Efficient and low-corrosivity ash removal agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of metal surface treatment, and discloses an efficient and low-corrosivity ash removal agent as well as a preparation method and application thereof. The ash removal agent comprises the following components: organic acid, an oxidizing agent, organic amine ester TPP, methylbenzotriazole, polyaspartic acid, a complexing agent, a nonionic surfactant and water. The ash removal agent is high in ash removal efficiency and small in corrosion to an aluminum (alloy) matrix, and meanwhile, the ash removal agent does not contain nitric acid, chromic anhydride and other ammonia nitride components which severely pollute the environment.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment technology, and specifically relates to a high-efficiency, low-corrosion desiccant, its preparation method, and its application. Background Technology

[0002] In the field of aluminum (alloy) surface treatment, there are two important pretreatment processes: alkaline etching and acid-coating polishing. Alkaline etching is a crucial step in removing the loose natural oxide film layer from the aluminum (alloy) surface and adjusting surface roughness, while acid-coating polishing can simultaneously achieve surface smoothing and gloss enhancement. However, both pretreatment processes trigger complex side reactions involving the selective dissolution of elements in the aluminum (alloy) that are not easily corroded, such as manganese, copper, silicon, and iron. When the aluminum is corroded, insoluble metals such as manganese, copper, silicon, and iron, along with their intercalation compounds (e.g., Al₂Cu, Mg₂Si), are exposed and adhere to the substrate surface in particle form, forming a dense layer of ash. This ash has a complex composition and is difficult to remove completely with conventional cleaning. Incomplete ash removal can lead to a series of problems in the subsequent anodic oxide film, such as rainbow patterns, marks, localized failure to form a film, and uneven coloring, severely affecting the surface quality of the product. Furthermore, the ash that is not thoroughly cleaned and carried into the oxidation tank can result in poor oxide film quality and shorten the service life of the oxidation tank.

[0003] To address the persistent ash buildup problem in aluminum (alloy) pretreatment processes, the commonly used ash removal technologies are the nitric acid method and the sulfuric acid method. The traditional nitric acid method primarily utilizes the strong oxidizing and dissolving properties of nitric acid to remove ash. This process can remove almost all types of ash, but it has significant drawbacks: nitric acid easily decomposes to produce nitrogen oxides, polluting the environment, and it severely corrodes the aluminum (alloy) matrix, easily leading to over-corrosion. The sulfuric acid + chromic anhydride method is more environmentally friendly than the nitric acid method, and chromic anhydride is less prone to decomposition and relatively more stable. However, it carries the risk of hexavalent chromium pollution, and wastewater treatment is more complex. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the purpose of the present invention is to provide a highly efficient, low-corrosion ash remover, its preparation method, and its application. The ash remover of the present invention, through the synergistic effect between its components, achieves high ash removal efficiency and low corrosivity to the aluminum (alloy) matrix, while also not containing components such as nitric acid and chromic anhydride, which are highly polluting to the environment.

[0005] In a first aspect, the present invention provides a desiccant comprising the following components: an organic acid, an oxidizing agent, an organic amine ester TPP, methylbenzotriazole, polyaspartic acid, a complexing agent, a nonionic surfactant, and water.

[0006] In some embodiments of the present invention, the organic acid includes phytic acid and oxalic acid.

[0007] In some embodiments of the present invention, the oxidant includes hydrogen peroxide.

[0008] In some embodiments of the present invention, the complexing agent includes tetrasodium diglutamate.

[0009] In some embodiments of the present invention, the nonionic surfactant includes isomeric tridecyl alcohol polyoxyethylene ether.

[0010] In some embodiments of the present invention, the desiccant, by weight percentage, comprises the following components: 10-20% phytic acid, 5-20% oxalic acid, 8-12% hydrogen peroxide, 10-18% organic amine ester TPP, 1-5% methylbenzotriazole, 1-6% polyaspartic acid, 1-3% tetrasodium glutamate diacetate, 1-3% isotridecyl alcohol polyoxyethylene ether, and the balance being water. The phytic acid is preferably 15-20%. The oxalic acid is preferably 15-20%. The hydrogen peroxide is preferably 10-12%. The organic amine ester TPP is preferably 15-18%. The methylbenzotriazole is preferably 4-5%. The polyaspartic acid is preferably 5-6%. The tetrasodium glutamate diacetate is preferably 2-3%. The isotridecyl alcohol polyoxyethylene ether is preferably 2-3%.

[0011] Specifically, the phytic acid in the descaling agent of this invention, also known as inositol hexaphosphate, is a cyclic polyol phosphate ester that reacts with Al... 3+ It has an exceptionally strong chelating ability. The phosphate and hydroxyl groups in phytic acid can bind with Al. 3+ Ca 2+ Mg 2+ Phytic acid combines with metal ions to form stable complexes, thereby reducing the activity of the metal ions and acting as a stabilizer in this descaling agent. Simultaneously, phytic acid can block the electrochemical corrosion pathway by chelating free metal ions, and its antioxidant properties can inhibit the regeneration of scale and effectively decompose the metal oxide film.

[0012] Specifically, the oxalic acid in the ash removal agent of this invention dissolves the alumina film on the surface of the aluminum (alloy) substrate under acidic conditions. Simultaneously, its synergistic effect with phytic acid enhances the removal efficiency of silicon particles, thereby improving ash removal efficiency. Compared to other organic acids such as tartaric acid and citric acid, phytic acid and oxalic acid have a wider range and stronger metal complexing ability and acidity, exhibiting a more significant removal effect on some alkaline deposits and accelerating the detachment of ash after alkaline etching. Furthermore, phytic acid possesses stronger metal complexing stability, inhibiting the decomposition of hydrogen peroxide and forming a dense monomolecular protective film that provides a certain degree of metal corrosion inhibition.

[0013] Specifically, the organic amine ester TPP in the descaling agent of the present invention has an amine ester group in its molecular structure that can react with Fe. 3+ Cu 2+ When metal ions form stable complexes, they can simultaneously dissolve the oxide scale on the metal surface and disperse the dirt particles, achieving chemical removal of the oxide scale. At the same time, TPP can also adsorb onto the metal surface in acidic systems to form a protective film, inhibiting corrosion reactions and improving corrosion inhibition.

[0014] Specifically, the hydrogen peroxide in the ash removal agent of this invention acts as an oxidant, oxidizing and decomposing oxidized ash, accelerating the dissolution of the ash film. Simultaneously, the phytic acid's shielding effect on metal ion catalysis stabilizes and inhibits the decomposition of hydrogen peroxide by metal ions, enhancing the stripping effect of hydrogen peroxide on metal oxides and improving the ash removal efficiency. Hydrogen peroxide decomposes to produce only water and oxygen, while persulfate generates sulfates, increasing the difficulty and cost of wastewater treatment.

[0015] Specifically, the methylbenzotriazole in the ash remover of the present invention forms a dense adsorption film on the surface of aluminum (alloy) through the lone pair electrons of nitrogen atoms, thereby inhibiting the pitting corrosion tendency of aluminum (alloy) during the ash removal process.

[0016] Specifically, the polyaspartic acid in the ash remover of this invention inhibits localized metal corrosion and reduces the corrosion rate of the metal through carboxyl complexation, while preventing oxide scale redeposition. When used in conjunction with methylbenzotriazole, it can improve ash removal efficiency while reducing corrosion to the base metal.

[0017] Specifically, the tetrasodium diacetate of glutamic acid in the ash remover of this invention contains a tetraacetic acid group, which can efficiently complex Ca... 2+ Mg 2+ Metal ions soften water and reduce the impact of impurities such as calcium and magnesium ions on the ash removal tank solution, thus extending its service life.

[0018] Specifically, the isomeric tridecyl alcohol polyoxyethylene ether in the ash remover of this invention is a nonionic surfactant that can reduce the surface tension of the solution and enhance the wetting and penetration ability of the ash remover on hydrophobic ash particles; it also has excellent detergency and antistatic properties, which can eliminate the static charge between the ash particles and the metal surface and weaken the electrostatic attraction between the ash particles and the metal surface. When used in combination with organic amine ester TPP, it can enhance its dissolution effect on metal particle ash particles and improve the ash removal efficiency.

[0019] A second aspect of the present invention provides a method for preparing the ash removal agent described in the first aspect of the present invention, comprising the following steps: The components are mixed to obtain the ash remover.

[0020] A third aspect of the present invention provides a method for removing ash from metallic materials, comprising removing ash from the metallic materials using the ash-removing agent described in the first aspect of the present invention.

[0021] In some embodiments of the present invention, the ash removal method includes the following steps: The ash removal agent is mixed with water to obtain the ash removal tank solution; The metal material is immersed in the ash removal tank solution at room temperature.

[0022] In some embodiments of the present invention, the metallic material includes an aluminum-based material.

[0023] In some embodiments of the present invention, the aluminum-based material includes at least one of aluminum metal materials and aluminum alloy materials.

[0024] In some embodiments of the present invention, the concentration of the ash removal agent in the ash removal tank liquid is 100-120 g / L.

[0025] In some embodiments of the present invention, the soaking time at room temperature is 1-3 minutes; preferably 2-3 minutes.

[0026] Specifically, the ash removal refers to removing the ash-like substances that have adhered to the surface of the aluminum-based material after steps such as degreasing, water washing, alkaline etching / chemical polishing.

[0027] A fourth aspect of the present invention provides the application of the desiccant described in the first aspect of the present invention in the surface treatment of aluminum-based materials.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The ash removal agent of the present invention mainly provides an acidic system with phytic acid and oxalic acid, and does not contain strong acids such as sulfuric acid, nitric acid, and hydrofluoric acid, nor does it contain compounds such as chromium anhydride, thus eliminating the possibility of pollution from ammonia nitrogen and hexavalent chromium; the selected components are more in line with environmental protection requirements, and the wastewater discharge treatment is simple.

[0029] (2) The ash removal agent of this invention is a compound of phytic acid, hydrogen peroxide, and organic amine ester TPP, which synergistically improves the ash removal efficiency. Phytic acid blocks the electrochemical corrosion path through chelation, and at the same time, phytic acid can effectively inhibit the decomposition of hydrogen peroxide, so that hydrogen peroxide can continuously and stably exert its oxidative stripping effect under the protection of phytic acid. TPP can disperse the ash and, with the assistance of the nonionic surfactant isomeric tridecyl alcohol polyoxyethylene ether, accelerate the dissolution of the ash, thereby enabling rapid ash removal.

[0030] (3) The ash remover of the present invention adds methylbenzotriazole and polyaspartic acid as a composite corrosion inhibitor. It utilizes the dual protective effects of adsorption film formation and complexation to inhibit corrosion, effectively reducing the corrosion rate of the substrate. At the same time, it works synergistically with tetrasodium diacetate of glutamic acid to reduce the concentration of metal ions in the ash removal tank, further reducing the corrosivity. Detailed Implementation

[0031] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments can be obtained from conventional commercial sources or by existing technical methods. Unless otherwise specified, the experimental or testing methods are conventional methods in the art.

[0032] In this invention, room temperature refers to 25±2℃.

[0033] Example 1 A desiccant is composed of the following components by weight percentage: 10% phytic acid, 10% hydrogen peroxide, 10% organic amine ester TPP, 5% oxalic acid, 1% methylbenzotriazole, 1% polyaspartic acid, 1% tetrasodium glutamate diacetate, 1% isotridecyl alcohol polyoxyethylene ether, and the balance being deionized water.

[0034] The ash remover in this embodiment is prepared by mixing the components and stirring them thoroughly to dissolve them.

[0035] Example 2 A desiccant is composed of the following components by weight percentage: 20% phytic acid, 10% hydrogen peroxide, 10% organic amine ester TPP, 10% oxalic acid, 3% methylbenzotriazole, 3% polyaspartic acid, 3% tetrasodium glutamate diacetate, 1% isotridecyl alcohol polyoxyethylene ether, and the balance being deionized water.

[0036] The ash remover in this embodiment is prepared by mixing the components and stirring them thoroughly to dissolve them.

[0037] Example 3 A ash remover comprises the following components by weight percentage: 20% phytic acid, 10% hydrogen peroxide, 15% organic amine ester TPP, 15% oxalic acid, 4% methylbenzotriazole, 5% polyaspartic acid, 2% tetrasodium diacetate of glutamic acid, 3% isotridecyl alcohol polyoxyethylene ether, and the balance being deionized water.

[0038] The ash remover in this embodiment is prepared by mixing the components and stirring them thoroughly to dissolve them.

[0039] Example 4 A ash remover comprises the following components by weight percentage: 20% phytic acid, 10% hydrogen peroxide, 18% organic amine ester TPP, 20% oxalic acid, 5% methylbenzotriazole, 6% polyaspartic acid, 2% tetrasodium glutamate diacetate, 3% isotridecyl alcohol polyoxyethylene ether, and the balance being deionized water.

[0040] The ash remover in this embodiment is prepared by mixing the components and stirring them thoroughly to dissolve them.

[0041] Comparative Example 1 The only difference from Example 1 is that phytic acid and oxalic acid are replaced with tartaric acid in equal amounts, while the other components, contents and preparation methods are the same as in Example 1.

[0042] Comparative Example 2 The only difference from Example 1 is that hydrogen peroxide is replaced with an equal amount of sodium persulfate, while the other components, contents, and preparation methods are the same as in Example 1.

[0043] Comparative Example 3 The only difference from Example 1 is that the organic amine ester TPP is missing; the other components, contents, and preparation methods are the same as in Example 1.

[0044] Comparative Example 4 The only difference from Example 1 is that isomeric tridecyl alcohol polyoxyethylene ether is replaced with sodium dodecylbenzenesulfonate in equal amounts, while the other components, contents and preparation methods are the same as in Example 1.

[0045] Comparative Example 5 The only difference from Example 1 is that methylbenzotriazole is missing; the other components, contents, and preparation methods are the same as in Example 1.

[0046] Comparative Example 6 The only difference from Example 1 is that polyaspartic acid is missing; the other components, contents, and preparation methods are the same as in Example 1.

[0047] Comparative Example 7 The only difference from Example 1 is that it lacks tetrasodium diglutamate diacetate; the other components, contents, and preparation methods are the same as in Example 1.

[0048] Experiment Example 1: Ash Removal Effect Test In Experiment 1, the ash removers obtained from Examples 1-4 and Comparative Examples 1-7 were used to remove ash from aluminum materials (sandblasting material for solar cell frames, model 6005).

[0049] The aluminum material used for the dust removal process has undergone alkaline etching and other treatments. The specific preparation includes the following steps: (1) Degreasing: Place the aluminum material in a 20g / L solution of acidic degreasing agent (LW-16 aluminum bright cleaning agent from Foshan Haihua Surface Treatment Technology Co., Ltd.) and treat it for 4 minutes at room temperature to remove grease, dust and other contaminants from the surface of the aluminum material. After degreasing, rinse the aluminum material in at least two water washing tanks to clean the degreasing agent components from the surface of the aluminum material so as to avoid contaminating the tank solution in the next process.

[0050] (2) Alkali etching: After degreasing, the aluminum material is placed in an alkaline etching bath containing 60g / L sodium hydroxide, 60g / L aluminum ions, and 25g / L alkaline etchant (LW-01 liquid alkaline etchant from Foshan Haihua Surface Treatment Technology Co., Ltd.) and treated at 45℃ for 4 minutes to remove the oxide film on the surface of the aluminum material and adjust the roughness of the aluminum material surface. After alkaline etching, the aluminum material needs to be washed with water at least twice to clean off the residual alkaline etching solution components on the surface of the aluminum material to prevent them from being carried into the bath of the next process.

[0051] Ash removal treatment: After the aluminum material is cleaned by alkaline etching water, put it into the ash removal tank solution containing 100g / L of ash removal agent and immerse it at room temperature for 1min-3min. During the process, you can gently shake the aluminum material. After ash removal, the aluminum material needs to be washed with water at least twice to remove the ash removal agent remaining on the surface of the aluminum material.

[0052] In Experiment 1, a total of 22 ash removal tests were conducted. Groups 1-11 were treated with the ash removal agents obtained in Examples 1-4 and Comparative Examples 1-7, respectively, and were immersed at room temperature for 1 minute. Groups 12-22 were treated with the ash removal agents obtained in Examples 1-4 and Comparative Examples 1-7, respectively, and were immersed at room temperature for 3 minutes.

[0053] The criteria for judging the ash removal effect of ash removal agents are as follows: (1) After washing with descaling water, visually inspect the surface under sunlight to see if it is bright, clean and free of dust; (2) Wipe the surface of the aluminum material with a clean white paper towel and observe whether there are any gray stains left on the paper towel surface; (3) Wipe the treated aluminum surface with a clean white cloth soaked in alcohol and observe whether there are any residues on the aluminum surface and the white cloth surface.

[0054] After the ash removal treatment, the surface condition of the aluminum materials obtained in each group of tests is shown in Tables 1 and 2. In Tables 1 and 2, the degree of yellow ash residue from most to least is as follows: obvious yellow ash residue > some yellow ash residue > small amount of yellow ash residue > slight yellow ash residue.

[0055] Table 1

[0056] Table 2

[0057] According to the results in Tables 1 and 2, the ash removal agent provided by the present invention has a better ash removal effect compared with the ash removal agents provided in Comparative Examples 1-7.

[0058] Test Example 2 Corrosion Test The standard for judging the corrosivity of the desiccant is as follows: use an aluminum alloy workpiece of type 6063 with dimensions of 50×25×60mm, and conduct the test according to GB / T8019-2007 "Metals and Alloys - Immersion Test".

[0059] The test results are shown in Table 3. The mass difference is calculated as follows: (Mass of the workpiece after cleaning and drying before immersion - Mass of the workpiece after cleaning and drying after immersion) / Area of ​​the workpiece, in μg / mm². 2 .

[0060] Table 3

[0061] As shown in Table 3, the ash remover provided by the present invention is less corrosive than the ash removers provided in Comparative Examples 1-7.

[0062] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A de-sooting agent, characterized in that, The descaling agent comprises the following components: organic acid, oxidizing agent, organic amine ester TPP, methyl benzotriazole, polyaspartic acid, complexing agent, non-ionic surfactant and water.

2. The ash remover according to claim 1, characterized in that, The organic acid comprises phytic acid and oxalic acid.

3. The ash remover according to claim 1, characterized in that, The oxidizing agent comprises hydrogen peroxide.

4. The ash remover according to claim 1, characterized in that, The complexing agent comprises tetrasodium glutamate diacetate.

5. The ash remover according to claim 1, wherein The non-ionic surfactant comprises isomeric tridecanol polyoxyethylene ether.

6. The ash remover according to claim 1, wherein The descaling agent consists of the following components in terms of mass percentage: phytic acid 10-20%, oxalic acid 5-20%, hydrogen peroxide 8-12%, organic amine ester TPP 10-18%, methyl benzotriazole 1-5%, polyaspartic acid 1-6%, tetrasodium glutamate diacetate 1-3%, isomeric tridecanol polyoxyethylene ether 1-3% and water in balance.

7. A method for the preparation of a deashing agent according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: The components are mixed to obtain the descaling agent.

8. A method of desmutting a metal material, characterized by, The method comprises descaling the metal material with the descaling agent according to any one of claims 1-6.

9. The ash removal method according to claim 8, characterized by, The method comprises the following steps: The descaling agent is mixed with water to obtain a descaling tank liquor; The metal material is immersed in the descaling tank liquor and soaked at room temperature.

10. Use of the descaling agent according to any one of claims 1-6 in surface treatment of aluminum-based materials.

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