Inorganic carbon mineralization coating and preparation method thereof

Abstract

The invention provides an inorganic carbon mineralization coating and a preparation method thereof.The inorganic carbon mineralization coating is used for being coated on the surface of a steel structure, and the inorganic carbon mineralization coating is prepared from, by weight, 100 parts of calcium silicate powder, 0.1-0.5 part of graphene oxide, 0.4-1 part of a water reducing agent, 0.1-0.3 part of a thickening agent and 1-3 parts of a dispersing agent, the mass percentage content of gamma-C2S phase in the calcium silicate powder is greater than or equal to 80%. The invention aims to provide the steel structure coating with good corrosion resistance and bonding strength.

Description

Technical Field

[0001] This invention relates to the field of metal anti-corrosion coating technology, specifically to an inorganic carbon mineralization coating and its preparation method. Background Technology

[0002] Steel structures are widely used in construction, bridges, and industrial facilities due to their high strength, lightweight, and good machinability. However, steel structures have poor corrosion resistance, especially in harsh environments such as humidity and salt spray, where corrosion easily occurs, affecting their service life and safety. Therefore, developing a coating that can effectively improve the corrosion resistance of steel structures is of significant practical importance.

[0003] However, existing coating anti-corrosion technologies have the following defects: (1) Traditional epoxy anti-corrosion coatings have poor salt spray resistance; (2) Traditional inorganic coatings (such as silicate and magnesium phosphate) have a bonding strength of only 3~6 MPa. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides an inorganic carbon mineralization coating and its preparation method, aiming to provide a steel structure coating with good corrosion resistance and bonding strength.

[0005] This application provides an inorganic carbon mineralization coating for coating on the surface of a steel structure. By weight, the raw materials of the inorganic carbon mineralization coating include 100 parts calcium silicate powder, 0.1 to 0.5 parts graphene oxide, 0.4 to 1 part water-reducing agent, 0.1 to 0.3 parts thickener, and 1 to 3 parts dispersant, wherein the mass percentage of the γ-C2S phase in the calcium silicate powder is greater than or equal to 80%.

[0006] Optionally, in some embodiments of this application, the graphene oxide includes at least one of monolayer graphene oxide, few-layer graphene oxide, and functional graphene oxide.

[0007] Optionally, in some embodiments of this application, the average particle size of the calcium silicate powder is 40~60μm.

[0008] Optionally, in some embodiments of this application, the raw material for the inorganic carbon mineralization coating further includes water, and the mass ratio of the calcium silicate powder to water is 100:20~25.

[0009] Optionally, in some embodiments of this application, the raw materials of the inorganic carbon mineralization coating further include a dispersing agent and a dispersing solvent. The dispersing agent includes one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyethylene glycol octylphenyl ether. The dispersing solvent is water. In the mixed system composed of the dispersing agent, the dispersing solvent, and the graphene oxide, the concentration of the graphene oxide is 8-12 mg / mL, and the concentration of the dispersing agent is 8-12 mg / mL.

[0010] Optionally, in some embodiments of this application, the thickener includes one or more of hydroxyethyl cellulose and hydroxypropyl methylcellulose ether.

[0011] Optionally, in some embodiments of this application, the dispersant includes one or more of sodium polystyrene, polyoxyethylene ether, polycarboxylate dispersant, and silane coupling agent.

[0012] Optionally, in some embodiments of this application, the water-reducing agent includes one or more of polycarboxylate water-reducing agents, aliphatic carboxylate water-reducing agents, and modified carboxylate water-reducing agents.

[0013] This application also proposes a method for preparing an inorganic carbon mineralization coating, which can be used to prepare the inorganic carbon mineralization coating described above. The preparation method includes the following steps: The dispersant is divided into a first dispersant and a second dispersant; Calcium silicate powder, water-reducing agent, thickener, first dispersant and water are mixed and stirred evenly to form a base mixture; A dispersion solution containing graphene oxide and a second dispersant are added to the base mixture and stirred until homogeneous to form a slurry. The slurry is applied to the surface of the steel structure to form a coating. The coating is cured in a carbon dioxide atmosphere to obtain an inorganic carbon mineralization coating.

[0014] Optionally, in some embodiments of this application, before the step of adding the graphene oxide-containing dispersion solution and the second dispersant to the base mixture and stirring evenly to form a slurry, the method further includes: mixing the graphene oxide, the dispersing aid, and the dispersing solvent to obtain a dispersion solution.

[0015] Optionally, in some embodiments of this application, in the step of curing the coating under a carbon dioxide atmosphere to obtain an inorganic carbon mineralization coating: The volume concentration of carbon dioxide in the carbon dioxide atmosphere is greater than or equal to 20%; The curing is carried out under a pressure of 0.05~0.1MPa for a duration of 0.5~24 h.

[0016] Optionally, in some embodiments of this application, in the step of adding a dispersion solution containing graphene oxide and a second dispersant to the base mixture and stirring evenly to form a slurry, the stirring speed is 300~600 r / min.

[0017] The inorganic carbon mineralization coating proposed in this application uses γ-C2S as the main material. The calcium carbonate generated by the carbonization reaction of γ-C2S can fill the pores and form a dense structure with small pores, which can give the coating better corrosion resistance and mechanical strength. By incorporating graphene oxide, which has excellent mechanical properties and chemical stability, it helps to further improve the density and further enhance the corrosion resistance and mechanical strength. At the same time, the silica gel generated during the carbonization reaction can also form chemical bonds with graphene oxide, enhance the adhesion of the coating, and improve the bonding strength and corrosion resistance of the coating on the steel structure.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Detailed Implementation

[0019] The following is a detailed description of the embodiments of the technical solution of this application. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the specification and claims of this application and the foregoing description are intended to cover non-exclusive inclusion.

[0021] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0022] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0025] In the description of the embodiments of this application, the term "at least one" refers to one or more, "more than one" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0026] This application provides an inorganic carbon mineralization coating for application onto the surface of a steel structure. By weight, the raw materials of the inorganic carbon mineralization coating include 100 parts calcium silicate powder, 0.1-0.5 parts graphene oxide, 0.4-1 parts water-reducing agent, 0.1-0.3 parts thickener, and 1-3 parts dispersant, wherein the mass percentage of the γ-C2S phase in the calcium silicate powder is greater than or equal to 80%.

[0027] It is understood that in the raw materials of the inorganic carbon mineralization coating, the mass ratio of calcium silicate powder, graphene oxide, water-reducing agent, thickener, and dispersant is 100:(0.1~0.5):(0.4~1):(0.1~0.3):(1~3). For example, the mass ratio of calcium silicate powder, graphene oxide, water-reducing agent, thickener, and dispersant can be 100:(0.1~0.15):(0.4~1):(0.1~0.3):(1~3), 100:(0.15~0.2):(0.4~1):(0.1~0.3):(1~3), 100:(0.2~0.3):(0.4~1):(0.1~0.3):(1~3), 100:(0.3~0.4):(0.4~1):(0.1~0.3):(1~3), 100:(0.4~0.5):(0.4~0.3 ... .5):(0.4~0.8):(0.1~0.3):(1~3), 100:(0.1~0.5):(0.6~1):(0.2~0.3):(1~3), 100:(0.1~0.5):(0.6~0.8):(0.15~0.25):(1~2), 100:(0.1~0.5):(0.4~1):(0.1~0.2):(2~3), 100:(0.5~0.8):(0.55~0.75):(0.15~0.25):(1.5~2.5), etc.

[0028] The inorganic carbon mineralization coating proposed in this application uses γ-C2S as the main material. The calcium carbonate generated through the carbonization reaction of γ-C2S fills the pores, forming a dense structure with small pores. This imparts excellent corrosion resistance and mechanical strength to the coating. The incorporation of graphene oxide, which possesses excellent mechanical properties and chemical stability, further enhances the density, corrosion resistance (or salt spray resistance), and mechanical strength. Simultaneously, the silica gel generated during the carbonization reaction can chemically bond with graphene oxide, strengthening the coating's adhesion and effectively blocking the penetration of corrosive agents, thus improving the coating's bonding strength and corrosion resistance on the steel structure. In summary, the inorganic carbon mineralization coating of this application exhibits high corrosion resistance and bonding strength, good compatibility with steel structures, and is less prone to cracking under thermal stress. Furthermore, the formulation of this application has a low content of volatile organic compounds, meeting environmental protection requirements and having minimal impact on air quality, thus possessing the advantages of being green and environmentally friendly.

[0029] In some embodiments of this application, the mass ratio of calcium silicate powder to graphene oxide can be 100:(0.1~0.5). Controlling this range helps to balance and improve the adhesion and density of the coating. When the proportion of graphene oxide is too small, the improvement in density and adhesion is limited. When the proportion is too large, there are problems such as increased cost, decreased uniformity of coating slurry, and decreased density and adhesion of coating.

[0030] In some embodiments of this application, calcium silicate powder with γ-C2S as the main phase is used as the main material. Calcium silicate powder does not readily react with water, eliminating the need for additional retarder during preparation and ensuring good dispersibility of the cementitious material and graphene. In this main material, the mass percentage of the γ-C2S phase is greater than or equal to 80 wt%, for example, it can be 80%, 85%, 90%, 95%, 99%, 100%, etc. Using calcium silicate powder with a high γ-C2S phase content allows for the formation of a dense structure through a carbonization reaction.

[0031] To better mix the reaction and reduce the amount of water added in order to construct a dense, high-strength structure, it is advisable to use calcium silicate powder with a smaller particle size. For example, in some preferred embodiments, the average particle size of the calcium silicate powder is 40~60 μm, such as 60 μm, 58 μm, 55 μm, 50 μm, 45 μm, 40 μm, etc.

[0032] In some embodiments of this application, the graphene oxide may include, but is not limited to, at least one of monolayer graphene oxide, few-layer graphene oxide, and functional graphene oxide.

[0033] In some embodiments of this application, the raw materials for the inorganic carbon mineralization coating also include water, and the mass ratio of the calcium silicate powder to water is 100:20~25; for example, it can be 100:20, 100:21, 100:22, 100:23, 100:24, 100:25 and any two of the above values.

[0034] To improve the uniformity of graphene oxide distribution in the coating and enhance its dispersion effect during the mixing stage, in some embodiments of this application, the raw materials of the inorganic carbon mineralization coating may further include a dispersing agent and a dispersing solvent. The dispersing agent may include, but is not limited to, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyethylene glycol octylphenyl ether; the dispersing solvent is water. In the mixed system composed of the dispersing agent, the dispersing solvent, and the graphene oxide, the concentration of the graphene oxide is 8-12 mg / mL, and the concentration of the dispersing agent is 8-12 mg / mL. It is understood that the actual amount of this mixed system is based on the proportion of graphene oxide in the coating slurry. Provided that the mass ratio of calcium silicate powder to graphene oxide in the coating slurry is 100:(0.1-0.5), the actual amount of the mixed system can be adjusted according to its concentration.

[0035] In some embodiments of this application, the thickener may include, but is not limited to, one or more of hydroxyethyl cellulose and hydroxypropyl methyl cellulose ether. These materials have good compatibility with other components and can effectively improve the flowability of the coating slurry.

[0036] In some embodiments of this application, the dispersant may include, but is not limited to, one or more of sodium polystyrene, polyoxyethylene ether, polycarboxylate dispersant, and silane coupling agent. These materials have good compatibility with other components and can effectively improve the dispersibility of the coating slurry, ensuring uniform dispersion of each component and allowing them to fully exert their respective functions.

[0037] In some embodiments of this application, the water-reducing agent may include, but is not limited to, one or more of polycarboxylate water-reducing agents, aliphatic carboxylate water-reducing agents, and modified carboxylate water-reducing agents. These materials have good compatibility with other components and can effectively improve the fluidity of the coating slurry, reducing water consumption. In some embodiments, the solid content of the water-reducing agent may be 30%.

[0038] Furthermore, this application also proposes a method for preparing an inorganic carbon mineralization coating. According to this method, the inorganic carbon mineralization coating described above can be obtained. The preparation method includes the following steps: S10, the dispersant is divided into a first dispersant and a second dispersant; S20: Mix calcium silicate powder, water-reducing agent, thickener, first dispersant and water, stir evenly to form a base mixture; S30, add the dispersion solution containing graphene oxide and the second dispersant to the base mixture, stir evenly to form a slurry; S40, the slurry is applied to the surface of the steel structure to form a coating; S50, under a carbon dioxide atmosphere, cures the coating to obtain an inorganic carbon mineralization coating.

[0039] In the preparation method of this application, the dispersant is first divided into two parts. One part is mixed with calcium silicate powder, water-reducing agent, thickener, and water to form a base mixture. Then, it is mixed with the remaining dispersant and a dispersion solution containing graphene oxide to form a slurry. This slurry is then coated on the surface of a steel structure and cured with CO2 to induce a carbonization reaction, thus obtaining an inorganic carbon mineralization coating. The preparation method is simple, easy to apply, and can produce a coating with both high corrosion resistance and high adhesion. This coating can effectively protect the steel structure from corrosion by humid and salt spray environments, and has good compatibility with the steel structure, making it less prone to cracking under thermal stress.

[0040] The specific types and amounts of calcium silicate powder, graphene oxide, water-reducing agent, thickener, and dispersant involved in the above steps are as described above and will not be repeated here.

[0041] In some embodiments of this application, in step S20, mechanical stirring is used for mixing, and the stirring speed can be 800~1500 r / min.

[0042] In some embodiments of this application, a step of preparing a dispersion solution is included before step S30. The preparation of the dispersion solution can be carried out by the following steps: mixing graphene oxide, a dispersing agent and a dispersing solvent to obtain a dispersion solution.

[0043] In some embodiments of this application, in step S30, mechanical stirring is used for mixing, and the stirring speed is 300~600 r / min.

[0044] In some embodiments of this application, in step S40, the coating method can be spraying, scraping, etc. In order to form a more uniform coating with better adhesion, the surface of the steel structure can be pretreated before coating, for example, removing rust and oil stains from the surface of the steel structure.

[0045] In step S50, carbon dioxide is used to cure the coating, which helps to improve the curing rate and effect, and can achieve higher strength in a shorter time, greatly shortening the time it takes for the coating to achieve sufficient strength.

[0046] To improve the maintenance effect, the pressure and time during maintenance can be optimized. For example, the maintenance can be carried out under a pressure environment of 0.05~0.1MPa, where the pressure can be 0.05MPa, 0.06MPa, 0.07MPa, 0.08MPa, 0.09MPa, 0.1MPa, or any two of the above values. Alternatively, the maintenance time can be controlled within the range of 0.5~24 hours, where the time can be 0.5 hours, 1 hour, 3 hours, 5 hours, 8 hours, 10 hours, 13 hours, 15 hours, 18 hours, 20 hours, 24 hours, or any two of the above values.

[0047] In step S50, the volume concentration of carbon dioxide in the carbon dioxide atmosphere is greater than or equal to 20% VOL; it can be understood that the concentration refers to the percentage of carbon dioxide volume in the atmosphere. Preferably, the volume concentration can be 30% VOL - 100% VOL.

[0048] Furthermore, the CO2 gas used in the carbon dioxide atmosphere is preferably sourced from CO2-rich industrial kiln exhaust gas, or preferably from high-concentration CO2 gas enriched from various industrial waste gases. This invention does not impose any special restrictions on the source of the CO2-rich industrial kiln exhaust gas; any industrial kiln exhaust gas obtained using methods well-known in the art will suffice. The enrichment process is also not particularly limited; any process well-known in the art that can produce CO2 gas within the aforementioned concentration range is acceptable. This invention significantly reduces carbon emissions and demonstrates outstanding environmental benefits by fully utilizing CO2-rich industrial kiln exhaust gas and high-concentration CO2 gas enriched from various industrial waste gases.

[0049] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0050] Example 1 In this embodiment, the steps for preparing the graphene-reinforced inorganic carbon mineralization coating are as follows: Samples were prepared according to the following raw material ratio: 100g calcium silicate powder, 10mL reduced graphene oxide dispersion (equivalent to 0.1g reduced graphene oxide), 0.4g polycarboxylate superplasticizer, 0.1g hydroxyethyl cellulose, 1g polycarboxylate dispersant, and 25g water. The average particle size of the calcium silicate powder was approximately 48.3 μm, and the mass percentage of the γ-C₂S phase in the calcium silicate powder was 83%. The reduced graphene oxide dispersion was a mixture of reduced graphene oxide (rGO), sodium dodecyl sulfate, and water, with both the reduced graphene oxide concentration and the sodium dodecyl sulfate concentration being 10mg / mL.

[0051] S1. Mix reduced graphene oxide, sodium dodecyl sulfate, and water to prepare a graphene dispersion solution.

[0052] S2. Divide the dispersant (polycarboxylate) into two parts. Mix one part of the polycarboxylate dispersant with calcium silicate powder, polycarboxylate superplasticizer, hydroxyethyl cellulose, polycarboxylate, and water. Stir evenly with a high-speed disperser to form a base mixture at a stirring speed of 1200 r / min.

[0053] S3. Add the graphene dispersion solution and another part of the polycarboxylate dispersant to the base mixture, stir evenly to form a coating slurry, and the stirring speed is 500 r / min; S4. The coating slurry is uniformly sprayed onto the surface of the steel structure to form a coating with a thickness of 300μm; S5. The coating is cured in a CO2 atmosphere (CO2 concentration of 100% VOL) ​​at a pressure of 0.1 MPa for 2 hours to obtain an inorganic carbon mineralization coating containing graphene.

[0054] Example 2 This embodiment is basically the same as Embodiment 1, except that the raw material ratio in this embodiment is: 100g calcium silicate powder, 20mL reduced graphene oxide dispersion (equivalent to 0.2g reduced graphene oxide), 0.5g polycarboxylate superplasticizer, 0.1g hydroxyethyl cellulose, 1g polycarboxylate, and 20g water. All other parameters and conditions remain unchanged.

[0055] Example 3 This embodiment is basically the same as Embodiment 1, except that the raw material ratio in this embodiment is: 100g calcium silicate powder, 30mL reduced graphene oxide dispersion (equivalent to 0.3g reduced graphene oxide), 0.6g polycarboxylate superplasticizer, 0.2g hydroxyethyl cellulose, 2g polycarboxylate, and 20g water. All other parameters and conditions remain unchanged.

[0056] Example 4 This embodiment is basically the same as Embodiment 1, except that the raw material ratio in this embodiment is: 100g calcium silicate powder, 40mL reduced graphene oxide dispersion (equivalent to 0.4g reduced graphene oxide), 0.7g polycarboxylate superplasticizer, 0.2g hydroxyethyl cellulose, 2g polycarboxylate, and 15g water. All other parameters and conditions remain unchanged.

[0057] Example 5 This embodiment is basically the same as Embodiment 1, except that the raw material ratio in this embodiment is: 100g calcium silicate powder, 50mL reduced graphene oxide dispersion (equivalent to 0.5g reduced graphene oxide), 0.6g polycarboxylate superplasticizer, 0.3g hydroxyethyl cellulose, 3g polycarboxylate, and 15g water. All other parameters and conditions remain unchanged.

[0058] Example 6 In this embodiment, the steps for preparing the graphene-reinforced inorganic carbon mineralization coating are as follows: Samples were prepared according to the following raw material ratio: 100g calcium silicate powder, 10mL monolayer graphene oxide dispersion (equivalent to 0.1g monolayer graphene oxide), 0.4g polycarboxylate superplasticizer, 0.1g hydroxypropyl methylcellulose ether, 1g polycarboxylate, and 25g water. The average particle size of the calcium silicate powder was approximately 48.3 μm, and the mass percentage of the γ-C₂S phase in the calcium silicate powder was 83%. The monolayer graphene oxide dispersion was a mixture of monolayer graphene oxide (rGO), sodium dodecyl sulfate, and water, with both the concentration of monolayer graphene oxide and sodium dodecyl sulfate being 10mg / mL.

[0059] S1. Mix monolayer graphene oxide, sodium dodecyl sulfate, and water to prepare a graphene dispersion solution.

[0060] S2. Divide the dispersant (polycarboxylate) into two parts. Mix one part of the polycarboxylate with calcium silicate powder, polycarboxylate superplasticizer, hydroxypropyl methylcellulose ether, polycarboxylate, and water. Stir the mixture evenly with a high-speed disperser to form a base mixture at a stirring speed of 800 r / min.

[0061] S3. Add the graphene dispersion solution and another part of polycarboxylate to the base mixture, stir evenly to form a coating slurry, and stir at a stirring rate of 500 r / min; S4. The coating slurry is uniformly sprayed onto the surface of the steel structure to form a coating with a thickness of 300μm; S5. The coating is cured in a CO2 atmosphere (CO2 concentration of 100% VOL) ​​at a pressure of 0.08 MPa for 2 hours to obtain an inorganic carbon mineralization coating containing graphene.

[0062] Example 7 In this embodiment, the steps for preparing the graphene-reinforced inorganic carbon mineralization coating are as follows: Samples were prepared according to the following raw material ratio: 100g calcium silicate powder, 10mL of few-layer graphene oxide dispersion (equivalent to 0.1g of few-layer graphene oxide), 0.4g aliphatic carboxylic acid water-reducing agent, 0.1g hydroxyethyl cellulose, 1g silane coupling agent, and 25g water. The average particle size of the calcium silicate powder was approximately 48.3 μm, and the mass percentage of the γ-C₂S phase in the calcium silicate powder was 83%. The few-layer graphene oxide dispersion was a mixture of few-layer graphene oxide (rGO), sodium dodecyl sulfate, and water, with both the concentration of few-layer graphene oxide and sodium dodecyl sulfate being 10mg / mL.

[0063] S1. Mix a few-layer graphene oxide, sodium dodecyl sulfate, and water to prepare a graphene dispersion solution.

[0064] S2. Divide the dispersant (silane coupling agent) into two parts. Mix one part of the silane coupling agent with calcium silicate powder, aliphatic carboxylic acid water-reducing agent, hydroxyethyl cellulose, silane coupling agent and water. Stir evenly with a high-speed disperser to form a base mixture at a stirring speed of 1500 r / min.

[0065] S3. Add the graphene dispersion solution and another part of the silane coupling agent to the base mixture, stir evenly to form a coating slurry, and stir at a stirring rate of 600 r / min; S4. The coating slurry is uniformly sprayed onto the surface of the steel structure to form a coating with a thickness of 300μm; S5. The coating is cured in a CO2 atmosphere (CO2 concentration of 100% VOL) ​​at a pressure of 0.1 MPa for 0.5 h to obtain an inorganic carbon mineralization coating containing graphene.

[0066] Example 8 In this embodiment, the steps for preparing the graphene-reinforced inorganic carbon mineralization coating are as follows: Samples were prepared according to the following raw material ratio: 100g calcium silicate powder, 10mL reduced graphene oxide dispersion (equivalent to 0.1g reduced graphene oxide), 0.4g modified carboxylic acid water-reducing agent, 0.1g hydroxyethyl cellulose, 1g sodium polystyrene, and 25g water. The average particle size of the calcium silicate powder was approximately 48.3 μm, and the mass percentage of the γ-C2S phase in the calcium silicate powder was 83%. The reduced graphene oxide dispersion was a mixture of reduced graphene oxide (rGO), polyethylene glycol octylphenyl ether, and water, with both the reduced graphene oxide concentration and the polyethylene glycol octylphenyl ether concentration being 10mg / mL.

[0067] S1. Reduced graphene oxide, polyethylene glycol octylphenyl ether, and water are mixed to prepare a graphene dispersion solution.

[0068] S2. Divide the dispersant (sodium polystyrene) into two parts. Mix one part of sodium polystyrene with calcium silicate powder, modified carboxylic acid water-reducing agent, hydroxyethyl cellulose, sodium polystyrene, and water. Stir evenly with a high-speed disperser to form a base mixture at a stirring speed of 1200 r / min.

[0069] S3. Add the graphene dispersion solution and another part of sodium polystyrene to the base mixture, stir evenly to form a coating slurry, and the stirring speed is 300 r / min; S4. The coating slurry is uniformly sprayed onto the surface of the steel structure to form a coating with a thickness of 300μm; S5. The coating is cured in a CO2 atmosphere (CO2 concentration of 100% VOL) ​​at a pressure of 0.05 MPa for 24 hours to obtain an inorganic carbon mineralization coating containing graphene.

[0070] Example 9 This embodiment is basically the same as Example 1, except that the mass of the reduced graphene oxide dispersion in this embodiment is 30 mL (equivalent to 0.3 g of reduced graphene oxide). All other parameters and conditions remain unchanged.

[0071] Example 10 This embodiment is basically the same as Example 1, except that the mass of the reduced graphene oxide dispersion in this embodiment is 50 mL (equivalent to 0.5 g of reduced graphene oxide). All other parameters and conditions remain unchanged.

[0072] Comparative Example 1 This comparative example is basically the same as Example 4, except that the raw materials in this comparative example do not contain reduced graphene oxide dispersion. Otherwise, all other parameters and conditions remain unchanged.

[0073] Comparative Example 2 This comparative example is essentially the same as Example 4, except that the raw materials in this comparative example do not contain polycarboxylate dispersant. Otherwise, all other parameters and conditions remain unchanged.

[0074] Comparative Example 3 This comparative example is essentially the same as Example 4, except that the raw materials in this comparative example do not contain hydroxyethyl cellulose thickener. Otherwise, all other parameters and conditions remain unchanged.

[0075] Comparative Example 4 This comparative example is basically the same as Example 4, except that the carbonization curing time in this comparative example is 12 hours. Otherwise, all other parameters and conditions remain unchanged.

[0076] Comparative Example 5 This comparative example is basically the same as Example 4, except that the pressure during curing is 0.1 MPa. Otherwise, all other parameters and conditions remain unchanged.

[0077] Comparative Example 6 This comparative example is basically the same as Example 4, except that the mass of the reduced graphene oxide dispersion in this comparative example is 70 mL (equivalent to 0.7 g of reduced graphene oxide). All other parameters and conditions remain unchanged.

[0078] Comparative Example 7 This comparative example is basically the same as Example 4, except that the mass percentage of the γ-C2S phase in the calcium silicate powder in this comparative example is 70%. All other parameters and conditions remain unchanged.

[0079] Comparative Example 8 This comparative example is basically the same as Example 4, except that the steel structure is replaced with a stone structure. All other parameters and conditions remain unchanged.

[0080] Comparative Example 9 This comparative example is basically the same as Example 4, except that the steel structure is replaced with a concrete structure. All other parameters and conditions remain unchanged.

[0081] Experimental example The performance of the inorganic carbon mineralization coatings prepared in each embodiment and comparative example was tested using the following methods: The state in the container represents the state of the coating slurry obtained in step S3; The bonding strength is obtained through an adhesion test, and the specific test method can be found in GB / T5210-2006. Salt spray resistance testing can be performed in accordance with GB / T10125; Temperature difference cracking rate detection: For each example or comparative example, 10 coatings were prepared as samples according to their respective methods; the coatings were alternately placed in 0℃ and 100℃ environments for 1 hour in each environment, alternating 10 times, and the occurrence of cracking was observed. The percentage of cracks in the 10 coatings was then calculated and recorded as the temperature difference cracking rate. The 0℃ and 100℃ environments were achieved by continuously supplying cold airflow and high-temperature steam to the coating surface.

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084] As can be seen from the table above: (1) The test data of each embodiment shows that the coatings prepared in each embodiment are free of hard lumps after stirring and are in a uniform state. This indicates that the mixture of the coatings is of uniform quality and there is no clumping phenomenon, which is suitable for construction. The bonding strength and salt spray resistance of the coatings in each embodiment are high. In particular, the bonding strength of embodiments 3 to 5 reached 9.0 to 9.5 MPa and the salt spray resistance exceeded 5000 hours. This shows that the inorganic carbon mineralization coating prepared by the preparation method provided by the present invention has high bonding strength and excellent corrosion resistance. It has good compatibility with steel structures and can well meet the requirements of steel structure corrosion protection, and has good quality.

[0085] (2) Comparing Examples 1 to 5, and Examples 1, 9, 10 and Comparative Example 6, it can be seen that controlling the ratio of calcium silicate powder to graphene in the range of 100:0.1 to 0.5 helps to balance and improve the adhesion and corrosion resistance of the coating. Within this range, as the proportion of graphene dispersion increases, the adhesion and corrosion resistance of the inorganic carbon mineralization coating tend to increase. However, when graphene is added in excess, it will affect the quality of the coating.

[0086] (3) Comparing the data of Example 4 with Comparative Examples 1-3 and Comparative Example 7, it can be seen that the technical solutions outside the proportion range provided by the present invention are difficult to achieve the performance that the examples can achieve. Comparative Examples 1-3 show that without the addition of graphene dispersion, thickener, and dispersant, the components in the coating are difficult to disperse evenly and connect tightly, resulting in an uneven coating structure and a significant reduction in adhesion and corrosion resistance. Comparative Example 7 shows that using calcium silicate powder with a low γ-C2S phase ratio is not conducive to improving the coating's adhesion, corrosion resistance, and compatibility.

[0087] (4) Comparing Example 4 and Comparative Examples 4-5, it can be seen that extending the curing time to 12 hours or increasing the carbonization pressure to 1 MPa did not significantly improve the coating performance. This indicates that after a carbonization pressure of 0.05 MPa and a carbonization curing time of 2 hours, the reaction inside the coating was basically completed, achieving optimal performance. Therefore, it can be seen that the present invention can obtain high strength in a short time using CO2 curing, greatly shortening the time for the coating to gain strength.

[0088] (5) Comparing Example 4 and Comparative Examples 8-9, it can be seen that the coating proposed in this invention has higher bonding strength and better salt spray resistance when applied to steel structures compared to stone or concrete materials, indicating that the coating proposed in this application has a better matching effect with steel.

[0089] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An inorganic carbon mineralization coating for application to the surface of a steel structure, characterized in that, The inorganic carbon mineralization coating comprises, by weight, 100 parts calcium silicate powder, 0.1 to 0.5 parts graphene oxide, 0.4 to 1 part water-reducing agent, 0.1 to 0.3 parts thickener and 1 to 3 parts dispersant, wherein the mass percentage of γ-C2S phase in the calcium silicate powder is greater than or equal to 80%.

2. The inorganic carbon mineralization coating according to claim 1, characterized in that, The graphene oxide includes at least one of monolayer graphene oxide, few-layer graphene oxide, and functional graphene oxide; and / or, The average particle size of the calcium silicate powder is 40 μm to 60 μm; and / or, The raw materials for the inorganic carbon mineralization coating also include water, and the mass ratio of calcium silicate powder to water is 100:20~25.

3. The inorganic carbon mineralization coating according to claim 1 or 2, characterized in that, The raw materials for the inorganic carbon mineralization coating also include a dispersing agent and a dispersing solvent. The dispersing agent includes one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyethylene glycol octylphenyl ether. The dispersing solvent is water. In the mixed system composed of the dispersing agent, the dispersing solvent, and the graphene oxide, the concentration of the graphene oxide is 8-12 mg / mL, and the concentration of the dispersing agent is 8-12 mg / mL.

4. The inorganic carbon mineralization coating according to claim 1, characterized in that, The thickener includes one or more of hydroxyethyl cellulose and hydroxypropyl methylcellulose ether.

5. The inorganic carbon mineralization coating according to claim 1, characterized in that, The dispersant includes one or more of sodium polystyrene, polyoxyethylene ether, polycarboxylate dispersant, and silane coupling agent.

6. The inorganic carbon mineralization coating according to claim 1, characterized in that, The water-reducing agent includes one or more of polycarboxylate water-reducing agents, aliphatic carboxylate water-reducing agents, and modified carboxylate water-reducing agents.

7. A method for preparing an inorganic carbon mineralization coating as described in any one of claims 1 to 6, characterized in that, The following steps are involved: The dispersant is divided into a first dispersant and a second dispersant; Calcium silicate powder, water-reducing agent, thickener, first dispersant and water are mixed and stirred evenly to form a base mixture; A dispersion solution containing graphene oxide and a second dispersant are added to the base mixture and stirred until homogeneous to form a slurry. The slurry is applied to the surface of the steel structure to form a coating. The coating is cured in a carbon dioxide atmosphere to obtain an inorganic carbon mineralization coating.

8. The method for preparing the inorganic carbon mineralization coating according to claim 7, characterized in that, Before the step of adding the graphene oxide dispersion and the second dispersant to the base mixture and stirring evenly to form a slurry, the method further includes: mixing the graphene oxide, the dispersing aid, and the dispersing solvent to obtain a dispersion solution.

9. The method for preparing the inorganic carbon mineralization coating according to claim 7, characterized in that, In the step of curing the coating under a carbon dioxide atmosphere to obtain an inorganic carbon mineralization coating: The volume concentration of carbon dioxide in the carbon dioxide atmosphere is greater than or equal to 20%; The curing is carried out under a pressure of 0.05~0.1MPa for a duration of 0.5~24 h.

10. The method for preparing the inorganic carbon mineralization coating according to claim 7, characterized in that, In the step of adding the graphene oxide dispersion and the second dispersant to the base mixture and stirring evenly to form a slurry, the stirring speed is 300~600 r / min.

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