Sodium sulfate step-by-step freezing crystallization device

Abstract

The utility model provides a sodium sulfate step-by-step freezing crystallization device which comprises a raw material tank and a pushing assembly, the pushing assembly is installed in the middle of the top end of the raw material tank, a motor is movably installed in the middle of the left end of the raw material tank, a rotating shaft is rotatably installed at the output end of the motor, and fixing blocks are installed at the two ends of the rotating shaft through bolts. A hydraulic cylinder is movably mounted in the middle of the right end of the raw material tank, a telescopic rod is movably mounted at the output end of the hydraulic cylinder, a supporting plate is fixedly mounted at the lower middle end of the inner wall of the raw material tank, a mounting groove is formed in the surface of the supporting plate, and a drainage pipe is fixedly mounted at the bottom end of the right side of the raw material tank. According to the sodium sulfate step-by-step freezing crystallization device, organic matter contained in the freezing crystallization process can be prevented from influencing the purity of sodium sulfate freezing crystallization salt along with continuous backflow of crystallization mother liquor, meanwhile, precipitated sodium sulfate crystals can be cleaned, and the effect that a cold separation tank system is prevented from scaling is achieved.

Description

Technical Field

[0001] This utility model relates to the field of freeze crystallization technology, and more specifically, to a sodium sulfate step-by-step freeze crystallization apparatus. Background Technology

[0002] With the development of industrial technology, the discharge of wastewater, waste gas, and waste from various industries is constantly increasing. Due to increasingly stringent environmental standards and limited environmental capacity in some areas, the demand for zero-discharge technology for industrial wastewater has increased significantly. Industrial wastewater, after concentration, forms a mixed solution of sodium chloride and sodium sulfate, and also contains a certain amount of biodegradable organic matter. Sodium chloride, sodium sulfate, and organic matter can be separated using nanofiltration membranes. The resulting nanofiltration permeate mainly contains sodium chloride and a small amount of small-molecule organic matter. The nanofiltration concentrate contains sodium sulfate and a large amount of relatively large-molecule organic matter. Sodium sulfate in the nanofiltration concentrate can be separated using freeze crystallization technology. Freeze crystallization involves cooling the nanofiltration concentrate to a certain temperature. Temperature is a critical factor. Sodium sulfate's solubility is highly sensitive to temperature; when the temperature drops to a suitable level, it crystallizes and precipitates, separating from the nanofiltration concentrate. In practice, part of the crystallization mother liquor after sodium sulfate separation is refluxed and mixed with the un-crystallized nanofiltration concentrate; the other part is discharged. Since the nanofiltration concentrate may contain organic matter whose solubility doesn't significantly change with temperature, this organic matter remains in the crystallization mother liquor during the freeze-crystallization process. As the crystallization mother liquor is continuously refluxed and mixed with the nanofiltration concentrate, the organic matter content in the nanofiltration concentrate to be frozen increases. When the organic matter content reaches a certain level, it will precipitate along with the sodium sulfate, ultimately affecting the purity of the frozen-crystallized sodium sulfate salt.

[0003] To address the aforementioned issues, current ozone delivery methods, which rely solely on pipelines, fail to allow ozone to remain in the liquid for extended periods. This results in insufficient oxidation and removal of organic matter in the nanofiltration concentrate awaiting freezing and crystallization in the raw material tank, leading to ozone waste. Extensive research revealed a sodium sulfate freezing and crystallization system (patent number CN219231474U). This system includes a raw material tank with a push assembly fixedly connected to its top. An air inlet pipe connects to the side of the tank, and a connecting pipe is spirally connected to the other end. A hollow disc is fixedly connected above the connecting pipe, and evenly distributed exhaust pipes are fixedly connected to the top of the hollow disc. The interior of the raw material tank is fixedly connected to… The support rod has a cover fixedly connected to its other end. This invention delivers ozone through an inlet pipe to the inside of a connecting pipe, then through the connecting pipe to the inside of a hollow disc, and finally through an exhaust pipe into the inside of a raw material tank. At this point, ozone bubbles accumulate at the bottom of the cover to fully react with the organic matter inside the raw material tank. This setup ensures that the ozone and organic matter are in full contact and react, avoiding resource waste. However, the technical solution provided by this patent is problematic because the organic matter contained in the freeze-crystallization process easily forms scale and adheres to the inner wall as the mother liquor continuously flows back. Over time, this hinders the removal of sodium sulfate and affects the purity of the next round of sodium sulfate freeze-crystallized salt.

[0004] This invention can prevent the organic matter contained in the freeze crystallization process from affecting the purity of the sodium sulfate freeze crystallized salt as the mother liquor is continuously refluxed. At the same time, it can clean the precipitated sodium sulfate crystals and prevent scaling in the freeze crystallization tank system. Utility Model Content

[0005] The present invention aims to solve the technical problems mentioned in the background art and provide a sodium sulfate step-by-step freezing crystallization device.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a sodium sulfate stepwise freeze crystallization device, comprising: a raw material tank and a pushing assembly; the pushing assembly is installed at the top center of the raw material tank; a motor is movably installed at the left center of the raw material tank; a rotating shaft is rotatably installed at the output end of the motor; fixing blocks are installed at both ends of the rotating shaft by bolts; a spiral disk is movably installed on the outer surface of the rotating shaft; a fixing plate is fixedly connected to the left end of the telescopic rod; a hydraulic cylinder is movably installed at the right center of the raw material tank; a telescopic rod is movably installed at the output end of the hydraulic cylinder; a support plate is fixedly installed at the lower middle end of the inner wall of the raw material tank; an installation groove is formed on the surface of the support plate; and a drain pipe is fixedly installed at the bottom right end of the raw material tank.

[0007] A further preferred embodiment: a spring is movably mounted on the right end of the fixing plate, the number of the springs being four, radially distributed around the telescopic rod, and the springs being made of stainless steel.

[0008] A further preferred embodiment: the longitudinal section of the mounting groove is trapezoidal, the mounting grooves are arranged in a rectangular array, and a limiting block is fixedly installed on the surface of the mounting groove, the limiting block being conical in shape.

[0009] A further preferred embodiment: a temperature controller is movably installed on the top left side of the raw material tank, and a cooling pipe is fixedly installed at the bottom of the temperature controller. The cooling pipe is U-shaped, and the raw material tank and the cooling pipe are arranged opposite to each other.

[0010] A further preferred embodiment: the rotating shaft is telescopically oriented, and the spiral disk and the rotating shaft are connected in cooperation.

[0011] A further preferred embodiment: the bottom end of the support plate is engaged with a filter screen, the gap size of the filter screen is 3mm to 5mm, and the filter screen is made of stainless steel.

[0012] A further preferred embodiment: the fixing plate and the fixing block are in sealed communication.

[0013] Beneficial effects:

[0014] 1. By installing a temperature controller with a cooling pipe fixed at the bottom, sodium sulfate can crystallize and precipitate when the temperature controller drops to a suitable temperature. At the same time, the cooling pipe prolongs the cooling effect, keeping the inside of the cold precipitation tank at a low temperature and reducing the temperature of the circulating solution. The temperature inside the raw material tank is adjusted by the temperature controller to clean the sodium sulfate crystal layer and prevent scaling in the cold precipitation tank system.

[0015] 2. By setting up a support plate, filter screen, and limiting block, a force is applied to squeeze the fixed block, causing the rotating shaft and spiral disk to contract under force. The sodium sulfate crystal layer on the outer surface is crushed and falls into the support plate. Large pieces of sodium sulfate crystal layer fall onto the conical limiting block, where they are broken into small fragments by impact and fall into the installation groove. The filter screen is made of stainless steel to intercept the sodium sulfate crystal layer and prevent large pieces of sodium sulfate crystal layer from falling onto the exhaust pipe. At the same time, stainless steel does not react chemically with sodium sulfate, which helps to improve the purity of the frozen crystallized salt and extend the service life of the exhaust pipe and filter screen.

[0016] 3. By setting up a spiral disc and a rotating shaft, with the rotating shaft being telescopic and the spiral disc and rotating shaft being connected in cooperation, the hydraulic cylinder drives the telescopic rod to extend and retract forward, driving the fixed plate. By applying force to squeeze the fixed block, the rotating shaft and spiral disc are compressed under force, and the sodium sulfate crystal layer on the outer surface is crushed and falls into the support plate. At the same time, the motor can also drive the rotating shaft to rotate. The stirring device can provide a good stirring effect for the entire raw material tank and form a circulation power, which improves the liquid circulation rate and circulation flow rate in the raw material tank, thereby ensuring the crystallization efficiency and crystal quality of the entire raw material tank.

[0017] 4. In summary, this sodium sulfate staged freeze crystallization device, equipped with a temperature controller, support plate, filter screen, limiting block, spiral disk, and rotating shaft, can prevent organic matter contained in the freeze crystallization process from affecting the purity of the sodium sulfate freeze crystallized salt as the mother liquor continuously flows back. At the same time, it can clean the precipitated sodium sulfate crystals and prevent scaling in the cold precipitation tank system. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural diagram of the present invention.

[0019] Figure 2 This is a three-dimensional structural diagram of the support plate of this utility model.

[0020] Figure 3 This is a three-dimensional structural diagram of the rotating shaft, spiral disk, and fixing block of this utility model.

[0021] Figure 4 For the utility model Figure 1 A magnified structural diagram at point A.

[0022] Figure 1-4 In the middle: 1-Raw material tank, 2-Pushing component, 3-Motor, 5-Rotating shaft, 501-Spiral disc, 6-Fixing block, 7-Fixing plate, 8-Telescopic rod, 9-Spring, 10-Hydraulic cylinder, 11-Support plate, 101-Mounting groove, 102-Limit block, 103-Filter screen, 12-Drain pipe, 13-Temperature controller. Detailed Implementation

[0023] The following will refer to the appendix in the embodiments of this utility model. Figure 1-Figure 4 The technical solutions in the embodiments of this utility model will be clearly and completely described.

[0024] Please see Figure 1-4In this embodiment of the present invention, a sodium sulfate step-by-step freezing crystallization device includes: a raw material tank 1 and a pushing component 2. The pushing component 2 is installed at the top center of the raw material tank 1. A motor 3 is movably installed at the left center of the raw material tank 1. A rotating shaft 5 is rotatably installed at the output end of the motor 3. Fixing blocks 6 are installed at both ends of the rotating shaft 5 by bolts. A spiral disk 501 is movably installed on the outer surface of the rotating shaft 5. A fixing plate 7 is fixedly connected to the left end of the telescopic rod 8. A hydraulic cylinder 10 is movably installed at the right center of the raw material tank 1. A telescopic rod 8 is movably installed at the output end of the hydraulic cylinder 10. A support plate 11 is fixedly installed at the lower middle end of the inner wall of the raw material tank 1. An installation groove 101 is opened on the surface of the support plate 11. A drain pipe 12 is fixedly installed at the bottom right end of the raw material tank 1.

[0025] In this embodiment of the utility model, a spring 9 is movably installed on the right end of the fixing plate 7. There are four springs 9, which are radially distributed around the telescopic rod 8. The springs 9 are made of stainless steel. The hydraulic cylinder 10 drives the telescopic rod 8 to extend and retract forward, thereby driving the fixing plate 7. By applying force, the plate 7 is pressed against the fixing block 6, and the springs fix the telescopic rod 8 under their action. At the same time, the springs 9 have a shock absorption function.

[0026] In this embodiment of the utility model, the longitudinal section of the mounting groove 101 is trapezoidal, and the mounting groove 101 is distributed in a rectangular array. A limiting block 102 is fixedly installed on the surface of the mounting groove 101. The limiting block 102 is conical in shape. When a force is applied to press against the fixed block 6, the rotating shaft 5 and the spiral disk 501 are compressed by the force. The sodium sulfate crystal layer on the outer surface is crushed by the compression and falls into the support plate 11. Large pieces of sodium sulfate crystal layer fall onto the conical limiting block and are broken into small fragments by impact, falling into the mounting groove 101.

[0027] In this embodiment of the present invention, a temperature controller 13 is movably installed on the top left side of the raw material tank 1, and a cooling pipe is fixedly installed at the bottom of the temperature controller 13. The cooling pipe is U-shaped, and the temperature controller 13 and the cooling pipe are arranged opposite to each other. When the temperature controller 13 drops to a suitable temperature, sodium sulfate can crystallize and precipitate. At the same time, the cooling pipe prolongs the cooling effect, so that the inside of the cold precipitation tank 1 is in a low temperature state and the temperature of the circulating solution decreases.

[0028] In this embodiment of the utility model, the rotating shaft 5 is telescopically oriented, and the spiral disk 501 is connected to the rotating shaft 5. The hydraulic cylinder 10 drives the telescopic rod 8 to extend and retract forward, driving the fixed plate 7. By applying force, the plate is squeezed against the fixed block 6. The rotating shaft 5 and the spiral disk 501 are compressed by force, and the sodium sulfate crystal layer on the outer surface is crushed and falls into the support plate 11. At the same time, the motor 3 can also drive the rotating shaft 5 to rotate. The stirring device can provide a good stirring effect for the entire raw material tank 1 and form a circulating power, which improves the liquid circulation rate and circulation flow rate in the raw material tank 1, thereby ensuring the crystallization efficiency and crystal quality of the entire raw material tank 1.

[0029] In this embodiment of the utility model, a filter screen 103 is engaged with the bottom end of the support plate 11. The gap size of the filter screen 103 is 3mm to 5mm. The filter screen 103 is made of stainless steel and is used to intercept sodium sulfate crystal layers to prevent large pieces of sodium sulfate crystal layers from falling onto the exhaust pipe. At the same time, stainless steel does not react chemically with sodium sulfate, which helps to improve the purity of the frozen crystallized salt and extend the service life of the exhaust pipe and the filter screen 103.

[0030] In this embodiment of the utility model, the fixing plate 7 and the fixing block 6 are sealed and connected, making the connection between the fixing plate 7 and the fixing block 6 very stable. The hydraulic cylinder 10 drives the telescopic rod 8 to extend and retract forward, thereby driving the fixing plate 7. By applying force, it squeezes the fixing block 6. The sealed connection facilitates its replacement and maintenance, effectively avoiding the waste of resources.

[0031] Working principle: Hydraulic cylinder 10 drives telescopic rod 8 to extend and retract forward, driving fixed plate 7. By applying force, it presses against fixed block 6, which, under the action of spring, fixes telescopic rod 8. At the same time, spring 9 has a shock absorption function. Shaft 5 and spiral disk 501 contract under force, and the sodium sulfate crystal layer on the outer surface is crushed and falls into support plate 11. Large pieces of sodium sulfate crystal layer fall onto the conical limiting block, and are broken into small fragments by impact, falling into installation groove 101. Filter screen 103 is used to intercept sodium sulfate crystal layer, preventing large pieces of sodium sulfate crystal layer from falling onto exhaust pipe. At the same time, stainless steel does not react chemically with sodium sulfate, which helps to improve the purity of frozen crystallized salt and extend the service life of exhaust pipe and filter screen 103. Meanwhile, motor 3 can also drive rotating shaft 5 to rotate. The stirring device can provide a good stirring effect for the entire raw material tank 1 and form a circulating power. This improves the liquid circulation rate and flow rate in raw material tank 1, thereby ensuring the crystallization efficiency and quality of the entire raw material tank 1. The temperature controller 13 is set opposite to the cooling pipe. When the temperature controller 13 drops to a suitable temperature, sodium sulfate can crystallize and precipitate. At the same time, the cooling pipe prolongs the cooling effect, keeping the interior of the cold precipitation tank 1 at a low temperature and reducing the temperature of the circulating solution. The temperature inside the raw material tank 1 is adjusted by the temperature controller 13. When the temperature of the temperature controller 13 is 70°+, the sodium sulfate crystal layer is concentrated. When the temperature of the temperature controller 13 is 35°-, the sodium sulfate crystal layer is filtered into water molecules and discharged from the drain pipe 12, which facilitates the cleaning of the sodium sulfate crystal layer. It can also prevent the organic matter contained in the freezing crystallization process from affecting the purity of the sodium sulfate freezing crystallized salt as the mother liquor is continuously refluxed. At the same time, it can clean the precipitated sodium sulfate crystals and prevent scaling in the cold precipitation tank system.

Claims

1. A stepwise cryo-crystallization apparatus for sodium sulfate, comprising: A raw material tank (1) and a pushing assembly (2), wherein the pushing assembly (2) is installed at the top center of the raw material tank (1), characterized in that: a motor (3) is movably installed at the left center of the raw material tank (1), a rotating shaft (5) is rotatably installed at the output end of the motor (3), a fixing block (6) is installed at both ends of the rotating shaft (5) by bolts, a spiral disk (501) is movably installed on the outer surface of the rotating shaft (5), a fixing plate (7) is fixedly connected to the left end of the telescopic rod (8), a hydraulic cylinder (10) is movably installed at the right center of the raw material tank (1), a telescopic rod (8) is movably installed at the output end of the hydraulic cylinder (10), a support plate (11) is fixedly installed at the lower middle end of the inner wall of the raw material tank (1), an installation groove (101) is opened on the surface of the support plate (11), and a drain pipe (12) is fixedly installed at the bottom right end of the raw material tank (1).

2. The sodium sulfate stepwise cryo-crystallization apparatus according to claim 1, characterized in that: A spring (9) is movably installed on the right end of the fixed plate (7). There are four springs (9) that are radially distributed around the telescopic rod (8). The springs (9) are made of stainless steel.

3. The sodium sulfate stepwise freeze crystallization apparatus according to claim 1, characterized in that: The longitudinal section of the mounting groove (101) is trapezoidal, and the mounting groove (101) is arranged in a rectangular array. A limiting block (102) is fixedly installed on the surface of the mounting groove (101), and the limiting block (102) is conical in shape.

4. The sodium sulfate stepwise freeze crystallization apparatus according to claim 1, characterized in that: A temperature controller (13) is movably installed on the top left side of the raw material tank (1), and a cooling pipe is fixedly installed at the bottom of the temperature controller (13). The cooling pipe is U-shaped, and the raw material tank (1) and the cooling pipe are arranged opposite to each other.

5. The sodium sulfate stepwise freeze crystallization apparatus according to claim 1, characterized in that: The rotating shaft (5) is telescopically oriented, and the spiral disk (501) and the rotating shaft (5) are connected in cooperation.

6. The sodium sulfate stepwise freeze crystallization apparatus according to claim 1, characterized in that: The bottom end of the support plate (11) is engaged with a filter screen (103), the gap size of the filter screen (103) is 3mm to 5mm, and the material of the filter screen (103) is stainless steel.

7. The sodium sulfate stepwise freeze crystallization apparatus according to claim 1, characterized in that: The fixing plate (7) and the fixing block (6) are sealed and connected.

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