A surface passivation method for high-purity manganese

Abstract

This invention relates to a surface passivation method for high-purity manganese. The surface passivation method includes the following steps: (1) rinsing the surface of high-purity manganese with isopropanol, and then immersing it in a passivation solution for surface passivation; (2) rinsing with isopropanol and vacuum drying to complete the surface passivation of high-purity manganese. The passivation solution comprises tannic acid, phytic acid, benzotriazole, imidazole, and hydrogen peroxide. The surface passivation method provided by this invention is for high-purity manganese products removed from the electrolytic cell after electrolytic preparation of high-purity manganese. This surface passivation method, through the use of a specific passivation solution, can not only ensure the surface passivation effect of high-purity manganese, but also ensure the purity of the obtained high-purity manganese, avoiding the adverse effects of the passivation solution on the purity of high-purity manganese.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic manganese production technology, and relates to a method for improving the purity of electrolytic manganese, and more particularly to a surface passivation method for electrolytic manganese. Background Technology

[0002] The industrial production of metallic manganese mainly adopts the electrolysis method. However, the electrolysis method produces manganese with impurities such as Fe, Zn, Mg, S, and Se. In order to optimize the production of chips below 28nm, the purity of high-purity manganese needs to reach 4N5 or higher, and the content of impurities such as C, N, O, H, and S needs to be less than 5ppm. This not only places high demands on the electrolysis process of metallic manganese, but also on the surface passivation method of electrolytic manganese.

[0003] In the current electrolytic manganese production process, the surface of electrolytic manganese fresh out of the electrolytic cell has a rich dendritic structure and a large specific surface area, which makes electrolytic manganese metal extremely prone to oxidation and discoloration in the air. Therefore, it is necessary to passivate the surface of electrolytic manganese.

[0004] CN115161628A discloses a passivating agent and passivation method for electrolytic manganese. The disclosed passivation method involves immersing electrolytic manganese in a passivation solution and performing passivation at a temperature of 40-95°C. The passivation solution is a dissolving oil (R-COO). - ) n M n+ An aqueous solution can form a passivation film on the surface of electrolyzed manganese metal. However, the passivation temperature of the passivation solution used is relatively high, which can easily generate environmentally harmful mists during the passivation process.

[0005] CN100422384A discloses a passivating agent and its preparation method for passivating the surface of electrolytic manganese metal. The disclosed passivating agent is mainly composed of silicates, fluxes, corrosion inhibitors, accelerators, and water. The weight percentages of each raw material are: silicates 70-80%, flux 0.1-0.2%, corrosion inhibitor 0.3-0.5%, accelerator 0.05-0.1%, and water as the balance, with the sum of the weight percentages being 100%. However, since the main component of the passivating agent is silicates, the passivation process still leads to an increase in metallic impurities and silicon content in the electrolytic manganese, which is detrimental to the application of electrolytic manganese in the semiconductor industry.

[0006] CN112195484A discloses a passivation-free process for producing electrolytic manganese and a post-processing method for the product, including the following steps: reacting manganese ore powder with sulfuric acid to obtain a manganese sulfate solution; neutralizing the tail acid with ammonia water; then purifying the manganese sulfate solution to remove iron, etc., to obtain a manganese sulfate solution containing ammonium sulfate; adding a certain concentration of selenium dioxide, surfactant, and organic polymer flocculant to this solution; electrolyzing to obtain manganese plates; removing the manganese plates from the electrolytic cell and directly entering a turbulent washing tank to clean the soluble sulfates on the surface of the manganese plates; then sending them to a low-temperature drying oven; after drying, automatic peeling is performed to obtain the passivation-free electrolytic manganese product. Although this method omits the subsequent passivation step through process improvement, it adds a large amount of additives during the electrolytic manganese production process, which is not conducive to obtaining high-purity manganese that meets the requirements of the semiconductor industry.

[0007] Therefore, there is a need for a surface passivation method suitable for high-purity manganese with a purity of 4N5 or higher, which not only has excellent passivation effect but is also environmentally friendly and can avoid the adverse effects of passivation on the purity of high-purity manganese. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a surface passivation method for electrolytic manganese, and more particularly, a surface passivation method for electrolytic manganese suitable for the semiconductor industry. This surface passivation method can ensure the surface passivation effect of high-purity manganese, as well as the purity of the obtained high-purity manganese, and avoid the adverse effects of the passivation solution on the purity of the high-purity manganese.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a method for surface passivation of high-purity manganese, the surface passivation method comprising the following steps:

[0011] (1) Rinse the surface of high-purity manganese with isopropanol, and then immerse it in passivation solution for surface passivation;

[0012] (2) Then rinse with isopropanol and vacuum dry to complete the surface passivation of high-purity manganese.

[0013] The passivation solution comprises tannic acid, phytic acid, benzotriazole (BTA), imidazole, and hydrogen peroxide.

[0014] The surface passivation method provided by this invention is for the high-purity manganese product removed from the electrolytic cell after the electrolytic preparation of high-purity manganese. This surface passivation method, through the use of a specific passivation solution, can not only ensure the surface passivation effect of high-purity manganese, but also ensure the purity of the obtained high-purity manganese, and avoid the adverse effects of the passivation solution on the purity of high-purity manganese.

[0015] The passivation solution provided by this invention uses deionized water as the solvent.

[0016] For example, in the surface passivation method provided by the present invention, isopropanol is electronic grade isopropanol; the purity of tannic acid, phytic acid, benzotriazole, imidazole and hydrogen peroxide is analytical grade or higher.

[0017] Preferably, based on a passivation solution mass percentage of 100%, the passivation solution contains 0.3-0.5% tannic acid, 0.5-1% phytic acid, 0.3-0.5% benzotriazole, 0.2-0.3% imidazole, and 0.1-0.2% hydrogen peroxide.

[0018] In this invention, the mass percentage of tannic acid in the passivation solution is 0.3-0.5%, for example, it can be 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] In this invention, the mass percentage of phytic acid in the passivation solution is 0.5-1%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] In this invention, the mass percentage of benzotriazole in the passivation solution is 0.3-0.5%, for example, it can be 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] In this invention, the mass percentage of imidazole in the passivation solution is 0.2-0.3%, for example, it can be 0.2%, 0.22%, 0.25%, 0.28% or 0.3%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] In this invention, the mass percentage of hydrogen peroxide in the passivation solution is 0.1-0.2%, for example, it can be 0.1%, 0.12%, 0.15%, 0.16%, 0.18% or 0.2%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] In this invention, the solvent for the passivation solution is water.

[0024] Preferably, the passivation solution further comprises ammonia.

[0025] For example, the purity of the ammonia solution of the present invention is analytical grade or higher.

[0026] This invention does not specifically limit the concentration of ammonia water, as long as the pH value of the passivation solution meets the process requirements.

[0027] Preferably, the ammonia content is such that the pH value of the passivation solution is 4-6, for example, it can be 4, 4.5, 5, 5.5 or 6, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the isopropanol rinsing time in step (1) is 1-2 min, for example, it can be 1 min, 1.2 min, 1.5 min, 1.6 min, 1.8 min or 2 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the soaking temperature in step (1) is 10-40℃, for example, it can be 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ or 40℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] The surface passivation method provided by this invention, through the use of a specific passivation liquid, enables surface passivation at a lower temperature, reducing the generation of aerosols that are detrimental to the environment.

[0031] Preferably, the soaking time in step (1) is 6-30s, for example, it can be 6s, 10s, 15s, 20s, 25s or 30s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the rinsing time in step (2) is 2-3 minutes, for example, it can be 2 minutes, 2.2 minutes, 2.5 minutes, 2.7 minutes, 2.8 minutes or 3 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the vacuum degree of vacuum drying in step (2) is ≤-0.08MPa, for example, it can be -0.09MPa, -0.088MPa, -0.085MPa, -0.082MPa or -0.08MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the vacuum drying temperature in step (2) is 50-70℃ and the time is 100-150s.

[0035] In this invention, the vacuum drying temperature is 50-70℃, for example, it can be 50℃, 55℃, 60℃, 65℃ or 70℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] In this invention, the vacuum drying time is 100-150s, for example, it can be 100s, 110s, 120s, 130s, 140s or 150s, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the purity of the high-purity manganese in step (1) is 4N5 or higher.

[0038] As a preferred embodiment of the surface passivation method of the present invention, the surface passivation method includes the following steps:

[0039] (1) Rinse the surface of high-purity manganese with isopropanol (4N5 or higher) for 1-2 minutes, then immerse it in a passivation solution at 10-40℃ for 6-30 seconds to passivate the surface.

[0040] (2) Then rinse with isopropanol for 2-3 minutes and vacuum dry to complete the surface passivation of high-purity manganese;

[0041] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.3-0.5% tannic acid, 0.5-1% phytic acid, 0.3-0.5% benzotriazole, 0.2-0.3% imidazole, and 0.1-0.2% hydrogen peroxide.

[0042] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 4-6.

[0043] The vacuum drying process in step (2) has a vacuum degree of ≤-0.08MPa, a temperature of 50-70℃, and a time of 100-150s.

[0044] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] The surface passivation method provided by this invention is for the high-purity manganese product removed from the electrolytic cell after the electrolytic preparation of high-purity manganese. This surface passivation method, through the use of a specific passivation solution, can not only ensure the surface passivation effect of high-purity manganese, but also ensure the purity of the obtained high-purity manganese, and avoid the adverse effects of the passivation solution on the purity of high-purity manganese. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0048] To facilitate the explanation of the technical solution of the present invention, the high-purity manganese in the specific embodiment is 20cm×25cm×2mm. This size is only for the purpose of clearly explaining the technical solution and is not considered as a further limitation on the surface passivation method of the present invention.

[0049] Example 1

[0050] This embodiment provides a surface passivation method for high-purity manganese, the surface passivation method comprising:

[0051] (1) Rinse the surface of high-purity manganese with isopropanol for 1.5 min, and then immerse it in passivation solution at 25℃ for 15 s to passivate the surface;

[0052] (2) Then rinse with isopropanol for 2.5 min and vacuum dry to complete the surface passivation of high-purity manganese;

[0053] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.4% benzotriazole, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0054] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 5.

[0055] The vacuum degree of the vacuum drying in step (2) is -0.08MPa, the temperature is 60℃, and the time is 120s.

[0056] Example 2

[0057] This embodiment provides a surface passivation method for high-purity manganese, the surface passivation method comprising:

[0058] (1) Rinse the surface of high-purity manganese with isopropanol for 1.5 min, and then immerse it in passivation solution at 25℃ for 15 s to passivate the surface;

[0059] (2) Then rinse with isopropanol for 2.5 min and vacuum dry to complete the surface passivation of high-purity manganese;

[0060] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.3% tannic acid, 0.5% phytic acid, 0.3% benzotriazole, 0.2% imidazole, and 0.1% hydrogen peroxide.

[0061] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 4.

[0062] The vacuum degree of the vacuum drying in step (2) is -0.08MPa, the temperature is 60℃, and the time is 120s.

[0063] Example 3

[0064] This embodiment provides a surface passivation method for high-purity manganese, the surface passivation method comprising:

[0065] (1) Rinse the surface of high-purity manganese with isopropanol for 1.5 min, and then immerse it in passivation solution at 25℃ for 15 s to passivate the surface;

[0066] (2) Then rinse with isopropanol for 2.5 min and vacuum dry to complete the surface passivation of high-purity manganese;

[0067] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.5% tannic acid, 1% phytic acid, 0.5% benzotriazole, 0.3% imidazole, and 0.2% hydrogen peroxide.

[0068] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 6.

[0069] The vacuum degree of the vacuum drying in step (2) is -0.08MPa, the temperature is 60℃, and the time is 120s.

[0070] Example 4

[0071] This embodiment provides a surface passivation method for high-purity manganese, the surface passivation method comprising:

[0072] (1) Rinse the surface of high-purity manganese with isopropanol for 1 min, and then immerse it in a passivation solution at 10℃ for 30 s to passivate the surface.

[0073] (2) Then rinse with isopropanol for 2 minutes and vacuum dry to complete the surface passivation of high-purity manganese.

[0074] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.4% benzotriazole, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0075] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 5.

[0076] The vacuum degree of the vacuum drying in step (2) is -0.08MPa, the temperature is 50℃, and the time is 150s.

[0077] Example 5

[0078] This embodiment provides a surface passivation method for high-purity manganese, the surface passivation method comprising:

[0079] (1) Rinse the surface of high-purity manganese with isopropanol for 2 min, and then immerse it in a passivation solution at 40℃ for 6 s to passivate the surface.

[0080] (2) Then rinse with isopropanol for 3 minutes and vacuum dry to complete the surface passivation of high-purity manganese.

[0081] Based on a passivation solution mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.4% benzotriazole, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0082] The passivation solution also includes ammonia water, and the ammonia water content is such that the pH value of the passivation solution is 5.

[0083] The vacuum degree of the vacuum drying in step (2) is -0.08MPa, the temperature is 70℃, and the time is 100s.

[0084] Example 6

[0085] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of tannic acid in the passivation solution is 0.2%, everything else is the same as in Example 1.

[0086] Example 7

[0087] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of tannic acid in the passivation solution is 0.6%, everything else is the same as in Example 1.

[0088] Example 8

[0089] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of phytic acid in the passivation solution is 0.3%, everything else is the same as in Example 1.

[0090] Example 9

[0091] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of phytic acid in the passivation solution is 1.2%, everything else is the same as in Example 1.

[0092] Example 10

[0093] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of benzotriazole in the passivation solution is 0.2%, everything else is the same as in Example 1.

[0094] Example 11

[0095] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of benzotriazole in the passivation solution is 0.6%, everything else is the same as in Example 1.

[0096] Example 12

[0097] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of imidazole in the passivation solution is 0.1%, everything else is the same as in Example 1.

[0098] Example 13

[0099] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of imidazole in the passivation solution is 0.4%, everything else is the same as in Example 1.

[0100] Example 14

[0101] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of hydrogen peroxide in the passivation solution is 0.1%, everything else is the same as in Example 1.

[0102] Example 15

[0103] This embodiment provides a surface passivation method for high-purity manganese. Except that the mass percentage of hydrogen peroxide in the passivation solution is 0.4%, everything else is the same as in Example 1.

[0104] Comparative Example 1

[0105] This comparative example provides a surface passivation method for high-purity manganese. Except for the composition of the passivation solution, which is different from that of Example 1, everything else is the same as that of Example 1.

[0106] In this comparative example, with the passivation solution having a mass percentage of 100%, the passivation solution contains 0.8% phytic acid, 0.4% benzotriazole, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0107] The passivation solution also includes ammonia water, the amount of which is such that the pH value of the passivation solution is 5.

[0108] Comparative Example 2

[0109] This comparative example provides a surface passivation method for high-purity manganese. Except for the composition of the passivation solution, which is different from that of Example 1, everything else is the same as that of Example 1.

[0110] In this comparative example, with the passivation solution having a mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.4% benzotriazole, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0111] The passivation solution also includes ammonia water, the amount of which is such that the pH value of the passivation solution is 5.

[0112] Comparative Example 3

[0113] This comparative example provides a surface passivation method for high-purity manganese. Except for the composition of the passivation solution, which is different from that of Example 1, everything else is the same as that of Example 1.

[0114] In this comparative example, with the passivation solution having a mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.25% imidazole, and 0.15% hydrogen peroxide.

[0115] The passivation solution also includes ammonia water, the amount of which is such that the pH value of the passivation solution is 5.

[0116] Comparative Example 4

[0117] This comparative example provides a surface passivation method for high-purity manganese. Except for the composition of the passivation solution, which is different from that of Example 1, everything else is the same as that of Example 1.

[0118] In this comparative example, with the passivation solution having a mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.4% benzotriazole, and 0.15% hydrogen peroxide.

[0119] The passivation solution also includes ammonia water, the amount of which is such that the pH value of the passivation solution is 5.

[0120] Comparative Example 5

[0121] This comparative example provides a surface passivation method for high-purity manganese. Except for the composition of the passivation solution, which is different from that of Example 1, everything else is the same as that of Example 1.

[0122] In this comparative example, with the passivation solution having a mass percentage of 100%, the passivation solution contains 0.4% tannic acid, 0.8% phytic acid, 0.4% benzotriazole, and 0.25% imidazole.

[0123] The passivation solution also includes ammonia water, the amount of which is such that the pH value of the passivation solution is 5.

[0124] Comparative Example 6

[0125] This comparative example provides a surface passivation method for high-purity manganese, which is the same as in Example 1 except that the passivation solution is replaced with the traditional 5wt% potassium dichromate.

[0126] Blank comparison example

[0127] The surface of high-purity manganese was rinsed with isopropanol for 2.5 minutes and then vacuum dried. The vacuum drying was carried out at a vacuum degree of -0.08 MPa, a temperature of 60°C, and a time of 120 seconds.

[0128] The purity and the time when the surface began to blacken of the high-purity manganese after treatment in the above examples, comparative examples, and blank control examples were recorded. The purity was determined by GDMS (glow discharge mass spectrometry), and the results are shown in Table 1. In Table 1, the dimensions of K content, Cr content, Si content, P content, S content, Fe content, and Se content are ppm, the dimension of purity is wt%, and the dimension of the time when the surface began to blacken is days.

[0129] Table 1

[0130]

[0131] In summary, the surface passivation method provided by this invention is for processing high-purity manganese products removed from the electrolytic cell after electrolytic preparation of high-purity manganese. This surface passivation method, through the use of a specific passivation solution, can not only ensure the surface passivation effect of high-purity manganese, but also ensure the purity of the obtained high-purity manganese, avoiding the adverse effects of the passivation solution on the purity of high-purity manganese.

[0132] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for surface passivation of high-purity manganese, characterized in that, The surface passivation method includes the following steps: (1) Rinse the surface of high-purity manganese with isopropanol, and then immerse it in passivation solution for surface passivation; (2) Then rinse with isopropanol and vacuum dry to complete the surface passivation of high-purity manganese; The passivation solution is composed of tannic acid, phytic acid, benzotriazole, imidazole, hydrogen peroxide, and ammonia; the solvent of the passivation solution is water. The passivation solution contains 0.3-0.5% tannic acid, 0.5-1% phytic acid, 0.3-0.5% benzotriazole, 0.2-0.3% imidazole, and 0.1-0.2% hydrogen peroxide by mass. The soaking temperature in step (1) is 10-40℃.

2. The surface passivation method according to claim 1, characterized in that, The ammonia content is such that the pH value of the passivation solution is 4-6.

3. The surface passivation method according to claim 1, characterized in that, The isopropanol rinsing time in step (1) is 1-2 minutes.

4. The surface passivation method according to claim 1, characterized in that, The soaking time in step (1) is 6-30 seconds.

5. The surface passivation method according to claim 1, characterized in that, The rinsing time in step (2) is 2-3 minutes.

6. The surface passivation method according to claim 1, characterized in that, The vacuum degree of the vacuum drying in step (2) is ≤-0.08MPa.

7. The surface passivation method according to claim 1, characterized in that, The vacuum drying temperature in step (2) is 50-70℃ and the time is 100-150s.

8. The surface passivation method according to claim 1, characterized in that, The purity of the high-purity manganese in step (1) is above 4N5.

9. The surface passivation method according to claim 1, characterized in that, The surface passivation method includes the following steps: (1) Rinse the surface of high-purity manganese with isopropanol (4N5 or higher) for 1-2 minutes, then immerse it in passivation solution at 10-40℃ for 6-30 seconds to passivate the surface. (2) Then rinse with isopropanol for 2-3 minutes, and vacuum dry to complete the surface passivation of high-purity manganese; The passivation solution contains 0.3-0.5% tannic acid, 0.5-1% phytic acid, 0.3-0.5% benzotriazole, 0.2-0.3% imidazole, and 0.1-0.2% hydrogen peroxide by mass. The ammonia content in the passivation solution is such that the pH value of the passivation solution is 4-6; In step (2), the vacuum drying process requires a vacuum degree of ≤-0.08MPa, a temperature of 50-70℃, and a time of 100-150s.

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