A nitric acid evaporation device and process

Abstract

The present application provides a nitric acid evaporation device and process, belonging to the technical field of nitric acid evaporation, comprising an evaporator, a condenser connected to a steam discharge hole on the top of a side wall of the evaporator, a drain pipe arranged at the bottom of the condenser, and a microwave heater arranged inside the evaporator; an upper rotor is provided through the top wall of the evaporator in a rotating connection manner, a lower rotor is provided at the bottom of the upper rotor, and a slag discharge gap is reserved between the upper rotor and the lower rotor, a conical filter bucket matching the upper rotor and capable of blocking the slag discharge gap is vertically slidably connected inside the lower rotor, and a plurality of injection pipes are connected to the lower rotor; a slag collecting ring is provided inside the evaporator, and the slag collecting ring is connected to a slag discharge pipe connected to an external negative pressure air pump; a main hydraulic oil cylinder and a drive assembly are provided on the evaporator; the present application can reduce the possibility of nitric acid evaporation being interfered with by waste residues.

Description

Technical Field

[0001] The present application relates to the technical field of nitric acid evaporation, and in particular to a nitric acid evaporation device and process. Background Art

[0002] Nitric acid is a colorless, volatile strong acid with strong corrosiveness. As an important chemical raw material, nitric acid can be used in industry to make fertilizers, pesticides, explosives, dyes, etc. In organic chemistry, a mixture of concentrated nitric acid and concentrated sulfuric acid is an important nitrating reagent.

[0003] In the process of producing and purifying nitric acid, the temperature is usually increased or the pressure is reduced to evaporate the nitric acid, changing it from liquid to gas. The gaseous nitric acid is then condensed to obtain high-purity liquid nitric acid.

[0004] Referring to the Chinese patent document with announcement number CN220125515U and announcement date December 5, 2023, entitled A New Type of Nitric Acid Evaporation Device, the heat exchange contact area of ​​nitric acid is increased by opening diversion holes on the heating plate and the evaporation tube, thereby improving the evaporation efficiency of nitric acid. At the same time, the evaporation tube can be extended to the inside of the concentration chamber to improve the condensation effect of water vapor.

[0005] Referring to the above technical solution, since nitric acid is usually produced by decomposing sulfuric acid and oxidizing ammonia, in the synthesis process of nitric acid, it is inevitable that some substances will have incomplete reactions due to unsatisfactory reaction conditions. Eventually, these substances will remain in the nitric acid in the form of waste residues. In the subsequent evaporation process of nitric acid, the presence of these waste residues may cause the heating uniformity of nitric acid to be disturbed, thereby affecting the evaporation efficiency of nitric acid. Summary of the invention

[0006] In view of this, the present application provides a nitric acid evaporation device and process, which are mainly used to solve the problem that waste residue in nitric acid easily affects the evaporation effect.

[0007] In order to solve the above technical problems, the present application provides a nitric acid evaporation device and process.

[0008] In a first aspect, the present application provides a nitric acid evaporation device, comprising an evaporation tank, a condenser connected to a steam discharge hole at the top of a side wall of the evaporation tank, a drain pipe arranged at the bottom of the condenser, and a microwave heater arranged inside the evaporation tank; an upper rotor is provided through the top wall of the evaporation tank in a rotatable manner, a lower rotor is provided at the bottom of the upper rotor, and a slag discharge gap is reserved between the upper rotor and the lower rotor, a conical filter bucket matching the upper rotor and capable of blocking the slag discharge gap is vertically slidably connected inside the lower rotor, and a plurality of injection pipes are connected to the lower rotor; a slag collecting ring that can be sleeved on the top of the lower rotor and corresponds to the slag discharge gap is provided inside the evaporation tank, and the slag collecting ring is connected to a slag discharge pipe that can penetrate the evaporation tank and be connected to an external negative pressure air pump; a main hydraulic cylinder for driving the conical filter bucket to rise and fall and a driving assembly for driving the upper rotor and the lower rotor to rotate are provided on the evaporation tank.

[0009] By adopting the above technical solution, the waste residue mixed in the nitric acid is filtered out by utilizing the filtering effect of the conical filter bucket, thereby reducing the possibility that the subsequent nitric acid evaporation work will be interfered with by the waste residue.

[0010] Optionally, the driving assembly includes a driven gear arranged on the top of the upper rotor, a motor is arranged on the evaporator, and a driving gear meshing with the driven gear is arranged on the output shaft of the motor.

[0011] By adopting the above technical solution, the upper rotor can be driven to rotate.

[0012] Optionally, a plurality of slag pushing plates are provided at the bottom edge of the upper rotor, and the slag pushing plates are all located inside the slag collecting ring.

[0013] By adopting the above technical solution, the waste slag is pushed to a position facing the slag discharge pipe by using the slag pusher plate, which is beneficial to the slag discharge work.

[0014] Optionally, the injection pipes are all hinged on the lower rotor, and each injection pipe is connected to the inner cavity of the lower rotor through a flexible joint. The lower rotor is provided with a linkage member that can drive the injection pipe to swing when the conical filter bucket is raised or lowered.

[0015] Optionally, the linkage includes an auxiliary hydraulic cylinder arranged on the lower rotor, the input end of the auxiliary hydraulic cylinder is fixedly connected to the conical filter bucket, the output end of the auxiliary hydraulic cylinder is provided with a traction plate, each injection pipe is provided with a cam shaft, and the traction plate is provided with a plurality of waist holes corresponding to the cam shafts one by one.

[0016] By adopting the above technical solution, the direction of the spray pipe can be changed during the cleaning process, so that the clean water sprayed from the spray pipe can clean the inner cavity of the evaporator more comprehensively.

[0017] In a second aspect, the present application provides a nitric acid evaporation process, which is applied to a nitric acid evaporation device described in the first aspect, comprising the following steps:

[0018] S1, firstly, nitric acid is sent from the top of the upper rotor into the filtering chamber composed of the upper rotor, the lower rotor and the conical filter bucket;

[0019] S2, after being filtered by the conical filter, the nitric acid will enter the bottom of the inner cavity of the evaporator through the injection pipe, and the filtered waste residue will remain inside the conical filter and wait for subsequent removal;

[0020] S3, the microwave heater is operated to heat and evaporate the nitric acid at the bottom of the inner cavity of the evaporator. The evaporated gaseous nitric acid is condensed and liquefied by the condenser to be converted into high-purity liquid nitric acid, and finally the high-purity liquid nitric acid is discharged from the drain pipe.

[0021] By adopting the above technical solution, the waste residue in the nitric acid can be filtered out before the nitric acid evaporation work is carried out, so that the nitric acid evaporation work can be carried out normally.

[0022] Optionally, in S2, the upper rotor and the lower rotor are rotated by the cooperation of the driving assembly, and the conical filter bucket will also rotate accordingly. The waste residue filtered out by the conical filter bucket will gradually move up to the top edge of the conical filter bucket under the action of centrifugal force to prevent the filter holes on the conical filter bucket from being blocked by the waste residue.

[0023] By adopting the above technical solution and centrifugal filtration, the possibility of waste residues clogging the filter holes on the conical filter bucket can be reduced to a certain extent.

[0024] Optionally, in S2, the upper rotor and the lower rotor are rotated by the cooperation of the driving assembly, and when nitric acid enters the bottom of the inner cavity of the evaporator from the injection pipe, the injection pipe will deliver the nitric acid to the bottom of the inner cavity of the evaporator more evenly as the lower rotor rotates, and in the subsequent heating and evaporation process, the nitric acid continuously introduced by the injection pipe can be merged into the nitric acid in the evaporator in a jet stirring manner, so that the nitric acid is heated more evenly.

[0025] By adopting the above technical solution, the subsequent nitric acid is fed into the nitric acid in the evaporation tank in a jet stirring manner, so that the nitric acid can be heated evenly and the evaporation effect of the nitric acid is improved.

[0026] In summary, compared with the prior art, the present application includes at least one of the following beneficial technical effects:

[0027] 1. Before the nitric acid evaporation work is carried out, the waste residue in the nitric acid is removed by centrifugal filtration to reduce the possibility of interference of the nitric acid evaporation work by the waste residue, and the filtered waste residue can be kept away from the filter holes during the filtration process to prevent the filter holes from being blocked by the waste residue and affecting the effective implementation of the filtration work.

[0028] 2. During the evaporation of nitric acid, the nitric acid introduced subsequently can be introduced into the nitric acid in the evaporation tank in the form of jet stirring, so that the nitric acid is heated more evenly, which is conducive to the efficient evaporation of nitric acid.

[0029] 3. After the nitric acid is evaporated, the waste residue inside the conical filter bucket is automatically discharged by centrifugal throwing, thereby reducing the unloading difficulty and labor burden of the operator, and enabling the device to be quickly put into subsequent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of a nitric acid evaporation device for this application;

[0031] Figure 2 A cross-sectional view of the evaporation tank of this application;

[0032] Figure 3 This is a cross-sectional view of the upper rotor, lower rotor and slag collecting ring of the present application;

[0033] Figure 4 A cross-sectional view of the upper rotor and the lower rotor of the present application;

[0034] Figure 5 For this application Figure 3 A partial enlarged view of area A in the middle.

[0035] Explanation of the reference numerals in the accompanying drawings: 1. evaporator; 11. condenser; 12. drain pipe; 13. microwave heater; 2. upper rotor; 3. lower rotor; 31. injection pipe; 32. linkage; 321. auxiliary hydraulic cylinder; 322. traction plate; 323. cam; 4. slag discharge gap; 5. conical filter bucket; 6. slag collecting ring; 61. slag discharge pipe; 62. slag pushing plate; 7. main hydraulic cylinder; 8. drive assembly; 81. driven gear; 82. motor; 83. driving gear. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the embodiments of the present application. Figure 1-Figure 5 , the technical scheme of the embodiment of the present application is clearly and completely described. Obviously, the described embodiment is a part of the embodiment of the present application, not all of the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0037] In a first aspect, the present application provides a nitric acid evaporation device, which adopts the following technical solution:

[0038] Reference Figure 1 and Figure 2The present embodiment provides a nitric acid evaporation device, comprising an evaporation tank 1, a condenser 11, a drain pipe 12, a microwave heater 13 and a residue filter mechanism. The steam discharge hole opened on the top of the side wall of the evaporation tank 1 is connected to the condenser 11, the drain pipe 12 is arranged at the bottom of the condenser 11, and the microwave heater 13 is arranged at the bottom of the inner cavity of the evaporation tank 1.

[0039] Among them, refer to Figure 2 , Figure 3 and Figure 4 The slag filter mechanism includes an upper rotor 2, a lower rotor 3, a slag discharge gap 4, a conical filter bucket 5, an injection pipe 31, a drive assembly 8 and a slag discharge assembly. The upper rotor 2 is rotatably connected and penetrates the center of the top wall of the evaporator 1. The lower rotor 3 is arranged at the bottom of the upper rotor 2, and a slag discharge gap 4 is reserved between the upper rotor 2 and the lower rotor 3. The conical filter bucket 5 is vertically slidably connected inside the lower rotor 3 and matches the upper rotor 2. The conical filter bucket 5 can block the slag discharge gap 4. A plurality of injection pipes 31 are arranged and connected to the lower rotor 3 in an array arrangement. The drive assembly 8 is arranged in the evaporator 1 to drive the upper rotor 2 and the lower rotor 3 to rotate.

[0040] Among them, refer to Figure 2 The driving assembly 8 includes a driven gear 81, a motor 82 and a driving gear 83. The driven gear 81 is arranged on the top of the upper rotor 2, the motor 82 is arranged on the evaporator 1, and the output shaft of the motor 82 is provided with a driving gear 83 meshing with the driven gear 81. When the motor 82 is running and drives the driving gear 83 to rotate, the upper rotor 2 will rotate accordingly due to the meshing connection relationship between the driven gear 81 and the driving gear 83.

[0041] When nitric acid evaporation is carried out, the operator first feeds nitric acid into the filter chamber composed of the upper rotor 2, the lower rotor 3 and the conical filter bucket 5, and at the same time drives the upper rotor 2, the lower rotor 3 and the conical filter bucket 5 to rotate through the cooperation of the driving assembly 8. Under the filtering action of the conical filter bucket 5, the nitric acid will pass through the filter holes on the conical filter bucket 5 and enter the bottom of the inner cavity of the evaporation tank 1 through the injection pipe 31, while the filtered waste residue will remain inside the conical filter bucket 5. Due to the shape of the conical filter bucket 5, the waste residue will gradually move up to the top edge of the conical filter bucket 5 under the action of centrifugal force, reducing the possibility of the filter holes on the conical filter bucket 5 being blocked by the waste residue.

[0042] When the microwave heater 13 is running to heat and evaporate the nitric acid entering the bottom of the inner cavity of the evaporator 1, since the lower rotor 3 is continuously in a rotating state, the nitric acid continuously introduced by the injection pipe 31 can be merged into the nitric acid in the evaporator 1 in a jet stirring manner, thereby improving the heating uniformity of the nitric acid and facilitating the efficient evaporation of the nitric acid.

[0043] In addition, the input pipeline of nitric acid can be connected to the upper rotor 2 through a rotary joint. At the same time, the input pipeline of nitric acid can pass through the condenser 11, and the liquid nitric acid before evaporation is used as a condensing medium to exchange heat with the high-temperature gaseous nitric acid after evaporation passing through the condenser 11. The liquid nitric acid can be preheated before the evaporation work is carried out, which is beneficial to the subsequent evaporation work.

[0044] Among them, refer to Figure 2 , Figure 3 and Figure 4 The slag discharge assembly includes a slag collecting ring 6, a slag discharge pipe 61 and a main hydraulic cylinder 7. The slag collecting ring 6 is arranged inside the evaporation tank 1, and the slag collecting ring 6 is sleeved on the top of the lower rotor 3 and corresponds to the slag discharge gap 4. The slag discharge pipe 61 penetrates the outer wall of the evaporation tank 1 and is connected between the slag collecting ring 6 and the external negative pressure air pump. The main hydraulic cylinder 7 is arranged on the evaporation tank 1, and the main hydraulic cylinder 7 is used to drive the conical filter bucket 5 to rise and fall.

[0045] After the nitric acid has evaporated and is discharged through the drain pipe 12, the main hydraulic cylinder 7 drives the conical filter bucket 5 to move downward, releasing the blocking state of the conical filter bucket 5 on the slag discharge gap 4. At this time, the upper rotor 2, the lower rotor 3 and the conical filter bucket 5 are still in a rotating state, so that the waste slag is thrown into the interior of the slag collecting ring 6, and then the waste slag is discharged from the slag discharge pipe 61 with the cooperation of the external negative pressure air pump.

[0046] Reference Figure 3 and Figure 4 A plurality of slag pushing plates 62 are arranged at the bottom edge of the upper rotor 2 , and the slag pushing plates 62 are all located inside the slag collecting ring 6 .

[0047] When the waste slag is thrown into the slag collecting ring 6, the multiple slag pushing plates 62 located at the bottom edge of the upper rotor 2 can push the waste slag as the upper rotor 2 rotates, causing the waste slag to change position inside the slag collecting ring 6 until the waste slag is pushed to a position opposite to the slag discharge pipe 61 and discharged under the action of an external negative pressure air pump, which is beneficial to the slag discharge work.

[0048] Reference Figure 3 , Figure 4 and Figure 5 The injection pipes 31 are hinged on the lower rotor 3, and each injection pipe 31 is connected to the inner cavity of the lower rotor 3 through a flexible joint. The lower rotor 3 is provided with a linkage 32 that can drive the injection pipe 31 to swing when the conical filter bucket 5 is raised or lowered. The linkage 32 includes a secondary hydraulic cylinder 321, a traction plate 322 and a convex shaft 323. The secondary hydraulic cylinder 321 is provided on the lower rotor 3, and the input end of the secondary hydraulic cylinder 321 is fixedly connected to the conical filter bucket 5. The output end of the secondary hydraulic cylinder 321 is provided with a traction plate 322. Each injection pipe 31 is provided with a convex shaft 323, and the traction plate 322 is provided with a plurality of waist holes corresponding to the convex shaft 323.

[0049] After the waste residue is discharged, the operator can send external clean water into the evaporation tank 1 through the upper rotor 2 for cleaning. During this process, the main hydraulic cylinder 7 can periodically drive the conical filter bucket 5 to rise and fall, and then through the cooperation of the auxiliary hydraulic cylinder 321, the traction plate 322 can change its position and apply a certain pressure to the convex shaft 323, thereby changing the direction of the injection pipe 31, so that the clean water sprayed by the injection pipe 31 can clean the inner cavity of the evaporation tank 1 more comprehensively.

[0050] The implementation principle of a nitric acid evaporation device in the embodiment of the present application is:

[0051] When carrying out nitric acid evaporation work, the operator first sends nitric acid into the filter chamber composed of the upper rotor 2, the lower rotor 3 and the conical filter bucket 5, and at the same time drives the upper rotor 2, the lower rotor 3 and the conical filter bucket 5 to rotate through the cooperation of the driving component 8.

[0052] Under the filtering action of the conical filter 5, nitric acid will pass through the filter holes on the conical filter 5 and enter the bottom of the inner cavity of the evaporator 1 through the injection pipe 31, while the filtered waste residue will remain inside the conical filter 5. Due to the shape of the conical filter 5, the waste residue will gradually move up to the top edge of the conical filter 5 under the action of centrifugal force, reducing the possibility of the filter holes on the conical filter 5 being blocked by the waste residue.

[0053] When the microwave heater 13 is running to heat and evaporate the nitric acid entering the bottom of the inner cavity of the evaporator 1, since the lower rotor 3 is continuously in a rotating state, the nitric acid continuously introduced by the injection pipe 31 can be merged into the nitric acid in the evaporator 1 in a jet stirring manner, thereby improving the heating uniformity of the nitric acid and facilitating the efficient evaporation of the nitric acid.

[0054] After the nitric acid has evaporated and is discharged through the drain pipe 12, the main hydraulic cylinder 7 drives the conical filter bucket 5 to move downward, releasing the blocking state of the conical filter bucket 5 on the slag discharge gap 4. At this time, the upper rotor 2, the lower rotor 3 and the conical filter bucket 5 are still in a rotating state, so that the waste slag is thrown into the interior of the slag collecting ring 6, and then the waste slag is discharged from the slag discharge pipe 61 with the cooperation of the external negative pressure air pump.

[0055] In a second aspect, the present application provides a nitric acid evaporation process, which is applied to a nitric acid evaporation device in the first aspect, comprising the following steps:

[0056] S1, firstly, nitric acid is sent from the top of the upper rotor 2 into the filtering chamber composed of the upper rotor 2, the lower rotor 3 and the conical filter hopper 5;

[0057] S2, after being filtered by the conical filter 5, the nitric acid will enter the bottom of the inner cavity of the evaporation tank 1 through the injection pipe 31, and the filtered waste residue will remain inside the conical filter 5 and wait for subsequent removal;

[0058] S3, the microwave heater 13 is operated to heat and evaporate the nitric acid at the bottom of the inner cavity of the evaporation tank 1. The evaporated gaseous nitric acid is condensed and liquefied by the condenser 11 to be converted into high-purity liquid nitric acid, and finally the high-purity liquid nitric acid is discharged from the drain pipe 12.

[0059] In S2, the upper rotor 2 and the lower rotor 3 are rotated by the cooperation of the driving assembly 8, and the conical filter bucket 5 will also rotate accordingly. The waste residue filtered out by the conical filter bucket 5 will gradually move up to the top edge of the conical filter bucket 5 under the action of centrifugal force to prevent the filter holes on the conical filter bucket 5 from being blocked by the waste residue.

[0060] In S2, the upper rotor 2 and the lower rotor 3 are rotated by the cooperation of the driving assembly 8. When the nitric acid enters the bottom of the inner cavity of the evaporation tank 1 through the injection pipe 31, the injection pipe 31 will deliver the nitric acid to the bottom of the inner cavity of the evaporation tank 1 more evenly as the lower rotor 3 rotates. In the subsequent heating and evaporation process, the nitric acid continuously introduced by the injection pipe 31 can be merged into the nitric acid in the evaporation tank 1 in a jet stirring manner, so that the nitric acid is heated more evenly.

[0061] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0062] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles described in the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A nitric acid evaporation device, comprising an evaporation tank (1), a condenser (11) connected to a steam discharge hole at the top of a side wall of the evaporation tank (1), a liquid discharge pipe (12) arranged at the bottom of the condenser (11), and a microwave heater (13) arranged inside the evaporation tank (1), characterized in that: The top wall of the evaporator (1) is provided with an upper rotor (2) penetrating therethrough in a rotatable manner, a lower rotor (3) is provided at the bottom of the upper rotor (2), a slag discharge gap (4) is reserved between the upper rotor (2) and the lower rotor (3), a conical filter bucket (5) matching the upper rotor (2) and capable of blocking the slag discharge gap (4) is vertically slidably connected inside the lower rotor (3), a plurality of injection pipes (31) are connected to the lower rotor (3), the injection pipes (31) are hinged to the lower rotor (3), and each injection pipe (31) is connected to the inner cavity of the lower rotor (3) via a flexible joint, and a linkage member (32) is provided on the lower rotor (3) and capable of driving the injection pipe (31) to swing when the conical filter bucket (5) is raised or lowered; The evaporator (1) is provided with a slag collecting ring (6) which can be sleeved on the top of the lower rotor (3) and corresponds to the slag discharging gap (4), and the slag collecting ring (6) is connected to a slag discharging pipe (61) which can penetrate the evaporator (1) and is connected to an external negative pressure air pump; the evaporator (1) is provided with a main hydraulic cylinder (7) for driving the conical filter bucket (5) to rise and fall, and a driving assembly (8) for driving the upper rotor (2) and the lower rotor (3) to rotate; after being filtered by the conical filter bucket (5), the nitric acid enters the bottom of the inner cavity of the evaporator (1) through the injection pipe (31).

2. A nitric acid evaporation device according to claim 1, characterized in that: The driving assembly (8) comprises a driven gear (81) arranged on the top of the upper rotor (2); a motor (82) is arranged on the evaporator (1); and a driving gear (83) meshing with the driven gear (81) is arranged on the output shaft of the motor (82).

3. A nitric acid evaporation device according to claim 1, characterized in that: A plurality of slag pushing plates (62) are arranged at the bottom edge of the upper rotor (2), and the slag pushing plates (62) are all located inside the slag collecting ring (6).

4. A nitric acid evaporation device according to claim 1, characterized in that: The linkage member (32) comprises an auxiliary hydraulic cylinder (321) arranged on the lower rotor (3); the input end of the auxiliary hydraulic cylinder (321) is fixedly connected to the conical filter bucket (5); the output end of the auxiliary hydraulic cylinder (321) is provided with a traction plate (322); each injection pipe (31) is provided with a convex shaft (323); and the traction plate (322) is provided with a plurality of waist holes corresponding to the convex shafts (323) one by one.

5. A nitric acid evaporation process, applied to a nitric acid evaporation device according to claim 1, characterized in that: The following steps are involved: S1, firstly, nitric acid is sent from the top of the upper rotor (2) into a filtering chamber composed of the upper rotor (2), the lower rotor (3) and the conical filter bucket (5); S2, after being filtered by the conical filter (5), the nitric acid will enter the bottom of the inner cavity of the evaporation tank (1) through the injection pipe (31), and the filtered waste residue will remain inside the conical filter (5) and wait for subsequent removal; S3, the microwave heater (13) is operated to heat and evaporate the nitric acid at the bottom of the inner cavity of the evaporation tank (1), and the evaporated gaseous nitric acid is converted into high-purity liquid nitric acid after condensation and liquefaction by the condenser (11), and finally the high-purity liquid nitric acid is discharged through the drain pipe (12).

6. A nitric acid evaporation process according to claim 5, characterized in that: In S2, the upper rotor (2) and the lower rotor (3) are rotated by the cooperation of the driving assembly (8), and the conical filter bucket (5) also rotates accordingly. The waste residue filtered out by the conical filter bucket (5) gradually moves upward to the top edge of the conical filter bucket (5) under the action of centrifugal force, so as to prevent the filter holes on the conical filter bucket (5) from being blocked by the waste residue.

7. A nitric acid evaporation process according to claim 5, characterized in that: In S2, the upper rotor (2) and the lower rotor (3) are rotated by the cooperation of the driving assembly (8). When nitric acid enters the bottom of the inner cavity of the evaporation tank (1) through the injection pipe (31), the injection pipe (31) will deliver the nitric acid to the bottom of the inner cavity of the evaporation tank (1) more evenly as the lower rotor (3) rotates. In the subsequent heating and evaporation process, the nitric acid continuously introduced by the injection pipe (31) can be merged into the nitric acid in the evaporation tank (1) in a jet stirring manner, so that the nitric acid is heated more evenly.

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