Collecting agent for residual chlorine on surface of pickled steel plate, preparation method of collecting agent and residual chlorine determination method

Abstract

The invention relates to a collecting agent for residual chlorine on the surface of a pickled steel plate, a preparation method of the collecting agent and a residual chlorine determination method. The residual chlorine collecting agent comprises the following components in percentage by mass: 1-3% of fatty alcohol-polyoxyethylene ether, 10-25% of acetic acid, 1-2.5% of sodium acetate and the balance of deionized water. The surface of the steel plate is heated at high temperature in advance, so that the surface of the steel plate is converted into an oxide layer, and the reaction speed can be greatly increased; the formula of the residual chlorine collecting agent is scientific, residual chlorine ions on the surface of the steel plate can be effectively collected, and the accuracy and high efficiency of residual chlorine collection are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corrosion detection, and particularly relates to a residual chlorine collection agent for a steel plate surface after pickling, a preparation method thereof and a residual chlorine determination method. BACKGROUND

[0002] In the field of steel processing, especially in the process of cold rolling, pickling is a crucial surface treatment process, mainly used to remove the oxide scale and rust on the surface of the steel plate, providing a clean and activated surface for subsequent processing. Currently, hydrochloric acid and other acidic solutions are commonly used for pickling in industry.

[0003] However, a significant challenge in the pickling process is that the surface of the treated steel plate inevitably contains trace amounts of specific ionic components (hereinafter referred to as "corrosive residual ions"). Although the content of these residues is very low, due to their physical and chemical properties (such as small size, strong diffusion ability, high reactivity, etc.), they pose a serious threat to the subsequent corrosion resistance of the steel plate. Specifically, these corrosive residual ions can easily adsorb and accumulate on the surface of the steel plate, damaging the integrity of the passivation protective film obtained through natural formation or subsequent treatment. This damaging effect can easily induce localized corrosion of the steel plate, significantly increasing the risk of corrosion failure such as pitting corrosion during storage, transportation, and subsequent use. This corrosion not only damages the appearance of the product, but also seriously affects the mechanical properties and service life of the steel.

[0004] It is widely recognized in the industry that the content of corrosive residual ions on the surface of the steel plate is one of the key control parameters affecting its long-term corrosion resistance. In order to effectively suppress the above corrosion risks and ensure product quality and prolong service life, it is crucial to accurately, efficiently, and timely monitor and control the content of key corrosive residual ions on the surface of the steel plate after pickling. However, existing monitoring methods mostly have problems such as poor real-time performance, insufficient accuracy, high cost, or difficulty in online integration, making it difficult to fully meet the needs of modern continuous production for rapid response and precise control. SUMMARY

[0005] The present application provides a residual chlorine collection agent for a steel plate surface after pickling, a preparation method thereof and a residual chlorine determination method. The method uses pre-heating the steel plate surface at high temperature to convert the steel plate surface into an oxide layer, which greatly accelerates the reaction speed. The formula of the residual chlorine collection agent is scientific, which can effectively collect the residual chlorine ions on the surface of the steel plate and ensure the accuracy and efficiency of the residual chlorine collection.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] An acid pickling steel plate surface residual chlorine collection agent, the residual chlorine collection agent is composed of the following components in percentage by mass: 1-3% of fatty alcohol polyoxyethylene ether, 10-25% of acetic acid, 1-2.5% of sodium acetate, and the balance of deionized water.

[0008] A preparation method of an acid pickling steel plate surface residual chlorine collection agent, comprising the following steps:

[0009] 1) weighing reagent: weighing reagent according to the ratio, first weighing fatty alcohol polyoxyethylene ether and placing it in a beaker; then weighing acetic acid and adding it into the beaker, and then weighing sodium acetate and adding it into the beaker;

[0010] 2) add deionized water: slowly pour deionized water into the beaker according to the ratio, and stir while pouring;

[0011] 3) stirring: fully stir the solution until the solution is uniform, that is, the residual chlorine collection agent is obtained.

[0012] In step 1), an analytical balance is used for weighing.

[0013] In step 3), the solution is stirred using a stirring rod or a magnetic stirrer, and the stirring time is 10-20 min.

[0014] A method for determining residual chlorine on the surface of acid-pickled steel plate, comprising the following steps:

[0015] 1) selecting a sample area with uniform surface and no pollution on the acid-pickled steel plate, wrapping the sample area with plastic film, and cutting a sample with length x width = 250-300 mm x 50-100 mm, the width direction of the sample is consistent with the rolling direction of the steel plate;

[0016] 2) place the sample on a ceramic crucible and put it in a muffle furnace, heat at a temperature of 550-650 DEG C for 10-20 min, then take out the sample;

[0017] 3) place the sample in an impermeable tray and add the residual chlorine collection agent; place the sample-loaded impermeable tray on an electric heating plate and heat to 55-65 DEG C, wipe the sample surface with degreasing cotton while heating, for 5-10 min;

[0018] 4) take out the sample, rinse the degreasing cotton and the sample surface, filter the rinse liquid and the extraction liquid, transfer to a flask and place in a shaking incubator, shake at a temperature of 50-60 DEG C for 20-30 min;

[0019] 5) move the flask to an electric oven and dry the solution in the flask to 20-25 mL at a temperature of 90-95 DEG C; after the solution cools down, transfer the solution to a 100 mL volumetric flask and dilute to volume;

[0020] 6) Determining the content of chloride ions by ion chromatography.

[0021] In step 6), the content of chloride ions is calculated according to formula (1):

[0022]

[0023] In the formula: N - the content of residual chloride ions on both sides of the sample plate, in mg / m 2 ;

[0024] P - the concentration of chloride ions in the sample, in mg / L;

[0025] V - the volume of the constant volume, in L;

[0026] a - the length of the measured area, in m;

[0027] b - the width of the measured area, in m.

[0028] Compared with the prior art, the beneficial effects of the present application are:

[0029] 1) Efficient collection of residual chlorine;

[0030] The present application adopts the method of pre-heating the surface of the steel plate to convert the surface of the steel plate into an oxide layer, which can greatly accelerate the reaction speed; the formula of the residual chlorine collector used is scientific, and through the combination of specific proportions of fatty alcohol polyoxyethylene ether, acetic acid, sodium acetate and deionized water, the residual chlorine on the surface of the steel plate can fully react with the residual chlorine on the surface of the steel plate during the heating and wiping process, thereby efficiently collecting the residual chlorine ions on the surface of the steel plate; the collection steps from selecting the sample plate area, heating treatment to using the collector to wipe the heating, each link cooperates with each other, which maximizes the accuracy and efficiency of the collection of residual chlorine.

[0031] 2) Simple and reliable operation;

[0032] The preparation method of the residual chlorine collector is simple, and the required materials and equipment are common and easy to obtain. The collection method of the residual chlorine on the surface of the steel plate is easy to operate, and the steps such as selecting the sample plate area, heating treatment, adding the collector and wiping are clear, without the need for complex technology and professional operators, which is suitable for large-scale industrial production application.

[0033] 3) Controllable parameters;

[0034] The ratio of the residual chlorine collector is clear, and by using an analytical balance to accurately weigh each component and using a pH meter to detect each parameter of the solution, the performance of the residual chlorine collector can be ensured to be stable and reliable. The heating temperature and time parameters in the collection process are optimized, which can ensure the collection effect. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is the sampling position and sampling size when the surface residual chlorine of the steel plate described in the present application is determined. DETAILED DESCRIPTION

[0036] The acid-washed steel plate surface residual chlorine collection agent described in the present application is composed of the following components in percentage by mass: 1-3% of fatty alcohol polyoxyethylene ether, 10-25% of acetic acid, 1-2.5% of sodium acetate, and the balance of deionized water.

[0037] A preparation method of an acid-washed steel plate surface residual chlorine collection agent, comprising the following steps:

[0038] 1) weighing reagents: weigh the reagents according to the ratio, first weigh the fatty alcohol polyoxyethylene ether and place it in a beaker; then weigh the acetic acid and add it to the beaker, and then weigh the sodium acetate and add it to the beaker;

[0039] 2) add deionized water: slowly pour the deionized water into the beaker according to the ratio, stirring while pouring;

[0040] 3) stir evenly: stir the solution thoroughly until the solution is uniform, i.e. the residual chlorine collection agent is obtained.

[0041] In step 1), an analytical balance is used for weighing.

[0042] In step 3), a stirring rod or a magnetic stirrer is used to stir the solution, and the stirring time is 10-20 min.

[0043] The acid-washed steel plate surface residual chlorine determination method described in the present application comprises the following steps:

[0044] 1) select a uniform surface and no pollution sample area on the acid-washed steel plate, wrap the sample area with plastic film, and cut a sample with length x width = 250-300 mm x 50-100 mm, the width direction of the sample is consistent with the rolling direction of the steel plate (as shown in Figure 1

[0045] 2) place the sample on a ceramic crucible and place it in a muffle furnace, heat at 550-650℃ for 10-20 min, then take out the sample;

[0046] 3) place the sample in an impermeable tray and add the residual chlorine collection agent; place the sample-loaded impermeable tray on an electric heating plate and heat to 55-65℃, wipe the sample surface with degreasing cotton while heating, for 5-10 min;

[0047] ​4) Take out the sample, rinse the defatted cotton and the surface of the sample, filter the rinsing liquid and the extraction liquid, transfer to a flask and place in a shaking incubator, shake extraction at a temperature of 50-60℃ for 20-30 min;

[0048] 5) Move the flask to an electric heating oven, dry the solution in the flask to 20-25 mL at a temperature of 90-95℃; after the solution cools, transfer the solution to a 100 mL volumetric flask and make up to volume;

[0049] 6) Determine the content of chloride ions by ion chromatography.

[0050] In step 6), the content of chloride ions is calculated according to formula (1):

[0051]

[0052] In the formula, N is the content of residual chloride ions on both sides of the sample plate, in mg / m 2 ;

[0053] ρ is the concentration of chloride ions in the sample, in mg / L;

[0054] V is the volume of the constant volume, in L;

[0055] a is the length of the measured area, in m;

[0056] b is the width of the measured area, in m.

[0057] In order to more intuitively embody the present application, the embodiments of the present application are further described in combination with examples. The following examples are only preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can obviously obtain technical solutions within the technical range disclosed by the present application, including simple changes or equivalent replacements, which are within the protection scope of the present application.

[0058]

Example 1

[0059] In this embodiment, the preparation process of the residual chlorine collection agent on the surface of the steel plate after pickling is as follows:

[0060] 1. Prepare materials and equipment:

[0061] Prepare fatty alcohol polyoxyethylene ether, acetic acid, sodium acetate and deionized water and other chemical reagents.

[0062] Prepare clean and dry beakers, volumetric flasks, stirring rods, analytical balances and other equipment.

[0063] 2. Weigh the reagents:

[0064] The fat alcohol polyoxyethylene ether accounting for 2% of the total mass of the residual chlorine collection agent was weighed using an analytical balance and placed in a beaker. Then, the acetic acid accounting for 18% of the total mass of the residual chlorine collection agent was weighed and added to the beaker. Then, the sodium acetate accounting for 2% of the total mass of the residual chlorine collection agent was weighed and also placed in the beaker.

[0065] 3. Deionized water was added:

[0066] The remaining mass of the residual chlorine collection agent was supplemented with deionized water. The deionized water was slowly poured into the beaker while stirring to prevent the solution from splashing. In this embodiment, a stirring rod was used to thoroughly stir the solution. The solution was stirred for 15 minutes until it appeared uniform.

[0067] The residual chlorine collection agent was observed. The solution appeared clear and transparent with no obvious impurities and precipitates. The solution parameters were detected using a pH meter, which met the expected requirements.

[0068] In this embodiment, the process of measuring the residual chlorine on the surface of the steel plate was as follows:

[0069] 1. A sample area with a uniform surface and no contamination was selected on the pickled steel plate. The sample area was completely wrapped with plastic film to prevent contamination of the sample area during sampling. Then, a sample with a length x width of 280 mm x 80 mm was cut from the sample area. The width direction of the sample was consistent with the rolling direction of the steel plate.

[0070] 2. The sample was placed on a clean square ceramic crucible and placed in a muffle furnace. After heating at 600°C for 15 minutes, the sample was removed.

[0071] 3. The sample was placed in a PP impermeable tray, and the residual chlorine collection agent was added. The PP impermeable tray with the cut sample was placed on an electric heating plate and heated to 60°C. The sample surface was wiped with absorbent cotton while heating for 8 minutes.

[0072] 4. The sample was removed, and the absorbent cotton and sample surface were rinsed. The rinse liquid and extract were filtered and transferred to a flask and placed in a shaking incubator. The solution was shaken at 55°C for 25 minutes.

[0073] 5. The flask was moved to an electric heating oven, and the solution in the flask was dried to 23 mL at 92°C. After the solution cooled, the solution was transferred to a 100 mL volumetric flask and diluted to volume.

[0074] 6. The content of chloride ions was determined by ion chromatography. The results are shown in Table 1:

[0075] Table 1 Residual Chloride Ion Content

[0076] Sample No. Analysis Item Unit Test Result 1 Surface Chloride Residue (Double Side) mg / m 2 ]] 6.12

[0077]

Example 2

[0078] In this embodiment, the preparation process of the residual chlorine collection agent on the surface of the steel plate after pickling is as follows:

[0079] 1. Prepare materials and equipment:

[0080] Prepare chemical reagents such as fatty alcohol polyoxyethylene ether, acetic acid, sodium acetate, and deionized water.

[0081] Prepare clean and dry equipment such as beakers, volumetric flasks, magnetic stirrers, analytical balances, etc.

[0082] 2. Weigh the reagents:

[0083] Use the analytical balance to weigh 1% of the total mass of the residual chlorine collection agent into a beaker, then weigh 25% of the total mass of the residual chlorine collection agent into the beaker, and then weigh 1% of the total mass of the residual chlorine collection agent into the beaker.

[0084] 3. Add deionized water:

[0085] The remaining mass of the residual chlorine collection agent is supplemented with deionized water. Slowly pour the deionized water into the beaker while stirring to prevent the solution from splashing. In this embodiment, the magnetic stirrer is used to fully stir the solution. Stir for 20 minutes until the solution is uniform, i.e. the residual chlorine collection agent is prepared.

[0086] Observe the residual chlorine collection agent. The solution is clear and transparent with no obvious impurities or precipitates. Use a pH meter to detect the solution parameters, which meet the expected requirements.

[0087] In this embodiment, the process of measuring residual chlorine on the surface of the steel plate is as follows:

[0088] 1. Select a sample area on the steel plate after pickling that is uniform in surface and free of contamination. Wrap the sample area completely with plastic film to avoid contamination of the sample area during sampling, then cut a sample with dimensions of 300mm x 100mm from the sample area, with the width direction of the sample consistent with the rolling direction of the steel plate.

[0089] 2. Place the sample on a clean square ceramic crucible and place it in a muffle furnace. Heat at 650°C for 10 minutes, then remove the sample.

[0090] 3. Place the sample in a PP impermeable tray and add the residual chlorine collection agent. Place the PP impermeable tray with the sample cut in it on an electric heating plate and heat to 65°C. Wipe the surface of the sample with absorbent cotton while heating for 5 minutes.

[0091] 4. Remove the sample and rinse the absorbent cotton and the surface of the sample. Filter the rinse liquid and the extraction liquid, transfer them to a flask, and place them in a shaking incubator at 60°C for 20 minutes.

[0092] 5. The flask is moved to the electric oven and the solution in the flask is dried to 25 mL at 90°C; after the solution is cooled, the solution is transferred to a 100 mL volumetric flask and diluted to volume;

[0093] 6. The ion chromatography method is used to determine the content of chloride ions, and the determination results are shown in Table 2:

[0094] Table 2: Residual chloride ion content

[0095] Sample No. Analysis Item Unit Test Result 2 Surface Chloride Residue (Double Side) mg / m 2 ]] 15.45

[0096] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art, according to the technical solution and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An acid-washing post-steel sheet surface residual chlorine collection agent, characterized by, The residual chlorine collection agent is composed of the following components in percentage by mass: 1-3% of fatty alcohol polyoxyethylene ether, 10-25% of acetic acid, 1-2.5% of sodium acetate, and the balance of deionized water.

2. A method for producing the pickling after steel sheet surface residual chlorine collecting agent according to claim 1, characterized by, The method comprises the following steps: 1) weighing reagents: weighing reagents according to the ratio, first weighing fatty alcohol polyoxyethylene ether and placing it in a beaker; then weighing acetic acid and adding it into the beaker, and then weighing sodium acetate and adding it into the beaker; 2) adding deionized water: slowly pouring deionized water into the beaker according to the ratio, stirring while pouring; 3) stirring uniformly: fully stirring the solution until the solution is uniform, i.e. obtaining the residual chlorine collection agent.

3. The method according to claim 2, wherein the pickling residue collector is prepared by mixing 0.1 to 0.5 parts by weight of the polyvinyl alcohol with 99.5 to 99.9 parts by weight of water. In the step 1), an analytical balance is used for weighing.

4. The method according to claim 2, wherein the pickling residue collector is prepared by adding 0.1 to 0.5 parts by weight of the surfactant to 100 parts by weight of the inorganic powder. In the step 3), a stirring rod or a magnetic stirrer is used to stir the solution, and the stirring time is 10-20 min.

5. A method for measuring residual chlorine on the surface of a pickled steel sheet, characterized by using the residual chlorine collector for a pickled steel sheet according to claim 1. The method comprises the following steps: 1) selecting a sample area with uniform surface and no pollution on the pickled steel plate, wrapping the sample area with plastic film, and cutting a sample with a length x width of 250-300 mm x 50-100 mm, the width direction of the sample being consistent with the rolling direction of the steel plate; 2) placing the sample on a ceramic crucible and placing it in a muffle furnace, heating at a temperature of 550-650 ℃ for 10-20 min, and then taking out the sample; 3) placing the sample in an impermeable tray and adding the residual chlorine collection agent; placing the sample-loaded impermeable tray on an electric heating plate and heating to 55-65 ℃, wiping the surface of the sample with degreasing cotton while heating, for 5-10 min; 4) taking out the sample, rinsing the degreasing cotton and the surface of the sample, filtering the rinsing liquid and the extraction liquid, transferring them to a flask and placing them in a shaking incubator, and oscillating extraction at a temperature of 50-60 ℃ for 20-30 min; 5) moving the flask to an electric heating oven, drying the solution in the flask to 20-25 mL at a temperature of 90-95 ℃; after the solution cools down, transferring the solution to a 100 mL volumetric flask and making up to volume; 6) determining the chloride ion content by ion chromatography.

6. The method according to claim 5, wherein the acid pickling solution is an aqueous solution of hydrochloric acid. In the step 6), the chloride ion content is calculated according to formula (1): where: N = sample panel both-side residual chloride ion content, in mg / m 2 ; ρ——chloride ion concentration in the sample, unit: mg / L; V——volume of the constant volume, unit: L; a——length of the measured area, unit: m; b——width of the measured area, unit: m.

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