A sulfuric acid defluorination system and defluorination process

Abstract

This invention belongs to the field of sulfuric acid defluorination technology, and particularly relates to a sulfuric acid defluorination system and a defluorination process for the system. The defluorination tank has an inlet and an outlet. An inner tank is formed within the internal gap of the defluorination tank, creating a collection space A between the defluorination tank and the inner tank. A silicon column is placed within the internal gap of the inner tank, forming a primary defluorination space B between the inner tank and the silicon column. The inlet is located above the primary defluorination space B. The silicon column has a longitudinally arranged through hole, forming a secondary defluorination space C. In this sulfuric acid defluorination system, the silicon column is combined with negative pressure, allowing for two defluorination operations under negative pressure. The defluorination operation is continuous, improving the defluorination effect. Furthermore, by setting up a collection pipe, and having sulfuric acid enter the collection space A from the secondary defluorination space C through the collection pipe, the negative pressure value in the system can be kept stable, avoiding fluctuations in the negative pressure value from affecting the defluorination effect.

Description

Technical Field

[0001] This invention belongs to the field of sulfuric acid defluorination technology, and particularly relates to a sulfuric acid defluorination system and the defluorination process of the defluorination system. Background Technology

[0002] Fluoride ions in sulfuric acid solutions are toxic and can directly harm living organisms; at the same time, fluoride ions are also corrosive.

[0003] When the fluoride ion concentration in sulfuric acid is 2000 ppm or higher, it is highly corrosive to steel. It can only be transported and stored using PTFE-lined steel pipes, which limits its downstream use. Defluorinating sulfuric acid to reduce the fluoride ion concentration can greatly reduce the corrosion of equipment. When transporting sulfuric acid, steel pipes can be used, with minimal impact on downstream equipment.

[0004] To address the issue of sulfuric acid defluorination, a sulfuric acid defluorination system and its defluorination process are designed. Summary of the Invention

[0005] To address the problems in the prior art, the present invention proposes the following technical solution:

[0006] A sulfuric acid defluorination system includes a defluorination tank with an inlet and an outlet. An inner tank is provided within the internal gap of the defluorination tank, forming a collection space A between the defluorination tank and the inner tank. A silicon column is provided within the internal gap of the inner tank, forming a primary defluorination space B between the inner tank and the silicon column. The inlet is located above the primary defluorination space B. The silicon column has a longitudinally arranged through hole, forming a secondary defluorination space C.

[0007] The upper end of the silicon pillar is provided with a cylinder that is under negative pressure. At least one collecting pipe is connected through the side wall of the cylinder, and the movable end of the collecting pipe extends to the top of the collecting space A.

[0008] Sulfuric acid to be defluorinated enters the primary defluorination space B and the secondary defluorination space C through the feed inlet of the defluorination tank. Under negative pressure, the primary and secondary defluorination operations are carried out. Under the action of negative pressure, the sulfuric acid enters the collection space A through the collection pipe from the secondary defluorination space C and is then discharged from the discharge outlet of the defluorination tank.

[0009] As a preferred embodiment of the above technical solution, the collecting pipe and the cylinder are movably assembled, and the cylinder has a longitudinally formed strip hole.

[0010] The collecting pipe is fitted with the same sleeve, which is fitted outside the cylinder body, and a bolt is threaded into the threaded hole on the sleeve.

[0011] One end of the collecting pipe extends into the interior of the strip hole and slides therewith.

[0012] As a preferred embodiment of the above technical solution, it also includes a mixing tank and a storage tank. The mixing tank has an inlet and an outlet. The outlet of the mixing tank is connected to the inlet of the defluorination tank through a pipe body. A pump is installed on the pipe body.

[0013] The storage tank has an inlet and an outlet. The outlet of the defluorination tank is connected to the inlet of the storage tank via a second pipe, and a second pump is installed on the second pipe.

[0014] As a preferred embodiment of the above technical solution, a heating component 1 is provided at the end of the tube body that connects to the defluorination tank, and a heating component 2 is embedded in the side wall of the inner tank body.

[0015] As a preferred embodiment of the above technical solution, a support body is provided inside the outer tank, and the inner tank is assembled at the upper end of the support body. The support body is provided with a hole for sulfuric acid to flow through.

[0016] As a preferred embodiment of the above technical solution, a second support body is provided inside the inner tank, and the silicon pillar is assembled at the upper end of the second support body.

[0017] The second support includes a base with a central hole. The central hole is coaxially arranged with the through hole of the silicon pillar. A rod is installed between the base and the inner wall of the inner tank.

[0018] As a preferred embodiment of the above technical solution, the lower end of the cylinder is provided with a groove, the upper end of the support body is provided with a groove, and the upper and lower ends of the silicon pillar are respectively assembled in the groove and the groove.

[0019] As a preferred embodiment of the above technical solution, the outer tank includes a base tank and an upper cover assembled with the base tank;

[0020] The first tube is mounted on the top cover, and the second tube is mounted on the base tank.

[0021] As a preferred embodiment of the above technical solution, a negative pressure pipe is provided at the upper end of the cylinder, and the movable end of the negative pressure pipe penetrates the outer tank and is equipped with a fan.

[0022] An air supply pipe is installed through the outer tank.

[0023] A defluorination process for a sulfuric acid defluorination system includes the following steps:

[0024] S1. Acid injection: The sulfuric acid to be defluorinated is continuously injected into the primary defluorination space B through the feed port of the outer tank, and then enters the secondary defluorination space C through the gap between the lower end of the silicon column and the inner tank.

[0025] S2, Defluorination: Sulfuric acid enters the primary defluorination space B and comes into contact with the outer surface of the silicon column under negative pressure to perform the primary defluorination operation; it then enters the secondary defluorination space C and comes into contact with the inner surface of the silicon column under negative pressure to perform the secondary defluorination operation.

[0026] S3, Acid Discharge: Under negative pressure, the defluorinated sulfuric acid enters the collection space A through the collecting pipe and is discharged from the outlet of the outer tank.

[0027] The beneficial effects of this invention are as follows:

[0028] In this sulfuric acid defluorination system, the sulfuric acid to be defluorinated enters the primary defluorination space B and the secondary defluorination space C through the feed inlet of the defluorination tank. Under negative pressure, the primary defluorination operation and the secondary defluorination operation are carried out. Under the action of negative pressure, the sulfuric acid enters the collection space A through the collection pipe from the secondary defluorination space C and is then discharged from the discharge outlet of the defluorination tank.

[0029] By combining silicon columns with negative pressure, two defluorination operations are performed under negative pressure, and the defluorination operation is continuous, which improves the defluorination effect. In particular, by setting up a collection pipe, and by having sulfuric acid enter the collection space A from the secondary defluorination space C through the collection pipe, the negative pressure value of the system can be kept stable, and the defluorination effect can be avoided due to fluctuations in the negative pressure value. Attached Figure Description

[0030] Figure 1 The diagram shown is a structural schematic of a sulfuric acid defluorination system in Example 1;

[0031] Figure 2 What is shown is Figure 1 Schematic diagram of the internal structure of the defluorination tank;

[0032] Figure 3 What is shown is Figure 2 Top view of the structure of the second central support;

[0033] Figure 4 The diagram shown is an assembly diagram of the cylinder and the collecting pipe in Example 2.

[0034] Reference numerals: 10 for mixing tank, 20 for defluorination tank, 21 for outer tank, A for collection space, 22 for inner tank, B for primary defluorination space, 23 for silicon column, C for secondary defluorination space, 24 for cylinder, 241 for strip hole, 242 for tank body one, 25 for collecting pipe, 251 for sleeve, 252 for bolt, 26 for negative pressure pipe, 261 for fan, 27 for support body one, 271 for hole body, 28 for support body two, 281 for base, 282 for central hole, 283 for tank body two, 284 for rod body, 30 for storage tank, 40 for pipe body one, 41 for pump body one, 50 for pipe body two, 51 for pump two. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0036] Example 1

[0037] like Figure 2 As shown, a sulfuric acid defluorination system includes a defluorination tank 20, which has an inlet and an outlet. An inner tank 22 is provided in the internal gap of the defluorination tank 20, and a collection space A is formed between the defluorination tank 20 and the inner tank 22. A silicon column 23 is provided in the internal gap of the inner tank 22, and a primary defluorination space B is formed between the inner tank 22 and the silicon column 23. The inlet is located above the primary defluorination space B. The silicon column 23 has a longitudinally arranged through hole, which forms a secondary defluorination space C.

[0038] The upper end of the silicon pillar 23 is provided with a cylinder 24 that is under negative pressure. At least one collecting pipe 25 is connected through the side wall of the cylinder 24. The movable end of the collecting pipe 25 extends to the top of the collecting space A. The collecting pipe 25 and a feed port are staggered in the projection direction to avoid impact and collision between sulfuric acid and the collecting pipe 25 when the sulfuric acid is injected into the primary defluorination space B.

[0039] In this sulfuric acid defluorination system, the sulfuric acid to be defluorinated enters the primary defluorination space B and the secondary defluorination space C through the inlet of the defluorination tank 20. Under negative pressure, the primary defluorination operation and the secondary defluorination operation are carried out. The silicon dioxide in the silicon column 23 reacts with the hydrogen fluoride in the sulfuric acid to produce silicon tetrafluoride gas. Under the action of negative pressure, the sulfuric acid enters the collection space A through the collection pipe 25 from the secondary defluorination space C and is then collected, and finally discharged from the outlet of the defluorination tank 20.

[0040] By combining the silicon column 23 with negative pressure, two defluorination operations are performed under negative pressure, and the defluorination operation is continuous, which improves the defluorination effect. In particular, by setting up the collection pipe 25, and the sulfuric acid enters the collection space A from the secondary defluorination space C through the collection pipe 25, the negative pressure value of the system can be kept stable, and the defluorination effect is avoided due to the fluctuation of the negative pressure value.

[0041] like Figure 1 As shown, in order to enable the defluorination system to perform continuous defluorination operation, the sulfuric acid defluorination system also includes a mixing tank 10 and a storage tank 30. The mixing tank 10 is used for mixing sulfuric acid and temporarily storing sulfuric acid to be defluorinated. The mixing tank 10 has an inlet and an outlet. The outlet of the mixing tank 10 is connected to the inlet of the defluorination tank 20 through a pipe body 40. A pump 41 is installed on the pipe body 40.

[0042] Storage tank 30 stores sulfuric acid after defluorination. Storage tank 30 has an inlet and an outlet. The outlet of defluorination tank 20 and the inlet of storage tank 30 are connected by a pipe body 2 50. A pump 2 51 is installed on the pipe body 2 50.

[0043] In this sulfuric acid defluorination system, under the lifting action of pump 41, the sulfuric acid stored in the mixing tank 10 is injected into the defluorination tank 20, and under the lifting action of pump 51, the sulfuric acid after defluorination is injected into the storage tank 30.

[0044] like Figure 1 , Figure 2 As shown, in order to improve the defluorination effect of this sulfuric acid defluorination system, a heating component 1 is provided at the end of the pipe body 40 connected to the defluorination tank 20 to preheat the sulfuric acid that is about to enter the defluorination tank 20. A heating component 2 is embedded in the side wall of the inner tank 22 to heat and keep the sulfuric acid that enters the defluorination tank 20. The temperature of the heating component 1 is set to 90°C and the temperature of the heating component 2 is set to 100°C.

[0045] like Figure 2 As shown, in order to meet the gap setting between the outer tank 21 and the inner tank 22, a support body 27 is provided inside the outer tank 21, and the inner tank 22 is assembled on the upper end of the support body 27, so that there are gaps between the side walls and bottom walls of the outer tank 21 and the inner tank 22. The support body 27 is provided with a hole 271 for sulfuric acid to flow through. Sulfuric acid enters through the upper end of the collection space A and is discharged through the outlet between the bottom walls of the outer tank 21 and the inner tank 22.

[0046] like Figure 2 As shown, in order to meet the gap setting between the inner tank 22 and the silicon pillar 23, a second support body 28 is provided inside the inner tank 22, and the silicon pillar 23 is assembled on the upper end of the second support body 28.

[0047] The second support body 28 includes a base 281 with a central hole 282. The central hole 282 is coaxially arranged with the through hole of the silicon pillar 23. A rod 284 is installed between the base 281 and the inner wall of the inner tank 22. Sulfuric acid enters the interior of the secondary defluorination space C through the primary defluorination space B, between the adjacent rods 284, and through the central hole 282.

[0048] like Figure 3 , Figure 4As shown, during the defluorination operation of silicon column 23, silicon dioxide reacts with hydrogen fluoride in sulfuric acid to produce silicon tetrafluoride gas. After a period of reaction, the defluorination effect is not as obvious as during the initial defluorination, and the volume of silicon column 23 will shrink. Therefore, it is necessary to replace silicon column 23. Silicon column 23 is movably installed inside inner tank 22. Specifically, the lower end of cylinder 24 has a groove 242, and the upper end of support 28 has a groove 283. The upper and lower ends of silicon column 23 are respectively assembled in groove 242 and groove 283. Cylinder 24 and support 28 clamp and fix silicon column 23 inside inner tank 22.

[0049] Furthermore, such as Figure 2 As shown, to facilitate the removal of the silicon pillar 23 from the inside of the outer tank 21, the outer tank 21 includes a base tank and an upper cover assembled with the base tank; tube 1 40 is disposed on the upper cover, and tube 2 50 is disposed on the base tank.

[0050] like Figure 2 As shown, the inside of the cylinder 24 is under negative pressure. A negative pressure pipe 26 is provided at the upper end of the cylinder 24. The movable end of the negative pressure pipe 26 passes through the outer tank 21 and is equipped with a fan 261.

[0051] To ensure continuous gas discharge and keep the system in a continuous defluorination state, a makeup air pipe is installed through the outer tank 21, and a makeup air valve is installed on the makeup air pipe.

[0052] A defluorination process for a sulfuric acid defluorination system includes the following steps:

[0053] S1. Acid injection: The sulfuric acid to be defluorinated is continuously injected into the primary defluorination space B through the feed port of the outer tank 21, and enters the secondary defluorination space C through the gap between the lower end of the silicon column 23 and the inner tank 22. To ensure the defluorination effect, the sulfuric acid flow rate can be set at about 100 kg / h.

[0054] S2. Defluorination: Sulfuric acid enters the primary defluorination space B and comes into contact with the outer surface of the silicon column 23 under negative pressure to perform the primary defluorination operation; it then enters the secondary defluorination space C and comes into contact with the inner surface of the silicon column 23 under negative pressure to perform the secondary defluorination operation.

[0055] S3, Acid Discharge: Under negative pressure, the defluorinated sulfuric acid enters the collection space A through the collection pipe 25 and is discharged from the outlet of the outer tank 21.

[0056] This sulfuric acid defluorination system employs a defluorination process where the sulfuric acid to be defluorinated is introduced into a primary defluorination space B, a secondary defluorination space C, and then a collection space A under negative pressure. Under negative pressure, the sulfuric acid in the primary defluorination space B contacts the outer surface of the silicon column 23 for primary defluorination, and in the secondary defluorination space C, it contacts the inner surface of the silicon column 23 for secondary defluorination. This sulfuric acid defluorination system combines the silicon column 23 with negative pressure, maintaining the defluorination process under negative pressure for continuous defluorination, resulting in excellent defluorination performance.

[0057] Example 2

[0058] Derived from Example 1, the difference from Example 1 is that, as Figure 4 As shown, the collecting pipe 25 and the cylinder 24 are movably assembled. A longitudinally spaced slotted hole 241 is provided on the cylinder 24. The collecting pipe 25 is fitted with the same sleeve 251, which is fitted onto the outside of the cylinder 24. A bolt 252 is threaded into a threaded hole on the sleeve 251. The collecting pipe 25 is adjusted to a suitable position in the height direction of the cylinder 24, and the bolt 252 is rotated until it abuts against the outer wall of the cylinder 24, thus fixing the relative position of the collecting pipe 25 and the cylinder 24.

[0059] Because the initial fluoride ion content in the sulfuric acid to be defluorinated varies, and because the defluorination process is not solely focused on achieving a high defluorination rate—for example, a sulfuric acid concentration of 90.33% with a fluoride ion content of 433 ppm will severely corrode carbon steel but will have virtually no corrosion to 304 stainless steel, PP, and PE—while a relative ion content of 733 ppm will cause relatively less corrosion to carbon steel—it is necessary to determine the defluorination effect based on the initial fluoride ion content in the sulfuric acid, the conveying equipment, and other conditions. Furthermore, the negative pressure value, i.e., the height position of the collection pipe at 25°, needs to be adjusted based on the defluorination effect.

[0060] The movable assembly of the collecting pipe 25 and the cylinder 24, which allows for longitudinal movement, enables the height of the collecting pipe 25 to be adjusted according to the negative pressure value required during the defluorination process, thereby meeting the defluorination requirements. The higher the height of the collecting pipe 25, the greater the corresponding negative pressure value; the lower the height of the collecting pipe 25, the smaller the corresponding negative pressure value.

[0061] like Figure 4 As shown, in order to avoid the material collection pipe 25 changing in the circumferential direction when the vertical position of the material collection pipe 25 is changed, and the material collection pipe 25 and the feed inlet coinciding in the projection direction, which would affect the injection effect, a limit mechanism is provided on the material collection pipe 25. Specifically, one end of the material collection pipe 25 extends into the interior of the strip hole 241 and slides therewith.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A sulfuric acid defluorination system comprising a defluorination tank (20) having an inlet, an outlet and an outer tank body (21), characterized in that, The internal gap of the defluorination tank (20) is provided with an inner tank body (22), and a collection space A is formed between the outer tank body (21) and the inner tank body (22). A silicon column (23) is provided in the internal gap of the inner tank body (22), and a primary defluorination space B is formed between the inner tank body (22) and the silicon column (23). The feed inlet is located above the primary defluorination space B. The silicon column (23) has a longitudinally arranged through hole, and the through hole forms a secondary defluorination space C. The upper end of the silicon pillar (23) is provided with a cylinder (24) under negative pressure. At least one collecting pipe (25) is connected through the side wall of the cylinder (24). The movable end of the collecting pipe (25) extends to the top of the collecting space A. The inner tank (22) is provided with a support body two (28), and the silicon pillar (23) is assembled at the upper end of the support body two (28); The second support body (28) includes a base (281), on which a central hole (282) is provided. The central hole (282) is coaxially arranged with the through hole of the silicon pillar (23). A rod (284) is installed between the base (281) and the inner wall of the inner tank (22). The lower end of the cylindrical body (24) is provided with a groove (242), and the upper end of the support body (28) is provided with a groove (283). The upper and lower ends of the silicon pillar (23) are respectively assembled in the groove (242) and the groove (283). A negative pressure pipe (26) is provided at the upper end of the cylindrical body (24), and the movable end of the negative pressure pipe (26) passes through the outer tank (21) and is provided with a fan (261). The sulfuric acid to be defluorinated enters the primary defluorination space B through the inlet of the defluorination tank (20). Under negative pressure, it comes into contact with the outer surface of the silicon column (23) to perform primary defluorination, causing the silicon dioxide in the silicon column (23) to react with the hydrogen fluoride in the sulfuric acid to produce silicon tetrafluoride gas. Subsequently, the sulfuric acid enters the secondary defluorination space C through the gap and the central hole between the lower end of the silicon column (23) and the inner tank (22). Under negative pressure, the sulfuric acid comes into contact with the inner surface of the silicon column (23) to perform secondary defluorination, causing the silicon dioxide in the silicon column (23) to react with the hydrogen fluoride in the sulfuric acid to produce silicon tetrafluoride gas. Under negative pressure, the sulfuric acid enters the collection space A through the collection pipe (25) from the secondary defluorination space C and is then discharged from the outlet of the defluorination tank (20).

2. The sulfuric acid defluorination system according to claim 1, characterized in that, The collecting pipe (25) and the cylinder (24) are movably assembled, and the cylinder (24) has a longitudinally formed strip hole (241). The collecting pipe (25) is fitted with the same sleeve (251), which is fitted on the outside of the cylinder (24). A bolt (252) is threaded into the threaded hole on the sleeve (251). One end of the collecting pipe (25) extends into the interior of the strip hole (241) and slides therewith.

3. The sulfuric acid defluorination system according to claim 1, characterized in that, It also includes a mixing tank (10) and a storage tank (30). The mixing tank (10) has an inlet and an outlet. The outlet of the mixing tank (10) is connected to the inlet of the defluorination tank (20) through a pipe body (40). A pump (41) is installed on the pipe body (40). The storage tank (30) has an inlet and an outlet. The outlet of the defluorination tank (20) is connected to the inlet of the storage tank (30) through a pipe body two (50). A pump two (51) is installed on the pipe body two (50).

4. The sulfuric acid defluorination system according to claim 3, characterized in that, Heating component one is provided at the end of the tube body one (40) connected to the defluorination tank (20), and heating component two is embedded in the side wall of the inner tank body (22).

5. The sulfuric acid defluorination system according to claim 1, characterized in that, The outer tank (21) is provided with a support body (27) inside, and the inner tank (22) is assembled at the upper end of the support body (27). The support body (27) is provided with a hole (271) for sulfuric acid to flow through.

6. The sulfuric acid defluorination system according to claim 3, characterized in that, The outer tank (21) includes a base tank and an upper cover assembled with the base tank; The first tube (40) is mounted on the top cover, and the second tube (50) is mounted on the base tank.

7. The sulfuric acid defluorination system according to claim 1, characterized in that, An air supply pipe is provided through the outer tank (21).

8. The defluorination process of a sulfuric acid defluorination system according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Acid injection: The sulfuric acid to be defluorinated is continuously injected into the primary defluorination space B through the feed port of the defluorination tank (20). Then, the sulfuric acid enters the secondary defluorination space C through the gap and the central hole between the lower end of the silicon column (23) and the inner tank (22). S2, Defluorination: Sulfuric acid enters the primary defluorination space B and comes into contact with the outer surface of the silicon column (23) under negative pressure to perform primary defluorination operation; Sulfuric acid enters the secondary defluorination space C and comes into contact with the inner surface of the silicon column (23) under negative pressure to perform secondary defluorination operation. S3, Acid discharge: Under negative pressure, the defluorinated sulfuric acid enters the collection space A through the collection pipe (25), and is discharged from the outlet of the defluorination tank (20) after collection.

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