System for recovering potassium perchlorate and sodium chloride from wastewater
By constructing a continuous recovery system and utilizing multiple devices for evaporation concentration, graded centrifugation, and purification, the problem of insufficient recovery of potassium perchlorate and sodium chloride has been solved, achieving efficient resource recovery and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEBEI LEHENG CHEM EQUIP MFG
- Filing Date
- 2025-07-21
- Publication Date
- 2026-07-14
AI Technical Summary
Existing potassium perchlorate production processes generate large amounts of saline wastewater, making it difficult to efficiently recover potassium perchlorate and sodium chloride, resulting in resource waste and environmental pollution.
A continuous recovery system was constructed using devices such as MVR evaporation crystallization, MVR centrifugation, cooling crystallization, cooling centrifugation, back dissolution, freeze crystallization, and freeze centrifugation. Potassium perchlorate and sodium chloride were gradually separated and purified through operations such as evaporation concentration, fractional centrifugation, cooling crystallization, back dissolution purification, and freeze crystallization.
It achieves efficient and high-quality recovery of potassium perchlorate and sodium chloride from wastewater, improving resource utilization and reducing environmental pollution.
Smart Images
Figure CN224493953U_ABST
Abstract
Description
Technical Field
[0001] The embodiments of this utility model relate to the field of wastewater recycling technology, specifically to a system for recycling potassium perchlorate and sodium chloride from wastewater. Background Technology
[0002] Potassium perchlorate is a stable oxidant widely used in the manufacture of explosives, fireworks, firecrackers, and household ignition coal. The potassium chloride metathesis process is an important method for producing potassium perchlorate. The traditional process involves electrolyzing sodium chlorate to form sodium perchlorate, which then undergoes a metathesis reaction with potassium chloride, followed by cooling and centrifugation to obtain potassium perchlorate. Existing potassium perchlorate production processes generate large amounts of saline wastewater, which often contains potassium perchlorate and sodium chloride. Direct discharge of this wastewater is problematic because potassium perchlorate has oxidizing and toxic properties, and sodium chloride alters the ion balance in water bodies. Both can damage aquatic ecosystems, impacting aquatic life and potentially seeping into the soil, polluting the environment and jeopardizing ecological security. Furthermore, these valuable components are wasted, contradicting the concept of sustainable resource utilization. However, existing recycling processes suffer from incomplete procedures and missing separation and purification steps, hindering efficient recovery and resulting in both resource waste and environmental pollution risks. Therefore, developing a system that effectively recovers potassium perchlorate and sodium chloride from wastewater, reducing environmental pollution and enabling resource reuse is of urgent practical significance. Utility Model Content
[0003] To overcome the above-mentioned defects, the embodiments of this utility model provide a system for recovering potassium perchlorate and sodium chloride from wastewater, which solves the technical problem of insufficient recovery of potassium perchlorate and sodium chloride from wastewater in the prior art.
[0004] According to one aspect, at least one embodiment of the present invention provides a system for recovering potassium perchlorate and sodium chloride from wastewater, comprising, in sequence, an MVR evaporation crystallization device, an MVR centrifuge device, a cooling crystallization device, a cooling centrifuge device, a reverse dissolution device, a reverse dissolution centrifuge device, a freeze crystallization device, and a freeze centrifuge device. The MVR evaporation crystallization device is used to evaporate and concentrate the wastewater to obtain a sodium chloride-containing crystal concentrate. The MVR centrifuge device is connected to the MVR evaporation crystallization device and is used to receive the sodium chloride-containing crystal concentrate and centrifuge it to obtain sodium chloride crystals and a first mother liquor. The cooling crystallization device is connected to the MVR centrifuge device and is used to receive the first mother liquor and perform cooling crystallization to obtain... A solution containing crude potassium perchlorate crystals is obtained. The cooling centrifuge device is connected to the cooling crystallization device to receive the solution containing crude potassium perchlorate crystals and centrifuge it to obtain crude potassium perchlorate and a second mother liquor. The crude potassium perchlorate crystals are then introduced into the reverse dissolution device for reverse dissolution to obtain a third mother liquor. The reverse dissolution centrifuge device is connected to the reverse dissolution device to receive the third mother liquor and centrifuge it to obtain refined potassium perchlorate and a fourth mother liquor. The freezing crystallization device is connected to the reverse dissolution centrifuge device to receive and freeze the fourth mother liquor to obtain a solution containing refined potassium perchlorate. The freezing centrifuge device is connected to the freezing crystallization device to receive the fourth mother liquor and centrifuge it to obtain refined potassium perchlorate and a fifth mother liquor.
[0005] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided in at least one embodiment of the present invention, a system preheating device is also included. The system preheating device is used to preheat the wastewater. The system preheating device includes a feed pump, a condensate preheater, and a non-condensable gas preheater connected in sequence. The non-condensable gas preheater is connected to the MVR evaporation crystallization device.
[0006] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of the present invention, the MVR evaporation crystallization device includes a crystallization separator, a forced circulation pump, a forced circulation evaporator, and a condensate tank connected in sequence. The crystallization separator is connected to a centrifugal steam compressor, and a sodium chloride-containing crystal concentrate is obtained after separation by the crystallization separator.
[0007] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided in at least one embodiment of this utility model, a folding demister is connected between the crystallizer and the centrifugal steam compressor.
[0008] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of this utility model, the MVR evaporation crystallization device and the MVR centrifuge device are connected by an MVR discharge pump. The MVR discharge pump transfers the sodium chloride crystal concentrate from the MVR evaporation crystallization device to the MVR centrifuge device. The MVR centrifuge device includes a hydrocyclone, an MVR centrifuge, an MVR mother liquor tank, and an MVR mother liquor pump connected in sequence. The hydrocyclone is used to classify the sodium chloride crystals, and the MVR centrifuge obtains sodium chloride crystals and the first mother liquor after centrifugation.
[0009] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of this utility model, the cooling crystallization device includes a cooling crystallizer and a cooling discharge pump connected in sequence. The cooling crystallizer is used to receive the first mother liquor. After the first mother liquor is treated by the cooling crystallizer, crude potassium perchlorate is precipitated and a solution containing crude potassium perchlorate crystals is obtained. The cooling centrifugation device includes a cooling centrifuge, a cooling mother liquor tank, and a cooling mother liquor pump connected in sequence. The cooling centrifuge is used to receive the solution containing crude potassium perchlorate crystals and centrifuge to obtain crude potassium perchlorate and the second mother liquor. The second mother liquor enters the cooling mother liquor tank and is then pumped into the reverse dissolution device by the cooling mother liquor pump.
[0010] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of the present invention, the reverse dissolution device includes a reverse dissolution tank and a reverse dissolution pump connected in sequence, and the crude potassium perchlorate crystals are dissolved in the reverse dissolution tank to obtain the third mother liquor;
[0011] The reverse dissolution centrifugation device includes a reverse dissolution centrifuge, a reverse dissolution mother liquor tank, and a reverse dissolution mother liquor pump connected in sequence. The reverse dissolution pump is used to input the third mother liquor in the reverse dissolution tank into the reverse dissolution centrifuge. After centrifugation by the reverse dissolution centrifuge, refined potassium perchlorate and the fourth mother liquor are obtained. The fourth mother liquor enters the reverse dissolution mother liquor tank and is then pumped into the freeze crystallization device via the reverse dissolution mother liquor pump.
[0012] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of the present invention, the cryogenic crystallization device includes a cryogenic crystallizer and a cryogenic discharge pump connected in sequence. The cryogenic crystallizer is connected to a refrigeration unit and a refrigerant water tank. After the fourth mother liquor enters the cryogenic crystallizer for cryogenic crystallization treatment, the solution containing high-quality potassium perchlorate is precipitated and then fed into the cryogenic centrifuge device through the cryogenic discharge pump.
[0013] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of the present invention, the refrigerated centrifugation device includes a refrigerated centrifuge, a refrigerated mother liquor tank, and a refrigerated mother liquor pump connected in sequence. The refrigerated centrifuge is used to receive the solution containing refined potassium perchlorate, and after centrifugation, refined potassium perchlorate and a fifth mother liquor are obtained. The fifth mother liquor enters the refrigerated mother liquor tank, and the refrigerated mother liquor pump is used to pump the refrigerated mother liquor into the MVR evaporation crystallization device.
[0014] For example, in a system for recovering potassium perchlorate and sodium chloride from wastewater provided by at least one embodiment of this utility model, the second mother liquor and the fifth mother liquor are recycled to the MVR evaporation and crystallization device.
[0015] The beneficial effects of the embodiments of this utility model are as follows:
[0016] This invention constructs a coherent recovery system by sequentially setting up an MVR evaporation crystallization device, an MVR centrifugation device, a cooling crystallization device, a cooling centrifugation device, a reverse dissolution device, a reverse dissolution centrifugation device, a freeze crystallization device, and a freeze centrifugation device. By progressively performing operations such as evaporation concentration, graded centrifugation, cooling crystallization, reverse dissolution purification, and freeze crystallization on wastewater, it can specifically separate sodium chloride crystals and mother liquor at different stages. Through multi-stage purification treatment, it effectively improves the recovery quality of potassium perchlorate and sodium chloride, solves the problem of low-quality recovered products in existing technologies, and achieves efficient and high-quality recovery and utilization of valuable components in wastewater. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this utility model and these drawings without any creative effort.
[0018] Figure 1 This is a schematic diagram of a system for recovering potassium perchlorate and sodium chloride from wastewater according to one embodiment of the present invention;
[0019] Figure 2 This is a flowchart of a system for recovering potassium perchlorate and sodium chloride from wastewater in one embodiment of the present invention;
[0020] In the diagram: 1. Feed pump; 2. Condensate preheater; 3. Non-condensable gas preheater; 4. Crystallizer separator; 5. Forced circulation pump; 6. Forced circulation evaporator; 7. Condensate tank; 8. Demister; 9. Centrifugal steam compressor; 10. MVR discharge pump; 11. Hydrocyclone; 12. MVR centrifuge; 13. MVR mother liquor tank; 14. MVR mother liquor pump; 15. Cooling crystallizer; 16. Cooling discharge pump; 17. Cooling centrifuge; 18. Cooling mother liquor tank; 19. Cooling mother liquor pump; 20. Reverse dissolution tank; 21. Reverse dissolution pump; 22. Reverse dissolution centrifuge; 23. Reverse dissolution mother liquor tank; 24. Reverse dissolution mother liquor pump; 25. Refrigerated crystallizer; 26. Refrigerated discharge pump; 27. Refrigerated centrifuge; 28. Refrigerated mother liquor tank; 29. Refrigerated mother liquor pump; 30. Refrigeration unit; 31. Refrigerant water tank. Detailed Implementation
[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit its scope.
[0022] To keep the drawings concise, each drawing only schematically shows the parts relevant to the disclosure; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."
[0023] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0025] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0026] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0027] like Figure 1 and Figure 2 As shown, it illustrates a system for recovering potassium perchlorate and sodium chloride from wastewater in one embodiment of the present invention.
[0028] In some examples, the wastewater to be treated enters an MVR evaporation crystallization unit, which performs evaporation and concentration operations on the wastewater. During the evaporation process, as water continues to evaporate, the sodium chloride concentration in the wastewater system gradually increases to a supersaturated state, thereby precipitating sodium chloride crystals and forming a concentrated solution containing sodium chloride crystals. The MVR evaporation crystallization unit utilizes the evaporation process to achieve the initial separation of sodium chloride from other components.
[0029] The MVR centrifuge unit is connected to the MVR evaporation crystallization unit. The sodium chloride crystal concentrate enters the MVR centrifuge unit from the MVR evaporation crystallization unit. The MVR centrifuge unit performs centrifugal separation treatment on the sodium chloride crystal concentrate. Under the action of centrifugal force, sodium chloride crystals are separated from the mother liquor, obtaining sodium chloride crystals and a first mother liquor. The first mother liquor is the residual liquid after the separation of sodium chloride crystals, which improves the recovery efficiency of sodium chloride. Moreover, the separated first mother liquor can be used as a raw material for potassium perchlorate recovery, realizing the cascade utilization of resources.
[0030] The cooling crystallization device is connected to the MVR centrifuge, and the first mother liquor is transported to the cooling crystallization device by the MVR centrifuge. The cooling crystallization device cools the first mother liquor, lowering its temperature. Since the solubility of potassium perchlorate decreases significantly with decreasing temperature, the potassium perchlorate in the first mother liquor reaches a supersaturated state and precipitates crude potassium perchlorate crystals, providing crude raw material for potassium perchlorate recovery and forming a solution containing crude potassium perchlorate crystals.
[0031] The cooling centrifuge device is connected to the cooling crystallization device. The solution containing crude potassium perchlorate crystals enters the cooling centrifuge device. The cooling centrifuge device separates the crude potassium perchlorate crystals from the liquid through centrifugation, yielding crude potassium perchlorate and a second mother liquor. The second mother liquor is the remaining liquid after the crude potassium perchlorate has been separated, reducing the amount of potassium perchlorate remaining in the first mother liquor. The second mother liquor can then be used in subsequent processing steps, avoiding waste of potassium perchlorate.
[0032] Crude potassium perchlorate crystals are fed to a reverse dissolution unit, where they dissolve to form a third mother liquor. This process removes some impurities from the crude product. A reverse dissolution centrifuge unit is connected to the reverse dissolution unit, and the third mother liquor enters the reverse dissolution centrifuge unit from there. The reverse dissolution centrifuge unit separates the third mother liquor by centrifugation, yielding refined potassium perchlorate and a fourth mother liquor. The fourth mother liquor is the remaining liquid after the refined potassium perchlorate has been separated. The reverse dissolution centrifuge unit significantly improves product purity, meeting higher application requirements. Simultaneously, the fourth mother liquor can be further processed in a freeze crystallization unit, increasing the overall recovery rate of potassium perchlorate.
[0033] The cryo-crystallization unit is connected to the reverse dissolution centrifuge unit, and the fourth mother liquor enters the cryo-crystallization unit. The cryo-crystallization unit freezes the fourth mother liquor, utilizing the significant decrease in potassium perchlorate solubility at low temperatures. By lowering the temperature of the fourth mother liquor, the remaining potassium perchlorate is further precipitated, achieving the recovery of potassium perchlorate from the fourth mother liquor and forming a solution containing high-quality potassium perchlorate. The cryo-centrifuge unit is connected to the cryo-crystallization unit, and the solution containing high-quality potassium perchlorate enters the cryo-centrifuge unit. The cryo-centrifuge unit centrifuges the solution containing high-quality potassium perchlorate, obtaining high-quality potassium perchlorate and a fifth mother liquor. The fifth mother liquor is the residual liquid after the high-quality potassium perchlorate has been separated. The fifth mother liquor can be recycled, reducing the loss of valuable components.
[0034] The entire system, through the sequential connection and synergistic action of an MVR evaporation crystallization unit, an MVR centrifuge unit, a cooling crystallization unit, a cooling centrifuge unit, a reverse dissolution unit, a reverse dissolution centrifuge unit, a freeze crystallization unit, and a freeze centrifuge unit, forms a complete potassium perchlorate and sodium chloride recovery process. This process first separates and recovers sodium chloride, then gradually separates and purifies potassium perchlorate, achieving effective separation and recovery of the two substances. It solves the problem of insufficient recovery of potassium perchlorate and sodium chloride from wastewater in existing technologies, improves resource recovery efficiency, and reduces environmental pollution from wastewater discharge.
[0035] The specific recovery process for potassium perchlorate and sodium chloride in this embodiment is as follows: Wastewater is preheated before entering the system. Feed pump 1 delivers wastewater to condensate preheater 2, where it exchanges heat with the condensate produced by the MVR evaporation crystallization device to achieve initial temperature increase. Subsequently, the wastewater enters non-condensable gas preheater 3, where it exchanges heat again with the non-condensable gas discharged from the MVR evaporation crystallization device, further increasing its temperature before entering the MVR evaporation crystallization device. Preheated wastewater enters crystallizer 4. Forced circulation pump 5 transports the liquid to forced circulation evaporator 6 for heating and evaporation. The generated secondary steam enters the upper part of crystallizer 4, and after being demisted by folded demister 8, it is compressed and heated by centrifugal steam compressor 9 and returned to forced circulation evaporator 6 as a heat source. The condensate is collected in condensate tank 7. The liquid continues to evaporate in crystallizer 4. When the sodium chloride concentration reaches supersaturation, crystals precipitate, forming a concentrated sodium chloride crystal solution. The circulation structure of crystallizer 4 and forced circulation evaporator 6 ensures uniform heating of the liquid and avoids local crystallization blockage. Centrifugal steam compressor 9 realizes the recycling of secondary steam, significantly reducing energy consumption. Folded demister 8 effectively purifies the steam, preventing impurities from entering the compressor and causing wear, while improving the purity of subsequent crystallized products. The three work synergistically to improve the stability and efficiency of the MVR evaporation crystallization device. The concentrated sodium chloride crystal solution is fed into hydrocyclone 11 via MVR discharge pump 10. Centrifugal force fractionation enriches the sodium chloride crystals, which then enter MVR centrifuge 12 to separate sodium chloride crystals and the first mother liquor. The first mother liquor is temporarily stored in MVR mother liquor tank 13 and then pumped to the cooling crystallization unit by MVR mother liquor pump 14. The fractionation process in hydrocyclone 11 increases the concentration of sodium chloride crystals and reduces the processing load on MVR centrifuge 12. The efficient separation in MVR centrifuge 12 ensures complete separation of sodium chloride crystals and the first mother liquor, providing pure raw materials for subsequent potassium perchlorate recovery. This two-stage treatment improves the efficiency and purity of sodium chloride recovery. The first mother liquor enters cooling crystallizer 15, where cooling treatment precipitates potassium perchlorate. The resulting solution containing crude potassium perchlorate crystals is fed into cooling centrifuge 17 via cooling discharge pump 16, separating crude potassium perchlorate and the second mother liquor. The second mother liquor is temporarily stored in cooling mother liquor tank 18 and then pumped to the reverse dissolution unit by cooling mother liquor pump 19. The cooling crystallizer 15 precisely controls the precipitation conditions of potassium perchlorate through temperature regulation, while the cooling centrifuge 17 rapidly separates the crude potassium perchlorate from the second mother liquor. The two work together to achieve the initial purification of potassium perchlorate. The continuous supply of the second mother liquor provides raw materials for subsequent processing, avoiding material retention in intermediate stages.Crude potassium perchlorate is dissolved in a back-dissolving tank 20 to form a third mother liquor, which is then pumped by a back-dissolving pump 21 to a back-dissolving centrifuge 22 to separate refined potassium perchlorate and a fourth mother liquor. The fourth mother liquor is temporarily stored in a back-dissolving mother liquor tank 23 and then pumped by a back-dissolving mother liquor pump 24 to a cryogenic crystallization unit. The back-dissolving tank 20 removes soluble impurities from the crude product through a dissolution-recrystallization principle, and the back-dissolving centrifuge 22 further separates and purifies the product, significantly improving the purity of the potassium perchlorate. This step, as a key purification step, effectively compensates for the insufficient purity obtained from cooling crystallization, ensuring the production of a high-quality product. The fourth mother liquor enters the cryogenic crystallizer 25, where it is cryogenically frozen under the synergistic action of the refrigeration unit 30 and the chilled water tank 31, causing the remaining potassium perchlorate to precipitate out. The resulting solution containing high-quality potassium perchlorate is sent to the refrigerated centrifuge 27 by the cryogenic discharge pump 26, where high-quality potassium perchlorate and the fifth mother liquor are separated. The fifth mother liquor is temporarily stored in the cryogenic mother liquor tank 28 and then transported to the MVR evaporation crystallization device by the cryogenic mother liquor pump 29.
[0036] The cryogenic crystallizer 25 utilizes a low-temperature environment to enhance potassium perchlorate precipitation, while the refrigeration unit 30 and chilled water tank 31 ensure stable low-temperature conditions. The refrigerated centrifuge 27 achieves efficient recovery of trace amounts of potassium perchlorate. The combination of these two components significantly improves the overall recovery rate of potassium perchlorate and provides qualified materials for mother liquor circulation. The second mother liquor pumped by the cooling mother liquor pump 19 and the fifth mother liquor pumped by the cryogenic mother liquor pump 29 are jointly returned to the MVR evaporation crystallization unit for recycling. The mother liquor reflux forms a closed-loop system, allowing for the secondary recovery of residual potassium perchlorate and sodium chloride, reducing resource waste; at the same time, it reduces the amount of waste liquid discharged from the system, lowering the risk of environmental pollution, and achieving a dual optimization of environmental protection and resource utilization.
[0037] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model 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 solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.
Claims
1. A system for recovering potassium perchlorate and sodium chloride from wastewater, characterized in that, The system comprises, in sequence, an MVR evaporation crystallization unit, an MVR centrifuge unit, a cooling crystallization unit, a cooling centrifuge unit, a reverse dissolution unit, a reverse dissolution centrifuge unit, a freeze crystallization unit, and a freeze centrifuge unit. The MVR evaporation crystallization unit is used to evaporate and concentrate wastewater to obtain a concentrated solution containing sodium chloride crystals. The MVR centrifuge unit is connected to the MVR evaporation crystallization unit and is used to receive the concentrated solution containing sodium chloride crystals and centrifuge it to obtain sodium chloride crystals and a first mother liquor. The cooling crystallization unit is connected to the MVR centrifuge unit and is used to receive the first mother liquor and perform cooling crystallization to obtain a solution containing crude potassium perchlorate crystals. The cooling centrifuge unit… The device is connected to the cooling crystallization apparatus to receive a solution containing crude potassium perchlorate crystals and centrifuge it to obtain crude potassium perchlorate and a second mother liquor. The crude potassium perchlorate crystals are then introduced into the reverse dissolution apparatus for reverse dissolution to obtain a third mother liquor. The reverse dissolution centrifuge apparatus is connected to the reverse dissolution apparatus to receive the third mother liquor and centrifuge it to obtain refined potassium perchlorate and a fourth mother liquor. The freezing crystallization apparatus is connected to the reverse dissolution centrifuge apparatus to receive and freeze the fourth mother liquor to obtain a solution containing refined potassium perchlorate. The freezing centrifuge apparatus is connected to the freezing crystallization apparatus to receive the fourth mother liquor and centrifuge it to obtain refined potassium perchlorate and a fifth mother liquor.
2. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, It also includes a system preheating device for preheating wastewater. The system preheating device includes a feed pump (1), a condensate preheater (2) and a non-condensable gas preheater (3) connected in sequence. The non-condensable gas preheater (3) is connected to the MVR evaporation crystallization device.
3. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The MVR evaporation crystallization device includes a crystallization separator (4), a forced circulation pump (5), a forced circulation evaporator (6), and a condensate tank (7) connected in sequence. The crystallization separator (4) is connected to a centrifugal steam compressor (9). After separation by the crystallization separator (4), a sodium chloride-containing crystal concentrate is obtained.
4. In the system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 3, a folding demister (8) is connected between the crystallizer (4) and the centrifugal steam compressor (9).
5. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The MVR evaporation crystallization device and the MVR centrifuge device are connected by an MVR discharge pump (10). The MVR discharge pump (10) transfers the sodium chloride crystal concentrate from the MVR evaporation crystallization device to the MVR centrifuge device. The MVR centrifuge device includes a hydrocyclone (11), an MVR centrifuge (12), an MVR mother liquor tank (13), and an MVR mother liquor pump (14) connected in sequence. The hydrocyclone (11) is used to classify the sodium chloride crystals. The MVR centrifuge (12) centrifuges to obtain sodium chloride crystals and the first mother liquor.
6. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The cooling crystallization device includes a cooling crystallizer (15) and a cooling discharge pump (16) connected in sequence. The cooling crystallizer (15) is used to receive the first mother liquor. After the first mother liquor is processed by the cooling crystallizer (15), the crude potassium perchlorate is precipitated and a solution containing crude potassium perchlorate crystals is obtained. The cooling centrifugation device includes a cooling centrifuge (17), a cooling mother liquor tank (18), and a cooling mother liquor pump (19) connected in sequence. The cooling centrifuge (17) is used to receive the solution containing crude potassium perchlorate crystals and centrifuge to obtain crude potassium perchlorate and the second mother liquor. The second mother liquor enters the cooling mother liquor tank (18) and enters the anti-dissolution device through the cooling mother liquor pump (19).
7. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The reverse dissolution device includes a reverse dissolution tank (20) and a reverse dissolution pump (21) connected in sequence. The crude potassium perchlorate crystals enter the reverse dissolution tank (20) and dissolve to obtain the third mother liquor. The reverse dissolution centrifugation device includes a reverse dissolution centrifuge (22), a reverse dissolution mother liquor tank (23), and a reverse dissolution mother liquor pump (24) connected in sequence. The reverse dissolution pump (21) is used to input the third mother liquor in the reverse dissolution tank (20) into the reverse dissolution centrifuge (22). After centrifugation by the reverse dissolution centrifuge (22), high-quality potassium perchlorate and the fourth mother liquor are obtained. The fourth mother liquor enters the reverse dissolution mother liquor tank (23) and enters the freeze crystallization device through the reverse dissolution mother liquor pump (24).
8. The system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The cryo-crystallization device includes a cryo-crystallizer (25) and a cryo-discharge pump (26) connected in sequence. The cryo-crystallizer (25) is connected to a refrigeration unit (30) and a chilled water tank (31). After the fourth mother liquor enters the cryo-crystallizer (25) for cryo-crystallization, the solution containing high-quality potassium perchlorate is precipitated and fed into the cryo-centrifuge device through the cryo-discharge pump (26).
9. A system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The refrigerated centrifuge device includes a refrigerated centrifuge (27), a refrigerated mother liquor tank (28), and a refrigerated mother liquor pump (29) connected in sequence. The refrigerated centrifuge (27) is used to receive the solution containing refined potassium perchlorate, and after centrifugation, refined potassium perchlorate and a fifth mother liquor are obtained. The fifth mother liquor enters the refrigerated mother liquor tank (28), and the refrigerated mother liquor pump (29) is used to pump the refrigerated mother liquor into the MVR evaporation crystallization device.
10. A system for recovering potassium perchlorate and sodium chloride from wastewater according to claim 1, characterized in that, The second mother liquor and the fifth mother liquor are recycled back to the MVR evaporation and crystallization device.