Separation device for fractional precipitation of heavy metals and recovery of crystalline salt

Abstract

The invention discloses a separation device for fractional precipitation of heavy metals and recovery of crystalline salt, and relates to the technical field of separation devices.The separation device comprises a liquid inlet buffering and blending mechanism, a complexation reaction mechanism, a fractional precipitation mechanism, a sediment separation mechanism, a crystalline salt precipitation mechanism and a crystallization salt separation mechanism, and the liquid inlet buffering and blending mechanism communicates with the complexation reaction mechanism; the fractional precipitation mechanism is communicated with the complex reaction mechanism, the sediment separation mechanism is communicated with the fractional precipitation mechanism, the fractional precipitation mechanism is communicated with the crystal salt precipitation mechanism, the crystal salt separation mechanism is communicated with the crystal salt precipitation mechanism, the liquid inlet buffering and blending mechanism is used for preliminarily buffering and blending wastewater, and the complex reaction mechanism is used for forming a complex. The device provides conditions for subsequent fractional precipitation, the fractional precipitation mechanism is used for fractional precipitation, the sediment separation mechanism is used for separation and recovery, secondary pollution is avoided, and the crystallized salt precipitation mechanism promotes crystallization and precipitation of salt in a solution.

Description

Technical Field

[0001] The present invention relates to the technical field of separation devices, and specifically to a separation device for stepwise precipitation of heavy metal recovery crystalline salts. Background Art

[0002] In recent years, heavy metal wastewater treatment technologies have developed rapidly, mainly focusing on methods such as chemical precipitation, ion exchange, membrane separation, and electrochemistry. Among them, the chemical precipitation method is widely used due to its low cost and simple operation, but the traditional process has problems such as low precipitation efficiency and high reagent consumption. With increasingly strict environmental protection requirements, high-efficiency and low-consumption heavy metal separation and resource recovery technologies have become research hotspots, especially integrated devices that combine complexation reactions, stepwise precipitation, and crystallization salt separation, which are expected to achieve synchronous recovery of heavy metals and salts and improve resource utilization rates.

[0003] In current mainstream technologies, liquid level control mostly relies on mechanical float valves or ultrasonic sensors, but the former has insufficient accuracy and the latter has a high cost; stirring devices often use fixed impellers or static mixers, and the mixing uniformity is limited; sediment separation mostly uses plate and frame filter presses or centrifuges, which have high energy consumption and are prone to clogging. In addition, existing crystallization processes usually rely on single cooling or evaporation, and the purity of crystalline salts is limited by the temperature control accuracy and insufficient solution disturbance.

[0004] The existing technology leads to unstable heavy metal separation efficiency; liquid level fluctuations easily affect reaction conditions and lack a dynamic compensation mechanism; the liquid reuse rate after sediment separation is low, and the risk of secondary pollution is high. Therefore, those skilled in the art have provided a separation device for stepwise precipitation of heavy metal recovery crystalline salts to solve the problems raised in the above background. Summary of the Invention

[0005] The purpose of the present invention is to provide a separation device for stepwise precipitation of heavy metal recovery crystalline salts to solve the problems raised in the existing technology.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: The separation device includes a feed liquid buffer and blending mechanism, a complexation reaction mechanism, a stepwise precipitation mechanism, a sediment separation mechanism, a crystalline salt precipitation mechanism, and a crystallization salt separation mechanism. The feed liquid buffer and blending mechanism is connected to the complexation reaction mechanism, the stepwise precipitation mechanism is connected to the complexation reaction mechanism, the sediment separation mechanism is connected to the stepwise precipitation mechanism, the stepwise precipitation mechanism is connected to the crystalline salt precipitation mechanism, and the crystallization salt separation mechanism is connected to the crystalline salt precipitation mechanism.

[0007] By adopting the above technical solution, the liquid inlet buffer and blending mechanism can preliminarily buffer and blend the input heavy metal-containing wastewater to ensure the stability and efficiency of subsequent treatment. The complexation reaction mechanism reacts with heavy metal ions by adding a complexing agent to form stable complexes, providing conditions for subsequent stepwise precipitation. The stepwise precipitation mechanism gradually precipitates heavy metal ions by adjusting the pH value of the solution and adding different complexing agents, achieving effective separation of heavy metals. The sediment separation mechanism separates and recovers the precipitated heavy metal residues, avoiding secondary pollution. The crystal salt precipitation mechanism promotes the crystallization and precipitation of salts in the solution by utilizing temperature differences and turbulence effects, improving the purity and recovery rate of crystal salts.

[0008] Furthermore, the liquid inlet buffer and blending mechanism includes a buffer tank, a liquid inlet pipe, a connecting pipe, an adjusting pipe, a pH pump, a liquid inlet valve, a pH sensor, a connecting valve, a stirring assembly, and a liquid level stabilizing assembly. The buffer tank is connected to the liquid inlet pipe, the buffer tank is connected to the adjusting pipe, the buffer tank is connected to the connecting pipe, the connecting pipe is connected to the connecting valve, the connecting valve is connected to the complexation reaction mechanism, the pH pump is connected to the adjusting pipe, the liquid inlet pipe is connected to the liquid inlet valve, the stirring assembly is fixedly connected to the buffer tank, the liquid level stabilizing assembly is fixedly connected to the buffer tank, and the pH sensor is fixedly connected to the buffer tank. The pH pump is used to preliminarily adjust the pH value of the original liquid, the connecting valve is used to control the flow rate into the complexation reaction mechanism, and the liquid inlet valve is used to control the flow rate of the original liquid into the buffer tank.

[0009] By adopting the above technical solution, the pH sensor can real-time monitor the pH value of the liquid in the buffer tank to ensure precise regulation of the pH value. The stirring assembly evenly mixes the liquid in the buffer tank through stirring, improving the efficiency and stability of the complexation reaction. The liquid level stabilizing assembly can maintain the stability of the liquid level in the buffer tank, avoiding the influence on the effect of the complexation reaction caused by liquid level fluctuations. The design of the entire liquid inlet buffer and blending mechanism not only ensures the stable input of the original liquid but also realizes the precise regulation of the original liquid, providing good conditions for subsequent complexation reactions.

[0010] Furthermore, the liquid level stabilizing assembly includes an upper limit liquid level probe, a lower limit liquid level probe, a first elastic member, a first electromagnetic block, a buffer cover, a float, a guide rod, a limit ring, and a one-way micro-pressure breathing valve. The buffer cover is fixedly connected to the buffer tank. There are an even number of limit rings and first electromagnetic blocks, with two limit rings and first electromagnetic blocks in each group, and one limit ring and first electromagnetic block are provided at each of the upper and lower ends of the buffer tank. The upper limit liquid level probe is fixedly connected to the limit ring, and the lower limit liquid level probe is fixedly connected to the limit ring. The guide rod is fixedly connected to the buffer cover, and the buffer cover is fixedly connected to the buffer tank. The buffer cover is provided with micro-flow guiding holes for the slow entry of liquid to reduce liquid level fluctuations. The limit ring is slidably connected to the guide rod, and the limit ring is used to control the displacement range of the float so as to correspond to the upper and lower liquid level thresholds. The upper limit liquid level probe and the lower limit liquid level probe are upper and lower conductive electrodes. The float is slidably connected to the guide rod. The one-way micro-pressure breathing valve is communicated with the buffer tank and is located above the buffer tank. The first electromagnetic block is fixedly connected to the buffer cover, the first elastic member is fixedly connected to the first electromagnetic block, the first elastic member is fixedly connected to the limit ring, and the first electromagnetic block and the limit ring are driven by magnetic repulsion.

[0011] By adopting the above technical solution, when the liquid level in the buffer tank rises, the float also rises, driving the upper limit liquid level probe and the lower limit liquid level probe fixedly connected to it to move together. When the liquid level reaches the preset upper threshold, the upper limit liquid level probe is connected to the liquid level to form a conductive path, thereby triggering a corresponding control signal. At the same time, the rise of the float also causes the limit ring to move under the repulsive force through the sliding connection between the guide rod and the limit ring and the magnetic repulsion drive between the first electromagnetic block and the limit ring. The first elastic member provides elastic force for the reset of the limit ring. When the liquid level drops, the float also drops. Similarly, when the liquid level reaches the preset lower threshold, the lower limit liquid level probe will also contact the corresponding liquid level to form a conductive path and trigger a corresponding control signal. The setting of the one-way micro-pressure breathing valve allows the gas in the buffer tank to be discharged unidirectionally when the pressure changes, thereby further stabilizing the liquid level. The design of the entire liquid level stabilizing assembly not only ensures the stable control of the liquid level but also realizes the real-time monitoring and feedback of the liquid level change, providing a reliable guarantee for the subsequent complex reaction.

[0012] Furthermore, the stirring assembly includes a stirring rod, a spiral rod, a universal coupling, a hinge block, a stirring motor, a moving block, a transmission bevel gear, a second electromagnetic block, a third electromagnetic block, and a second elastic member. The stirring motor is fixedly connected to the buffer tank, the stirring motor is drivingly connected to the stirring rod, the moving block is fixedly connected to the third electromagnetic block, the second elastic member is fixedly connected to the second electromagnetic block, the second elastic member is fixedly connected to the moving block, the second electromagnetic block and the moving block are attracted to each other magnetically for driving, the third electromagnetic block and the moving block are attracted to each other magnetically for driving, the moving block is slidably connected to the stirring rod, the moving block is drivingly connected to the transmission bevel gear, the transmission bevel gear is slidably connected to the third electromagnetic block, the transmission bevel gear is slidably connected to the stirring rod, the transmission bevel gear is drivingly connected to the universal coupling, the universal coupling is hinged to the spiral rod, and the spiral rod is hinged to the hinge block.

[0013] By adopting the above technical solution, when the stirring motor is started, its power is transmitted to the stirring rod, causing the stirring rod to start rotating. At the same time, the second electromagnetic block and the third electromagnetic block generate an attractive force on the moving block through magnetic attraction, causing the moving block to slide on the stirring rod. Due to the presence of the second elastic member, it provides certain elastic support and reset function for the moving block. As the stirring rod rotates, the moving block transmits power to the spiral rod through the sliding connection between the transmission bevel gear and the stirring rod and the driving connection between the transmission bevel gear and the universal coupling. Under the action of the universal coupling, the spiral rod can rotate around the axis of the stirring rod and maintain a certain angle with the stirring rod through the hinge block, thereby achieving the stirring effect of self-rotation and revolution, ensuring both the uniformity and efficiency of stirring, and realizing flexible adjustment of the stirring amplitude through the cooperation of the electromagnetic block and the elastic member, improving the adaptability and stability of the device.

[0014] Furthermore, the complexing reaction mechanism includes a complexing motor, a complexing tank, a first stirrer, a liquid storage barrel, a metering pump, a circulation pump, a circulation pipe, a heating box, a cooling box, and a vibration assembly. The complexing motor is fixedly connected to the complexing tank, the complexing motor is drivingly connected to the first stirrer, the liquid storage barrel is communicated with the metering pump, the metering pump is communicated with the complexing tank, the complexing tank is communicated with a communication valve, the circulation pipe is communicated with the cooling box, the circulation pump is communicated with the heating box, the heating box is communicated with the circulation pump, the circulation pump is communicated with the cooling box, the circulation pipe surrounds inside the complexing tank, the vibration assembly includes an eccentric wheel, a vibration block, and a vibration frame, the vibration block is slidably connected to the vibration frame, the eccentric wheel is drivingly connected to the vibration block, and the first stirrer is drivingly connected to the eccentric wheel.

[0015] By adopting the above technical solution, after the complexing motor starts, its power is transmitted to the first stirrer, causing the first stirrer to rotate in the complexing tank and stir the liquid in the complexing tank. At the same time, the metering pump quantitatively pumps the complexing agent in the liquid storage barrel into the complexing tank to carry out a complexing reaction with heavy metal ions. The circulation pump, through the cooperation of the heating box and the cooling box, heats and cools the liquid in the circulation pipe to control the temperature of the complexing reaction. The eccentric wheel of the oscillation assembly rotates driven by the first stirrer. Through the sliding connection of the oscillation block and the oscillation frame, the oscillation frame generates reciprocating oscillations, further improving the efficiency and uniformity of the complexing reaction. The design of the entire complexing reaction mechanism not only ensures the stable progress of the complexing reaction but also realizes the precise control of the complexing reaction conditions, providing good conditions for the subsequent fractional precipitation.

[0016] Further, the fractional precipitation mechanism includes a precipitation tank, a pH probe, a chemical pump, an acidic chemical barrel, a basic chemical barrel, a discharge valve, and an overflow pipe. The precipitation tank is connected to the overflow pipe, and the overflow pipe is used to automatically overflow the liquid to the next precipitation stage when the liquid level reaches the set height. The chemical pump is connected to the precipitation tank, and both the acidic chemical barrel and the basic chemical barrel are connected to the chemical pump. The precipitation tank is connected to the discharge valve, and the discharge valve is located at the bottom of the precipitation tank and is connected to the slag separation mechanism.

[0017] By adopting the above technical solution, the pH value in the precipitation tank is monitored in real time by the pH probe to ensure the precise control of the precipitation reaction. When it is necessary to adjust the pH value, the chemical pump pumps the chemical in the acidic chemical barrel or the basic chemical barrel into the precipitation tank to react with the complex, causing the heavy metal ions to gradually precipitate. As the precipitation reaction progresses, the liquid level gradually rises. When the liquid level reaches the set height, the overflow pipe automatically overflows the excess liquid to the next precipitation stage, achieving the effect of fractional precipitation. When the precipitation is completed, the discharge valve is opened, and the precipitated heavy metal slag falls into the slag separation mechanism under the action of gravity for further treatment. The design of the entire fractional precipitation mechanism not only ensures the stable progress of the precipitation reaction but also realizes the precise control of the precipitation conditions, effectively improving the separation efficiency and purity of heavy metals.

[0018] Further, the slag separation mechanism includes a drum filter, a return pipe, a slag scraping motor, a pressing elastic member, a scraper, and a scraping shaft. The slag scraping motor is fixedly connected to the drum filter, the slag scraping motor is drivingly connected to the scraping shaft, the scraping shaft is fixedly connected to the pressing elastic member, the pressing elastic member is fixedly connected to the scraper, the scraping shaft is drivingly connected to the scraper, the return pipe is connected to the precipitation tank, and the drum filter is connected to the discharge valve.

[0019] By adopting the above technical solution, after the scraper motor is started, its power is transmitted to the scraper shaft, causing the scraper shaft to start rotating. The clamping elastic member provides a certain elastic support for the scraper to ensure that the scraper fits tightly with the surface of the drum filter. As the scraper shaft rotates, the scraper slides on the surface of the drum filter to scrape off the heavy metal slag attached to the drum filter. The scraped heavy metal slag falls into the collection device below through the drum filter, while the liquid that is not scraped off flows back into the sedimentation tank through the reflux pipe, achieving effective separation of the sediment. The design of the entire sediment separation mechanism not only ensures the complete separation of the sediment, but also avoids secondary contamination of the liquid, providing good conditions for subsequent treatment.

[0020] Furthermore, the crystallization salt precipitation mechanism includes a double-layer coil crystallization tank, a temperature probe and a spoiler, the spoiler is provided with a guide groove, a polytetrafluoroethylene ball is embedded in the guide groove, the temperature probe and the double-layer coil crystallization tank are tightly connected, the spoiler and the double-layer coil crystallization tank are tightly connected, the upper layer of the double-layer coil crystallization tank is used to transport high-temperature steam, and the upper and lower layers of the double-layer coil crystallization tank are used to transport cooling water.

[0021] By adopting the above technical solutions, the design of the double-layer coil crystallization tank fully utilizes the effect of temperature difference on salt crystallization. High-temperature steam circulates in the upper layer of the double-layer coil crystallization tank, providing the necessary heat for the solution, promoting the dissolution of salt and the active movement of ions. The cooling water transported from the bottom layer quickly takes away the heat, forming a significant temperature gradient. This temperature difference prompts the salt in the solution to crystallize rapidly within the appropriate temperature range. The guide groove and polytetrafluoroethylene ball design on the spoiler further enhance the turbulence effect of the solution during the crystallization process, allowing the salt in the solution to contact the cooling surface more evenly, thereby improving the crystallization efficiency and the purity of the salt. The design of the entire crystallization salt precipitation mechanism not only ensures the efficient crystallization of the salt, but also achieves a double improvement in the purity and recovery rate of the crystallized salt through precise temperature control and turbulence.

[0022] Furthermore, the crystallization and salt separation mechanism includes a spiral filter press, a vibrating screen, a salt outlet hopper, a filtrate pipe and a salt separation box. The spiral filter press is connected to the double-layer coil crystallization tank, the spiral filter press is connected to the salt outlet hopper, the salt outlet hopper is connected to the vibrating screen, and the vibrating screen is connected to the salt separation box.

[0023] By adopting the above technical solution, the spiral filter press can preliminarily press and dehydrate the crystal salts precipitated in the double-layer coil crystallization tank, removing the excess water and impurities therein. The pressed crystal salts enter the salt discharge hopper through the outlet of the spiral filter press, and the design of the salt discharge hopper ensures that the crystal salts can flow smoothly into the subsequent vibrating sieve. The vibrating sieve further screens and classifies the crystal salts through vibration, removing the fine particles and impurities therein to obtain relatively pure crystal salts. Finally, the screened crystal salts enter the salt separation tank through the outlet of the vibrating sieve, realizing the effective separation and recovery of the crystal salts.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The liquid level stabilizing assembly drives through the repulsion of the magnetic poles of the float, guide rod, limit ring and electromagnetic block, and combines with the conductive feedback of the upper and lower limit liquid level probes to monitor and control the liquid level of the buffer tank in real time. The one-way micro-pressure breathing valve balances the air pressure in the tank, and cooperates with the micro-guide holes of the buffer cover to slow down the liquid level fluctuation, ensuring the stability of the liquid input before the complexation reaction. The stirring assembly adopts the articulated design of the spiral rod and the universal coupling, and drives the moving block to slide through the electromagnetic block, driving the transmission bevel gear to realize the self-rotation and revolution of the stirring rod, improving the mixing uniformity; the stepwise precipitation mechanism links the pH probe with the chemical pump to accurately add acidic / alkaline agents and adjust the pH value in segments to gradually precipitate heavy metal ions. The overflow pipe realizes the automatic segmented overflow of the liquid level, and combines with the pressing elastic member of the rotary drum filter to ensure that the scraper fits, the scraping shaft rotates to scrape off the sediment, the separated slag is discharged through the discharge valve, and the liquid is recycled through the return pipe to avoid secondary pollution; the double-layer coil crystallization tank utilizes the temperature difference between the upper and lower layers of high-temperature steam and cooling water to form a temperature gradient for salt precipitation; the polytetrafluoroethylene balls of the spoiler enhance the solution turbulence and improve the crystallization purity. After the spiral filter press presses and dehydrates the crystal salts, the vibrating sieve screens different particle size salt grains through high-frequency vibration, and finally is collected by the salt separation tank to realize the efficient recovery of salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the structure of the liquid inlet buffer and dispensing mechanism of the present invention; Figure 3 It is a schematic diagram of the structure of the liquid level stabilizing assembly of the present invention; Figure 4 It is a schematic diagram of the structure of the stirring assembly of the present invention; Figure 5 It is a schematic diagram of the structure of the complexation reaction mechanism of the present invention; Figure 6 It is a schematic diagram of the structure of the oscillating assembly of the present invention; Figure 7 It is a schematic diagram of the structure of the stepwise precipitation mechanism of the present invention; Figure 8 Structural schematic diagram of the sediment separation mechanism of the present invention; Figure 9 Structural schematic diagram of the crystal salt precipitation mechanism of the present invention; Figure 10 Structural schematic diagram of the crystal salt separation mechanism of the present invention.

[0026] In the figure: 1. Liquid inlet buffer and blending mechanism; 11. Buffer tank; 12. Liquid inlet pipe; 13. Connecting pipe; 14. Adjusting pipe; 15. pH pump; 16. Liquid inlet valve; 17. pH sensor; 18. Connecting valve; 19. Stirring assembly; 191. Stirring rod; 192. Screw rod; 193. Universal coupling; 194. Hinge block; 195. Stirring motor; 196. Moving block; 197. Driving bevel gear; 198. Second electromagnetic block; 199. Third electromagnetic block; 1910. Second elastic member; 110. Liquid level stabilizing assembly; 1101. Upper limit liquid level probe; 1102. Lower limit liquid level probe; 1103. First elastic member; 1104. First electromagnetic block; 1105. Buffer cover; 11051. Micro diversion hole; 1106. Floating cylinder; 1107. Guide rod; 1108. Limit ring; 1109. One-way micro pressure breathing valve; 2. Complexation reaction mechanism; 21. Complexation motor; 22. Complexation tank; 23. First stirrer; 24. Liquid storage bucket; 25. Dosing pump; 26. Circulation pump; 27. Circulation pipe; 28. Heating box; 29. Cooling box; 210. Oscillation assembly; 2101. Eccentric wheel; 2102. Oscillation block; 2103. Oscillation frame; 3. Stepwise precipitation mechanism; 31. Precipitation tank; 32. pH probe; 33. Chemical pump; 34. Acidic chemical agent bucket; 35. Alkaline chemical agent bucket; 36. Discharge valve; 37. Overflow pipe; 4. Sediment separation mechanism; 41. Drum filter; 42. Return pipe; 43. Scraper motor; 44. Compression elastic member; 45. Scraper; 46. Scraping shaft; 5. Crystal salt precipitation mechanism; 51. Double-layer coil crystallization tank; 52. Temperature probe; 53. Turbulence plate; 531. Guide groove; 532. Polytetrafluoroethylene ball; 6. Crystal salt separation mechanism; 61. Screw filter press; 62. Vibration sieve; 63. Salt outlet hopper; 64. Filtrate pipe; 65. Salt separation box. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 - Figure 10As shown, the present invention provides a technical solution for a separation device for stepwise precipitation of heavy metal recovery crystalline salts: The separation device includes a feed liquid buffer and blending mechanism 1, a complexation reaction mechanism 2, a stepwise precipitation mechanism 3, a sediment separation mechanism 4, a crystalline salt precipitation mechanism 5 and a crystalline salt fractionation mechanism 6. The feed liquid buffer and blending mechanism 1 is connected to the complexation reaction mechanism 2, the stepwise precipitation mechanism 3 is connected to the complexation reaction mechanism 2, the sediment separation mechanism 4 is connected to the stepwise precipitation mechanism 3, the stepwise precipitation mechanism 3 is connected to the crystalline salt precipitation mechanism 5, and the crystalline salt fractionation mechanism 6 is connected to the crystalline salt precipitation mechanism 5.

[0029] By adopting the above technical solution, the feed liquid buffer and blending mechanism 1 can preliminarily buffer and blend the input heavy metal-containing wastewater to ensure the stability and efficiency of subsequent treatment. The complexation reaction mechanism 2 reacts with heavy metal ions by adding a complexing agent to form a stable complex, providing conditions for subsequent stepwise precipitation. The stepwise precipitation mechanism 3 gradually precipitates heavy metal ions by adjusting the pH value of the solution and adding different complexing agents, achieving effective separation of heavy metals. The sediment separation mechanism 4 separates and recovers the precipitated heavy metal slag to avoid secondary pollution. The crystalline salt precipitation mechanism 5 promotes the crystallization and precipitation of salts in the solution by using temperature difference and turbulence, improving the purity and recovery rate of the crystalline salts.

[0030] Furthermore, the feed liquid buffer and blending mechanism 1 includes a buffer tank 11, a feed liquid pipe 12, a connecting pipe 13, an adjusting pipe 14, a pH pump 15, a feed liquid valve 16, a pH sensor 17, a connecting valve 18, a stirring assembly 19 and a liquid level stabilizing assembly 110. The buffer tank 11 is connected to the feed liquid pipe 12, the buffer tank 11 is connected to the adjusting pipe 14, the buffer tank 11 is connected to the connecting pipe 13, the connecting pipe 13 is connected to the connecting valve 18, the connecting valve 18 is connected to the complexation reaction mechanism 2, the pH pump 15 is connected to the adjusting pipe 14, the feed liquid pipe 12 is connected to the feed liquid valve 16, the stirring assembly 19 is fixedly connected to the buffer tank 11, the liquid level stabilizing assembly 110 is fixedly connected to the buffer tank 11, and the pH sensor 17 is fixedly connected to the buffer tank 11. The pH pump 15 is used to preliminarily adjust the pH value of the original liquid, the connecting valve 18 is used to control the flow rate into the complexation reaction mechanism 2, and the feed liquid valve 16 is used to control the flow rate of the original liquid into the buffer tank 11.

[0031] By adopting the above technical solution, the pH sensor 17 can monitor the pH value of the liquid in the buffer tank 11 in real time, ensuring the precise regulation of the pH value. The stirring assembly 19, through the stirring action, makes the liquid in the buffer tank 11 evenly mixed, improving the efficiency and stability of the complexation reaction. The liquid level stabilizing assembly 110 can keep the liquid level in the buffer tank 11 stable, avoiding the influence on the effect of the complexation reaction caused by the liquid level fluctuation. The design of the entire liquid inlet buffer and dispensing mechanism 1 not only ensures the stable input of the stock solution but also realizes the precise regulation of the stock solution, providing good conditions for the subsequent complexation reaction.

[0032] Further, the liquid level stabilizing assembly 110 includes an upper limit liquid level probe 1101, a lower limit liquid level probe 1102, a first elastic member 1103, a first electromagnetic block 1104, a buffer cover 1105, a floating cylinder 1106, a guide rod 1107, a limit ring 1108, and a one-way micro-pressure breathing valve 1109. The buffer cover 1105 is fixedly connected to the buffer tank 11. There are an even number of limit rings 1108 and first electromagnetic blocks 1104, with two in each group. One limit ring 1108 and one first electromagnetic block 1104 are provided at each of the upper and lower ends of the buffer tank 11. The upper limit liquid level probe 1101 is fixedly connected to the limit ring 1108, and the lower limit liquid level probe 1102 is fixedly connected to the limit ring 1108. The guide rod 1107 is fixedly connected to the buffer cover 1105, and the buffer cover 1105 is fixedly connected to the buffer tank 11. The buffer cover 1105 is provided with a micro-guide hole 11051 for the slow entry of the liquid to slow down the liquid level fluctuation. The limit ring 1108 is slidably connected to the guide rod 1107 and is used to control the displacement range of the floating cylinder 1106 so as to correspond to the upper and lower limit thresholds of the liquid level. The upper limit liquid level probe 1101 and the lower limit liquid level probe 1102 are upper and lower conductive electrodes. The floating cylinder 1106 is slidably connected to the guide rod 1107. The one-way micro-pressure breathing valve 1109 is communicated with the buffer tank 11 and is located above the buffer tank 11. The first electromagnetic block 1104 is fixedly connected to the buffer cover 1105, the first elastic member 1103 is fixedly connected to the first electromagnetic block 1104, the first elastic member 1103 is fixedly connected to the limit ring 1108, and the first electromagnetic block 1104 and the limit ring 1108 are driven by magnetic repulsion.

[0033] By adopting the above technical solution, when the liquid level in the buffer tank 11 rises, the buoy 1106 also rises accordingly, and drives the upper limit liquid level probe 1101 and the lower limit liquid level probe 1102 which are fixedly connected to it to move together. When the liquid level reaches the preset upper limit threshold, the upper limit liquid level probe 1101 is connected to the liquid level, forming an electrically conductive path, thereby triggering a corresponding control signal. At the same time, the rise of the buoy 1106 also drives the movement of the limit ring 1108 through the sliding connection between the guide rod 1107 and the limit ring 1108, and the magnetic pole repulsion transmission between the first electromagnetic block 1104 and the limit ring 1108, so that the limit ring 1108 moves under the action of the repulsive force. The first elastic member 1103 provides elastic force for the reset of the limit ring 1108. When the liquid level drops, the buoy 1106 drops accordingly. Similarly, when the liquid level reaches the preset lower limit threshold, the lower limit liquid level probe 1102 will also contact the corresponding liquid level, forming an electrically conductive path and triggering a corresponding control signal. The setting of the one-way micro-pressure breathing valve 1109 can allow the gas in the buffer tank 11 to be discharged unidirectionally when the pressure changes, thereby further stabilizing the liquid level. The design of the entire liquid level stabilizing assembly 110 not only ensures the stable control of the liquid level, but also realizes the real-time monitoring and feedback of the liquid level change, providing a reliable guarantee for the subsequent complex reaction.

[0034] Furthermore, the stirring assembly 19 includes a stirring rod 191, a spiral rod 192, a universal coupling 193, a hinge block 194, a stirring motor 195, a moving block 196, a transmission bevel gear 197, a second electromagnetic block 198, a third electromagnetic block 199 and a second elastic member 1910. The stirring motor 195 is fixedly connected to the buffer tank 11, the stirring motor 195 is drivingly connected to the stirring rod 191, the moving block 196 is fixedly connected to the third electromagnetic block 199, the second elastic member 1910 is fixedly connected to the second electromagnetic block 198, the second elastic member 1910 is fixedly connected to the moving block 196, the second electromagnetic block 198 and the moving block 196 are driven by magnetic pole attraction, the third electromagnetic block 199 and the moving block 196 are driven by magnetic pole attraction, the moving block 196 is slidably connected to the stirring rod 191, the moving block 196 is drivingly connected to the transmission bevel gear 197, the transmission bevel gear 197 is slidably connected to the third electromagnetic block 199, the transmission bevel gear 197 is slidably connected to the stirring rod 191, the transmission bevel gear 197 is drivingly connected to the universal coupling 193, the universal coupling 193 is hinged to the spiral rod 192, and the spiral rod 192 is hinged to the hinge block 194.

[0035] By adopting the above technical solution, when the stirring motor 195 starts, its power is transmitted to the stirring rod 191, causing the stirring rod 191 to start rotating. At the same time, the second electromagnetic block 198 and the third electromagnetic block 199 generate an attractive force on the moving block 196 through the attraction of magnetic poles, causing the moving block 196 to slide on the stirring rod 191. Due to the presence of the second elastic member 1910, it provides a certain elastic support and reset function for the moving block 196. As the stirring rod 191 rotates, the moving block 196 transmits power to the screw rod 192 through the sliding connection between the transmission bevel gear 197 and the stirring rod 191, and the transmission connection between the transmission bevel gear 197 and the universal coupling 193. Under the action of the universal coupling 193, the screw rod 192 can rotate around the axis of the stirring rod 191 and maintain a certain angle with the stirring rod 191 through the hinge block 194, thereby achieving the stirring effect of self-rotation and revolution. This not only ensures the uniformity and efficiency of stirring, but also realizes the flexible adjustment of the stirring amplitude through the cooperation of the electromagnetic block and the elastic member, improving the adaptability and stability of the device.

[0036] Further, the complexing reaction mechanism 2 includes a complexing motor 21, a complexing tank 22, a first stirrer 23, a liquid storage barrel 24, a metering pump 25, a circulation pump 26, a circulation pipe 27, a heating box 28, a cooling box 29 and a vibration assembly 210. The complexing motor 21 is fixedly connected to the complexing tank 22, the complexing motor 21 is drivingly connected to the first stirrer 23, the liquid storage barrel 24 is communicated with the metering pump 25, the metering pump 25 is communicated with the complexing tank 22, the complexing tank 22 is communicated with the communication valve 18, the circulation pipe 27 is communicated with the cooling box 29, the circulation pump 26 is communicated with the heating box 28, the heating box 28 is communicated with the circulation pump 26, the circulation pump 26 is communicated with the cooling box 29, the circulation pipe 27 is wound inside the complexing tank 22, the vibration assembly 210 includes an eccentric wheel 2101, a vibration block 2102 and a vibration frame 2103, the vibration block 2102 is slidably connected to the vibration frame 2103, the eccentric wheel 2101 is drivingly connected to the vibration block 2102, and the first stirrer 23 is drivingly connected to the eccentric wheel 2101.

[0037] By adopting the above technical solution, after the complexing motor 21 starts, its power is transmitted to the first stirrer 23, causing the first stirrer 23 to rotate in the complexing tank 22 and stir the liquid in the complexing tank 22. At the same time, the metering pump 25 quantitatively pumps the complexing agent in the liquid storage barrel 24 into the complexing tank 22, where it undergoes a complexing reaction with heavy metal ions. The circulation pump 26 heats and cools the liquid in the circulation pipe 27 through the cooperation of the heating box 28 and the cooling box 29 to control the temperature of the complexing reaction. The eccentric wheel 2101 of the oscillation assembly 210 rotates driven by the first stirrer 23. Through the sliding connection of the oscillation block 2102 and the oscillation frame 2103, the oscillation frame 2103 generates a reciprocating oscillation, further improving the efficiency and uniformity of the complexing reaction. The design of the entire complexing reaction mechanism 2 not only ensures the stable progress of the complexing reaction but also realizes the precise control of the complexing reaction conditions, providing good conditions for the subsequent fractional precipitation.

[0038] Further, the fractional precipitation mechanism 3 includes a precipitation tank 31, a pH probe 32, a chemical pump 33, an acidic reagent barrel 34, a basic reagent barrel 35, a discharge valve 36, and an overflow pipe 37. The precipitation tank 31 is communicated with the overflow pipe 37, and the overflow pipe 37 is used to automatically overflow the liquid to the next precipitation section when the liquid level reaches the set height. The chemical pump 33 is communicated with the precipitation tank 31, and both the acidic reagent barrel 34 and the basic reagent barrel 35 are communicated with the chemical pump 33. The precipitation tank 31 is communicated with the discharge valve 36. The discharge valve 36 is located at the bottom of the precipitation tank 31, and the discharge valve 36 is communicated with the slag separation mechanism 4.

[0039] By adopting the above technical solution, the pH value in the precipitation tank 31 is monitored in real time by the pH probe 32 to ensure the precise control of the precipitation reaction. When it is necessary to adjust the pH value, the chemical pump 33 pumps the reagent in the acidic reagent barrel 34 or the basic reagent barrel 35 into the precipitation tank 31 to react with the complex, causing the heavy metal ions to gradually precipitate. As the precipitation reaction progresses, the liquid level gradually rises. When the liquid level reaches the set height, the overflow pipe 37 automatically overflows the excess liquid to the next precipitation section, achieving the effect of fractional precipitation. When the precipitation is completed, the discharge valve 36 is opened, and the precipitated heavy metal slag falls into the slag separation mechanism 4 under the action of gravity for further treatment. The design of the entire fractional precipitation mechanism 3 not only ensures the stable progress of the precipitation reaction but also realizes the precise control of the precipitation conditions, effectively improving the separation efficiency and purity of heavy metals.

[0040] Furthermore, the sediment separation mechanism 4 includes a drum filter 41, a reflux pipe 42, a scraping motor 43, a clamping elastic member 44, a scraper 45 and a scraping shaft 46. The scraping motor 43 is fastened to the drum filter 41, the scraping motor 43 is transmission-connected to the scraping shaft 46, the scraping shaft 46 is fastened to the clamping elastic member 44, the clamping elastic member 44 is fastened to the scraper 45, the scraping shaft 46 is transmission-connected to the scraper 45, the reflux pipe 42 is connected to the sedimentation tank 31, and the drum filter 41 is connected to the discharge valve 36.

[0041] By adopting the above technical solution, after the scraper motor 43 is started, its power is transmitted to the scraper shaft 46, causing the scraper shaft 46 to start rotating. The clamping elastic member 44 provides a certain elastic support for the scraper 45 to ensure that the scraper 45 is tightly fitted to the surface of the drum filter 41. As the scraper shaft 46 rotates, the scraper 45 slides on the surface of the drum filter 41 to scrape off the heavy metal slag attached to the drum filter 41. The scraped heavy metal slag falls into the collection device below through the drum filter 41, while the liquid that is not scraped off flows back into the sedimentation tank 31 through the reflux pipe 42, achieving effective separation of the sediment. The design of the entire sediment separation mechanism 4 not only ensures the thorough separation of the sediment, but also avoids secondary contamination of the liquid, providing good conditions for subsequent processing.

[0042] Furthermore, the crystallization salt precipitation mechanism 5 includes a double-layer coil crystallization tank 51, a temperature probe 52 and a spoiler 53. The spoiler 53 is provided with a guide groove 531, and a polytetrafluoroethylene ball 532 is embedded in the guide groove 531. The temperature probe 52 and the double-layer coil crystallization tank 51 are tightly connected, and the spoiler 53 and the double-layer coil crystallization tank 51 are tightly connected. The upper layer of the double-layer coil crystallization tank 51 is used to transport high-temperature steam, and the upper and lower layers of the double-layer coil crystallization tank 51 are used to transport cooling water.

[0043] By adopting the above technical solution, the design of the double-layer coil crystallization tank 51 makes full use of the effect of temperature difference on salt crystallization. High-temperature steam circulates in the upper layer of the double-layer coil crystallization tank 51, providing the necessary heat for the solution, promoting the dissolution of salt and the active movement of ions. The cooling water transported from the bottom layer quickly takes away the heat, forming a significant temperature gradient. This temperature difference prompts the salt in the solution to crystallize rapidly within a suitable temperature range. The guide groove 531 and polytetrafluoroethylene ball 532 design on the spoiler 53 further enhance the turbulence effect of the solution during the crystallization process, so that the salt in the solution can contact the cooling surface more evenly, thereby improving the crystallization efficiency and the purity of the salt. The design of the entire crystallization salt precipitation mechanism 5 not only ensures the efficient crystallization of the salt, but also achieves a double improvement in the purity and recovery rate of the crystallized salt through precise temperature control and turbulence.

[0044] Furthermore, the crystallization and salt separation mechanism 6 includes a spiral filter press 61, a vibrating screen 62, a salt outlet hopper 63, a filtrate pipe 64 and a salt separation box 65. The spiral filter press 61 is connected to the double-layer coil crystallization tank 51, the spiral filter press 61 is connected to the salt outlet hopper 63, the salt outlet hopper 63 is connected to the vibrating screen 62, and the vibrating screen 62 is connected to the salt separation box 65.

[0045] By adopting the above technical solution, the spiral filter press 61 can perform preliminary squeezing and dehydration on the crystallized salt precipitated in the double-layer coil crystallization tank 51 to remove excess water and impurities. The squeezed crystallized salt enters the salt outlet hopper 63 through the outlet of the spiral filter press 61. The design of the salt outlet hopper 63 ensures that the crystallized salt can flow smoothly into the subsequent vibration screener 62. The vibration screener 62 further screens and grades the crystallized salt through vibration, removes fine particles and impurities therein, and obtains relatively pure crystallized salt. Finally, the screened crystallized salt enters the salt separation box 65 through the outlet of the vibration screener 62, thereby achieving effective separation and recovery of the crystallized salt.

[0046] Working principle of the present invention: The liquid level stabilizing component 110 monitors and controls the liquid level of the buffer tank 11 in real time through the magnetic pole repulsion transmission of the float 1106, the guide rod 1107, the limit ring 1108 and the electromagnetic block, combined with the conductive feedback of the upper and lower limit liquid level probes 1102. The one-way micro-pressure breathing valve 1109 balances the air pressure in the tank, and cooperates with the micro-flow holes 11051 of the buffer cover 1105 to slow down the liquid level fluctuations and ensure the stability of the liquid input before the complexation reaction. The stirring component 19 adopts the hinged design of the screw rod 192 and the universal coupling 193. The electromagnetic block drives the moving block 196 to slide, driving the transmission bevel gear 197 to realize the rotation and revolution of the stirring rod 191, thereby improving the mixing uniformity; the step-by-step precipitation mechanism 3 links the drug pump 33 through the pH probe 32, accurately adds acidic / alkaline agents, and adjusts the pH value in stages to gradually precipitate heavy metal ions. The overflow pipe 37 realizes automatic segmented overflow of the liquid level, and the compression elastic member 44 of the rotary drum filter 41 ensures that the scraper 45 is fitted, and the scraper shaft 46 rotates to scrape off the sediment. The separated slag is discharged through the discharge valve 36, and the liquid is recycled through the reflux pipe 42 to avoid secondary pollution; the double-layer coil crystallization tank 51 uses the temperature difference between the upper and lower layers of high-temperature steam and cooling water to form a temperature gradient for salt precipitation; the polytetrafluoroethylene ball 532 of the spoiler 53 enhances the solution turbulence and improves the crystal purity. After the spiral filter press 61 squeezes and dehydrates the crystallized salt, the vibration screener 62 screens salt particles of different particle sizes through high-frequency vibration, and finally collects them in the salt separation box 65 to achieve efficient recovery of salts.

[0047] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A separation device for stepwise precipitation of heavy metals to recover crystalline salts, characterized in that: The separation device includes a liquid inlet buffer and dispensing mechanism (1), a complexation reaction mechanism (2), a stepwise precipitation mechanism (3), a sediment separation mechanism (4), a crystal salt precipitation mechanism (5) and a crystal salt separation mechanism (6). The liquid inlet buffer and dispensing mechanism (1) is connected to the complexation reaction mechanism (2), the stepwise precipitation mechanism (3) is connected to the complexation reaction mechanism (2), the sediment separation mechanism (4) is connected to the stepwise precipitation mechanism (3), the stepwise precipitation mechanism (3) is connected to the crystal salt precipitation mechanism (5), and the crystal salt separation mechanism (6) is connected to the crystal salt precipitation mechanism (5).

2. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 1, wherein: The liquid inlet buffer and dispensing mechanism (1) includes a buffer tank (11), a liquid inlet pipe (12), a connecting pipe (13), an adjusting pipe (14), a pH pump (15), a liquid inlet valve (16), a pH sensor (17), a connecting valve (18), a stirring assembly (19) and a liquid level stabilizing assembly (110). The buffer tank (11) is connected to the liquid inlet pipe (12), the buffer tank (11) is connected to the adjusting pipe (14), the buffer tank (11) is connected to the connecting pipe (13), the connecting pipe (13) is connected to the connecting valve (18), the connecting valve (18) is connected to the complexation reaction mechanism (2), the pH pump (15) is connected to the adjusting pipe (14), the liquid inlet pipe (12) is connected to the liquid inlet valve (16), the stirring assembly (19) is fixedly connected to the buffer tank (11), the liquid level stabilizing assembly (110) is fixedly connected to the buffer tank (11), the pH sensor (17) is fixedly connected to the buffer tank (11). The pH pump (15) is used to initially adjust the pH value of the stock solution, the connecting valve (18) is used to control the flow rate into the complexation reaction mechanism (2), and the liquid inlet valve (16) is used to control the flow rate of the stock solution into the buffer tank (11).

3. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 2, wherein: The liquid level stabilizing assembly (110) includes an upper limit liquid level probe (1101), a lower limit liquid level probe (1102), a first elastic member (1103), a first electromagnetic block (1104), a buffer cover (1105), a float (1106), a guide rod (1107), a limit ring (1108), and a one-way micro-pressure breathing valve (1109). The buffer cover (1105) is fixedly connected to the buffer tank (11). There are an even number of the limit rings (1108) and the first electromagnetic blocks (1104). Each group of the limit rings (1108) and the first electromagnetic blocks (1104) has two. One limit ring (1108) and one first electromagnetic block (1104) are provided at each of the upper and lower ends of the buffer tank (11). The upper limit liquid level probe (1101) is fixedly connected to the limit ring (1108). The lower limit liquid level probe (1102) is fixedly connected to the limit ring (1108). The guide rod (1107) is fixedly connected to the buffer cover (1105). The buffer cover (1105) is fixedly connected to the buffer tank (11). The buffer cover (1105) is provided with a micro-guide hole (11051) for the slow entry of liquid to reduce the liquid level fluctuation. The limit ring (1108) is slidably connected to the guide rod (1107). The limit ring (1108) is used to control the displacement range of the float (1106) so as to correspond to the upper and lower limit thresholds of the liquid level. The upper limit liquid level probe (1101) and the lower limit liquid level probe (1102) are upper and lower conductive electrodes. The float (1106) is slidably connected to the guide rod (1107). The one-way micro-pressure breathing valve (1109) is communicated with the buffer tank (11). The one-way micro-pressure breathing valve (1109) is located above the buffer tank (11). The first electromagnetic block (1104) is fixedly connected to the buffer cover (1105). The first elastic member (1103) is fixedly connected to the first electromagnetic block (1104). The first elastic member (1103) is fixedly connected to the limit ring (1108). The first electromagnetic block (1104) and the limit ring (1108) are driven by magnetic repulsion.

4. A separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 3, characterized in that: The stirring assembly (19) includes a stirring rod (191), a spiral rod (192), a universal coupling (193), a hinge block (194), a stirring motor (195), a moving block (196), a transmission bevel gear (197), a second electromagnetic block (198), a third electromagnetic block (199), and a second elastic member (1910). The stirring motor (195) is fixedly connected to the buffer tank (11). The stirring motor (195) is in transmission connection with the stirring rod (191). The moving block (196) is fixedly connected to the third electromagnetic block (199). The second elastic member (1910) is fixedly connected to the second electromagnetic block (198). The second elastic member (1910) is fixedly connected to the moving block (196). The second electromagnetic block (198) and the moving block (196) are attracted to each other magnetically for transmission. The third electromagnetic block (199) and the moving block (196) are attracted to each other magnetically for transmission. The moving block (196) is slidably connected to the stirring rod (191). The moving block (196) is in transmission connection with the transmission bevel gear (197). The transmission bevel gear (197) is slidably connected to the third electromagnetic block (199). The transmission bevel gear (197) is slidably connected to the stirring rod (191). The transmission bevel gear (197) is in transmission connection with the universal coupling (193). The universal coupling (193) is hinged to the spiral rod (192). The spiral rod (192) is hinged to the hinge block (194).

5. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 4, wherein: The complex reaction mechanism (2) includes a complex motor (21), a complex tank (22), a first stirrer (23), a liquid storage barrel (24), a metering pump (25), a circulation pump (26), a circulation pipe (27), a heating box (28), a cooling box (29), and a vibration assembly (210). The complex motor (21) is fixedly connected to the complex tank (22). The complex motor (21) is in transmission connection with the first stirrer (23). The liquid storage barrel (24) is communicated with the metering pump (25). The metering pump (25) is communicated with the complex tank (22). The complex tank (22) is communicated with the communication valve (18). The circulation pipe (27) is communicated with the cooling box (29). The circulation pump (26) is communicated with the heating box (28). The heating box (28) is communicated with the circulation pump (26). The circulation pump (26) is communicated with the cooling box (29). The circulation pipe (27) surrounds the inside of the complex tank (22). The vibration assembly (210) includes an eccentric wheel (2101), a vibration block (2102), and a vibration frame (2103). The vibration block (2102) is slidably connected to the vibration frame (2103). The eccentric wheel (2101) is in transmission connection with the vibration block (2102). The first stirrer (23) is in transmission connection with the eccentric wheel (2101).

6. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 5, characterized in that: The stepwise precipitation mechanism (3) includes a precipitation tank (31), a pH probe (32), a chemical pump (33), an acidic chemical barrel (34), a basic chemical barrel (35), a discharge valve (36) and an overflow pipe (37). The precipitation tank (31) is communicated with the overflow pipe (37). The overflow pipe (37) is used for automatically overflowing to the next precipitation section when the liquid level reaches a set height. The chemical pump (33) is communicated with the precipitation tank (31). Both the acidic chemical barrel (34) and the basic chemical barrel (35) are communicated with the chemical pump (33). The precipitation tank (31) is communicated with the discharge valve (36). The discharge valve (36) is located at the bottom of the precipitation tank (31), and the discharge valve (36) is communicated with the sediment separation mechanism (4).

7. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 6, characterized in that: The sediment separation mechanism (4) includes a drum filter (41), a reflux pipe (42), a slag scraping motor (43), a pressing elastic member (44), a scraper (45) and a scraping shaft (46). The slag scraping motor (43) is fixedly connected to the drum filter (41). The slag scraping motor (43) is drivingly connected to the scraping shaft (46). The scraping shaft (46) is fixedly connected to the pressing elastic member (44). The pressing elastic member (44) is fixedly connected to the scraper (45). The scraping shaft (46) is drivingly connected to the scraper (45). The reflux pipe (42) is communicated with the precipitation tank (31). The drum filter (41) is communicated with the discharge valve (36).

8. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 7, characterized in that: The crystal salt precipitation mechanism (5) includes a double-layer coil crystallization tank (51), a temperature probe (52) and a turbulence plate (53). A guide groove (531) is provided on the turbulence plate (53), and a polytetrafluoroethylene ball (532) is embedded in the guide groove (531). The temperature probe (52) is fixedly connected to the double-layer coil crystallization tank (51). The turbulence plate (53) is fixedly connected to the double-layer coil crystallization tank (51). The upper layer of the double-layer coil crystallization tank (51) is for conveying high-temperature steam, and the bottom layer of the upper layer of the double-layer coil crystallization tank (51) is for conveying cooling water.

9. The separation device for stepwise precipitation of heavy metal recovery crystalline salts according to claim 8, wherein: The crystal salt separation mechanism (6) includes a screw filter press (61), a vibrating sieve (62), a salt outlet hopper (63), a filtrate pipe (64) and a salt separation box (65). The screw filter press (61) is communicated with the double-layer coil crystallization tank (51). The screw filter press (61) is communicated with the salt outlet hopper (63). The salt outlet hopper (63) is communicated with the vibrating sieve (62). The vibrating sieve (62) is communicated with the salt separation box (65).

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