Reagent for removing residual nickel in anodic oxidation dyeing of aluminum alloy and preparation method of reagent

Abstract

The invention relates to a nickel removing agent and a preparation method thereof. Pollution-free organic acid and a complexing agent are used as nickel removing agents, and nickel hydrate in micropores can be effectively dissolved; meanwhile, an organic monomer which is easy to polymerize in an alkaline environment is added and polymerizes at local alkaline micropores formed by dissolving nickel hydrate to form a mesh, so that the corrosion resistance and the dyeing effect of the nickel-removed aluminum material are prevented from being reduced; in addition, the preparation method is simple, the use cost is reduced, and the waste liquid does not contain phosphorus, fluorine and other elements, and is safe and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to a nickel remover for aluminum alloy materials and a preparation method thereof. Background Art

[0002] With the widespread application of aluminum alloy materials in the fields of aviation, automobiles, electronics, etc., the importance of its surface treatment technology has become increasingly prominent. Among them, anodizing technology has become one of the most commonly used surface treatment methods because it can improve the corrosion resistance, decorativeness and mechanical properties of aluminum alloys. After anodizing, nickel salts (such as nickel acetate) are usually used for sealing to further enhance the stability of the oxide film. However, nickel hydrates or nickel compounds will remain on the surface and in the pores of the oxide film during the sealing process. These residues may not only cause potential harm to the environment and human health, but may also affect the performance of the oxide film. Therefore, it is necessary to remove these nickel components through a nickel remover. At present, common nickel remover technology has been described in many patents. For example, patent No. JP7101972B2 mentions the removal of nickel compounds by a solution containing vanadium compounds. This method can effectively reduce the residue of nickel ions and simultaneously form a protective film through the reaction of vanadium compounds with aluminum to avoid the destruction of the oxide film. However, the raw material cost of the vanadium compounds used in this process is high and the toxicity is strong, which is not conducive to large-scale industrial application. Another patent mentions the use of acidic solutions (such as nitric acid or hydrochloric acid) to dissolve nickel compounds. This type of method has high processing efficiency, but strong acids will corrode the oxide film, affecting the performance of the aluminum alloy dyeing layer, and there are also environmental and safety risks. Therefore, the existing technology still has a lot of room for improvement in terms of environmental protection, cost control and processing efficiency, and the development of new nickel removers is particularly necessary. New nickel removers need to meet the following requirements: First, comply with environmental protection regulations and reduce the use of harmful substances; second, protect the corrosion resistance, color resistance and mechanical properties of the oxide film; third, improve processing efficiency to meet the needs of industrial production; fourth, reduce production and use costs. Therefore, in response to the above problems, this patent proposes an environmentally friendly nickel remover for aluminum alloy materials and a preparation method thereof. Summary of the Invention

[0003] The main purpose of the present invention is to solve the problems of existing nickel removers, such as high pollution, corrosion to aluminum materials, and degradation of aluminum alloy properties, thereby providing an environmentally friendly nickel remover for aluminum alloy materials and a preparation method thereof. The nickel remover can effectively dissolve nickel hydrates in micropores while preventing a decrease in the corrosion resistance and dyeing effect of the aluminum material after nickel removal. The preparation method of the present invention is simple, the waste liquid does not contain elements such as phosphorus and fluorine, and is safe and environmentally friendly, making it suitable for large-scale industrial production.

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions.

[0005] The first aspect of the present invention provides a nickel removal agent, characterized in that the weight percentages of the constituent raw materials are:

[0006]

[0007] Preferably, the organic acid is one or more of acetic acid, citric acid, lactic acid, tartaric acid, succinic acid, malic acid, and fumaric acid.

[0008] Preferably, the complexing agent is one or more of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentaacetic acid, triethanolamine, glycine and sodium salts thereof.

[0009] Preferably, the surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, dodecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

[0010] Preferably, the polymerizable monomer is one or more of dopamine, acrylamide, ethyl acrylate, and methyl methacrylate.

[0011] Preferably, the corrosion inhibitor is one or more of sodium molybdate, sodium silicate, benzotriazole and its derivatives, and siloxane ketone.

[0012] A second aspect of the present invention provides a method for preparing the nickel removal agent, comprising the following steps:

[0013] (1) Add 2 / 3 of the required amount of water into a reaction vessel and heat to 40-60°C;

[0014] (2) adding organic acid, complexing agent, surfactant, polymerization monomer and the remaining amount of water in order according to the mass ratio;

[0015] (3) The pH value was adjusted to 6-7, and stirring was continued for 10-20 minutes to obtain the nickel removal agent.

[0016] The present invention has the following beneficial effects compared to the prior art:

[0017] (1) The present invention uses a pollution-free, low-corrosive organic acid to dissolve nickel hydrate to remove nickel from the surface of the complexing agent, and effectively stabilizes the free nickel ions after dissolution through the complexing agent to prevent the nickel ions from re-precipitating. In order to avoid the adverse effects of the nickel hydrate in the micropores on the corrosion resistance and sealing effect of the aluminum alloy surface after dissolution, this patent innovatively adds polymer monomers to the nickel remover. Nickel hydrate consumes hydrogen ions near the micropores during the dissolution process, thereby forming a local area with a higher pH value. By adding monomer molecules that are easily polymerized in an alkaline environment, a local network polymer film can be formed on the surface of the micropores while the nickel hydrate is dissolved, thereby effectively sealing the micropores, inhibiting color flow, and significantly improving local corrosion resistance. At the same time, the selective polymerization of monomer molecules in the local micropores can also avoid interference with the overall performance of the aluminum alloy surface.

[0018] (2) In addition, the preparation method of the present invention is simple, and the nickel remover can be obtained by simple preparation. Moreover, the nickel remover prepared by the present invention has excellent treatment effect, is non-corrosive, and does not produce pollutants such as phosphorus and fluorine. It has great practical value and is suitable for industrial large-scale production. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1

[0021] A nickel removal agent, the preparation method of which comprises the following steps:

[0022] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0023] Example 2

[0024] A nickel removal agent, the preparation method of which comprises the following steps:

[0025] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 20%, 10%, 12%, 6%, and 8% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0026] Example 3

[0027] A nickel removal agent, the preparation method of which comprises the following steps:

[0028] Heat 100g of water to 55°C, add acetic acid, triethanolamine, dodecyltrimethylammonium bromide, ethyl acrylate, and sodium silicate in a mass ratio of 15%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0029] Example 4

[0030] A nickel removal agent, the preparation method of which comprises the following steps:

[0031] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 6, and stir for 15 minutes.

[0032] Comparative Example 1

[0033] A nickel removal agent, the preparation method of which comprises the following steps:

[0034] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 10%, 10%, 0%, and 6% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0035] Comparative Example 2

[0036] A nickel removal agent, the preparation method of which comprises the following steps:

[0037] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 5%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0038] Comparative Example 3

[0039] A nickel removal agent, the preparation method of which comprises the following steps:

[0040] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 3%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 7, and stir for 15 minutes.

[0041] Comparative Example 4

[0042] A nickel removal agent, the preparation method of which comprises the following steps:

[0043] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 8, and stir for 15 minutes.

[0044] Comparative Example 5

[0045] A nickel removal agent, the preparation method of which comprises the following steps:

[0046] Heat 100g of water to 55°C, add citric acid, disodium edetate, sodium dodecylbenzenesulfonate, acrylamide, and sodium silicate in a mass ratio of 15%, 10%, 10%, 4%, and 6% and mix, add the remaining water, adjust the pH to 5, and stir for 15 minutes.

[0047] Verification Example 1

[0048] The nickel removal agents prepared in Examples 1-4 and Comparative Examples 1-5 were used to treat aluminum alloy workpieces. The nickel residue, color difference before and after treatment, and corrosion resistance were evaluated. These tests were performed using conventional methods and equipment in the art. The test indicators and results are shown in Tables 1 and 2 below.

[0049] Table 1 Test items and related indicators

[0050]

[0051] Table 2 Physical and chemical property test results of Examples 1-4 and Comparative Examples 1-5

[0052]

[0053]

[0054] It can be seen from the above results that the nickel remover material prepared by the embodiment of the present invention is significantly better than the comparative example in terms of nickel removal effect, aluminum corrosion resistance, and color difference before and after treatment. The main reason is that the present invention uses an organic acid and a complexing agent to jointly remove nickel hydrates on the surface of the aluminum material, which is both efficient and safe and pollution-free. At the same time, a monomer that is easily polymerized under alkaline conditions is innovatively added to the nickel remover, which can form a network of polymers in the local alkaline area formed by the dissolution of nickel hydrates, thereby improving the corrosion resistance of the aluminum material and reducing the effect of nickel removal on the surface properties of the aluminum material.

[0055] No polymerized monomer is added to the nickel remover prepared in Comparative Example 1, so the corrosion time of the aluminum alloy treated with this reagent is shorter and the corrosion resistance is significantly reduced. At the same time, since the micropores generated by the dissolution of nickel hydrate are not filled with polymer, the dye enclosed in the micropores is easily dissolved and faded, so there is a greater color difference; the amount of organic acid in the nickel remover prepared in Comparative Example 2 is not within the required range, resulting in the failure to completely dissolve the nickel hydrate on the surface of the aluminum alloy, and the nickel removal effect is significantly worse than that of the embodiment; the amount of complexing agent added to the nickel remover in Comparative Example 3 is too low, resulting in the dissolved nickel ions being easily re-precipitated on the surface of the aluminum material due to the high pH, ​​which in turn leads to poor nickel removal effect; the pH of the nickel remover in Comparative Example 4 is 8, and the alkalinity is too strong, resulting in the inability of the monomer to selectively polymerize on the surface of the aluminum material, and then a layer of polymer film is covered on the surface of the aluminum material, affecting the color of the aluminum alloy; the pH of the nickel remover in Comparative Example 5 is 5, and the acidity is too strong, resulting in difficulty in polymerizing the monomer. Similar to Comparative Example 1, the corrosion resistance is reduced and the color difference is large.

[0056] The above detailed description of the analytical methods involved in the present invention provides a detailed introduction. It should be noted that the above description is intended solely to help those skilled in the art better understand the methods and concepts of the present invention, and is not intended to limit the relevant content. Without departing from the principles of the present invention, those skilled in the art may make appropriate adjustments or modifications to the present invention, and such adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A nickel remover for aluminum alloy materials, characterized in that: The weight percentages of the constituent raw materials are:

2. The nickel removing agent for aluminum alloy material according to claim 1, characterized in that: The organic acid is one or more of acetic acid, citric acid, lactic acid, tartaric acid, succinic acid, malic acid and fumaric acid.

3. The nickel removing agent for aluminum alloy material according to claim 1, characterized in that: The complexing agent is one or more of ethylenediaminetetraacetic acid, citric acid, diethylenetriaminepentaacetic acid, triethanolamine, glycine and sodium salt thereof.

4. The nickel removing agent for aluminum alloy material according to claim 1, characterized in that: The surfactant is one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, dodecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

5. The nickel removing agent for aluminum alloy material according to claim 1, characterized in that: The polymerizable monomer is one or more of dopamine, acrylamide, ethyl acrylate and methyl methacrylate.

6. The nickel removing agent for aluminum alloy material according to claim 1, characterized in that: The corrosion inhibitor is one or more of sodium molybdate, sodium silicate, benzotriazole and its derivatives, and siloxane ketone.

7. The method for preparing the nickel remover according to any one of claims 1 to 6, wherein: The steps include: (1) Add 2 / 3 of the required amount of water into a reaction vessel and heat to 40-60°C; (2) adding organic acid, complexing agent, surfactant, polymerization monomer and the remaining amount of water in order according to the mass ratio; (3) The pH value was adjusted to 6-7, and stirring was continued for 10-20 minutes to obtain the nickel removal agent.

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