Waste acid purification system

Abstract

The utility model relates to the technical field of acid regeneration, in particular to a waste acid purification system which comprises a heating heat exchanger, a leaching tower, a cooling heat exchanger, a reaction tank, a mixing tank, a settling tank and a filter press which are connected in sequence, the leaching tower is connected with an air compression device; the leaching tower is connected with the filter press, and a waste acid solution containing acid mud in the leaching tower is conveyed to the filter press. According to the utility model, the leaching tower is connected with the filter press, and the air compression device is adopted to loosen acid mud in the leaching tower, so that waste acid liquid containing the acid mud in the leaching tower is conveyed to the filter press, and the acid mud is filtered out regularly, thereby not only improving the quality of purified waste acid generated by acid regeneration, stabilizing the quality of a byproduct iron oxide red generated by acid regeneration, but also reducing the production cost. And the acid regeneration does not need to stop for a long time to clean acid mud in the leaching tower, so that the acid regeneration can be stably operated, the operation of the pickling main line is not influenced, and the acid regeneration efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of acid regeneration, in particular to a waste acid purification system. Background Art

[0002] Spent hydrochloric acid regeneration is the process of regenerating spent pickling acid. This process produces regenerated acid for recycling in the pickling line. Red iron oxide, a byproduct of the spray roasting process, is a crucial raw material for the magnetic materials industry. To obtain high-quality red iron oxide, the spent hydrochloric acid must be purified to remove harmful impurities. This is the only way to produce high-quality red iron oxide as a byproduct during the regeneration process.

[0003] At present, ANDRITZ's waste acid purification process is generally used in the hydrochloric acid regeneration industry. The waste acid from pickling is heated and reacted with crushed steel bars to remove most of the free hydrochloric acid, then cooled, neutralized with ammonia water, oxidized with air, and precipitated with flocculants to remove impurities. After purification, the waste acid is deacidified and regenerated for the next production step. Because during the production process, the waste acid and scrap steel bars react in the leaching tower, a lot of solid impurities will be deposited in the leaching tower after long-term operation, affecting the desiliconization effect and reducing the quality of the purified waste acid, thereby affecting the product quality of the acid regeneration by-product red iron oxide and reducing the quality grade of red iron oxide. The leaching tower needs to be cleaned regularly to ensure normal production. With a production capacity of 8m 3 / h acid regeneration system as an example, the diameter of the leaching tower The scrap steel bars in the plant are deposited with acid sludge during operation, making it difficult to clean. Cleaning the plant requires about a month of downtime, affecting the normal production of acid regeneration.

[0004] In view of this, the present utility model is proposed. Utility Model Content

[0005] The utility model aims to provide a waste acid purification system, which does not require shutdown for cleaning of the leaching tower, and has stable quality of the purified waste acid and the quality of the acid regeneration byproduct red iron oxide.

[0006] The utility model provides a waste acid purification system, comprising: a heating heat exchanger, a leaching tower, a cooling heat exchanger, a reaction tank, a mixing tank, a sedimentation tank and a filter press connected in sequence; the leaching tower is connected to an air compression device; the leaching tower is connected to the filter press, and the waste acid liquid containing acid sludge at the bottom of the leaching tower is transported to the filter press.

[0007] Preferably, a first inlet is provided at the top of the leaching tower, and the first inlet is used to add broken edge strips (for example, low-silicon steel strips); a second inlet is provided at the bottom of the leaching tower, and the second inlet is connected to a heating heat exchanger; a first outlet is provided at the upper middle part of the leaching tower, and the first outlet is connected to a cooling heat exchanger; a second outlet is provided at the bottom of the leaching tower, and the second outlet is connected to a filter press; the air compression device is connected to the second inlet and the second outlet respectively through pipelines.

[0008] Preferably, there are two second inlets, which are located on both sides of the second outlet respectively.

[0009] Preferably, the bottom of the leaching tower is a cone, and the second outlet is located at the bottom of the cone.

[0010] Preferably, the second outlet of the leaching tower is connected to the pipeline between the sedimentation tank and the filter press through a pipeline.

[0011] Preferably, the filter press is connected to a waste acid tank, and the waste acid tank is connected to a heating heat exchanger.

[0012] Preferably, the mixing tank is connected to a flocculant storage tank, and the flocculant storage tank is connected to a flocculant dissolution tank.

[0013] Preferably, the reaction tank is connected to an ammonia water tank.

[0014] Preferably, an electromagnetic crane is provided above the leaching tower.

[0015] Preferably, a filter cake bin is provided below the filter press.

[0016] Beneficial effects:

[0017] The utility model utilizes an immersion tower to connect with a filter press, and adopts an air compression device to loosen the acid sludge in the immersion tower, transports the waste acid liquid containing the acid sludge in the immersion tower to the filter press, and regularly filters out the acid sludge, which not only improves the quality of the purified waste acid of acid regeneration and stabilizes the quality of the red iron oxide by-product of acid regeneration, but also does not require long-term shutdown to clean the acid sludge in the immersion tower, so that the acid regeneration can run stably, ensures that the operation of the pickling main line is not affected, and improves the acid regeneration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1This is a structural schematic diagram of the waste acid purification system provided by the utility model.

[0020] Explanation of the accompanying symbols: 1. Soaking tower; 2. Heating heat exchanger; 3. Cooling heat exchanger; 4. Reaction tank; 5. Ammonia water tank; 6. Flocculant dissolution tank; 7. Flocculant storage tank; 8. Mixing tank; 9. Sedimentation tank; 10. Filter press; 11. Electromagnetic crane; 12. Air compression device; 13. Waste acid tank. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0024] Example

[0025] like Figure 1As shown, this embodiment provides a waste acid purification system, comprising: a heating heat exchanger 2, a leaching tower 1, a cooling heat exchanger 3, a reaction tank 4, a mixing tank 8, a sedimentation tank 9 and a filter press 10 connected in sequence; the leaching tower 1 is connected to an air compression device 12; the leaching tower 1 is connected to the filter press 10, and the waste acid liquid containing acid sludge in the leaching tower 1 is transported to the filter press 10.

[0026] In this embodiment, a first inlet is provided at the top of the immersion tower 1, and the first inlet is used to add broken edge strips; a second inlet is provided at the bottom of the immersion tower 1, and the second inlet is connected to the heating heat exchanger 2; a first outlet is provided at the upper middle part of the immersion tower 1, and the first outlet is connected to the cooling heat exchanger 3; a second outlet is provided at the bottom of the immersion tower 1, and the second outlet is connected to the filter press 10; the air compression device 12 is connected to the second inlet and the second outlet respectively through pipelines.

[0027] In this embodiment, there are two second inlets, which are located on both sides of the second outlet respectively.

[0028] In this embodiment, the bottom of the leaching tower 1 is a cone, and the second outlet is located at the bottom of the cone.

[0029] In this embodiment, the second outlet of the leaching tower 1 is connected to the pipeline between the sedimentation tank 9 and the filter press 10 through a pipeline.

[0030] In this embodiment, the filter press 10 is connected to the waste acid tank 13 , and the waste acid tank 13 is connected to the heating heat exchanger 2 .

[0031] In this embodiment, the mixing tank 8 is connected to the flocculant storage tank 7 , and the flocculant storage tank 7 is connected to the flocculant dissolving tank 6 .

[0032] In this embodiment, the reaction tank 4 is connected to the ammonia water tank 5 .

[0033] In this embodiment, an electromagnetic crane 11 is provided above the leaching tower 1 .

[0034] In this embodiment, a filter cake bin is provided below the filter press 10 .

[0035] The working process of this utility model is as follows:

[0036] Waste acid from waste acid tank 13 is first heated to approximately 80°C in heat exchanger 2 before entering leaching tower 1. Shredded edge strips are added to leaching tower 1 via electromagnetic crane 11 to neutralize the free acid in the waste acid. The waste acid leaving leaching tower 1 is cooled to below 45°C in cooling heat exchanger 3 before entering reaction tank 4. Ammonia is added to reaction tank 4 from ammonia tank 5 to adjust the pH of the waste acid to between 4 and 4.5, generating some Fe(OH)₂. Compressed air is introduced from the bottom of reaction tank 4 to partially oxidize the generated Fe(OH)₂ into Fe(OH)₃ colloids, which then adsorb silicon and other impurities in the waste acid. The waste acid exits reaction tank 4 and mixes with flocculant added to the pipeline (the flocculant is prepared in flocculant dissolution tank 6, then stored in flocculant storage tank 7 and delivered to the pipeline by a metering pump in proportion to the amount of waste acid). The mixture then enters mixing tank 8, forming flocs, which then enter settling tank 9 for sedimentation and separation. The supernatant overflows into the waste acid purification tank, and the sludge at the bottom is pumped to the filter press 10 by the slurry pump. The filtrate of the filter press 10 returns to the sedimentation tank 9, and the generated desiliconized filter cake is collected in the filter cake bin and then discharged by vehicle for treatment.

[0037] When it is necessary to clean the acid sludge at the bottom of the leaching tower 1, first turn off the heating heat exchanger 2 to allow the waste acid to self-circulate and cool down. When the liquid temperature of the leaching tower 1 drops below 60°C, turn on the air compression device 12 to loosen the acid sludge at the bottom of the leaching tower 1. Then turn on the filter press 10, and the waste acid liquid containing the acid sludge at the bottom of the leaching tower 1 is transported to the filter press 10. The filtrate returns to the waste acid tank 13, and the waste acid purification process is repeated. The filter cake and the desiliconization filter cake are discharged together. When the filter press 10 runs until there is no filter cake, it stops running. The waste acid purification system of the utility model regularly filters out the acid sludge, and there is no need to regularly shut down the leaching tower 1 for cleaning. The quality of the purified waste acid is stable, and the quality of the acid regeneration byproduct red iron oxide is stable at a first-class product and no longer fluctuates.

[0038] Handan Iron and Steel West District 8m 3 Before 2021, the acid regeneration system required annual shutdown and cleaning of the leaching tower. The waste acid purification system of this embodiment was implemented in 2021, and the leaching tower has not been cleaned of sludge since its operation. After more than three years, the acid regeneration system has been operating well, and the quality of the acid-regenerated red iron oxide has remained stable at first-class quality, with no quality issues caused by leaching tower operation problems.

[0039] Comparative Example

[0040] This comparative example analyzes the waste acid purification production operation process of the existing ANDRITZ waste acid purification system. The results show that as the operating time of the leaching tower increases, the quality of red iron oxide decreases from grade one to grade two after 6-9 months of operation. The results are shown in Table 1.

[0041] Table 1

[0042]

[0043] In summary, the utility model utilizes the leaching tower to connect with the filter press, and adopts the air compression device to loosen the acid sludge in the leaching tower, transports the waste acid liquid containing the acid sludge in the leaching tower to the filter press, and regularly filters out the acid sludge, which not only improves the quality of the purified waste acid of acid regeneration and stabilizes the quality of the by-product red iron oxide of acid regeneration, but also does not require long-term shutdown to clean the acid sludge in the leaching tower, so that the acid regeneration can operate stably, ensures that it does not affect the operation of the pickling main line, and improves the acid regeneration efficiency.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waste acid purification system, characterized in that: include: A heating heat exchanger (2), a leaching tower (1), a cooling heat exchanger (3), a reaction tank (4), a mixing tank (8), a sedimentation tank (9) and a filter press (10) are connected in sequence; the leaching tower (1) is connected to an air compression device; the leaching tower (1) is connected to the filter press (10), and the waste acid liquid containing acid sludge at the bottom of the leaching tower (1) is transported to the filter press (10).

2. The waste acid purification system according to claim 1, characterized in that: The top of the leaching tower (1) is provided with a first inlet, and the first inlet is used to add broken edge strips; the bottom of the leaching tower (1) is provided with a second inlet, and the second inlet is connected to the heating heat exchanger (2); the upper middle part of the leaching tower (1) is provided with a first outlet, and the first outlet is connected to the cooling heat exchanger (3); the bottom of the leaching tower (1) is provided with a second outlet, and the second outlet is connected to the filter press (10); the air compression device is connected to the second inlet and the second outlet respectively through pipelines.

3. The waste acid purification system according to claim 2, characterized in that: There are two second inlets, which are respectively located on both sides of the second outlet.

4. The waste acid purification system according to claim 3, characterized in that: The bottom of the leaching tower (1) is a cone, and the second outlet is located at the bottom of the cone.

5. The waste acid purification system according to claim 2, characterized in that: The second outlet of the leaching tower (1) is connected to the pipeline between the sedimentation tank (9) and the filter press (10) through a pipeline.

6. The waste acid purification system according to claim 1, characterized in that: The filter press (10) is connected to a waste acid tank (13), and the waste acid tank (13) is connected to a heating heat exchanger (2).

7. The waste acid purification system according to claim 1, characterized in that: The mixing tank (8) is connected to the flocculant storage tank (7), and the flocculant storage tank (7) is connected to the flocculant dissolving tank (6).

8. The waste acid purification system according to claim 1, characterized in that: The reaction tank (4) is connected to the ammonia water tank (5).

9. The waste acid purification system according to claim 1, characterized in that: An electromagnetic crane (11) is provided above the leaching tower (1).

10. The waste acid purification system according to claim 1, characterized in that: A filter cake bin is provided below the filter press (10).

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