Method and apparatus for recovering spent electrolyte from a nitrogen trifluoride electrolytic cell

Abstract

The application provides a recovery method of waste electrolyte in a nitrogen trifluoride electrolytic tank, which comprises the following steps: after the nitrogen trifluoride electrolytic tank stops electrolysis, the obtained waste electrolyte and paste-like deposit are introduced into a storage tank and are left to stand, then the storage tank is heated, and an electromagnetic device is started to adsorb the metal elements in the paste-like deposit onto the inner wall of the storage tank by magnetic force, the metal fluoride is deposited at the bottom of the storage tank, and an upper layer liquid is obtained; the supernatant after centrifugation of the upper layer liquid is introduced into a mixing reaction kettle through a buffer tank, whether the supernatant is introduced into a transfer tank and used as electrolyte is determined by measuring the composition of the supernatant; and a recovery device used in the recovery method is also provided, which comprises a nitrogen trifluoride electrolytic tank, a storage tank, an electromagnetic device, a centrifuge, a buffer tank, a mixing reaction kettle and a transfer tank; the application realizes the recovery and reuse of the waste electrolyte mixed with the deposit in the nitrogen trifluoride electrolytic tank, and greatly reduces the input amount of nitrogen trifluoride raw materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nitrogen trifluoride preparation, and particularly relates to a method and device for recovering waste electrolyte in a nitrogen trifluoride electrolytic tank. BACKGROUND

[0002] The electrolytic production of nitrogen trifluoride (NF3) is a continuous process, which means that the electrolyte in the electrolytic tank is consumed at all times. In order to ensure the continuous production of nitrogen trifluoride, electrolyte needs to be added according to the consumption of the electrolyte.

[0003] The anode material for the electrolytic production of nitrogen trifluoride (NF3) is a transition metal plate. In the electrolysis process, the anode plate will be gradually consumed. The metal ions released by electrolysis will be electroplated onto the cathode plate, and the metal elements on the electroplated plate have weak adhesion. With the increase of time, most of them will fall off into the electrolyte. In addition, due to the presence of anhydrous hydrogen fluoride in the raw material, the cathode plate and the falling over metal element slag will also be chemically corroded to form metal fluoride. Both the metal element and the metal fluoride have a large specific gravity, which will cause most of them to deposit at the bottom of the electrolytic tank, affecting the electrolytic removal of heat, the electrolysis efficiency and the quality of the nitrogen trifluoride gas. In order to minimize the impact of these factors in the electrolysis, the deposits in the electrolytic tank must be cleaned regularly to maintain high efficiency and high yield of electrolysis gas production.

[0004] The cleaned deposits are currently directly treated by a three-waste treatment process. In addition to metal elements and metal fluorides, the deposits also contain about 70% of waste electrolyte (electrolytic raw materials such as ammonium bifluoride and hydrogen fluoride that do not participate in the electrolysis reaction, with a weight of (0.7-1.2) T per electrolytic tank). The waste electrolyte is also treated as a three-waste material, resulting in a great waste of electrolytic raw materials. Therefore, a waste electrolyte recovery process and device are proposed to solve the above problems. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a waste electrolyte recovery method and device, which can recycle the waste electrolyte mixed in the deposits in the nitrogen trifluoride electrolytic tank, greatly reduce the input amount of nitrogen trifluoride raw materials, reduce the input cost, help reduce the pressure of three-waste treatment, and is more in line with environmental protection requirements and has strong practicality.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a method for recovering waste electrolyte in a nitrogen trifluoride electrolytic tank, which comprises the following steps:

[0007] S1, after the nitrogen trifluoride electrolytic tank stops electrolysis, waste electrolyte and mud paste-like deposits are obtained, nitrogen gas with a pressure of 0.15-0.2 MPa is filled into the gas phase space of the nitrogen trifluoride electrolytic tank, and the waste electrolyte and mud paste-like deposits are pressed into a storage tank;

[0008] S2, after the waste electrolyte and mud paste-like deposits in S1 are left to stand in the storage tank, the storage tank is heated to a temperature of 80-130 DEG C, then the switch of the electromagnetic device is turned on, and the metal elements in the mud paste-like deposits are adsorbed to the inner side wall of the storage tank by magnetic force, the metal fluoride in the mud paste-like deposits is deposited at the bottom of the storage tank, and an upper layer of liquid is obtained;

[0009] S3, the upper layer of liquid obtained in S2 is pumped into a centrifuge for centrifugation to remove metal slag and metal oxides, and a supernatant is obtained, which is buffered in a buffer tank and then enters a mixing reaction kettle;

[0010] S4, when the supernatant in the mixing reaction kettle in S3 reaches a specified liquid level, the ammonia gas is stopped, the supernatant in the mixing reaction kettle is tested, when the mass ratio of ammonium fluoride to hydrogen fluoride in the supernatant is < (6-12) : 1, ammonia gas is introduced into the mixing reaction kettle, and the temperature of the mixing reaction kettle is controlled at 80-100 DEG C, until the mass ratio of ammonium fluoride to hydrogen fluoride in the supernatant is (6-12) : 1, and an electrolyte is obtained;

[0011] S5, nitrogen gas is introduced into the mixing reaction kettle, and the electrolyte obtained in S4 is pressed into a transfer tank;

[0012] S6, the electrolyte in the transfer tank in S5 is introduced into the nitrogen trifluoride electrolytic tank for continuous use.

[0013] Preferably, the flow rate of the nitrogen gas in S1 is 10000-15000 L / h, and the time is 0.25-0.3 h; the standing time in S2 is 8-12 h; and the magnetic force is 50-100 N / m 2 .

[0014] Preferably, the rotational speed of the centrifuge in S3 is 2000-2300 r / min, and the feeding speed of the mixing reaction kettle is 1000-1500 kg / h.

[0015] Preferably, the introduction speed of the ammonia gas in S4 is 50-120 kg / h; the introduction time of the ammonia gas is 0-8 h; and the specified liquid level is 3 / 4 of the mixing reaction kettle.

[0016] Preferably, the pressure of the nitrogen in S5 is 0.15-0.2 Mpa, and the time is 20-30 min; the speed of the electrolyte in the intermediate tank flowing into the nitrogen trifluoride electrolysis tank in S6 is 865-1730 kg / h; and the liquid level of the electrolyte in the intermediate tank flowing into the nitrogen trifluoride electrolysis tank is 530-560 mm.

[0017] Also provided is a recovery device for waste electrolyte in a nitrogen trifluoride electrolysis tank used in the above-mentioned recovery method, comprising a plurality of nitrogen trifluoride electrolysis tanks, a storage tank, an electromagnetic device, a centrifuge, a buffer tank, a mixing reaction kettle and an intermediate tank, the interior of each of the nitrogen trifluoride electrolysis tanks is divided into a gas phase space and a liquid phase space, the gas phase space is connected with the storage tank through a pressure pipe, the storage tank is arranged in the electromagnetic device, the upper end of the storage tank is connected with the centrifuge through a first pipeline, the centrifuge is connected with the buffer tank and the mixing reaction kettle in sequence through a pipeline, the outlet of the mixing reaction kettle is connected with the intermediate tank, and the intermediate tank is connected with the pressure pipe through a second pipeline.

[0018] Preferably, a diaphragm pump is installed on each of the first pipeline and the second pipeline; the upper end of the mixing reaction kettle is connected with an ammonia gas pipeline and a nitrogen gas pipeline respectively, one end of the ammonia gas pipeline extends into the mixing reaction kettle and is provided with a gas distributor with a pore diameter of 2-4 mm.

[0019] Preferably, one end of the pressure pipe extends into the interior of each of the nitrogen trifluoride electrolysis tanks, and the pipe opening of the pressure pipe is 3-6 cm away from the tank bottom in the nitrogen trifluoride electrolysis tank.

[0020] Preferably, the material of the storage tank is carbon steel, and seamless carbon steel pipes are arranged on the opposite two side walls of the storage tank; the electromagnetic device is a carbon steel storage tank; the material of the intermediate tank is carbon steel, and seamless carbon steel pipes are arranged on the opposite two side walls of the intermediate tank; and a heating pipe is arranged in the seamless carbon steel pipe.

[0021] Preferably, the centrifuge is a sedimentation type centrifuge, the interior material of which is Monel, the rotating speed of which is 1500-2500 r / min, and the separation factor of which is 755-1260; the material of the mixing reaction kettle is Monel, the interior of which is provided with a stirring device, and a jacket is arranged on the outer wall of the mixing reaction kettle, and water flows through the jacket.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] 1. The present application realizes the recovery and reuse of waste electrolyte with inclusions of deposits in the nitrogen trifluoride electrolysis tank, can greatly reduce the input amount of nitrogen trifluoride raw materials, realizes the reduction of input cost; in addition, this also means the reduction of three wastes, helps to reduce the treatment pressure of three wastes, is more in line with the environmental protection requirements, and has strong practicability.

[0024] 2. Through magnetic separation, settling and centrifugation processes, the sediment in the electrolytic cell can be effectively separated. The sediment separated by the storage tank and centrifuge is recycled using a metal resource recovery process, reducing the weight loss of waste electrolyte per electrolytic cell from (0.7~1.2)T to (0.1~0.2)T.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the recycling device of the present invention.

[0027] Explanation of reference numerals in the attached drawings: 1—Nitrogen trifluoride electrolytic cell; 2—Storage tank; 3—Electromagnetic equipment; 4—Centrifuge; 5—Buffer tank; 6—Mixing reactor; 7—Transfer tank. Detailed Implementation

[0028] Example 1

[0029] The method for recovering waste electrolyte from a nitrogen trifluoride electrolyzer provided in this embodiment includes the following steps:

[0030] S1. After the nitrogen trifluoride electrolyzer operates for 100 days and electrolysis is stopped, waste electrolyte and sludge-like sediment are obtained. Nitrogen gas at a pressure of 0.15 MPa is introduced into the gas phase space of the nitrogen trifluoride electrolyzer to pressurize the waste electrolyte and sludge-like sediment into a storage tank. The flow rate of the nitrogen gas is 10000 L / h, and the time is 0.3h. The waste electrolyte includes unreacted ammonium hydrogen fluoride and hydrogen fluoride. The sludge-like sediment includes elemental nickel and iron compounds, as well as impurities such as hydrogen fluoride.

[0031] After the waste electrolyte and sludge-like sediment described in S2 and S1 are left to stand in the storage tank for 8 hours, the storage tank is heated to 80°C. Then, the electromagnetic device is switched on, and the elemental metals in the waste electrolyte are attracted to the inner wall of the storage tank by magnetic force. Metal fluorides are deposited at the bottom of the storage tank, resulting in the upper layer of liquid. The magnetic force is 50 N / m. 2 Heating the storage tank is to maintain the liquid state of the substance inside the tank, so that the contained elemental metals will float or settle at the bottom, which is conducive to adsorption on the inner wall of the storage tank; the elemental metals are nickel and iron, and the metal fluorides are nickel fluoride and iron fluoride;

[0032] S3, the supernatant obtained in S2 is pumped into a centrifuge for centrifugation, the centrifuge has a rotating speed of 2000 r / min, metal slag and metal oxide are removed, and supernatant is obtained, the supernatant is introduced into a buffer tank for buffering, and then introduced into a mixing reaction kettle at a feeding speed of 1000 kg / h; the metal slag is nickel and iron single elements, and the metal oxide is a nickel-iron compound; the supernatant is ammonium bifluoride and hydrogen fluoride molten liquid;

[0033] S4, when the electrolyte in the mixing reaction kettle in S3 reaches 3 / 4 of the mixing reaction kettle, the introduction is stopped, and the supernatant in the mixing reaction kettle is tested by acid-base titration method, when the mass ratio of ammonium bifluoride and hydrogen fluoride in the supernatant is (6-12):1, the introduction time of ammonia gas is 0 h, and the electrolyte is obtained;

[0034] S5, nitrogen gas with a pressure of 0.15 Mpa is introduced into the mixing reaction kettle for 30 min, and the electrolyte obtained in S4 is pressed into a transfer tank;

[0035] S6, the electrolyte in the transfer tank in S5 is introduced into the nitrogen trifluoride electrolysis tank at a speed of 865 kg / h until the liquid level is 530 mm, and continues to be used.

[0036] The mass ratio of ammonium bifluoride and hydrogen fluoride in the supernatant in S4 can be 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1 or 12:1.

[0037] Example 2

[0038] The method for recycling waste electrolyte in the nitrogen trifluoride electrolysis tank provided in the embodiment comprises the following steps:

[0039] S1, after the nitrogen trifluoride electrolysis tank is stopped for electrolysis for 80 days, waste electrolyte and paste-like deposits are obtained, nitrogen gas with a pressure of 0.18 Mpa is filled into the gas phase space of the nitrogen trifluoride electrolysis tank, and the waste electrolyte and paste-like deposits are introduced into a storage tank; the flow rate of the nitrogen gas is 15000 L / h, and the time is 0.25 h; the waste electrolyte includes ammonium bifluoride and hydrogen fluoride which do not participate in the reaction; the paste-like deposits include nickel, iron single elements and compounds, and impurities such as hydrogen fluoride;

[0040] S2, after the waste electrolyte and paste-like deposits in S1 are statically placed in the storage tank for 10 h, the storage tank is heated to a temperature of 100℃, then the switch of the electromagnetic device is turned on, the metal single elements in the waste electrolyte are adsorbed to the inner side wall of the storage tank by magnetic force, and the metal fluoride is deposited at the bottom of the storage tank, and the supernatant is obtained; the magnetic force is 70 N / m 2The storage tank is heated to maintain the liquid state of the material in the tank, and the metal elements float or deposit at the bottom, which is beneficial to adsorption on the inner side wall of the storage tank; the metal elements are nickel elements and iron elements, and the metal fluoride is nickel fluoride and iron fluoride;

[0041] S3, the upper liquid in S2 is extracted into a centrifuge with a speed of 2200 r / min to remove metal slag and metal oxide, and the supernatant is obtained, and the supernatant is introduced into a buffer tank for buffering, and then introduced into a mixing reaction kettle at a feeding speed of 1300 kg / h; the metal slag is nickel element and iron element, and the metal oxide is nickel-iron compound; the supernatant is ammonium bifluoride and hydrogen fluoride molten liquid;

[0042] S4, when the supernatant in the mixing reaction kettle in S3 reaches 3 / 4 of the mixing reaction kettle, stop introducing, and test the supernatant in the mixing reaction kettle by acid-base titration method, when the mass ratio of ammonium bifluoride and hydrogen fluoride in the supernatant is less than (6-12):1, introduce ammonia gas into the mixing reaction kettle, the introduction speed of the ammonia gas is 120 kg / h; the introduction time of the ammonia gas is 4h, and the temperature of the mixing reaction kettle is controlled at 90℃, until the mass ratio of ammonium bifluoride and hydrogen fluoride in the supernatant is (6-12):1, to obtain an electrolyte; an exothermic reaction occurs during the introduction of ammonia gas, and the reaction equation is: 2HF+NH3→NH4HF2+118kJ / mol;

[0043] S5, introduce nitrogen gas with a pressure of 0.2Mpa into the mixing reaction kettle for 20min, and press the electrolyte obtained in S4 into a transfer tank;

[0044] S6, introduce the electrolyte in the transfer tank in S5 into the nitrogen trifluoride electrolysis tank at a speed of 1000 kg / h until the liquid level is 550mm, and continue to use.

[0045] In this embodiment, the introduction speed of ammonia gas in S4 can also be 50kg / h, 60kg / h, 70kg / h, 80kg / h, 90kg / h, 100kg / h, 105kg / h or 115kg / h, and the introduction time can also be 1h, 2h, 3h, 5h, 6h, 7h or 7.5h; the temperature of the mixing reaction kettle can also be 80℃, 85℃, 95℃, 97℃, 110℃, 120℃, 125℃ or 130℃.

[0046] Example 3

[0047] The method for recycling waste electrolyte in the nitrogen trifluoride electrolysis tank provided in this embodiment comprises the following steps:

[0048] S1, after the electrolysis of the nitrogen trifluoride electrolytic tank 90 days is stopped, the waste electrolyte and the paste-like deposit are obtained, nitrogen gas with a pressure of 0.2 Mpa is filled into the gas phase space of the nitrogen trifluoride electrolytic tank, and the waste electrolyte and the paste-like deposit are introduced into a storage tank; the flow rate of the nitrogen gas is 13000 L / h, and the time is 0.27 h; the waste electrolyte includes ammonium fluoride and hydrogen fluoride which do not participate in the reaction; the paste-like deposit includes nickel, iron, and compounds and impurities such as hydrogen fluoride;

[0049] S2, after the waste electrolyte and the paste-like deposit in S1 are placed in the storage tank for 8-12 h, the storage tank is heated to a temperature of 130 DEG C, and then the switch of a magnetic device is turned on, so that the metal single element in the waste electrolyte is adsorbed to the inner side wall of the storage tank by magnetic force, and the metal fluoride is deposited at the bottom of the storage tank, to obtain an upper layer liquid; the magnetic force is 100 N / m 2 ; the storage tank is heated to maintain the substances in the tank in a liquid state, and the metal single element is floated or deposited at the bottom, which is beneficial to be adsorbed to the inner side wall of the storage tank; the metal single element is nickel and iron, and the metal fluoride is nickel fluoride and iron fluoride;

[0050] S3, the upper layer liquid obtained in S2 is pumped into a centrifuge for centrifugation, the rotating speed of the centrifuge is 2300 r / min, the metal slag and the metal oxide are removed, and a supernatant is obtained, which is introduced into a buffer tank for buffering, and then is introduced into a mixing reaction kettle at a feeding speed of 1500 kg / h; the metal slag is nickel and iron, the metal oxide is a nickel-iron compound, and the supernatant is a hydrogen fluoride and hydrogen fluoride melt;

[0051] S4, when the supernatant in the mixing reaction kettle in S3 reaches 3 / 4 of the mixing reaction kettle, the introduction is stopped, and the supernatant in the mixing reaction kettle is tested by an acid-base titration method, when the mass ratio of ammonium fluoride and hydrogen fluoride in the supernatant is <(6-12):1, ammonia gas is introduced into the mixing reaction kettle, the introduction speed of the ammonia gas is 110 kg / h, the introduction time of the ammonia gas is 8 h, and the temperature of the mixing reaction kettle is controlled to be 100 DEG C, until the mass ratio of ammonium fluoride and hydrogen fluoride in the supernatant is (6-12):1, to obtain an electrolyte; an exothermic reaction occurs in the process of introducing the ammonia gas, and the reaction equation is: 2HF+NH3→NH4HF2+118 kJ / mol;

[0052] S5, nitrogen gas with a pressure of 0.17 Mpa is introduced into the mixing reaction kettle for 25 min, and the electrolyte obtained in S4 is pressed into a transfer tank;

[0053] S6, electrolyte in the transfer tank in S5 is fed into the nitrogen trifluoride electrolytic tank at a speed of 1730 kg / h to a liquid level of 560 mm, and continues to be used.

[0054] Embodiment 4

[0055] The recovery device for waste electrolyte in the nitrogen trifluoride electrolytic tank in the recovery method of embodiments 1-3 comprises two nitrogen trifluoride electrolytic tanks 1, a storage tank 2, an electromagnetic device 3, a centrifuge 4, a buffer tank 5, a mixing reaction kettle 6 and a transfer tank 7, the inside of each of the nitrogen trifluoride electrolytic tanks 1 is divided into a gas phase space and a liquid phase space, the gas phase space is connected with the storage tank 2 through a pressure pipe, the liquid phase space is connected with a hydrogen fluoride pipeline, the storage tank 2 is arranged in the electromagnetic device 3, the upper end of the storage tank 2 is connected with the centrifuge 4 through a first pipeline, the centrifuge 4 is connected with the buffer tank 5 and the mixing reaction kettle 6 in sequence through a pipeline, the outlet of the mixing reaction kettle 6 is connected with the transfer tank 7, and the transfer tank 7 is connected with the pressure pipe through a second pipeline; a filter is further arranged between the buffer tank 5 and the mixing reaction kettle 6.

[0056] A diaphragm pump is mounted on each of the first pipeline and the second pipeline; the upper end of the mixing reaction kettle 6 is connected with an ammonia gas pipeline and a nitrogen gas pipeline respectively, one end of the ammonia gas pipeline extends into the mixing reaction kettle 6 and is provided with a gas distributor with a pore size of 2-4 mm; one end of the pressure pipe extends into the inside of each of the nitrogen trifluoride electrolytic tanks 1, and the distance between the pipe opening of the pressure pipe and the bottom of each of the nitrogen trifluoride electrolytic tanks 1 is 3-6 cm.

[0057] In this embodiment, seamless carbon steel pipes are arranged on the opposite two side walls of the storage tank 2; the electromagnetic device 3 is a carbon steel storage tank; the material of the transfer tank 7 is carbon steel, and seamless carbon steel pipes are arranged on the opposite two side walls of the transfer tank 7; a heating pipe is arranged in the seamless carbon steel pipe; the centrifuge 4 is a sedimentation type centrifuge, the inside of which is made of Monel, the rotating speed is 1500-2500 r / min, and the separation factor is 755-1260; the material of the mixing reaction kettle 6 is Monel, and a stirring device is arranged in the inside of the mixing reaction kettle 6; a jacket is arranged on the outer wall of the mixing reaction kettle 6, and water is circulated in the jacket.

[0058] The above description is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made according to the technical essence of the present application to the above embodiment are still within the protection scope of the technical solution of the present application.

Claims

1. A method for recovering waste electrolyte from a nitrogen trifluoride electrolyzer, characterized in that, The method includes the following steps: S1. After the nitrogen trifluoride electrolytic cell stops electrolysis, waste electrolyte and mud-like deposits are obtained. Nitrogen gas at a pressure of 0.15-0.2 MPa is introduced into the gas phase space of the nitrogen trifluoride electrolytic cell to press the waste electrolyte and mud-like deposits into the storage tank. After the waste electrolyte and mud-like sediment mentioned in S2 and S1 are left to stand in the storage tank, the storage tank is heated to a temperature of 80-130°C. Then, the switch of the electromagnetic device is turned on, and the metal element in the mud-like sediment is adsorbed onto the inner wall of the storage tank by magnetic force. The metal fluoride in the mud-like sediment is deposited at the bottom of the storage tank to obtain the upper layer liquid. S3. The upper liquid obtained in S2 is pumped into a centrifuge for centrifugation to remove metal slag and metal oxides, and a supernatant is obtained. The supernatant is then passed into a buffer tank for buffering before entering the mixing reactor. S4. When the supernatant in the mixing reactor mentioned in S3 reaches the specified liquid level, stop the flow and test the supernatant in the mixing reactor. When the mass ratio of ammonium bifluoride to hydrogen fluoride in the supernatant is < (6-12):1, ammonia gas is introduced into the mixing reactor and the temperature of the mixing reactor is controlled at 80-100℃ until the mass ratio of ammonium bifluoride to hydrogen fluoride in the supernatant is (6-12):1, and the electrolyte is obtained. S5. Nitrogen gas is introduced into the mixing reactor to pump the electrolytic liquid obtained in S4 into the transfer tank. S6. The electrolyte in the transfer tank mentioned in S5 is passed into the nitrogen trifluoride electrolytic cell for continued use.

2. The recycling method according to claim 1, characterized in that, The nitrogen flow rate in S1 is 10000–15000 L / h, and the time is 0.25–0.3 h; the settling time in S2 is 8–12 h; the magnetic force is 50–100 N / m. 2 .

3. The recycling method according to claim 1, characterized in that, The centrifuge in S3 has a rotation speed of 2000-2300 r / min, and the feed rate of the mixing reactor is 1000-1500 kg / h.

4. The recycling method according to claim 1, characterized in that, The ammonia gas introduction rate in S4 is 50-120 kg / h; the ammonia gas introduction time is 0-8 h; and the specified liquid level is 3 / 4 of the mixing reactor.

5. The recycling method according to claim 1, characterized in that, The nitrogen pressure in S5 is 0.15-0.2 MPa, and the time is 20-30 min; the rate at which the electrolyte in the transfer tank is introduced into the nitrogen trifluoride electrolytic cell in S6 is 865-1730 kg / h; and the liquid level of the electrolyte in the transfer tank introduced into the nitrogen trifluoride electrolytic cell is 530-560 mm.

6. The device for recovering waste electrolyte from a nitrogen trifluoride electrolyzer used in the recovery method according to any one of claims 1-5, characterized in that, The system includes multiple nitrogen trifluoride electrolyzers (1), storage tanks (2), electromagnetic equipment (3), centrifuges (4), buffer tanks (5), mixing reactors (6), and transfer tanks (7). Each nitrogen trifluoride electrolyzer (1) is divided into a gas phase space and a liquid phase space. The gas phase space is connected to the storage tanks (2) through a pressure pipe. The storage tanks (2) are located inside the electromagnetic equipment (3). The upper end of the storage tanks (2) is connected to the centrifuges (4) through a first pipeline. The centrifuges (4) is connected to the buffer tanks (5) and the mixing reactors (6) in sequence through pipelines. The outlet of the mixing reactors (6) is connected to the transfer tanks (7). The transfer tanks (7) are connected to the pressure pipes through a second pipeline.

7. The recycling device according to claim 6, characterized in that, Diaphragm pumps are installed on both the first and second pipelines; the upper end of the mixing reactor (6) is connected to an ammonia pipeline and a nitrogen pipeline respectively, one end of the ammonia pipeline extends into the mixing reactor (6) and is equipped with a gas distributor with an aperture of 2-4 mm.

8. The recycling device according to claim 6, characterized in that, One end of each pressing tube extends into the interior of each nitrogen trifluoride electrolytic cell (1), and the distance between the opening of the pressing tube and the bottom of each nitrogen trifluoride electrolytic cell (1) is 3 to 6 cm.

9. The recycling device according to claim 6, characterized in that, The storage tank (2) is made of carbon steel, and seamless carbon steel pipes are provided on the opposite side walls of the storage tank (2); the electromagnetic device (3) is a carbon steel storage tank; the transfer trough (7) is made of carbon steel, and seamless carbon steel pipes are provided on the opposite side walls of the transfer trough (7); a heating pipe is provided inside the seamless carbon steel pipe.

10. The recycling device according to claim 6, characterized in that, The centrifuge (4) is a sedimentation centrifuge with Monel as the internal material, a rotation speed of 1500-2500 r / min, and a separation factor of 755-1260. The mixing reactor (6) is made of Monel and has a stirring device inside. The outer wall of the mixing reactor (6) is equipped with a jacket, and water flows through the jacket.

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