A self-luminous geopolymer inorganic coating and preparation method thereof

Abstract

This application discloses a self-luminous geopolymer inorganic coating and its preparation method. The coating comprises, by weight, 100 parts of a silicon-aluminum-rich raw material, 50-90 parts of a liquid alkali activator, 60-100 parts of a fluorescent agent, 5-20 parts of a reflective agent, and 10-30 parts of a filler. The fluorescent agent comprises phosphor particles and a coating layer located on the surface of the phosphor particles, the coating layer being composed of metal ions and acid ions. The metal ions are selected from at least one of calcium ions and magnesium ions, and the acid ions are selected from either silicate or aluminate. The coating layer is made of a material with a similar group structure to the silicon-aluminum-rich raw material, ensuring that the coating's strength development and adhesion to concrete are not affected. The phosphor particles can also be stably present over a long period of time, thereby ensuring the long-term luminescence effect of the phosphor.

Description

Technical Field

[0001] The present application relates to the technical field of functional architectural coatings, and in particular to a self-luminous geopolymer inorganic coating and a preparation method thereof. Background Art

[0002] Self-luminous concrete incorporates long-lasting fluorescent powder into concrete, allowing it to absorb and store sunlight during the day, and then slowly release the energy stored in the fluorescent powder at night, continuously emitting light. However, if the existing concrete components are dismantled as a whole and replaced with self-luminous concrete, the investment cost is huge. Therefore, preparing self-luminous paint and coating the existing concrete components is a more effective and environmentally friendly construction method. Among them, inorganic self-luminous paint prepared with geopolymer as the matrix can play a role in resisting corrosion and inhibiting chemical ion erosion when applied to the concrete surface, which can further improve the durability of the components. However, directly adding fluorescent powder will affect the strength of geopolymers, etc., and because the fluorescent powder itself will also participate in alkaline hydrolysis and be consumed, it will affect the luminous performance of the paint. Summary of the Invention

[0003] In view of this, the present application provides a self-luminous geopolymer inorganic coating and a preparation method thereof, aiming to improve the strength and luminescence performance of the self-luminous inorganic coating based on geopolymer.

[0004] The embodiment of the present application is implemented as follows: a self-luminous geopolymer inorganic coating of the present application comprises, by weight: 100 parts of a silicon-aluminum-rich raw material, 50-90 parts of a liquid alkali activator, 60-100 parts of a fluorescent agent, 5-20 parts of a reflective agent and 10-30 parts of a filler;

[0005] The fluorescent agent includes fluorescent particles and a coating layer located on the surface of the fluorescent particles, wherein the coating layer is composed of metal ions and acid ions; wherein the metal ions are selected from at least one of calcium ions and magnesium ions; and the acid ions are selected from any one of silicate and aluminate.

[0006] In some embodiments, the coating layer is made of any one of calcium silicate, magnesium silicate, calcium aluminate, magnesium aluminate, calcium magnesium silicate, and calcium magnesium aluminate; and / or

[0007] The coating layer has a thickness of 20 to 40 μm.

[0008] In some embodiments, the average particle size of the phosphor particles is 15 μm to 3 mm; and / or

[0009] The phosphor particles are selected from SrAl2O4:Eu 2+ ,Dy 3+ 、SrAl2O4:Eu 2+、SrAl2O4:Eu 3+ 、SrAl2O4:Yb 2+ ,Re 3+ Any of .

[0010] In some embodiments, the reflective agent is selected from at least one of glass powder, glass beads, dolomite powder, and heavy calcium powder; and / or

[0011] The average particle size of the reflective agent is 10-180 μm;

[0012] In some embodiments, the filler is selected from at least one of iron tailings, copper tailings, and gold tailings; and / or

[0013] The average particle size of the filler is 5 to 40 μm.

[0014] In some embodiments, the silicon-aluminum-rich raw material is selected from at least one of granulated blast furnace slag, fly ash and metakaolin; wherein the mass ratio of the granulated blast furnace slag, the fly ash and the metakaolin is (0-25): (0-30): (50-100).

[0015] In some embodiments, the present application further provides a method for preparing a self-luminous geopolymer inorganic coating, comprising the following steps:

[0016] Providing phosphor particles and placing them in deionized water, then adding a first solution containing metal ions and a second solution containing acid ions, mixing and reacting to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent;

[0017] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0018] Taking corresponding weight parts of silicon-aluminum-rich raw materials and fillers, mixing them with the first premix, and stirring to obtain a self-luminous geopolymer inorganic coating;

[0019] The coating layer is composed of metal ions and acid ions; the metal ions are selected from at least one of calcium ions and magnesium ions; and the acid ions are selected from any one of silicate and aluminate.

[0020] In some embodiments,

[0021] The content of the metal ions in the second solution is 0.8 to 2.0 mol / L; and / or

[0022] The content of the acid radical ions in the third solution is 0.8 to 2.0 mol / L; and / or

[0023] The solid-liquid ratio of the phosphor particles to the deionized water is 1:100 to 1:500; and / or

[0024] The first solution is selected from any one of calcium nitrate solution, magnesium nitrate solution, calcium chloride solution, and magnesium chloride solution; and / or

[0025] The second solution is selected from any one of a sodium silicate solution, a potassium silicate solution, a sodium chlorate solution, and a potassium chlorate solution.

[0026] In some embodiments, phosphor particles are provided and placed in deionized water, and then a first solution containing metal ions and a second solution containing acid ions are added, mixed, and reacted to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent. The reaction temperature is 40 to 80°C and the reaction time is 6 to 12 hours.

[0027] In some embodiments, the metal ions consist of calcium ions and magnesium ions, and the molar ratio of the calcium ions to the magnesium ions is (0.85-1.15):1.

[0028] The beneficial effects of this application are:

[0029] The present application forms a coating layer on the surface of the phosphor particles, and the coating layer is composed of metal ions and acid ions; wherein the metal ions are selected from at least one of calcium ions and magnesium ions; the acid ions are selected from any one of silicate and aluminate; the material of the coating layer has a similar group structure to the silicon-aluminum-rich raw material, which can improve the compatibility of the coating layer with the geopolymer matrix obtained after the reaction of the silicon-aluminum-rich raw material, so that the released groups can fully participate in the geopolymerization reaction, ensuring that the strength development of the coating and the adhesion performance with concrete are not affected; on the other hand, the coating layer can isolate the phosphor particles from the strongly alkaline geopolymer matrix, forming a protective layer to inhibit the hydrolysis reaction of the phosphor particles, ensuring that the phosphor particles can exist stably for a long time, and thus ensuring the long-term luminescence effect of the phosphor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a scanning electron microscope photograph of phosphor particles with a calcium silicate gel layer coated on the surface;

[0032] Figure 2 Schematic diagram of the cross-sectional structure of phosphor particles with a calcium silicate gel layer coated on the surface;

[0033] Figure 3 These are initial luminescence photos of the inorganic coatings of Example 1, Comparative Example 1 and Comparative Example 4. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within the range. For example, description of a range from 1 to 6 should be considered to have specifically disclosed subranges 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., as well as individual numbers within that range, such as 1, 2, 3, 4, 5, and 6. Furthermore, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

[0035] The inventors of the present application have discovered that cement concrete is one of the most important building materials currently and is widely used in the construction of transportation infrastructure. Giving cement-based materials the ability to store and transmit light during the day and emit light at night has been one of the research hotspots of scientific and technological workers in the field of cement-based materials in recent years. Self-luminous concrete incorporates long-lasting fluorescent powder into concrete, allowing it to absorb and store sunlight during the day, and then slowly releases the energy stored in the fluorescent powder at night, continuously emitting light. Self-luminous concrete (such as applied to curbs, traffic signs, boat guide parts at toll stations, safety islands, concrete guardrails, etc.) can provide drivers who are driving at night or in environments with poor lighting conditions with good lane demarcation and driving vision. For example, in some sections of road with insufficient power and poor lighting, self-luminous concrete can very well prompt drivers with important information such as the direction of the road section, the condition of the curve and the correct lane, which can greatly reduce the probability of traffic accidents and is of great significance to improving road safety.

[0036] Since the construction of road traffic infrastructure has become mature, if the existing concrete components are dismantled as a whole and replaced with self-luminous concrete, the investment cost will be huge. Preparing self-luminous coatings and painting existing concrete components is a more effective and environmentally friendly construction method. Polymer materials, such as resins, styrene-butadiene rubber and polyvinyl alcohol, have the characteristics of high light transmittance, good rheological properties and easy coating construction. They can be used as a matrix and mixed with fluorescent powder to prepare organic self-luminous coatings. However, polymer matrix materials are prone to aging. Traffic infrastructure is exposed to strong sunlight all year round, and the self-luminous organic coatings applied to the surface of concrete components are prone to cracking and peeling, limiting their service life. In comparison, inorganic gelling materials have better durability. Inorganic self-luminous coatings prepared with cement-based materials as the matrix can also play a role in corrosion resistance and inhibiting chemical ion erosion when applied to the concrete surface, which can further improve the durability of the components. At present, extensive research has been carried out on self-luminous inorganic coatings, but there are still many technical problems that need to be solved. For example:

[0037] (1) The bonding strength between cement-based materials and concrete surfaces is poor, and the coating is easy to peel off after hardening, affecting the coating effect;

[0038] (2) Cement-based materials have low whiteness and poor light transmittance. To ensure the self-luminous effect, a large amount of fluorescent powder and reflective powder must be added to the cement-based materials. These powder particles do not participate in the cement hydration reaction and are likely to affect the strength development and bonding properties of the cement-based materials.

[0039] (3) Directly adding phosphors will affect the strength of geopolymers, etc., and since the phosphors themselves will also participate in alkaline hydrolysis and be consumed, it will affect the luminescent properties of the coating.

[0040] Therefore, based on the above problems, this application provides a self-luminous geopolymer inorganic coating and its preparation method. Detailed descriptions are given below. It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments.

[0041] The embodiment of the present application provides a self-luminous geopolymer inorganic coating, which includes, by weight: 100 parts of a silicon-aluminum-rich raw material, 50-90 parts of a liquid alkali activator, 60-100 parts of a fluorescent agent, 5-20 parts of a reflective agent, and 10-30 parts of a filler; wherein the fluorescent agent includes phosphor particles and a coating layer located on the surface of the phosphor particles, the coating layer being composed of metal ions and acid ions; the metal ions are selected from at least one of calcium ions and magnesium ions; and the acid ions are selected from any one of silicate and aluminate.

[0042] It is understood that in order to prevent the phosphor particles from affecting the gelling properties of the inorganic coating and to prevent the phosphor particles from hydrolyzing, the phosphor particles need to be surface treated. When a coating composed of metal ions and acid ions is formed on the surface of the phosphor particles, and the metal ions are selected from at least one of calcium ions and magnesium ions, and the acid ions are selected from either silicate or aluminate, the structure of the coating layer has similar groups and amorphous structure to the gel phase in the geopolymer matrix formed by the reaction of the silicon-aluminum-rich raw material. Therefore, the coating layer and the geopolymer matrix have good compatibility, allowing the coating layer to participate in the geopolymerization reaction. In a strong alkaline liquid phase environment, the nanocrystals coated on the outer layer of the phosphor particles can play a seed induction role, and the silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron dissolved from the silicon-aluminum-rich raw material are deposited and condensed on the surface of the phosphor particles, ultimately forming a gel phase product, which improves the cementing properties of the inorganic coating and promotes the strength development of the hardened body. Therefore, when the surface-coated fluorescent agent is added, the strength development of the geopolymer and the adhesion properties of the coating to the concrete surface are not affected. At the same time, the gel phase coating product layer can isolate the phosphor particles from the strongly alkaline geopolymer matrix, forming a protective layer to inhibit the hydrolysis reaction of the phosphor particles, ensuring that the phosphor particles can exist stably in the geopolymer matrix for a long time, thereby ensuring the long-term luminescence effect of the phosphor.

[0043] In some embodiments, the material of the coating layer is selected from any one of calcium silicate, magnesium silicate, calcium aluminate, magnesium aluminate, calcium magnesium silicate, and calcium magnesium aluminate.

[0044] In some embodiments, the coating layer has a thickness of 20 to 40 μm.

[0045] In some embodiments, the average particle size of the phosphor particles is between 15 μm and 3 mm. For example, the average particle size of the phosphor particles can be any one of 15 μm, 20 μm, 25 μm, 30 μm, 50 μm, 100 μm, 500 μm, 800 μm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm, or a range between any two of these values. When the average particle size of the phosphor particles falls within the above range, the luminous intensity will not be low due to the phosphor particles being too small, nor will the coating layer be difficult to form due to the phosphor particles being too large, thereby affecting the overall strength and bonding properties of the coating.

[0046] In some embodiments, the phosphor particles are selected from SrAl2O4:Eu 2+ ,Dy 3+ 、SrAl2O4:Eu 2+ 、SrAl2O4:Eu 3+ 、SrAl2O4:Yb 2+ ,Re 3+It is understood that SrAl2O4:Eu 2+ ,Dy 3+ It refers to aluminate long afterglow phosphor with strontium aluminate as matrix and doped with europium and dysprosium as activators. It emits yellow-green light with a wavelength of 520nm. Other SrAl2O4:Eu 2+ 、SrAl2O4:Eu 3+ 、SrAl2O4:Yb 2+ ,Re 3+ The only difference is the doping components, and the above-mentioned phosphor particles can be obtained commercially.

[0047] In some embodiments, the reflective agent is selected from at least one of glass powder, glass beads, dolomite powder, and heavy calcium powder. The addition of the reflective agent can further enhance the luminescent properties of the self-luminous geopolymer inorganic coating. Preferably, the reflective agent is white glass micropowder with a refractive index ≥1.90 and a transparency ≥95%.

[0048] In some embodiments, the average particle size of the reflective agent is 10-180 μm. For example, the average particle size of the reflective agent is any one of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, and 180 μm, or a range between any two of these values. It is understood that if the reflective agent particle size is less than 10 μm, the uncoated reflective agent particles will react with the geopolymer matrix, causing the reflective agent to dissolve under strong alkaline conditions, thereby losing its reflective effect. If the reflective agent particle size is greater than 180 μm, the reflective agent particles are too large to fully exert their reflective effect. Furthermore, their volume fraction in the geopolymer matrix is reduced, affecting their dispersion and thus failing to fully exert their reflective effect.

[0049] In some embodiments, the filler is selected from at least one of iron tailings, copper tailings, and gold tailings. The filler does not participate in the alkali excitation reaction. Therefore, adding a certain amount of filler to the same volume is equivalent to diluting the distribution of the silicon-aluminum-rich raw material particles in the geopolymer coating slurry. This effectively prevents a large amount of silicon-aluminum-rich raw material particles from completely coating the surface of the fluorescent agent or reflective agent, resulting in obstructed luminescence or reflection.

[0050] In some embodiments, the average particle size of the filler is 5 to 40 μm. For example, the average particle size of the filler is any one of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, and 40 μm, or a range between any two of these values.

[0051] In some embodiments, the silicon-aluminum-rich raw material is selected from at least one of granulated blast furnace slag, fly ash, and metakaolin; wherein the mass ratio of granulated blast furnace slag, fly ash, and metakaolin is (0-25): (0-30): (50-100). It can be understood that granulated blast furnace slag and fly ash are industrial by-products obtained in the processes of blast furnace pig iron smelting and coal-fired power generation, respectively, and are mainly latent gray and dark gray; metakaolin is high-temperature calcined kaolin, white and fine, and the geopolymer prepared with it as the main body has high whiteness and has little effect on the self-luminous effect of the phosphor. The above-mentioned silicon-aluminum-rich raw material is the main raw material for preparing geopolymers. After mixing with a liquid alkali activator, a geopolymer slurry is obtained. After solidification and hardening, the geopolymer slurry has high strength and a dense structure, and is the matrix of the self-luminous geopolymer inorganic coating.

[0052] In some embodiments, the liquid alkaline activator is prepared by mixing water with one or more of sodium hydroxide, sodium sulfate, sodium carbonate, and water glass (aqueous sodium silicate solution). The strong alkaline environment provided by the activator triggers the dissolution, polymerization, and gelation reactions of the silicon-aluminum-rich raw materials, thereby promoting the coagulation and hardening of the geopolymer slurry. The SiO2 content in the liquid activator is controlled within the range of 12-20%. The higher the SiO2 content, the more viscous the activator and the geopolymer slurry prepared with it become, facilitating the bonding of the geopolymer inorganic coating to the concrete structure.

[0053] In some embodiments, the present application also provides a method for preparing a self-luminous geopolymer inorganic coating, comprising the following steps:

[0054] Providing phosphor particles and placing them in deionized water, then adding a first solution containing metal ions and a second solution containing acid ions, mixing and reacting to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent;

[0055] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0056] Taking corresponding weight parts of silicon-aluminum-rich raw materials and fillers, mixing them with the first premix, and stirring to obtain a self-luminous geopolymer inorganic coating;

[0057] The coating layer is composed of metal ions and acid ions; the metal ions are selected from at least one of calcium ions and magnesium ions; and the acid ions are selected from any one of silicate and aluminate.

[0058] It is understandable that in the preparation process of the present application, after the surface treatment of the phosphor particles, the fluorescent agent, reflective agent and liquid alkali activator are first added simultaneously and stirred evenly. During the stirring process, the liquid alkali activator reacts with the coating layer on the surface of the fluorescent agent to release silicate ions, and at the same time reacts with the reflective agent and releases silicate ions. The active silicate ions in the liquid phase will adhere to each other, resulting in the fine reflective agent particles being evenly adhered to the fluorescent agent coating layer. The effective adhesion of the reflective agent can increase the light absorption and release effect of the fluorescent agent, and improve the brightness and duration of the fluorescent agent's luminescence; subsequently, a silicon-aluminum-rich raw material is added and stirred evenly, and a geopolymer coating with excellent luminescent properties can be prepared. It is worth noting that if the above raw materials are stirred together to form a slurry, it is easy to cause a large amount of aluminum silicate powder particles to be tightly coated on the surface of the fluorescent agent and reflective agent particles, thereby affecting the luminous efficiency.

[0059] In some embodiments, a sol-gel method is used to form a coating layer on the surface of the phosphor particles. Specifically, the phosphor particles are added to a three-necked flask and uniformly dispersed in deionized water under uniform stirring, which can provide attachment sites for the subsequent formation of the gel phase coating layer. Then two solutions are evenly added to the three-necked flask, one of which is a first solution containing metal ions and monovalent anions, and the other is a second solution containing monovalent cations and acid radical ion groups. The two solutions are added dropwise into the three-necked flask at a uniform speed, and after uniform reaction, a gel phase of the coating material is generated. Since the phosphor particles in the solution provide attachment sites for the gel phase, the gel phase product (calcium silicate, magnesium silicate, calcium aluminate, magnesium aluminate, calcium magnesium silicate, calcium magnesium aluminate, etc.) is coated on the surface of the phosphor particles to form a coating product layer. The coating layer is mainly composed of divalent cations (Ca 2+ or Mg 2+ ) and anionic groups (silicate or aluminate). This gel-phase product shares similar groups and amorphous structure with the calcium aluminosilicate gel phase in the geopolymer matrix, resulting in excellent compatibility between the coated product layer and the geopolymer matrix. The addition of a surface-coated fluorescent agent to the component does not affect the strength development of the geopolymer or the adhesion properties of the geopolymer coating to the concrete surface. Furthermore, the gel-phase coated product layer isolates the fluorescent agent from the strongly alkaline geopolymer matrix, forming a protective layer that inhibits its hydrolysis, ensuring its long-term stable presence in the geopolymer matrix and, consequently, its long-term luminescence.

[0060] In some embodiments, the content of metal ions in the second solution is 0.8 to 2.0 mol / L, for example, any one of 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, and 2.0 mol / L, or a range between any two of these values.

[0061] In some embodiments, the content of acid ions in the third solution is 0.8 to 2.0 mol / L, for example, any one of 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, and 2.0 mol / L, or a range between any two of these values.

[0062] In some embodiments, the solid-liquid ratio of the phosphor particles to deionized water is 1:100 to 1:500, preferably 1:200.

[0063] In some embodiments, the first solution is selected from any one of calcium nitrate solution, magnesium nitrate solution, calcium chloride solution, and magnesium chloride solution.

[0064] In some embodiments, the second solution is selected from any one of a sodium silicate solution, a potassium silicate solution, a sodium chlorate solution, and a potassium chlorate solution.

[0065] In some embodiments, phosphor particles are provided and placed in deionized water, and then a first solution containing metal ions and a second solution containing acid ions are added, mixed, and reacted to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent. The reaction temperature is 40 to 80°C and the reaction time is 6 to 12 hours.

[0066] In some embodiments, in order to further improve the performance of the coating layer, the metal ions are composed of calcium ions and magnesium ions, and the molar ratio of calcium ions to magnesium ions is (0.85-1.15):1.

[0067] It is understandable that the gel phase product (such as calcium silicate, calcium aluminate) formed by calcium ions has a faster development of strength and has a good bonding effect, and is more compatible with the geopolymer matrix. Therefore, promoting the generation of such gel phase products during the coating process can effectively improve the bonding properties of the coating material, thereby improving the bonding properties of the geopolymer coating and promoting its early strength development. The gel phase product (such as magnesium silicate, magnesium aluminate) formed by magnesium ions has a slower development of strength and is less compatible with the geopolymer matrix than calcium-based products. Therefore, promoting the generation of magnesium-based products can reduce the bonding properties of the coating material and reduce the bonding properties of the geopolymer coating. It is worth noting that, precisely because the magnesium-based coating has a poor compatibility with the geopolymer slurry, it can be stably present in the geopolymer matrix for a long time, thereby effectively protecting the fluorescent agent particles from hydrolysis reaction, ultimately improving the luminescent properties of the geopolymer coating. Therefore, the molar ratio of calcium ions to magnesium ions needs to be controlled in the range of 0.85-1.15. If the molar ratio is too high, the luminescence of the coating will be seriously damaged; if the molar ratio is too low, the adhesion properties of the coating will be significantly reduced.

[0068] In order to make the above implementation details and operations of the present application clearly understood by those skilled in the art, as well as to demonstrate the significant improvement in performance of the self-luminous geopolymer inorganic coating and its preparation method in the embodiment of the present application, the above technical solution is illustrated by multiple embodiments below.

[0069] Example 1

[0070] Provided is a self-luminous geopolymer inorganic coating comprising: 100 parts of a silicon-aluminum-rich raw material, 70 parts of a fluorescent agent, 10 parts of a reflective agent, 30 parts of a filler, and 70 parts of a liquid alkaline activator. The silicon-aluminum-rich raw material is granulated blast furnace slag and metakaolin in a mass ratio of 10:90; the liquid alkaline activator is a mixture of sodium hydroxide, water glass, and water, with a SiO2 content of 15%; the fluorescent agent is phosphor particles with a particle size of 70 to 100 μm, coated with a calcium silicate layer; the reflective agent is glass powder with an average particle size of 40 μm; and the filler is iron tailings powder with an average particle size of 5 μm.

[0071] The specific preparation process is:

[0072] Phosphor particles were placed in deionized water at a solid-liquid ratio of 1:200 and stirred at 50 rpm at 60°C. 0.8 mol / L calcium nitrate solution and 0.8 mol / L sodium silicate solution were then added, mixed, and reacted at 50°C for 6 hours. The resulting solid phase was filtered and washed three times with ethanol and dried at 105°C to form a coating layer on the surface of the phosphor particles, thereby obtaining a fluorescent agent.

[0073] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0074] Corresponding weight portions of silicon-aluminum-rich raw materials and fillers are mixed with the first premix, and stirred to obtain a self-luminous geopolymer inorganic coating.

[0075] Example 2

[0076] Provided is a self-luminous geopolymer inorganic coating comprising: 100 parts of alumina-silicon-rich raw materials, 50 parts of a fluorescent agent, 5 parts of a reflective agent, 15 parts of a filler, and 90 parts of a liquid alkaline activator. The alumina-silicon-rich raw materials are granulated blast furnace slag, fly ash, and metakaolin in a mass ratio of 30:10:60; the liquid alkaline activator is a mixture of sodium hydroxide, water glass, and water, with a SiO2 content of 15%; the fluorescent agent is phosphor particles with a particle size of 15 to 45 μm, coated with a magnesium silicate layer; the reflective agent is glass powder with an average particle size of 100 μm; and the filler is copper tailings powder with an average particle size of 30 μm.

[0077] The specific preparation process is:

[0078] Phosphor particles were placed in deionized water at a solid-liquid ratio of 1:200 and stirred at 50 rpm at 60°C. 1.0 mol / L calcium nitrate solution and 1.5 mol / L sodium silicate solution were then added, mixed, and reacted at 40°C for 12 hours. The resulting solid phase was filtered and washed three times with ethanol and dried at 105°C to form a coating layer on the surface of the phosphor particles, thereby obtaining a fluorescent agent.

[0079] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0080] Corresponding weight portions of silicon-aluminum-rich raw materials and fillers are mixed with the first premix, and stirred to obtain a self-luminous geopolymer inorganic coating.

[0081] Example 3

[0082] A self-luminous geopolymer inorganic coating is provided, comprising: 100 parts of a silicon-aluminum-rich raw material, 90 parts of a fluorescent agent, 20 parts of a reflective agent, 25 parts of a filler, and 60 parts of a liquid alkaline activator. The silicon-aluminum-rich raw material is blast furnace slag and fly ash, with a mass ratio of 50:50; the liquid alkaline activator is a mixture of sodium hydroxide, water glass, and water, with a SiO2 content of 10%; the fluorescent agent is phosphor particles with a particle size of 1 to 3 mm, coated with a calcium aluminate layer; the reflective agent is glass powder with an average particle size of 80 μm; and the filler is gold tailings powder with an average particle size of 40 μm.

[0083] The specific preparation process is:

[0084] Phosphor particles were placed in deionized water at a solid-liquid ratio of 1:150 and stirred at 50 rpm at 60°C. 1.2 mol / L calcium nitrate solution and 1.2 mol / L sodium silicate solution were then added, mixed, and reacted at 80°C for 8 hours. The resulting solid phase was filtered and washed three times with ethanol and dried at 105°C to form a coating layer on the surface of the phosphor particles, thereby obtaining a fluorescent agent.

[0085] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0086] Corresponding weight portions of silicon-aluminum-rich raw materials and fillers are mixed with the first premix, and stirred to obtain a self-luminous geopolymer inorganic coating.

[0087] Example 4

[0088] Provided is a self-luminous geopolymer inorganic coating comprising: 100 parts of a silicon-aluminum-rich raw material, 90 parts of a fluorescent agent, 30 parts of a reflective agent, 30 parts of a filler, and 70 parts of a liquid alkaline activator. The silicon-aluminum-rich raw material is granulated blast furnace slag and metakaolin in a ratio of 10:90; the liquid alkaline activator is a mixture of sodium hydroxide, water glass, and water, with a SiO2 content of 10%; the fluorescent agent is phosphor particles with a particle size of 70 to 100 μm, coated with a calcium magnesium silicate layer; the reflective agent is glass powder with an average particle size of 40 μm; and the filler is iron tailings powder with an average particle size of 5 μm.

[0089] The specific preparation process is:

[0090] Phosphor particles were placed in deionized water at a solid-liquid ratio of 1:200 and stirred at 50 rpm at 60°C. 0.85 mol / L calcium nitrate solution, 1.0 mol / L magnesium nitrate solution, and 2.0 mol / L sodium silicate solution were then added, mixed, and reacted at 60°C for 6 hours. The resulting solid phase was filtered and washed three times with ethanol and dried at 105°C to form a coating layer on the surface of the phosphor particles, thereby obtaining a fluorescent agent. The molar ratio of calcium ions to magnesium ions in the coating layer was 0.85:1.

[0091] Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix;

[0092] Corresponding weight portions of silicon-aluminum-rich raw materials and fillers are mixed with the first premix, and stirred to obtain a self-luminous geopolymer inorganic coating.

[0093] Examples 5-7

[0094] The specific raw material amounts and preparation process are the same as those in Example 4, except that the molar ratio of calcium ions to magnesium ions in the coating layer is different.

[0095] Comparative Example 1

[0096] The specific raw material amounts and preparation process are the same as those in Example 1, except that the fluorescent agent has not been subjected to surface gel coating modification treatment.

[0097] Comparative Example 2

[0098] The specific raw material dosage and preparation process are the same as those in Example 1, except that no solid waste filler is added to the system.

[0099] Comparative Example 3

[0100] The specific raw material amounts and preparation process are the same as those in Example 1, except that no reflective agent is added to the system.

[0101] Comparative Examples 4-5

[0102] The specific raw material dosage and preparation process are the same as those in Example 4, except that the molar ratio of calcium ions to magnesium ions in the coating layer does not satisfy the range of (0.85-1.15):1.

[0103] The 24h compressive strength, 28d compressive strength, bonding strength with concrete components and initial luminous intensity of the inorganic coating hardened bodies obtained in Examples 1-7 and Comparative Examples 1-5 were tested, as shown in Table 1.

[0104] Table 1

[0105]

[0106]

[0107] As can be seen from Table 1, the self-luminous inorganic coating prepared with geopolymer as the matrix has better durability than organic coatings and good compatibility with concrete components, which extends the service life of the self-luminous coating. Compared with cement-based coatings, geopolymer coatings have stronger adhesion to concrete components, and the bonding strength can reach 1.60~1.85MPa.

[0108] The sol-gel method is used to coat the surface of the phosphor particles with a calcium silicate gel product layer, which improves the reactivity of the phosphor in the geopolymer matrix and reduces its negative effects on the strength development and bonding properties of the inorganic coating. Even if the fluorescent agent dosage is increased to 100 parts, the setting time of the geopolymer inorganic coating can still be controlled within 2 hours, the 24h compressive strength is ≥14MPa, and the 28d compressive strength is ≥32.5MPa.

[0109] The geopolymer is prepared with white metakaolin as the main raw material, and the addition of ultra-fine ground tailings powder can effectively improve the whiteness of the matrix. The added reflective powder also ensures the luminous performance of the inorganic coating, and the maximum luminous intensity can reach 7500mcd / m 2 , after 8 hours it dropped to 135mcd / m 2 It is still higher than the minimum brightness that the human eye can perceive.

[0110] Compared with Comparative Example 1, Example 1 has higher compressive strength and bonding strength, and the initial luminescence performance is also higher than that of Comparative Example 1, indicating that the coating effect of the phosphor in Example 1 is more excellent, which not only ensures the strength development of the geopolymer inorganic coating, but also improves the stability of the phosphor; compared with Comparative Example 2, Example 1 has higher compressive strength and bonding strength, and the initial luminescence performance is also higher than that of Comparative Example 2; compared with Comparative Example 3, Example 1 has lower compressive strength and bonding strength, indicating that the coating layer of Comparative Example 3 has better compatibility with the geopolymer inorganic coating and stronger interface adhesion, but the luminescence performance of Comparative Example 3 is significantly reduced, indicating that the stability of the phosphor is seriously affected. Compared with Comparative Examples 4-5, in Examples 4-7, when the molar ratio of calcium ions to magnesium ions is within (0.85-1.15): 1, the structural stability of the coating layer can be further ensured, and cracking of the coating layer during the preparation of the geopolymer inorganic coating can be avoided, and the infiltration of the liquid alkaline activator can be avoided, resulting in a decrease in the stability of the phosphor. If it is not within the above range, the luminescent performance of the geopolymer inorganic coating will be reduced.

[0111] See also Figure 1 , wherein (a) shows the microscopic morphology of the fluorescent agent provided by the present application, with the surface uniformly covered with a coral-like gel phase coating layer; (b) shows the microscopic morphology of the polished cross-section of the fluorescent agent, with the thickness of the surface gel phase coating layer being approximately 20 to 40 μm. Figure 2 , showing a schematic diagram of the cross-sectional structure of a fluorescent agent with a calcium silicate gel coating layer formed on the surface.

[0112] See also Figure 3 , respectively, are the initial luminescence conditions of the inorganic coatings of Example 1, Comparative Example 1, and Comparative Example 4: where (a) represents Example 1, (b) represents Comparative Example 1, and (c) represents Comparative Example 4. As can be seen from the figure, for Comparative Example 1, if the phosphor particles are not surface-coated and modified, the self-luminous properties of the inorganic coating are severely affected. Under the strong alkaline conditions of the geopolymer, although the uncoated phosphor does not participate in the geopolymer reaction and cannot contribute to the gelling properties, it is still corroded by the alkaline reaction, causing the luminescent component strontium aluminate to react with the hydroxyl group and hydrolyze, ultimately affecting the stability and luminescence properties of the phosphor. For Comparative Example 4, although the phosphor was surface-coated and modified, the ratio of calcium ions to magnesium ions was too low, causing them to participate in the geopolymer reaction and be gradually consumed, which to some extent affected the protective isolation effect of the coating layer and reduced the luminescence properties of the phosphor.

[0113] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0114] The products and preparation methods provided in the examples of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A self-luminous geopolymer inorganic coating, characterized in that: The composition comprises, by weight, 100 parts of a silicon-aluminum-rich raw material, 50-90 parts of a liquid alkali activator, 60-100 parts of a fluorescent agent, 5-20 parts of a reflective agent, and 10-30 parts of a filler. The fluorescent agent includes fluorescent particles and a coating layer located on the surface of the fluorescent particles, wherein the coating layer is composed of metal ions and acid ions; wherein the metal ions are composed of calcium ions and magnesium ions, and the molar ratio of the calcium ions to the magnesium ions is (0.85-1.15):1; the acid ions are selected from any one of silicate and aluminate; and the material of the coating layer is selected from any one of calcium magnesium silicate and calcium magnesium aluminate.

2. The self-luminous geopolymer inorganic coating according to claim 1, characterized in that: The thickness of the coating layer is 20-40 μm.

3. The self-luminous geopolymer inorganic coating according to claim 1, characterized in that: The average particle size of the phosphor particles is 15 μm to 3 mm; and / or The phosphor particles are selected from SrAl2O4:Eu 2+ ,Dy 3+ 、SrAl2O4:Eu 2+ 、SrAl2O4:Eu 3+ 、SrAl2O4:Yb 2+ ,Re 3+ Any of .

4. The self-luminous geopolymer inorganic coating according to claim 1, characterized in that: The reflective agent is selected from at least one of glass powder, glass beads, dolomite powder and heavy calcium powder; and / or The average particle size of the reflective agent is 10-180 μm.

5. The self-luminous geopolymer inorganic coating according to claim 1, characterized in that: The filler is selected from at least one of iron tailings, copper tailings, and gold tailings; and / or The average particle size of the filler is 5-40 μm.

6. The self-luminous geopolymer inorganic coating according to claim 1, characterized in that: The silicon-aluminum-rich raw material is selected from at least one of granulated blast furnace slag, fly ash and metakaolin; wherein the mass ratio of the granulated blast furnace slag, the fly ash and the metakaolin is (0-25): (0-30): (50-100).

7. A method for preparing the self-luminous geopolymer inorganic coating according to any one of claims 1 to 6, characterized in that: The steps include: Providing phosphor particles and placing them in deionized water, then adding a first solution containing metal ions and a second solution containing acid ions, mixing and reacting to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent; Taking corresponding parts by weight of a fluorescent agent, a reflective agent and a liquid alkaline activator, and mixing them to obtain a first premix; Taking corresponding weight parts of silicon-aluminum-rich raw materials and fillers, mixing them with the first premix, and stirring to obtain a self-luminous geopolymer inorganic coating; The coating layer is composed of metal ions and acid ions; the metal ions are composed of calcium ions and magnesium ions, and the molar ratio of the calcium ions to the magnesium ions is (0.85-1.15):1; the acid ions are selected from any one of silicate and aluminate.

8. The method for preparing a self-luminous geopolymer inorganic coating according to claim 7, wherein: The content of the metal ions in the first solution is 0.8 to 2.0 mol / L; and / or The content of the acid radical ions in the second solution is 0.8 to 2.0 mol / L; and / or The solid-liquid ratio of the phosphor particles to the deionized water is 1:100 to 1:500; and / or The first solution is selected from any one of calcium nitrate solution, magnesium nitrate solution, calcium chloride solution, and magnesium chloride solution; and / or The second solution is selected from any one of a sodium silicate solution, a potassium silicate solution, a sodium aluminate solution, and a potassium aluminate solution.

9. The method for preparing a self-luminous geopolymer inorganic coating according to claim 7, wherein: In the step of providing phosphor particles and placing them in deionized water, then adding a first solution containing metal ions and a second solution containing acid ions, mixing, and reacting to form a coating layer on the surface of the phosphor particles and obtain a fluorescent agent, the reaction temperature is 40~80°C and the reaction time is 6~12 hours.

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