Device for adjusting pH value of waste acid in settling tank of acid regeneration desilicication system

Abstract

The utility model relates to the technical field of acid regeneration desiliconization, in particular to a device for adjusting the pH value of waste acid in a settling tank of an acid regeneration desiliconization system, which comprises a dissolving tank, a reaction tank, a collecting tank, a settling mechanism and a flocculating agent feeding mechanism, the flocculating agent feeding mechanism is arranged on a pipeline between the reaction tank and the sedimentation mechanism; an inlet of the collecting tank is communicated with a purified acid liquid outlet of the settling mechanism, and an outlet of the collecting tank is communicated with the reaction tank and the acid regeneration pipeline through an acid circulating pipeline. The device can adjust the pH value change of the settling tank acid liquor caused by long-time shutdown to a normal value, so that the quality of the purified waste acid and the quality of the iron oxide powder are ensured, and the economic loss caused by the quality degradation of the iron oxide powder is avoided.

Description

Technical Field

[0001] This utility model relates to the field of acid regeneration and desilication technology, and in particular to a device for adjusting the pH value of waste acid in the settling tank of an acid regeneration and desilication system. Background Technology

[0002] In the steel production process, the treatment of waste acid generated from pickling lines is a crucial step, especially the recovery and reuse of iron oxide powder from the waste acid. To improve the quality of the iron oxide powder, acid regeneration systems are typically equipped with desiliconization systems to effectively remove silicon and other impurities from the waste acid.

[0003] The traditional desilication system process is as follows: Waste acid is first heated to approximately 80°C via a heat exchanger and then enters a dissolving tank. Inside the dissolving tank, scrap metal is added via an electromagnetic crane to neutralize free acid in the waste acid. After preliminary neutralization, the waste acid is then cooled to below 45°C via a graphite cooler and enters a reaction tank. In the reaction tank, ammonia is added to adjust the pH of the waste acid to between 4 and 4.5, at which point some Fe... 2+ The waste acid is converted into Fe(OH)2, and then some of the Fe(OH)2 is oxidized into Fe(OH)3 colloid by passing compressed air through it. Fe(OH)3 colloid has a strong adsorption capacity and can adsorb silicon and other impurities in the waste acid.

[0004] Waste acid treated in the reaction tank is mixed with flocculant to form flocs. The mixed waste acid enters the settling tank for sedimentation and separation. The supernatant overflows into the purified waste acid tank, while the sludge at the bottom is pumped to the filter press. The filtrate from the filter press can be returned to the settling tank or enter the purified waste acid tank, while the generated sludge cake is collected in the filter cake bin and finally discharged by vehicle.

[0005] However, existing desilication systems face some problems in actual operation. Especially when the system is shut down for extended periods (e.g., more than two days), the pH value of the acid solution in the settling tank drops significantly due to the hydrolysis of iron salts. The hydrolysis reaction equations are FeCl2 + 2H2O = Fe(OH)2 + 2HCl and FeCl3 + 3H2O = Fe(OH)3 + 3HCl. This decrease in pH value causes partial dissolution of the already flocculated and precipitated silica sludge (mainly composed of Fe(OH)3), releasing it back into the waste acid, resulting in turbidity and an increased silicon content in the waste acid.

[0006] Because the settling tank has a large volume (e.g., 8m³), 3 For a desilication system with a processing capacity of / h, the settling tank volume is typically 150-200m³. 3When the system restarts, the contaminated waste acid takes 1-2 days to be replaced by fresh waste acid. During this period, the silicon content of the produced iron oxide powder will be severely excessive, and silicon content is a major factor affecting the selling price of iron oxide powder. Therefore, each shutdown results in an economic loss of 30,000-50,000 yuan due to the decline in iron powder quality, placing a significant economic burden on the company.

[0007] In view of this, the present invention is proposed. Utility Model Content

[0008] The purpose of this invention is to provide a pH adjustment device for waste acid in the settling tank of an acid regeneration desilication system. This device can adjust the pH value of the acid solution in the settling tank to the normal value due to long-term shutdown, thereby ensuring the quality of purified waste acid and iron oxide powder, and avoiding economic losses caused by the degradation of iron oxide powder quality.

[0009] This invention provides a device for adjusting the pH value of waste acid in the settling tank of an acid regeneration desilication system, comprising a dissolving tank, a reaction tank, a collecting tank, a settling mechanism, and a flocculant dispensing mechanism.

[0010] The dissolving tank, the reaction tank, and the sedimentation mechanism are connected in sequence, and the flocculant dispensing mechanism is installed on the pipeline between the reaction tank and the sedimentation mechanism.

[0011] The inlet of the collection tank is connected to the purified acid outlet of the settling mechanism, and the outlet of the collection tank is connected to the reaction tank and the acid regeneration pipeline through an acid circulation pipeline.

[0012] As a preferred embodiment of this technical solution, a pH meter is installed on the outlet pipeline of the reaction vessel.

[0013] As a preferred embodiment of this technical solution, the collection tank is equipped with a level gauge.

[0014] As a preferred embodiment of this technical solution, along the reflux direction of the waste acid in the collection tank, the acid circulation pipeline is sequentially equipped with a first valve, a liquid supply pump, and a second valve.

[0015] As a preferred embodiment of this technical solution, the settling mechanism includes a settling tank and a filter press, the bottom of the settling tank is connected to the filter press, and a mud pump is installed on the connecting pipe;

[0016] The dissolving tank, the reaction tank, and the settling tank are connected in sequence, and the flocculant dispensing mechanism is installed on the pipeline between the reaction tank and the settling tank.

[0017] As a preferred embodiment of this technical solution, the flocculant dispensing mechanism includes a flocculant preparation tank and a flocculant storage tank. The flocculant preparation tank is connected to the flocculant storage tank, and the flocculant storage tank is connected to the pipeline between the reaction tank and the settling tank. A metering pump is installed on the connected pipeline.

[0018] As a preferred embodiment of this technical solution, the reaction tank is equipped with an ammonia dosing device.

[0019] As a preferred embodiment of this technical solution, it further includes a cooler, which is installed on the pipeline between the dissolving tank and the reaction tank, and a third valve is provided at the outlet of the cooler.

[0020] As a preferred embodiment of this technical solution, it further includes a waste acid storage tank, which is connected to the dissolving tank, and a heater is installed on the connecting pipe.

[0021] As a preferred embodiment of this technical solution, an electromagnetic crane is provided above the dissolving tank.

[0022] The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system of this utility model has at least the following beneficial effects:

[0023] The present invention relates to a pH adjustment device for waste acid in a settling tank of an acid regeneration desilication system, comprising a dissolving tank, a reaction tank, a collecting tank, a settling mechanism, and a flocculant dispensing mechanism. The dissolving tank, the reaction tank, and the settling mechanism are connected in sequence, and the flocculant dispensing mechanism is located on a pipeline between the reaction tank and the settling mechanism. The inlet of the collecting tank is connected to the purified acid outlet of the settling mechanism, and the outlet of the collecting tank is connected to the reaction tank and the acid regeneration pipeline through an acid circulation pipeline. When preparing for production after the desilication system has been shut down, ensure that the dissolving tank and the reaction tank are connected, the valve between the collection tank and the reaction tank is closed, and the valve connecting the collection tank to the acid regeneration pipeline is closed. Then, start the desilication system and inject waste acid into the dissolving tank. Collect the acid overflowing from the settling tank into the collection tank. Once the set level is reached, stop injecting waste acid into the dissolving tank. At the same time, close the valve between the dissolving tank and the reaction tank, and open the valve between the collection tank and the reaction tank. Then, pump the waste acid from the collection tank to the reaction tank for circulation. When the pH value of the waste acid entering the settling tank is lower than 4.0, inject a certain amount of ammonia into the reaction tank until the pH value of the waste acid returns to the normal value of about 4.0. Add flocculant to the waste acid until the color of the supernatant overflowing from the settling tank becomes clear and transparent. At this point, the quality of the purified acid has returned to normal. Close the valve between the collection tank and the reaction tank, and open the valve between the dissolving tank and the reaction tank, as well as the valve connecting the collection tank to the acid regeneration pipeline. Once everything is back to normal, inject acid into the dissolving tank, and the desilication system can resume normal production. Therefore, the pH adjustment device for waste acid in the settling tank of this acid regeneration desilication system can adjust the pH value of the acid solution in the settling tank to the normal value due to the long-term shutdown, thereby ensuring the quality of purified waste acid and iron oxide powder, and effectively avoiding economic losses caused by the degradation of iron oxide powder quality. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the waste acid pH adjustment device in the settling tank of the acid regeneration and desilication system of this utility model.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1: Dissolving tank; 2: Reaction tank; 3: Collection tank; 4: Acid circulation pipeline; 5: Acid regeneration pipeline; 6: pH meter; 7: First valve; 8: Liquid supply pump; 9: Second valve; 10: Settling tank; 11: Filter press; 12: Slurry pump; 13: Flocculant preparation tank; 14: Flocculant storage tank; 15: Metering pump; 16: Ammonia dosing device; 17: Cooler; 18: Third valve; 19: Waste acid storage tank; 20: Heater; 21: Electromagnetic crane. Detailed Implementation

[0028] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] Example 1

[0032] As shown in the figure, this embodiment provides a waste acid pH adjustment device for a sedimentation tank in an acid regeneration desilication system, including a dissolving tank 1, a reaction tank 2, a collection tank 3, a sedimentation mechanism, and a flocculant dispensing mechanism. The dissolving tank 1, the reaction tank 2, and the sedimentation mechanism are connected in sequence. The flocculant dispensing mechanism is installed on the pipeline between the reaction tank 2 and the sedimentation mechanism. The inlet of the collection tank 3 is connected to the purified acid outlet of the sedimentation mechanism, and the outlet of the collection tank 3 is connected to the reaction tank 2 and the acid regeneration pipeline 5 through an acid circulation pipeline 4.

[0033] In the pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system, when preparing for production after the desilication system has been shut down, first ensure that the dissolving tank 1 and the reaction tank 2 are connected, the valve between the collecting tank 3 and the reaction tank 2 is closed, and the valve of the collecting tank 3 that supplies acid to the acid regeneration pipeline 5 is closed. Then, start the desilication system and inject waste acid into the dissolving tank 1. Collect the acid overflowing from the settling tank 10 into the collecting tank 3. Once the set liquid level is reached, stop injecting waste acid into the dissolving tank 1, and simultaneously close the valve between the dissolving tank 1 and the reaction tank 2. Open the valve between the collecting tank 3 and the reaction tank 2, and then drain the waste acid from the collecting tank 3. The acid is circulated to reaction tank 2. When the pH value of the waste acid entering settling tank 10 is lower than 4.0, a certain amount of ammonia water is injected into reaction tank 2 until the pH value of the waste acid returns to the normal value of about 4.0. Flocculant is added to the waste acid until the color of the supernatant overflowing from settling tank 10 becomes clear and transparent. At this time, the quality of the purified acid solution is restored to normal. Then, the valve between collection tank 3 and reaction tank 2 is closed, the valve between dissolving tank 1 and reaction tank 2 is opened, as well as the valve of collection tank 3 that supplies acid solution to acid regeneration pipeline 5. After everything returns to normal, acid is injected into the dissolving tank, and the desilication system can start normal production.

[0034] The acid regeneration and desilication system in this embodiment can adjust the pH value of the acid solution in the settling tank 10 to the normal value due to the change caused by long-term shutdown. This effectively avoids the problem of the pH value of the acid solution in the settling tank 10 decreasing due to the hydrolysis of iron salts during long-term shutdown (main maintenance or accident), which causes partial dissolution of the flocculated and precipitated silica mud (mainly Fe(OH)3), thereby contaminating the waste acid, making the waste acid turbid, and increasing the silicon content in the acid solution. This device fundamentally ensures the quality of the purified waste acid and the quality of the iron oxide powder, avoiding economic losses caused by the degradation of the iron oxide powder quality.

[0035] Based on the above technical solution, a pH meter 6 is further installed on the outlet pipeline of the reaction tank 2, which is mainly used to monitor the pH value of the waste acid entering the settling tank 10 from the reaction tank 2 online. When the pH value is lower than 4.0, the operator injects a certain amount of ammonia into the reaction tank 2 until the pH value of the waste acid returns to the normal value of about 4.0.

[0036] Based on the above technical solution, and further preferably, the collection tank 3 is equipped with a level gauge to monitor the amount of purified waste acid collected in the collection tank 3 in real time. When the amount of purified waste acid in the collection tank 3 reaches the set level, the injection of waste acid into the dissolving tank 1 must be stopped.

[0037] In this embodiment, specifically, along the reflux direction of the waste acid in the collection tank 3, the acid circulation pipeline 4 is sequentially equipped with a first valve 7, a liquid supply pump 8, and a second valve 9. The first valve 7 is mainly used to control whether the purified waste acid in the collection tank 3 is discharged into the acid regeneration pipeline 5 and the reaction tank 2, and the second valve 9 is mainly used to control whether the purified waste acid in the collection tank 3 enters the reaction tank 2.

[0038] In this embodiment, the settling mechanism specifically includes a settling tank 10 and a filter press 11. The bottom of the settling tank 10 is connected to the filter press 11, and a mud pump 12 is installed on the connecting pipe. The waste acid treated by the reaction tank 2 is mixed with flocculant to form flocs, which then enter the settling tank 10 for sedimentation and separation. The supernatant produced by the settling tank 10 overflows to the collection tank 3, while the sludge at the bottom is pumped to the filter press 11 by the mud pump 12. The filtrate produced in the filter press 11 is further returned to the settling tank 10 or the collection tank 3. The generated mud cake is first collected in the filter cake bin and then discharged by a vehicle.

[0039] When the settling mechanism specifically includes a settling tank 10 and a filter press 11, the dissolving tank 1, the reaction tank 2 and the settling tank 10 are connected in sequence, and the flocculant dosing mechanism is set on the pipeline between the reaction tank 2 and the settling tank 10.

[0040] In this embodiment, the flocculant dispensing mechanism specifically includes a flocculant preparation tank 13 and a flocculant storage tank 14. The flocculant preparation tank 13 and the flocculant storage tank 14 are connected. The flocculant is mainly prepared by the flocculant preparation tank 13, while the flocculant storage tank 14 is mainly used to store the prepared flocculant. Furthermore, the flocculant storage tank 14 is connected to the reaction tank 2 and the settling tank 10 by a pipeline, and a metering pump 15 is installed on the connected pipeline. Specifically, according to the amount of waste acid and the pH value of the waste acid, the metering pump 15 delivers flocculant into the pipeline in proportion to ensure that the impurities in the waste acid are fully flocculated.

[0041] Based on the above technical solution, and more preferably, the reaction tank 2 is equipped with an ammonia water dosing component 16, which can add ammonia water to the reaction tank 2 in real time to adjust the pH value of the waste acid to between 4 and 4.5.

[0042] More preferably, based on the above technical solution, a cooler 17 is also included. The cooler 17 is installed on the pipeline between the dissolving tank 1 and the reaction tank 2, and a third valve 18 is provided at the outlet of the cooler 17. Because the temperature of the waste acid after treatment in the dissolving tank 1 is around 80°C, the cooler 17 is needed to cool the waste acid before it enters the reaction tank 2.

[0043] This utility model does not strictly limit the specific form of the cooler 17, and a graphite cooler 17 can be used.

[0044] Based on the above technical solution, more preferably, it also includes a waste acid storage tank 19, which is connected to the dissolving tank 1, and a heater 20 is installed on the connecting pipe to heat the waste acid in the waste acid storage tank 19 to about 80°C before it is fed into the dissolving tank 1. The heater 20 here can be a heat exchanger.

[0045] More preferably, based on the above technical solution, an electromagnetic crane 21 is provided above the dissolving tank 1, through which scrap strips can be added into the dissolving tank 1 to neutralize the free acid in the waste acid.

[0046] 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 device for adjusting the pH value of waste acid in the settling tank of an acid regeneration desilication system, characterized in that, It includes a dissolving tank (1), a reaction tank (2), a collection tank (3), a sedimentation mechanism, and a flocculant dosing mechanism. The dissolving tank (1), the reaction tank (2), and the settling mechanism are connected in sequence, and the flocculant dispensing mechanism is installed on the pipeline between the reaction tank (2) and the settling mechanism. The inlet of the collection tank (3) is connected to the purified acid outlet of the sedimentation mechanism, and the outlet of the collection tank (3) is connected to the reaction tank (2) and the acid regeneration pipeline (5) through the acid circulation pipeline (4).

2. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, A pH meter (6) is installed on the outlet pipeline of the reaction vessel (2).

3. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, The collection tank (3) is equipped with a level gauge.

4. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, Along the reflux direction of the waste acid in the collection tank (3), the acid circulation pipeline (4) is sequentially equipped with a first valve (7), a liquid supply pump (8), and a second valve (9).

5. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, The settling mechanism includes a settling tank (10) and a filter press (11). The bottom of the settling tank (10) is connected to the filter press (11), and a mud pump (12) is installed on the connecting pipe. The dissolving tank (1), the reaction tank (2), and the settling tank (10) are connected in sequence, and the flocculant dispensing mechanism is installed on the pipeline between the reaction tank (2) and the settling tank (10).

6. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 5, characterized in that, The flocculant dispensing mechanism includes a flocculant preparation tank (13) and a flocculant storage tank (14). The flocculant preparation tank (13) is connected to the flocculant storage tank (14). The flocculant storage tank (14) is connected to the reaction tank (2) and the settling tank (10) via a pipeline. A metering pump (15) is installed on the connected pipeline.

7. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, The reaction vessel (2) is equipped with an ammonia dosing device (16).

8. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, It also includes a cooler (17), which is installed on the pipeline between the dissolving tank (1) and the reaction tank (2), and a third valve (18) is provided at the outlet of the cooler (17).

9. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, It also includes a waste acid storage tank (19), which is connected to the dissolving tank (1), and a heater (20) is installed on the connecting pipe.

10. The pH adjustment device for waste acid in the settling tank of the acid regeneration desilication system according to claim 1, characterized in that, An electromagnetic crane (21) is installed above the melting tank (1).

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