A device for desulfurization and purification of expanded graphite

Abstract

This invention provides a desulfurization and purification device for expanded graphite, comprising a closed box body. The interior of the box body is divided into a stirring chamber, a cleaning chamber, and a purging chamber, which are connected sequentially from top to bottom. The cleaning chamber includes at least two interconnected cleaning spaces, with a high-pressure water pump installed at the connection between the cleaning spaces. The purging chamber includes a receiving tank with a filter plate at its bottom, and a suction pipe at the bottom of the filter plate. In this invention, the added expanded graphite and desulfurizing agent are first mixed evenly in the stirring chamber by a stirrer, and then enter the cleaning chamber. This allows the desulfurizing agent to enter the pores of the expanded graphite and fully react with the residual sulfur dioxide, dissolving the sulfur dioxide into a solution and separating it from the expanded graphite. Finally, solid-liquid separation is achieved through the purging chamber, thus realizing the desulfurization of the expanded graphite. This method allows the desulfurizing agent to react more effectively with the sulfur dioxide in the pores of the expanded graphite, thereby further improving the desulfurization effect.

Description

Technical Field

[0001] This invention relates to the field of expanded graphite processing technology, and in particular to an expanded graphite desulfurization and purification device. Background Technology

[0002] Graphite is a crystalline carbon material with a unique structure. Expanded graphite, made from natural graphite, has a porous structure and is an excellent adsorbent material. Furthermore, due to its high temperature resistance, corrosion resistance, and radiation resistance, it can be used as a sealing material in industries such as chemical, environmental protection, metallurgy, and nuclear power. In addition, expanded graphite can be further processed into graphene, which has even better performance.

[0003] In the process of preparing expanded graphite from natural graphite, concentrated sulfuric acid is used to react with natural flake graphite in the presence of an oxidizing agent to undergo an intercalation reaction. This traditional method produces expandable graphite with a sulfur content as high as 3%-4.5%, primarily in the form of SO4. 2- Sulfur exists in the form of graphite. Electrochemical and crevice corrosion tests show that the sulfur content in graphite sealing materials has a significant impact on the electrochemical corrosion rate of the mating metal in contact with it; as the sulfur content increases, the electrochemical corrosion rate also increases accordingly. Therefore, controlling the sulfur content of graphite materials during processing and preparing low-sulfur or even sulfur-free graphite materials is of great significance.

[0004] Current expanded graphite desulfurization technologies mainly include the following:

[0005] Sulfur-free substitution method: This method uses systems such as nitric acid and phosphoric acid, or nitric acid and hydrogen peroxide, instead of concentrated sulfuric acid as intercalating agents. This way, the raw materials do not contain sulfur, and after the graphite expands during the intercalation reaction, it naturally does not contain sulfur internally. However, this method has two drawbacks: higher cost and the introduction of new impurities, which still affects the expanded graphite during use.

[0006] High-temperature expansion method: Using laser, microwave heating, or other methods in conjunction with heating during the expansion stage can not only further enhance the expansion effect but also completely decompose sulfate ions at high temperatures, resulting in the rapid generation and discharge of large amounts of sulfur dioxide. However, this method essentially only accelerates the expansion process of the intercalation reaction, causing more of the generated sulfur dioxide to be ejected outwards, but some will still remain in the voids of the expanded graphite.

[0007] Physical stirring desulfurization method: A desulfurizing agent is added, and mechanical stirring is used to ensure thorough mixing between the agent and expanded graphite. This allows the desulfurizing agent to react as completely as possible with residual sulfur dioxide and other sulfur impurities in the pores of the expanded graphite. The desulfurizing agent, the separated sulfur-containing solute, and the expanded graphite are then separated by filtration, thus achieving desulfurization. However, current devices in this category rely solely on traditional stirring rods, which makes it difficult for the desulfurizing agent to penetrate deep into the tiny pores of the expanded graphite and fully contact the sulfur impurities. Therefore, the actual desulfurization effect is not ideal.

[0008] In summary, an expanded graphite desulfurization device is still needed to achieve better desulfurization and purification effects. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides an expanded graphite desulfurization and purification device, which solves the problems of introducing impurities, the presence of sulfur dioxide residue, or incomplete impurity removal by stirring in existing technologies.

[0010] According to an embodiment of the present invention, an expanded graphite desulfurization and purification device includes a closed box, the interior of which is divided into a stirring chamber, a washing chamber and a purging chamber from top to bottom, and the stirring chamber, the washing chamber and the purging chamber are interconnected.

[0011] The mixing chamber is equipped with a stirrer, and the top of the box is equipped with a feeding funnel and a feeding pipe, which are respectively connected to the inside of the mixing chamber;

[0012] The cleaning chamber includes at least two interconnected cleaning spaces, and a high-pressure water pump is provided at the connection between the cleaning spaces so that the fluid in the previous cleaning space is drawn into the next cleaning space by high pressure.

[0013] The purging chamber includes a receiving groove, which is a container with an open top and a filter plate at the bottom. The filter plate has a filtration aperture that can separate expanded graphite and cleaning fluid. The bottom of the filter plate is also provided with a suction pipe, the bottom end of which extends out of the box and is connected to a suction pump.

[0014] Furthermore, the stirrer includes a vertically arranged rotating shaft and several stirring paddles mounted on the rotating shaft, with the top end of the rotating shaft extending through the outside of the housing and connected to a first motor.

[0015] Furthermore, the stirring chamber is a cylindrical structure with a tapered bottom and a first valve at the bottom, which is connected to the cleaning chamber.

[0016] Furthermore, the cleaning chamber includes two parallel cleaning spaces connected end-to-end to form a reciprocating closed-loop channel, with a high-pressure water pump independently installed at each end of the connection; one cleaning space is connected to the stirring chamber, and the other cleaning space is connected to the purging chamber.

[0017] Furthermore, the cleaning space is a conical structure with its inner diameter gradually decreasing from one end to the other, and the two cleaning spaces are connected to each other through the end with the smallest diameter and the end with the largest diameter.

[0018] Furthermore, a screw conveyor is also provided inside the cleaning space. The screw conveyor includes a rotating rod and helical blades arranged around the rotating rod. The rotating rod is coaxially arranged with the cleaning space. One end of the rotating rod extends out of the box and is connected to a second motor. The diameter of the helical blades is adaptively adjusted according to the change of the inner diameter of the cleaning space, and a gap is left between the helical blades and the inner wall of the cleaning space.

[0019] Furthermore, an aeration pipe is also installed in the cleaning space. A bubble generator is installed at the end of the aeration pipe located in the cleaning space, and the other end of the aeration pipe extends to the outside of the box and is connected to an air pump.

[0020] Furthermore, the receiving trough is a vertically positioned cylindrical container with an open top, and the side wall of the receiving trough is provided with a discharge pipe that communicates with the cleaning chamber; the filter plate is horizontally positioned and can slide up and down along the receiving trough, while the edge of the filter screen is in a closed sliding connection with the inner wall of the receiving trough, and the lowest position that the filter plate moves to is lower than the connection point of the discharge pipe on the receiving trough.

[0021] Furthermore, the bottom of the filter plate is also provided with a drain funnel. The top diameter of the drain funnel is large and completely covers the bottom surface of the filter plate. A telescopic hose is provided between the drain funnel and the suction pipe. A vertical telescopic rod is provided at the bottom of the receiving tank corresponding to the position below the drain funnel. One end of the telescopic rod is connected to the bottom surface of the receiving tank, and the other end is connected to the bottom surface of the drain funnel, thereby driving the drain funnel and the filter plate to move vertically at the same time.

[0022] Furthermore, horizontally opposite telescopic push rods and conveyor belts are respectively provided on both sides of the top of the receiving groove. The telescopic push rods are fixed at the end away from the receiving groove and a baffle is provided at the end close to the receiving groove. The width of the conveyor belt is not less than the inner diameter of the receiving groove. The top of the conveyor belt is parallel to the top surface of the receiving groove and the bottom surface of the baffle. One end of the conveyor belt extends through the box to the outside. A drying chamber is also provided on the conveyor belt.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The box of the present invention is provided with a stirring chamber, a cleaning chamber and a purging chamber in sequence. The added expanded graphite and desulfurizing agent are first mixed evenly in the stirring chamber by a stirrer, and then enter the cleaning chamber, so that the desulfurizing agent enters the pores of the expanded graphite and reacts fully with the residual sulfur dioxide, dissolving the sulfur dioxide into the solution and separating it from the expanded graphite. Finally, the solid-liquid separation is achieved through the purging chamber, thus realizing the desulfurization of the expanded graphite. This method allows the desulfurizing agent to react better with the sulfur dioxide in the pores inside the expanded graphite, thereby further improving the desulfurization effect.

[0025] 2. The cleaning chamber of the present invention includes at least two interconnected cleaning spaces. A high-pressure water pump is provided at the connection between the cleaning spaces, so that the fluid in the previous cleaning space is drawn into the next cleaning space under high pressure. During the process of the mixture of expanded graphite and desulfurizing agent passing through different cleaning spaces under high pressure, the internal pressure changes from small to large and then back to small. This allows the water-soluble desulfurizing agent to enter the pores of expanded graphite under high pressure and react with sulfur dioxide. Then, the sulfur-containing solution after the reaction is carried out under low pressure, thereby achieving deep cleaning of the internal pores of expanded graphite and greatly improving the desulfurization effect.

[0026] 3. The purging chamber of the present invention includes a receiving tank, a filter plate and a suction pipe. The suction pipe is connected to a suction pump to filter the material inside the receiving tank. By high-pressure suction filtration, the sulfur-containing solution remaining in the pores inside the expanded graphite is extracted at high speed, realizing the separation of sulfur elements from expanded graphite. Excellent desulfurization effect can be achieved without multiple water washing, simplifying the process and reducing water consumption. Attached Figure Description

[0027] Figure 1 This is an overall schematic diagram of an embodiment of the present invention.

[0028] Figure 2 This is a schematic cross-sectional view of the internal structure of an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the purge chamber in an embodiment of the present invention.

[0030] In the above attached diagram: 1. Box body; 2. Mixing chamber; 3. Cleaning chamber; 4. Blowing chamber; 5. Telescopic push rod; 6. Conveyor belt; 7. Drying chamber; 11. Touch screen display; 12. Support leg; 21. Feed funnel; 22. Feed pipe; 23. First motor; 24. Rotating shaft; 25. Stirring paddle; 31. Cleaning space; 32. High-pressure water pump; 33. Rotating rod; 34. Spiral blade; 35. Second motor; 36. Aeration pipe; 41. Discharge pipe; 42. Receiving tank; 43. Filter plate; 44. Filter tube; 45. Drainage funnel; 46. Telescopic hose; 47. Telescopic rod; 51. Baffle plate. Detailed Implementation

[0031] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 As shown in the figure, this invention proposes an expanded graphite desulfurization and purification device, including a closed box 1. The interior of the box 1 is divided into a stirring chamber 2, a cleaning chamber 3, and a purging chamber 4 from top to bottom, and the stirring chamber 2, cleaning chamber 3, and purging chamber 4 are interconnected. In this embodiment, the box 1 is a vertically placed cuboid structure with support feet 12 at its four bottom corners, thereby raising its bottom surface away from the ground. The surface of the box 1 is equipped with a touch screen display, thereby realizing human-machine interaction to control the entire desulfurization process.

[0033] like Figure 2 As shown, a stirrer is installed inside the stirring chamber 2. A feed funnel 21 and a feed pipe 22 are located at the top of the housing 1, both connected to the interior of the stirring chamber 2. The top of the feed funnel 21 can transport the expanded graphite to be desulfurized via a conveyor belt or other conveying equipment, and then add it into the stirring chamber 2 through the feed funnel 21. The feed pipe 22 is connected to a storage tank containing desulfurizing agent for injection. Preferably, the stirring chamber 2 has a cylindrical structure with a tapered bottom, which allows for better discharge of the mixture of expanded graphite and desulfurizing agent into the cleaning chamber 3. A first valve is located at the bottom of the stirring chamber 2 and is connected to the cleaning chamber 3. The first valve is closed during stirring and opened after stirring to discharge the material into the cleaning chamber 3.

[0034] In a further embodiment, the agitator includes a vertically arranged rotating shaft 24 and several agitator blades 25 mounted on the rotating shaft 24. The top end of the rotating shaft 24 extends through the outside of the housing 1 and is connected to a first motor 23. The first motor 23 drives the rotating shaft 24 and the agitator blades 25 to rotate, thereby causing the desulfurizing agent and expanded graphite inside the mixing chamber 2 to rotate and mix, so that they are premixed evenly and achieve the reaction of most of the sulfur dioxide.

[0035] The cleaning chamber 3 includes at least two interconnected cleaning spaces 31. A high-pressure water pump 32 is installed at the connection between the cleaning spaces 31, causing the fluid in the preceding cleaning space 31 to be drawn into the following cleaning space 31 under high pressure. Specifically, in this embodiment, the cleaning chamber 3 includes two parallel cleaning spaces 31, which are connected end-to-end to form a reciprocating closed-loop channel. A high-pressure water pump 32 is independently installed at each connection point. One cleaning space 31 is connected to the stirring chamber 2 through a first valve, and the other cleaning space 31 is connected to the purging chamber 4 through a second valve. That is, the mixture of expanded graphite and desulfurizing agent circulates back and forth in the two cleaning spaces 31. Each time it passes through the connection point, it is subjected to the pressure of the high-pressure water pump 32, which causes the desulfurizing agent to penetrate into the internal pores of the expanded graphite and fully contact and react with the residual sulfur dioxide.

[0036] Preferably, the cleaning space 31 has a conical structure with its inner diameter gradually decreasing from one end to the other, and the two cleaning spaces 31 are connected to each other through the end with the smallest diameter and the end with the largest diameter, respectively. In actual operation, the end with the larger diameter is the beginning and the end with the smaller diameter is the end. In this way, the material moves towards the end with the smaller diameter inside the cleaning space 31, and the pressure gradually increases, which can better promote the mixing of the desulfurizing agent and the expanded graphite. At the same time, after passing through the connection point, it enters the larger diameter area of ​​the next cleaning space 31, where the pressure drops rapidly. This allows the sulfur dioxide and desulfurizing agent compressed in the pores of the expanded graphite to expand and be discharged quickly, which is conducive to the complete separation of the remaining residual sulfur compounds from the expanded graphite.

[0037] In addition, a screw conveyor is installed inside the cleaning space 31. The screw conveyor includes a rotating rod 33 and helical blades 34 arranged around the rotating rod 33. The rotating rod 33 is coaxially arranged with the cleaning space 31, and one end of the rotating rod 33 extends out of the housing 1 and is connected to a second motor 35. The diameter of the helical blades 34 is adaptively adjusted according to the change of the inner diameter of the cleaning space 31, and a gap is left between the helical blades 34 and the inner wall of the cleaning space 31. The operation of the screw conveyor can further drive the material inside the cleaning space 31 to move towards the tail end, and while increasing the internal pressure of the material, it can achieve further stirring and shearing, thus better promoting the mixing of the desulfurizing agent and expanded graphite.

[0038] An aeration pipe 36 is also installed within the cleaning space 31. A bubble generator is located at one end of the aeration pipe 36 within the cleaning space 31, and the other end of the aeration pipe 36 extends to the outside of the housing 1 and is connected to an air pump. The aeration pipe 36 introduces additional fine bubbles. These bubbles move and burst in the liquid, generating shock waves and shear forces that create microscopic turbulence. This continuous disturbance disrupts the liquid film at the pore openings, accelerating liquid exchange between the inside and outside of the pores. It continuously pumps fresh solution rich in desulfurizing agent into the pores while simultaneously carrying out solution containing dissolved impurities. Furthermore, the powerful shock waves generated when the bubbles burst physically peel off and wash away sulfur-containing impurities attached to or adsorbed on the inner wall of the pores, achieving a cavitation effect similar to that in ultrasonic cleaning, further enhancing the desulfurization effect.

[0039] The purging chamber 4 includes a receiving tank 42, which is a container with an open top. A filter plate 43 is installed at the bottom of the receiving tank 42. The filter plate 43 has pores large enough to separate expanded graphite and cleaning fluid. A suction pipe 44 is also installed at the bottom of the filter plate 43. The bottom end of the suction pipe 44 extends outside the housing 1 and is connected to a suction pump. When the suction pump is running, high-pressure suction is used to extract the sulfur-containing solution remaining in the pores of the expanded graphite at high speed, thus achieving the separation of sulfur from the expanded graphite.

[0040] Specifically, the receiving trough 42 is a vertically oriented cylindrical container with an open top. A discharge pipe 41 is provided on the side wall of the receiving trough 42, connecting it to the cleaning chamber 3. The filter plate 43 is horizontally positioned and can slide up and down along the receiving trough 42. Simultaneously, the edge of the filter screen is slidably connected to the inner wall of the receiving trough 42 in a closed manner. The lowest position reached by the filter plate 43 is lower than the connection point of the discharge pipe 41 on the receiving trough 42. Before material is added, the filter plate 43 is at its lowest position, maximizing the capacity of the receiving trough 42 above it, fully accommodating the material inside the cleaning chamber 3. After filtration is complete, the filter plate 43 rises to its highest position, allowing the filter cake formed by the expanded graphite on the filter plate 43 to move to the top of the receiving trough 42, where it can be removed for subsequent drying.

[0041] In conjunction with this, a drain funnel 45 is provided at the bottom of the filter plate 43. The drain funnel 45 has a large top diameter and completely covers the bottom surface of the filter plate 43. A telescopic hose 46 is provided between the drain funnel 45 and the suction pipe 44. A vertical telescopic rod 47 is provided at the bottom of the receiving groove 42, corresponding to the position below the drain funnel 45. One end of the telescopic rod 47 is connected to the bottom surface of the receiving groove 42, and the other end is connected to the bottom surface of the drain funnel 45, thereby driving the drain funnel 45 and the filter plate 43 to move vertically simultaneously. That is, the desulfurizing agent solution extracted by suction enters the suction pipe 44 through the drain funnel 45 and the telescopic hose 46 and is discharged to the outside. The telescopic hose 46 can be telescopically connected during the up-and-down movement of the drain funnel 45 and the filter plate 43 driven by the telescopic rod 47.

[0042] like Figure 3 As shown in the further embodiment, the top of the receiving groove 42 is provided with horizontally opposite telescopic push rods 5 and conveyor belts 6 on both sides. The telescopic push rods 5 are fixed at the end away from the receiving groove 42 and a baffle 51 is provided at the end near the receiving groove 42. The width of the conveyor belt 6 is not less than the inner diameter of the receiving groove 42. The top of the conveyor belt 6 is parallel to the top surface of the receiving groove 42 and the bottom surface of the baffle 51. One end of the conveyor belt 6 extends through the box 1 to the outside. A drying chamber 7 is also provided on the conveyor belt 6. When the expanded graphite filter cake moves to the top of the receiving groove 42, the telescopic push rods 5 work to push the filter cake horizontally onto the conveyor belt 6 through the baffle 51. Then the conveyor belt 6 starts to run, so that the filter cake moves horizontally. The filter cake is dried by high-temperature hot air during the process of passing through the drying chamber 7. Finally, it leaves from the end of the conveyor belt 6 and enters the collection device for subsequent processing. In this way, the cleaning and drying process of expanded graphite can be completed in one go, improving the automation effect.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An expanded graphite desulfurization and purification device, characterized in that: It includes a closed box, the interior of which is divided into a stirring chamber, a cleaning chamber and a purging chamber from top to bottom, and the stirring chamber, the cleaning chamber and the purging chamber are interconnected. The mixing chamber is equipped with a stirrer, and the top of the box is equipped with a feeding funnel and a feeding pipe, which are respectively connected to the inside of the mixing chamber; The cleaning chamber includes at least two interconnected cleaning spaces, and a high-pressure water pump is provided at the connection between the cleaning spaces so that the fluid in the previous cleaning space is drawn into the next cleaning space by high pressure. The purging chamber includes a receiving groove, which is a container with an open top and a filter plate at the bottom. The filter plate has a filtration aperture that can separate expanded graphite and cleaning fluid. The bottom of the filter plate is also provided with a suction pipe, the bottom end of which extends out of the box and is connected to a suction pump.

2. The expanded graphite desulfurization and purification device as described in claim 1, characterized in that: The agitator includes a vertically arranged rotating shaft and several agitator blades mounted on the rotating shaft. The top end of the rotating shaft extends through the outside of the housing and is connected to a first motor.

3. The expanded graphite desulfurization and purification device as described in claim 1, characterized in that: The stirring chamber is a cylindrical structure with a tapered bottom. A first valve is located at the bottom and is connected to the cleaning chamber through the first valve.

4. The expanded graphite desulfurization and purification device as described in claim 1, characterized in that: The cleaning chamber includes two parallel cleaning spaces connected end-to-end to form a closed-loop channel for reciprocating circulation. A high-pressure water pump is independently installed at the connection point. One cleaning space is connected to the stirring chamber, and the other cleaning space is connected to the purging chamber.

5. The expanded graphite desulfurization and purification device as described in claim 4, characterized in that: The cleaning space is a conical structure with its inner diameter gradually decreasing from one end to the other, and the two cleaning spaces are connected to each other through the end with the smallest diameter and the end with the largest diameter.

6. The expanded graphite desulfurization and purification device as described in claim 5, characterized in that: The cleaning space is also equipped with a screw conveyor, which includes a rotating rod and helical blades arranged around the rotating rod. The rotating rod is coaxial with the cleaning space, and one end of the rotating rod extends out of the box and is connected to a second motor. The diameter of the helical blades is adaptively adjusted according to the change of the inner diameter of the cleaning space, and a gap is left between the helical blades and the inner wall of the cleaning space.

7. The expanded graphite desulfurization and purification device as described in claim 4, characterized in that: An aeration pipe is also installed in the cleaning space. A bubble generator is installed at the end of the aeration pipe located in the cleaning space, and the other end of the aeration pipe extends to the outside of the box and is connected to an air pump.

8. The expanded graphite desulfurization and purification device as described in claim 1, characterized in that: The receiving trough is a vertically positioned cylindrical container with an open top. The side wall of the receiving trough is provided with a discharge pipe that communicates with the cleaning chamber. The filter plate is horizontally positioned and can slide up and down along the receiving trough. At the same time, the edge of the filter screen is slidably connected to the inner wall of the receiving trough in a closed manner. The lowest position that the filter plate moves to is lower than the connection point of the discharge pipe on the receiving trough.

9. The expanded graphite desulfurization and purification device as described in claim 8, characterized in that: The bottom of the filter plate is also provided with a drain funnel. The top of the drain funnel has a large diameter and completely covers the bottom surface of the filter plate. A telescopic hose is provided between the drain funnel and the suction pipe. A vertical telescopic rod is provided at the bottom of the receiving tank corresponding to the position below the drain funnel. One end of the telescopic rod is connected to the bottom surface of the receiving tank, and the other end is connected to the bottom surface of the drain funnel, thereby driving the drain funnel and the filter plate to move vertically at the same time.

10. The expanded graphite desulfurization and purification device as described in claim 8, characterized in that: The receiving groove has horizontally opposite telescopic push rods and conveyor belts on both sides of its top. The telescopic push rods are fixed at the end away from the receiving groove and a baffle is provided at the end near the receiving groove. The width of the conveyor belt is not less than the inner diameter of the receiving groove. The top of the conveyor belt is parallel to the top surface of the receiving groove and the bottom surface of the baffle. One end of the conveyor belt extends through the box to the outside. A drying chamber is also provided on the conveyor belt.

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