Steel pipe cleaning mixed solution, preparation method thereof and method for cleaning pollutants on surface of steel pipe

Abstract

The invention discloses a steel pipe cleaning mixed solution, a preparation method thereof and a method for cleaning pollutants on the surface of a steel pipe, and belongs to the field of metal surface treatment. The invention aims to solve the problems of low cleaning efficiency, non-uniform surface treatment effect, poor system stability and the like due to the adoption of a single acidic medium or a simple compound system in the traditional steel pipe cleaning method. According to the method, a mixed solution composed of nitric acid, ammonium bifluoride, sodium sulfate, 1-hydroxyethylidene-1, 1-diphosphonic acid, pyridinium propane sulfonate, a brightener, an emulsifier and water is adopted as a steel pipe cleaning medium. The steel pipe cleaning agent is scientific in formula component matching, high in cleaning efficiency, capable of effectively improving the surface state of a steel pipe, simple, convenient and feasible in operation process, environmentally friendly, suitable for batch cleaning treatment of related steel pipes and good in practicability and economical efficiency.

Description

A steel pipe cleaning solution, its preparation method, and a method for cleaning contaminants from the surface of steel pipes. Technical Field

[0001] This invention belongs to the field of metal surface treatment, specifically relating to a steel pipe cleaning solution and its preparation method, as well as a method for cleaning contaminants from the surface of steel pipes using the steel pipe cleaning solution. This invention is applicable to batch cleaning of steel pipes, and is particularly suitable for steel pipe pretreatment processes that require removal of surface oxide scale and stains and improvement of surface finish. Background Technology

[0002] During production, storage, and use, steel pipes are prone to developing contaminants such as oxide scale, rust products, and oil stains on their surface. These contaminants can affect the quality of subsequent processing (such as painting and welding), reduce product lifespan, and even impact safety. Traditional steel pipe cleaning methods often employ single acidic media or simple compound systems, resulting in low cleaning efficiency, uneven surface treatment, and poor system stability. Some cleaning solutions also suffer from strong corrosiveness and poor environmental performance, making it difficult to meet the demands of modern mass production for efficient, environmentally friendly, and high-quality cleaning processes. Summary of the Invention

[0003] This invention proposes a steel pipe cleaning medium with a scientific formula, excellent cleaning effect, environmental friendliness and simple operation, which can achieve efficient removal of contaminants on the surface of steel pipes and optimization of surface condition, while reducing the environmental impact of the cleaning process and improving production efficiency and economy.

[0004] To address the aforementioned technical problems, this invention employs the following technical solution: This invention uses a mixed solution with a specific formulation, composed of varying amounts of nitric acid, ammonium hydrogen fluoride, sodium sulfate, hydroxyethylidene diphosphate, pyridinium propane sulfonate, brightener, emulsifier, and water, as the steel pipe cleaning medium. The components in the formulation work synergistically: nitric acid provides an acidic cleaning environment, effectively removing oxide scale and stains from the steel pipe surface; ammonium hydrogen fluoride utilizes fluoride ions to form complexes with elements such as chromium and nickel in stainless steel and iron, disrupting the passivation film on the metal surface and achieving a dissolution effect; sodium sulfate and hydroxyethylidene diphosphate optimize the system's stability and cleaning effect; pyridinium propane sulfonate and brightener ensure the surface smoothness of the steel pipe after cleaning; the emulsifier enhances the compatibility of the components; and water acts as a solvent to adjust the system concentration. The advantages of this cleaning method lie in its scientifically formulated components, high cleaning efficiency, effective improvement of the steel pipe surface condition, simple and easy operation, environmental friendliness, and suitability for batch cleaning of relevant steel pipes, demonstrating good practicality and economy.

[0005] The purpose of this invention is to provide a steel pipe cleaning mixture, which is composed of nitric acid, ammonium hydrogen fluoride, sodium sulfate, hydroxyethylidene diphosphate, pyridinium propane sulfonate, brightener, emulsifier, and water. Further, by weight, the proportions of each component are as follows: 306 parts nitric acid, 5-15 parts ammonium hydrogen fluoride, 6 parts sodium sulfate, 3 parts hydroxyethylidene diphosphate, 1.5 parts pyridinium propane sulfonate, 5 parts brightener, 3 parts emulsifier, and 660.5-670.5 parts water, with a total of 1000 parts.

[0006] To further specify, the brightener is brightener LD.

[0007] Further specifying, the emulsifier is emulsifier OP-10.

[0008] Another objective of this invention is to provide a method for preparing any of the above-described steel pipe cleaning mixed solutions, comprising the following steps: Step 1: Pour the weighed water into a stirring container, and slowly add nitric acid along the container wall into the water (do not pour water into nitric acid to avoid the strong acid dilution releasing heat and splashing), stirring gently while adding until the mixture is uniform; Step 2: Add ammonium hydrogen fluoride and sodium sulfate in sequence, stirring for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles remaining; Step 3: Continue to add hydroxyethylidene diphosphate, pyridinium propanesulfonate, brightener, and emulsifier, stirring for 1-2 minutes after each addition to ensure that the additives are fully integrated with the solution; Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a uniform and transparent cleaning mixed solution.

[0009] Another objective of this invention is to provide a method for cleaning contaminants on the surface of steel pipes, comprising the following steps: Step 1, placing the steel pipe cleaning mixture solution according to any one of claims 1-7 into a cleaning tank, and then immersing the steel pipe to be cleaned in the steel pipe cleaning mixture solution for a period of time; Step 2, after cleaning, removing the steel pipe, rinsing it with clean water, and air-drying it.

[0010] Furthermore, the soaking time is specified as 15-60 minutes.

[0011] Nitric acid provides a stable acidic environment for the cleaning system, rapidly dissolving oxide scale, rust, and oil stains on the steel pipe surface, laying the foundation for efficient cleaning. Ammonium hydrogen fluoride, through the formation of stable complexes between fluoride ions and metallic elements such as chromium and nickel in the steel pipe matrix, disrupts the surface passivation film, promoting the thorough removal of oxide scale and stubborn stains, thereby enhancing the cleaning effect. Sodium sulfate and hydroxyethylidene diphosphate work synergistically; the former optimizes the ionic strength of the system, while the latter exerts chelation and corrosion inhibition functions. Together, they improve the stability of the cleaning solution, preventing localized corrosion and uneven cleaning, ensuring... The cleaning process is continuous and consistent; pyridinium propane sulfonate and brightener work together, with the former improving the electrochemical state of the metal surface and the latter filling microscopic defects on the surface, synergistically ensuring the smoothness and flatness of the steel pipe after cleaning; emulsifiers enhance the compatibility and dispersibility of each component in the aqueous phase, avoid stratification and precipitation, maintain the uniformity and stability of the cleaning solution, and ensure that each steel pipe can obtain a uniform cleaning effect; water acts as a solvent to adjust the system concentration, providing a reaction medium for each functional component, promoting the full play of the synergistic effect of each component, and achieving efficient, stable and consistent cleaning performance.

[0012] Compared with the prior art, the present invention has the following advantages: the present invention has the characteristics of high cleaning efficiency, excellent surface treatment effect and environmental friendliness, and is suitable for batch cleaning of steel pipes.

[0013] This invention involves stirring the mixed solution evenly and then immersing the steel pipe in it. The operation is simple and easy to implement, enabling efficient batch cleaning of relevant steel pipes, and is both practical and economical.

[0014] The cleaning solution of this invention exhibits synergistic effects among its components, rapidly removing oxide scale and stains from steel pipe surfaces. Compared to traditional cleaning solutions, cleaning time is significantly reduced, meeting the needs of batch cleaning. Through the combination of propane sulfonate pyridinium salt and a brightener, the surface smoothness of the steel pipes is significantly improved after cleaning, leaving no residual stains or localized corrosion marks, providing a good surface foundation for subsequent applications. The formulation components meet environmental protection requirements, generating no large amounts of harmful gases during the cleaning process. Waste liquid treatment is simple, with minimal environmental impact. Furthermore, the solution is easy to operate, economical, and requires no complex equipment; batch processing can be achieved through immersion. The operation process is simple, with low labor and equipment investment, demonstrating excellent practicality and economy.

[0015] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0016] Figure 1 shows a comparison of the surface conditions of the steel pipes in Examples 1-3 before treatment; Figure 2 shows a comparison of the surface conditions of the steel pipes in Examples 1 and 4 before treatment; Figure 3 shows a comparison of the surface conditions of the steel pipes in Examples 1-3 after treatment with the cleaning solution; Figure 4 shows a comparison of the surface conditions of the steel pipes in Examples 1 and 4 after treatment with the cleaning solution; Figure 5 shows a comparison of the total nitrogen in the waste liquid after steel pipe treatment; Figure 6 shows a comparison of the total phosphorus in the waste liquid after steel pipe treatment. Detailed Implementation

[0017] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0018] Example 1: The steel pipe cleaning solution in this example is composed of 306g nitric acid, 5g ammonium hydrogen fluoride, 6g sodium sulfate, 3g hydroxyethylidene diphosphate, 1.5g pyridine propane sulfonate, 5g brightener (KM0203 stainless steel weld spot bright pickling solution from Dongguan Kaimeng Surface Treatment Co., Ltd.), 3g emulsifier (OP-10 emulsifier from Tianjin Zhonglian), and 670.5g water.

[0019] Step 1: Pour 670.5g of weighed water into a mixing container. Slowly add 306g of nitric acid along the container wall into the water (do not pour water into nitric acid to avoid the strong acid dilution causing heat and splashing). Stir gently while adding the nitric acid until well mixed. Step 2: Add 5g of ammonium hydrogen fluoride and 6g of sodium sulfate in sequence. Stir for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles remaining. Step 3: Continue to add 3g of hydroxyethylidene diphosphate, 1.5g of pyridinium propanesulfonate, 5g of brightener, and 3g of emulsifier. Stir for 1-2 minutes after each addition to ensure that the additives are fully mixed with the solution. Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a homogeneous and transparent cleaning mixture.

[0020] Select one ordinary steel pipe with a rough surface and contaminants, immerse it in the above cleaning solution for 30 minutes, and stir it slightly every 10 minutes during the process.

[0021] Post-processing: Remove the steel pipe, rinse it with clean water, and observe its surface condition after drying.

[0022] Results: The oxide scale and oil stains on the steel pipe surface were completely removed, the surface was smooth with slight scratches and no residual stains, but there were a few traces of rust. After cleaning, the total nitrogen content of the solution was 0.54 mg / L and the total phosphorus content was 0.003 mg / L.

[0023] Example 2: The steel pipe cleaning solution in this example is composed of 306g nitric acid, 10g ammonium hydrogen fluoride, 6g sodium sulfate, 3g hydroxyethylidene diphosphate, 1.5g pyridinium propane sulfonate, 5g brightener (KM0203 stainless steel weld spot bright pickling solution from Dongguan Kaimeng Surface Treatment Co., Ltd.), 3g emulsifier (OP-10 emulsifier from Tianjin Zhonglian), and 665.5g water.

[0024] Step 1: Pour 665.5g of weighed water into a mixing container. Slowly add 306g of nitric acid along the container wall into the water (do not pour water into nitric acid to avoid the strong acid dilution causing heat and splashing). Stir gently while adding the nitric acid until well mixed. Step 2: Add 10g of ammonium hydrogen fluoride and 6g of sodium sulfate in sequence. Stir for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles remaining. Step 3: Continue to add 3g of hydroxyethylidene diphosphate, 1.5g of pyridinium propanesulfonate, 5g of brightener, and 3g of emulsifier. Stir for 1-2 minutes after each addition to ensure that the additives are fully mixed with the solution. Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a homogeneous and transparent cleaning mixture.

[0025] Select one ordinary steel pipe with a rough surface and contaminants, immerse it in the above cleaning solution for 30 minutes, and stir it slightly every 10 minutes during the process.

[0026] Post-processing: Remove the steel pipe, rinse it with clean water, and observe its surface condition after drying.

[0027] Results: The oxide scale and oil stains on the steel pipe surface were completely removed, and the surface was dark gray. There were few stains remaining, but the smoothness was insufficient. After cleaning, the total nitrogen content of the solution was 0.55 mg / L and the total phosphorus content was 0.005 mg / L.

[0028] Example 3: The steel pipe cleaning solution in this example consists of 306g nitric acid, 15g ammonium hydrogen fluoride, 6g sodium sulfate, 3g hydroxyethylidene diphosphate, 1.5g pyridine propane sulfonate, 5g brightener (KM0203 stainless steel weld spot bright pickling solution from Dongguan Kaimeng Surface Treatment Co., Ltd.), 3g emulsifier (OP-10 emulsifier from Tianjin Zhonglian), and 660.5g water.

[0029] Step 1: Pour 660.5g of weighed water into a mixing container. Slowly add 306g of nitric acid along the container wall into the water (do not pour water into nitric acid to avoid the strong acid dilution causing heat and splashing). Stir gently while adding the nitric acid until well mixed. Step 2: Add 15g of ammonium hydrogen fluoride and 6g of sodium sulfate in sequence. Stir for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles remaining. Step 3: Continue to add 3g of hydroxyethylidene diphosphate, 1.5g of pyridinium propanesulfonate, 5g of brightener, and 3g of emulsifier. Stir for 1-2 minutes after each addition to ensure that the additives are fully mixed with the solution. Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a homogeneous and transparent cleaning mixture.

[0030] Select one ordinary steel pipe with a rough surface and contaminants, immerse it in the above cleaning solution for 30 minutes, and stir it slightly every 10 minutes during the process.

[0031] Post-processing: Remove the steel pipe, rinse it with clean water, and observe its surface condition after drying.

[0032] Results: The oxide scale and oil stains on the steel pipe surface were completely removed, and the surface was yellowish-brown with no scratches. There was a lot of rust residue. After cleaning, the total nitrogen content of the solution was 0.62 mg / L and the total phosphorus content was 0.007 mg / L.

[0033] Example 4: The steel pipe cleaning solution in this example (after dilution of Example 1 by 1 time) is composed of 153 g nitric acid, 2.5 g ammonium hydrogen fluoride, 3 g sodium sulfate, 1.5 g hydroxyethylidene diphosphate, 0.75 g pyridinium propane sulfonate, 2.5 g brightener (KM0203 stainless steel weld spot bright pickling solution from Dongguan Kaimeng Surface Treatment Co., Ltd.), 1.5 g emulsifier (OP-10 emulsifier from Tianjin Zhonglian), and 835.25 g water.

[0034] Step 1: Pour 835.25g of weighed water into a mixing container. Slowly add 153g of nitric acid along the container wall into the water (do not pour water into nitric acid to avoid the strong acid dilution releasing heat and splashing). Stir gently while adding the nitric acid until well mixed. Step 2: Add 2.5g of ammonium hydrogen fluoride and 3g of sodium sulfate in sequence. Stir for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles left. Step 3: Continue to add 1.5g of hydroxyethylidene diphosphate, 0.75g of pyridinium propanesulfonate, 2.5g of brightener, and 1.5g of emulsifier. Stir for 1-2 minutes after each addition to ensure that the additives are fully mixed with the solution. Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a homogeneous and transparent cleaning mixture.

[0035] Select the steel pipe treated in Example 3 and immerse it in the above cleaning solution for 30 minutes, stirring it slightly every 10 minutes during the process.

[0036] Post-processing: Remove the steel pipe, rinse it with clean water, and observe its surface condition after drying.

[0037] Results: The oxide scale and oil stains on the steel pipe surface were completely removed, the surface was smooth and free of scratches and residual stains, and the surface was smoother and brighter than the steel pipe surface treated in Example 1. After cleaning, the total nitrogen content of the solution was 0.55 mg / L and the total phosphorus content was 0.003 mg / L.

[0038] Effect Analysis: Comparative Examples 1-3 show that as the amount of ammonium hydrogen fluoride increases, the cleaning solution's ability to remove stubborn oxide scale and rust is enhanced, making it suitable for cleaning steel pipes with different levels of contamination. Example 1 uses the least amount of ammonium hydrogen fluoride, making it suitable for lightly contaminated steel pipes. Example 3 uses the most amount of ammonium hydrogen fluoride, making it suitable for heavily contaminated steel pipes. Example 2 is a general-purpose formula that balances cleaning effectiveness and economy.

[0039] As can be seen from Examples 1, 3 and 4, cleaning heavily contaminated steel pipes with Example 3 followed by cleaning with Example 4 increases the smoothness and brightness of the steel pipe surface.

[0040] Figures 1 and 3: The left steel pipe cleaned in Example 1 has a smooth inner wall and a small amount of residual rust on the outer wall. The inner wall has been in more thorough contact with the cleaning solution, and the oxide scale and stains have been completely removed, revealing the original smooth texture of the metal. However, the outer wall may have some residual rust marks due to incomplete soaking. It is suitable for cleaning lightly contaminated steel pipes. The middle steel pipe cleaned in Example 2 has an overall dark gray surface with no obvious luster. There are fewer stains, but the smoothness is insufficient. Most of the oxide scale has been removed, but due to the moderate amount of ammonium hydrogen fluoride, there is a slight residual "passivation layer" on the surface, so the gloss is slightly poor. The right steel pipe cleaned in Example 3 has an overall yellowish-brown surface with more residual rust, which is due to the high concentration of ammonium hydrogen fluoride. It is suitable for heavily contaminated steel pipes.

[0041] 2. Figures 2 and 4: Based on the cleaning in Example 3, the steel pipe was cleaned again in Example 4. The inner and outer walls of the steel pipe showed a smooth silver-gray metallic texture. The oxide scale and stains were completely removed, and the smooth metal cut surface was exposed at the edge of the port. This is the most effective treatment result of the cleaning formula.

[0042] 3. Table 1 and Figure 5: Overall, the total nitrogen content of the waste liquid is low, and after a 10-fold dilution, it is below the detection limit. Although the total nitrogen content increases with the increase of the amount of hydrogen fluoride ammonia used in the basic example 1, it is still at a low concentration level. Example 4, as a dilution of Example 1, has a total nitrogen content close to that of Example 1, indicating that dilution did not significantly change the nitrogen residue level of the waste liquid. Based on the data, it is speculated that the total nitrogen content is related to the slight decomposition of hydrogen fluoride ammonia in an acidic system, producing nitrogen-containing products, but the overall values ​​are all below 1 mg / L, so the waste liquid has little impact on the environment and is environmentally friendly.

[0043] Table 1 4. Table 2 and Figure 6: The total phosphorus content showed a significant upward trend with the increase of hydrogen fluoride ammonia dosage, but the total phosphorus content of the four formulations was all below 0.015 mg / L, and the total phosphorus content of Examples 1, 2 and 4 was below the trace level, which met the first-level discharge limit of total phosphorus (≤0.5 mg / L) in the "Integrated Wastewater Discharge Standard", indicating that the risk of phosphorus pollution to water bodies from the waste liquid is extremely low.

[0044] Table 2 The cleaning solution provided by this invention is suitable for cleaning ordinary steel pipes (stainless steel) and steel pipes with different degrees of contamination. It can be used for batch processing, is easy to operate, and the cleaning solution can be reused. Compared with traditional cleaning methods, it has significant advantages in terms of efficiency, quality, cost and environmental protection.

[0045] Therefore, this patent proposes that the best solution for treating steel pipe surface contaminants using a mixed solution of ammonium bifluoride is to select and combine formulas according to the different degrees of contamination of the steel pipe.

[0046] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A steel pipe cleaning mixture, characterized in that, It is a compound made of nitric acid, ammonium hydrogen fluoride, sodium sulfate, hydroxyethylidene diphosphate, pyridine propane sulfonate, brightener, emulsifier and water.

2. The steel pipe cleaning mixture according to claim 1, characterized in that, The components are proportioned as follows by weight: 306 parts nitric acid, 5-15 parts ammonium hydrogen fluoride, 6 parts sodium sulfate, 3 parts hydroxyethylidene diphosphate, 1.5 parts pyridinium propane sulfonate, 5 parts brightener, 3 parts emulsifier, and 660.5-670.5 parts water, with a total of 1000 parts.

3. The steel pipe cleaning mixture according to claim 1, characterized in that, The mass ratio of each component by weight is as follows: 306 parts nitric acid, 5 parts ammonium hydrogen fluoride, 6 parts sodium sulfate, 3 parts hydroxyethylidene diphosphate, 1.5 parts pyridine propane sulfonate, 5 parts brightener, 3 parts emulsifier, and 670.5 parts water.

4. The steel pipe cleaning mixture according to claim 1, characterized in that, The components are proportioned as follows by weight: 306 parts nitric acid, 10 parts ammonium hydrogen fluoride, 6 parts sodium sulfate, 3 parts hydroxyethylidene diphosphate, 1.5 parts pyridinium propane sulfonate, 5 parts brightener, 3 parts emulsifier, and 665.5 parts water, totaling 1000 parts.

5. The steel pipe cleaning mixture according to claim 1, characterized in that, The components are proportioned as follows by weight: 306 parts nitric acid, 15 parts ammonium hydrogen fluoride, 6 parts sodium sulfate, 3 parts hydroxyethylidene diphosphate, 1.5 parts pyridinium propane sulfonate, 5 parts brightener, 3 parts emulsifier, and 660.5 parts water, totaling 1000 parts.

6. The steel pipe cleaning mixture according to claim 1, characterized in that, The brightener is KM0203.

7. The steel pipe cleaning mixture according to claim 1, characterized in that, The emulsifier is emulsifier OP-10.

8. The method for preparing the steel pipe cleaning mixed solution according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Pour the weighed water into a mixing container, and slowly add nitric acid along the container wall (do not pour water into nitric acid to avoid the strong acid dilution releasing heat and splashing), stirring gently while adding until well mixed; Step 2: Add ammonium hydrogen fluoride and sodium sulfate in sequence, stirring for 2-3 minutes after each addition until the solid is completely dissolved and there are no particles remaining; Step 3: Continue to add hydroxyethylidene diphosphate, pyridinium propanesulfonate, brightener, and emulsifier, stirring for 1-2 minutes after each addition to ensure that the additives are fully mixed with the solution; Step 4: After all components have been added, stir continuously with a glass rod for 10-15 minutes to obtain a homogeneous and transparent cleaning mixture solution.

9. A method for cleaning contaminants from the surface of a steel pipe, characterized in that, Includes the following steps: Step 1: Place the steel pipe cleaning solution according to any one of claims 1-7 into the cleaning tank, and then immerse the steel pipe to be cleaned in the steel pipe cleaning solution for a period of time; Step 2: After cleaning, take out the steel pipe, rinse it with clean water, and let it air dry.

10. The method according to claim 9, characterized in that, Soaking time is 15-60 minutes.

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