Waste acid desilicication system

Abstract

The utility model relates to the technical field of acid regeneration desiliconization, in particular to a waste acid desiliconization system which comprises a heat exchanger, a dissolving tank, a cooler, a reaction tank, a surface filter and a purified waste acid collecting tank which are connected in sequence, the surface filter is connected with a mixing tank, the top of the mixing tank is connected with a flocculant storage tank through a metering pump, and the bottom of the mixing tank is connected with a sludge collecting tank. According to the utility model, the reaction tank and the surface filter are alternately circulated for desiliconization, so that the desiliconization efficiency is high; the surface filter is high in filtering precision, adjustable, small in equipment size and free of site limitation, multi-stage filtering can be flexibly set according to conditions, and the requirements for iron oxide powder of different quality grades are better met; a sedimentation tank does not need to be built, and the occupied area and economic investment are reduced; a flocculating agent can be proportionally added into the mixing tank according to the sludge amount, so that the use amount of the flocculating agent is greatly reduced, and the device has a wide application prospect.

Description

Technical Field

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

[0002] At present, the pickling medium of steel mainly adopts hydrochloric acid, and the waste acid after pickling mainly adopts the spray roasting process, and finally obtains the regenerated acid and iron oxide powder. The desiliconized iron oxide powder is the main raw material for producing soft magnetism and has a high economic value. Therefore, steel mills with conditions generally have a desiliconization system when building acid regeneration. In addition, if the pickled steel has a high silicon content (more than 0.15%), in order to obtain high-quality iron oxide powder, a pre-desiliconization system is generally added before the desiliconization system to achieve effective removal of silicon. With the increasingly fierce competition in the steel market, in order to adapt to market demand, various steel mills continue to develop new steel grades, improve steel performance by adding various elements, and meet the personalized needs of customers, especially high-strength steel accounts for an increasing proportion. Changes in the composition of steel cause changes in the composition of waste acid, especially high-strength steel generally contains a high silicon content, and the corresponding waste acid silicon content increases. If the original system has only a primary desiliconization system, it is limited by the desiliconization capacity, and iron oxide powder is often downgraded due to excessive silicon, which brings great economic losses to the enterprise. To solve this problem, the traditional method is to add a pre-desiliconization system before the desiliconization system, which requires a large site (sometimes not possible due to site restrictions) and a high economic investment. Traditional desiliconization processes all have sedimentation tanks for sedimentation and separation after adding flocculants to the acid solution. In order to improve the separation efficiency, the sedimentation tank is very large, which increases the floor space and construction costs.

[0003] In view of this, the present utility model is proposed. Utility Model Content

[0004] The utility model aims to provide a waste acid desiliconization system, which has high desiliconization efficiency and does not require the construction of a sedimentation tank, thereby reducing floor space and economic investment, better meeting the demand for iron oxide powder of different quality levels, and having broad application prospects.

[0005] The first aspect of the utility model provides a waste acid desiliconization system, comprising: a heat exchanger, a dissolution tank, a cooler, a reaction tank, a surface filter and a purified waste acid collection tank connected in sequence; the surface filter is connected to a mixing tank, the top of the mixing tank is connected to a flocculant storage tank via a metering pump, and the bottom of the mixing tank is connected to a sludge collection tank.

[0006] In the utility model, the filtering accuracy of the surface filter can be adjusted by replacing the filter membrane, and multi-stage filtration can be flexibly set according to the situation. Under the premise of meeting the desiliconization capacity, the filtering accuracy is adjusted by replacing the filter membrane of the surface filter to meet the requirements of desiliconization efficiency; if a group of filtering devices (reaction tank and surface filter) cannot meet the production capacity and desiliconization efficiency at the same time, the number of filtering devices can be increased depending on the situation.

[0007] Specifically, there is no limit to the number of reaction tanks and surface filters, which can be set according to actual needs, for example: 1, 2, 4 or even more.

[0008] In a specific embodiment, the reaction tank includes: a first reaction tank and a second reaction tank; the surface filter includes: a first surface filter and a second surface filter; the cooler, the first reaction tank, the first surface filter, the second reaction tank, the second surface filter and the purified waste acid collection tank are connected in sequence; the first surface filter and the second surface filter are respectively connected to a mixing tank.

[0009] Preferably, the sludge collection tank is connected to a filter press via a sludge pump, and the filter press is connected to a purified waste acid collection tank.

[0010] Preferably, a filter cake bin is provided below the filter press.

[0011] Preferably, the flocculant storage tank is connected to the flocculant preparation tank.

[0012] Preferably, an electromagnetic crane is provided above the dissolving tank.

[0013] Preferably, the purified waste acid collection tank is connected to the acid regeneration system via an acid pump.

[0014] Preferably, the mixing tank is provided with an agitator and a liquid level detection device.

[0015] Preferably, the sludge collection tank is provided with a liquid level detection device.

[0016] Preferably, the cooler is a graphite cooler.

[0017] A second aspect of the present invention provides a method for desiliconization of waste acid, comprising the following steps:

[0018] S1. Heating, neutralizing and cooling the waste acid;

[0019] S2. The cooled waste acid enters the reaction tank for adsorption desiliconization, and then enters the surface filter for filtration desiliconization. The adsorption desiliconization and filtration desiliconization are alternately cycled for several times;

[0020] S3, the filtered waste acid enters the purified waste acid collection tank, and the sludge produced by filtration enters the mixing tank;

[0021] S4. According to the amount of sludge in the mixing tank, add flocculant in proportion through a metering pump, stir and mix, and then discharge the sludge into the sludge collection tank.

[0022] Preferably, step S1 comprises:

[0023] S11, the waste acid enters the heat exchanger for heating to 70-90°C (preferably 80°C);

[0024] S12, the heated waste acid enters the dissolving tank, and broken edge strips (for example, low silicon steel strips) are added into the dissolving tank through an electromagnetic crane to neutralize the free acid in the waste acid;

[0025] S13, the waste acid after neutralization of the free acid enters the cooler for cooling to below 45°C.

[0026] Specifically, the adsorption desiliconization includes: the cooled waste acid enters a reaction tank, ammonia water is added into the reaction tank to adjust the pH value of the waste acid to between 4 and 4.5, and Fe(OH) 2 , compressed air is introduced from the bottom of the reaction tank to generate Fe(OH) 2 Oxidized to Fe(OH) 3 , using Fe(OH) 3 The colloid absorbs silicon and other impurities in the spent acid.

[0027] Preferably, the surface filter has a self-cleaning function and can clean the sludge deposited on the surface of the filter membrane regularly according to a set time.

[0028] Specifically, the filtration desiliconization includes: the waste acid after adsorption desiliconization enters the surface filter to filter out siliconization and other impurities, and the surface filter automatically cleans the sludge precipitated on the surface of the filter membrane at a regular time.

[0029] Specifically, in step S2, there is no limit to the number of times that adsorption desiliconization and filtration desiliconization are alternately cycled, and it can be set according to actual needs, for example: 1 time, 2 times, 4 times or even more times.

[0030] In a specific embodiment, step S2 includes:

[0031] S21, the cooled waste acid enters the first reaction tank for adsorption desiliconization;

[0032] S22, the waste acid after adsorption and desiliconization enters the first surface filter for filtration and desiliconization;

[0033] S23, filtering the desiliconized waste acid and entering the second reaction tank for adsorption desiliconization;

[0034] S24, the waste acid after adsorption and desiliconization enters the second surface filter for filtration and desiliconization.

[0035] Preferably, step S3 comprises: the filtered waste acid enters the purified waste acid collection tank and enters the acid regeneration system for treatment through an acid pump; and the sludge discharged from the surface filter after filtration enters the mixing tank.

[0036] Preferably, step S4 includes: when the sludge in the mixing tank reaches a certain liquid level, the agitator is started, and flocculant (preferably 15-20ppm of the sludge) is added in proportion through a metering pump according to the amount of sludge in the mixing tank. After stirring and mixing for a certain period of time, the sludge is discharged to the sludge collection tank through the bottom drain valve. When the liquid level in the mixing tank drops to the set value, the addition of flocculant is stopped, the stirring is stopped, and the bottom drain valve is closed.

[0037] Preferably, the method further comprises the following steps:

[0038] S5. When the sludge in the sludge collection tank reaches a certain liquid level, the filter press is turned on, and the filtrate after filtration is discharged into the purified waste acid collection tank, and the filter cake is discharged into the filter cake bin.

[0039] Beneficial effects:

[0040] (1) The surface filter used in the utility model can adjust the filtration accuracy by replacing the filter membrane, which is convenient for timely adjustment of the desiliconization process to better meet production needs.

[0041] (2) The surface filter used in the utility model has high filtering accuracy and small equipment size, is not restricted by the site, and can flexibly set up multi-stage filtering according to the situation to better meet the needs of iron oxide powder of different quality levels.

[0042] (3) The mixing tank of the utility model can add flocculants in proportion to the amount of sludge, which greatly reduces the amount of flocculants used compared to the existing system.

[0043] (4) The utility model adopts the reaction tank and the surface filter to alternately cycle for desiliconization, which has high desiliconization efficiency and does not require the construction of a sedimentation tank, thereby reducing the floor space and economic investment, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] 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 creative work.

[0045] Figure 1 This is a schematic diagram of the structure of a waste acid desiliconization system provided in an embodiment of the utility model.

[0046] Figure 2 This is a schematic diagram of the structure of a waste acid desiliconization system provided as a comparative example of the utility model.

[0047] Explanation of the reference numerals: 1. dissolving tank; 2. heater; 3. cooler; 4. first reaction tank; 5. first surface filter; 6. second reaction tank; 7. second surface filter; 8. metering pump; 9. flocculant preparation tank; 10. flocculant storage tank; 11. mixing tank; 12. sludge collection tank; 13. mud pump; 14. filter press; 15. purified waste acid collection tank; 16. acid pump; 17. electromagnetic crane; 18. broken edge strips; 19. filter cake bin; 20. sedimentation tank. DETAILED DESCRIPTION

[0048] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] 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" and the like 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.

[0050] 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 technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the 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 indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0051] Example

[0052] like Figure 1 As shown, this embodiment provides a waste acid desiliconization system, including: a heat exchanger 2, a dissolving tank 1, a cooler 3, a reaction tank, a surface filter and a purified waste acid collection tank 15 connected in sequence; the surface filter can adjust the filtration accuracy by replacing the filter membrane, so as to facilitate timely adjustment of the desiliconization process and better meet the production needs, and the surface filter has high filtration accuracy and small size, is not restricted by the site, and can flexibly set up multi-stage filtration according to the situation to better meet the needs of iron oxide powder of different quality levels; the reaction tank and the surface filter are used for alternating circulation for desiliconization, the desiliconization efficiency is high, and there is no need to build a sedimentation tank, which reduces the floor space and economic investment, and has broad application prospects; the surface filter is connected to the mixing tank 11, and the top of the mixing tank 11 is connected to the flocculant storage tank 10 through the metering pump 8, the mixing tank 11 can add flocculants in proportion to the amount of sludge, which greatly reduces the use of flocculants, and the bottom of the mixing tank 11 is connected to the sludge collection tank 12.

[0053] In this embodiment, the reaction tank includes: a first reaction tank 4 and a second reaction tank 6; the surface filter includes: a first surface filter 5 and a second surface filter 7; the cooler 3, the first reaction tank 4, the first surface filter 5, the second reaction tank 6, the second surface filter 7 and the purified waste acid collection tank 15 are connected in sequence; the first surface filter 5 and the second surface filter 7 are respectively connected to the mixing tank 11.

[0054] In this embodiment, the sludge collection tank 12 is connected to the filter press 14 via a sludge pump 13 , and the filter press 14 is connected to the purified waste acid collection tank 15 .

[0055] In this embodiment, a filter cake bin 19 is disposed below the filter press 14 .

[0056] In this embodiment, the flocculant storage tank 10 is connected to the flocculant preparation tank 9 .

[0057] In this embodiment, an electromagnetic hanger 17 is arranged above the dissolving tank 1 .

[0058] In this embodiment, the purified waste acid collection tank 15 is connected to the acid regeneration system via an acid pump 16 .

[0059] In this embodiment, the mixing tank 11 is provided with an agitator and a liquid level detection device.

[0060] In this embodiment, the sludge collecting tank 12 is provided with a liquid level detection device.

[0061] In this embodiment, the cooler 3 is a graphite cooler.

[0062] This embodiment also provides a waste acid desiliconization method, comprising the following steps:

[0063] S1. Heating, neutralizing and cooling the waste acid;

[0064] In this embodiment, step S1 includes:

[0065] S11, the waste acid from the pickling line enters the heat exchanger 2 for heating to 80°C;

[0066] S12, the heated waste acid enters the dissolution tank 1, and the broken edge strips 18 are added into the dissolution tank 1 through the electromagnetic crane 17 to neutralize the free acid in the waste acid;

[0067] S13, the waste acid after neutralization of the free acid enters the graphite cooler 3 for cooling to below 45°C.

[0068] S2. The cooled waste acid enters the reaction tank for adsorption desiliconization, and then enters the surface filter for filtration desiliconization. The adsorption desiliconization and filtration desiliconization are alternately cycled for several times;

[0069] Adsorption desiliconization includes: the cooled waste acid enters the reaction tank, ammonia water is added to the reaction tank to adjust the pH value of the waste acid to between 4.2-4.5, and Fe(OH) 2 , compressed air (aeration volume 70-80) is introduced from the bottom of the reaction tank to generate Fe(OH) 2 Oxidized to Fe(OH) 3 , using Fe(OH) 3 The colloid absorbs silicon and other impurities in the spent acid.

[0070] Filtration desiliconization includes: the waste acid after adsorption desiliconization enters the surface filter for filtering and removing silicon and other impurities, and the surface filter automatically cleans the sludge precipitated on the surface of the filter membrane at a regular time.

[0071] Specifically, step S2 includes:

[0072] S21, the cooled waste acid enters the first reaction tank 4 for adsorption desiliconization;

[0073] S22, the waste acid after adsorption and desiliconization enters the first surface filter 5 for filtration and desiliconization;

[0074] S23, filtering the desiliconized waste acid and entering the second reaction tank 6 for adsorption desiliconization;

[0075] S24, the waste acid after adsorption and desiliconization enters the second surface filter 7 for filtration and desiliconization.

[0076] S3, the filtered waste acid enters the purified waste acid collection tank 15, and the sludge produced by the filtration enters the mixing tank 11;

[0077] Specifically, step S3 includes: the filtered waste acid enters the purified waste acid collection tank 15 and enters the acid regeneration system for treatment through the acid pump 16; the sludge discharged from the first surface filter 5 and the second surface filter 7 after self-cleaning is collected in the mixing tank 11.

[0078] S4. According to the amount of sludge in the mixing tank 11, flocculant is added in proportion through the metering pump 8, and after stirring and mixing, the sludge is discharged to the sludge collection tank 12.

[0079] Specifically, step S4 includes: when the sludge in the mixing tank 11 reaches a certain liquid level, the agitator in the mixing tank 11 is started, and in order to facilitate the filtering and separation of the sludge by the filter press, flocculant is added in proportion through the metering pump 8 according to the amount of sludge in the mixing tank 11 (the added amount is 15-20ppm of the sludge), which greatly reduces the use of flocculant. After stirring and mixing for a certain period of time, the sludge is discharged to the sludge collection tank 12 through the bottom drain valve. When the liquid level in the mixing tank 11 drops to the set value, stop adding flocculant, stop stirring, close the bottom drain valve, and enter the next cycle.

[0080] In this embodiment, the following steps are also included:

[0081] S5. When the sludge in the sludge collecting tank 12 reaches a certain liquid level, an alarm is sounded to prompt the operator to start the filter press 14 to drain the sludge. The filtrate after filtration is discharged into the purified waste acid collecting tank 15, and the filter cake is discharged into the filter cake bin 19.

[0082] After testing, the waste acid solution Fe 2+ Concentration 144.5g / L, SiO 2 The average content is 156.5 mg / L. After being treated by the first reaction tank 4 and the first surface filter 5, the filtrate Fe 2+ Concentration 131.8g / L, SiO 2 The average content is 43.5 mg / L, and the desiliconization efficiency is 70%. After being treated by the second reaction tank 6 and the second surface filter 7, the desiliconization efficiency can reach more than 90%.

[0083] Comparative Example

[0084] like Figure 2 As shown, this comparative example provides a waste acid desiliconization system and desiliconization method, comprising the following steps: the waste acid from the pickling line is first heated to about 80°C by a heat exchanger 2, and then enters a dissolving tank 1, and a broken edge strip is added to the dissolving tank 1 by an electromagnetic crane 17 to neutralize the free acid in the waste acid. The waste acid leaving the dissolving tank 1 is cooled to below 45°C by a graphite cooler 3, and then enters a reaction tank 4, and ammonia water is added to the reaction tank 4 to adjust the pH value of the waste acid to between 4 and 4.5, and at the same time, part of Fe(OH) is generated. 2 , compressed air is introduced from the bottom of the reaction tank 4 to generate Fe(OH) 2 Partially oxidized to Fe(OH) 3 Colloid, using Fe(OH) 3The colloid absorbs silicon and other impurities in the waste acid. The waste acid leaves the reaction tank 4 and mixes with the flocculant added to the pipeline to form flocs (the flocculant is prepared by the flocculant preparation tank 5, and then stored in the flocculant storage tank 10, and transported to the pipeline in proportion by the metering pump 8 according to the amount of waste acid), and then enters the sedimentation tank 20 for sedimentation separation. The supernatant overflows to the purified waste acid tank, and the sludge at the bottom is pumped to the filter press 14 by the mud pump 13. The filtrate of the filter press 14 returns to the sedimentation tank 20 (or enters the purified waste acid tank), and the generated mud cake is first collected in the filter cake bin 19, and then discharged by vehicles for treatment.

[0085] According to calculation, the waste acid treatment capacity of this comparative example is 8m 3 / h, the volume of the sedimentation tank is 150-200m 3 , the desiliconization efficiency is 80%.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A waste acid desiliconization system, characterized in that: include: A heat exchanger (2), a dissolving tank (1), a cooler (3), a reaction tank, a surface filter and a purified waste acid collection tank (15) are connected in sequence; the surface filter is connected to a mixing tank (11), the top of the mixing tank (11) is connected to a flocculant storage tank (10) via a metering pump (8), and the bottom of the mixing tank (11) is connected to a sludge collection tank (12).

2. The system according to claim 1, characterized in that The reaction tank comprises: a first reaction tank (4) and a second reaction tank (6); the surface filter comprises: a first surface filter (5) and a second surface filter (7); the cooler (3), the first reaction tank (4), the first surface filter (5), the second reaction tank (6), the second surface filter (7) and the purified waste acid collection tank (15) are connected in sequence; the first surface filter (5) and the second surface filter (7) are respectively connected to a mixing tank (11).

3. The system according to claim 1, characterized in that The sludge collection tank (12) is connected to a filter press (14) via a sludge pump (13), and the filter press (14) is connected to a purified waste acid collection tank (15).

4. The system according to claim 3, characterized in that A filter cake bin (19) is provided below the filter press (14).

5. The system according to claim 1, characterized in that The flocculant storage tank (10) is connected to the flocculant preparation tank (9).

6. The system according to claim 1, characterized in that An electromagnetic crane (17) is arranged above the dissolving tank (1).

7. The system according to claim 1, characterized in that The purified waste acid collection tank (15) is connected to the acid regeneration system via an acid pump (16).

8. The system according to claim 1, characterized in that The mixing tank (11) is provided with a stirrer and a liquid level detection device.

9. The system according to claim 1, characterized in that The sludge collection tank (12) is provided with a liquid level detection device.

10. The system according to claim 1, characterized in that The cooler (3) is a graphite cooler.

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