Inorganic prebaked anode steel claw coating and preparation method and application thereof

Abstract

The application discloses a pre-baked anode steel claw coating formula and a preparation method and application thereof. The pre-baked anode steel claw coating can be used for forming a protective coating on a surface layer of a steel claw and comprises 5-50 parts of a composite binder, 0.1-5 parts of a composite slow-release passivator and a solvent; the composite slow-release passivator comprises a phosphate and an inhibitor; and the composite binder comprises sol, water glass and a boron-containing compound. The preparation method comprises the following steps: (1) crushing raw materials; and (2) grinding and mixing the raw materials and the solvent according to proportions. The pre-baked anode steel claw coating adopts a comprehensive protection mode combining chemical passivation and structural strengthening, so that the coating has the advantages of high strength, high hardness, strong impact resistance, good resistance and strong anti-permeability, and the sustainability of the coating to the base material is ensured; the preparation method is simple, raw materials are easy to obtain, and the method is suitable for large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrolytic anode material, in particular to a prebaked anode steel claw coating and a preparation method and application thereof. BACKGROUND

[0002] The prebaked anode steel claw is an important component in the production of electrolytic aluminum, which connects the anode carbon block and the aluminum guide rod, bears the weight of the anode, and also transmits the super-capacity current. At a high temperature of 400-900 DEG C, the anode steel claw is easily subjected to baking, erosion, impact of electrolyte, anode covering material, air and electrolytic flue gas, and at the same time, it also bears the damage of periodic cycle of heat treatment, thermal deformation stress, electromagnetic force and impact force, which easily leads to corrosion, wear and shedding of the surface of the steel claw, causing serious damage to the steel claw and destruction of the cross-sectional uniformity, affecting the uniformity of the electrolytic cell, and further reducing the production efficiency of aluminum electrolysis, and significantly increasing the operating cost of electrolytic aluminum, while the consumption of anode steel claw is an important economic and technical index of aluminum electrolysis production. According to statistics, for example, for an enterprise with an annual output of 200,000 tons of primary aluminum, when the steel claw is severely corroded, the average service life of the anode steel claw is about 16 cycles, and the annual replacement and repair cost is as high as 8 million yuan, and the cost increase caused by the imbalance of the uniformity of the electrolytic cell is significantly higher than the data, and the corrosion products formed after the corrosion of the steel claw will enter the electrolyte, affecting the quality of the primary aluminum, the distribution of the current and the correct judgment of the operating conditions of the electrolytic cell.

[0003] In the process of aluminum electrolysis production, in order to prevent the anode steel claw from being washed and corroded by the electrolyte, protective measures need to be taken for the anode steel claw, but the corrosion resistance, oxidation resistance and delamination resistance of the anode steel claw have always been a difficult problem faced by the aluminum electrolysis industry, and how to reduce the corrosion, oxidation and washing of the anode steel claw is of great significance to prolong the service life of the steel claw, improve the quality of the primary aluminum and reduce the production cost. In the prior art, coating method is a common technical means for protecting the steel claw.

[0004] The current common surface treatment technology for prebaked anode steel claw mainly has two technical directions, one of which adopts substrate passivation technology, and the other of which adopts alloying technology mechanism to form a corrosion-resistant layer on the surface of the steel claw; the other one adopts the technical idea of increasing the maintenance structure on the outer layer of the anode steel claw, such as high-temperature resistant coating, to directly protect the anode steel claw and prevent various forms of corrosion.

[0005] As patent documents 202311639160.6, 202310080536.8, 202210835478.0, 201710842416.1 all use the above method, although these existing coatings and coatings have played a protective role for the anode steel claw to a certain extent, but there are still long process flow, poor impact resistance of the corrosion protection layer, easy to fail in the cyclic temperature difference use environment, easy to fall off in the continuous high temperature and strong corrosion condition, poor resistance and other single effect problems. SUMMARY

[0006] The present application provides a kind of prebaked anode steel claw paint and its preparation method and application, to solve the current existing steel claw coating due to single or unbalanced performance causes poor corrosion resistance, resistance, surface failure effect under extreme use environment difference technical problem.

[0007] To solve the above technical problems and achieve technical effects, the present application adopts the following technical solutions:

[0008] A kind of prebaked anode steel claw paint, including the following mass parts of components:

[0009] 5~50 portions of composite binder, 0.1~5 portions of composite slow-release passivation agent and solvent;

[0010] The composite slow-release passivation agent includes phosphate and corrosion inhibitor, the phosphate includes one or two of zirconium-based phosphate, aluminum-based phosphate, magnesium-based phosphate, calcium-based phosphate, chromium-based phosphate and sodium-based phosphate;The corrosion inhibitor includes the combination of at least two of chromate, nitrate, nitrite, borate, tungstate, benzoic acid, zinc sulfate and acid calcium carbonate;

[0011] The composite binder includes sol, water glass and boron-containing compound.

[0012] The design idea of the above technical solution is that, by composite binder and composite slow-release passivation agent, physical and chemical double protection is provided respectively, on the one hand, composite slow-release passivation agent is selected to provide chemical protection for anode in oxidation and adsorption aspects, on the other hand, the surface precipitation film formed by composite binder provides physical protection for anode, at the same time, composite slow-release passivation agent and composite binder form a protection system of three-dimensional interweaving, multi-phase inlay and gradient distribution, which not only ensures the continuous and stable performance of each function, but also promotes the structural strength, compactness, spreading effect, mechanical properties and slow-release effect of the coating, provides continuous and effective physical and chemical protection for the anode steel claw, achieves the purpose of preventing the steel claw from being eroded, maintaining the good working state of the steel claw and prolonging the service life of the steel claw, and finally maintains the uniform electrical balance of the anode, improves the performance index of the electrolytic cell, and significantly reduces the overhaul cost of the steel claw.

[0013] In the design of the composite slow-release passivation agent, the phosphate and the corrosion inhibitor form a composite passivation system, which utilizes the characteristic that the phosphate gradually decomposes at high temperature, and by adjusting the release rate of the passivation factor generated by the corrosion inhibitor, a sustained passivation effect on the surface of the steel claw is achieved. In the design of the composite binder, the water glass in the composite binder does not directly melt under the temperature conditions of the electrolytic cell, but first changes to a colloidal state, and is compounded with the boron-containing compound to form a molten body at different temperatures, which fills the voids generated by the decomposition of the base material and the coating, improves the sealing and stability of the coating material, and then improves the overall impact resistance and shear resistance of the coating after combining with other structural materials in the coating at high temperature, making the solidification bonding between the coating and the base material more dense and stable, showing good mechanical strength and excellent acid resistance. The basic adhesion, film forming stability of the sol material, and the compatibility and high temperature reaction of the boron-containing compound, water glass and other material components in the formula are good, and the boron-containing compound, water glass together reduces the technical problems of poor coating resistance and easy peeling under the condition of continuous high temperature and strong corrosion.

[0014] As a further preferred embodiment of the above technical solution, the mass ratio of the phosphate and the corrosion inhibitor is 1: (1-2.5).

[0015] As a further preferred embodiment of the above technical solution, the sol includes at least one of an aluminum sol or an aluminum-silicon sol; the water glass includes at least one of lithium water glass and potassium water glass; and the boron-containing compound is one or two of boron oxide, boron nitride, titanium boride, borax, chromium boride, calcium boride, and boric acid.

[0016] As a further preferred embodiment of the above technical solution, the prebaked anode steel claw coating further includes 5-30 parts by mass of a structural reinforcing agent, the structural reinforcing agent includes a skeleton material and kaolin; the skeleton material includes at least one of barite, glass powder, silicon powder, and mica powder; and the mass fraction of the kaolin in the structural reinforcing agent is 5%-50%. The filling powder such as barite and glass powder has stable chemical properties, especially in the hydrogen fluoride working environment of the electrolytic cell, so it can increase the thickness, strength and durability of the coating, and can be partially converted into a cosolvent and plugged in the gaps caused by the reaction or volatilization of other materials in the coating under high temperature and acidic conditions; at the same time, the filling powder with a considerable specific surface area has good wrapping effect on other materials under the combined action of the plasticity, bonding and viscosity of kaolin (thickening, dispersion, structural reinforcement), which reduces the loss of the coating under high temperature, high cavitation and high impact environment, and ensures the mechanical properties of the coating and the bonding effect with the base material. The structural reinforcing agent can participate in the construction of the protection system of the composite slow-release passivation agent and the composite binder mentioned above, and jointly reconstruct the multi-phase inlay, gradient distribution and composite phase toughening protection coating.

[0017] As a further preferred embodiment of the above technical solution, the total loss on ignition of the prebaked anode steel claw coating is ≤10%, and the total organic component mass is ≤5%. The volatilization of solvents during the film formation of the coating at a high temperature causes defects such as micropores and pinholes in the coating, which significantly affects the corrosion resistance of the coating; the leaching of coating components caused by acid gas corrosion also causes the formation of pores, thereby accelerating the damage of the coating and the corrosion of the metal substrate; in addition, considering the high-temperature environment of the electrolytic cell, the volatilization of organic components and the generation of VOCs during use will affect safety and the environment. Therefore, the present application uses an inorganic material coating system to reduce the above-mentioned problems.

[0018] Based on the same technical concept, the present application also provides a preparation method of the prebaked anode steel claw coating, comprising the following steps:

[0019] (1) crushing the passivator, the boron-containing compound, and the structure enhancer of the prebaked anode steel claw coating separately or in mixture;

[0020] (2) mixing the dissociated raw materials with other raw materials in proportion and adding a part of solvent for wet grinding, and then adding the remaining solvent for mixing to obtain the prebaked anode steel claw coating.

[0021] As a further preferred embodiment of the above technical solution, the particle size of the raw materials after dissociation in step (1) is controlled to be <150 um.

[0022] As a further preferred embodiment of the above technical solution, the particle size of the raw materials after grinding in step (2) is controlled to be <45 um.

[0023] As a further preferred embodiment of the above technical solution, in step (2), the stirring speed of the mixing operation is 200-500 rpm, and the mixing time is 15-60 min.

[0024] Based on the same technical concept, the present application also provides an application of the prebaked anode steel claw coating, which is used to form a protective coating on the surface of a prebaked anode steel claw used in an electrolytic aluminum process.

[0025] As a further preferred embodiment of the above technical solution, the application of the prebaked anode steel claw coating specifically comprises the following steps:

[0026] (1) uniformly coating the prebaked anode steel claw coating on the surface of the prebaked anode steel claw in the form of spraying or brushing;

[0027] (2) drying and curing the steel claw coated with the coating to obtain an anode steel claw coated with a protective coating.

[0028] As a further preferred solution of the above technical solution, the prebaked anode steel claw paint is uniformly coated on the surface of the prebaked anode steel claw, and the surface of the anode steel claw is sandblasted pretreated to make the surface meet the derusting level of Sa2.5 level.

[0029] As a further preferred solution of the above technical solution, the coating thickness in step (1) is greater than or equal to 100 μm.

[0030] As a further preferred solution of the above technical solution, the drying and curing treatment in step (2) is natural air drying curing or oven drying curing treatment, the natural air drying treatment time is more than 24 h; the oven drying curing treatment temperature is 35-60 ℃, and the oven drying time is more than 4 h.

[0031] Compared with the prior art, the present application has the following advantages:

[0032] (1) The prebaked anode steel claw paint of the present application adopts a multi-phase inlay, a step distribution, and a composite phase toughening and slow-release composite passivation coating system formula design path, uses a chemical passivation and physical protection combined paint protection system for the base material, reduces the decline of the comprehensive performance such as continuous anti-oxidation, impact resistance, and corrosion resistance of the coating in a high temperature environment, and can meet the protection requirements of the steel claw in a high dust, high temperature, high thermal shock, high air erosion, and high impact environment of the electrolytic cell.

[0033] (2) The prebaked anode steel claw paint preparation method of the present application is simple, the raw materials are easy to obtain, and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0034] The present application will be further described below in combination with specific embodiments.

[0035] Embodiment 1:

[0036] The prebaked anode steel claw paint of the present embodiment includes a composite binder, a composite slow-release passivation agent, an additive, and a solvent (water).

[0037] The composite slow-release passivation agent includes the following components by mass: 2 parts of sodium-based phosphate and aluminum-based phosphate (mass ratio of 1:1), 1.5 parts of chromate and nitrite (sodium chromate and sodium nitrite with a mass ratio of 1:1 are selected in the present embodiment).

[0038] The composite binder includes the following components by mass: 20 parts of aluminum sol, 15 parts of lithium water glass, and 8 parts of calcium boride.

[0039] The additive includes the following components by mass: 0.3 parts of calcium borate, 0.2 parts of a suspending agent, 0.5 parts of a dispersing agent, and 1 part of a thickening agent.

[0040] The prebaked anode steel claw paint preparation method of the present embodiment includes the following steps:

[0041] (1) Grinding each component to ensure that the particle size is ≤45 μm.

[0042] (2) Testing and screening the ground components to ensure that the quality meets the requirements.

[0043] (3) Feeding the raw materials of the composite binder and the composite sustained-release passivation agent into different mixers respectively to mix thoroughly.

[0044] (4) Adding the mixed raw materials of the composite sustained-release passivation agent into the raw materials of the composite binder to mix by stirring, and adding a solvent to stir at a speed of 300 rpm, and the mixing time is 30 min, thereby obtaining the prebaked anode steel claw coating of the present example.

[0045] The prebaked anode steel claw coating of the present example is used to form a protective coating on the surface of a prebaked anode steel claw used in an aluminum electrolysis process, and the specific method comprises the following steps:

[0046] (1) Preparing the surface of the anode steel claw by sandblasting to make the surface meet the Sa2.5 level of rust removal grade. The Sa2.5 rust removal grade standard is: completely spraying abrasive, completely removing rust and oxide scale, and the steel surface is nearly white after removing dust, and only has a small spot.

[0047] (2) Coating the prebaked anode steel claw coating to the surface of the prebaked anode steel claw in a standard method by spraying (the coating thickness is 120 μm).

[0048] (3) Naturally air-drying and curing the steel claw coated with the coating, and the natural air-drying and curing time is 48 h, thereby obtaining the anode steel claw coated with a protective coating.

[0049] The anode steel claw coated with a protective coating is tested, and the test method and results are shown as follows:

[0050] The test method refers to the standard: GB / T 21776-2008 “Guidelines for the Testing of Powder Coatings and Their Coatings” to test the adhesion, compressive strength and corrosion resistance of the coating, and the results are shown in Table 1.

[0051] Example 2:

[0052] The prebaked anode steel claw coating of the present example comprises a composite binder, a composite sustained-release passivation agent, a structure strengthening agent, an additive and a solvent (water).

[0053] The composite sustained-release passivation agent comprises the following components by mass: 2 parts of sodium-based phosphate and aluminum-based phosphate (mass ratio of 1:1), 1.5 parts of chromate and nitrite (sodium chromate and sodium nitrite with a mass ratio of 1:1 are selected in the present example).

[0054] The composite binder comprises the following components by mass: 20 parts of aluminum sol, 15 parts of lithium water glass, and 8 parts of calcium boride.

[0055] The structure reinforcing agent comprises the following components by mass: 25.5 parts of framework material and 4.5 parts of kaolin, and the framework material comprises barite, silicon powder, mica powder, and glass powder (mass ratio of 1:1:1:1).

[0056] The auxiliary agent comprises the following components by mass: 0.5 parts of calcium borate, 0.3 parts of suspending agent, 1 part of dispersing agent, and 1.5 parts of thickening agent.

[0057] The preparation method of the prebaked anode steel claw coating of the embodiment comprises the following steps:

[0058] (1) Each component is ground to ensure that the particle size is ≤45 μm.

[0059] (2) Each component after grinding is detected and selected to ensure that the quality meets the requirements.

[0060] (3) The raw materials of the composite binder and the composite slow-release passivation agent are respectively sent into different mixers for sufficient mixing.

[0061] (4) The raw materials of the composite slow-release passivation agent after uniform mixing are added to the raw materials of the composite binder for stirring and mixing, and a solvent is added for stirring at a speed of 300 rpm, and the mixing time is 30 min, thereby obtaining the prebaked anode steel claw coating of the embodiment.

[0062] The prebaked anode steel claw coating of the embodiment is used to form a protective coating on the surface of a prebaked anode steel claw used in an aluminum electrolysis process, and the specific method comprises the following steps:

[0063] (1) The surface of the anode steel claw is sandblasted for pretreatment, so that the surface meets the derusting level of Sa2.5 grade. The Sa2.5 derusting level standard is: completely spray the abrasive, completely remove the rust and oxide scale, and the steel surface is nearly white after removing the dust, and only has a small spot.

[0064] (2) The prebaked anode steel claw coating is coated onto the surface of the prebaked anode steel claw in a standard method by spraying (the coating thickness is 120 μm).

[0065] (3) The steel claw coated with the coating is naturally air-dried and cured, and the natural air-drying and curing time is 48 h, thereby obtaining the anode steel claw coated with the protective coating.

[0066] The anode steel claw coated with the protective coating is tested, and the test method and results are as follows:

[0067] The test method refers to the standard: GB / T 21776-2008 "Guidelines for the testing standards of powder coatings and their coatings" to test the adhesion, compressive strength and corrosion resistance of the coating, and the results are shown in Table 1.

[0068] To explore the influence of the change of kaolin content in the structure enhancer on the performance of the coating, while keeping other components and operations unchanged, the mass percentage of kaolin in the structure enhancer was adjusted in this embodiment, and the performance of the obtained coating was tested, and the results are shown in Table 2.

[0069] Example 3:

[0070] The prebaked anode steel claw coating of this embodiment includes a composite binder, a composite slow-release passivator, a structure enhancer, an auxiliary agent, and a solvent (water).

[0071] The composite slow-release passivator includes the following components by mass: 2 parts of sodium-based phosphate and aluminum-based phosphate (mass ratio 1:1), 2.5 parts of chromate and nitrite (sodium chromate and sodium nitrite with a mass ratio of 1:1 are selected in this embodiment).

[0072] The composite binder includes the following components by mass: 20 parts of aluminum sol, 15 parts of lithium water glass, and 8 parts of calcium boride.

[0073] The structure enhancer includes the following components by mass: 25.5 parts of skeleton material and 4.5 parts of kaolin, and the skeleton material includes barite, silicon powder, mica powder, and glass powder (mass ratio 1:1:1:1).

[0074] The auxiliary agent includes the following components by mass: 0.5 parts of calcium borate, 0.3 parts of a suspending agent, 1 part of a dispersing agent, and 1.5 parts of a thickening agent.

[0075] The preparation method of the prebaked anode steel claw coating of this embodiment includes the following steps:

[0076] (1) Grind each component to ensure that the particle size is ≤45 μm.

[0077] (2) Test and select the ground components to ensure that the quality meets the requirements.

[0078] (3) Put the raw materials of the composite binder and the composite slow-release passivator into different mixers respectively and mix thoroughly.

[0079] (4) Add the mixed raw materials of the composite slow-release passivator to the raw materials of the composite binder and stir, and add the solvent to stir at a speed of 300 rpm, and the mixing time is 30 min, to obtain the prebaked anode steel claw coating of this embodiment.

[0080] The prebaked anode steel claw paint of the present embodiment is used to form a protective coating on the surface of the prebaked anode steel claw used in the aluminum electrolysis process, and the specific method comprises the following steps:

[0081] (1) The surface of the anode steel claw is sandblasted for pretreatment, so that the surface meets the Sa2.5 level of derusting grade. The Sa2.5 derusting grade standard is: completely spray the abrasive, completely remove the rust and oxide scale, and the steel surface is nearly white after removing the dust, and only has a small spot.

[0082] (2) The prebaked anode steel claw paint is coated on the surface of the prebaked anode steel claw in a standard method by spraying (the coating thickness is 120 μm).

[0083] (3) The steel claw coated with the paint is naturally air-dried and cured for 48 h, and the anode steel claw coated with the protective coating is obtained.

[0084] The anode steel claw coated with the protective coating is tested, and the test method and results are as follows:

[0085] The test method refers to the standard: GB / T 21776-2008 "Guidelines for Testing Standards of Powder Coatings and Coatings" to test the adhesion, compressive strength and corrosion resistance of the coating, and the results are shown in Table 1.

[0086] Example 4:

[0087] The prebaked anode steel claw paint of the present embodiment comprises a composite binder, a composite slow-release passivator, a structure enhancer, an additive and a solvent (water).

[0088] The composite slow-release passivator comprises the following components by mass: 2 parts of sodium-based phosphate and aluminum-based phosphate (mass ratio 1:1), 2.5 parts of chromate and nitrite (sodium chromate and sodium nitrite with a mass ratio of 1:1 are selected in the present embodiment).

[0089] The composite binder comprises the following components by mass: 30 parts of aluminum sol, 15 parts of lithium water glass and 5 parts of calcium boride.

[0090] The structure enhancer comprises the following components by mass: 25.5 parts of skeleton material and 4.5 parts of kaolin, and the skeleton material comprises barite, silicon powder, mica powder and glass powder (mass ratio 1:1:1:1).

[0091] The additive comprises the following components by mass: 0.5 parts of calcium borate, 0.3 parts of suspending agent, 1 part of dispersing agent and 1.5 parts of thickening agent.

[0092] The preparation method of the prebaked anode steel claw paint of the present embodiment comprises the following steps:

[0093] (1) Grinding each component to ensure that the particle size is ≤45 μm.

[0094] (2) Testing and screening the ground components to ensure that the quality meets the requirements.

[0095] (3) Feeding the raw materials of the composite binder and the composite sustained-release passivation agent into different mixers respectively to mix thoroughly.

[0096] (4) Adding the mixed raw materials of the composite sustained-release passivation agent into the raw materials of the composite binder to mix by stirring, and adding a solvent to stir at a speed of 300 rpm, and the mixing time is 30 min, thereby obtaining the prebaked anode steel claw coating of the present example.

[0097] The prebaked anode steel claw coating of the present example is used to form a protective coating on the surface of a prebaked anode steel claw used in an aluminum electrolysis process, and the specific method comprises the following steps:

[0098] (1) Preparing the surface of the anode steel claw by sandblasting to make the surface meet the Sa2.5 level of rust removal grade. The Sa2.5 rust removal grade standard is: completely spraying abrasive, completely removing rust and oxide scale, and the steel surface is nearly white after removing dust, and only has a small spot.

[0099] (2) Coating the prebaked anode steel claw coating to the surface of the prebaked anode steel claw in a standard method by spraying (the coating thickness is 120 μm).

[0100] (3) Naturally air-drying and curing the steel claw coated with the coating, and the natural air-drying and curing time is 48 h, thereby obtaining the anode steel claw coated with a protective coating.

[0101] The anode steel claw coated with a protective coating is tested, and the test method and results are shown as follows:

[0102] The test method refers to the standard: GB / T 21776-2008 “Guidelines for the Testing Standards of Powder Coatings and Their Coatings”, and the adhesion, compressive strength and corrosion resistance of the coating are tested, and the results are shown in Table 1.

[0103] Comparative Example 1:

[0104] The prebaked anode steel claw coating of the present comparative example comprises a binder, a composite sustained-release passivation agent, an additive and a solvent (water).

[0105] The composite sustained-release passivation agent comprises the following components by mass: 2 parts of sodium-based phosphate and aluminum-based phosphate (mass ratio of 1:1), 1.5 parts of chromate and nitrite (sodium chromate and sodium nitrite with a mass ratio of 1:1 are selected in the present comparative example).

[0106] The binder comprises 47 parts by mass of aluminum sol.

[0107] The adjuvant includes the following components by mass: 0.5 parts of calcium borate, 0.3 parts of a suspending agent, 1 part of a dispersing agent, and 1.5 parts of a thickening agent.

[0108] The prebaked anode steel claw coating of the present comparative example was prepared in the same manner as Example 1.

[0109] The prebaked anode steel claw coating of the present example was used to form a protective coating on the surface of a prebaked anode steel claw used in an aluminum electrolysis process, and the specific method included the following steps:

[0110] (1) The surface of the anode steel claw was sandblasted for pretreatment, so that the surface met the Sa2.5 level of the derusting grade. The Sa2.5 derusting grade standard: completely spray the abrasive, completely remove the rust and oxide scale, and after removing the dust, the steel surface is nearly white metal luster with only a small spot.

[0111] (2) The prebaked anode steel claw coating was applied to the surface of the prebaked anode steel claw in the standard method by spraying (the coating thickness was 120 μm).

[0112] (3) The steel claw coated with the coating was naturally air-dried and cured for 48 h, and the anode steel claw coated with the protective coating was obtained.

[0113] The anode steel claw coated with the protective coating was tested, and the test method and results are shown below:

[0114] The test method referred to the standard: GB / T 21776-2008 "Guidelines for the Testing of Powder Coatings and Their Coatings" to test the adhesion, compressive strength, and corrosion resistance of the coating, and the results are shown in Table 1.

[0115] Comparative Example 2:

[0116] The prebaked anode steel claw coating of the present comparative example included a composite binder, a passivator, an adjuvant, and a solvent (water).

[0117] The passivator included 3.5 parts by mass of sodium-based phosphate.

[0118] The composite binder included the following components by mass: 20 parts of aluminum sol, 15 parts of lithium water glass, and 8 parts of calcium boride.

[0119] The adjuvant included the following components by mass: 0.5 parts of calcium borate, 0.3 parts of a suspending agent, 1 part of a dispersing agent, and 1.5 parts of a thickening agent.

[0120] The prebaked anode steel claw coating of the present comparative example was prepared in the same manner as Example 1.

[0121] The prebaked anode steel claw paint of the present embodiment is used to form a protective coating on the surface of a prebaked anode steel claw used in an aluminum electrolysis process, and the specific method comprises the following steps:

[0122] (1) The surface of the anode steel claw is sandblasted for pretreatment, so that the surface meets the rust removal level of Sa2.5. The Sa2.5 rust removal level standard is: completely spray the abrasive, completely remove the rust and oxide scale, and after removing the dust, the steel surface is nearly white metal luster with only small spots.

[0123] (2) The prebaked anode steel claw paint is coated on the surface of the prebaked anode steel claw in a standard method by spraying (the coating thickness is 120 μm).

[0124] (3) The steel claw coated with the paint is naturally air-dried and cured for 48 h, and the anode steel claw coated with the protective coating is obtained.

[0125] The anode steel claw coated with the protective coating is tested, and the test method and results are shown as follows:

[0126] The test method refers to the standard GB / T 21776-2008 "Guidelines for the Testing of Powder Coatings and Their Coatings", and the adhesion, compressive strength and corrosion resistance of the coating are tested, and the results are shown in Table 1.

[0127] Table 1: Coating performance test results of each embodiment and comparative example

[0128]

[0129] Table 2: Coating performance test results of different kaolin mass ratios of Example 2

[0130]

[0131] The above only describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above embodiments. Improvements and changes obtained by those skilled in the art without departing from the technical concept of the present application should also be considered as the protection scope of the present application.

Claims

1. A prebaked anode steel claw coating, characterized in that, The components include the following parts by weight: 5-50 parts composite adhesive, 0.1-5 parts composite slow-release passivating agent and solvent; The composite slow-release passivating agent comprises a phosphate and a corrosion inhibitor. The phosphate comprises one or two of zirconium phosphate, aluminum phosphate, magnesium phosphate, calcium phosphate, chromium phosphate, and sodium phosphate. The corrosion inhibitor comprises a combination of at least two of chromates, nitrates, nitrites, borates, tungstates, benzoic acid, zinc sulfate, and calcium carbonate. The composite binder comprises a sol, water glass, and a boron-containing compound; the sol comprises at least one of aluminum sol or aluminum-silicon sol; the water glass comprises at least one of lithium water glass and potassium water glass; and the boron-containing compound is one or two of boron oxide, boron nitride, titanium boride, borax, chromium boride, calcium boride, and boric acid.

2. The prebaked anode steel claw coating according to claim 1, characterized in that, The mass ratio of the phosphate to the corrosion inhibitor is 1:(1~2.5).

3. The prebaked anode steel claw coating according to claim 1, characterized in that, The mass ratio of water glass, boron-containing compound and sol in the composite binder is (5~50):(0.1~5):(5~20).

4. The prebaked anode steel claw coating according to claim 1, characterized in that, It also includes 5 to 30 parts by mass of a structural reinforcing agent, wherein the structural reinforcing agent comprises a skeleton material and kaolin; the skeleton material comprises at least one of barite, glass micro powder, silica micro powder and mica powder; and the kaolin accounts for 5% to 50% by mass of the structural reinforcing agent.

5. The prebaked anode steel claw coating according to any one of claims 1-4, characterized in that, It also includes 0.1 to 6 parts by weight of additives, said additives including at least one of calcium borate, suspending agent, dispersant and thickener.

6. The prebaked anode steel claw coating according to any one of claims 1-4, characterized in that, The total loss on ignition of the prebaked anode steel claw coating is ≤10%, and the total organic matter content is ≤5% by mass.

7. A method for preparing the prebaked anode steel claw coating according to claim 4, characterized in that, Includes the following steps: (1) The composite slow-release passivating agent, boron-containing compound, and structural reinforcing agent of the prebaked anode steel claw coating are crushed individually or in combination, and the particle size after crushing is controlled to be <150μm; (2) Mix the crushed raw materials with other raw materials in proportion and add a portion of solvent for wet grinding. After grinding, control the particle size to be <45μm. Add the remaining solvent and mix to obtain the prebaked anode steel claw coating.

8. The method for preparing the prebaked anode steel claw coating according to claim 7, characterized in that, In step (2), the stirring speed for adding the remaining solvent is 200~500 rpm and the mixing time is 15~60 min.

9. The application of a prebaked anode steel claw coating according to any one of claims 1-6 or a prebaked anode steel claw coating prepared by the preparation method according to any one of claims 7-8, characterized in that, The prebaked anode steel claw coating is used to form a protective coating on the surface of the prebaked anode steel claws used in the electrolytic aluminum process, and specifically includes the following steps: (1) Apply the coating material of the prebaked anode steel claw evenly to the surface of the prebaked anode steel claw by spraying or brushing; (2) The coated steel claw is dried and cured to obtain an anode steel claw coated with a protective coating.

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