Thickening paste and preparation method thereof, and viscosity adjusting method of pickling passivation solution

Abstract

The invention provides a thickening paste and a preparation method thereof, and a viscosity adjusting method of a pickling passivation solution. The thickening paste is prepared from the following components in percentage by weight: 20 to 30 percent of stearic acid, 1 to 5 percent of a first emulsifier, 64.5 to 78.8 percent of purified water and 0.2 to 0.5 percent of a second emulsifier; wherein the first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form a water phase. The thickening paste is non-toxic and pollution-free, does not release harmful gas, and is green and environment-friendly. The thickening paste is suitable for adjusting the viscosity of the pickling passivation solution, so that the pickling passivation solution can exist and act in different forms.

Description

Technical Field

[0001] The invention relates to the technical field of thickening, and in particular to a thickening paste and a preparation method thereof, and a viscosity regulating method of a pickling passivation liquid. Background Art

[0002] At present, there are many kinds of pickling and passivation products for stainless steel surface treatment, including pickling liquid, passivation liquid and liquid or paste integrating pickling and passivation with various formulas. Among them, pickling and passivation pastes are usually mixed with strong acid and gelling agent or filler. By mixing acid and gelling agent or filler, pickling substances will volatilize during its production and preparation process, which is harmful to the environment and construction workers. Summary of the invention

[0003] The purpose of the present invention is to provide a thickening paste and a preparation method thereof, and a viscosity adjustment method of a pickling passivation liquid, which are safe for the environment and construction workers, so as to solve the problems in the prior art.

[0004] To solve the above technical problems, the present invention adopts the following technical solution: a thickening paste, comprising, by weight percentage, 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier;

[0005] The first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form a water phase.

[0006] In one embodiment, the first emulsifier is insoluble in water;

[0007] The first emulsifier includes at least one of glyceryl monostearate, Tween, alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

[0008] In one embodiment, the second emulsifier includes at least one of sodium hydroxide, potassium hydroxide, Tweens, Spans, sodium dodecyl sulfate, and sodium dodecyl sulfate.

[0009] The present invention also provides a method for preparing a thickening paste, comprising the following steps:

[0010] According to weight percentage, 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier are weighed; wherein the first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form an aqueous phase;

[0011] The stearic acid and the first emulsifier are heated to 80-90° C., melted and mixed evenly to obtain an oil phase raw material;

[0012] The purified water and the second emulsifier are heated to 80-90° C., melted and mixed evenly to obtain a water phase raw material;

[0013] While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material, and after the addition is completed, the water phase raw material is emulsified at 80 to 90° C. and stirred for 10 to 15 minutes;

[0014] After cooling to 40° C., the thickened paste was obtained.

[0015] In one embodiment, during the emulsification process, the stirring speed is 1000-1500 r / min;

[0016] During the cooling process, reduce the stirring speed to 200-400r / min.

[0017] The present invention also provides a method for adjusting the viscosity of a pickling passivation liquid, wherein the viscosity is adjusted by uniformly mixing the thickening paste or the prepared thickening paste with the pickling passivation liquid.

[0018] In one embodiment, the weight ratio of the thickening paste to the pickling passivation solution is calculated based on the concentration of the pickling passivation solution and the pre-adjusted viscosity.

[0019] In one embodiment, the pickling passivation solution is added to the thickening paste and stirred evenly.

[0020] It can be seen from the above technical solution that the present invention has at least the following advantages and positive effects:

[0021] The thickening paste of the present invention comprises, by weight percentage, 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier; wherein the thickening paste does not contain toxic or harmful substances, does not release harmful gases, and is green and environmentally friendly.

[0022] The thickening paste is suitable for adjusting the viscosity of the pickling and passivation liquid, so that the pickling and passivation liquid can exist and act in different forms. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic flow diagram of the preparation method of the thickening paste in the present invention.

[0024] Figure 2 It is a schematic diagram of Example 1 of the present invention and the pickling passivation solution forming a paste.

[0025] Figure 3 It is a schematic diagram of applying the pickling passivating agent in the form of a paste formed by the pickling passivating liquid and the pickling passivating agent in Example 1 of the present invention to the weld.

[0026] Figure 4 It is a schematic diagram of the weld after being treated with a pickling passivating agent that forms a paste with a pickling passivating liquid in Example 1 of the present invention.

[0027] Figure 5 It is a schematic diagram of Example 1 in the present invention forming an emulsion with a pickling passivation solution.

[0028] Figure 6 It is a schematic diagram of spraying the pickling passivating agent in the form of an emulsion formed with the pickling passivating liquid in Example 1 of the present invention on the weld.

[0029] Figure 7 It is a schematic diagram of the weld after being treated with an emulsion-like pickling passivating agent formed with a pickling passivating liquid in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] Although the present invention can be easily embodied in different forms of embodiments, only some of the specific embodiments are shown in the drawings and will be described in detail in this specification. It should be understood that this description should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to that described herein.

[0031] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0032] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present invention are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0033] The invention provides a thickening paste which is non-toxic, pollution-free, releases no harmful gas and is green and environmentally friendly.

[0034] Specifically, the thickening paste includes, by weight percentage, 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier.

[0035] The first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form a water phase.

[0036] The chemical formula of stearic acid is C18 H 36 O2, white waxy transparent solid or slightly yellow waxy solid, can be dispersed into powder. Stearic acid is insoluble in water, with a melting point of 67-72°C. And stearic acid does not react with acid, so stearic acid is the main component of the thickening paste.

[0037] The structural formula of stearic acid is

[0038] The first emulsifier is insoluble in water and is mixed with stearic acid to form an oil phase.

[0039] The first emulsifier may be a nonionic emulsifier.

[0040] Specifically, the first emulsifier includes at least one of glyceryl monostearate, Tween, alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether. That is, the first emulsifier can be any one of the above, a mixture of any two of the above, or a mixture of any three, four or all of the above.

[0041] The second emulsifier is dissolved in water to form an aqueous phase. The second emulsifier may be a nonionic emulsifier or an ionic emulsifier. Specifically, the second emulsifier includes at least one of sodium hydroxide, potassium hydroxide, Tweens, Spans, sodium dodecyl sulfonate, and sodium dodecyl sulfate. That is, the second emulsifier may be any one of the above, or a mixture of any two of the above, or any three, other quantities, or a mixture of all of them.

[0042] The first emulsifier and the second emulsifier work together to evenly disperse the oil phase in the water phase, and disperse the water-insoluble stearic acid in the water in the form of small droplets to form an emulsion.

[0043] In the related art, the thickening mechanism of the thickener (such as macromolecular swelling, associated water molecules, etc.) is usually used to thicken the acid solution. However, the thickener is greatly affected by the pH value. The thickener will degrade and become ineffective in an acidic environment and cannot thicken.

[0044] The thickening paste in the present application is in a paste form and has stable performance. After being added to the pickling and passivation liquid, the solid content can be increased, and the viscosity of the thickening paste is relatively large, thereby being able to adjust the viscosity of the pickling and passivation liquid.

[0045] The thickened paste can be mixed with liquid, and the proportion can be selected according to specific needs.

[0046] In particular, the thickening paste is suitable for adjusting the viscosity of the pickling passivation liquid, so that the pickling passivation liquid can exist and act in different forms. For example, the thickening paste and the pickling passivation liquid form a paste that can be applied to the weld, and form an emulsion that can be sprayed.

[0047] The present invention also provides a method for preparing a thickening paste, comprising the following steps:

[0048] S1. According to weight percentage, weigh 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier; wherein the first emulsifier is dissolved in stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form an aqueous phase.

[0049] S2. Heat the stearic acid and the first emulsifier to 80-90° C., melt and mix evenly to obtain an oil phase raw material.

[0050] In the range of 80-90°C, stearic acid melts and becomes liquid. The first emulsifier is dissolved in the liquid stearic acid.

[0051] The melting and mixing may be performed under stirring.

[0052] S3, heating the purified water and the second emulsifier to 80-90° C., melting and mixing them evenly to obtain a water phase raw material.

[0053] After the purified water and the second emulsifier are heated, the precipitation of stearic acid when the water phase raw material is added to the oil phase raw material at a low temperature can be avoided.

[0054] S4. While the oil phase raw material is heated and stirred, slowly add the water phase raw material into the oil phase raw material. After the addition is completed, emulsify at 80-90° C. with stirring for 10-15 minutes.

[0055] Specifically, while the oil phase raw material is heated and stirred, the water phase raw material obtained in step S3 is slowly added until all of it is added. After the addition is completed, continue to heat and stir for emulsification for 10 to 15 minutes.

[0056] During the emulsification process, the stirring speed is 1000-1500r / min.

[0057] S5. After cooling to 40°C, a thickened paste is obtained.

[0058] Specifically, after the emulsification time is over, the temperature is lowered to obtain a thickened paste. It should be noted that when the temperature is lowered to 40°C, a thickened paste can be obtained. Then, when the temperature is lowered to below 40°C, a thickened paste can be obtained.

[0059] Before cooling, the stirring speed is also reduced to 200-400 r / min. That is, the stirring speed is kept low during the cooling process to ensure the uniformity of the thickened paste.

[0060] The process flow of the preparation method of the thickening paste is simple and easy to operate, and is convenient for production and processing.

[0061] The present invention also provides a method for adjusting the viscosity of a pickling passivation liquid, wherein the viscosity is adjusted by uniformly mixing the thickening paste with the pickling passivation liquid.

[0062] Specifically, the weight ratio of the thickening paste to the pickling passivation solution is calculated based on the concentration of the pickling passivation solution and the pre-adjusted viscosity.

[0063] Add the pickling and passivation liquid into the thickening paste and stir evenly to adjust the viscosity of the pickling and passivation liquid.

[0064] The inventors of the present application obtained a thickening paste by strictly designing the parameters of each component and the preparation method. The content of each component and the preparation method are introduced below through various examples.

[0065] Example 1

[0066] In terms of weight percentage, the thickening paste includes 20% of stearic acid, 1% of a first emulsifier, glyceryl monostearate, 78.8% of purified water, and 0.1% of a second emulsifier, sodium hydroxide.

[0067] The preparation method of the thickening paste comprises the following steps:

[0068] S11. According to weight percentage, weigh 20% of stearic acid, 1% of the first emulsifier glyceryl monostearate, 78.8% of pure water and 0.1% of the second emulsifier sodium hydroxide.

[0069] S12, heating stearic acid and the first emulsifier glyceryl monostearate to 80° C., melting and mixing evenly to obtain an oil phase raw material.

[0070] S13, heating the purified water and the second emulsifier sodium hydroxide to 80° C., melting and mixing them evenly to obtain a water phase raw material.

[0071] S14. While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material. After the addition is completed, emulsify at 80° C. with stirring for 10 minutes.

[0072] S15, after cooling to 40°C, a thickened paste is obtained.

[0073] Example 2

[0074] In terms of weight percentage, the thickening paste includes 30% of stearic acid, 1% of a first emulsifier Tween 60, 68.80% of purified water and 0.2% of a second emulsifier potassium hydroxide.

[0075] The preparation method of the thickening paste comprises the following steps:

[0076] S21. According to weight percentage, weigh 30% of stearic acid, 1% of the first emulsifier Tween, 68.80% of pure water and 0.2% of the second emulsifier potassium hydroxide.

[0077] S22, heating stearic acid and the first emulsifier Tween to 90° C., melting and mixing evenly to obtain an oil phase raw material.

[0078] S23, heating the purified water and the second emulsifier potassium hydroxide to 90° C., melting and mixing them evenly to obtain a water phase raw material.

[0079] S24. While the oil phase raw material is heated and stirred, slowly add the water phase raw material into the oil phase raw material. After the addition is completed, emulsify at 90° C. with stirring for 15 minutes.

[0080] S25, after cooling to 30°C, a thickened paste is obtained.

[0081] Example 3

[0082] In terms of weight percentage, the thickening paste comprises 25% of stearic acid, 2% of a first emulsifier, alkylphenol polyoxyethylene ether, 72.8% of purified water and 0.2% of a second emulsifier, Tween 20.

[0083] The preparation method of the thickening paste comprises the following steps:

[0084] S31, weigh 25% of stearic acid, 2% of the first emulsifier alkylphenol polyoxyethylene ether, 72.8% of purified water and 0.2% of the second emulsifier Tween 20.

[0085] S32, heating stearic acid and the first emulsifier alkylphenol polyoxyethylene ether to 85°C, melting and mixing evenly to obtain an oil phase raw material.

[0086] S33, heat the purified water and the second emulsifier Tween to 85°C, melt and mix evenly to obtain a water phase raw material.

[0087] S34. While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material. After the addition is completed, emulsify at 85° C. with stirring for 12 minutes.

[0088] S35, after cooling to 20°C, a thickened paste is obtained.

[0089] Example 4

[0090] In terms of weight percentage, the thickening paste includes 28% of stearic acid, 3% of a first emulsifier, fatty alcohol polyoxyethylene ether, 68.60% of purified water, and 0.4% of a second emulsifier, Span 40.

[0091] The preparation method of the thickening paste comprises the following steps:

[0092] S41, weigh 28% of stearic acid, 3% of the first emulsifier fatty alcohol polyoxyethylene ether, 68.60% of pure water and 0.4% of the second emulsifier Span 40.

[0093] S42, heating stearic acid and the first emulsifier fatty alcohol polyoxyethylene ether to 88° C., melting and mixing evenly to obtain an oil phase raw material.

[0094] S43, heating the purified water and the second emulsifier Span to 88° C., melting and mixing them evenly to obtain a water phase raw material.

[0095] S44. While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material. After the addition is completed, emulsify at 88° C. with stirring for 13 minutes.

[0096] S45, after cooling to 20°C, a thickened paste is obtained.

[0097] Example 5

[0098] In terms of weight percentage, the thickening paste comprises 20% of stearic acid, 5% of the first emulsifier alkylphenol polyoxyethylene ether, 0.5% of the first emulsifier fatty alcohol polyoxyethylene ether, 64.5% of purified water and 0.3% of the second emulsifier sodium dodecyl sulfate.

[0099] The preparation method of the thickening paste comprises the following steps:

[0100] S51, weigh 20% of stearic acid, 2% of the first emulsifier alkylphenol polyoxyethylene ether, 3% of the first emulsifier fatty alcohol polyoxyethylene ether, 64.5% of pure water and 0.3% of the second emulsifier sodium dodecyl sulfate.

[0101] S52, heating stearic acid and the first emulsifier alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether to 82° C., melting and mixing evenly to obtain an oil phase raw material.

[0102] S53, heating the purified water and the second emulsifier sodium dodecyl sulfate to 82° C., melting and mixing them evenly to obtain a water phase raw material.

[0103] S54. While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material. After the addition is completed, emulsify at 82° C. with stirring for 14 minutes.

[0104] S55, after cooling to 40°C, a thickened paste is obtained.

[0105] Example 6

[0106] In terms of weight percentage, the thickening paste includes 22% of stearic acid, 2.5% of a first emulsifier, alkylphenol polyoxyethylene ether, 75.20% of pure water, and 0.3% of a second emulsifier, sodium lauryl sulfate.

[0107] The preparation method of the thickening paste comprises the following steps:

[0108] S61. Weigh 22% of stearic acid, 2.5% of the first emulsifier alkylphenol polyoxyethylene ether, 75.20% of pure water and 0.3% of the second emulsifier sodium lauryl sulfate.

[0109] S62, heating stearic acid and the first emulsifier alkylphenol polyoxyethylene ether to 86°C, melting and mixing evenly to obtain an oil phase raw material.

[0110] S63, heating the purified water and the second emulsifier sodium lauryl sulfate to 86° C., melting and mixing them evenly to obtain a water phase raw material.

[0111] S64. While the oil phase raw material is heated and stirred, slowly add the water phase raw material into the oil phase raw material. After the addition is completed, emulsify at 82° C. with stirring for 11 minutes.

[0112] S65. After cooling to 10°C, a thickened paste is obtained.

[0113] Example 7

[0114] In terms of weight percentage, the thickening paste includes 23% of stearic acid, 4% of a first emulsifier, alkylphenol polyoxyethylene ether, 72.60% of pure water, 0.2% of a second emulsifier, sodium lauryl sulfate, and 0.2% of a second emulsifier, sodium hydroxide.

[0115] The preparation method of the thickening paste comprises the following steps:

[0116] S71. Weigh 23% of stearic acid, 4% of the first emulsifier alkylphenol polyoxyethylene ether, 72.60% of pure water, 0.2% of the second emulsifier sodium lauryl sulfate and 0.2% of the second emulsifier sodium hydroxide.

[0117] S72, heat stearic acid and the first emulsifier alkylphenol polyoxyethylene ether to 87° C., melt and mix evenly to obtain an oil phase raw material.

[0118] S73, heating the purified water, the second emulsifier sodium lauryl sulfate and sodium hydroxide to 86° C., melting and mixing them evenly to obtain a water phase raw material.

[0119] S74. While the oil phase raw material is heated and stirred, slowly add the water phase raw material into the oil phase raw material. After the addition is completed, emulsify at 85° C. with stirring for 13 minutes.

[0120] S75. After cooling to 15°C, a thickened paste is obtained.

[0121] Comparative Example 1

[0122] The pickling passivation paste used is HY-2A produced by Tianchang Huarun Cleaning Technology Co., Ltd.

[0123] Comparative Example 2

[0124] Calculated by weight percentage, the pickling passivation solution includes: 15-17.5% of aminosulfonic acid, 6-7% of fluorosilicic acid, 9-13% of citric acid, 3.6-4.2% of urotropine, and 53.2-62.6% of water.

[0125] The thickening pastes in Examples 1 to 7 were respectively mixed with the same pickling and passivating solution to adjust the viscosity of the pickling and passivating solution to obtain a pickling and passivating agent in a paste form.

[0126] The thickening pastes in Examples 1 to 7 were respectively mixed with the same pickling and passivating solution to adjust the viscosity of the pickling and passivating solution to obtain an emulsion-like pickling and passivating agent.

[0127] The weld is pickled and passivated using the above-mentioned different pickling and passivating agents, and the cleanliness of the weld after pickling and passivation is checked.

[0128] The mixed paste-like pickling passivating agent and the emulsion-like pickling passivating agent were applied to the stainless steel test plate, and after pickling for 50 minutes, they were washed with clean water and dried.

[0129] The treated stainless steel test plates were subjected to appearance observation and corrosion testing.

[0130] Appearance observation: Check whether it is clean and smooth, silvery white, and free of rust and oxides.

[0131] The corrosion rate is tested in accordance with GB / T 17897-2016 "Corrosion of Metals and Alloys - Ferric Chloride Pitting Corrosion Test Method for Stainless Steel".

[0132] The above pickling passivating agent was used to clean the stainless steel test plate after pickling, and the corrosion resistance and durability were checked. The results are shown in Table 1.

[0133] Table 1 Results of stainless steel test plates treated with pickling passivation agents in different states

[0134]

[0135] It can be seen from Table 1 that the combination of the thickening paste of Examples 1 to 7 and the pickling passivation solution can achieve the same pickling passivation effect as the prior art, and the thickening paste of the present application is non-toxic, non-polluting, does not release harmful gases, and is green and environmentally friendly.

[0136] Combination Figure 2 to Figure 4 It can be seen that the thickening paste can be mixed with the pickling passivation liquid to form a paste, so that the paste can be conveniently applied to the weld to be treated. After the pickling passivation is completed, it can be observed that the weld is clean and bright.

[0137] Combination Figure 5 to Figure 7 It can be seen that the thickening paste can be mixed with the pickling passivation liquid to form an emulsion-like substance, so that the emulsion-like substance can be conveniently sprayed on the weld to be treated. After the pickling passivation is completed, it can be observed that the weld is clean and bright.

[0138] Therefore, the thickening paste can adjust the viscosity of the pickling passivation solution, so that the pickling passivation solution can exist and act in different forms, and the passivation effect of the pickling passivation solution is basically not affected.

[0139] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A thickening paste, characterized in that: In terms of weight percentage, it comprises 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier; The first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form a water phase.

2. The thickening paste according to claim 1, characterized in that The first emulsifier is insoluble in water; The first emulsifier includes at least one of glyceryl monostearate, Tween, alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

3. The thickening paste according to claim 1, characterized in that The second emulsifier includes at least one of sodium hydroxide, potassium hydroxide, Tweens, Spans, sodium dodecyl sulfonate, and sodium dodecyl sulfate.

4. A method for preparing a thickening paste, characterized in that: The following steps are involved: According to weight percentage, 20-30% of stearic acid, 1-5% of a first emulsifier, 64.5-78.8% of pure water and 0.2-0.5% of a second emulsifier are weighed; wherein the first emulsifier is dissolved in the stearic acid to form an oil phase, and the second emulsifier is dissolved in water to form an aqueous phase; The stearic acid and the first emulsifier are heated to 80-90° C., melted and mixed evenly to obtain an oil phase raw material; The purified water and the second emulsifier are heated to 80-90° C., melted and mixed evenly to obtain a water phase raw material; While the oil phase raw material is heated and stirred, the water phase raw material is slowly added to the oil phase raw material, and after the addition is completed, the water phase raw material is emulsified at 80 to 90° C. and stirred for 10 to 15 minutes; After cooling to 40° C., the thickened paste is obtained.

5. The method for preparing a thickening paste according to claim 4, characterized in that: During the emulsification process, the stirring speed is 1000-1500r / min; During the cooling process, reduce the stirring speed to 200-400r / min.

6. A method for adjusting the viscosity of a pickling passivation solution, characterized in that: The viscosity is adjusted by uniformly mixing the thickening paste according to any one of claims 1 to 3 or the thickening paste prepared according to any one of claims 4 to 5 with the pickling passivation liquid.

7. The method for adjusting the viscosity of the pickling passivation solution according to claim 6, characterized in that: The weight ratio of the thickening paste to the pickling passivation solution is calculated based on the concentration of the pickling passivation solution and the pre-adjusted viscosity.

8. The method for adjusting the viscosity of the pickling passivation solution according to claim 6, characterized in that: Add the pickling passivation solution into the thickening paste and stir evenly.

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