Device for recycling sodium chloride from vanadium precipitation wastewater

Abstract

The utility model relates to the technical field of vanadium precipitation wastewater recovery, in particular to a device for recycling sodium chloride from vanadium precipitation wastewater, which comprises a precipitation tank, an evaporator I and an evaporator II, the precipitation tank is used for precipitating impurities in the vanadium precipitation wastewater, the evaporator I is used for evaporating slag-removed waste liquid, and the evaporator II is used for carrying out secondary evaporation on the waste liquid; the settling box is connected with the first evaporator through a first pump body and a liquid conveying pipe, a first steam outlet of the first evaporator is communicated with a first heating cavity of the second evaporator through a gas conveying pipe, the first evaporator is connected with the second evaporator through a second pump body and a liquid conveying pipe, a first heating device is arranged on the first evaporator, and a control box is installed on the settling box. And solid discharge valves are arranged at the bottoms of the settling tank, the evaporator I and the evaporator II. According to the utility model, through staged control, salt separation and energy optimization, the problems of high energy consumption, low purity and scaling of direct evaporation are solved, and meanwhile, the advantage of high-efficiency recovery of resources is realized.

Description

Technical Field

[0001] This utility model relates to the field of vanadium precipitation wastewater recovery technology, specifically a sodium chloride recovery and utilization device for vanadium precipitation wastewater. Background Technology

[0002] Vanadium-containing wastewater refers to the wastewater generated after vanadium is removed through precipitation during vanadium extraction or processing (such as vanadium extraction from vanadium ore, vanadium alloy production, and preparation of vanadium-containing catalysts). Vanadium is toxic to aquatic organisms and humans; long-term exposure may cause respiratory diseases and skin damage. High salinity and high pH levels can disrupt the ecological balance of aquatic bodies and affect soil quality.

[0003] Existing methods for recovering sodium chloride from vanadium-precipitated wastewater commonly employ evaporation crystallization. However, direct evaporation requires heating the entire wastewater to boiling, resulting in extremely high energy consumption (especially for high-salinity wastewater). For example, direct evaporation consumes approximately 60-100 kWh per ton of wastewater, with treatment costs reaching 15-25 yuan per ton. Furthermore, direct evaporation cannot separate different salts; sodium chloride often co-crystallizes with impurities such as ammonium sulfate and vanadates, achieving a purity of only 70%-80%, which fails to meet industrial-grade (≥95%) or food-grade requirements. Valuable components such as ammonium sulfate and vanadates in the wastewater are not separated and are directly mixed with sodium chloride, losing their recovery opportunity. For instance, 1 ton of vanadium-precipitated wastewater contains approximately 15-30 kg of ammonium sulfate; direct evaporation would result in an economic loss of approximately 20-40 yuan per ton.

[0004] Since existing evaporation recovery technologies are not only costly but also produce sodium chloride with low purity, we propose a sodium chloride recovery and utilization device for vanadium precipitation wastewater. Utility Model Content

[0005] The purpose of this invention is to provide a sodium chloride recovery device for vanadium precipitation wastewater. Through staged control, salt separation and energy optimization, it overcomes the problems of high energy consumption, low purity and scaling caused by direct evaporation, while achieving the advantages of efficient resource recovery.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a sodium chloride recycling device for vanadium-precipitated wastewater, comprising a sedimentation tank, an evaporator one, and an evaporator two. By adding vanadium-precipitated wastewater and a precipitating agent to the sedimentation tank, impurities in the vanadium-precipitated wastewater are precipitated. The precipitated wastewater is then fed into the evaporator one, where the slag-removed waste liquid is evaporated. The waste liquid is then further evaporated by the evaporator two.

[0007] The sedimentation tank is connected to evaporator 1 via pump body 1 and a liquid delivery pipe. Pump body 1 pumps the precipitated waste liquid into evaporator 1 to achieve solid-liquid separation. The steam outlet 1 of evaporator 1 is connected to the heating chamber 1 of evaporator 2 via a gas delivery pipe. By setting up heating chamber 1, the steam generated in evaporator 1 can be introduced into heating chamber 1 to heat the waste liquid in evaporator 2, achieving heat recovery and utilization. Evaporator 1 is connected to evaporator 2 via pump body 2 and a liquid delivery pipe. Pump body 2 pumps the evaporated waste liquid from evaporator 1 into evaporator 2 to achieve solid-liquid separation. Evaporator 1 is equipped with heating device 1, which achieves evaporation through heating. A control box is installed on the sedimentation tank. Solid discharge valves are installed at the bottom of the sedimentation tank, evaporator 1, and evaporator 2. All solid discharge valves have a certain inclination angle. The solid discharge valve of the sedimentation tank is used to discharge precipitate, the solid discharge valve of evaporator 1 is used to discharge ammonium sulfate or other preferentially precipitated crystals, and the solid discharge valve at the bottom of evaporator 2 is used to discharge precipitated sodium chloride crystals.

[0008] Preferably, a second heating device is installed on the sedimentation tank, which is used to control the sedimentation temperature. The second heating device is used to control the reaction temperature inside the sedimentation tank to ensure the normal and stable operation of the sedimentation reaction.

[0009] Preferably, the settling tank is equipped with a second heating chamber, which is connected to a second steam outlet via a first steam pipe. An exhaust valve is installed on the second heating chamber. By providing the second heating chamber, the steam generated by the second evaporator can be reused, heat recovered, and energy consumption for temperature control reduced. Furthermore, the steam from both the first and second steam pipes can be directly discharged into the atmosphere.

[0010] Preferably, the steam pipe one is connected to the heating chamber one of the evaporator two via the steam pipe two. This allows the heating chamber two to be connected to the heating chamber one, enabling the steam generated by the evaporator one to first pass through the evaporator two for heat recovery, and then pass through the settling tank for heat recovery.

[0011] Preferably, the evaporator two is equipped with a heating device three. The heating device three can supplement the heating of the evaporator two when the heat recovery is insufficient for evaporation.

[0012] Preferably, the system also includes a precipitant adding mechanism, which is used to add precipitant to the settling tank. The precipitant adding mechanism includes a first precipitant tank and a second precipitant tank. The precipitant adding mechanism separates and recovers vanadium and chromium by adding specific reducing agents and alkaline solutions to the settling tanks, causing vanadium and chromium to precipitate and be recovered. Specifically, reducing agents such as sodium metabisulfite and sodium bisulfite are added to reduce pentavalent vanadium and other metal ions to a lower valence state, and then an alkaline solution is added to cause the metal ions to form hydroxide precipitates that are separated from the wastewater.

[0013] Preferably, the first precipitant tank and the second precipitant tank are connected to the sedimentation tank via an infusion pipe and a third pump body; by providing the third pump body, the reducing agent or alkaline solution in the first precipitant tank and the second precipitant tank can be pumped into the sedimentation tank.

[0014] A flow meter is installed on the infusion pipe of pump body three, a solenoid valve one is installed on the infusion pipe of precipitant tank one, and a solenoid valve two is installed on the infusion pipe of precipitant tank two. By setting two solenoid valves, the infusion pipe of one of the precipitant tanks can be selectively opened, and the amount added can be monitored by the flow meter.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] This invention pre-treats vanadium-containing wastewater in a sedimentation tank to remove impurities such as vanadium and chromium ions, as well as other potentially interfering substances. For example, by adding specific reducing agents and alkaline solutions, vanadium and chromium precipitate and are then separated and recovered. The wastewater is then subjected to evaporation and crystallization in two stages using evaporators one and two. Heating causes the water to evaporate, and as the water content decreases, the sodium chloride concentration gradually increases, reaching saturation and initiating crystallization. Furthermore, the secondary steam generated in the previous evaporator is used as the heat source for the next stage, reducing the steam consumption per ton of water evaporated from approximately 1.1 tons in single-effect evaporation to approximately 0.55 tons in double-effect evaporation, effectively reducing energy costs. This invention solves the problems of high cost and low purity of recovered sodium chloride in existing evaporation recovery technologies. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model.

[0018] Figure 2 This is a schematic diagram of the internal structure of this utility model.

[0019] In the diagram: 1. Sedimentation tank; 2. Evaporator 1; 3. Evaporator 2; 4. Pump body 1; 5. Pump body 2; 6. Heating device 1; 7. Steam outlet 1; 8. Steam outlet 2; 9. Heating chamber 1; 10. Control box; 11. Heating device 2; 12. Heating chamber 2; 13. Steam pipe 1; 14. Steam pipe 2; 15. Exhaust valve; 16. Sediment tank 1; 17. Sediment tank 2; 18. Flow meter; 19. Solenoid valve 1; 20. Solenoid valve 2; 21. Pump body 3; 22. Heating device 3. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figure 1 and 2 As shown, a sodium chloride recycling device for vanadium-precipitated wastewater includes a sedimentation tank 1, an evaporator 1 2, and an evaporator 2 3. By adding vanadium-precipitated wastewater and a precipitant to the sedimentation tank 1, impurities in the vanadium-precipitated wastewater are precipitated. The precipitated wastewater is then fed into the evaporator 1 2, where the slag-removed waste liquid is evaporated. The waste liquid is then further evaporated in the evaporator 2 3.

[0022] Settling tank 1 is connected to evaporator 2 via pump body 4 and a liquid delivery pipe. Pump body 4 pumps the settled waste liquid into evaporator 2 to achieve solid-liquid separation. The steam outlet 7 of evaporator 2 is connected to the heating chamber 9 of evaporator 3 via a gas delivery pipe. By setting up heating chamber 9, steam generated in evaporator 2 can be introduced into heating chamber 9 to heat the waste liquid in evaporator 3, achieving heat recovery and utilization. Evaporator 2 is connected to evaporator 3 via pump body 5 and a liquid delivery pipe. Pump body 5 pumps the evaporated waste liquid from evaporator 2 into evaporator 3 to achieve solid-liquid separation. Evaporator 2 is equipped with heating device 6, which achieves evaporation through heating. A control box 10 is installed on settling tank 1. The control box 10 is used to control the operation of each pump body, heating device, and solenoid valve. The control box 10 specifically uses a PLC controller. Solid discharge valves are installed at the bottom of settling tank 1, evaporator 2, and evaporator 3. All solid discharge valves are equipped with a certain inclination angle. The solid discharge valve of sedimentation tank 1 is used to discharge the precipitate, the solid discharge valve of evaporator 2 is used to discharge ammonium sulfate or other preferentially precipitated crystals, and the solid discharge valve at the bottom of evaporator 3 is used to discharge precipitated sodium chloride crystals. The heating temperature of evaporator 2 is 60-70℃, which preferentially evaporates water and precipitates ammonium sulfate. The heating temperature of evaporator 3 is 90-100℃, and sodium chloride precipitates after the remaining solution is concentrated. At this time, the concentration of calcium and magnesium ions has been significantly reduced.

[0023] A heating device 2 11 is installed on the sedimentation tank 1. The heating device 2 11 is used to control the sedimentation temperature. The heating device 2 11 is used to control the reaction temperature inside the sedimentation tank 1 to ensure the normal and stable operation of the sedimentation reaction.

[0024] A second heating chamber 12 is provided inside the settling tank 1. The second heating chamber 12 is connected to the second steam outlet 8 via a first steam pipe 13. An exhaust valve 15 for discharging steam is provided on the second heating chamber 12. By setting up the second heating chamber 12, the steam generated by the second evaporator 3 can be reused, heat can be recovered, and energy consumption for temperature control can be reduced. Furthermore, the steam from the first steam pipe 13 and the second steam pipe 14 can also be directly discharged into the atmosphere.

[0025] Steam pipe 13 is connected to heating chamber 9 of evaporator 2 3 via steam pipe 2 14. This connects heating chamber 2 12 with heating chamber 9, allowing the steam generated by evaporator 2 to first pass through evaporator 2 3 for heat recovery, and then through sedimentation tank 1 for heat recovery.

[0026] Evaporator 2 3 is equipped with heating device 3 22. Heating device 3 22 can supplement the heating of evaporator 2 3 when the heat recovery is insufficient for evaporation.

[0027] It also includes a precipitant addition mechanism, which adds precipitant to the sedimentation tank 1. The precipitant addition mechanism includes precipitant tank one (16) and precipitant tank two (17). The precipitant addition mechanism separates and recovers vanadium and chromium by adding specific reducing agents and alkaline solutions to the sedimentation tank 1, causing vanadium and chromium to precipitate. Specifically, reducing agents such as sodium metabisulfite and sodium bisulfite are added to reduce pentavalent vanadium and other metal ions to lower valence states, and then alkaline solution is added to cause the metal ions to form hydroxide precipitates that are separated from the wastewater.

[0028] Precipitator tank 16 and precipitator tank 27 are connected to sedimentation tank 1 via infusion pipes and pump body 3 21; by setting pump body 3 21, the reducing agent or alkaline solution in precipitator tank 16 and precipitator tank 27 can be pumped into sedimentation tank 1.

[0029] A flow meter 18 is installed on the infusion pipe of pump body 3 21, a solenoid valve 19 is installed on the infusion pipe of precipitant tank 1 16, and a solenoid valve 20 is installed on the infusion pipe of precipitant tank 2 17. By installing two solenoid valves, the infusion pipe of one of the precipitant tanks can be selectively opened, and the amount added can be monitored by the flow meter 18.

[0030] In operation, vanadium-precipitated wastewater is first added to sedimentation tank 1. Then, one or more reducing agents, such as sodium metabisulfite and sodium bisulfite, from precipitant tank 16 are added to sedimentation tank 1 via the precipitant addition mechanism. This reduces pentavalent vanadium and other metal ions in the vanadium-precipitated wastewater to a lower valence state. Alkali solution is then added to cause the metal ions to form hydroxide precipitates, which are then separated from the wastewater and pumped into evaporator 2. The precipitated wastewater undergoes solid-liquid separation through the delivery pipe of pump body 4. Filter screens are installed on the delivery pipes of pump body 4, pump body 5, and pump body 21. The precipitate in sedimentation tank 1 is discharged and recycled through the solid discharge valve at the bottom.

[0031] Evaporator 2 heats wastewater to 60-70℃ via heating device 6, preferentially evaporating water and precipitating ammonium sulfate. The ammonium sulfate crystals have a purity ≥98%, making it suitable as fertilizer or industrial raw material. Temperature sensors and liquid level sensors are installed in sedimentation tank 1, evaporator 2, and evaporator 3 to monitor temperature changes. Heating devices 6, 11, and 22 all use electric heating plates or other heating methods. Wastewater from evaporator 2 is pumped into evaporator 3 via pump 5, while steam from evaporator 2 is simultaneously introduced into heating chamber 9 of evaporator 3 for a degree of heat recovery. The heating temperature in evaporator 3 is 90-100℃. After the remaining solution is concentrated, sodium chloride precipitates. At this point, the calcium and magnesium ion concentrations are significantly reduced, and the sodium chloride purity is ≥95%, meeting industrial salt standards. Direct evaporation consumes 80-100 kW·h / ton, while staged evaporation consumes 15-25 kW·h / ton.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for recovering sodium chloride from vanadium-precipitated wastewater, characterized in that: It includes a sedimentation tank (1), an evaporator (2) and an evaporator (3). The sedimentation tank (1) is used to precipitate impurities in vanadium-containing wastewater. The evaporator (2) is used to evaporate the waste liquid after slag removal. The evaporator (3) is used to perform secondary evaporation of the waste liquid. The sedimentation tank (1) is connected to the evaporator (2) via a pump body (4) and a liquid delivery pipe. The steam outlet (7) of the evaporator (2) is connected to the heating chamber (9) of the evaporator (3) via a gas delivery pipe. The evaporator (2) is connected to the evaporator (3) via a pump body (5) and a liquid delivery pipe. The evaporator (2) is equipped with a heating device (6). The sedimentation tank (1) is equipped with a control box (10). The sedimentation tank (1), the evaporator (2), and the evaporator (3) are all equipped with solid discharge valves at their bottoms.

2. The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 1, characterized in that: The sedimentation tank (1) is equipped with a second heating device (11), which is used to control the sedimentation temperature. 3.The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 1 or 2, characterized in that: The settling tank (1) is provided with a second heating chamber (12), which is connected to a second steam outlet (8) through a first steam pipe (13). An exhaust valve (15) is provided on the second heating chamber (12).

4. The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 3, characterized in that: The steam pipe 1 (13) is connected to the heating chamber 1 (9) of the evaporator 2 (3) through the steam pipe 2 (14).

5. The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 1, characterized in that: The evaporator 2 (3) is equipped with a heating device 3 (22).

6. The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 1, characterized in that: It also includes a precipitant adding mechanism for adding precipitant to the precipitant tank (1), the precipitant adding mechanism including precipitant tank one (16) and precipitant tank two (17).

7. The device for recovering and utilizing sodium chloride from vanadium precipitation wastewater according to claim 6, characterized in that: The first precipitant tank (16) and the second precipitant tank (17) are connected to the precipitant tank (1) via an infusion pipe and a third pump body (21); A flow meter (18) is installed on the infusion pipe of the pump body three (21), a solenoid valve one (19) is installed on the infusion pipe of the precipitant tank one (16), and a solenoid valve two (20) is installed on the infusion pipe of the precipitant tank two (17).

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