CN217264980U

CN217264980U - Deacidification device of pickling spent acid

Info

Publication number: CN217264980U
Application number: CN202123319987.8U
Authority: CN
Inventors: 金水玉; 俞海英; 付晓靖; 胡鉴耿
Original assignee: Hangzhou Water Treatment Technology Development Center Co Ltd
Current assignee: Hangzhou Water Treatment Technology Development Center Co Ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-08-23
Anticipated expiration: 2031-12-27

Abstract

The utility model belongs to the technical field of the water treatment, concretely relates to deacidification device of pickling spent acid. The electrodialysis membrane stack of the utility model comprises an anode, an anode membrane, an acid-proof cathode membrane, a composite anode membrane, a cathode membrane and a cathode in sequence; the composite anode membrane is formed by directly superposing positively charged ion exchange mesh cloth and an acid-resistant anode membrane together; an anode chamber is formed between the anode electrode and the anode membrane; a dense chamber is formed between the anode film and the acid-resistant cathode film; a fresh chamber is formed between the acid-resistant negative film and the positively charged ion exchange mesh cloth; a cathode chamber is formed between the cathode film and the cathode electrode; the positive charged ion exchange net cloth in the composite positive membrane faces to the fresh room. The utility model has the advantages that the recovery rate of waste acid can be effectively improved, and impurities can be removed by utilizing the operation of filtering property in the recovery process; and the device has relatively low operation cost, is more environment-friendly and does not generate secondary pollutants.

Description

Deacidification device of pickling spent acid

Technical Field

The utility model belongs to the technical field of the water treatment, concretely relates to deacidification device of pickling spent acid.

Background

The waste acid from pickling in steel rolling, stainless steel, steel wire, welding rod, metal surface treatment, electronic element manufacture, etc. and the liquid waste are listed in the national hazardous waste list. According to different chemical components contained in the waste acid, the waste acid from pickling is divided into three types, namely hydrochloric acid pickling waste acid, sulfuric acid pickling waste acid and mixed acid pickling waste acid. Wherein the hydrochloric acid pickling waste acid contains hydrochloric acid, ferrous chloride and the like; the sulfuric acid pickling waste acid contains sulfuric acid, ferrous sulfate and the like; the mixed acid pickling waste acid contains hydrochloric acid, sulfuric acid and corresponding iron salt.

The current situation of the pickling waste acid treatment process is as follows:

1. neutralization process

The neutralization method is the most commonly used acid pickling waste acid disposal method at present, and the commonly used neutralizing agents comprise limestone, soda, sodium hydroxide, fly ash and the like. The lime neutralization and triple effect evaporation treatment process is adopted, limestone is used as a neutralizer to increase the pH value of waste acid, coprecipitation of calcium sulfate and metal hydroxide is formed, and filtrate is evaporated and discharged after reaching standards.

The lime neutralization precipitation method has the advantages of mature and simple process, low salt content of the effluent and better water quality; the method has the defects that the sludge amount is large, metals in the pickling waste acid are difficult to recover, waste salt generated in the evaporation process is difficult to dispose, the generated secondary solid waste is difficult to comprehensively utilize, and secondary pollution is generated to the environment, so that the method is not a good method for disposing the pickling waste acid.

2. Chemical conversion process

The pickling waste acid has wide sources, wherein the pickling waste acid generated in the steel calendering processing, metal surface treatment and heat treatment processing industries mainly comprises hydrochloric acid waste water and sulfuric acid waste water, and impurities in the pickling waste acid mainly comprise Fe2+, Fe3+, and a small amount of other heavy metal ions such as zinc, copper and the like. The direct disposal of the waste acid has high cost and difficulty, and the metal resource in the waste acid cannot be effectively utilized. According to the characteristics of the waste inorganic acid, the waste inorganic acid is used for preparing the flocculant, so that the treatment difficulty of waste acid is reduced, and certain economic benefit can be brought.

The flocculating agent is a polymeric inorganic flocculating agent appearing in the 80 s of the 20 th century, and mainly comprises an aluminum flocculating agent and an iron flocculating agent. The most commonly used aluminum-based flocculants in water treatment are polyaluminum chloride and polyaluminum sulfate. The polyaluminium chloride has the characteristics of high hydrolysis speed, large flocculating constituent density, wide pH value adaptation range, large specific surface area, strong adsorption capacity, low treatment cost and the like, and is widely applied to water treatment.

The raw materials for preparing the polyaluminium chloride mainly comprise aluminium ash, coal gangue, bauxite, kaolin, calcium aluminate mineral powder and the like, and the preparation methods comprise a thermal decomposition method, an electrolysis method, a membrane reactor method, an acid dissolution method and the like, wherein the acid dissolution method is the most commonly used method for producing the polyaluminium chloride at present. The method for synthesizing polyaluminium chloride by using bauxite as raw material and adopting acid dissolution method includes 3 steps of leaching bauxite, regulating basicity and removing insoluble impurity and heavy metal.

3. Crystallization process

The crystallization method mainly comprises a concentration crystallization method and a freezing crystallization method. The concentration crystallization method separates out salt crystals by evaporating acid components; the freezing crystallization method utilizes the characteristic that the solubility of inorganic salt in waste acid is reduced along with the temperature reduction, and salt crystals are separated out by reducing the solubility of metal salt at low temperature, thereby achieving the purpose of separating acid salt. The crystallization method has the advantages that no new acid is consumed in the treatment process, and the recovered acid can be directly used in an acid consumption working section; the disadvantages are more equipment, large investment and high energy consumption. The method has obvious advantages in both environmental benefit and technical feasibility.

4. Spray sintering process

The regeneration of volatile acids such as hydrochloric acid and nitric acid can be realized by a roasting method. The roasting method is to evaporate and pickle waste acid under the high-temperature condition, recover acid through an absorption tower, carry out hydrolytic oxidation reaction on metal ions in the waste acid solution under the high-temperature condition to generate metal oxides, and enter a powder bin through a conveying pipeline at the bottom of the furnace, thereby achieving the purposes of separating heavy metals and recovering acid.

The main equipment of roasting process includes roasting reaction furnace, cyclone separator, preconcentrator, liquid drop separator and washing tower, etc., and its advantages are high regeneration efficiency of acid and high concentration of regenerated acid, and its disadvantages are large investment, high operation cost, difficult maintenance, high technical difficulty, high energy consumption and secondary pollution. Taking the disposal of waste acid containing iron as an example, the regeneration and recovery of acid are realized, but the utilization value of the generated acid-washing ferric oxide is not high. The spray roasting method is generally applied to the regeneration process of waste acid in large-scale steel plants, but is not suitable for the treatment of pickling waste acid.

5. Ion exchange process

Steel processing enterprises can produce a large amount of pickling waste acid, the concentration of heavy metal ions in the waste liquid is high, and the regenerated acid can be recycled in a pickling section as long as the concentration of the heavy metal ions can be reduced. Currently, ion exchange resins are the most common techniques for treating heavy metal wastewater. The ion exchange resin mainly comprises a monomer, a cross-linking agent and an exchange group, and the structure mainly comprises a macromolecular framework, an ion exchange group and 3 parts of pores. The ion exchange resin is classified into a macroporous type resin and a gel type resin according to the pore type. The action mechanism of the macroporous resin is intermolecular van der Waals force, and macromolecular organic substances can be adsorbed; the gel-type resin belongs to a polymer framework, swells when absorbing water, generates a plurality of pores, and can adsorb inorganic ions. The ion exchange resin is a regenerative material and has good adsorption effect on heavy metal ions, so that the gel resin is widely applied to heavy metal wastewater treatment.

6. Bipolar membrane method

The bipolar membrane method is one of membrane separation methods, and is suitable for treating pickling waste acid with high acid concentration. The membrane separation is a high-efficiency treatment process for separating metal ions from acid by utilizing the high selectivity of the membrane to ions, and can fully recover the acid and metal salt. Common membrane technologies include bipolar membrane, microfiltration, ultrafiltration, electrodialysis, diffusion dialysis, ceramic membrane, reverse osmosis, nanofiltration, and the like. The bipolar membrane method has the advantages of simple process, low investment cost, high recovery rate and higher purity of the recovered acid. However, this method is expensive to operate compared to several other membranes, and due to the material problems of the membranes, a phenomenon occurs in which protons penetrate through the anion exchange membrane, thereby affecting the concentration of the recovered acid and the current efficiency.

SUMMERY OF THE UTILITY MODEL

The utility model provides a deacidification device of pickling spent acid to not enough among the prior art.

The utility model discloses a following technical scheme can realize:

the deacidification device for pickling waste acid is characterized in that: deacidifying by adopting an electrodialysis selective desalting mode, and separating acid from metal salt for deacidification. The core component of the deacidification device is an electrodialysis membrane stack, and the membrane stack comprises components such as an anode, an anode membrane, an acid-resistant cathode membrane, a composite anode membrane, a cathode and the like. The composite positive membrane is formed by directly overlapping a positively charged ion exchange mesh cloth and an acid-resistant positive membrane, and the surface of the positively charged ion exchange mesh cloth faces a light chamber when the membrane stack is stacked. The anode electrode is a titanium iridium tantalum plate electrode, the cathode electrode is a copper plate electrode, the acid-resistant cathode film is an AHA cathode film of ASTOM, and the acid-resistant anode film is a CMB anode film of ASTOM.

A positively charged ion exchange screen cloth of a deacidification device for pickling waste acid adopts the processes of base cloth preparation, functional layer introduction, post-treatment and the like.

A base cloth of a positively charged ion exchange mesh cloth of a deacidification device for pickling waste acid is prepared by adopting fluorine modified acrylic resin fiber woven cloth with the thickness of 0.05-0.2 mm as raw material cloth, performing surface activation by adopting an irradiation grafting method, performing styrene-impregnated reaction, and performing polymerization reaction at the high temperature of 110-160 ℃ to form the base cloth.

A positively charged synthesis method of a positively charged ion exchange screen cloth of a deacidification device for pickling waste acid comprises the steps of soaking base cloth into chloromethyl ether, adding 10-100mg/L stannous chloride, reacting at 50-60 ℃ for 10-15 hours, and then soaking into 1.0-15% of trimesamine solution for 1-2 hours to form a positively charged functional group.

A positive-charged ion exchange net cloth of a deacidification device for pickling waste acid is firstly soaked in a 10% sodium hydroxide solution for 2-8 hours and then washed by water for 3-5 times. Then soaking in 3-5% hydrochloric acid solution for 10-15 hr, then soaking in 10-15% methanol solution for 1-2 hr, and finishing the post-treatment.

The deacidification device for the acid-washing waste acid is characterized in that an anode electrode, an anode chamber, an anode membrane, a dense chamber, an acid-resistant cathode membrane, a dilute chamber, a positively charged ion exchange mesh, an acid-resistant anode membrane, a dense chamber, an acid-resistant cathode membrane, a dilute chamber, a positively charged ion exchange mesh, a cathode membrane, a cathode chamber and a cathode electrode are stacked in sequence. Iron-containing waste acid is fed into an inlet of the dilute chamber, residual waste acid is fed into an outlet of the dilute chamber, and recovered acid is fed into an inlet of the concentrated chamber, and water is fed into an outlet of the concentrated chamber.

The operating conditions of the deacidification device for pickling waste acid are as follows: the flow rate of the membrane surface is 0.1-0.5cm/s, the operation temperature is 5-10 ℃, the operation voltage of each pair of membranes is 0.05-0.1V, and the current density is 100- ² 。

Has the advantages that: by the operation of the device, the recovery rate of waste acid can be effectively improved, and impurities can be removed by the operation of filtering property in the recovery process; compared with the traditional recovery method, the device has relatively low operation cost and is more environment-friendly. In the operation process, no chemical agent is added, and no secondary pollutant is generated.

Drawings

Fig. 1 is a schematic structural view of the device of the present invention

1. An anode electrode; 2. an anode chamber; 3. an anodic film; 4. a thickening chamber; 5. acid-resistant negative films; 6. a fade-out chamber; 7. positively charged ion exchange mesh cloth; 8. acid-resistant positive films; 9. a cathode film; 10. a cathode chamber; 11. a cathode electrode; 12. iron-containing waste acid; 13. water; 14. residual waste acid; 15. and (4) recovering the acid.

Detailed Description

The following description will be made in detail with reference to the accompanying fig. 1:

example 1

A deacidification device for pickling waste acid comprises an electrodialysis membrane stack, wherein the electrodialysis membrane stack sequentially comprises an anode electrode 1, an anode membrane 3, an acid-resistant cathode membrane 5, a composite anode membrane, a cathode membrane 9 and a cathode electrode 11; wherein the composite anode membrane is formed by directly superposing a positively charged ion exchange mesh cloth 7 and an acid-resistant anode membrane 8 together; an anode chamber 2 is formed between the anode electrode 1 and the anode membrane 3; a dense chamber 4 is formed between the anode film 3 and the acid-resistant cathode film 5; a dilute chamber 6 is formed between the acid-resistant negative film 5 and the positively charged ion exchange mesh cloth 7; a cathode chamber 10 is formed between the cathode film 9 and the cathode electrode 11; the positively charged ion exchange mesh 7 in the composite positive membrane faces the dilute chamber 6.

The positively charged ion exchange fabric 7 is made of a cloth woven from fluorine-modified acrylic resin fibers with a thickness of 0.1 mm, and is subjected to surface activation by an irradiation grafting method, then to styrene-impregnated reaction, and polymerization reaction at a high temperature of 140 ℃ to form a base cloth. Soaking the base cloth into chloromethyl ether, adding 30mg/L stannous chloride, reacting at 55 ℃ for 12 hours, and then soaking into 2.5 percent of mesitylene trimethylamine solution for 1.5 hours to form a positively charged functional group. The positively charged ion exchange web 7, having formed positively charged functional groups, was first soaked in 10% sodium hydroxide solution for 5 hours and then washed 5 times with water. After soaking in 4% hydrochloric acid solution for 12 hr, 10% methanol solution for 1.5 hr, the post-treatment is completed.

The anode chamber 1, the anode chamber 2, the anode membrane 3, the concentration chamber 4, the acid-resistant cathode membrane 5, the diluting chamber 6, the positively charged ion exchange mesh 7, the acid-resistant anode membrane 8, the concentration chamber 4, the acid-resistant cathode membrane 5, the diluting chamber 6, the positively charged ion exchange mesh 7, the cathode membrane 9, the cathode chamber 10 and the cathode electrode 11 are stacked in sequence. The anode electrode 1 is a titanium-iridium-tantalum plate electrode, the cathode electrode 11 is a copper plate electrode, the acid-resistant cathode film is an AHA cathode film of ASTOM, and the acid-resistant anode film is a CMB anode film of ASTOM. 100 sets of 550 x 1100mm size films were assembled. Waste acid 12 with ferrous sulfate concentration of 25g/L and sulfuric acid concentration of 100g/L is fed into the inlet of the diluting chamber 6, and water is fed into the inlet of the concentrating chamber 4. The treated waste acid 12 is changed into residual waste acid 14 to be discharged, and finally the recovered acid 15 can be discharged and recovered through a pipeline.

The operation conditions were set such that the flow rate on the membrane surface was 0.3cm/s, the operation temperature was 8 ℃, the operation voltage per pair of membranes was 0.05V, and the current density was 150A/m 2. After the treatment process, the recovery rate of the acid can reach 82 percent, and the removal rate of impurities in the recovered acid reaches 95 percent.

Example 2

A deacidification device for pickling waste acid comprises an electrodialysis membrane stack, wherein the electrodialysis membrane stack sequentially comprises an anode electrode 1, an anode membrane 3, an acid-resistant cathode membrane 5, a composite anode membrane, a cathode membrane 9 and a cathode electrode 11; wherein the composite anode membrane is formed by directly superposing a positively charged ion exchange mesh cloth 7 and an acid-resistant anode membrane 8 together; an anode chamber 2 is formed between the anode electrode 1 and the anode membrane 3; a concentration chamber 4 is formed between the anode film 3 and the acid-resistant cathode film 5; a dilute chamber 6 is formed between the acid-resistant negative film 5 and the positively charged ion exchange mesh cloth 7; a cathode chamber 10 is formed between the cathode film 9 and the cathode electrode 11; the positively charged ion exchange mesh 7 of the composite positive membrane faces the fade chamber 6. The method comprises the steps of spinning fluorine modified acrylic resin fiber with the thickness of 0.2 mm into cloth as a raw material cloth, activating the surface by adopting an irradiation grafting method, carrying out styrene-impregnated reaction, and carrying out polymerization reaction at the high temperature of 130 ℃ to form the base cloth. Soaking the base cloth into chloromethyl ether, adding 30mg/L stannous chloride, reacting at 58 ℃ for 15 hours, and then soaking into 3% of mesitylene trimethylamine solution for 2 hours to form a positively charged functional group. The positively charged ion exchange web 7, having formed positively charged functional groups, was first soaked in 10% sodium hydroxide solution for 6 hours and then washed 5 times with water. And then soaking in a 5% hydrochloric acid solution for 15 hours, and then soaking in a 10% methanol solution for 2 hours, so that the post-treatment is completed.

The anode chamber 1, the anode chamber 2, the anode membrane 3, the concentration chamber 4, the acid-resistant cathode membrane 5, the diluting chamber 6, the positively charged ion exchange mesh 7, the acid-resistant anode membrane 8, the concentration chamber 4, the acid-resistant cathode membrane 5, the diluting chamber 6, the positively charged ion exchange mesh 7, the cathode membrane 9, the cathode chamber 10 and the cathode electrode 11 are stacked in sequence. The anode electrode 1 is a titanium-iridium-tantalum plate electrode, the cathode electrode 11 is a copper plate electrode, the acid-resistant cathode film is an AHA cathode film of ASTOM, and the acid-resistant anode film is a CMB anode film of ASTOM. 100 sets of 550 x 1100mm size films were assembled. Waste acid 12 with ferrous sulfate concentration of 25g/L and sulfuric acid concentration of 100g/L is fed into an inlet of the diluting chamber 6, and water is fed into an inlet of the concentrating chamber 4.

The operation conditions were set such that the flow rate on the membrane surface was 0.5cm/s, the operation temperature was 10 ℃, the operation voltage per pair of membranes was 0.08V, and the current density was 200A/m 2. After the treatment process, the recovery rate of the acid can reach 85 percent, and the removal rate of impurities in the recovered acid reaches 90 percent.

Example 3

The assembly of the membrane module and all the fittings were the same as in example 2.

Waste acid 12 with ferrous sulfate concentration of 100g/L and sulfuric acid concentration of 150g/L is fed into an inlet of the diluting chamber 6, and water is fed into an inlet of the concentrating chamber 4.

The operation conditions were set such that the flow rate on the membrane surface was 0.3cm/s, the operation temperature was 10 ℃, the operation voltage per pair of membranes was 0.05V, and the current density was 250A/m 2. After the treatment process, the recovery rate of the acid can reach 75 percent, and the removal rate of impurities in the recovered acid reaches 85 percent.

Claims

1. A deacidification device for pickling waste acid comprises an electrodialysis membrane stack, and is characterized in that the electrodialysis membrane stack sequentially comprises an anode (1), an anode membrane (3), an acid-resistant cathode membrane (5), a composite anode membrane, a cathode membrane (9) and a cathode (11);

wherein the composite positive membrane is formed by directly superposing a positively charged ion exchange mesh cloth (7) and an acid-resistant positive membrane (8); an anode chamber (2) is formed between the anode electrode (1) and the anode membrane (3); a concentration chamber (4) is formed between the anode film (3) and the acid-resistant cathode film (5); a fresh chamber (6) is formed between the acid-resistant negative film (5) and the positively charged ion exchange mesh cloth (7); a cathode chamber (10) is formed between the cathode film (9) and the cathode electrode (11);

the positive charged ion exchange net cloth (7) in the composite positive membrane faces the light chamber (6).

2. The deacidification device for pickling waste acid according to claim 1, wherein the anode electrode (1) is a titanium-iridium-tantalum plate electrode, and the cathode electrode (11) is a copper plate electrode.

3. The deacidification apparatus of spent acid from pickling as defined in claim 1, wherein said acid-resistant cathode is AHA cathode available from ASTOM and said acid-resistant anode is CMB anode available from ASTOM.

4. A deacidification apparatus as claimed in claim 1, characterized in that the iron containing spent acid (12) is fed into the inlet of the thin chamber (6), the residual spent acid (14) is fed out from the outlet of the thin chamber (6), and the recovered acid (15) is fed out from the outlet of the thick chamber (4) as water (13).

5. The deacidification plant of spent acid from pickling according to claim 1, wherein the plant operating conditions are: the flow rate of the membrane surface is 0.1-0.5cm/s, the operation temperature is 5-10 ℃, the operation voltage of each pair of membranes is 0.05-0.1V, and the current density is 100- ² 。