Efficient decontamination acidic metal cleaning agent

Abstract

The invention relates to the technical field of metal cleaning aids, and discloses an efficient decontamination acidic metal cleaning agent which comprises the following components in percentage by weight: 12-28% of non-oxidizing acid, 1.5-6% of a corrosion inhibitor, 4-12% of a surfactant, 0.8-3% of a complexing agent, 1.5-5% of a solubilizer, 2-8% of an organic solvent, 3-10% of a pH regulator, 0.1-0.6% of a defoaming agent, 0.2-1.2% of an antirust agent and the balance of deionized water. Through synergistic compounding of organic acid and inorganic acid and combination of a ternary corrosion inhibition system of benzotriazole, mercaptobenzothiazole and imidazoline derivatives, the decontamination efficiency and metal compatibility are remarkably improved, the synergistic effect of citric acid and sulfuric acid enables the corrosion rate of carbon steel to be reduced, meanwhile, the rust-proof time of a copper sheet is prolonged to 72 hours or above, and the rust-proof effect of the copper sheet is improved. The effect is derived from complementation of chelation of organic acid and strong solubility of inorganic acid and directional protection of the corrosion inhibition component on the multi-metal surface.

Description

Technical Field

[0001] The invention relates to the technical field of metal cleaning additives, in particular to an acidic metal cleaning agent with high-efficiency decontamination. Background Art

[0002] During the processing, storage and transportation of metal surfaces, they are often contaminated with various dirt, such as oil, rust, oxide scale, dust, etc. These dirt not only affect the appearance of the metal, but also have a very adverse effect on the subsequent processing technology, product quality and the service life of the equipment. In the field of metal processing, manufacturing and maintenance, the cleaning of metal surfaces is a vital link. With the continuous development of industry and the increasing sophistication of technology, the requirements for metal cleaning agents are also becoming increasingly stringent.

[0003] Traditional acidic metal cleaners for high-efficiency decontamination primarily use strong inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid as their primary ingredients. While these cleaners possess a certain level of decontamination capability, they also suffer from numerous drawbacks that should not be ignored. Strong acidic cleaners are extremely corrosive to metal substrates, easily causing problems such as excessive corrosion and hydrogen embrittlement on the metal surface. This is particularly true when cleaning non-ferrous metals such as aluminum, copper, and their alloys, which can severely damage the metal surface, affecting its mechanical properties and service life. Traditional acidic cleaners also have poor decontamination selectivity, and while removing oil and rust, they can also damage beneficial components on the metal substrate surface, leading to a decrease in metal surface performance. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides an acidic metal cleaning agent with high decontamination efficiency, which solves the problem that traditional acidic cleaning agents have poor decontamination selectivity and easily destroy the beneficial components on the surface of the metal substrate while removing oil and rust, resulting in a decrease in metal surface performance.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] A highly effective decontamination acidic metal cleaning agent comprising the following components by weight percentage:

[0007] Non-oxidizing acid 12-28%, corrosion inhibitor 1.5-6%, surfactant 4-12%, complexing agent 0.8-3%, solubilizer 1.5-5%, organic solvent 2-8%, pH adjuster 3-10%, defoamer 0.1-0.6%, rust inhibitor 0.2-1.2%, the balance is deionized water;

[0008] By adopting the above technical solution: the highly efficient decontamination acidic metal cleaning agent is produced through the synergistic compounding of organic acid and inorganic acid, combined with a ternary corrosion inhibition system of benzotriazole, mercaptobenzothiazole and imidazoline derivatives, which significantly improves the decontamination efficiency and metal compatibility. The synergistic effect of citric acid and sulfuric acid reduces the corrosion rate of carbon steel to 0.021mm / a, and at the same time extends the rust prevention time of copper sheets to more than 72 hours, which is 3 times longer than that of traditional hydrochloric acid-based cleaning agents. This effect is due to the complementary chelating effect of organic acid and the strong solubility of inorganic acid, as well as the directional protection of multi-metal surfaces by the corrosion inhibition components.

[0009] The non-oxidizing acid is a mixture of an organic acid and an inorganic acid, wherein the organic acid accounts for 45-65% of the total mass of the non-oxidizing acid. The pH regulator controls the pH value of the system at 1.8-3.2.

[0010] Preferably, the organic acid is a combination of at least two of citric acid, tartaric acid, and aminosulfonic acid, with a mass ratio of 4:1 to 3:2; the inorganic acid is a combination of phosphoric acid and sulfuric acid, with a mass ratio of 1:1 to 1:2, and the phosphoric acid concentration is ≥85wt%, and the sulfuric acid concentration is ≥98wt%.

[0011] Preferably, the corrosion inhibitor comprises a ternary composite system of benzotriazole, mercaptobenzothiazole and imidazoline derivatives, wherein benzotriazole accounts for 40-60% of the total mass of the corrosion inhibitor, mercaptobenzothiazole accounts for 20-35%, and imidazoline derivatives account for 15-30%, and the amine value of the imidazoline derivatives is 150-220 mgKOH / g.

[0012] Preferably, the surfactant is a compound of anionic sodium dodecylbenzene sulfonate, nonionic fatty alcohol polyoxyethylene ether and amphoteric surfactant cocamidopropyl betaine, the mass ratio of the three being 3-4:2-3:1, wherein the ethylene oxide addition number of the fatty alcohol polyoxyethylene ether is 5-9.

[0013] Preferably, the complexing agent is a combination of disodium EDTA and sodium gluconate in a mass ratio of 1.2:1 to 1:1; the organic solvent is a mixture of ethanol and ethylene glycol in a volume ratio of 2:1 to 1:1, and the purity of ethylene glycol is ≥99.5% and the moisture content is ≤0.1%.

[0014] Preferably, the rust inhibitor is a complex of sodium molybdate, tannic acid and hydroxyimidazoline, the mass ratio of the three is 5-7:1-2:0.5-1, and the total addition amount is 0.3-1.0%, wherein the tannin content of tannic acid is ≥90%.

[0015] Preferably, the pH adjuster is a mixed acid of phosphoric acid and concentrated sulfuric acid, with a volume ratio of 1:2 to 1:3. After addition, the pH value of the system is 2.0-3.0, and the addition rate of the mixed acid is 0.5-1.2 mL / min. During addition, the system temperature is maintained at 25-35°C.

[0016] Preferably, a method for preparing an acidic metal cleaning agent with high efficiency in decontamination, for use in an acidic metal cleaning agent with high efficiency in decontamination, comprises the following steps:

[0017] S1. Heat deionized water to 35-50°C, add organic acid and inorganic acid, and stir to dissolve at a speed of 400-700 rpm for 15-25 minutes;

[0018] S2. Add the complexing agent and solubilizer in sequence, maintain the temperature at 45-55°C, and stir until completely dissolved;

[0019] S3. Add surfactants in two stages: first add anionic and nonionic surfactants, heat to 60-70°C and disperse at 800-1000 rpm for 10-20 minutes, then add amphoteric surfactants, cool to 40-50°C and stir at 500-700 rpm for 10-15 minutes;

[0020] S4. Add corrosion inhibitor and rust inhibitor, control the temperature at 30-40°C, stirring speed at 300-450 rpm, and stirring time for 40-60 min;

[0021] S5. Add defoamer in two batches: the first batch is 60-80% of the total amount at the beginning of S4, and the remaining portion is added 5-10 minutes before the end of S4;

[0022] S6. Finally, add the organic solvent and the remaining water, stir at 200-300 rpm for 20-30 min, filter, and allow to stand for 18-36 h.

[0023] Preferably, the high-speed shear dispersion in S3 is carried out in three stages: the first stage is dispersion at 800-900 rpm for 5-8 min, the second stage is dispersion at 1000-1200 rpm for 8-12 min, and the third stage is cooling and stirring at 600-800 rpm for 5-10 min, and the temperature fluctuation in each stage does not exceed ±2°C.

[0024] Preferably, an application of an efficient decontamination acidic metal cleaning agent is used for the said efficient decontamination acidic metal cleaning agent, which is suitable for cleaning oil, rust and oxide scale on the surface of steel, copper and aluminum alloy. The cleaning temperature is 45-65°C, the processing time is 5-25min, and the pH value stability is maintained after the cleaning liquid is recycled ≥5 times, the fluctuation is ≤±0.3, and the thickness of the passivation film on the metal surface after cleaning is ≤50nm.

[0025] The present invention provides an acidic metal cleaning agent with high efficiency in decontamination. It has the following beneficial effects:

[0026] 1. The highly efficient acidic metal cleaning agent of the present invention significantly improves cleaning efficiency and metal compatibility through the synergistic compounding of organic and inorganic acids, combined with a ternary corrosion inhibition system of benzotriazole, mercaptobenzothiazole, and imidazoline derivatives. The synergistic effect of citric acid and sulfuric acid reduces the corrosion rate of carbon steel to 0.021 mm / a, while extending the rust prevention time of copper sheets to more than 72 hours, which is three times longer than that of traditional hydrochloric acid-based cleaning agents. This effect is due to the complementary chelation effect of organic acids and the strong solubility of inorganic acids, as well as the directional protection of multi-metal surfaces by the corrosion inhibition components.

[0027] 2. The present invention solves the problems of uneven dispersion and high-temperature decomposition of surfactants by combining a staged gradient shear process with precise temperature control. The three-stage shear process improves the dispersion uniformity of surfactants by 35%. Combined with phosphoric acid gradient penetration, the stainless steel oxide scale removal rate reaches 99.5%, and the cleaning liquid can be recycled up to 7 times. The process parameters are optimized to ensure component stability, and the pH value fluctuation is ≤0.3, meeting the needs of long-term industrial use.

[0028] 3. The present invention achieves low-foaming, high-efficiency cleaning and long-term metal protection through the synergistic application of a sodium molybdate-tannic acid-hydroxyimidazoline composite rust inhibitor and a staged defoaming process. In Example 3, the dynamic foam height was reduced to 15 mm, the passivation film thickness was only 43 nm, and the copper alloy weight loss rate was as low as 0.008 mg / cm². This effect relies on the rust inhibitor's ability to form a dense passivation film and the staged addition strategy of the defoamer, which prevents foam from interfering with the cleaning process and prolongs the metal rust protection period. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a flow chart of a method for preparing an acidic metal cleaning agent with high efficiency in decontamination. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Please see the attached Figure 1 The embodiment of the present invention provides an acidic metal cleaning agent for high-efficiency decontamination, which comprises the following components by weight percentage:

[0032] Non-oxidizing acid 12-28%, corrosion inhibitor 1.5-6%, surfactant 4-12%, complexing agent 0.8-3%, solubilizer 1.5-5%, organic solvent 2-8%, pH adjuster 3-10%, defoamer 0.1-0.6%, rust inhibitor 0.2-1.2%, the balance is deionized water;

[0033] The non-oxidizing acid is a mixture of organic acid and inorganic acid, wherein the organic acid accounts for 45-65% of the total mass of the non-oxidizing acid. The pH regulator controls the pH value of the system at 1.8-3.2.

[0034] Specifically, organic acids can react with oxides, rust and oil stains on the metal surface by virtue of their chelating properties, and stably peel them off; inorganic acids can quickly react with oil stains and carbonate dirt by virtue of their acidity and redox ability to undergo acid-base neutralization and dissolution reactions, thereby improving the cleaning ability of the cleaning agent and accelerating the cleaning speed, achieving the effect of efficiently removing stubborn stains; controlling the pH value in the acidic range of 1.8-3.2 can not only ensure that the cleaning agent has sufficient cleaning power, but also reduce the risk of corrosion to the metal substrate.

[0035] Please see the attached Figure 1 The organic acid is a combination of at least two of citric acid, tartaric acid, and aminosulfonic acid, with a mass ratio of 4:1 to 3:2; the inorganic acid is a combination of phosphoric acid and sulfuric acid, with a mass ratio of 1:1 to 1:2, and the phosphoric acid concentration is ≥85wt%, and the sulfuric acid concentration is ≥98wt%.

[0036] Specifically, the organic acid compound has a synergistic effect, which can enhance the chelating ability and decontamination effect on oxides and rust on the metal surface. Among them, at least two of citric acid, tartaric acid, and aminosulfonic acid are compounded in a mass ratio of 4:1 to 3:2, which ensures the chelating effect while reducing costs. The raw materials are easily available and the ratio is reasonable, which is conducive to industrial application. The inorganic acid is a combination of phosphoric acid and sulfuric acid in a mass ratio of 1:1 to 1:2, with a phosphoric acid concentration of ≥85wt% and a sulfuric acid concentration of ≥98wt%. The high concentration of phosphoric acid provides strong acidity to destroy the rust structure on the metal surface, and sulfuric acid enhances the ability to remove oil and carbonate dirt. The two work together to enhance the decontamination, rust removal, and oil cleaning effects of the cleaning agent. The mass ratio is controlled within a reasonable range to ensure the acid strength and stability, avoid excessive sulfuric acid causing aggravated corrosion, and enable the cleaning agent to effectively remove stubborn dirt while reducing potential damage to the metal substrate.

[0037] Please see the attached Figure 1 The corrosion inhibitor comprises a ternary composite system of benzotriazole, mercaptobenzothiazole and imidazoline derivatives, wherein benzotriazole accounts for 40-60% of the total mass of the corrosion inhibitor, mercaptobenzothiazole accounts for 20-35%, and imidazoline derivatives account for 15-30%, and the amine value of the imidazoline derivatives is 150-220 mgKOH / g.

[0038] Specifically, benzotriazole can preferentially adsorb on the active sites on the metal surface to form a protective film, thereby effectively preventing direct contact between acidic substances and the metal and reducing the probability of corrosion reactions; mercaptobenzothiazole, with the strong adsorption properties of its sulfur atoms, further enhances the density and stability of the protective film, making the protective film more evenly covered on the metal surface, and providing a uniform protective effect even on complex metal surfaces; and imidazoline derivatives, due to their suitable amine value, can chemically react with the metal surface in an acidic environment to form a strong complex film. This film can not only block the erosion of acidic substances, but also repair tiny defects caused by local corrosion, thereby improving the overall protective ability of the protective film.

[0039] Please see the attached Figure 1 The surfactant is a compound of anionic sodium dodecylbenzene sulfonate, nonionic fatty alcohol polyoxyethylene ether and amphoteric surfactant cocamidopropyl betaine, with a mass ratio of 3-4:2-3:1. The ethylene oxide addition number of the fatty alcohol polyoxyethylene ether is 5-9.

[0040] Specifically, sodium dodecylbenzene sulfonate has good detergency and penetrating properties, and can quickly emulsify and disperse loose attachments such as oil and dust on the metal surface, so that the dirt is separated from the metal surface, laying a good foundation for the subsequent cleaning process; fatty alcohol polyoxyethylene ether (ethylene oxide addition number is 5-9) relies on its non-ionic properties to enhance the cleaning agent's ability to wrap and dissolve oil stains, especially for some oil stain components with a certain polarity, it can effectively disperse them in the water phase to prevent the oil stains from re-accumulating on the metal surface. At the same time, it can also reduce the cleaning agent's Surface tension improves the spreading performance of the cleaning agent on the metal surface, allowing the cleaning agent to cover the metal surface more evenly and enhance the cleaning effect; and cocamidopropyl betaine, as an amphoteric surfactant, can exert its unique properties in an acidic environment. It can not only further improve the cleaning ability of the cleaning agent, but also form a protective film on the metal surface, reducing the corrosion of the acidic components to the metal during the cleaning process. At the same time, it gives the cleaning agent a certain degree of flexibility and antistatic properties, making the metal surface brighter and smoother after cleaning, thereby improving the quality and performance of the metal surface.

[0041] Please see the attached Figure 1 The complexing agent is a combination of disodium EDTA and sodium gluconate in a mass ratio of 1.2:1 to 1:1; the organic solvent is a mixture of ethanol and ethylene glycol in a volume ratio of 2:1 to 1:1, and the purity of ethylene glycol is ≥99.5%, and the moisture content is ≤0.1%.

[0042] Specifically, disodium EDTA can effectively chelate heavy metal ions on the metal surface, preventing these ions from reacting adversely with other ingredients in the cleaning agent, and at the same time avoiding the redeposition of metal ions on the metal surface during the cleaning process to form stains or spots; sodium gluconate has good biodegradability and corrosion inhibition properties, and performs well in chelating hardness ions such as calcium and magnesium, which are usually related to rust and scale on the metal surface; the two are matched in an appropriate proportion to achieve efficient complexation of multiple metal ions, enhance the adaptability and removal ability of the cleaning agent to various dirt, while reducing the impact on the environment and improving the environmental performance of the cleaning agent; among them, ethanol has good volatility and solubility, and can quickly dissolve and disperse organic dirt such as grease and resin on the metal surface, so that the dirt is separated from the metal surface. At the same time, it can evaporate quickly after cleaning and will not leave residue on the metal surface, ensuring the cleanliness of the metal surface; ethylene glycol has a higher boiling point and viscosity, which can reduce the volatilization rate of the cleaning agent during the cleaning process, prolong the contact time between the cleaning agent and the metal surface, and enhance the cleaning effect.

[0043] Please see the attached Figure 1 The rust inhibitor is a complex of sodium molybdate, tannic acid and hydroxyimidazoline, the mass ratio of the three is 5-7:1-2:0.5-1, and the total addition amount is 0.3-1.0%, of which the tannin content of tannic acid is ≥90%.

[0044] Specifically, sodium molybdate forms a passivation film on the metal surface, blocking corrosive media; tannic acid adsorbs on the metal surface, forming a protective complex with metal ions to enhance protection; and hydroxyimidazoline adsorbs to form a film, filling minor surface imperfections. These three factors work together to provide long-lasting rust protection.

[0045] Please see the attached Figure 1 The pH regulator is a mixed acid of phosphoric acid and concentrated sulfuric acid, with a volume ratio of 1:2 to 1:3. After addition, the pH value of the system is 2.0-3.0, and the addition rate of the mixed acid is 0.5-1.2 mL / min. The system temperature is maintained at 25-35°C during addition.

[0046] Specifically, by using a mixed acid of phosphoric acid and concentrated sulfuric acid as a pH adjuster with a volume ratio of 1:2 to 1:3, the acidic environment of the cleaning agent can be precisely controlled. During the addition process, the mixed acid is slowly added at a rate of 0.5-1.2 mL / min and the system temperature is maintained at 25-35°C to ensure that the pH value is stable within the range of 2.0-3.0. Such acidic conditions not only help improve the cleaning agent's ability to remove oil and rust from metal surfaces, but also inhibit excessive corrosion, thereby extending the service life of metal parts. At the same time, this precise pH adjustment is crucial to optimizing the overall performance of the cleaning agent, ensuring the reliability and safety of the cleaning agent in different application scenarios.

[0047] Please see the attached Figure 1 A method for preparing an acidic metal cleaning agent with high efficiency in decontamination, comprising the following steps:

[0048] S1. Heat deionized water to 35-50°C, add organic acid and inorganic acid, and stir to dissolve at a speed of 400-700 rpm for 15-25 minutes;

[0049] S2. Add the complexing agent and solubilizer in sequence, maintain the temperature at 45-55°C, and stir until completely dissolved;

[0050] S3. Add surfactants in two stages: first add anionic and nonionic surfactants, heat to 60-70°C and disperse at 800-1000 rpm for 10-20 minutes, then add amphoteric surfactants, cool to 40-50°C and stir at 500-700 rpm for 10-15 minutes;

[0051] S4. Add corrosion inhibitor and rust inhibitor, control the temperature at 30-40°C, stirring speed at 300-450 rpm, and stirring time for 40-60 min;

[0052] S5. Add defoamer in two batches: the first batch is 60-80% of the total amount at the beginning of S4, and the remaining portion is added 5-10 minutes before the end of S4;

[0053] S6. Finally, add the organic solvent and the remaining water, stir at 200-300 rpm for 20-30 min, filter, and allow to stand for 18-36 h.

[0054] Please see the attached Figure 1 In S3, high-speed shear dispersion is carried out in three stages: the first stage is dispersed at 800-900 rpm for 5-8 minutes, the second stage is dispersed at 1000-1200 rpm for 8-12 minutes, and the third stage is cooled and stirred at 600-800 rpm for 5-10 minutes, and the temperature fluctuation in each stage does not exceed ±2°C.

[0055] Specifically, the first stage is to disperse the surfactant at 800-900 rpm for 5-8 minutes to evenly disperse the surfactant and form a preliminary emulsion structure. The second stage is to disperse the surfactant at 1000-1200 rpm for 8-12 minutes to refine the surfactant particles and enhance their ability to encapsulate oil stains. The third stage is to cool and stir at 600-800 rpm for 5-10 minutes to maintain the structure while cooling. Temperature fluctuations at each stage are controlled within ±2°C to prevent excessive temperatures from causing surfactant ineffectiveness or excessive low temperatures from affecting dispersion, thereby improving the detergent's cleaning ability and stability.

[0056] Please see the attached Figure 1, an application of an efficient decontamination acidic metal cleaning agent, used for the above-mentioned efficient decontamination acidic metal cleaning agent, suitable for cleaning oil, rust and oxide scale on the surface of steel, copper and aluminum alloy. The cleaning temperature is 45-65℃, the processing time is 5-25min, and the pH value remains stable after the cleaning liquid is recycled ≥5 times, with fluctuation ≤±0.3, and the thickness of the passivation film on the metal surface after cleaning is ≤50nm.

[0057] Specifically, the thickness of the passivation film formed on the metal surface after cleaning is ≤50nm, which can effectively protect the metal from further corrosion, improve the corrosion resistance and service life of the metal products, and ensure their subsequent processing and use performance.

[0058] Example 1:

[0059] (1) Technical solution

[0060] 1. Components and ratio (wt%)

[0061] Non-oxidizing acid: 18% (of which citric acid accounts for 75% of the total mass of organic acid, sulfamic acid accounts for 25%; the mass ratio of phosphoric acid to sulfuric acid is 1:1).

[0062] Corrosion inhibitor: 3.5% (based on the total mass of corrosion inhibitor: benzotriazole 50%, mercaptobenzothiazole 30%, hydroxyimidazoline 20%, amine value 180mgKOH / g).

[0063] Surfactant: 8% (sodium dodecylbenzenesulfonate 4.8%, fatty alcohol polyoxyethylene ether (EO=7) 3.2%, cocamidopropyl betaine 0.8%).

[0064] Complexing agent: 2% (disodium EDTA: sodium gluconate = 1.2:1).

[0065] Solubilizer: 3% (sodium xylene sulfonate).

[0066] Organic solvent: 5% (ethanol: ethylene glycol = 2:1, ethylene glycol purity 99.6%).

[0067] pH adjuster: 6% (phosphoric acid: concentrated sulfuric acid = 1:2, addition rate 0.8 mL / min, temperature 30°C).

[0068] Defoaming agent: 0.3%.

[0069] Rust inhibitor: 0.7% (sodium molybdate: tannic acid: hydroxyimidazoline = 6:1.5:0.8, tannic acid tannin content 92%).

[0070] Balance deionized water: 53.5%.

[0071] 2. Preparation process

[0072] Heat deionized water to 40°C (temperature control accuracy ±1°C), add citric acid, aminosulfonic acid, phosphoric acid and sulfuric acid, and stir at 500 rpm for 20 minutes (the order of acid addition: add organic acid first and then inorganic acid).

[0073] Add the complexing agent and solubilizer in sequence, maintain stirring at 45°C until dissolved.

[0074] The surfactant was added in two stages: sodium dodecylbenzene sulfonate and fatty alcohol polyoxyethylene ether were added first, the temperature was raised to 65°C and sheared and dispersed at 900 rpm for 15 minutes; after cooling to 45°C, cocamidopropyl betaine was added and stirred at 600 rpm for 12 minutes.

[0075] Add corrosion inhibitor and rust inhibitor, control at 35°C, and stir at 350 rpm for 50 min.

[0076] Defoamer (polyether-modified silicone, 0.21% for the first addition and 0.09% for the second addition) was added twice.

[0077] Finally, the organic solvent and the remaining amount of water were added, stirred at 250 rpm for 25 min, filtered and aged for 24 h.

[0078] 2. Comparative Experimental Design

[0079] Test standards: Decontamination rate (GB / T1771-2007), corrosion rate (GB / T10125-2012), and rust resistance (GB / T6144-2010).

[0080] Control group: commercially available acidic cleaning agent (main components are 10% hydrochloric acid + 5% dodecylbenzenesulfonic acid).

[0081] (3) Implementation effect verification

[0082] Test items Example 1 control group Decontamination rate (40℃, 15min) 98.2% 89.5% Carbon steel corrosion rate (mm / a) 0.021 0.153 Copper sheet rust prevention time (h) >72 24

[0083] (IV) Summary

[0084] In Example 1, through the synergistic effect of citric acid (chelating Fe³⁺) and sulfuric acid (dissolving FeO), combined with the complementary effects of benzotriazole (Cu protection) and hydroxyimidazoline (broad-spectrum corrosion inhibition), the corrosion rate of carbon steel was reduced by 86.3% compared with the control group (calculated and corrected from the original data), verifying the directional matching mechanism of the acid system and the corrosion inhibitor.

[0085] Example 2

[0086] (1) Technical solution

[0087] 1. Components and ratio (wt%)

[0088] Non-oxidizing acid: 22% (tartaric acid accounts for 66.7% of the total mass of organic acids, sulfamic acid accounts for 33.3%; the mass ratio of phosphoric acid to sulfuric acid is 1:1.5).

[0089] Corrosion inhibitor: 4.5% (benzotriazole 55%, mercaptobenzothiazole 25%, mercaptoimidazoline 20%, amine value 200mgKOH / g).

[0090] Surfactant: 10% (5.6% sodium dodecylbenzenesulfonate, 3.8% fatty alcohol polyoxyethylene ether (EO=5), 0.6% cocamidopropyl betaine).

[0091] Complexing agent: 1.8% (disodium EDTA: sodium gluconate = 1:1).

[0092] Solubilizer: 4.5% (urea).

[0093] Organic solvent: 6% (ethanol:ethylene glycol = 1:1).

[0094] pH adjuster: 8% (phosphoric acid: concentrated sulfuric acid = 1:3, addition rate 1.0 mL / min, temperature 28°C).

[0095] Defoaming agent: 0.4%.

[0096] Rust inhibitor: 0.9% (sodium molybdate: tannic acid: hydroxyimidazoline = 7:2:1).

[0097] Balance deionized water: 41.9%.

[0098] 2. Process optimization

[0099] Step 3 uses three-stage shearing:

[0100] The first stage (800 rpm / 6 min): dispersion of anionic surfactant;

[0101] The second stage (1100 rpm / 10 min): activation of nonionic surfactant;

[0102] The third stage (700rpm / 8min): stabilizing the amphoteric surfactant;

[0103] The temperature is controlled by a PID closed-loop system with a fluctuation of ≤±1.5℃.

[0104] 2. Comparative Experimental Design

[0105] Test standards: oxide scale removal rate (HB5227-2008), aluminum alloy pitting density (ASTMG46-94).

[0106] Control group: Patent CN107384543A (sulfamic acid + thiourea system).

[0107] (3) Implementation effect verification

[0108] Test items Example 2 control group Stainless steel oxide scale removal rate (60℃, 20min) 99.5% 93.2% Aluminum alloy pitting density (pieces / cm²) 2.1 15.6 Number of times the cleaning solution is recycled (pH fluctuation ≤ 0.3) 7 times 3 times

[0109] (IV) Summary

[0110] In Example 2, the number of cycles was increased by 133% by gradient infiltration of the oxide scale with phosphoric acid (XRD verified that the Fe3O4 removal rate was >99%) and combined with a three-stage shear process (SEM showed that the surfactant dispersion uniformity was improved by 35%), meeting the requirements of long-term industrial use.

[0111] Example 3

[0112] (1) Technical solution

[0113] 1. Components and ratio (wt%)

[0114] Non-oxidizing acid: 25% (citric acid: tartaric acid = 4:1; phosphoric acid: sulfuric acid = 1:2).

[0115] Corrosion inhibitor: 5.5% (benzotriazole 60%, mercaptobenzothiazole 30%, mercaptoimidazoline 10%, amine value 150mgKOH / g).

[0116] Surfactant: 12% (sodium dodecylbenzenesulfonate: fatty alcohol polyoxyethylene ether (EO=9): cocamidopropyl betaine = 3:3:1).

[0117] Complexing agent: 2.5% (disodium EDTA: sodium gluconate = 1.2:1).

[0118] Solubilizer: 5% (sodium xylene sulfonate).

[0119] Organic solvent: 8% (ethanol:ethylene glycol = 2:1).

[0120] pH adjuster: 10% (phosphoric acid: concentrated sulfuric acid = 1:2.5, addition rate 1.2 mL / min, temperature 25°C).

[0121] Defoaming agent: 0.6%.

[0122] Rust inhibitor: 1.1% (sodium molybdate 0.73%, tannic acid 0.24%, hydroxyimidazoline 0.13%).

[0123] Balance deionized water: 30.3%.

[0124] 2. Process optimization

[0125] Step 5: Add the defoamer in three steps:

[0126] S4 initial addition 60% (0.36%);

[0127] 20% (0.12%) was added during the middle stage (20 min after the start of S4);

[0128] Add 20% (0.12%) 5 minutes before the end;

[0129] The defoamer type is a mineral oil-polyether composite system (HLB value 8-10).

[0130] 2. Comparative Experimental Design

[0131] Test standards: passivation film thickness (GB / T9792-2003), foam height (ISO696-1975).

[0132] Control group: commercially available low-foaming acidic cleaning agent (containing silicone defoaming agent).

[0133] (3) Implementation effect verification

[0134] Test items Example 3 control group Passivation film thickness (nm) 43±5 82±10 Dynamic foam height (50℃, 5min) 15mm 45mm Copper alloy weight loss rate (mg / cm²) 0.008 0.035

[0135] (IV) Summary

[0136] In Example 3, by optimizing the defoaming agent addition strategy, the dynamic foam height was reduced by 66.7%, the copper alloy protection performance was improved by 76.8%, and the passivation film thickness was only 52.4% of that of the control group, indicating the key role of the staged process in functional synergy.

[0137] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An acidic metal cleaning agent with high efficiency decontamination, characterized in that: The following components are included by weight percentage: Non-oxidizing acid 12-28%, corrosion inhibitor 1.5-6%, surfactant 4-12%, complexing agent 0.8-3%, solubilizer 1.5-5%, organic solvent 2-8%, pH adjuster 3-10%, defoamer 0.1-0.6%, rust inhibitor 0.2-1.2%, the balance is deionized water; The non-oxidizing acid is a mixture of an organic acid and an inorganic acid, wherein the organic acid accounts for 45-65% of the total mass of the non-oxidizing acid. The pH regulator controls the pH value of the system at 1.8-3.

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2. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The organic acid is a combination of at least two of citric acid, tartaric acid, and aminosulfonic acid, with a mass ratio of 4:1 to 3:2; the inorganic acid is a combination of phosphoric acid and sulfuric acid, with a mass ratio of 1:1 to 1:2, and the phosphoric acid concentration is ≥85wt%, and the sulfuric acid concentration is ≥98wt%.

3. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The corrosion inhibitor comprises a ternary composite system of benzotriazole, mercaptobenzothiazole and imidazoline derivatives, wherein benzotriazole accounts for 40-60% of the total mass of the corrosion inhibitor, mercaptobenzothiazole accounts for 20-35%, and imidazoline derivatives account for 15-30%, and the amine value of the imidazoline derivatives is 150-220 mgKOH / g.

4. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The surfactant is a compound of anionic sodium dodecylbenzene sulfonate, nonionic fatty alcohol polyoxyethylene ether and amphoteric surfactant cocamidopropyl betaine, the mass ratio of the three being 3-4:2-3:1, wherein the ethylene oxide addition number of the fatty alcohol polyoxyethylene ether is 5-9.

5. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The complexing agent is a combination of disodium EDTA and sodium gluconate, with a mass ratio of 1.2:1 to 1:1; the organic solvent is a mixture of ethanol and ethylene glycol, with a volume ratio of 2:1 to 1:1, and the purity of the ethylene glycol is ≥99.5% and the moisture content is ≤0.1%.

6. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The rust inhibitor is a complex of sodium molybdate, tannic acid and hydroxyimidazoline, the mass ratio of the three is 5-7:1-2:0.5-1, and the total addition amount is 0.3-1.0%, wherein the tannin content of the tannic acid is ≥90%.

7. The acidic metal cleaning agent for high-efficiency decontamination according to claim 1, characterized in that: The pH adjuster is a mixed acid of phosphoric acid and concentrated sulfuric acid, with a volume ratio of 1:2 to 1:

3. After addition, the pH value of the system is 2.0-3.0, and the addition rate of the mixed acid is 0.5-1.2 mL / min. During addition, the system temperature is maintained at 25-35°C.

8. A method for preparing an acidic metal cleaning agent with high efficiency decontamination, characterized in that: An acidic metal cleaning agent for high-efficiency decontamination according to any one of claims 1 to 7, comprising the following steps: S1. Heat deionized water to 35-50°C, add organic acid and inorganic acid, and stir to dissolve at a speed of 400-700 rpm for 15-25 minutes; S2. Add the complexing agent and solubilizer in sequence, maintain the temperature at 45-55°C, and stir until completely dissolved; S3. Add surfactants in two stages: first add anionic and nonionic surfactants, heat to 60-70°C and disperse at 800-1000 rpm for 10-20 minutes, then add amphoteric surfactants, cool to 40-50°C and stir at 500-700 rpm for 10-15 minutes; S4. Add corrosion inhibitor and rust inhibitor, control the temperature at 30-40°C, stirring speed at 300-450 rpm, and stirring time for 40-60 min; S5. Add defoamer in two batches: the first batch is 60-80% of the total amount at the beginning of S4, and the remaining portion is added 5-10 minutes before the end of S4; S6. Finally, add the organic solvent and the remaining water, stir at 200-300 rpm for 20-30 min, filter, and allow to stand for 18-36 h.

9. The method for preparing a highly efficient decontamination acidic metal cleaning agent according to claim 8, characterized in that: The high-speed shear dispersion in S3 is carried out in three stages: the first stage is dispersion at 800-900 rpm for 5-8 min, the second stage is dispersion at 1000-1200 rpm for 8-12 min, and the third stage is stirring at 600-800 rpm with cooling for 5-10 min, and the temperature fluctuation in each stage does not exceed ±2°C.

10. Application of an acidic metal cleaning agent for high-efficiency decontamination, characterized by: An acidic metal cleaning agent for high-efficiency decontamination as described in any one of claims 1 to 7 is suitable for cleaning oil stains, rust and oxide scale on the surfaces of steel, copper and aluminum alloys. The cleaning temperature is 45-65°C, the treatment time is 5-25 minutes, the pH value remains stable after the cleaning solution is recycled ≥5 times, the fluctuation is ≤±0.3, and the thickness of the passivation film on the metal surface after cleaning is ≤50nm.

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