Weakly acidic aluminum alloy ash removal bleaching agent and preparation method thereof

Abstract

The invention relates to a faintly acid aluminum alloy dedusting bleaching agent and a preparation method thereof, and belongs to the technical field of aluminum alloy surface treatment. Ammonium bifluoride and hydrofluoric acid are used as ion neutralizers, and the effective component of green tea is added, so that silicon ion black ash in the aluminum alloy can be efficiently neutralized, and the removal capacity of surface oxides and dirt is improved; due to introduction of sodium dodecyl sulfate and triton X-100, wetting and permeation of the solution on the surface of the aluminum alloy are further improved, and the treatment effect is promoted; by adding ethylene glycol, the stability and viscosity of the treating fluid are improved. The dedusting bleaching agent is prepared from a modified ion neutralizer, a stabilizer, an oxidizing agent, a complexing agent and deionized water according to a scientific ratio, so that the corrosivity to the aluminum alloy is reduced, the stability at normal temperature is ensured, effective complexing of metal ions and neutralization of ash are also realized, and efficient and green treatment on the surface of the aluminum alloy is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy surface treatment and relates to a weakly acidic aluminum alloy deashing bleaching agent and a preparation method thereof. Background Art

[0002] In the production process of aluminum alloys, the consumables used in the processing and the oxidation in the air often cause discoloration on the surface of the aluminum alloy. This problem is particularly prominent in die-cast aluminum alloy products, mainly manifested as uneven color difference in appearance.

[0003] The traditional method involves deashing and bleaching aluminum alloy products, which includes first alkaline or acid etching, followed by bleaching with strong acid bleaching agents such as nitric acid or chromic acid. However, these bleaching agents are not only extremely acidic, causing serious pollution to the production environment, but also pose a huge threat to the health of operators. In addition, they are also highly corrosive to the aluminum alloy products themselves, easily causing over-corrosion, thereby weakening the impact resistance of the products. Furthermore, for some aluminum alloy products with thinner thickness or products with extremely high dimensional accuracy requirements, this treatment method is very likely to lead to a large number of undesirable problems, seriously affecting the quality and reliability of the products. Therefore, it is urgent to develop a green, environmentally friendly and efficient aluminum alloy deashing and bleaching agent. Summary of the invention

[0004] The purpose of the present invention is to provide a weakly acidic aluminum alloy deashing and bleaching agent and a preparation method thereof, which has the characteristics of high-efficiency deashing and bleaching performance and green environmental protection.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A weakly acidic aluminum alloy deashing and bleaching agent, the deashing and bleaching agent has the following formula, in terms of weight percentage, 2-5% of stabilizer, 10-50% of oxidant, 10-15% of modified ion neutralizer, 2-5% of complexing agent, and the balance of deionized water.

[0007] Wherein, the preparation method of the modified ion neutralizer is as follows:

[0008] S1: ammonium bifluoride and hydrofluoric acid are mixed and dissolved in deionized water, and ultrasonically stirred for 30 minutes to obtain a solution A with a mass fraction of 50%;

[0009] S2: Mix green tea powder and deionized water in a mass ratio of 1:50, heat and stir at 70°C for 4 h, centrifuge at 4000-5000 rpm / min for 10 min, remove the precipitate and obtain solution B;

[0010] S3: Solution A and solution B are mixed in a volume ratio of (7-9):1, and stirred at a speed of 500-600 rpm / min for 1 h. Sodium dodecyl sulfate and Triton X-100 are mixed and added to the mixed solution of solution A and solution B, and stirring is continued for 30 min to obtain solution C;

[0011] S4: adding ethylene glycol in an amount of 5 wt % to solution C, ultrasonicating for 30 min, washing with deionized water and drying in a constant temperature drying oven at 60° C. for 12 h to obtain the modified ion neutralizer.

[0012] Furthermore, the stabilizer is one or two of phytic acid and polyethylene polyamine polyalkylene phosphonate.

[0013] Furthermore, the oxidant is one or more of hydrogen peroxide, sodium chlorate, and sodium hypochlorite.

[0014] Furthermore, the complexing agent is one or both of citric acid and ethylenediaminetetraacetic acid.

[0015] Furthermore, in S1, ammonium bifluoride and hydrofluoric acid are mixed in a mass ratio of 3:1.

[0016] Furthermore, in the S3, sodium dodecyl sulfate and Triton X-100 are mixed in a mass ratio of 1:1.

[0017] Furthermore, the ultrasonic power in S4 is 5 to 7 kHz.

[0018] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation process of the deashing and bleaching agent comprising: adding a stabilizer, an oxidant, a modified ion neutralizer, and a complexing agent into deionized water in sequence at room temperature according to a formula ratio, and mixing them for 30 minutes under stirring conditions to obtain the deashing and bleaching agent.

[0019] Furthermore, in the preparation method of the deashing bleaching agent, the stirring speed is 650-750 r / min.

[0020] As a fluorinating agent, ammonium bifluoride can provide fluoride ions, which form a protective film on the surface of aluminum alloy to prevent further corrosion of the aluminum alloy and help remove surface oxides and dirt. Hydrofluoric acid is highly corrosive and can quickly dissolve oxides on the surface of aluminum alloy. After being mixed with ammonium bifluoride in a certain mass ratio, its corrosiveness is controlled. At the same time, it effectively neutralizes silicon ion black ash in aluminum alloy material and has efficient ash removal ability.

[0021] Green tea powder is rich in antioxidant and antibacterial active ingredients such as tea polyphenols, which helps prevent the aluminum alloy surface from being over-oxidized during the treatment process and inhibits possible microbial contamination, ensuring the cleanliness and stability of the treatment process and the final product. The active ingredients are extracted from the green tea powder by heating and added to the modified ion neutralizer, which not only enriches the chemical composition of the ion neutralizer, but also significantly improves its biocompatibility as a natural extract, reducing the potential threat to the ecosystem and human health during use. In addition, the addition of green tea extract promotes the stability and solubility of the ion neutralizer in the treatment solution, helps to neutralize harmful ions more efficiently, and reduces the generation and emission of harmful substances during the treatment process.

[0022] Sodium dodecyl sulfate is an anionic surfactant with strong decontamination ability and good wetting properties. It can reduce the surface tension of the solution, making it easier for the deashing bleach to spread and penetrate into the tiny pores and cracks on the surface of the aluminum alloy, enhancing the wettability and permeability of the solution to the surface of the aluminum alloy, promoting the close contact between the effective ingredients such as fluoride and tea polyphenols in the neutralizer and the surface of the aluminum alloy, and significantly improving the treatment effect. Triton X-100 is a non-ionic surfactant with excellent emulsification, dispersion and penetration properties. It can destroy the binding force between the dirt and the surface of the aluminum alloy, making it easier to separate the dirt from the surface; at the same time, Triton X-100 can also form a thin wetting film on the surface of the aluminum alloy, which helps to maintain the uniform distribution and continuous action of the deashing bleach. Ethylene glycol can improve the stability of the ionic neutralizer in the application environment, and also help to increase the viscosity of the solution, making the treatment liquid easier to adhere to the surface of the aluminum alloy.

[0023] The addition of stabilizers in the formula ensures that the oxidant does not chemically decompose under normal temperature conditions; the oxidant uses substances such as hydrogen peroxide, which have good oxidizing ability and relatively weak corrosion to aluminum alloy materials; the addition of complexing agents can effectively complex the various metal ions produced by the deashing bleaching agent during operation, slow down the temperature rise rate of the deashing bleaching agent tank liquid, and ensure the maximum timeliness of the deashing bleaching agent tank liquid. The prepared aluminum alloy deashing bleaching agent can replace traditional nitric acid or chromic acid bleaching agents, avoiding the generation of a large amount of yellow toxic gas and harmful hexavalent chromium ions during bleaching; at the same time, the deashing bleaching agent avoids the use of dangerous strong acids, reduces operating risks, and ensures the health and safety of workers; in addition, the deashing bleaching agent exhibits extremely low corrosion to the surface of aluminum alloys, which not only extends the service life of aluminum alloy products, but also reduces losses in subsequent processing.

[0024] Beneficial effects of the present invention:

[0025] (1) Through the synergistic effect of ammonium bifluoride and hydrofluoric acid, the corrosion is effectively controlled while the silicon ions and black ash in the aluminum alloy are efficiently neutralized, significantly improving the ability to remove surface oxides and dirt; the addition of green tea powder further enhances the antioxidant and antibacterial properties of the ion neutralizer, preventing the overoxidation and microbial contamination of the aluminum alloy during the treatment process, ensuring the treatment effect and the cleanliness and stability of the product; the introduction of sodium dodecyl sulfate and Triton X-100 significantly improves the wettability and permeability of the solution to the aluminum alloy surface, promotes the close contact between the effective ingredients and the aluminum alloy surface, thereby enhancing the treatment effect; the addition of ethylene glycol improves the stability and viscosity of the treatment solution.

[0026] (2) A weakly acidic aluminum alloy deashing and bleaching agent is prepared by rationally mixing modified ion neutralizer, stabilizer, oxidant, chelating agent and deionized water, which ensures the stability of the deashing and bleaching agent at room temperature, reduces the corrosiveness to aluminum alloy, effectively chelates the metal ions generated during the treatment process, effectively neutralizes the ash, slows down the temperature rise rate of the bath liquid, prolongs the service life of the bath liquid, and realizes efficient and green treatment of the aluminum alloy surface. DETAILED DESCRIPTION

[0027] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with embodiments.

[0028] CAS / Article No. Manufacturer Phytate 83-86-3 Shanghai Kangtuo Chemical Co., Ltd. Hydrogen Peroxide 7722-84-1 Shanghai Aladdin Biochemical Technology Co., Ltd. Citric Acid 77-92-9 Hunan Dongting Citric Acid Chemical Co., Ltd. Ammonium bifluoride 1341-49-7 Huanggang Huayang Pharmaceutical Co., Ltd. Hydrofluoric acid 7664-39-3 Anhui Xuxin Chemical Co., Ltd. Green tea powder 94650-60-2 Shaanxi Jianchuang Biotechnology Co., Ltd. Sodium dodecyl sulfate 2386-53-0 Shanghai Aladdin Biochemical Technology Co., Ltd. Triton X-100 - Jiangsu Boquan Biotechnology Co., Ltd. Ethylene glycol 107-21-1 Shandong Mantanghong New Materials Co., Ltd.

[0029] Example 1

[0030] The formula 1 of the deashing bleaching agent is as follows: in terms of weight percentage, phytic acid 5%, hydrogen peroxide 50%, modified ion neutralizer 15%, citric acid 5%, and deionized water as the balance.

[0031] Wherein, the preparation method of the modified ion neutralizer is as follows:

[0032] S1: ammonium bifluoride and hydrofluoric acid were mixed in a mass ratio of 3:1 and dissolved in deionized water, and ultrasonically stirred for 30 minutes to obtain a solution A with a mass fraction of 50%;

[0033] S2: Mix green tea powder and deionized water in a mass ratio of 1:50, heat and stir at 70°C for 4 h, centrifuge at 4000 rpm / min for 10 min, remove the precipitate and obtain solution B;

[0034] S3: Solution A and solution B were mixed in a volume ratio of 7:1, stirred at a speed of 500 rpm / min for 1 h, sodium dodecyl sulfate and Triton X-100 were mixed in a mass ratio of 1:1 and added to the mixed solution of solution A and solution B, wherein the addition amount of the mixture of sodium dodecyl sulfate and Triton X-100 was 5 wt%, and stirring was continued for 30 min to obtain solution C;

[0035] S4: adding ethylene glycol in an amount of 5 wt % to solution C, ultrasonicating for 30 min at an ultrasonic power of 5 kHz, washing with deionized water and drying in a constant temperature drying oven at 60° C. for 12 h to obtain the modified ion neutralizer.

[0036] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation method of the deashing and bleaching agent comprising the following steps: according to formula 1, inositol hexaphosphate, hydrogen peroxide, a modified ion neutralizer, and citric acid are sequentially added into deionized water at room temperature, and mixed for 30 minutes under a stirring condition of 650 r / min to obtain the deashing and bleaching agent.

[0037] Example 2

[0038] The formula 2 of the deashing bleaching agent is as follows: in terms of weight percentage, phytic acid 4.5%, hydrogen peroxide 40%, modified ion neutralizer 14%, citric acid 4.5%, and deionized water the remainder.

[0039] Wherein, the preparation method of the modified ion neutralizer is as follows:

[0040] S1: ammonium bifluoride and hydrofluoric acid were mixed in a mass ratio of 3:1 and dissolved in deionized water, and ultrasonically stirred for 30 minutes to obtain a solution A with a mass fraction of 50%;

[0041] S2: Green tea powder and deionized water were mixed in a mass ratio of 1:50, heated and stirred at 70°C for 4 h, and centrifuged at 4500 rpm / min for 10 min using a high-speed centrifuge to remove the precipitate to obtain solution B;

[0042] S3: Solution A and solution B were mixed in a volume ratio of 8:1, stirred at a speed of 550 rpm / min for 1 h, sodium dodecyl sulfate and Triton X-100 were mixed in a mass ratio of 1:1 and added to the mixed solution of solution A and solution B, wherein the addition amount of the mixture of sodium dodecyl sulfate and Triton X-100 was 5 wt%, and stirring was continued for 30 min to obtain solution C;

[0043] S4: adding ethylene glycol in an amount of 5 wt % to solution C, ultrasonicating for 30 min at an ultrasonic power of 6 kHz, washing with deionized water and drying in a constant temperature drying oven at 60° C. for 12 h to obtain the modified ion neutralizer.

[0044] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation method of the deashing and bleaching agent comprising the following steps: according to formula 2, inositol hexaphosphate, hydrogen peroxide, a modified ion neutralizer, and citric acid are sequentially added into deionized water at room temperature, and mixed for 30 minutes under stirring conditions of 700 r / min to obtain the deashing and bleaching agent.

[0045] Example 3

[0046] The formula 3 of the deashing bleaching agent is as follows: in terms of weight percentage, phytic acid 2%, hydrogen peroxide 30%, modified ion neutralizer 12%, citric acid 4%, and deionized water as the balance.

[0047] Wherein, the preparation method of the modified ion neutralizer is as follows:

[0048] S1: ammonium bifluoride and hydrofluoric acid were mixed in a mass ratio of 3:1 and dissolved in deionized water, and ultrasonically stirred for 30 minutes to obtain a solution A with a mass fraction of 50%;

[0049] S2: Mix green tea powder and deionized water in a mass ratio of 1:50, heat and stir at 70°C for 4 h, centrifuge at 5000 rpm / min for 10 min, remove the precipitate and obtain solution B;

[0050] S3: Solution A and Solution B were mixed in a volume ratio of 9:1, and stirred at a speed of 600 rpm / min for 1 h. Sodium dodecyl sulfate and Triton X-100 were mixed in a mass ratio of 1:1 and added to the mixed solution of Solution A and Solution B, wherein the addition amount of the mixture of sodium dodecyl sulfate and Triton X-100 was 5 wt %. Stirring was continued for 30 min to obtain Solution C;

[0051] S4: adding ethylene glycol in an amount of 5 wt % to solution C, ultrasonicating for 30 min at an ultrasonic power of 7 kHz, washing with deionized water and drying in a constant temperature drying oven at 60° C. for 12 h to obtain the modified ion neutralizer.

[0052] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation method of the deashing and bleaching agent comprising the following steps: according to formula 3, inositol hexaphosphate, hydrogen peroxide, a modified ion neutralizer, and citric acid are sequentially added into deionized water at room temperature, and the mixture is mixed for 30 minutes under a stirring condition of 750 r / min to obtain the deashing and bleaching agent.

[0053] Example 4

[0054] The formula 4 of the deashing bleaching agent is as follows: in terms of weight percentage, 3% of phytic acid, 20% of hydrogen peroxide, 11% of a modified ion neutralizer, 3% of citric acid, and the balance is deionized water.

[0055] The preparation process of the modified ion neutralizer is consistent with that of Example 1.

[0056] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation method of the deashing and bleaching agent comprises the following steps: according to formula 4, inositol hexaphosphate, hydrogen peroxide, a modified ion neutralizer, and citric acid are sequentially added into deionized water at room temperature, and the mixture is mixed for 30 minutes under a stirring condition of 650 r / min to obtain the deashing and bleaching agent.

[0057] Example 5

[0058] The formula 5 of the deashing bleaching agent is as follows: in terms of weight percentage, phytic acid 2%, hydrogen peroxide 10%, modified ion neutralizer 10%, citric acid 2%, and the balance is deionized water.

[0059] The preparation process of the modified ion neutralizer is consistent with that of Example 1.

[0060] A method for preparing a weakly acidic aluminum alloy deashing and bleaching agent, the preparation method of the deashing and bleaching agent comprising the following steps: according to formula 5, inositol hexaphosphate, hydrogen peroxide, a modified ion neutralizer, and citric acid are sequentially added into deionized water at room temperature, and mixed for 30 minutes under a stirring condition of 650 r / min to obtain the deashing and bleaching agent.

[0061] Comparative Example 1

[0062] A conventional strong acid deashing bleaching agent is used as a control. The formula of the conventional strong acid deashing bleaching agent is as follows: by weight percentage, 95% concentrated nitric acid and 5% hydrofluoric acid, wherein the mass fraction of concentrated nitric acid is 75% and the mass fraction of hydrofluoric acid is 50%.

[0063] A method for preparing a conventional strong acidic deashing bleaching agent comprises the following steps: according to a formula, concentrated nitric acid and hydrofluoric acid are mixed at room temperature for 30 minutes to obtain the conventional strong acidic deashing bleaching agent.

[0064] Comparative Example 2

[0065] During the preparation of the modified ion neutralizer, green tea powder was not added, and the remaining steps were consistent with those in Example 1.

[0066] Comparative Example 3

[0067] During the preparation of the modified ion neutralizer, sodium dodecyl sulfate was not added, and the remaining steps were consistent with those in Example 1.

[0068] Comparative Example 4

[0069] During the preparation of the modified ion neutralizer, Triton X-100 was not added, and the remaining steps were consistent with those in Example 1.

[0070] Comparative Example 5

[0071] No ethylene glycol was added during the preparation of the modified ion neutralizer, and the remaining steps were consistent with Example 1.

[0072] Liming and bleaching test

[0073] The deashing and bleaching agents in the embodiments and comparative examples were tested for their deashing and bleaching effects. The testing method was as follows: 10 groups of aluminum alloy sheets that were blackened by alkali etching from the same batch of production were taken as test objects, each group containing 50 aluminum alloy sheets. The 10 groups of aluminum alloy sheets were treated with deashing and bleaching agents prepared in the embodiments and comparative examples, respectively. After the deashing and bleaching treatment, the surface bleaching color abnormality and uniformity of the aluminum alloy sheets were inspected under a desk lamp. If there was no abnormal bleaching color on the surface of the aluminum alloy sheet and the entire surface was uniform, it was qualified. Otherwise, it was unqualified. The specific test results are shown in the table below.

[0074]

[0075] The data of the examples and comparative examples show that the performance of the prepared weak acid deashing bleaching agent is better than that of the traditional strong acid deashing bleaching agent, and the deashing bleaching effect is better as the proportion of raw materials other than deionized water in the components increases. In addition, the weak acid deashing bleaching agent prepared by using green tea powder, sodium dodecyl sulfate, Triton X-100 and ethylene glycol to modify the ion neutralizer has better performance.

[0076] Stability test of weak acid ash removal bleaching agent working solution

[0077] The stability performance test of the embodiment was carried out, and the test method was as follows: 10 groups of aluminum alloy sheets from the same batch of production that were blackened by alkaline etching were taken as test objects, each group containing 50 aluminum alloy sheets, and the 10 groups of aluminum alloy sheets were respectively placed in the embodiment and the comparative example for deashing and bleaching. The working liquid of each group of the embodiment was 2L of deashing and bleaching agent stock solution. When the deashing and bleaching were completed, the temperature of the working liquid was tested. When the temperature was higher than 50°C, it was considered that the working liquid was about to fail. The lower the temperature, the more stable the embodiment was, the better the effectiveness was, and the larger the aluminum alloy treatment area could be deashed and bleached with the same volume of working liquid. The specific test results are shown in the table below.

[0078] Test Group Aluminum alloy sheet total Working fluid volume (L) Working fluid temperature (℃) Example 1 50 2 30 Example 2 50 2 32 Example 3 50 2 37 Example 4 50 2 37 Example 5 50 2 45 Comparative Example 1 50 2 49 Comparative Example 2 50 2 33 Comparative Example 3 50 2 35 Comparative Example 4 50 2 36 Comparative Example 5 50 2 38

[0079] Comparative Examples show that when the deionized water content is high and the proportion of stabilizer, modified ion neutralizer and complexing agent is low, the temperature of the weak acid deashing bleaching agent rises fastest during operation and the timeliness of the working solution is the worst; when the deionized water content is low, the temperature rise rate of the working solution is normal and the timeliness of the working solution is good. Comparative Examples and Comparative Examples show that the weak acid deashing bleaching agent prepared by using green tea powder, sodium dodecyl sulfate, Triton X-100 and ethylene glycol to modify the ion neutralizer has better stability.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A weakly acidic aluminum alloy deashing and bleaching agent, characterized in that: The formula of the deashing bleaching agent is as follows: by weight percentage, 2-5% stabilizer, 10-50% oxidant, 10-15% modified ion neutralizer, 2-5% complexing agent, and the balance deionized water. Wherein, the preparation method of the modified ion neutralizer is as follows: S1: ammonium bifluoride and hydrofluoric acid are mixed and dissolved in deionized water, and ultrasonically stirred for 30 minutes to obtain a solution A with a mass fraction of 50%; S2: Mix green tea powder and deionized water in a mass ratio of 1:50, heat and stir at 70°C for 4 h, centrifuge at 4000-5000 rpm / min for 10 min, remove the precipitate and obtain solution B; S3: Solution A and solution B are mixed in a volume ratio of (7-9):1, and stirred at a speed of 500-600 rpm / min for 1 h. Sodium dodecyl sulfate and Triton X-100 are mixed and added to the mixed solution of solution A and solution B, and stirring is continued for 30 min to obtain solution C; S4: adding ethylene glycol in an amount of 5 wt % to solution C, ultrasonicating for 30 min, washing with deionized water and drying in a constant temperature drying oven at 60° C. for 12 h to obtain the modified ion neutralizer.

2. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: The stabilizer is one or two of phytic acid and polyethylene polyamine polyalkylene phosphonate.

3. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: The oxidant is one or more of hydrogen peroxide, sodium chlorate and sodium hypochlorite.

4. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: The complexing agent is one or two of citric acid and ethylenediaminetetraacetic acid.

5. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: In the S1, ammonium bifluoride and hydrofluoric acid are mixed in a mass ratio of 3:

1.

6. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: In the S3, sodium dodecyl sulfate and Triton X-100 are mixed in a mass ratio of 1:

1.

7. A weakly acidic aluminum alloy deashing and bleaching agent according to claim 1, characterized in that: The ultrasonic power in S4 is 5-7 kHz.

8. A method for preparing the weakly acidic aluminum alloy deashing and bleaching agent according to any one of claims 1 to 7, characterized in that: The preparation method of the deashing bleaching agent comprises the following steps: adding a stabilizer, an oxidant, a modified ion neutralizer and a complexing agent to deionized water in sequence at room temperature according to the formula ratio, and mixing them for 30 minutes under stirring conditions to obtain the deashing bleaching agent.

9. The method for preparing a weakly acidic aluminum alloy deashing and bleaching agent according to claim 8, characterized in that: The stirring speed in the preparation process of the deashing bleaching agent is 650-750 r / min.

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