A method for treating hot galvanizing waste slag pickling waste liquid and a preparation method of chloride ion adsorbent

Abstract

The application relates to the technical field of wastewater treatment, and particularly discloses a hot galvanizing waste residue pickling waste liquid treatment method and a preparation method of a chloride ion adsorbent. The hot galvanizing waste residue pickling waste liquid treatment method comprises the following steps: adding the chloride ion adsorbent into waste residue pickling waste liquid with a pH value of 3-4, stirring and mixing to obtain a mixed solution; adding sodium alginate into the mixed solution, stirring and mixing, filtering, adjusting the pH value of the filtrate to 6-7 by using a caustic alkali, and obtaining treated waste residue pickling waste liquid; and the preparation method of the chloride ion adsorbent comprises the following steps: stirring and mixing amino silane coupling agent and water, then adding aluminum magnesium hydrotalcite, stirring and mixing, aging, washing with water, drying, grinding, and obtaining the chloride ion adsorbent. The hot galvanizing waste residue pickling waste liquid treatment method can effectively remove chloride ions and divalent iron ions in the waste residue pickling waste liquid, has high safety, and is suitable for large-scale promotion.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of wastewater treatment, in particular to a hot galvanizing waste residue pickling waste liquid treatment method and a preparation method of a chloride ion adsorbent. BACKGROUND

[0002] Hot galvanizing, also known as hot dipping zinc or hot dipping galvanizing, is an effective metal corrosion prevention method, which mainly adopts hot dipping technology to immerse a steel piece after rust removal into molten zinc at about 500 DEG C, so that a zinc layer is attached to the surface of the steel piece, thereby achieving the purpose of corrosion prevention.

[0003] In the hot galvanizing process, the rust removal process of the plated piece is a key step, and hydrochloric acid is usually used for pickling, so a large amount of pickling waste liquid containing divalent iron is generated after pickling. Domestic enterprises using hot galvanizing technology usually discharge the waste acid and the pickling waste liquid after neutralization by using quicklime. Not only is a neutralization device needed, but also alkaline chemical raw materials for waste acid neutralization treatment need to be purchased to ensure that the acidic wastewater reaches the pH value required by the discharge standard.

[0004] However, neutralizing the waste acid will generate a certain amount of useless waste residue pickling waste liquid, and the main component of the waste residue pickling waste liquid is calcium chloride, and both calcium chloride and ferrous chloride are water-soluble substances, which will inevitably cause a large amount of chloride ion discharge and serious "chlorine poisoning" to the environment. SUMMARY

[0005] In order to improve the removal rate of chloride ions in the waste residue pickling waste liquid, the application provides a hot galvanizing waste residue pickling waste liquid treatment method and a preparation method of a chloride ion adsorbent.

[0006] In a first aspect, the application provides a hot galvanizing waste residue pickling waste liquid treatment method, which adopts the following technical scheme: a hot galvanizing waste residue pickling waste liquid treatment method, comprising the following steps:

[0007] S1: adding a chloride ion adsorbent into waste residue pickling waste liquid with a pH value of 3-4, stirring and mixing to obtain a mixed liquid;

[0008] S2: adding sodium alginate into the mixed liquid, stirring and mixing, filtering, adjusting the pH value of the filtrate to 6-7 by using caustic soda, and obtaining treated waste residue pickling waste liquid;

[0009] The preparation method of the chloride ion adsorbent is: first, stirring and mixing amino silane coupling agent and water, then adding aluminum magnesium hydrotalcite, stirring and mixing, aging, washing with water, drying, and grinding to obtain the chloride ion adsorbent.

[0010] After the pickling waste liquid is treated by using quicklime, a large amount of chloride ions and divalent iron ions are contained in the waste residue pickling waste liquid with a pH value of 3-4.

[0011] The amino silane is hydrolyzed and then condensed to form a polymer, and after aging and other treatments, a gel is formed and adsorbed on the surface of the aluminum magnesium hydrotalcite to obtain a chlorine ion adsorbent containing the amino gel. On the one hand, the gel in the chlorine ion adsorbent has a large number of micropores and a high surface area, and can adsorb a large amount of chlorine ions, effectively reducing the content of chlorine ions in the waste residue pickling waste liquid. On the other hand, in the waste residue pickling waste liquid with a pH value of 3-4, the amino groups in the chlorine ion adsorbent can be ionized to form ammonium ions, and the ammonium ions interact with the chlorine ions to adsorb the chlorine ions in the chlorine ion adsorbent, which is conducive to further improving the removal rate of chlorine ions in the waste residue pickling waste liquid. Then, the filtrate is neutralized by using caustic alkali, and the treated waste residue pickling waste liquid can reach the pH value required by the discharge standard.

[0012] Therefore, the application uses the chlorine ion adsorbent to treat the waste residue pickling waste liquid, which not only reduces the content of chlorine ions in the waste residue pickling waste liquid, but also reduces the amount of caustic alkali used in the neutralization of the filtrate, effectively improving the environmental protection and safety of the hot galvanizing waste residue pickling waste liquid treatment method, and being suitable for large-scale production.

[0013] Preferably, in the preparation method of the chlorine ion adsorbent, the weight ratio of the aluminum magnesium hydrotalcite, the amino silane coupling agent and the water is 1:(0.025-0.055):(3-6).

[0014] By adopting the above technical scheme, the aluminum magnesium hydrotalcite with a layered structure is used as a carrier, and the weight ratio of the amino silane and the aluminum magnesium hydrotalcite is controlled, so that the interlayer ions of the aluminum magnesium hydrotalcite can exchange with the chlorine ions and the divalent iron ions in the waste residue pickling waste liquid, and the removal rates of the chlorine ions and the divalent iron ions in the waste residue pickling waste liquid can be effectively improved.

[0015] Preferably, the amino silane is one or both of 3-aminopropylmethyldimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane.

[0016] By adopting the above technical scheme, the above type of amino silane has a good hydrolysis rate, the formed gel has a large number of active sites, and has a good chlorine ion removal efficiency.

[0017] Preferably, the amino silane is composed of 3-aminopropylmethyldimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane in a weight ratio of 1:(0.45-0.65).

[0018] By adopting the above technical scheme, two kinds of amino silanes are selected to be hydrolyzed and polymerized to form a three-dimensional network structure gel with a dense structure, which has good acid and alkali resistance, and is conducive to improving the application range of the chlorine ion adsorbent in waste residue pickling waste liquids with different pH values.

[0019] Preferably, the preparation method of the chloride ion adsorbent is as follows: firstly, the amino silane coupling agent and water are stirred and mixed, then the aluminum magnesium hydrotalcite and the non-ionic water-soluble cellulose ether are added and stirred and mixed, and then the chloride ion adsorbent is obtained after aging, water washing, drying and grinding.

[0020] The weight ratio of the aluminum magnesium hydrotalcite, the amino silane coupling agent, the water-soluble non-ionic cellulose ether and water is 1:(0.025-0.055):(0.01-0.015):(3-6).

[0021] By adopting the above technical solution, the non-ionic water-soluble cellulose ether has good suspension stability, which can improve the dispersion stability of the obtained chloride ion adsorbent in the waste residue pickling waste liquid, and is beneficial to improving the removal rate of chloride ions and divalent iron ions in the waste residue pickling waste liquid.

[0022] Preferably, the water-soluble non-ionic cellulose ether is methylhydroxyethyl cellulose or hydroxyethyl cellulose.

[0023] Preferably, the hydroxyethyl cellulose has a molar substitution degree of 1.8-2.0, a pH value of 6.0-8.5 and a viscosity of 5-60000 mpa·s.

[0024] By adopting the above technical solution, the methylhydroxyethyl cellulose and the hydroxyethyl cellulose have good water solubility, which is beneficial to the full dispersion of the aluminum magnesium hydrotalcite in the amino silane polymer, so that the aluminum magnesium hydrotalcite surface is uniformly distributed with gel, and is beneficial to improving the adsorption efficiency of the chloride ion adsorbent.

[0025] Preferably, the feeding amount of the chloride ion adsorbent in the waste residue pickling waste liquid with a pH value of 3-4 is 0.6-1.8 g / L.

[0026] By adopting the above technical solution, the chloride ion adsorbent has high chloride ion and divalent iron ion adsorption rate, and a small amount of chloride ion adsorbent can be used to treat the waste residue pickling waste liquid, which has good economic benefit.

[0027] In the second aspect, the application provides a preparation method of a chloride ion adsorbent, which adopts the following technical solution:

[0028] The preparation method of the chloride ion adsorbent comprises the following steps:

[0029] After the amino silane and water are stirred and mixed, the aluminum magnesium hydrotalcite is added and stirred and mixed, and then the chloride ion adsorbent is obtained after aging, water washing, drying and grinding.

[0030] The weight ratio of the aluminum magnesium hydrotalcite, the amino silane coupling agent and water is 1:(0.025-0.055):(3-6).

[0031] The amino silane can be polymerized to form a gel after hydrolysis, by controlling the weight ratio of the aluminum magnesium hydrotalcite, the amino silane coupling agent and the water, the aluminum magnesium hydrotalcite not only retains the interlayer structure, but also the surface can adsorb the gel with amino active sites, and the aluminum magnesium hydrotalcite has good adsorption of the chloride ions and the divalent iron ions in the waste residue pickling waste liquid, and has good removal rates of the chloride ions and the divalent iron ions.

[0032] Preferably, the preparation method of the chloride ion adsorbent comprises the following steps:

[0033] The amino silane coupling agent and the water are stirred and mixed first, then the aluminum magnesium hydrotalcite and the water-soluble non-ionic cellulose ether are added and stirred and mixed, aging, water washing, drying and grinding are performed to obtain the chloride ion adsorbent.

[0034] The weight ratio of the aluminum magnesium hydrotalcite, the amino silane coupling agent, the water-soluble non-ionic cellulose ether and the water is 1:(0.025-0.055):(0.01-0.015):(3-6).

[0035] By adopting the above technical scheme, the water-soluble non-ionic cellulose ether has good suspension stability, which is beneficial to obtaining the aluminum magnesium hydrotalcite with the surface uniformly adsorbed with the gel, and can effectively improve the adsorption rate of the chloride ion adsorbent to the chloride ions and the divalent iron ions.

[0036] In summary, the present application has the following beneficial effects:

[0037] 1. The pH value of the pickling waste liquid is adjusted by using limestone first, and then the waste residue pickling waste liquid is treated by using the chloride ion adsorbent, which not only can reduce the content of the chloride ions and the divalent iron ions in the waste residue pickling waste liquid, but also can reduce the use of a large amount of alkaline chemical raw materials, effectively avoids the heat release of the neutralization reaction of strong acid and strong base, and improves the environmental protection and safety of the hot galvanizing waste residue pickling waste liquid treatment method; 2. In the present application, the aluminum magnesium hydrotalcite with a layered structure is used as a carrier, and the amino silane is used as a gel raw material to prepare the chloride ion adsorbent with the interlayer structure and the amino active site, which has a high divalent iron adsorption rate and a high chloride ion adsorption rate, and has wide applicability in the water treatment field. DETAILED DESCRIPTION

[0038] The present application is further described below in combination with examples.

[0039] The raw materials used in the examples of the present application are all commercially available, except for the following special descriptions.

[0040] The aluminum magnesium hydrotalcite has a magnesium aluminum molar ratio of 2.25g / Al, an effective ingredient content of 99%, and an average particle size of ≤1.0;

[0041] Hydroxyethyl cellulose, molar substitution degree 1.8-2.0, pH value 6.0-8.5, viscosity 5-60000 mpa·s;

[0042] Sodium carboxymethyl cellulose, model 9032-42-2, purchased from Shanghai Hongzhuang Chemical Technology Co., Ltd.;

[0043] Sodium alginate, sodium alginate ≥ 50%, sodium sulfate < 40%, sodium hexametaphosphate < 10%, pH value 6.0-8.0.

[0044] Preparation example

[0045] Preparation example 1

[0046] A chloride ion adsorbent, each raw material and its corresponding weight (g) is shown in the following table.

[0047]

[0048] The preparation method of the above chloride ion adsorbent is: first, the amino silane coupling agent and water are stirred and mixed at 800 r / min for 30 min, then the aluminum magnesium hydrotalcite is added and stirred and mixed for 60 min, aged for 24 h, washed with water, dried, ground, and the chloride ion adsorbent is obtained.

[0049] Preparation examples 2-3

[0050] A chloride ion adsorbent, different from preparation example 1, each raw material and its corresponding weight (g) is shown in the following table.

[0051]

[0052]

[0053] Preparation examples 4-6

[0054] A chloride ion adsorbent, different from preparation example 1, the amino silane coupling agent and its corresponding weight (g) is shown in the following table.

[0055]

[0056] Preparation examples 7-10

[0057] A chloride ion adsorbent, different from preparation example 1, further comprising a water-soluble cellulose ether, the weight (g) of the water-soluble cellulose ether is shown in the following table.

[0058]

[0059] The preparation method of the above-mentioned chloride ion adsorbent is: first, the amino silane coupling agent and water are stirred and mixed at 800 r / min for 30 min, then the aluminum magnesium hydrotalcite and water-soluble cellulose ether are added and stirred and mixed at 60℃ for 60 min, aged for 24 h, washed with water, dried, ground, and the chloride ion adsorbent is obtained.

[0060] Preparation Example 11

[0061] A chloride ion adsorbent, which is different from that of Preparation Example 1 in that equal weight of amino silane coupling agent is used instead of aluminum magnesium hydrotalcite.

[0062] The preparation method of the above-mentioned chloride ion adsorbent is: first, the amino silane coupling agent and water are stirred and mixed at 800 r / min for 30 min, then the aluminum magnesium hydrotalcite and water-soluble cellulose ether are added and stirred and mixed at 60℃ for 60 min, aged for 24 h, washed with water, dried, ground, and the chloride ion adsorbent is obtained.

[0063] Preparation Example 12

[0064] A chloride ion adsorbent, which is aluminum magnesium hydrotalcite.

[0065] Embodiment

[0066] Embodiment 1

[0067] A hot galvanizing waste residue pickling waste liquid treatment method, comprising the following steps:

[0068] S1: adding the chloride ion adsorbent into the waste residue pickling waste liquid with pH value of 3, stirring and mixing at room temperature (20-25℃) for 90 min, and obtaining a mixed liquid;

[0069] S2: adding sodium alginate into the mixed liquid, stirring and mixing for 60 min, precipitating for 180 min, filtering, adjusting the pH value of the filtrate to 6-7 with caustic alkali, aeration, precipitating for 120 min, filtering, and obtaining the treated waste residue pickling waste liquid.

[0070] In the embodiment, the chloride ion adsorbent is the chloride ion adsorbent prepared in Preparation Example 1;

[0071] The feeding amount of the chloride ion adsorbent in the waste residue pickling waste liquid with pH value of 3 is 1.5 g / L;

[0072] The feeding amount of the sodium alginate in the waste residue pickling waste liquid with pH value of 3 is 0.15 g / L.

[0073] The caustic alkali is sodium hydroxide;

[0074] The aeration amount is 18Q, and the time is 5 h.

[0075] Embodiments 2-10

[0076] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0077] Example Preparation Example Example 1 Preparation Example 1 Example 2 Preparation Example 2 Example 3 Preparation Example 3 Example 4 Preparation Example 4 Example 5 Preparation Example 5 Example 6 Preparation Example 6 Example 7 Preparation Example 7 Example 8 Preparation Example 8 Example 9 Preparation Example 9 Example 10 Preparation Example 10

[0078] Example 11

[0079] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0080] Example 12

[0081] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0082] Comparative example

[0083] Comparative example 1

[0084] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0085] Comparative example 2

[0086] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0087] Comparative example 3

[0088] A hot galvanizing waste residue pickling waste liquid treatment method, different from example 1, in S1, the chloride ion adsorbent is prepared by the chloride ion adsorbent in the following table.

[0089] Performance detection

[0090] The waste residue pickling waste liquid treated by the hot galvanizing waste residue pickling waste liquid treatment method of example 1-12 and comparative example 1-3 is detected for chloride ion removal rate and iron concentration, and the detection method is as follows:

[0091] Chloride ion removal rate: the chloride ion concentration is detected according to GB / T 11896-1989, and the chloride ion removal rate is calculated according to the following formula:

[0092] Chloride ion removal rate = (concentration of chloride ions in the waste residue pickling waste liquid in S1 - concentration of chloride ions in the treated waste residue pickling waste liquid in S2) / concentration of chloride ions in the waste residue pickling waste liquid in S1;

[0093] Iron concentration: detected according to GB 13456-2012 "Discharge Standard of Water Pollutants for Iron and Steel Industry".

[0094] The detection results are shown in the following table.

[0095]

[0096]

[0097] According to the provisions of GB 13456-2012 "Discharge Standard of Water Pollutants for Iron and Steel Industry", the limit value of total iron in the discharge of water pollutants in the iron and steel industry is 10 mg / L.

[0098] Through data analysis of the above table, it can be seen that the iron content of the waste residue pickling waste liquid treated by the hot galvanizing waste residue pickling waste liquid treatment method of embodiments 1-12 is as low as 0.15-0.66 mg / L, which meets the provisions of GB 13456-2012 "Discharge Standard of Water Pollutants for Iron and Steel Industry".

[0099] The chloride ion removal rate of the waste residue pickling waste liquid treated by embodiments 1, 4, and 5 is as high as 88.00-90.00%, and the chloride ion removal rate of the waste residue pickling waste liquid treated by embodiment 6 is as low as 84.30%. This shows that in the hot galvanizing waste residue pickling waste liquid treatment method of the present application, the chloride ion adsorbent prepared from 3-aminopropylmethyldimethoxysilane and / or N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane can improve the chloride ion removal rate of the waste residue pickling waste liquid.

[0100] The chloride ion removal rate of the waste residue pickling waste liquid treated by embodiments 1, 8, and 9 is as high as 90.00-91.60%, and the chloride ion removal rate of the waste residue pickling waste liquid treated by embodiment 10 is as low as 83.60%. This shows that in the hot galvanizing waste residue pickling waste liquid treatment method of the present application, the chloride ion adsorbent prepared from water-soluble non-ionic cellulose ether can improve the chloride ion removal rate of the waste residue pickling waste liquid.

[0101] Compared with the pickling waste liquid treated by the method of Example 1, the removal rate of chloride ions in the pickling waste liquid treated by the method of Example 11 is obviously reduced, but the removal rate of chloride ions in the pickling waste liquid treated by the method of Example 12 is slightly increased. It is shown that in the method for treating the pickling waste liquid of hot galvanizing slag, increasing the amount of the chloride ion adsorbent can improve the removal rate of chloride ions in the pickling waste liquid. However, the difference in the removal rate of chloride ions is not obvious when the amount of the chloride ion adsorbent is 1.5 g / L and 1.8 g / L. Therefore, when the amount of the chloride ion adsorbent in the pickling waste liquid is 0.6-1.8 g / L, the chloride ion adsorbent can have good removal rate of chloride ions and economic benefits.

[0102] Compared with the pickling waste liquid treated by the method of Example 1, the removal rate of chloride ions in the pickling waste liquid treated by the method of Comparative Example 1 and Comparative Example 2 is relatively reduced by 23.78-31.00%. It is shown that in the method for treating the pickling waste liquid of hot galvanizing slag, using the aluminum-magnesium hydrotalcite as a carrier to adsorb the polymer after the hydrolysis of the amino silane coupling agent, the prepared chloride ion adsorbent can improve the removal rate of chloride ions in the pickling waste liquid.

[0103] Compared with the pickling waste liquid treated by the method of Example 1, the removal rate of chloride ions in the pickling waste liquid treated by the method of Comparative Example 3 is relatively reduced by 19.89%. It is shown that in the method for treating the pickling waste liquid of hot galvanizing slag, the chloride ion adsorbent has good adsorption activity in the pickling waste liquid with pH value of 3-4, and has good removal efficiency of chloride ions in the pickling waste liquid.

[0104] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A hot galvanizing waste slag pickling waste liquid treatment method, characterized by, The method comprises the following steps: S1: adding a chloride ion adsorbent into a waste residue pickling waste liquid with a pH value of 3-4, and stirring to obtain a mixed liquid; S2: adding sodium alginate into the mixed liquid, stirring, filtering, adjusting the pH value of the filtrate to 6-7 with caustic soda, and obtaining a treated waste residue pickling waste liquid; The preparation method of the chloride ion adsorbent comprises the following steps: stirring and mixing an amino silane coupling agent and water, adding aluminum magnesium hydrotalcite, stirring and mixing, aging, washing with water, drying, and grinding to obtain the chloride ion adsorbent; In the preparation method of the chloride ion adsorbent, the weight ratio of aluminum magnesium hydrotalcite, the amino silane coupling agent and water is 1:(0.025-0.055):(3-6); The amino silane is one or both of 3-aminopropylmethyldimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane.

2. The hot galvanizing slag pickling waste liquid treatment method according to claim 1, characterized by, The amino silane is composed of 3-aminopropylmethyldimethoxysilane and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane at a weight ratio of 1:(0.45-0.65).

3. The hot galvanizing slag pickling waste liquid treatment method according to claim 1, characterized by, The preparation method of the chloride ion adsorbent comprises the following steps: stirring and mixing an amino silane coupling agent and water, adding aluminum magnesium hydrotalcite and a non-ionic water-soluble cellulose ether, stirring and mixing, aging, washing with water, drying, and grinding to obtain the chloride ion adsorbent; The weight ratio of aluminum magnesium hydrotalcite, the amino silane coupling agent, the non-ionic water-soluble cellulose ether and water is 1:(0.025-0.055):(0.01-0.015):(3-6).

4. The hot galvanizing slag pickling waste liquid treatment method according to claim 3, characterized by, The non-ionic water-soluble cellulose ether is methylhydroxyethyl cellulose or hydroxyethyl cellulose.

5. The hot galvanizing slag pickling waste liquid treatment method according to claim 4, characterized by, The hydroxyethyl cellulose has a molar substitution degree of 1.8-2.0, a pH value of 6.0-8.5, and a viscosity of 5-60000 mpa·s.

6. The hot galvanizing slag pickling waste liquid treatment method according to claim 1, characterized by, The feeding amount of the chloride ion adsorbent in the waste residue pickling waste liquid with a pH value of 3-4 is 0.6-1.8 g / L.

Images