A waste sulfuric acid recycling treatment device

Abstract

The application discloses a waste sulfuric acid recycling treatment equipment, and belongs to the field of industrial waste acid treatment. The treatment equipment comprises a pretreatment unit, a core separation unit and a purification storage unit which are sequentially connected through pipelines and pumps. The pretreatment unit comprises a first-stage sedimentation tank and a second-stage precision filter. The core separation unit is a diffusion dialyzer, and the outlet of the second-stage precision filter is connected with the acid chamber inlet of the diffusion dialyzer. The bottom of a water chamber is provided with a recovered acid outlet. The purification storage unit is a recovered acid storage tank, and the inlet of the recovered acid storage tank is connected with the recovered acid outlet. Through the combined process of "two-stage pretreatment + diffusion dialysis + purification storage", the pollution and blockage risk of an anion exchange membrane in the diffusion dialyzer is greatly reduced, the service life of the membrane is prolonged, the sulfuric acid recovery rate is improved, the waste sulfuric acid can be recycled at normal temperature and pressure, the amount of new acid purchase and waste acid discharge is reduced, the subsequent recovery of residual liquid containing metals is facilitated, and the environmental benefits and economic benefits are considered.

Description

Technical Field

[0001] This application relates to the field of industrial waste acid treatment technology, specifically a waste sulfuric acid recycling treatment device. Background Technology

[0002] In the production processes of industries such as metallurgy, electroplating, and chemicals, large quantities of waste sulfuric acid with varying concentrations and containing impurities such as heavy metals are generated. Currently, the main methods for treating waste sulfuric acid include neutralization, high-temperature pyrolysis, extraction, and membrane treatment.

[0003] Neutralization requires a large amount of alkali, generating useless gypsum, resulting in the waste of sulfuric acid resources and secondary pollution; high-temperature pyrolysis consumes a lot of energy and requires large equipment investment; extraction and some membrane methods have complex processes, high operating costs, and membrane modules are prone to fouling and clogging.

[0004] Therefore, this application provides a waste sulfuric acid recycling and treatment device to solve the above problems. Utility Model Content

[0005] This application provides a waste sulfuric acid recycling and treatment device, which aims to solve the problems mentioned in the background art, such as serious resource waste and easy secondary pollution of existing neutralization methods, excessive energy consumption and equipment investment of high-temperature pyrolysis methods, complex process and high operating cost of extraction methods, and membrane treatment methods being limited by membrane fouling and cost.

[0006] To achieve the above objectives, this application provides the following technical solution: a waste sulfuric acid recycling treatment device, comprising a pretreatment unit, a core separation unit, and a purification and storage unit connected sequentially by pipelines and pumps; the pretreatment unit includes a primary sedimentation tank for precipitation and a secondary precision filter connected to the primary sedimentation tank for removing micron-sized particles; the core separation unit is a diffusion dialysis unit, which has an internal anion exchange membrane that divides the internal space of the diffusion dialysis unit into an acid chamber and a water chamber; the outlet of the secondary precision filter is connected to the inlet of the acid chamber of the diffusion dialysis unit, and the bottom of the acid chamber has a residual liquid outlet; the top of the water chamber has a water inlet, and the bottom has a recovered acid outlet; the purification and storage unit is a recovered acid storage tank, and the inlet of the recovered acid storage tank is connected to the recovered acid outlet. The waste sulfuric acid to be treated first undergoes sedimentation in the primary sedimentation tank and filtration in the secondary precision filter of the pretreatment unit to remove large suspended solids and fine impurities. The clarified waste acid after pretreatment enters the acid chamber of the diffusion dialysis unit in the core separation unit. Driven by the concentration difference, sulfate ions pass through the anion exchange membrane and enter the water chamber to form recovered acid. The recovered acid enters the recovered acid storage tank of the purification storage unit. After being detected by an online concentration detector, if it meets the standard, it is reused; if it does not meet the standard, it is returned to the diffusion dialysis unit for further concentration. The metal-containing residual liquid discharged from the acid chamber is collected and treated separately.

[0007] Preferably, the primary sedimentation tank has a waste acid inlet at the top and a clear liquid outlet on the upper side wall. The clear liquid outlet is connected to the inlet of the secondary precision filter via a transfer pump. This provides pre-purified waste acid to the subsequent secondary precision filter, reducing the load on the secondary filtration and improving the overall pretreatment efficiency. At the same time, the transfer pump stably delivers the clear liquid, ensuring continuous operation of the pretreatment process.

[0008] Preferably, the primary sedimentation tank has a first sludge discharge port at its bottom, and the secondary precision filter has a second sludge discharge port at its bottom. Both the first and second sludge discharge ports are connected to a sludge thickening tank. This allows for centralized collection and treatment of sludge generated during the pretreatment process, avoiding indiscriminate discharge of sludge and preventing secondary pollution. It also reduces the space occupied by sludge and lowers the difficulty of subsequent disposal.

[0009] Preferably, to accelerate the settling of solid particles, the primary settling tank is equipped with inclined plate packing. This shortens the settling time of suspended solids in the primary settling tank, improves settling efficiency, increases the amount of waste acid treated per unit time, and ensures efficient operation of the pretreatment process. The clarified liquid outlet is located above the inclined plate packing.

[0010] Preferably, the filter element in the secondary precision filter has a filter element precision of 1-10 micrometers, preferably 5 micrometers. This precisely removes micron-sized fine impurities remaining in the pretreated waste acid, preventing impurities from entering the diffusion dialysis unit and contaminating the anion exchange membrane, thus ensuring the separation efficiency of the core separation unit and the service life of the membrane module.

[0011] Preferably, to enable secondary treatment of acid solutions with substandard concentrations: the outlet of the recovered acid storage tank is connected to a three-way valve, which is connected to both the reuse pipeline and the acid chamber inlet of the diffusion dialysis unit. This secondary treatment of the recovered acid in the storage tank ensures that the final reused sulfuric acid concentration meets production requirements, improves sulfuric acid resource utilization, and prevents substandard acid solutions from affecting the production process.

[0012] Preferably, an online concentration detector is installed on the outlet pipe of the recycled acid storage tank. Real-time monitoring of the recycled acid concentration at the tank outlet provides accurate data for determining whether the recycled acid should be reused or subjected to secondary treatment, preventing substandard acid from entering the production process and ensuring the stability of the production process and product quality.

[0013] Preferably, to prevent external leaves from falling into the primary sedimentation tank, an inclined grid plate is fixedly installed at the waste acid inlet of the primary sedimentation tank. This blocks large debris such as leaves and branches from entering the primary sedimentation tank, preventing debris from clogging the waste acid inlet, affecting the sedimentation effect in the tank, or damaging subsequent conveying pumps and other equipment, thus ensuring the stable operation of the pretreatment unit.

[0014] This application utilizes a combined process of "two-stage pretreatment + diffusion dialysis + purification and storage" to significantly reduce the risk of fouling and clogging of the anion exchange membrane in the diffusion dialysis unit, extend the membrane's service life, improve the sulfuric acid recovery rate, and enable the recycling of waste sulfuric acid at room temperature and pressure. This reduces the amount of new acid purchased and waste acid discharged, while also facilitating the subsequent recovery of metal-containing residual liquids, thus balancing environmental and economic benefits.

[0015] This application uses a grating plate to block large debris such as leaves and branches from the external environment from entering the primary sedimentation tank, thereby preventing debris from clogging the waste acid inlet, affecting the sedimentation effect in the tank, or damaging subsequent transfer pumps and other equipment, and ensuring the stable operation of the pretreatment unit. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 for Figure 1 A sectional view of the structural part.

[0017] In the picture: 1. Pretreatment unit; 11. Primary sedimentation tank; 111. Waste acid inlet; 112. First slag discharge port; 113. Clear liquid outlet; 114. Inclined plate packing; 12. Secondary precision filter; 121. Second slag discharge port; 13. Transfer pump; 2. Core separation unit; 21. Diffusion dialysis unit; 211. Anion exchange membrane; 212. Acid chamber; 2121. Residual liquid outlet; 213. Water chamber; 2131. Recovered acid outlet; 3. Purification and storage unit; 31. Recovered acid storage tank; 311. Three-way valve; 4. Online concentration detector; 5. Grating plate. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Example 1

[0020] A waste sulfuric acid recycling and treatment device, such as Figure 1-2As shown, the processing equipment includes a pretreatment unit 1, a core separation unit 2, and a purification and storage unit 3 connected in sequence by pipes and pumps. The pretreatment unit 1 includes a primary sedimentation tank 11 for precipitation and a secondary precision filter 12 connected to the primary sedimentation tank 11 for removing micron-sized particles. The core separation unit 2 is a diffusion dialysis unit 21, which has an anion exchange membrane 211 inside, dividing the space inside the diffusion dialysis unit 21 into an acid chamber 212 and a water chamber 213. The outlet of the secondary precision filter 12 is connected to the inlet of the acid chamber 212 of the diffusion dialysis unit 21, and the bottom of the acid chamber 212 has a residual liquid outlet 2121. The top of the water chamber 213 has a water inlet, and the bottom has a recovered acid outlet 2131. The purification and storage unit 3 is a recovered acid storage tank 31, and the inlet of the recovered acid storage tank 31 is connected to the recovered acid outlet 2131. By employing a combined process of "two-stage pretreatment + diffusion dialysis + purification and storage," the risk of fouling and clogging of the anion exchange membrane 211 in the diffusion dialysis unit 21 is significantly reduced, extending membrane lifespan, improving sulfuric acid recovery rate, and enabling the recycling of waste sulfuric acid at ambient temperature and pressure. This reduces the amount of new acid purchased and waste acid discharged, while facilitating the subsequent recovery of metal-containing residual liquid, thus balancing environmental and economic benefits. The waste sulfuric acid to be treated first undergoes sedimentation in the primary sedimentation tank 11 and filtration in the secondary precision filter 12 of the pretreatment unit 1 to remove large suspended solids and fine impurities. The clarified waste acid after pretreatment enters the acid chamber 212 of the diffusion dialysis unit 21 in the core separation unit 2. Driven by the concentration difference, sulfate ions pass through the anion exchange membrane 211 and enter the water chamber 213 to form recovered acid. The recovered acid enters the recovered acid storage tank 31 of the purification and storage unit 3. After being detected by the online concentration detector 4, if the concentration meets the standard, it is reused; otherwise, it is returned to the diffusion dialysis unit 21 for further concentration. The metal-containing residual liquid discharged from the acid chamber 212 is collected and treated separately.

[0021] The primary sedimentation tank 11 has a waste acid inlet 111 at the top and a clear liquid outlet 113 on the upper side wall. The clear liquid outlet 113 is connected to the inlet of the secondary precision filter 12 via a transfer pump 13. This provides pre-purified waste acid to the secondary precision filter 12, reducing the load on the secondary filter and improving the overall pretreatment efficiency. Simultaneously, the transfer pump 13 stably delivers the clear liquid, ensuring continuous operation of the pretreatment process. The waste sulfuric acid to be treated enters the tank through the waste acid inlet 111 at the top of the primary sedimentation tank 11. Most of the suspended solids settle in the tank, and the upper layer of clarified waste acid is pumped into the secondary precision filter 12 for further filtration via the clear liquid outlet 113 on the upper side wall and pressurized by the transfer pump 13.

[0022] The primary sedimentation tank 11 has a first sludge discharge port 112 at its bottom, and the secondary precision filter 12 has a second sludge discharge port 121 at its bottom. Both the first and second sludge discharge ports 112 and 121 are connected to a sludge thickening tank. This allows for centralized collection and treatment of sludge generated during the pretreatment process, preventing secondary pollution caused by indiscriminate sludge discharge, reducing the space occupied by sludge, and simplifying subsequent disposal. Suspended solids settling in the primary sedimentation tank 11 are periodically discharged from the first sludge discharge port 112 at the bottom, while fine particles filtered and retained by the secondary precision filter 12 are discharged from the second sludge discharge port 121 at the bottom. The sludge discharged from both is transported through pipelines to the sludge thickening tank for centralized thickening treatment.

[0023] To accelerate the settling of solid particles, the primary sedimentation tank 11 is equipped with inclined plate packing 114, and the clear liquid outlet (113) is located above the inclined plate packing (114). The inclined plate packing 114 can shorten the settling time of suspended solids in the primary sedimentation tank 11, improve the sedimentation efficiency, increase the amount of waste acid treated per unit time, and ensure the efficient operation of the pretreatment process. The inclined plate packing 114 forms multiple inclined sedimentation surfaces in the primary sedimentation tank 11. The suspended solids in the waste sulfuric acid settle to the surface of the inclined plate under the action of gravity. The settled solids slide down the inclined plate to the bottom of the tank. Compared with the structure without inclined plates, the sedimentation area is increased and the sedimentation process is accelerated.

[0024] The secondary precision filter 12 has a filtration accuracy of 5 micrometers. It precisely removes micron-sized fine impurities remaining in the pretreated waste acid, preventing impurities from entering the diffusion dialysis unit 21 and contaminating the anion exchange membrane 211, thus ensuring the separation efficiency of the core separation unit 2 and the service life of the membrane module. The clarified liquid after treatment in the primary sedimentation tank 11 enters the secondary precision filter 12. The filter element inside has a pore size of 5 micrometers, which can trap fine particles and impurities in the clarified liquid with a particle size larger than the corresponding pore size, allowing the clarified waste acid that meets the accuracy requirements to enter the subsequent diffusion dialysis unit 21 through the filter outlet.

[0025] To enable secondary treatment of acid solutions with substandard concentrations, a three-way valve 311 is connected to the outlet of the recovered acid storage tank 31. This valve 311 connects to both the reuse pipeline and the inlet of the acid chamber 212 of the diffusion dialysis unit 21. This secondary treatment of substandard recovered acid in the storage tank 31 ensures that the final reused sulfuric acid concentration meets production requirements, improves sulfuric acid resource utilization, and prevents substandard acid solutions from affecting the production process. After testing, if the recovered acid in the storage tank 31 meets the concentration requirements, the three-way valve 311 switches to the reuse pipeline, and the acid is pumped back to the production workshop. If the concentration is too low, the valve switches to the path connecting to the inlet of the acid chamber 212 of the diffusion dialysis unit 21, sending the substandard acid back to the core separation unit 2 for further diffusion dialysis concentration.

[0026] An online concentration detector 4 is installed on the outlet pipe of the acid recovery storage tank 31. This detector monitors the concentration of the recovered acid at the outlet of the tank in real time, providing accurate data for determining whether the recovered acid should be reused or subjected to secondary treatment. This prevents substandard acid from entering the production process, ensuring the stability of the production process and product quality. The online concentration detector 4 is installed on the outlet pipe of the acid recovery storage tank 31. As the acid flows through the detector, it analyzes the acid concentration in real time using conductivity and transmits the data to the control system. The control system then controls the switching of the three-way valve 311 based on the concentration data.

[0027] In use, the waste sulfuric acid to be treated enters the primary sedimentation tank 11 through the waste acid inlet 111, where most of the suspended solids settle and are periodically discharged through the first slag discharge port 112 at the bottom. The supernatant is sent to the secondary precision filter 12 by the transfer pump 13 through the clear liquid outlet 113 to remove the remaining fine particles. The pretreated clarified waste acid enters the acid chamber 212 of the diffusion dialysis unit 21. At the same time, the counter-flowing dialysis water or dilute acid enters the water chamber 213 through the inlet. Driven by the concentration difference, the free sulfate ions SO4²⁻ in the acid chamber 212 pass through the anion exchange membrane 211 into the water chamber 213 and combine with H⁺ in the water chamber 213 to form sulfuric acid; while the metal ions, due to their positive charge, are blocked by the membrane and remain in the acid chamber 212. Finally, the liquid flowing out of the acid chamber 212 is a residual liquid rich in metal salts, which is discharged and collected from the residual liquid outlet 2121; the liquid flowing out of the water chamber 213 is the recovered pure sulfuric acid solution, which enters the recovered acid storage tank 31. The acid in the acid storage tank 31 is analyzed by the online concentration detector 4. If the concentration meets the standard, it is pumped back to the production workshop through the reuse pipeline. If the concentration is too low, the three-way valve 311 can be switched to send it back to the acid inlet pipeline of the diffusion dialysis unit 21 for further concentration.

[0028] Example 2

[0029] Unlike Embodiment 1, to prevent external leaves from falling into the primary sedimentation tank 11, an inclined grating 5 is fixedly installed at the waste acid inlet 111 of the primary sedimentation tank 11. This prevents large debris such as leaves and branches from entering the primary sedimentation tank 11, avoiding blockage of the waste acid inlet 111, affecting the sedimentation effect in the tank, or damaging subsequent equipment such as the transfer pump 13, thus ensuring the stable operation of the pretreatment unit 1. The grating 5 is fixedly inclined at the waste acid inlet 111 of the primary sedimentation tank 11. When waste acid carries external debris into the inlet, the debris is intercepted by the grating 5 and cannot enter the tank. At the same time, the inclined structure facilitates the natural sliding down or manual cleaning of the intercepted debris.

[0030] The control method of this utility model is controlled by a controller. The control method can be implemented by those skilled in the art through simple programming, without creative labor. The circuit connection is also common knowledge in the field. This utility model protects mechanical devices, so the control method and circuit connection will not be explained in detail.

[0031] All electrical components of this invention are electrically connected to the main controller and power supply. The main controller can be a conventional known device such as a computer that provides control.

[0032] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A waste sulfuric acid recycling and treatment device, characterized in that: It includes a pretreatment unit (1), a core separation unit (2), and a purification and storage unit (3) connected in sequence by pipes and pumps. The pretreatment unit (1) includes a primary sedimentation tank (11) for sedimentation and a secondary precision filter (12) connected to the primary sedimentation tank (11) for removing micron-sized particles. The core separation unit (2) is a diffusion dialysis unit (21). The diffusion dialysis unit (21) has an anion exchange membrane (211) built in, which divides the space inside the diffusion dialysis unit (21) into an acid chamber (212) and a water chamber (213). The outlet of the secondary precision filter (12) is connected to the inlet of the acid chamber (212) of the diffusion dialysis unit (21). The bottom of the acid chamber (212) is provided with a residual liquid outlet (2121). The water chamber (213) has an inlet at the top and a recovery acid outlet (2131) at the bottom. The purification storage unit (3) is a recycled acid storage tank (31), and the inlet of the recycled acid storage tank (31) is connected to the recycled acid outlet (2131).

2. The waste sulfuric acid recycling and treatment equipment according to claim 1, characterized in that: The primary sedimentation tank (11) is provided with a waste acid inlet (111) at the top and a clear liquid outlet (113) at the upper part of the side wall. The clear liquid outlet (113) is connected to the inlet of the secondary precision filter (12) through a transfer pump (13).

3. The waste sulfuric acid recycling and treatment equipment according to claim 1, characterized in that: The first-stage sedimentation tank (11) is provided with a first slag discharge port (112) at the bottom, and the second-stage precision filter (12) is provided with a second slag discharge port (121) at the bottom. Both the first slag discharge port (112) and the second slag discharge port (121) are connected to a sludge thickening tank.

4. The waste sulfuric acid recycling and treatment equipment according to claim 2, characterized in that: The primary sedimentation tank (11) is equipped with inclined plate packing (114), and the clear liquid outlet (113) is located above the inclined plate packing (114).

5. The waste sulfuric acid recycling and treatment equipment according to claim 1, characterized in that: The filter element in the secondary precision filter (12) has a precision of 1-10 micrometers.

6. The waste sulfuric acid recycling and treatment equipment according to claim 1, characterized in that: The outlet of the recycled acid storage tank (31) is connected to a three-way valve (311), which is connected to the reuse pipeline and the inlet of the acid chamber (212) of the diffusion dialysis unit (21).

7. The waste sulfuric acid recycling and treatment equipment according to claim 1, characterized in that: An online concentration detector (4) is installed on the outlet pipe of the acid recovery storage tank (31).

8. The waste sulfuric acid recycling and treatment equipment according to any one of claims 1-7, characterized in that: An inclined grid plate (5) is fixedly installed at the waste acid inlet (111) of the primary sedimentation tank (11).

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