Inorganic salt mother liquor recycling system based on MVR evaporative crystallization

Abstract

The invention relates to the technical field of inorganic salt mother liquor treatment, in particular to an inorganic salt mother liquor recycling system based on MVR evaporative crystallization, which comprises three groups of sedimentation tanks and separation cylinders fixedly communicated with the bottoms of the sedimentation tanks, stirring components and sealing conical seats are arranged in the separation cylinders, and the tops of the sedimentation tanks are connected with liquid storage hoppers through liquid inlet pipes. An electromagnetic control valve is arranged on the liquid inlet pipe, and a calcium hydroxide solution, a sodium carbonate solution and a barium chloride solution are sequentially arranged in the multiple liquid storage hoppers from left to right; through staged treatment of the three groups of sedimentation tanks, the ion selective electrode sensor and the controller are combined to precisely add corresponding agents, the hetero ions are removed step by step in a targeted manner, and the subsequent progressive deep purification treatment is matched, so that a high-quality water quality basis is provided for efficient recycling of the mother liquor; and the problems of crystal quality reduction, equipment scaling and the like caused by hetero-ion enrichment are effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of inorganic salt mother liquor treatment technology, and in particular to an inorganic salt mother liquor recycling system based on MVR evaporation crystallization. Background Technology

[0002] Inorganic salt mother liquor is a byproduct remaining after separating the main salt crystals from high-salinity wastewater from industries such as chemical, metallurgical, salt lake chemical, and coal chemical industries using MVR evaporation crystallization technology. This mother liquor has significant inherent drawbacks: its composition is complex (containing Ca²⁺, Mg²⁺, ... It contains impurities, has high viscosity and high boiling point, and these impurities and heavy metals are easily enriched. If discharged directly, it will not only waste salt resources, but also cause environmental problems such as soil salinization and water pollution, which does not meet the requirements of the zero discharge policy for industrial wastewater.

[0003] In existing MVR inorganic salt mother liquor treatment technologies, no graded reuse pathways are designed to address the differences in impurity ion concentrations in the mother liquor, regardless of whether the impurities (Ca²⁺, Mg²⁺, ... Regardless of the concentration of impurities (such as ions), the mother liquor is directly returned to the MVR evaporation system or pretreatment front end via a single path, resulting in the inability to effectively divert impurities and their continuous accumulation. As the number of cycles increases, the concentration of impurities in the mother liquor increases exponentially: on the one hand, it significantly increases the viscosity and boiling point elevation of the mother liquor, forcing the MVR compressor to maintain a higher compression ratio, directly exacerbating the energy consumption per ton of water evaporated; on the other hand, the accumulated impurities easily form a hard scale layer on the heat exchange tubes of the evaporator and the inner wall of the crystallizer, causing severe under-deposit corrosion. This not only reduces heat exchange efficiency and further increases energy consumption, but also aggravates equipment wear, leading to frequent system shutdowns for cleaning and maintenance, seriously damaging operational stability, increasing maintenance costs and equipment lifespan, and ultimately resulting in a general decrease in the mother liquor recycling rate, making it difficult to achieve the zero-emission target.

[0004] To address the aforementioned technical deficiencies, a solution is proposed that utilizes a three-stage sedimentation tank system, combined with ion-selective electrode sensors and controllers to precisely add appropriate reagents, targeting and removing impurity ions step by step. This, coupled with subsequent progressive deep purification treatment, provides a high-quality water foundation for the efficient recycling of mother liquor, effectively preventing problems such as decreased crystal quality and equipment scaling caused by the accumulation of impurity ions. Summary of the Invention

[0005] The purpose of this invention is to provide an inorganic salt mother liquor recycling system based on MVR evaporation and crystallization to solve the aforementioned technical defects.

[0006] The objective of this invention can be achieved through the following technical solution: an inorganic salt mother liquor recycling system based on MVR evaporation crystallization, comprising three sets of sedimentation tanks and a separation cylinder fixedly connected to the bottom of each sedimentation tank, wherein the separation cylinder is equipped with a stirring assembly and a sealing cone seat, the top of each sedimentation tank is connected to a storage hopper through an inlet pipe, and an electromagnetic control valve is provided on the inlet pipe, wherein calcium hydroxide solution, sodium carbonate solution and barium chloride solution are arranged sequentially from left to right inside the multiple storage hoppers; The bottom of the separation cylinder is fixedly connected to a drain pipe, and a peristaltic pump is connected to each drain pipe. The free ends of the left drain pipe and the middle drain pipe are fixedly connected to the middle sedimentation tank and the right sedimentation tank, respectively. From left to right, a sand filter tank, an activated carbon adsorption tank, and an ion exchange resin tank are arranged on the right drain pipe.

[0007] Preferably, the bottom of the separation cylinder has a through-hole for discharging impurities that is slidably connected to the sealing cone seat, and a filter cover is fixedly connected to the bottom of the separation cylinder outside the discharge port. A plugging seat for blocking the liquid inlet of the drain pipe is slidably connected between the outer wall of the filter cover and the inner wall of the separation cylinder.

[0008] Preferably, a U-shaped frame is fixedly connected to the bottom of the separation cylinder, and a rotating shaft is rotatably connected between the U-shaped frame and the top of the sedimentation tank. A motor for driving the rotating shaft is installed on the U-shaped frame by bolts. Multiple stirring racks are fixedly connected to the rotating shaft inside the sedimentation tank, and multiple fixing racks are fixedly connected to the rotating shaft inside the filter cover.

[0009] Preferably, a brush plate is slidably connected to the fixed frame, and the bottom of the brush plate is in movable contact with the top of the sealing cone seat. An ear block is fixedly connected to the brush plate, and a spring is fixedly connected between the top and bottom sides of the ear block and the fixed frame.

[0010] Preferably, a rotating column is fixedly connected to the rotating shaft and movably connected to the sealing cone seat. An upper ring groove and a lower ring groove are provided on the annular outer wall of the rotating column. Two sets of spiral grooves are provided between the upper ring groove and the lower ring groove. Triangular communication ports connected to the upper ring groove and the lower ring groove are provided at both ends of the spiral groove. Two sets of guide pins that are adapted to the corresponding spiral grooves are fixedly connected to the inner wall of the sealing cone seat.

[0011] Preferably, the sealing cone seat has a limiting plate fixedly connected to both sides and slidably connected to the U-shaped frame, and a turntable is rotatably connected to the bottom of the sealing cone seat, and a spring is fixedly connected to the bottom of the turntable.

[0012] Preferably, guide wheels are fixedly connected to the bottom of the separation cylinder and the outer wall of the U-shaped frame, and the guide wheels are connected by a connecting rope. A vertical rod that extends movably through to the outside of the bottom of the separation cylinder is fixedly connected to the bottom of the liquid blocking seat, and the end of the vertical rod and the limiting plate are fixedly connected to the connecting rope. A rubber elastic layer is fixedly connected to the bottom of the liquid blocking seat.

[0013] Preferably, a collection tray is fixedly connected to the top of the U-shaped frame, a rotating plate is provided inside the collection tray, and multiple elastic scrapers are fixedly connected to the annular outer wall of the rotating plate. The rotating plate is fixedly installed to the rotating shaft through a one-way bearing, and a discharge hopper is installed on one side of the collection tray.

[0014] Preferably, the precipitation tank is provided with a control component, which includes an ion-selective electrode sensor embedded in the inner wall of the precipitation tank and a controller electrically connected to the ion-selective electrode sensor.

[0015] The beneficial effects of this invention are as follows: (1) This invention uses three sets of sedimentation tanks for graded treatment. Combined with corresponding ion selective electrode sensors, the concentrations of magnesium ions, calcium ions, and sulfate ions in the mother liquor are monitored in real time. The dosage of calcium hydroxide, sodium carbonate, and barium chloride solutions in the corresponding storage tanks is precisely controlled by the controller to achieve targeted and stepwise removal of impurities, avoiding waste of reagents or excessive introduction of new impurities. The subsequent progressive deep purification of sand filter tank, activated carbon adsorption tank and ion exchange resin tank can further intercept suspended solids, residual barium ions and trace amounts of calcium and magnesium ions, so that the concentration of impurities in the treated mother liquor is reduced to the range suitable for MVR evaporation and crystallization. This provides a high-quality water quality basis for the efficient recycling of mother liquor and effectively avoids problems such as reduced crystal quality and equipment scaling caused by the enrichment of impurities.

[0016] (2) This invention achieves a high degree of automation and improved operational stability in the mother liquor treatment process through the integration of the sedimentation tank and the separation cylinder and the linkage of multiple components: the rotating shaft synchronously drives the stirring frame, the fixed frame, the sealing cone seat and the liquid blocking seat to work together. The stirring frame enhances the mixing reaction between the reagent and the mother liquor, and the reciprocating lifting motion of the sealing cone seat assists in mixing and vibrating to desorb the precipitate. The linkage between the liquid blocking seat and the sealing cone seat avoids the residue of precipitate during the drainage process. The precipitate is collected by the collection plate and the elastic scraper, which effectively avoids the risk of scale buildup inside the equipment and reduces the frequency of maintenance. It significantly improves the continuous operation capability of the system, reduces the operation and maintenance cost, and fully adapts to the long-term stable operation requirements of industrial-scale inorganic salt mother liquor treatment. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings; Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of a single sedimentation tank and separation cylinder of the present invention; Figure 3 This is a schematic diagram of the internal structure of the sedimentation tank and separation cylinder of the present invention; Figure 4 This is a schematic diagram of the linkage between the sealing cone seat and the liquid plugging seat of the present invention. Figure 1 ; Figure 5 This is a schematic diagram of the linkage between the sealing cone seat and the liquid plugging seat of the present invention. Figure 2 ; Figure 6 This is a schematic diagram showing the disassembled rotating shaft and rotating plate of the present invention; Figure 7 This is a schematic diagram of the rotating column of the present invention; Figure 8 This is a schematic diagram of the sealing cone seat of the present invention.

[0018] Legend: 1. Sedimentation tank; 11. Separation cylinder; 12. Liquid storage hopper; 13. Drain pipe; 14. Peristaltic pump; 15. Sand filter tank; 16. Activated carbon adsorption tank; 17. Ion exchange resin tank; 18. Filter cover; 19. Liquid blocking seat; 110. Guide wheel; 111. Connecting rope; 112. Vertical rod; 113. Rubber elastic layer; 2. Sealing cone seat; 21. Rotating column; 22. Upper annular groove; 23. Lower annular groove; 24. Spiral groove; 25. Triangular connecting port; 26. Guide pin; 27. Limiting plate; 28. Spring II; 29. ​​Collection tray; 210. Rotating plate; 211. Elastic scraper; 3. U-shaped frame; 31. Rotating shaft; 32. Stirring rack; 33. Fixing frame; 34. Brush plate; 35. Spring 1. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Please refer to Figure 1 - Figure 8 As shown, the following solutions can be used to address the problem that the mother liquor's impurity concentration increases exponentially with the number of cycles because the graded reuse path was not designed based on the differences in impurity ion concentrations in the mother liquor. In this embodiment, the inorganic salt mother liquor recycling system based on MVR evaporation crystallization includes three sets of precipitation tanks 1. The three sets of precipitation tanks 1 are used for graded treatment to achieve targeted and stepwise removal of impurities, avoiding waste of reagents or excessive introduction of new impurities. Separation cylinders 11 are fixedly connected to the bottom of each precipitation tank 1. The separation cylinder 11 is equipped with a stirring assembly and a sealing cone seat 2. The top of the precipitation tank 1 is connected to a storage hopper 12 through a liquid inlet pipe. An electromagnetic control valve is installed on the liquid inlet pipe. By controlling the opening time of the electromagnetic control valve, an appropriate amount of solution in the storage hopper 12 is injected into the precipitation tank 1. The contents of the multiple storage hoppers 12 are arranged from left to right as calcium hydroxide solution, sodium carbonate solution and barium chloride solution. An appropriate amount of calcium hydroxide solution in storage tank 12 is injected into the left precipitation tank 1. The hydroxide ions dissociated from the calcium hydroxide solution react with magnesium ions in the mother liquor to form magnesium hydroxide precipitate. At the same time, the pH value is increased to create an alkaline environment for subsequent sodium carbonate removal of calcium ions. An appropriate amount of sodium carbonate solution in storage tank 12 is injected into the middle precipitation tank 1. Under alkaline conditions, sodium carbonate dissociates into carbonate ions, which react with free calcium ions in the mother liquor and calcium ions introduced by calcium hydroxide to form calcium carbonate precipitate. An appropriate amount of barium chloride solution in storage tank 12 is injected into the right precipitation tank 1. The barium ions dissociated from barium chloride react with sulfate ions to form stable barium sulfate precipitate, thus achieving graded treatment of the mother liquor. The bottom of the separation cylinder 11 is fixedly connected to a drain pipe 13, and a peristaltic pump 14 is connected to each drain pipe 13. The peristaltic pump 14 effectively prevents additional pollution during the mother liquor transportation process. The top of the left sedimentation tank 1 is equipped with an injection pipe for injecting inorganic salt mother liquor. The free ends of the left drain pipe 13 and the middle drain pipe 13 are fixedly connected to the middle sedimentation tank 1 and the right sedimentation tank 1, respectively. From left to right, the drain pipe 13 on the right side is equipped with a sand filter tank 15, an activated carbon adsorption tank 16, and an ion exchange resin tank 17. The progressive deep purification of the sand filter tank 15, activated carbon adsorption tank 16, and ion exchange resin tank 17 can further intercept suspended solids, residual barium ions, and trace amounts of calcium and magnesium ions, reducing the concentration of impurities in the treated mother liquor to the range suitable for MVR evaporation and crystallization. This provides a high-quality water quality foundation for the efficient recycling of the mother liquor and effectively avoids problems such as decreased crystal quality and equipment scaling caused by the enrichment of impurities.

[0021] The bottom of the separator 11 is provided with a discharge port that is slidably connected to the sealing cone seat 2. The bottom of the separator 11 is fixedly connected to the filter cover 18 outside the discharge port. The inlet of the drain pipe 13 is located outside the filter cover 18. The outer wall of the filter cover 18 and the inner wall of the separator 11 are slidably connected to a plugging seat 19 for blocking the inlet of the drain pipe 13. During the thorough mixing of the impurity removal solution and the mother liquor, precipitates continuously precipitate out until the reaction is complete. The plugging seat 19 rises to a certain height, causing the bottom of the plugging seat 19 to separate from the bottom of the separation cylinder 11. The mother liquor with removed impurities is filtered by the filter cover 18 and then enters the separation cylinder 11 below the plugging seat 19, and then enters the corresponding drain pipe 13 to prevent precipitates from entering the subsequent drain pipe 13 and causing blockage. The peristaltic pump 14 is started to pump all the filtered mother liquor to the next stage sedimentation tank 1 for multi-stage treatment. The top of the liquid blockage seat 19 is provided with an inclined surface, that is, the height of the top of the inner ring is lower than the height of the top of the outer ring. As a result, during the impurity discharge process, the sediment on the top of the liquid blockage seat 19 is carried to the top of the filter cover 18 by the upward movement of the liquid blockage seat 19. Combined with the inclined surface of the top of the liquid blockage seat 19, the sediment is assisted to enter the interior of the filter cover 18 and be discharged and collected.

[0022] A U-shaped frame 3 is fixedly connected to the bottom of the separation cylinder 11, and a rotating shaft 31 is rotatably connected between the U-shaped frame 3 and the top of the sedimentation tank 1. A motor that drives the rotating shaft 31 to rotate is installed on the U-shaped frame 3 by bolts. Multiple stirring racks 32 are fixedly connected to the rotating shaft 31 inside the sedimentation tank 1, and multiple fixed racks 33 are fixedly connected to the rotating shaft 31 inside the filter cover 18. When the impurity removal solution and the mother liquor are mixed, the motor drives the rotating shaft 31 to rotate. The rotating shaft 31 drives the stirring racks 32 and the fixed racks 33 to rotate in the sedimentation tank 1 and the separation cylinder 11 respectively, so as to fully and quickly mix the impurity removal solution and the mother liquor and improve the reaction efficiency.

[0023] A brush plate 34 is slidably connected to the fixed frame 33, and the bottom of the brush plate 34 is in contact with the top of the sealing cone seat 2. An ear block is fixedly connected to the brush plate 34, and a spring 35 is fixedly connected between the top and bottom sides of the ear block and the fixed frame 33. The multiple brush plates 34 are driven to rotate synchronously through the rotating shaft 31, which further accelerates the stirring efficiency and cleans the precipitate in the filter holes of the filter cover 18 to avoid clogging and affecting the discharge of the clear liquid.

[0024] Guide wheels 110 are fixedly connected to the bottom of the separation cylinder 11 and the outer wall of the U-shaped frame 3, and the guide wheels 110 are connected to each other by a connecting rope 111. A vertical rod 112 that extends through to the outside of the bottom of the separation cylinder 11 is fixedly connected to the bottom of the liquid blocking seat 19. A sealing ring that slides with the vertical rod 112 is installed on the separation cylinder 11 to prevent the solution from leaking from the vertical rod 112. The end of the vertical rod 112 and the limiting plate 27 are fixedly connected to the connecting rope 111. A rubber elastic layer 113 is fixedly connected to the bottom of the liquid blocking seat 19. During the descent of the sealing cone seat 2, the connecting rope 111 is rotated by the limiting plate 27. The connecting rope 111 synchronously drives the liquid blocking seat 19 to rise, causing the rubber elastic layer 113 at the bottom of the liquid blocking seat 19 to separate from the bottom of the separation cylinder 11. The clear liquid is filtered and discharged first, and then the sealing cone seat 2 slides out from the impurity discharge port of the separation cylinder 11, and the liquid blocking seat 19 rises synchronously. The rubber elastic layer 113 is used to increase the contact sealing between the bottom of the liquid blocking seat 19 and the separation cylinder 11, and to avoid interference with the small-amplitude lifting and lowering movement of the liquid blocking seat 19 and solution leakage.

[0025] The precipitation tank 1 is equipped with a control component, which includes an ion-selective electrode sensor embedded in the inner wall of the precipitation tank 1 and a controller electrically connected to the ion-selective electrode sensor. The concentrations of magnesium ions in the left precipitation tank 1, calcium ions in the middle precipitation tank 1, and sulfate ions in the right precipitation tank 1 are detected by ion selective electrode sensors. The detected ion concentration values ​​are transmitted to the controller, which controls the opening time of the corresponding electromagnetic control valve to inject an appropriate amount of the corresponding impurity removal solution into the corresponding precipitation tank 1 to remove the corresponding impurity ions.

[0026] Example 2: Please refer to Figure 3 - Figure 8 As shown, the following solutions can be used to address the issue of ensuring complete and rapid removal of sediment and preventing subsequent pipe blockage. In this embodiment, a rotating column 21 is fixedly connected to the rotating shaft 31 and movably connected to the sealing cone seat 2. A sealing ring that is slidably connected to the rotating column 21 is embedded in the inner wall of the sealing cone seat 2 to increase the sealing between the two. An upper ring groove 22 and a lower ring groove 23 are opened on the annular outer wall of the rotating column 21. Two sets of spiral grooves 24 are opened between the upper ring groove 22 and the lower ring groove 23. Triangular communication ports 25 that communicate with the upper ring groove 22 and the lower ring groove 23 are opened at both ends of the spiral groove 24. Two sets of guide pins 26 that are adapted to the corresponding spiral grooves 24 are fixedly connected to the inner wall of the sealing cone seat 2. When the solution is mixed, the guide pin 26 is located in the upper ring groove 22, and the rotating shaft 31 synchronously carries the rotating column 21 to rotate. When the triangular connecting port 25 at the upper end of the spiral groove 24 rotates to below the guide pin 26, the mother liquor gravity and the downward elastic force of the brush plate 34 by the spring 35 cause the sealing cone seat 2 to move downward. The guide pin 26 enters the triangular connecting port 25. Then the rotating column 21 rotates and guides the guide pin 26 through the triangular connecting port 25 to cause the sealing cone seat 2 to reset and rise. This drives the sealing cone seat 2 to move up and down at small intervals, further assisting in the full mixing efficiency of the impurity removal solution and the mother liquor. In addition, the brush plate 34, which combines circumferential rotation and reciprocating lifting to form a reset motion, brushes the filter cover 18, further improving the cleaning effect on the precipitates generated inside the filter holes. The motor drives the rotating shaft 31 to rotate in the opposite direction, and the guide pin 26 on the sealing cone seat 2 enters the triangular communication port 25 from the upper ring groove 22, and then enters the spiral groove 24. After being guided by the spiral groove 24, the guide pin 26 is located in the lower ring groove 23, pushing the sealing cone seat 2 to descend, realizing the drainage and impurity removal process.

[0027] The sealing cone seat 2 is fixedly connected to the two sides of the limiting plate 27 which is slidably connected to the U-shaped frame 3. The bottom of the sealing cone seat 2 is rotatably connected to the turntable, and the bottom of the turntable is fixedly connected to the second spring 28. After the guide pin 26 enters the lower ring groove 23 from the spiral groove 24, the bottom of the second spring 28 abuts against the rotating plate 210, generating an upward elastic thrust on the sealing cone seat 2. When the triangular connecting port 25 at the lower end of the spiral groove 24 rotates to the top of the guide pin 26, the guide pin 26 enters the triangular connecting port 25. Then the rotating column 21 rotates and guides the guide pin 26 through the triangular connecting port 25, causing the sealing cone seat 2 to reset and descend, and once again drive the sealing cone seat 2 to move up and down at small intervals. The vibration of the sealing cone seat 2 assists the falling of the sediment at its top.

[0028] A collection tray 29 is fixedly connected to the top of the U-shaped frame 3. A rotating plate 210 is installed inside the collection tray 29, and multiple elastic scrapers 211 are fixedly connected to the annular outer wall of the rotating plate 210. The free ends of the elastic scrapers 211 slide against the arc-shaped inner wall of the collection tray 29 to improve the discharge effect of impurities. The rotating plate 210 is fixedly installed to the rotating shaft 31 through a one-way bearing. A discharge hopper is installed on one side of the collection tray 29. The sealing cone seat 2 vibrates to assist the sediment at the top of the cone seat to fall into the collection tray 29. The rotating shaft 31 drives the rotating plate 210 to rotate through the one-way bearing. The multiple elastic scrapers 211 rotate inside the collection tray 29, pushing the sediment from the collection tray 29 into the discharge hopper. The discharge hopper is tilted to collect the sediment.

[0029] Example 3: Please refer to Figure 1 - Figure 8 As shown, the present invention also proposes a method for using an inorganic salt mother liquor recycling system based on MVR evaporation crystallization, comprising the following steps: Step 1: The inorganic salt mother liquor obtained by MVR evaporation and crystallization is injected into the left precipitation tank 1. The magnesium ion concentration in the mother liquor is detected by the ion selective electrode sensor and the detected magnesium ion concentration value is transmitted to the controller. The controller controls the opening time of the left electromagnetic control valve and injects an appropriate amount of calcium hydroxide solution from the storage tank 12 into the left precipitation tank 1. Step 2: The controller then controls the motor to drive the rotating shaft 31 to rotate. The rotating shaft 31 drives the stirring frame 32 and the fixed frame 33 to rotate in the sedimentation tank 1 and the separation cylinder 11 respectively, so as to fully mix the calcium hydroxide solution and the mother liquor. The hydroxide ions dissociated from the calcium hydroxide solution react with the magnesium ions in the mother liquor to form magnesium hydroxide precipitate. At the same time, the pH value is increased to create an alkaline environment for subsequent sodium carbonate to remove calcium ions. The rotating shaft 31 synchronously carries the rotating column 21 to rotate. The guide pin 26 is located in the upper ring groove 22. When the triangular connecting port 25 at the upper end of the spiral groove 24 rotates to below the guide pin 26, the sealing cone seat 2 moves downward due to the gravity of the mother liquor and the elastic force of the brush plate 34 under the spring 35. The guide pin 26 enters the triangular connecting port 25. Then the rotating column 21 rotates and guides the guide pin 26 through the triangular connecting port 25, causing the sealing cone seat 2 to reset and rise. This drives the sealing cone seat 2 to move up and down at small intervals, further assisting the full mixing efficiency of the calcium hydroxide solution and the mother liquor. In addition, the brush plate 34, which combines circumferential rotation and reciprocating up and down to form a reset motion, brushes the filter cover 18 and cleans the precipitates generated inside the filter holes. Step 3: After the removal of magnesium ions from calcium hydroxide, the motor drives the rotating shaft 31 to rotate in the opposite direction. The guide pin 26 on the sealing cone seat 2 enters the triangular connecting port 25 from the upper ring groove 22, and then enters the spiral groove 24. Guided by the spiral groove 24, the sealing cone seat 2 is pushed down. During the descent of the sealing cone seat 2, the connecting rope 111 is driven to rotate through the limiting plate 27. The connecting rope 111 drives the liquid blocking seat 19 to rise, causing the rubber elastic layer 113 at the bottom of the liquid blocking seat 19 to separate from the bottom of the separation cylinder 11. At this time, the motor is stopped. The mother liquor for removing magnesium ions is filtered through the filter cover 18 and enters the drain pipe 13. The peristaltic pump 14 is started to pump all the filtered mother liquor to the middle sedimentation tank 1. Then the motor runs again to slide the sealing cone seat 2 out of the discharge port of the separation cylinder 11. The guide pin 26 enters the lower ring groove 23 from the spiral groove 24. The bottom of the spring 28 abuts against the rotating plate 210, generating an upward elastic thrust on the sealing cone seat 2. When the triangular connecting port 25 at the lower end of the spiral groove 24 rotates to above the guide pin 26, the guide pin 26 enters the triangular connecting port 25. The rotating column 21 rotates and guides the guide pin 26 through the triangular connecting port 25, causing the sealing cone seat 2 to reset and descend. It then drives the sealing cone seat 2 to move up and down in small intervals. The vibration of the sealing cone seat 2 assists the falling of the sediment at its top. The sediment falls into the collection tray 29. The rotating shaft 31 drives the rotating plate 210 to rotate through the one-way bearing. Multiple elastic scrapers 211 rotate in the collection tray 29, pushing the sediment out of the collection tray 29 for centralized collection. During the secondary descent of the sealing cone seat 2, the liquid blocking seat 19 rises in sync, bringing the sediment on the top of the liquid blocking seat 19 to the top of the filter cover 18. Combined with the inclined surface of the top of the liquid blocking seat 19, the sediment enters the interior of the filter cover 18 and is discharged and collected. Step 4: The mother liquor entering the intermediate sedimentation tank 1 is tested for calcium ion concentration using an ion-selective electrode sensor. The detected calcium ion concentration value is transmitted to the controller, which controls the opening time of the intermediate electromagnetic control valve. An appropriate amount of sodium carbonate solution in the storage hopper 12 is injected into the intermediate sedimentation tank 1. Under alkaline conditions, sodium carbonate dissociates into carbonate ions, which react with free calcium ions in the mother liquor and calcium ions introduced by calcium hydroxide to form calcium carbonate precipitate. Then, the mother liquor is filtered twice and the precipitate is removed. Step 5: The mother liquor after calcium ion removal is completely pumped to the right sedimentation tank 1 through the corresponding drain pipe 13 and peristaltic pump 14. The concentration of sulfate ions in the mother liquor is detected by the ion selective electrode sensor and the detected sulfate ion concentration value is transmitted to the controller. The controller controls the opening time of the right electromagnetic control valve and injects an appropriate amount of barium chloride solution from the storage hopper 12 into the right sedimentation tank 1. The barium ions dissociated from the barium chloride react with the sulfate ions to form a stable barium sulfate precipitate. Then, the mother liquor is filtered three times and the precipitate is removed. Step Six: After completing the three-stage treatment of the mother liquor, the clear liquor sequentially enters the sand filter tank 15 to remove suspended solids, the activated carbon adsorption tank 16 to adsorb residual barium ions, and then the clear liquor ion exchange resin tank 17 to deeply adsorb residual calcium and magnesium ions, thereby completing the removal of impurities in the inorganic salt mother liquor for subsequent efficient recycling.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An inorganic salt mother liquor recycling system based on MVR evaporation crystallization, comprising three sets of sedimentation tanks (1), and a separation cylinder (11) fixedly connected to the bottom of each sedimentation tank (1), wherein the separation cylinder (11) is provided with a stirring assembly and a sealing cone seat (2), characterized in that, The top of the sedimentation tank (1) is connected to a storage tank (12) via an inlet pipe, and an electromagnetic control valve is provided on the inlet pipe. The contents of the multiple storage tanks (12) are arranged from left to right as follows: calcium hydroxide solution, sodium carbonate solution and barium chloride solution. The bottom of the separation cylinder (11) is fixedly connected to a drain pipe (13), and a peristaltic pump (14) is connected to each drain pipe (13). The free ends of the left drain pipe (13) and the middle drain pipe (13) are fixedly connected to the middle sedimentation tank (1) and the right sedimentation tank (1), respectively. From left to right, the right drain pipe (13) is provided with a sand filter tank (15), an activated carbon adsorption tank (16), and an ion exchange resin tank (17).

2. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 1, characterized in that, The bottom of the separation cylinder (11) is provided with a discharge port that is slidably connected to the sealing cone seat (2), and a filter cover (18) is fixedly connected to the bottom of the separation cylinder (11) and outside the discharge port. A plugging seat (19) for blocking the liquid inlet of the drain pipe (13) is slidably connected between the outer wall of the filter cover (18) and the inner wall of the separation cylinder (11).

3. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 2, characterized in that, The bottom of the separation cylinder (11) is fixedly connected to a U-shaped frame (3), and a rotating shaft (31) is rotatably connected between the U-shaped frame (3) and the top of the sedimentation tank (1). A motor for driving the rotating shaft (31) to rotate is installed on the U-shaped frame (3) by bolts. Multiple stirring racks (32) are fixedly connected to the rotating shaft (31) inside the sedimentation tank (1), and multiple fixing racks (33) are fixedly connected to the rotating shaft (31) inside the filter cover (18).

4. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 3, characterized in that, A brush plate (34) is slidably connected to the fixed frame (33), and the bottom of the brush plate (34) is in contact with the top of the sealing cone seat (2). An ear block is fixedly connected to the brush plate (34), and a spring (35) is fixedly connected between the top and bottom sides of the ear block and the fixed frame (33).

5. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 3, characterized in that, The rotating shaft (31) is fixedly connected to a rotating column (21) that is movably connected to the sealing cone seat (2). The rotating column (21) has an upper ring groove (22) and a lower ring groove (23) on its annular outer wall. Two sets of spiral grooves (24) are provided between the upper ring groove (22) and the lower ring groove (23). Both ends of the spiral groove (24) are provided with triangular communication ports (25) that communicate with the upper ring groove (22) and the lower ring groove (23). Two sets of guide pins (26) that are adapted to the corresponding spiral grooves (24) are fixedly connected to the inner wall of the sealing cone seat (2).

6. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 5, characterized in that, The sealing cone seat (2) is fixedly connected to the two sides of the limiting plate (27) which is slidably connected to the U-shaped frame (3). The bottom of the sealing cone seat (2) is rotatably connected to the turntable, and the bottom of the turntable is fixedly connected to the second spring (28).

7. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 6, characterized in that, The bottom of the separation cylinder (11) and the outer wall of the U-shaped frame (3) are both fixedly connected to guide wheels (110), and the guide wheels (110) are connected by a connecting rope (111). The bottom of the liquid blocking seat (19) is fixedly connected to a vertical rod (112) that extends to the outside of the bottom of the separation cylinder (11). The end of the vertical rod (112) and the limiting plate (27) are both fixedly connected to the connecting rope (111). The bottom of the liquid blocking seat (19) is fixedly connected to a rubber elastic layer (113).

8. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 3, characterized in that, A collection tray (29) is fixedly connected to the top of the U-shaped frame (3). A rotating plate (210) is provided inside the collection tray (29), and multiple elastic scrapers (211) are fixedly connected to the annular outer wall of the rotating plate (210). The rotating plate (210) is fixedly installed to the rotating shaft (31) through a one-way bearing. A discharge hopper is installed on one side of the collection tray (29).

9. The inorganic salt mother liquor recycling system based on MVR evaporation crystallization according to claim 1, characterized in that, The precipitation tank (1) is provided with a control component, which includes an ion-selective electrode sensor embedded in the inner wall of the precipitation tank (1) and a controller electrically connected to the ion-selective electrode sensor.

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