Cooling crystallization device in sodium sulfate production

Abstract

According to the cooling crystallization device in sodium sulfate production provided by the invention, the crystallization device is arranged, a sodium sulfate supersaturated solution is introduced into the crystallization pipe, and the sodium sulfate supersaturated solution in the crystallization pipe is crystallized by utilizing a low-temperature heat exchange medium supplied by the heat exchange medium production device; the method comprises the following steps: cooling and crystallizing a supersaturated sodium sulfate solution, transferring the crystallized material into a filter for solid-liquid separation, returning the separated mother liquor to a material storage tank for crystallization of the next round, and returning the heat exchange medium after heat exchange to a heat exchange medium production device for regeneration. And continuous crystallization of the supersaturated sodium sulfate solution is realized by utilizing the crystallization pipe, so that the defects that the crystallization efficiency is low and the production efficiency is influenced in a traditional intermittent crystallization mode by adopting a crystallization kettle are overcome.

Description

Technical Field

[0001] The present application relates to the technical field of chemical raw material preparation, and in particular to a cooling crystallization device for sodium sulfate production. Background Art

[0002] Sodium sulfate, also known as sodium sulfate, is an inorganic compound with the chemical formula Na2SO4 and a molecular weight of 142.04. It appears as white, odorless, bitter crystals or powder that is hygroscopic. It appears as colorless, transparent, large crystals or small granular crystals. Sodium sulfate has a wide range of applications and is commonly used in the production of water glass, pulping, porcelain glaze, detergents, refrigerant mixtures, desiccants, analytical chemical reagents, dye diluents, pharmaceuticals, and more. It is primarily used as a filler in synthetic detergents; in the papermaking industry, it is used as a cooking agent in sulfate pulping; in the glass industry, it is used to replace soda ash; in the chemical industry, it is used as a raw material for sodium sulfide, sodium silicate, and other chemical products; in the textile industry, it is used to prepare vinylon spinning coagulation baths; in the pharmaceutical industry, it is used as a laxative; and it is also used in nonferrous metallurgy and leather.

[0003] At present, the raw materials for producing sodium sulfate mainly include natural thenardite as raw material, salt lake brine as raw material, calcium thenardite as raw material, sodium sulfate type well salt mine brine as raw material, sea salt bittern as raw material, and hydrochloric acid, cellulose, papermaking and other by-products as raw materials. Although the raw material sources for preparing sodium sulfate are extensive, the preparation of high-purity sodium sulfate still requires a complicated process. The existing common practice is to first dissolve the raw materials and then cool them down to obtain high-purity sodium sulfate decahydrate, also known as thenardite, and then dissolve the thenardite and heat it to evaporate and crystallize to prepare sodium sulfate. Therefore, dissolving the raw materials and cooling and crystallizing them to prepare thenardite is a pre-step to obtain high-purity sodium sulfate, and is also an important part of the process for preparing high-purity sodium sulfate. The existing method for preparing thenardite crystallization is carried out in a crystallization kettle, but this crystallization method is carried out intermittently, which inevitably leads to low crystallization efficiency and affects production efficiency. Utility Model Content

[0004] The present application provides a cooling crystallization device for sodium sulfate production, which is used to solve the problem that the existing method of preparing sodium sulfate crystals using a crystallization kettle is intermittent, resulting in low crystallization efficiency and affecting production efficiency.

[0005] The present application provides a cooling crystallization device for sodium sulfate production, comprising a crystallization device, wherein a crystallization tube is provided in the crystallization device; both ends of the crystallization tube extend out of the crystallization device;

[0006] The heat exchange medium input end of the crystallization tube is connected to the circulation pump and the heat exchange medium production device in sequence; the material input end of the crystallization tube is connected to the liquid transfer pump and the material storage tank in sequence;

[0007] The heat exchange medium output end of the crystallization tube is connected to the input end of the heat exchange medium production device; the material output end of the crystallization tube is connected to the filter and the material storage tank in sequence;

[0008] A heat exchange medium inlet is provided at the lower part of one side of the crystallization device, and a heat exchange medium outlet is provided at the upper part; the heat exchange medium inlet is connected to the circulation pump and the heat exchange medium production device in sequence; the heat exchange medium outlet is connected to the input end of the heat exchange medium production device.

[0009] Optionally, the crystallization tube is coiled and folded in multiple layers, and the crystallization tube includes an outer tube and an inner tube that are coaxially arranged;

[0010] The outer tube includes a straight outer tube and a curved outer tube, and adjacent straight outer tubes are connected end to end through the curved outer tubes;

[0011] Both ends of the outer tube are closed, and a material inlet and a material outlet are respectively opened on the tube wall at both ends. The material inlet is connected to the output end of the liquid transfer pump; the material outlet is connected to the material input end of the filter.

[0012] Optionally, the inner tube includes a straight inner tube and a curved inner tube, and adjacent straight inner tubes are connected end to end via the curved inner tubes;

[0013] One end of the inner tube is an inlet, and the other end is an outlet. The inlet is connected to the output end of the circulation pump, and the outlet is connected to the heat exchange medium production device.

[0014] Optionally, a spiral belt is wound around the outer circumference of the straight portion inner tube along the length direction of the straight portion inner tube.

[0015] Optionally, the filter comprises a housing, wherein the interior of the housing is divided into an upper liquid inlet area and a lower mother liquid area by a filter layer;

[0016] A funnel is provided on the lower surface of the filter layer to support the filter layer and guide the mother liquid;

[0017] A discharge port is provided on one side wall of the liquid inlet area of ​​the shell near the filter layer;

[0018] A liquid inlet is provided on the top of the shell and is connected to the material output end of the crystallization tube; a liquid discharge port is provided at the bottom of the shell and is connected to the material storage tank.

[0019] Optionally, a vacuum port is provided on one side wall of the mother liquid region of the shell near the filter layer and is connected to a vacuum pump.

[0020] Optionally, the heat exchange medium production device includes a device body, which is divided into a heat exchange medium storage area and a heat exchange medium production area by a partition;

[0021] An overflow port is provided on the partition to connect the heat exchange medium storage area and the heat exchange medium production area;

[0022] A medium outlet is provided on one side of the device body where the heat exchange medium storage area is located and is connected to the input end of the circulation pump;

[0023] The heat exchange medium production area is provided with a heat exchange coil in the device body, and the heat exchange coil is connected in series with the cold source to form a loop;

[0024] A medium inlet connected to the heat exchange medium outlet and the heat exchange medium output end of the crystallization tube is provided at the lower part of one side surface of the device body of the heat exchange medium production area.

[0025] The cooling crystallization device for sodium sulfate production provided in the present application is provided with a crystallization device, a supersaturated sodium sulfate solution is passed into a crystallization tube, and the supersaturated sodium sulfate solution in the crystallization tube is crystallized using a low-temperature heat exchange medium supplied by a heat exchange medium production device. The crystallized material is transferred to a filter for solid-liquid separation, and the mother liquor after separation is returned to the material storage tank for the next round of crystallization, while the heat exchange medium after heat exchange is returned to the heat exchange medium production device for regeneration. The device of the present application, through the coordinated use of the above-mentioned equipment, cools and crystallizes the supersaturated sodium sulfate solution, and uses the crystallization tube to achieve continuous crystallization of the supersaturated sodium sulfate solution, thereby overcoming the disadvantages of the traditional intermittent crystallization method using a crystallization kettle, which has low crystallization efficiency and affects production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 A schematic diagram of a cooling crystallization device for sodium sulfate production provided in one embodiment of the present application;

[0028] Figure 2 A schematic structural diagram of a crystallization tube provided in one embodiment of the present application;

[0029] Figure 3 A schematic structural diagram of a straight inner tube provided in one embodiment of the present application;

[0030] Figure 4 A schematic diagram of the structure of a filter provided in one embodiment of the present application;

[0031] Figure 5 A schematic structural diagram of a filter provided in another embodiment of the present application;

[0032] Figure 6 A schematic structural diagram of a heat exchange medium production device provided in one embodiment of the present application.

[0033] Description of reference numerals:

[0034] 1. Crystallization device; 2. Heat exchange medium production device; 3. Material storage tank; 4. Filter; 11. Crystallization tube; 20. Device body; 21. Circulation pump; 22. Partition; 23. Heat exchange coil; 24. Cold source; 31. Liquid transfer pump; 41. Shell; 42. Filter layer; 43. Funnel; 44. Vacuum pump; 101. Heat exchange medium inlet; 102. Heat exchange medium outlet; 111. Outer tube; 112. Inner tube; 2 01, overflow port; 202, medium outlet; 203, medium inlet; 401, discharge port; 402, air extraction port; 403, liquid inlet; 404, discharge port; 1101, material inlet; 1102, material outlet; 1111, straight outer tube; 1112, curved outer tube; 1121, straight inner tube; 1122, curved inner tube; 1123, spiral belt; 1201, inlet; 1202, outlet. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts also fall within the scope of protection of this application.

[0036] like Figure 1 As shown, the present application provides a cooling crystallization device for sodium sulfate production, comprising a crystallization device 1, wherein a crystallization tube 11 is provided in the crystallization device 1; both ends of the crystallization tube 11 extend out of the crystallization device 1;

[0037] The heat exchange medium input end of the crystallization tube 11 is connected to the circulation pump 21 and the heat exchange medium production device 2 in sequence; the material input end of the crystallization tube 11 is connected to the liquid transfer pump 31 and the material storage tank 3 in sequence;

[0038] The heat exchange medium output end of the crystallization tube 11 is connected to the input end of the heat exchange medium production device 2; the material output end of the crystallization tube 11 is connected to the filter 4 and the material storage tank 3 in sequence;

[0039] A heat exchange medium inlet 101 is provided at the lower portion of one side of the crystallization device 1, and a heat exchange medium outlet 102 is provided at the upper portion; the heat exchange medium inlet 101 is connected to the circulation pump 21 and the heat exchange medium production device 2 in sequence; the heat exchange medium outlet 102 is connected to the input end of the heat exchange medium production device 2.

[0040] A cooling crystallization device in sodium sulfate production, its working process is as follows:

[0041] During use, the liquid transfer pump 31 is used to transfer the supersaturated sodium sulfate solution (i.e., material) in the material storage tank 3 into the crystallization tube 11. When the supersaturated sodium sulfate solution flows out of the material output end of the crystallization tube 11 (the temperature is 35-40°C), the circulation pump 21 is turned on to pass the heat exchange medium (in this application, the chilled brine with a temperature of -10--5°C) in the heat exchange medium storage area of ​​the heat exchange medium production device 2 into the crystallization tube 11 and the crystallization device 1. (The supersaturated sodium sulfate solution is introduced first and then the heat exchange medium (i.e., chilled brine) is introduced to prevent the supersaturated sodium sulfate solution from cooling and rapidly crystallizing in the crystallization tube 11 to form crystals that clog the pipe. The supersaturated sodium sulfate solution generates crystals in the crystallization tube 11. Since the crystallization tube 11 is coiled and folded with multiple layers, it can ensure that the material is fully crystallized in the crystallization tube 11. The crystallized material is input into the filter 4 for solid-liquid separation, and the mother liquor obtained by filtration is returned to the material storage tank 3 for the next cycle of crystallization and separation; the filter cake obtained by filtration can be discharged through the filter 4 to the corresponding receiving device for subsequent processing.

[0042] The heat exchange medium in the crystallization device 1 and the crystallization tube 11 will be returned from the medium input end of the heat exchange medium production device 2, and after being regenerated (i.e., cooled to the required temperature again), it will be used for refrigeration in the next cycle.

[0043] The device of the present application is provided with a crystallization device 1, and a supersaturated sodium sulfate solution is passed into a crystallization tube 11. The low-temperature heat exchange medium supplied by the heat exchange medium production device 2 is used to crystallize the supersaturated sodium sulfate solution in the crystallization tube 11, and the material after crystallization is transferred to the filter 4 for solid-liquid separation. The mother liquor after separation is returned to the material storage tank 3 for the next round of crystallization, and the heat exchange medium after heat exchange is returned to the heat exchange medium production device 2 for regeneration. The device of the present application cools and crystallizes the supersaturated sodium sulfate solution through the coordinated use of the above-mentioned equipment, and uses the crystallization tube 11 to achieve continuous crystallization of the supersaturated sodium sulfate solution, thereby overcoming the disadvantages of the traditional intermittent crystallization method using a crystallization kettle, which has low crystallization efficiency and affects production efficiency.

[0044] Alternatively, as Figure 2 As shown, the crystallization tube 11 is coiled and folded in multiple layers, and the crystallization tube 11 includes an outer tube 111 and an inner tube 112 that are coaxially arranged;

[0045] The outer tube 111 includes a straight outer tube 1111 and a curved outer tube 1112 , and adjacent straight outer tubes 1111 are connected end to end through the curved outer tube 1112 ;

[0046] Both ends of the outer tube 111 are closed, and a material inlet 1101 and a material outlet 1102 are respectively opened on the tube wall at both ends. The material inlet 1101 is connected to the output end of the liquid transfer pump 31; the material outlet 1102 is connected to the material input end of the filter 4.

[0047] In the present application, the crystallization tube 11 is coiled and folded in multiple layers, and in this way, the length of the crystallization tube 11 can be extended within a limited space, thereby extending the crystallization time and ensuring that the material is fully crystallized in the crystallization tube 11.

[0048] In the present application, the connection method between the straight portion outer tube 1111 and the curved portion outer tube 1112 can be a flange connection, so as to facilitate maintenance, cleaning and replacement of the pipeline.

[0049] Alternatively, as Figure 2 As shown, the inner tube 112 includes a straight inner tube 1121 and a curved inner tube 1122 , and adjacent straight inner tubes 1121 are connected end to end through the curved inner tube 1122 ;

[0050] One end of the inner tube 112 is an inlet 1201 , and the other end is an outlet 1202 . The inlet 1201 is connected to the output end of the circulation pump 21 , and the outlet 1202 is connected to the heat exchange medium production device 2 .

[0051] In the present application, the same cooling medium as that outside the crystallization tube 11 flows in the inner tube 112, that is, the cooled material is sandwiched between two layers of cooling medium. This method can quickly cool the cooled material to increase the crystallization rate. The inner tube 112 can be fixed to the outer tube 111 by setting connecting ribs inside the connection between the straight outer tube 1111 and the curved outer tube 1112 of the outer tube 111 to fix the inner tube 112 inside the outer tube 111; or by setting a perforated disk inside the connection between the straight outer tube 1111 and the curved outer tube 1112 of the outer tube 111 to allow the inner tube 112 to pass through the perforated disk to achieve the fixation of the inner tube 112, and the perforated disk can also play the role of stirring the material flow.

[0052] Alternatively, as Figure 3 As shown, a spiral belt 1123 is wound around the outer periphery of the straight inner tube 1121 along the length direction of the straight inner tube 1121 .

[0053] In the present application, a spiral belt 1123 is provided on the outer periphery of the straight inner tube 1121. The impact of the liquid flow of the material flowing through the spiral belt 1123 and the guidance of the liquid flow by the spiral belt 1123 can be utilized to achieve the purpose of stirring the liquid flow and increasing the turbulence of the liquid flow, thereby avoiding the crystallization of the material to generate large and fast crystals to block the pipeline, and the occurrence of adverse consequences such as the crystals of the material adhering to the pipeline.

[0054] Alternatively, as Figure 4 As shown, the filter 4 includes a housing 41, and the interior of the housing 41 is divided into an upper liquid inlet area and a lower mother liquid area by a filter layer 42;

[0055] A funnel 43 is provided on the lower surface of the filter layer 42 for supporting the filter layer 42 and guiding the mother liquid;

[0056] A discharge port 401 is provided on one side wall of the liquid inlet area of ​​the housing 41 near the filter layer 42 ;

[0057] A liquid inlet 403 is provided at the top of the shell 41 and is connected to the material output end of the crystallization tube 11 ; a liquid discharge port 404 is provided at the bottom of the shell 41 and is connected to the material storage tank 3 .

[0058] In this application, filter 4 is used to separate the crystals from the mother liquor after crystallization. The input material containing crystals is filtered through filter layer 42 for solid-liquid separation. The filtered mother liquor falls into the mother liquor area through funnel 43 and is then returned to material storage tank 3 for the next cycle of crystallization and separation. The filter cake obtained by filtration can be discharged through discharge port 401 provided on the side of filter 4 to a corresponding receiving device for subsequent processing.

[0059] Alternatively, as Figure 5 As shown, a suction port 402 is provided on one side wall of the mother liquid region of the housing 41 near the filter layer 42 and is connected to a vacuum pump 44 .

[0060] In the present application, an air extraction port 402 connected to a vacuum pump 44 is provided on the housing 41 of the filter 4, and the mother liquid area can be vacuumed by the vacuum pump 44 to improve the filtering efficiency.

[0061] Alternatively, as Figure 6 As shown, the heat exchange medium production device 2 includes a device body 20, and the device body 20 is divided into a heat exchange medium storage area and a heat exchange medium production area by a partition 22;

[0062] The partition plate 22 is provided with an overflow port 201 for connecting the heat exchange medium storage area and the heat exchange medium production area;

[0063] A medium outlet 202 is provided on one side of the device body 20 where the heat exchange medium storage area is located, and is connected to the input end of the circulation pump 21;

[0064] A heat exchange coil 23 is provided in the device body 20 of the heat exchange medium production area, and the heat exchange coil 23 is connected in series with the cold source 24 to form a loop;

[0065] A medium inlet 203 connected to the heat exchange medium outlet 102 and the heat exchange medium output end of the crystallization tube 11 is provided at the lower portion of one side of the device body 20 in the heat exchange medium production area.

[0066] In the present application, the cold source 24 can be realized by vaporizing liquid ammonia, such as obtaining cold energy through an ammonia absorption process or obtaining cold energy through an ammonia compression process.

[0067] The heat exchange medium is chilled brine, and the temperature of the heat exchange medium generated after heat exchange with the cold source 24 is -5 to -10° C. In actual use, a heat insulation layer must be provided on the outside of the device body 20 to prevent the loss of cold and energy waste.

[0068] In actual use, the heat exchange medium returned from the medium inlet 203 of the heat exchange medium production device 2 to the heat exchange medium production area is regenerated through heat exchange and cooling with the refrigerant output by the cold source 24 in the heat exchange coil 23, and then flows into the heat exchange medium storage area through the overflow port 201 on the partition 22 for temporary storage and use in the next cycle of refrigeration.

[0069] A cooling crystallization device in sodium sulfate production, its working process is as follows:

[0070] During use, the liquid transfer pump 31 is used to input the supersaturated sodium sulfate solution (i.e., material) in the material storage tank 3 from the material inlet 1101 of the outer tube 111 in the crystallization tube 11 into the space between the outer tube 111 and the inner tube 112; when the supersaturated sodium sulfate solution flows out from the material outlet 1102 of the outer tube 111 (the temperature is 35-40°C), the circulation pump 21 is turned on to input the heat exchange medium (in this application, the frozen brine with a temperature of -10 to -5°C) in the heat exchange medium storage area of ​​the heat exchange medium production device 2 from the heat exchange medium inlet 1201 at one end of the inner tube 112 into the inner tube 112. The material flow direction and the heat exchange medium flow direction can be countercurrent or parallel, and countercurrent is preferred in actual use; at the same time, the heat exchange medium will also enter the crystallization device 1 from the heat exchange medium inlet 101 of the crystallization device 1 to cool the crystallization tube 11 as a whole. (The purpose of introducing a supersaturated sodium sulfate solution first and then a heat exchange medium (i.e., chilled brine) is to prevent the supersaturated sodium sulfate solution from rapidly crystallizing when cooled in the crystallization tube 11 and the resulting crystals from clogging the tube.) The supersaturated sodium sulfate solution generates crystals in the crystallization tube 11. Since a spiral belt 1123 is distributed on the periphery of the straight inner tube 1121, the flowing material is stirred when passing through the spiral belt 1123 due to the guiding and blocking effect of the spiral belt 1123, causing the material to form turbulent flow. This can, on the one hand, prevent the formation of large crystals that could clog the tube, and on the other hand, prevent the generated crystals from depositing on the inner wall of the outer tube 111 and the outer wall of the inner tube 112. Since the crystallization tube 11 is coiled and folded with multiple layers, it can ensure that the material is fully crystallized in the crystallization tube 11. The crystallized material is output through the material outlet 1102 into the filter 4.

[0071] In the filter 4, the input crystallization material is filtered through the filter layer 42, and at the same time, the vacuum pump 44 is used to evacuate the air from the exhaust port 402 to reduce the pressure, thereby accelerating the filtration process. The mother liquor obtained by filtration falls into the mother liquor area from the funnel 43, and is then returned to the material storage tank 3 for the next cycle of crystallization and separation; the filter cake obtained by filtration can be discharged to the corresponding receiving device through the discharge port 401 opened on the side of the filter 4 for subsequent processing.

[0072] The heat exchange medium in the crystallization device 1 and the heat exchange medium in the inner tube 112 will return to the heat exchange medium production area from the medium inlet 203 of the heat exchange medium production device 2, and will be regenerated by heat exchange and cooling with the refrigerant output by the cold source 24 in the heat exchange coil 23, and then flow into the heat exchange medium storage area through the overflow port 201 on the partition 22 for temporary storage and use in the next cycle of refrigeration.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cooling crystallization device in sodium sulfate production, characterized in that: It comprises a crystallization device (1), wherein a crystallization tube (11) is arranged in the crystallization device (1); both ends of the crystallization tube (11) extend out of the crystallization device (1); The heat exchange medium input end of the crystallization tube (11) is connected to the circulation pump (21) and the heat exchange medium production device (2) in sequence; the material input end of the crystallization tube (11) is connected to the liquid transfer pump (31) and the material storage tank (3) in sequence; The heat exchange medium output end of the crystallization tube (11) is connected to the input end of the heat exchange medium production device (2); the material output end of the crystallization tube (11) is connected to the filter (4) and the material storage tank (3) in sequence; A heat exchange medium inlet (101) is provided at the lower portion of one side of the crystallization device (1), and a heat exchange medium outlet (102) is provided at the upper portion; the heat exchange medium inlet (101) is connected to a circulation pump (21) and a heat exchange medium production device (2) in sequence; and the heat exchange medium outlet (102) is connected to an input end of the heat exchange medium production device (2).

2. The cooling crystallization device in the sodium sulfate production according to claim 1, characterized in that, The crystal tube (11) is coiled and folded in multiple layers, and the crystal tube (11) comprises an outer tube (111) and an inner tube (112) which are coaxially arranged; The outer tube (111) comprises a straight outer tube (1111) and a curved outer tube (1112), and adjacent straight outer tubes (1111) are connected end to end via the curved outer tube (1112); The outer tube (111) is closed at both ends, and a material inlet (1101) and a material outlet (1102) are respectively provided on the tube walls at both ends; the material inlet (1101) is connected to the output end of the liquid transfer pump (31); and the material outlet (1102) is connected to the material input end of the filter (4).

3. The cooling crystallization device in the sodium sulfate production according to claim 2, characterized in that, The inner tube (112) comprises a straight inner tube (1121) and a curved inner tube (1122), and adjacent straight inner tubes (1121) are connected end to end via the curved inner tube (1122); One end of the inner tube (112) is an inlet (1201), and the other end is an outlet (1202). The inlet (1201) is connected to the output end of the circulation pump (21), and the outlet (1202) is connected to the heat exchange medium production device (2).

4. The cooling crystallization device in the sodium sulfate production according to claim 3, characterized in that, A spiral belt (1123) is wound around the outer circumference of the straight inner tube (1121) along the length direction of the straight inner tube (1121).

5. The cooling crystallization device in the production of sodium sulfate according to claim 1, characterized in that, The filter (4) comprises a housing (41), wherein the housing (41) is divided into an upper liquid inlet area and a lower mother liquid area by a filter layer (42); A funnel (43) is provided on the lower surface of the filter layer (42) for supporting the filter layer (42) and guiding the mother liquid; A discharge port (401) is provided on one side wall of the liquid inlet area of ​​the shell (41) near the filter layer (42); The top of the shell (41) is provided with a liquid inlet (403) which is connected to the material output end of the crystallization tube (11); the bottom of the shell (41) is provided with a liquid discharge port (404) which is connected to the material storage tank (3).

6. The cooling crystallization device in the production of sodium sulfate according to claim 5, characterized in that A suction port (402) is provided on one side wall of the mother liquid region of the shell (41) near the filtering layer (42) and is connected to a vacuum pump (44).

7. The cooling crystallization device in the sodium sulfate production according to any one of claims 1 to 6, characterized in that: The heat exchange medium production device (2) comprises a device body (20), wherein the device body (20) is divided into a heat exchange medium storage area and a heat exchange medium production area by a partition (22); The partition plate (22) is provided with an overflow port (201) for connecting the heat exchange medium storage area and the heat exchange medium production area; A medium outlet (202) is provided on one side of the device body (20) where the heat exchange medium storage area is located, and is connected to the input end of the circulation pump (21); A heat exchange coil (23) is arranged in the device body (20) of the heat exchange medium production area, and the heat exchange coil (23) is connected in series with the cold source (24) to form a loop; A medium inlet (203) connected to the heat exchange medium outlet (102) and the heat exchange medium output end of the crystallization tube (11) is provided at the lower part of one side of the device body (20) of the heat exchange medium production area.

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