tank 1 and the second raw material tank 2 are filled with NF3 gas, and the valves of the two tanks are in a closed state. Metal nickel powder and tungsten powder are fed into the stirring tank 10 through an automatic feeding device according to a predetermined ratio. Start the driving motor of the stirring tank 10, and the stirring shaft drives the stirring blades to rotate, and the metal nickel powder and tungsten powder are preliminarily mixed in the stirring tank 10, which helps to achieve the fluidization of the tungsten powder. The evenly mixed material enters the in-line tubular fluidized reactor through a pipeline from the stirring tank 10. The interior of the reactor 3 is filled with bulk fillers, which can be ball rings or Raschig rings or a combination of the two fillers to improve the reaction efficiency.

[0037] Open the outlet valve of the first raw material tank 1 or the second raw material tank 2 (usually open one first and the other as a backup), and the NF3 gas enters the reactor 3 through the pipeline connected in parallel with the first raw material tank 1 and the second raw material tank 2 to mix and react with the metal powder. In the reactor 3, the NF3 gas and the metal powder react chemically at high temperature. The reacted material (containing tungsten hexafluoride gas and unreacted metal powder) enters the primary cyclone separator 4 from the reactor 3. The primary cyclone separator 4 preliminarily separates the large particles of metal powder in the material through centrifugal force and falls into the primary dust collecting tank 8. The separated gas (containing tungsten hexafluoride and small particles of metal powder) enters the secondary cyclone separator 5 for further refinement and separation. The secondary cyclone separator 5 separates the small particles of metal powder in the gas and falls into the secondary dust collecting tank 9.

[0038] The metal powder in the primary dust collecting tank 8 and the secondary dust collecting tank 9 is pressed back to the stirring tank 10 through the high-pressure nitrogen pipeline to achieve the recycling of the powder. The pure tungsten hexafluoride gas separated by the secondary cyclone separator 5 enters the shell and tube heat exchanger 6 for cooling treatment. The cooled tungsten hexafluoride gas enters the collection tank 7 for collection. The collection tank 7 is also connected to a gas analyzer for detecting gas purity to ensure that the product quality meets the requirements. When the entire test is completed, all valves and power supplies should be closed, the equipment should be disconnected, and the stirring tank 10, reactor 3, cyclone separator, dust collecting tank and heat exchanger 6 and other equipment should be cleaned and maintained.

[0039] Based on the device provided in the equipment embodiment, embodiments 1 to 4 provide a method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor. In order to avoid the reactor from changing back and forth and increasing the complexity of the experiment, the diameter of the reactor selected in embodiments 1 to 4 is 600 mm. However, after preliminary experiments, the applicant found that 500 to 800 mm within the range recorded in this application meets the requirements of this application. It should be noted that the specific details are as follows:

[0040] Example 1

[0041] This embodiment provides a method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, wherein tungsten powder and nickel powder are uniformly mixed in a weight ratio of 1:1, the particle size of nickel powder is 200-500um, the purity of nickel powder is 99.95%, the particle size of tungsten powder is <10um, the purity of tungsten powder is 99.95%, the circulation ratio is 1:5, the bed height of reactor 3 is 300mm, the equivalent diameter of filler is 300-350mm, the filling height of filler is 200mm, the NF3 gas velocity is 20m / s, and the purity of NF3 is 99.996%. The pressure in reactor 3 is controlled at about 0.2MPa, and the product continuously passes through the primary cyclone separator 4, the secondary cyclone separator 5 and the heat exchanger 6 into the collection tank 7, and the collection temperature of the collection tank 7 is -30--50°C. The raw material conversion rate is calculated by actual analysis and comparison to be 99.1%, and the product gas components are characterized by gas chromatography, wherein the concentration of NF3 in the product gas is 9000ppm.

[0042] Example 2

[0043] A method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, wherein tungsten powder and nickel powder are uniformly mixed in a weight ratio of 1:2, the nickel powder particle size is 200-500um, the nickel powder purity is 99.95%, the tungsten powder particle size is less than 10um, the tungsten powder purity is 99.95%, the circulation ratio is 1; 5.8, the bed height of the reactor 3 is 350mm, the equivalent diameter of the filler is 210-300mm, the filling height of the filler is 300mm, the NF3 gas velocity is 22m / s, and the NF3 purity is 99.996%. The pressure in the reactor 3 is controlled at about 0.2MPa, and the product continuously passes through the primary cyclone separator 4, the secondary cyclone separator 5 and the heat exchanger 6 into the collection tank 7, the collection temperature of the collection tank 7 is -50--80℃, and the raw material conversion rate is calculated by actual analysis and comparison to be 99.3%, wherein the concentration of NF3 in the product gas is 7000ppm.

[0044] Example 3

[0045] A method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, wherein tungsten powder and nickel powder are uniformly mixed in a weight ratio of 1:3, the nickel powder particle size is 200-500um, the nickel powder purity is 99.95%, the tungsten powder particle size is less than 10um, the tungsten powder purity is 99.95%, the circulation ratio is 1:9, the bed height of the reactor 3 is 210mm, the equivalent diameter of the filler is 250-280mm, the filling height of the filler is 400mm, the NF3 gas velocity is 23m / s, and the NF3 purity is 99.996%. The pressure in the reactor 3 is controlled at about 0.2MPa, and the product continuously passes through the primary cyclone separator 4, the secondary cyclone separator 5 and the heat exchanger 6 into the collection tank 7, the collection temperature of the collection tank 7 is -80--100°C, and the raw material conversion rate is calculated by actual analysis and comparison to be 99.6%, wherein the concentration of NF3 in the product gas is 4000ppm.

[0046] Example 4

[0047] A method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, wherein tungsten powder and nickel powder are uniformly mixed in a weight ratio of 1:4, the nickel powder particle size is 200-500um, the nickel powder purity is 99.95%, the tungsten powder particle size is less than 10um, the tungsten powder purity is 99.95%, the circulation ratio is 1:7.6, the bed height of the reactor 3 is 320mm, the equivalent diameter of the filler is 280-310mm, the filling height of the filler is 350mm, the NF3 gas velocity is 25m / s, and the NF3 purity is 99.996%. The pressure in the reactor 3 is controlled at about 0.2MPa, and the product continuously passes through the primary cyclone separator 4, the secondary cyclone separator 5 and the heat exchanger 6 into the collection tank 7, the collection temperature of the collection tank 7 is -90--110°C, and the raw material conversion rate is calculated by actual analysis and comparison to be 99.4%, wherein the concentration of NF3 in the product gas is 6000ppm.

[0048] It can be seen from the results of Examples 1 to 4 that the method and apparatus for preparing tungsten hexafluoride of the present application can achieve an impurity component concentration at the ppm level, and the concentration can satisfy the impurity component NF3 content ≤ 10000 ppm.

[0049] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, characterized in that: It includes a feed reaction unit, a separation unit and a product collection unit; The feed reaction unit comprises an air intake device for introducing raw material gas, a stirring tank (10) for mixing the reaction raw materials, and a reactor (3) for generating tungsten hexafluoride, wherein the air intake device is connected to the stirring tank (10), and the stirring tank (10) is connected to the reactor (3); The separation unit comprises a cyclone separation device for solid-gas separation and a collection device for collecting metal powder, the top of the cyclone separation device is connected to the reactor (3), the bottom of the cyclone separation device is connected to the collection device, and the bottom of the collection device is connected to the stirring tank (10); The product collection unit comprises a heat exchanger (6) for cooling tungsten hexafluoride and a collection tank (7) for collecting the product tungsten hexafluoride. One end of the heat exchanger (6) is connected to the cyclone separation device, and the other end is connected to the collection tank (7).

2. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 1, characterized in that: The gas inlet device comprises a first raw material tank (1) and a second raw material tank (2) for storing NF3 gas. The first raw material tank (1) and the second raw material tank (2) are connected in parallel and then connected to the bottom of the reactor (3).

3. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 1, characterized in that: The cyclone separation device comprises a primary cyclone separator (4) and a secondary cyclone separator (5), the primary cyclone separator (4) and the secondary cyclone separator (5) are connected in series, the top of the primary cyclone separator (4) is connected to the reactor (3), and the secondary cyclone separator (5) is connected to the heat exchanger (6); the collecting device comprises a primary dust collecting tank (8) and a secondary dust collecting tank (9), the primary dust collecting tank (8) is connected to the bottom of the primary cyclone separator (4), the secondary dust collecting tank (9) is connected to the bottom of the secondary cyclone separator (5), and the bottoms of the primary dust collecting tank (8) and the secondary dust collecting tank (9) are both connected to the reactor (3); the primary dust collecting tank (8), the secondary dust collecting tank (9), the primary cyclone separator (4) and the secondary cyclone separator (5) are all made of stainless steel.

4. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 3, characterized in that: The pipeline connecting the primary dust collecting tank (8) and the primary cyclone separator (4) and the pipeline connecting the secondary dust collecting tank (9) and the secondary cyclone separator (5) are both connected to a high-pressure nitrogen pipeline, and the high-pressure nitrogen pipeline is used to press the metal powder in the primary dust collecting tank (8) and the secondary dust collecting tank (9) into the stirring kettle (10).

5. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 1, characterized in that: The stirring kettle (10) is made of stainless steel. A stirring device is provided inside the stirring kettle (10). The stirring device comprises a driving motor, a stirring shaft and a plurality of stirring blades. The driving motor is fixedly arranged on the upper part of the stirring kettle (10). The driving shaft of the driving motor is fixedly connected to the stirring shaft. The plurality of stirring blades are evenly fixed on the stirring shaft.

6. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 1, characterized in that: The reactor (3) is an in-line tubular fluidized reactor, and the material of the reactor (3) is monel alloy; the heat exchanger (6) is a shell and tube heat exchanger, and the material of the heat exchanger (6) is stainless steel.

7. The device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 1, characterized in that: The collecting tank (7) is also connected to a gas analyzer for detecting gas purity.

8. A method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor, based on a device for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor as claimed in any one of claims 1 to 7, characterized in that: The specific steps are as follows: tungsten powder and nickel powder are added to a stirring kettle (10), and after the tungsten powder and the nickel powder are mixed, a mixture is obtained, and the mixture is pressed into a reactor (3) by nitrogen. Then, after the reactor (3) is heated to 240-280° C., a raw material gas NF3 with a pressure of 0.2 MPa is introduced into the reactor (3) through a first raw material tank (1) / a second raw material tank (2) to obtain a crude tungsten hexafluoride. The product gas is separated from metal impurities by a primary cyclone separator (4) and a secondary cyclone separator (5), and then enters a heat exchanger (6) for cooling, and finally enters a collecting tank (7), wherein the metal powder separated by the cyclone separation device is recovered into a dust collection system, and is pressed into the stirring kettle (10) by nitrogen for recycling.

9. A method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 8, characterized in that: The mass ratio of the tungsten powder to the nickel powder is 1:1 to 1:4, the purity of the tungsten powder is 99.5%, the particle size is less than 10um, and the particle size of the nickel powder is 200 to 500um; the air flow rate of the raw gas NF3 is 20 to 25m / s; the circulation ratio of the metal powder returning to the dust collection system and being conveyed to the stirring kettle (10) by nitrogen pressure is 1:5 to 1:9, and the temperature of the collection tank (7) is -30 to -110°C.

10. The method for improving the efficiency of synthesizing tungsten hexafluoride in a fluidized bed reactor according to claim 8, characterized in that: The diameter of the reactor (3) is 500-800 mm, the bed height of the reactor (3) is 210-350 mm, the filler of the reactor (3) is bulk filler, the filler equivalent diameter is 200-500 mm, and the filling height of the filler is 200-400 mm.

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