Aluminum electrolytic carbon anode anticorrosion coating and preparation method thereof

Abstract

The application discloses an aluminum electrolysis carbon anode anti-oxidation anticorrosion coating and a preparation method thereof. The coating comprises the following components in percentage by mass: a main component 30-40%, a secondary component 15-25%, a binder 10-15%, an anticorrosion additive 15-25%, and the balance is water. The main component comprises white corundum powder, red corundum powder and microcrystalline corundum powder. The secondary component comprises secondary component 1 and secondary component 2. The secondary component 1 comprises phlogopite, biotite and sodium mica. The secondary component 2 comprises potassium feldspar, sodium feldspar and calcium feldspar. The binder is sodium water glass and potassium water glass. The aluminum electrolysis carbon anode anti-oxidation anticorrosion coating is simple and convenient to prepare. After being coated on the carbon anode, the carbon anode in operation can be well protected. The weight loss rate of each sample is only about 0.8%, and the problems of anode oxidation and coating corrosion are effectively reduced.

Description

Technical Field

[0001] The invention discloses an anti-oxidation and anti-corrosion coating for an aluminum electrolysis carbon anode and a preparation method thereof, and belongs to the field of aluminum electrolysis, in particular to the field of carbon anode protection. Technical Background

[0002] Aluminum and aluminum alloys are widely used in aerospace, construction, transportation, electronics, communications, defense, and military industries due to their low density, high specific strength, corrosion resistance, ease of processing, good thermal and electrical conductivity, and recyclability. Modern electrolytic aluminum production utilizes cryolite-alumina molten salt electrolysis, with carbonite as the anode and molten aluminum as the cathode. After a strong direct current is applied, an electrochemical reaction occurs at the two electrodes in the electrolytic cell at temperatures between 800°C and 960°C. The chemical reaction is primarily carried out according to the following equation: 2Al2O3+3C==4Al+3CO2↑,

[0003] ˉ-ˉ

[0004] Anode: 2O 2 +C-4e=CO2↑, cathode:Al 3+ +3e=Al. Carbon anodes are crucial for aluminum electrolysis. Currently, the production of one ton of metallic aluminum consumes 470 kilograms of carbon anodes, 30% more than the theoretical consumption. This is because after the carbon anodes are installed in the electrolytic cell, they are exposed to elevated temperatures (over 900°C) due to increased cell temperature and electrical conductivity. These temperatures cause the carbon anodes to oxidize when exposed to air and gases produced by electrolysis, such as carbon dioxide, carbon monoxide, and hydrogen fluoride. This oxidation leads to chemical consumption and the shedding of carbon particles, forming carbon slag. To reduce this high-temperature oxidation loss and lower the production cost of electrolytic aluminum, a currently cost-effective method is to apply a protective coating to the surface of the carbon anodes. This reduces the loss of the carbon anodes caused by high-temperature oxidation by air, thereby extending their service life.

[0005] At present, most aluminum electrolysis plants use a coating method to ensure that the carbon anode is isolated from the air, thereby avoiding additional losses caused by chemical consumption between the carbon anode and the air at high temperatures. However, they all have their defects. For example, the coating invented by the patent published in CN201510442632 has too low an aluminum oxide content, resulting in poor oxidation resistance of the coating and a short shelf life. The coating invented by the patent published in CN202110738852 contains compounds such as boric acid and boric acid, which will have a certain impact on the electrolyte of electrolytic aluminum and reduce the electrolysis efficiency. In addition, these coatings also ignore the corrosion of fluorides generated in the production environment to the coating, which causes the coating performance to deteriorate and affects the anti-oxidation effect.

[0006] To prevent high-temperature surface oxidation corrosion of carbon anodes, the present invention provides a coating that forms a dense insulating layer on the carbon anode surface, preventing oxidation between air and the carbon anode, which would otherwise lead to excessive consumption. Furthermore, in aluminum electrolysis environments, the coating is effectively protected against electrolyte corrosion. Experimental calculations show a weight loss rate of only 0.8%, significantly reducing the cost of aluminum electrolysis. Summary of the Invention

[0007] To address the above issues, the present invention aims to provide an anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anodes and a method for preparing the same. The provided anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anodes is simple and convenient to prepare. After being applied to the carbon anode, the coating exhibits a low sintering temperature and a short curing time. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anodes provides excellent protection for the carbon anode during operation. The calculated weight loss rate of the samples in each embodiment is only approximately 0.8%, effectively alleviating issues such as anodic oxidation and coating corrosion.

[0008] The technical solution adopted by the present invention is as follows:

[0009] An anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anodes, comprising the following components by mass percentage: 30% to 40% of a main component, 15% to 25% of a secondary component, 10% to 15% of a binder, 15% to 25% of an anti-corrosion additive, and the balance being water;

[0010] The main components include white corundum powder, red corundum powder and microcrystalline corundum powder;

[0011] The subcomponents include subcomponent 1 and subcomponent 2, subcomponent 1 includes phlogopite, biotite and sodium mica; subcomponent 2 includes potassium feldspar, sodium feldspar and calcium feldspar;

[0012] The binder is sodium water glass and potassium water glass;

[0013] The anti-corrosion additive includes one or more of anti-corrosion additive 1, anti-corrosion additive 2 and anti-corrosion additive 3; anti-corrosion additive 1 includes one or more of fluorinated graphite, fluorinated carbon black, fluorinated carbon fiber, fluorinated graphite microsheets, and fluorinated graphene; anti-corrosion additive 2 includes one or more of methyl trifluoroacrylate, perfluoromethyl acrylate, ethyl trifluoroacrylate, and perfluoroethyl acrylate; anti-corrosion additive 3 includes one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDV), and polyvinyl fluoride (PVF).

[0014] Furthermore, the main component is composed of raw materials in the following mass ratio: 40% to 60% white corundum powder, 30% to 40% red corundum powder, and 10% to 22% microcrystalline corundum powder.

[0015] Furthermore, the white corundum powder has an Al2O3 content of 95% to 99%, a Na2O content of 0.01% to 0.05%, and a particle size between 180 mesh and 300 mesh; the red corundum powder has an Al2O3 content of 90% to 95%, a Cr2O3 content of 1% to 3%, and a particle size between 100 mesh and 200 mesh; the microcrystalline corundum powder has an Al2O3 content of 91% to 94%, a TiO2 content of 0.5% to 2%, and a particle size between 200 mesh and 300 mesh.

[0016] Furthermore, the subcomponent is composed of raw materials in the following mass ratios: phlogopite 7% to 19%, biotite 12% to 20%, sodium mica 14% to 25%, potassium feldspar 14% to 28%, sodium feldspar 8% to 26%, and calcium feldspar 13% to 30%.

[0017] Furthermore, the binder is composed of the following raw materials in the following mass ratio: 67% to 80% of sodium water glass and 20% to 33% of potassium water glass.

[0018] Furthermore, the sodium water glass has a Na2O content of 4% to 10%, a SiO2 content of 15% to 44%, and the balance is deionized water; the potassium water glass has a K2O content of 3% to 10%, a SiO2 content of 15% to 45%, and the balance is deionized water.

[0019] Furthermore, the anti-corrosion additive 1 is composed of the following raw materials in the following mass ratios: 0% to 20% of fluorinated graphite, 0% to 25% of fluorinated carbon black, 0% to 30% of fluorinated carbon fiber, 0% to 30% of fluorinated graphite microflakes, and 0% to 25% of fluorinated graphene; the anti-corrosion additive 2 is composed of the following raw materials in the following mass ratios: 0% to 40% of methyl trifluoroacrylate, 0% to 40% of perfluoromethyl acrylate, 0% to 30% of ethyl trifluoroacrylate, and 0% to 30% of perfluoroethyl acrylate; the anti-corrosion additive 3 is composed of the following raw materials in the following mass ratios: 0% to 60% of polytetrafluoroethylene (PTFE), 0% to 60% of polyvinylidene fluoride (PVDV), and 0% to 60% of polyvinyl fluoride (PVF).

[0020] Most preferably, the carbon anode anti-oxidation and anti-corrosion coating comprises the following components by mass: a main component (30.7%-38%), a secondary component (17%-22%), a binder (10.9%-14%), an anti-corrosion additive (17%-25%), and the balance (water). The main component is composed of the following raw materials in the following mass ratios: white corundum powder (42%-56%), red corundum powder (32%-38%), and microcrystalline corundum powder (12%-20%). The secondary components are composed of the following raw materials in the following mass ratios: phlogopite (11%-18%), biotite (12%-18%), sodium mica (16%-25%), potassium feldspar (21%-28%), sodium feldspar (21%-26%), and anorthite (13%-18%). The binder is composed of the following raw materials in the following mass ratios: sodium water glass (72%-78%) and potassium water glass (22%-27%). The anti-corrosion additive with a content of 17% to 25% is composed of raw materials in the following mass ratio: anti-corrosion additive 1 with a content of 8% to 13%, anti-corrosion additive 2 with a content of 4% to 13%, and anti-corrosion additive 3 with a content of 5% to 10%.

[0021] The method for preparing an anti-oxidation and anti-corrosion coating for an aluminum electrolytic carbon anode comprises the following specific steps: first weighing the raw materials of each component, mixing the main component with the secondary component to obtain a mixture A, mixing the binder and the anti-corrosion additive to obtain a mixture B, then pouring the mixture A, the mixture B and water into a stirring tank in sequence, and stirring them thoroughly to obtain the anti-oxidation and anti-corrosion coating.

[0022] Furthermore, the preparation of mixture A is specifically as follows: white corundum powder, red corundum powder, microcrystalline corundum powder, phlogopite, biotite, sodium mica, potassium feldspar, sodium feldspar, and calcium feldspar are sequentially put into a powder machine, and the machine is started for 2 to 6 hours to obtain mixture A;

[0023] The preparation of mixture B is specifically as follows: sodium water glass, potassium water glass, anticorrosive additives and an appropriate amount of water are sequentially put into a magnetic stirrer, stirred at a temperature of 20 to 60° C., preferably 30 to 80° C., and a stirring speed of 200 to 600 rpm for 1 to 5 hours, preferably 3 to 6 hours, to obtain mixture B.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] 1) The prepared coating contains a high content of aluminum oxide components, which can effectively wrap the carbon anode, block the erosion of oxygen, greatly reduce the oxidation rate, and have a good anti-oxidation effect; the prepared coating contains a moderate content of silicon oxide components, the coating has good extensibility, can effectively prevent the coating from settling, and greatly extend the shelf life of the coating; the prepared coating does not contain sulfur, phosphorus and other substances, will not produce substances harmful to electrolysis, and will not affect the efficiency of electrolytic aluminum; the prepared coating contains little metal other than aluminum, and is very effective in preventing metal corrosion; the prepared coating contains fluorinated materials, which are resistant to corrosive chemicals such as strong acids, strong alkalis and strong oxidants, and are tightly arranged on the coating surface, which can effectively prevent the fluorides generated by the electrolytic environment from corroding the coating material.

[0026] 2) In addition, the anti-oxidation and anti-corrosion coating prepared by the present invention also has great advantages in practical application: the preparation of the coating of the present invention does not use expensive raw materials such as nanomaterials, and the cost of the prepared coating is only 5-7 yuan per kilogram; after the coating is coated on the surface of the carbon anode, the weight loss rate of the carbon anode of each embodiment is calculated to be only 0.8%; the raw materials required for the coating prepared by the present invention are widely available, the preparation is simple, and it is easy to promote. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0028] The white corundum powder, red corundum powder, and microcrystalline corundum powder used in the examples of this invention were all purchased from Zhengzhou Rongsheng Kiln Engineering Technology Co., Ltd. Phlogopite, biotite, sodium mica, potassium feldspar, sodium feldspar, and calcium feldspar were all purchased from Anhui Gerui New Materials Technology Co., Ltd. Anti-corrosion additives were purchased from Fuzhou Taipuda New Materials Co., Ltd. The carbon anode material was blast furnace carbon blocks.

[0029] Example 1

[0030] Disclosed is an anti-oxidation and anti-corrosion coating for an aluminum electrolytic carbon anode, which comprises, by weight percentage, a main component, a secondary component, a binder, and anti-corrosion additive materials: the main component comprises 30.7%, of which white corundum powder comprises 13.8%, red corundum powder comprises 11.1%, and microcrystalline corundum powder comprises 5.8%; the secondary component 1 comprises 8.3%, of which phlogopite comprises 2.3%, biotite comprises 3.0%, and sodium mica comprises 3.0%; the secondary component 2 comprises 10.5%, of which potassium feldspar comprises 4.5%, sodium feldspar comprises 4.1%, and anorthite comprises 1.9%; the binder comprises 11.5%, of which sodium water glass comprises 8.7%, and potassium water glass comprises 2.8%; the anti-corrosion additive 1 comprises 22.9%, of which fluorinated carbon black comprises 4.8%, carbon fiber comprises 5.7%, graphite fluoride microplatelets comprises 6.8%, and graphene fluoride comprises 5.6%; the contents of both anti-corrosion additives 2 and 3 are 0%; the remainder is water, and the total addition amount is 100%.

[0031] Sodium water glass is composed of the following raw materials by weight percentage: Na2O 10%, SiO2 40%, and the balance water. Potassium water glass is composed of the following raw materials by weight percentage: K2O 10%, SiO2 45%, and the balance water.

[0032] First, corundum powder, phlogopite, biotite, sodium mica, potassium feldspar, sodium feldspar, and calcium feldspar were added to a powder machine in sequence. The powder machine was started and crushed for 4 hours, and then a mixture A with a mesh size of 220 was collected. Then, sodium water glass, potassium water glass, an anti-corrosion additive, and an appropriate amount of water were added to a magnetic stirrer, stirred at a temperature of 30°C and a stirring speed of 400 rpm for 4 hours to obtain a mixture B. Then, mixtures A, B, and water were poured into a stirring kettle in sequence, stirred at a temperature of 50°C, a stirring speed of 500 rpm, and a stirring time of 5 hours. After thorough stirring, an anti-oxidation and anti-corrosion coating was obtained.

[0033] The anti-oxidation and anti-corrosion coating of Example 1 was applied to the surface of the carbon anode and sintered at 410°C in a hydrogen atmosphere for 2 hours. It was found that the coating was tightly wrapped on the surface of the carbon anode without falling off. The coating thickness on the surface of the carbon anode was 13 μm.

[0034] The coated carbon anode from Example 1 was placed in a tube furnace set to 910°C and fed with CO2 gas at a constant temperature of 1 mL / min for 72 hours to simulate oxidation of the carbon anode during electrolysis. The calculated weight loss after the test was only 0.80%. The coating was tested again after 3 months, and the weight loss was 0.81%. The coating was tested again after 6 months, and the weight loss was 0.83%.

[0035] Weight loss rate = (M 测试前 -M 测试后 ) / M 测试前 ×100%.

[0036] The coated carbon anode from Example 1 was also tested for electrode efficiency. The test conditions were as follows: cryolite-alumina was added to a graphite electrolytic cell and heated to 900°C to melt the alumina (the cryolite is used to lower the melting point of the alumina and does not participate in the electrolysis process). The lower end of the coated carbon anode was then inserted into the molten electrolyte. The upper end of the carbon anode was connected to the positive electrode of a power supply via a wire, and the negative electrode of the power supply was directly connected to the top of the graphite electrolytic cell via a wire. Electrolysis was carried out under power at a current of 60 kA. The aluminum deposited by electrolysis was deposited in the lower layer of the electrolyte. The aluminum product at the bottom was removed, cooled, and weighed.

[0037] After an aluminum plant applied the coating on the carbon anode, it was tested in a small side-insertion rod self-baking anode aluminum electrolysis below 60kA. The current efficiency of the electrolytic aluminum was 87.2%, with no obvious change.

[0038] Current efficiency = mass of aluminum actually deposited by electrolysis / mass of aluminum theoretically deposited by electrolysis × 100% (electrolysis time is 24 hours).

[0039] Example 2

[0040] Disclosed is an anti-oxidation and anti-corrosion coating for an aluminum electrolytic carbon anode, which comprises, by weight percentage, a main component, a secondary component, a binder, and anti-corrosion additive materials: the main component comprises 31.1%, of which white corundum powder comprises 17.4%, red corundum powder comprises 10.0%, and microcrystalline corundum powder comprises 3.7%; the secondary component 1 comprises 8.6%, of which phlogopite comprises 2.2%, biotite comprises 3.2%, and sodium mica comprises 3.2%; the secondary component 2 comprises 11.5%, of which potassium feldspar comprises 4.8%, sodium feldspar comprises 4.4%, and calcium feldspar comprises 2.2%; the binder comprises 10.9%, of which sodium water glass comprises 7.7%, and potassium water glass comprises 3.2%; the anti-corrosion additive 2 comprises 18.1%, of which methyl trifluoroacrylate comprises 4.6%, methyl perfluoroacrylate comprises 5.4%, ethyl trifluoroacrylate comprises 4.5%, and ethyl perfluoroacrylate comprises 3; the contents of both anti-corrosion additives 1 and 3 are 0%; the remainder is water, and the total addition amount is 100%.

[0041] Sodium water glass is composed of the following raw materials by weight percentage: Na2O4%, SiO244%, and the balance water. Potassium water glass is composed of the following raw materials by weight percentage: K2O5%, SiO239%, and the balance water.

[0042] Example 2 The preparation method of the anti-oxidation and anti-corrosion coating is repeated in Example 1.

[0043] The anti-oxidation and anti-corrosion coating of Example 2 was applied to the surface of the carbon anode and sintered at 410°C in a hydrogen atmosphere for 2 hours. It was found that the coating was tightly wrapped on the surface of the carbon anode without falling off. The coating thickness on the surface of the carbon anode was 13 μm.

[0044] The coated carbon anodes of Example 2 were subjected to high-temperature oxidation and current efficiency tests, using the same testing conditions as in Example 1. After the high-temperature oxidation test, the calculated weight loss was only 0.79%. The coating was tested again after three months of storage, and the weight loss was 0.81%. The coating was tested again after six months of storage, and the weight loss was 0.82%. An aluminum plant applied this coating in a small, side-inserted, self-baking anode aluminum electrolysis system operating at less than 60 kA. The current efficiency of the electrolytic aluminum was 88.2%, showing no significant change.

[0045] Example 3

[0046] Disclosed is an anti-oxidation and anti-corrosion coating for an aluminum electrolytic carbon anode, which comprises, by weight percentage, a main component, a secondary component, a binder, and anti-corrosion additive materials: the main component content is 32.1%, of which white corundum powder is 14.8%, red corundum powder is 10.9%, and microcrystalline corundum powder is 6.4%; the secondary component 1 content is 10.2%, of which phlogopite is 2.8%, biotite is 3.7%, and sodium mica is 3.7%; the secondary component 2 content is 13.0%, of which potassium feldspar is 56%, sodium feldspar is 5.1%, and calcium feldspar is 5.3%; the binder content is 12.9%, of which sodium water glass is 8.7% and potassium water glass is 4.2%; the anti-corrosion additive 3 content is 17.0%, of which polytetrafluoroethylene (PTFE) is 4.4%, polyvinylidene fluoride (PVDV) is 7.3%, and polyvinyl fluoride (PVF) is 5.3%; the content of anti-corrosion additives 1 and 2 is both 0; the balance is water, and the total added amount is 100%.

[0047] Sodium water glass is composed of the following raw materials by weight percentage: Na2O 8%, SiO2 30%, and the balance water. Potassium water glass is composed of the following raw materials by weight percentage: K2O 5%, SiO2 40%, and the balance water.

[0048] Example 3 The preparation method of the anti-oxidation and anti-corrosion coating is repeated in Example 1.

[0049] The anti-oxidation and anti-corrosion coating of Example 3 was applied to the surface of the carbon anode and sintered at 410°C in a hydrogen atmosphere for 2 hours. It was found that the coating was tightly wrapped on the surface of the carbon anode without falling off. The coating thickness on the surface of the carbon anode was 13 μm.

[0050] The coated carbon anodes of Example 3 were subjected to high-temperature oxidation and current efficiency tests, using the same testing conditions as in Example 1. After the high-temperature oxidation test, the calculated weight loss was only 0.80%. The coating was tested again after three months of storage, and the weight loss was 0.80%. The coating was tested again after six months of storage, and the weight loss was 0.81%. An aluminum plant applied this coating in a small, side-inserted, self-baking anode aluminum electrolysis system operating at less than 60 kA. The current efficiency of the electrolytic aluminum was 87.7%, showing no significant change.

[0051] The components and contents of the coatings of more embodiments of the present invention are shown in Table 1.

[0052] Table 1 Content of each component of the coating in the embodiment

[0053]

[0054]

[0055] The components and contents of water glass in more embodiments of the present invention are shown in Table 2.

[0056] Table 2 Content of each component of water glass

[0057]

[0058] The preparation steps of the anti-oxidation and anti-corrosion coatings of Examples 4-8 and Comparative Examples 4-8 refer to Example 1, and the conditions of coating the anti-oxidation and anti-corrosion coatings on the surface of the carbon anode for sintering, high-temperature calcination in a tubular furnace, and subsequent performance testing are all repeated in Example 1.

[0059] For more test data, see Table 3.

[0060] Table 3 Test results

[0061]

Claims

1. An anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode, characterized in that: The composition includes the following components by mass percentage: main component 30.7%-38%, secondary component 17%-22%, binder 10.9%-14%, anti-corrosion additive 17%-25%, and the balance is water; the anti-corrosion additive with a content of 17%-25% is composed of the following raw materials in the following mass ratio: anti-corrosion additive 1 content 8%-13%, anti-corrosion additive 2 content 4%-13%, and anti-corrosion additive 3 content 5%-10%; The main components are white corundum powder, red corundum powder and microcrystalline corundum powder; The subcomponents include subcomponent 1 and subcomponent 2, subcomponent 1 includes phlogopite, biotite and sodium mica; subcomponent 2 includes potassium feldspar, sodium feldspar and calcium feldspar; The binder is sodium water glass and potassium water glass; Anti-corrosion additive 1 includes one or more of fluorinated graphite, fluorinated carbon black, fluorinated carbon fiber, and fluorinated graphene; anti-corrosion additive 2 includes one or more of methyl trifluoroacrylate, perfluoromethyl acrylate, ethyl trifluoroacrylate, and perfluoroethyl acrylate; anti-corrosion additive 3 includes one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF).

2. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 1, characterized in that: The main component is composed of the following raw materials in the following mass ratios: 40% to 60% white corundum powder, 30% to 40% red corundum powder, and 10% to 22% microcrystalline corundum powder.

3. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 2, characterized in that: The main component is composed of the following raw materials in the following mass ratios: 42% to 56% white corundum powder, 32% to 38% red corundum powder, and 12% to 20% microcrystalline corundum powder.

4. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 2, characterized in that: The white corundum powder has an Al2O3 content of 95% to 99%, a Na2O content of 0.01% to 0.05%, and a particle size between 180 mesh and 300 mesh; the red corundum powder has an Al2O3 content of 90% to 95%, a Cr2O3 content of 1% to 3%, and a particle size between 100 mesh and 200 mesh; the microcrystalline corundum powder has an Al2O3 content of 91% to 94%, a TiO2 content of 0.5% to 2%, and a particle size between 200 mesh and 300 mesh.

5. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 1, characterized in that: The subcomponent is composed of the following raw materials in the following mass ratios: phlogopite 7%-19%, biotite 12%-20%, sodium mica 14%-25%, potassium feldspar 14%-28%, sodium feldspar 8%-26%, and calcium feldspar 13%-30%.

6. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 5, characterized in that: The subcomponent is composed of the following raw materials in the following mass ratios: 11% to 18% phlogopite, 12% to 18% biotite, 16% to 25% sodium mica, 21% to 28% potassium feldspar, 21% to 26% sodium feldspar and 13% to 18% anorthite.

7. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 1, characterized in that: The binder is composed of the following raw materials in the following mass ratio: 67% to 80% of sodium water glass and 20% to 33% of potassium water glass.

8. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 7, characterized in that: The binder is composed of the following raw materials in the following mass ratio: 72% to 78% of sodium water glass and 22% to 28% of potassium water glass.

9. The anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 7, characterized in that: The Na2O content of sodium water glass is 4%~10%, the SiO2 content is 15%~44%, and the balance is deionized water; the K2O content of potassium water glass is 3%~10%, the SiO2 content is 15%~45%, and the balance is deionized water.

10. The method for preparing an anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to any one of claims 1 to 9, characterized in that: The specific steps are as follows: first weigh the raw materials of each component, mix the main component with the secondary component to obtain mixture A, mix the binder and the anti-corrosion additive to obtain mixture B, then pour mixture A, mixture B and water into a stirring tank in sequence, and stir thoroughly to obtain an anti-oxidation and anti-corrosion coating.

11. The method for preparing an anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 10, characterized in that: The preparation of mixture A is as follows: white corundum powder, red corundum powder, microcrystalline corundum powder, phlogopite, biotite, sodium mica, potassium feldspar, sodium feldspar, and calcium feldspar are sequentially put into a powder machine, and the machine is started for 2 to 6 hours to obtain mixture A; The preparation of mixture B is specifically as follows: sodium water glass, potassium water glass, anticorrosive additives and an appropriate amount of water are sequentially put into a magnetic stirrer, stirred at a temperature of 20-60°C and a stirring speed of 200-600 rpm for 1-5 hours to obtain mixture B.

12. The method for preparing an anti-oxidation and anti-corrosion coating for aluminum electrolytic carbon anode according to claim 11, characterized in that: During the preparation of mixture B, the stirring temperature is 30~80℃.

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