A production device and application for preparing nitrogen trifluoride gas by long-term continuous electrolysis

Abstract

The application discloses a production device for preparing nitrogen trifluoride gas by long-term continuous electrolysis, which comprises a raw material tank, a first pump body, an electrolytic tank, a sedimentation tank, a second pump body, a filter and a collection tank which are sequentially connected through pipelines, and a third pump body is further connected with the top of the raw material tank; the electrolytic tank comprises a tank body, a cathode cover is installed on the upper end of the tank body, an anode cover is installed in the middle of the cathode cover, and the anode cover and the cathode cover are in sealing connection; a gas outlet pipe is arranged at one end of the anode cover, an anode inert gas inlet is arranged at the other end of the anode cover, a cathode gas outlet and a cathode inert gas inlet are arranged through the cathode cover. The application utilizes electrolyte circulation to achieve self-purification effect, solves the problem that electrolysis is terminated due to deposition of electrolytic solid waste in traditional electrolytic tanks, and can directly replace the anode to solve the problem that electrolysis is terminated due to expiration of the anode in traditional electrolytic tanks.

Description

Technical Field

[0001] This invention belongs to the technical field of nitrogen trifluoride preparation, specifically relating to a production apparatus and its application for the long-term continuous electrolytic preparation of nitrogen trifluoride gas. Background Technology

[0002] Nitrogen trifluoride (NF3) is a specialty electronic gas with wide and important applications in the semiconductor and LCD panel industries. The main method for producing NF3 gas is molten salt electrolysis. The anode is a nickel anode, the electrolyte is NH3·xHF molten salt, and the electrolysis temperature is 90℃~140℃. NF3 is produced at the anode, and H2 is produced at the cathode. The basic design of the NF3 electrolyzer is to divide the gas space of the electrolyzer into an anode region and a cathode region using a skirt and electrolyte. The gas from the anode and cathode exits the electrolyzer from the anode region to the anode gas collection system and the cathode gas collection system, respectively, utilizing the drift angles of the anode and cathode gases in the electrolyte.

[0003] The existing NF3 electrolytic cell structure is basically divided into five parts: cell cover, skirt, anode, cathode, and cell body. There are two main structural designs: One is where the skirt is welded to the cell cover, and the anode and cathode are bolted to the cell cover via anode and cathode terminals respectively. The cell cover is then fastened to the cell body with bolts or clamps. The other design divides the cell cover into a cathode cover and an anode cover. The skirt is welded to the cathode cover, and the anode is bolted to the anode cover via anode terminals. The cathode is bolted to the cathode cover via cathode terminals. The cell cover is then fastened to the cell body with bolts or clamps. Fluoroplastic or fluororubber insulation seals are used between the anode and cathode terminals and the cell cover, and between the cell cover and the cell body. In NF3 production, the nickel anode corrodes and dissolves, leading to its continuous consumption. Therefore, the anode needs to be replaced after a period of operation. Both designs require terminating electrolysis and replacing the cell cover with a new anode when replacing the anode. Therefore, the anode's lifespan is one of the factors limiting the number of days the electrolytic cell can operate.

[0004] During the NF3 electrolysis process using nickel as the electrode, the nickel anode will corrode and dissolve to form NiF2 or NiF3. NiF2 or NiF3 will then react with NH4 in the electrolyte. + Ion complexation forms [NH4] + NiF3, [NH4] + ]4NiF6、[NH4 +The three types of electrolytic solid waste, namely 6NiF9, have a density greater than that of NH3·xHF molten salt electrolyte and will deposit at the bottom of the electrolytic cell. As electrolysis time increases, the amount of electrolytic solid waste in the cell increases. This has two main effects: first, it can bury the anode and cathode, causing abnormal current drops, and in severe cases, electrode short circuits; second, the increased amount of electrolytic solid waste suspended in the electrolyte alters the drift angle of the anode and cathode gases, potentially causing explosive mixing and other abnormal noises. Therefore, the amount of electrolytic solid waste deposited due to nickel anode corrosion and dissolution is the second factor limiting the operating days of the electrolytic cell.

[0005] To address the limitation on the number of days an electrolytic cell can operate due to nickel anodes, modified carbon anodes and diamond anodes based on carbon anodes have been applied to NF3 electrolytic cells. While these solutions have resolved the issues of anode corrosion and the generation of electrolytic solid waste during NF3 electrolysis, they have not solved the problems of low current density, carbon plate breakage, and excessive CF4. Therefore, NF3 industrial production uses electrolytic cells with nickel anodes.

[0006] Currently, to extend the service life of NF3 electrolyzers, two methods are generally used: thickening the nickel anode and deepening the electrolyzer, which increases the investment cost. Furthermore, during the dismantling process at the end of the NF3 electrolyzer's service life, the electrolyte containing electrolytic solids will deposit in the raw material tank during reuse, requiring the raw material tank to be dismantled and cleaned. Frequent dismantling of the electrolyzer also brings the following problems: 1) Both the electrolyte and electrolytic solid waste contain HF, increasing the probability of safety and occupational health risks for personnel, including but not limited to HF burns and occupational diseases such as fluorosis; 2) Electrolytic solid waste and wastewater from cleaning the electrolyzer are both hazardous waste containing fluoride, and frequent dismantling poses environmental risks; 3) After dismantling and reinstalling the electrolyzer, a low-current process is required for collection, which reduces the efficiency of the electrolyzer's operating time and increases operating costs.

[0007] Therefore, a production apparatus and its application for the long-term continuous electrolytic preparation of nitrogen trifluoride gas are proposed to solve the above problems. Summary of the Invention

[0008] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing a production apparatus and application for the long-term continuous electrolytic production of nitrogen trifluoride gas. This apparatus divides the tank cover into an anode cover and a cathode cover, and the anode gas outlet into an electrolytic gas outlet and an inert gas outlet. Each set of anodes and cathodes is connected to a conductive busbar using conductive wires. When the anode needs to be replaced, the conductive wires between the anode and cathode are disconnected, stopping electrolysis for that set of anodes and cathodes. The electrolytic gas outlet is closed, and the inert gas outlet is opened, allowing inert gas to be introduced into the anode and cathode gas phase regions. This removes residual anode gas from the anode region and dilutes the hydrogen concentration in the cathode gas phase region. After a period of inert gas input, the input is stopped, the anode cover with the old anode is removed, and the anode cover with the new anode is installed. The conductive wires are then connected, enabling continuous operation of NF3 electrolysis.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a production device for the long-term continuous electrolytic preparation of nitrogen trifluoride gas, comprising a raw material tank, a first pump body, an electrolytic cell, a settling tank, a second pump body, a filter, a collection tank and a third pump body connected in sequence by pipelines, wherein the third pump body is also connected to the top of the raw material tank;

[0010] The electrolytic cell includes a cell body, within which multiple sets of electrode electrolytic cells are arranged. Each set of electrode electrolytic cells includes a cathode cover, with two anode covers located in the middle of the cathode cover. Each anode cover has a gas outlet pipe extending through one end and an anode inert gas inlet extending through the other end. The side wall of the gas outlet pipe has an anode electrolytic gas outlet and an anode inert gas outlet. The cathode cover has a cathode outlet port extending through one end and a cathode inert gas inlet extending through the other end. Each anode cover has multiple anode terminals extending through it. The lower end of all anode terminals is connected to an anode plate, and the upper end of each anode terminal is connected to an anode conductive wire. All anode conductive wires are connected to an anode conductive busbar. The cathode cover has multiple cathode terminals extending through it. The lower end of all cathode terminals is connected to a cathode plate, and the upper end of each cathode terminal is connected to a cathode conductive wire. All cathode conductive wires are connected to a cathode conductive busbar. The cathode covers of the multiple sets of electrode electrolytic cells are located at the upper end of the cell body.

[0011] Preferably, the lower end of the cathode cover is provided with a skirt plate, which separates the anode plate and the cathode plate.

[0012] Preferably, the upper end of the outlet pipe is sealed; a first insulating sealing gasket is provided between the anode cover and the cathode cover, and a second insulating sealing gasket is provided between the cathode cover and the tank body; both the first insulating sealing gasket and the second insulating sealing gasket are fluoroplastics or fluororubber.

[0013] Preferably, an anode insulating sealing gasket is provided between each anode terminal and the anode cover; and a cathode insulating sealing gasket is provided between each cathode terminal and the cathode cover.

[0014] Preferably, the electrolytic cell is in the shape of a slender cuboid, with an electrolyte inlet at the bottom of one long outer wall and an electrolyte outlet at the bottom of the other long outer wall.

[0015] Preferably, the width of the electrolytic cell is 500mm to 3000mm.

[0016] Preferably, the first pump body, the second pump body, and the third pump body are all centrifugal pumps, canned pumps, magnetic pumps, or diaphragm pumps.

[0017] The application of the above-mentioned production apparatus for the long-term continuous electrolytic preparation of nitrogen trifluoride gas is also provided, and the application steps are as follows:

[0018] The electrolyte is stored in a raw material tank; the first pump adds the electrolyte from the raw material tank to the electrolytic tank, where the electrolyte undergoes electrolysis to produce NF3 gas, yielding residual electrolyte; the residual electrolyte is then transported from the bottom of the electrolytic tank to a settling tank, where the solids in the residual electrolyte settle naturally; the second pump then transports the electrolyte from the upper part of the settling tank to a filter for filtration, yielding clarified electrolyte; the clarified electrolyte flows into a collection tank, and the third pump transports the clarified electrolyte from the collection tank back to the raw material tank.

[0019] Preferably, the electrolyte is added to the electrolytic cell at a rate of 15 kg / kAh to 60 kg / kAh.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention utilizes an NF3 electrolysis device with a tank cover consisting of an anode cover and a cathode cover. The anode gas outlet is divided into an electrolytic gas outlet and an inert gas outlet. Conductive wires connect each set of anodes and cathodes to a conductive busbar. When the anode needs to be replaced, the conductive wire between the anode and cathode is disconnected, stopping electrolysis for that set of anodes and cathodes. The anode electrolytic gas outlet is closed, and the anode inert gas outlet is opened, allowing inert gas to be introduced into the anode and cathode gas phase regions. This removes residual anode gas from the anode region and dilutes the hydrogen concentration in the cathode gas phase region. After a period of inert gas input, the input is stopped, the anode cover with the old anode is removed, and the anode cover with the new anode is installed. The conductive wires are then connected, enabling continuous operation of NF3 electrolysis and solving the problem of limited electrolysis operating days caused by nickel anode dissolution and corrosion.

[0022] 2. This invention utilizes the power of a pump to cause the electrolyte to enter and exit from the bottom of the electrolytic cell, creating a bottom-flowing electrolyte that carries away electrolytic solid waste. New electrolyte is continuously injected into the electrolytic cell, solving the problem of suspended and deposited electrolytic solid waste during NF3 electrolysis. The electrolyte containing electrolytic solid waste flowing out of the electrolytic cell flows into a settling tank, where it settles to the bottom due to gravity, completing the first electrolyte purification. It then passes through a filter to further remove the electrolytic solid waste, completing the second electrolyte purification. The purified electrolyte is collected and returned to the raw material tank. After adjusting the HF / NH3 ratio, it is reused in the electrolytic cell. The electrolytic solid waste in the settling tank and the filter is collected and treated centrally. This method reduces the labor intensity, safety, environmental, and occupational health risks associated with frequent dismantling of the electrolytic cell, and eliminates the dismantling work required when injecting electrolyte containing electrolytic solid waste into the raw material tank.

[0023] 3. This invention utilizes electrolyte circulation to achieve self-purification, solving the problem of electrolysis termination due to the deposition of electrolytic solid waste in the electrolyte in traditional electrolytic cells; at the same time, this invention can directly replace the anode, solving the problem of electrolysis termination due to anode expiration in traditional electrolytic cells, and ultimately achieving continuous production of nitrogen trifluoride gas for more than one year for a single nitrogen trifluoride electrolytic cell.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the production apparatus of the present invention.

[0026] Figure 2 and Figure 3 This is a front view schematic diagram of the single-electrode electrolytic cell in this invention.

[0027] Figure 4 This is a side view of the single-electrode electrolytic cell in this invention.

[0028] Figure 5 This is a schematic diagram of the electrolyte entering and exiting the electrolytic cell in this invention.

[0029] Figure 6 This is a schematic diagram of the structure of the multi-electrode electrolytic cell connected to the conductive busbar in this invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1—Raw material tank; 2—First pump body; 3—Electrolytic cell; 301—Tank body; 302—Anode cover; 303—Cathode cover; 304—Anode inert gas inlet; 305—Anode electrolytic gas outlet; 306—Anode inert gas outlet; 307—Cathode outlet; 308—Cathode inert gas inlet; 309—Anode terminal block; 310—Anode plate; 311—Anode conductive wire; 312—Anode conductive busbar; 313—Cathode Terminal block; 314—Cathode plate; 315—Cathode conductive wire; 316—Cathode conductive busbar; 317—First insulating gasket; 318—Second insulating gasket; 319—Electrolyte inlet; 320—Electrolyte outlet; 321—Long side outer wall; 322—Skirt plate; 323—Anode insulating gasket; 324—Cathode insulating gasket; 4—Sedimentation tank; 5—Second pump body; 6—Filter; 7—Collection tank; 8—Third pump body. Detailed Implementation

[0032] Example 1

[0033] The production apparatus for the long-term continuous electrolytic preparation of nitrogen trifluoride gas in this embodiment includes a raw material tank 1, a first pump body 2, an electrolytic cell 3, a sedimentation tank 4, a second pump body 5, a filter 6, a collection tank 7 and a third pump body 8 connected in sequence by pipelines. The third pump body 8 is also connected to the top of the raw material tank 1.

[0034] The electrolytic cell 3 includes a cell body 301, within which three sets of electrode electrolytic cells are arranged. Each set of electrode electrolytic cells includes a cathode cover 303. Two anode covers 302 are disposed in the middle of the cathode cover 303. Each anode cover 302 has a gas outlet pipe extending through one end and an anode inert gas inlet 304 extending through the other end. An anode electrolytic gas outlet 305 and an anode inert gas outlet 306 are disposed on the side wall of the gas outlet pipe. A cathode outlet 307 is disposed through one end of the cathode cover 303, and a cathode inert gas inlet 308 extends through the other end. Two anode terminals 309 are disposed through each anode cover 302. The lower ends of all anode terminals 309 are connected to an anode plate 310. The upper end of each anode terminal 309 is connected to an anode conductive wire 311, and all anode conductive wires 311 are connected to an anode conductive busbar 312. Four cathode terminals 313 are provided through each cathode cover 303, and the lower end of each cathode terminal 313 is connected to a cathode plate 314. The upper end of each cathode terminal 313 is connected to a cathode conductive wire 315, and all cathode conductive wires 315 are connected to a cathode conductive busbar 316. The cathode covers 303 of the three electrode electrolysis cells are collectively located at the upper end of the cell body 301. A skirt plate 322 is provided at the lower end of the cathode cover 303, and the skirt plate 322 is located between the anode plate 310 and the cathode plate 314, separating the anode plate 310 and the cathode plate 314.

[0035] In this embodiment, the upper end of the outlet pipe is sealed; a first insulating sealing gasket 317 is provided between the anode cover 302 and the cathode cover 303, and a second insulating sealing gasket 318 is provided between the cathode cover 303 and the tank body 301; both the first insulating sealing gasket 317 and the second insulating sealing gasket 318 are fluoroplastics or fluororubber; an anode insulating sealing gasket 323 is provided between each anode terminal 309 and the anode cover 302; a cathode insulating sealing gasket 324 is provided between each cathode terminal 313 and the cathode cover 303; the first pump body 2, the second pump body 5, and the third pump body 8 are all centrifugal pumps, canned pumps, magnetic pumps, or diaphragm pumps;

[0036] The electrolytic cell 3 is a slender cuboid. An electrolyte inlet 319 is provided at the bottom of one long outer wall 321 of the electrolytic cell 3, and an electrolyte outlet 320 is provided at the bottom of the other long outer wall 321 of the electrolytic cell 3. The width of the electrolytic cell 3 is 500mm to 3000mm. When the width of the electrolytic cell 3 is greater than 3000mm, firstly, the electrolyzed solid waste cannot be carried out from the inside of the electrolytic cell 3; secondly, the size of a single set of anodes is too large, which is not conducive to replacement during electrolysis operation and is prone to sealing and insulation failure. When the width of the electrolytic cell 3 is less than 500mm, the electrolytic cell 3 is elongated, the electrode / cell volume ratio is low, and the cost will increase.

[0037] The application steps of the production apparatus for the long-term continuous electrolysis preparation of nitrogen trifluoride gas in this embodiment are as follows:

[0038] S1. The electrolyte is stored in the raw material tank 1; the electrolyte is NH3·xHF molten salt, prepared by mixing NH4HF2 and HF, or NH4F and HF, or NH3 and HF.

[0039] S2. The electrolyte in the raw material tank 1 is transported to the electrolytic cell 3 by the first pump body 2. The electrolyte undergoes an electrolytic reaction in the electrolytic cell 3 to generate NF3 gas, and the remaining electrolyte is obtained. The steps for replacing the anode without stopping electrolysis are as follows: disconnect the cathode conductive wire 315 from the cathode terminal 313; disconnect the anode conductive wire 311 from the anode terminal 309; input inert gas from the cathode inert gas inlet 308; close the anode electrolytic gas outlet 305; open the anode inert gas outlet 306 and input inert gas from the anode inert gas inlet 304; input inert gas for 15 min to 60 min, close the anode inert gas inlet 304 and the anode inert gas outlet 306; remove the anode cover 302 with the old anode plate 310; install the anode cover 302 with the new anode plate 310; open the anode electrolytic gas outlet 305, close the cathode inert gas inlet 308, and connect the anode conductive wire 311.

[0040] S3. Then the remaining electrolyte in the electrolytic cell 3 is transported from the bottom of the electrolytic cell 3 to the settling tank 4 through the electrolyte inlet 319 and the electrolyte outlet 320.

[0041] S4. Most of the electrolytic solid waste in the remaining electrolyte settles naturally in the settling tank 4. The electrolyte in the upper part of the settling tank 4 is transported to the filter 6 for filtration by the second pump body 5. The electrolyte after the settling process passes through the filter 6, and the remaining electrolytic solid waste is intercepted in the filter 6 through the filter screen to obtain clear electrolyte.

[0042] S5. The electrolyte solution obtained in S4 is collected in the collection tank 7 to remove the electrolyte from the electrolytic solid waste.

[0043] S6. The electrolyte in the collection tank 7 is transported to the raw material tank 1 by the third pump body 8 for recycling.

[0044] The electrolyte replenishment rate in S2 to the electrolytic cell 3 is 15 kg / kAh to 60 kg / kAh. If the electrolyte replenishment rate is too low (<15 kg / kAh), firstly, the consumed electrolyte cannot be replenished in time, and secondly, the generated electrolytic solid waste cannot be carried out of the electrolytic cell from the bottom. If the electrolyte replenishment rate is too fast (>60 kg / kAh), H2 in the electrolytic cell will drift to the anode area, posing a safety hazard.

[0045] Nitrogen trifluoride gas was prepared using the production apparatus of this embodiment: Electrolytic cell 3 has a capacity of 15 kA. The inert gas introduced into electrolytic cell 3 is N2. The electrolyte is a molten salt prepared by mixing HF and NH3 in a molar ratio of 2.6:1. The electrolysis current is 14300 A. The gas content in the anode region is 0.21% H2, 65.4% NF3, 31.2% N2, and 15.5 ppm CF4. The electrolyte is continuously added to electrolytic cell 3 from raw material tank 1, entering through electrolyte inlet 319 and exiting through electrolyte outlet 320 into settling tank 4. Electrolytic cell 3 has a width of 1500 mm and an electrolyte flow rate of 30 kg / kAh. After 85 days of operation, the electrolysis current decreased to 13400 A. A. Begin the gradual replacement of the anode. Close the anode electrolytic gas outlet 305, remove the anode conductive wire 311 and the corresponding cathode conductive wire 315 from the individual anode cover 302, open the anode inert gas inlet 304 and the cathode inert gas inlet 308 (N2), open the anode inert gas (N2) outlet 306, purge for 30 minutes, stop the anode N2 purging, close the anode inert gas (N2) outlet 306, remove the anode cover 302, install the anode cover 302 with the new anode, stop the cathode N2 purging, open the anode electrolytic gas outlet 305, connect the anode conductive wire 311 and the cathode conductive wire 315, replace all anodes within 30 days, and the current will return to 15100A.

[0046] After 500 days of operation, electrolysis was terminated, and electrolytic cell 3 was dismantled. There was no electrolytic solid waste in electrolytic cell 3.

[0047] Comparative Example 1

[0048] The production apparatus of this comparative example is the same as that of Example 1, except that the electrolytic cell of this comparative example is an existing electrolytic cell.

[0049] The electrolytic cell in this comparative example is a 15kA electrolytic cell with the anode and cathode connected together on the cell cover. The electrolyte is a molten salt prepared by mixing HF and NH3 in a molar ratio of 2.6:1. The electrolysis current is 14000A, and a nickel anode is used. The gas content in the anode area is 0.15% H2, 64% NF3, and 33% N2. After 130 days of operation, the anode current dropped to 5000A. The electrolytic cell was then dismantled, the electrolytic solid waste was treated, the cell was cleaned, the anode was replaced, and the cell was reassembled. NF3 electrolysis was restarted for water removal. Once the collection conditions were met, the anode gas was collected. The total time for dismantling and installing the electrolytic cell and water removal was 10 days.

[0050] Comparative Example 2

[0051] The production apparatus of this comparative example is the same as that of Example 1, except that the electrolyte replenishment rate of this comparative example is 100 kg / kAh.

[0052] The electrolytic cell is a 15kA cell with N2 as the inert gas. It features a separate anode and cathode cover installation. The electrolyte is a molten salt prepared from HF and NH3 in a molar ratio of 2.6:1. The electrolysis current is 13500A. The gas content in the anode area is: H2 0.1%, NF3 62.4%, N2 34.2%, and CF4 20ppm. The electrolyte is continuously added to the electrolytic cell from the feed tank, entering from one side of the long side and exiting from the other side into the settling tank. The electrolytic cell is 1000mm wide, and the electrolyte flow rate is 100kg / kAh. After 90 days of operation, the H2 content in the anode area fluctuates between 0.5% and 2.5%, accompanied by continuous popping sounds, at which point electrolysis is terminated.

[0053] Comparative Example 3

[0054] The production apparatus of this comparative example is the same as that of Example 1, except that the electrolyte replenishment rate of this comparative example is 10 kg / kAh.

[0055] The electrolytic cell is a 15kA electrolytic cell with N2 as the inert gas. It adopts a structure in which the anode cover and cathode cover are installed separately. The electrolyte is a molten salt prepared by adjusting HF and NH3 in a molar ratio of 2.6:1. The electrolysis current is 14500A. The gas content in the anode area is 0.15% H2, 63.4% NF3, 32.2% N2, and 17.5ppm CF4. Electrolyte was continuously added to the electrolytic cell from the raw material tank, entering from one side of the long side and exiting from the other side into the settling tank. The electrolytic cell was 4000 mm wide, and the electrolyte flow rate was 10 kg / kAh. After 90 days of operation, the electrolytic current dropped to 13000 A, and the anode replacement operation was started gradually. The anode electrolytic gas outlet was closed, the anode conductive wire and the corresponding cathode wire of the individual anode cover were removed, the anode and cathode N2 inlets were opened, the anode N2 outlet was opened, and the anode N2 purging was carried out for 30 minutes. The anode N2 purging was stopped, the anode N2 outlet was closed, the anode cover was removed, and an anode cover with a new anode was installed. The cathode N2 purging was stopped, the anode electrolytic gas outlet was opened, and the anode and cathode conductive wires were connected. All anodes were replaced within 30 days, and the current recovered to 14800 A.

[0056] After 230 days of operation, the accumulated electrolytic solid waste on the electrolyte outlet side of the electrolytic cell buried the anode and cathode, causing a short circuit. This resulted in an abnormal phenomenon where the current suddenly surged to 17,000A and a loud bang occurred, terminating the electrolysis.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A production apparatus for long-term continuous electrolytic production of nitrogen trifluoride gas, characterized by comprising: It comprises a raw material tank (1), a first pump body (2), an electrolytic tank (3), a settling tank (4), a second pump body (5), a filter (6), a collection tank (7) and a third pump body (8) connected by pipelines in sequence, and the third pump body (8) is also connected with the top of the raw material tank (1); The electrolytic tank (3) comprises a tank body (301), a plurality of groups of electrode electrolytic tanks are arranged in the tank body (301), a single group of the electrode electrolytic tank comprises a cathode cover (303), two anode covers (302) are arranged on the middle part of the cathode cover (303), an air outlet pipe is arranged on one end of each of the anode covers (302) in penetrating mode, an anode inert gas inlet (304) is arranged on the other end of each of the anode covers (302) in penetrating mode, an anode electrolytic gas outlet (305) and an anode inert gas outlet (306) are arranged on the side wall of the air outlet pipe, a cathode air outlet (307) is arranged on one end of the cathode cover (303) in penetrating mode, a cathode inert gas inlet (308) is arranged on the other end of the cathode cover (303) in penetrating mode, a plurality of anode terminal posts (309) are arranged on each of the anode covers (302) in penetrating mode, the lower ends of all the anode terminal posts (309) are connected with an anode plate (310) in common, the upper ends of each of the anode terminal posts (309) are connected with an anode conductive wire (311), and all the anode conductive wires (311) are connected with an anode conductive busbar (312) in common, a plurality of cathode terminal posts (313) are arranged on the cathode cover (303) in penetrating mode, the lower ends of all the cathode terminal posts (313) are connected with a cathode plate (314) in common, the upper ends of each of the cathode terminal posts (313) are connected with a cathode conductive wire (315), and all the cathode conductive wires (315) are connected with a cathode conductive busbar (316) in common, and the cathode covers (303) of the plurality of groups of electrode electrolytic tanks are arranged on the upper end of the tank body (301) in common. The electrolytic tank (3) is in the shape of an elongated cuboid, the bottom of one long side outer wall (321) of the electrolytic tank (3) is provided with an electrolyte inlet (319), and the bottom of the other long side outer wall (321) of the electrolytic tank (3) is provided with an electrolyte outlet (320).

2. The production apparatus according to claim 1, characterized by The lower end of the cathode cover (303) is provided with a skirt plate (322), and the skirt plate (322) separates the anode plate (310) and the cathode plate (314).

3. The production apparatus according to claim 1, characterized by The upper end of the air outlet pipe is sealed, a first insulating sealing gasket (317) is arranged between the anode cover (302) and the cathode cover (303), and a second insulating sealing gasket (318) is arranged between the cathode cover (303) and the tank body (301); the first insulating sealing gasket (317) and the second insulating sealing gasket (318) are fluoroplastic or fluororubber.

4. The production apparatus according to claim 1, characterized by An anode insulating sealing gasket (323) is arranged between each of the anode terminal posts (309) and the anode cover (302), and a cathode insulating sealing gasket (324) is arranged between each of the cathode terminal posts (313) and the cathode cover (303).

5. The production apparatus according to claim 1, wherein, The width of the electrolytic tank (3) is 500mm-3000mm.

6. The production apparatus according to claim 1, wherein The first pump body (2), the second pump body (5) and the third pump body (8) are centrifugal pumps, shield pumps, magnetic force pumps or diaphragm pumps.

7. Use of the long-term continuous electrolysis apparatus for producing a nitrogen trifluoride gas as claimed in claim 1, characterized in that, The application steps are as follows: The electrolyte is stored in the raw material tank (1); the electrolyte in the raw material tank (1) is supplemented into the electrolysis tank (3) by the first pump body (2), the electrolysis of the electrolyte in the electrolysis tank (3) produces NF3 gas, and the remaining electrolyte is obtained; then the remaining electrolyte in the electrolysis tank (3) is transported from the bottom of the electrolysis tank (3) to the sedimentation tank (4), the solid substances in the remaining electrolyte naturally settle in the sedimentation tank (4), and then the electrolyte in the upper part of the sedimentation tank (4) is transported to the filter (6) for filtration by the second pump body (5), and the electrolyte supernatant is obtained; the electrolyte supernatant flows into the collection tank (7), and the electrolyte supernatant in the collection tank (7) is transported into the raw material tank (1) by the third pump body (8).

8. Use of a long-term continuous electrolysis production apparatus for producing nitrogen trifluoride gas according to claim 7, characterized in that The rate of supplementing the electrolyte into the electrolysis tank (3) is 15 kg / kAh~60 kg / kAh.

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