High-strength water-absorbing material as well as preparation method and application thereof

Abstract

The invention provides a high-strength water-absorbing material and a preparation method and application thereof, and relates to the technical field of novel wall materials, the preparation method comprises the following steps: S1, stirring and mixing an alkaline activator, white mud and water to obtain a hydrated mixture; s2, filtering the hydrated mixture to obtain mixed wet mud; and S3, carrying out ball milling on the mixed wet mud and fly ash, and roasting after ball milling to obtain the high-strength water-absorbing material. Stable silicate wet mud is generated through hydration treatment of white mud and then mixed with fly ash for ball milling, particles are reduced, and the chance of reaction with carbon dioxide is increased. Carbon dioxide is introduced into ball milling for carbonization, so that CO2 is consumed, and a high-temperature roasting chemical basis is provided. Finally, the fly ash forms a porous structure through high-temperature roasting, the water absorption is remarkably improved, a wide prospect is provided for fly ash recycling, and resource recycling and environmental protection benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of new wall materials, and particularly to a high-strength water-absorbing material, a preparation method thereof, and an application thereof. Background Art

[0002] After the fly ash is treated by the aluminum extraction process, the residual waste slag is more harmful to the environment than the original fly ash before aluminum extraction. This is mainly because during the aluminum extraction process, the original glass microsphere structure of the fly ash is severely damaged, and the glass particles also undergo significant corrosion, resulting in the transformation of the residue particles into a loose and porous structure. This structural change endows the fly ash residue with characteristics such as fine particle size, increased specific surface area, and enhanced activity. The fine particle size means that the residue is more likely to be scattered by the wind, increasing the risk of air pollution; the increase in specific surface area enables the residue to adsorb more harmful substances, which may enter water bodies and soil through rainwater scouring and other means if not properly treated, causing long-term and irreversible damage to the ecological environment.

[0003] Therefore, how to treat the residue after aluminum extraction from fly ash has become an essential and crucial link in the fly ash aluminum extraction technology chain. This link not only concerns environmental protection but also directly affects the sustainable development and wide application of the fly ash aluminum extraction technology. With the continuous progress and maturity of the fly ash aluminum extraction technology, the urgency and importance of the residue treatment problem have become increasingly prominent.

[0004] White mud, the name comes from its specific identity in the fly ash acid method aluminum extraction industry process - it is produced as the main waste residue of the process. Fly ash, a solid waste from coal-fired power plants, undergoes a series of complex chemical reactions, and the aluminum element inside is extracted, and the remaining residue forms what we call white mud. The chemical composition of white mud is extremely rich, mainly silicon oxide (SiO2) and aluminum oxide (Al2O3). In white mud, SiO2 and Al2O3 do not exist in the form of independent compounds, but together with other oxides (such as magnesium oxide, calcium oxide, etc.) form a complex glassy structure. This glassy SiO2 and Al2O3 are tightly bound by strong chemical bonds to form a disordered network architecture. Specifically, the silicon atoms and oxygen atoms of SiO2 are connected by covalent bonds to form a tetrahedral structure. These tetrahedral structures are further connected to each other through shared oxygen atoms, expanding into a three-dimensional network. At the same time, there are two possible ways for aluminum atoms in Al2O3 to combine: one is to replace the position of some silicon atoms, and the other is to combine with oxygen atoms to form a six-coordinated octahedral structure. These octahedral structures are then connected to tetrahedral structures by sharing oxygen atoms, making the entire network structure more complex. Because the chemical bonds between SiO2 and Al2O3 are extremely strong, this glassy structure shows extremely high stability and is difficult to destroy. In addition, because the atoms in the network structure are arranged very closely, this glassy SiO2 and Al2O3 therefore have a very high hardness. More importantly, since it takes extremely high energy to destroy the chemical bonds in this network structure, the melting point of this glassy SiO2 and Al2O3 is also quite high.

[0005] However, everything has its two sides. While enjoying the benefits of aluminum extraction technology from high-aluminum fly ash, we must also face up to the environmental problems it brings. White mud, the waste residue produced during the aluminum extraction process, is extremely acidic. If it is not properly treated, it will pose a serious threat to water bodies and storage environments. Once the acidic substances in the white mud enter the water body, they will quickly dissolve and release a large amount of hydrogen ions, causing water acidification and thus destroying the balance of the aquatic ecosystem. At the same time, the strong acidity of the white mud may also cause serious corrosion to the soil in the storage environment, change the pH of the soil, and affect soil fertility and plant growth.

[0006] Therefore, how to properly deal with the white mud waste generated during the aluminum extraction process has become an environmental problem that needs to be solved urgently. We need to explore a white mud treatment solution that is both economical and environmentally friendly through the dual drive of scientific and technological innovation and environmental protection policies, so as to achieve the win-win goal of sustainable development of fly ash aluminum extraction technology and environmental protection. Summary of the invention

[0007] The object of the present invention is to provide a high-strength water-absorbing material, its preparation method and application. By hydrating white mud with an alkaline activator, the acidic substances in the white mud are effectively released and neutralized, and at the same time, stable silicate wet mud is generated. Further, mixing the silicate wet mud with fly ash and ball milling not only realizes the uniform mixing of the two, but also reduces the particle size of the silicate wet mud, increasing its reaction chance with carbon dioxide. Introducing carbon dioxide for carbonization reaction during the ball milling process not only consumes carbon dioxide in the air and realizes carbon fixation, but also provides a chemical basis for subsequent high-temperature roasting. Finally, through high-temperature roasting, the structure of fly ash changes to form a porous structure, significantly improving its water absorption and providing a broad application prospect for the reuse of fly ash.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a preparation method of a high-strength water-absorbing material, comprising the following steps:

[0010] S1: Stir and mix an alkaline activator, white mud and water to obtain a hydrated mixture;

[0011] S2: Filter the hydrated mixture to obtain a mixed wet mud;

[0012] S3: Ball mill the mixed wet mud and fly ash, and perform roasting after ball milling to obtain a high-strength water-absorbing material.

[0013] Further, on the basis of the above technical solution, in step S1, the stirring and mixing specifically includes the following steps:

[0014] Place the alkaline activator, white mud and water in a reaction kettle, and under the condition of a temperature of 120 - 140 °C, perform heating and stirring at a stirring rate of 400 - 500 r / min for 1 - 2 h. When the temperature cools to 50 - 60 °C, stop stirring;

[0015] and / or, the reaction kettle is a magnetic stirring reaction kettle;

[0016] The alkaline activator includes one or more of calcium hydroxide, calcium carbonate, and calcium bicarbonate.

[0017] Further, on the basis of the above technical solution, in step S2, the filtration means filtering the hydrated mixture with a gauze to obtain a mixed wet mud;

[0018] The water content of the mixed wet mud is 50 - 60%.

[0019] Further, on the basis of the above technical solution, in step S3, the conditions of the ball milling include:

[0020] The equipment for ball milling is a wet ball mill;

[0021] The mass ratio of the balls to the total mass of the mixed wet mud and fly ash is (2 - 3):1;

[0022] The ball milling time is 4 - 6 h;

[0023] The ball milling rate is 100 - 300 r / min;

[0024] The ball milling medium is water.

[0025] Further, on the basis of the above technical solution, in step S3, the conditions for roasting are:

[0026] The temperature is 800 - 1000 °C, and the roasting time is 2 - 3 h.

[0027] Further, on the basis of the above technical solution, in step S1, the mass ratio of the alkaline activator, white mud, and water is (2 - 3):1:(5 - 8);

[0028] In step S3, the mass ratio of the mixed wet mud to the fly ash is 1:(1 - 3).

[0029] The present invention also provides a high-strength water-absorbing material prepared by the preparation method of the high-strength water-absorbing material as described above.

[0030] The present invention also provides an application of the high-strength water-absorbing material prepared by the preparation method of the high-strength water-absorbing material as described above or the high-strength water-absorbing material as described above, which can be used for preparing permeable bricks.

[0031] Further, on the basis of the above technical solution, the preparation method of the permeable brick includes the following steps:

[0032] (1) Stir and mix the high-strength water-absorbing material and the aggregate, and then add water and continue to stir to obtain the raw material for the permeable brick;

[0033] (2) Place the raw material for the permeable brick in a mold and press it to obtain a brick blank;

[0034] (3) Perform autoclave curing on the brick blank to obtain the permeable brick.

[0035] Further, on the basis of the above technical solution, the aggregate includes cement, slag, and metakaolin;

[0036] The mass ratio of the high-strength water-absorbing material to the aggregate is 1:(1 - 3);

[0037] The conditions for the autoclave curing include:

[0038] The temperature is 180 - 200 °C; the pressure is 0.8 - 1.2 MPa; the time is 6 - 8 h.

[0039] A high-strength water-absorbing material provided by the present invention, its preparation method and application have the following beneficial effects:

[0040] 1. By subjecting white mud and an alkaline activator to hydration treatment, the present invention effectively releases and neutralizes the acidic substances in the white mud, and at the same time generates stable silicate wet mud. Further, mixing the silicate wet mud with fly ash and ball-milling not only achieves the uniform mixing of the two, but also reduces the particle size of the silicate wet mud, increasing its reaction opportunity with carbon dioxide. Introducing carbon dioxide for carbonization reaction during the ball-milling process not only consumes carbon dioxide in the air, achieving carbon fixation, but also provides a chemical basis for subsequent high-temperature roasting. Finally, after high-temperature roasting, the structure of the fly ash changes to form a porous structure, significantly improving its water absorption and providing a broad application prospect for the reuse of fly ash.

[0041] 2. The high-strength water-absorbing material prepared by the present invention is applied to the production of permeable bricks. This application not only endows the permeable bricks with excellent mechanical properties, ensuring their stability and durability in various complex environments, but also significantly improves their water permeability coefficient.

[0042] 3. The permeable bricks prepared by the present invention also have good environmental protection performance. During the preparation process, through the effective utilization of white mud and fly ash, not only the recycling of resources is realized, reducing environmental pollution, but also through steps such as carbonization reaction and high-temperature roasting, the carbon emissions of the material are further reduced, meeting the current globally advocated development concept of green, low-carbon and environmental protection. Specific embodiments

[0043] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. The process parameters without specific conditions noted in the following embodiments are usually in accordance with conventional conditions.

[0044] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0045] According to the first aspect of the present invention, there is provided a method for preparing a high-strength water-absorbing material, comprising the following steps:

[0046] S1: Stir and mix an alkaline activator, white mud and water to obtain a hydrated mixture;

[0047] S2: Filter the hydrated mixture to obtain a mixed wet mud;

[0048] S3: Ball-mill the mixed wet mud and fly ash, and perform roasting after ball-milling to obtain a high-strength water-absorbing material.

[0049] Specifically, the present invention first performs a hydration treatment on white mud and an alkaline activator. The main purpose of this step is to effectively release the acidic substances in the white mud by adding an appropriate amount of alkali, and through subsequent neutralization reactions, neutralize these acidic substances, and at the same time lay a foundation for the formation of silicate wet mud. After the hydration treatment of the white mud, oxides such as SiO2 and Al2O3 in it form a more stable silicate structure with other components. Next, the hydrated silicate wet mud is mixed with fly ash and sent into a ball mill for sufficient ball-milling. During the ball-milling process, the silicate wet mud and fly ash particles collide and rub violently under the action of mechanical force. This not only realizes the uniform mixing between the two, but also further reduces the particle size of the silicate wet mud, increasing its chance of contact with carbon dioxide in the air. At the same time as ball-milling, carbon dioxide in the air is introduced for a carbonization reaction. In this step, the silicate components in the silicate wet mud react chemically with carbon dioxide to form carbonates. This reaction not only consumes carbon dioxide in the air and realizes carbon fixation, but also provides a necessary chemical basis for the subsequent high-temperature roasting process. Finally, the mixture after the carbonization reaction is sent into a high-temperature roasting furnace for roasting. Under high-temperature conditions, the carbonates react further with the components in the fly ash, resulting in a change in the structure of the fly ash, forming a porous-structured mixture. This porous structure not only significantly increases the surface area of the fly ash, but also provides more water-absorbing channels and sites for it, thus greatly improving the water absorption of the fly ash.

[0050] As an optional embodiment of the present invention, the alkaline activator includes one or more of calcium hydroxide, calcium carbonate, and calcium bicarbonate.

[0051] Specifically, the purpose of selecting the calcium-containing alkaline activator in the present invention is that it can chemically react with the silicate components in white mud during the hydration reaction to form calcium silicate salts. The calcium silicate salts will further undergo a carbonation reaction with carbon dioxide in the air. During this process, the calcium ions in the calcium silicate salts combine with carbon dioxide to form calcium carbonate salts. The calcium carbonate salts formed will exhibit a porous structure during the formation process, and this structural characteristic endows it with unique physical and chemical properties. The porous calcium carbonate salts not only have a large specific surface area but also provide abundant micropores and channels, providing good conditions for subsequent mineralization reactions. The porous calcium carbonate salts will undergo a deep mineralization reaction with fly ash. During this reaction process, the calcium-containing porous substances will effectively penetrate and fill the pores and cracks of fly ash and undergo chemical bonding and physical interweaving with the mineral components inside. This mineralization reaction not only changes the microstructure of fly ash but also makes it porous as a whole. The formation of porous fly ash not only greatly increases its surface area but also provides more water absorption channels and sites, thus significantly improving the water absorption of fly ash.

[0052] As an alternative embodiment of the present invention, in step S1, the stirring and mixing specifically include the following steps:

[0053] Place the alkaline activator, white mud, and water in a reaction kettle, and under the condition of a temperature of 120 - 140 °C, carry out heating and stirring at a stirring rate of 400 - 500 r / min for 1 - 2 h. When the temperature cools to 50 - 60 °C, stop stirring;

[0054] And / or, the reaction kettle is a magnetic stirring reaction kettle.

[0055] As an alternative embodiment of the present invention, in step S2, the filtration means filtering the hydrated mixture with gauze to obtain a mixed wet mud.

[0056] As an alternative embodiment of the present invention, the water content of the mixed wet mud is 50 - 60% (such as 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, etc.).

[0057] Specifically, during the ball milling process, the reaction between the silicate component in the mixed wet mud and carbon dioxide in the air is one of the key steps in the present invention. When the silicate reacts with carbon dioxide, a certain amount of moisture is required as a reaction medium to promote the diffusion of gas molecules and the contact of reactants. When the moisture content is within the range of 50-60%, the silicate component in the mixed wet mud can fully contact and react with carbon dioxide in the air to generate the required calcium silicate salts. This reaction process is not only efficient but also stable, laying a solid foundation for the subsequent carbonation reaction and mineralization reaction. If the moisture content of the mixed wet mud is low, i.e., below 50%, the reaction rate between the silicate and carbon dioxide will decrease significantly. This is because moisture plays a role of lubrication and conduction in the reaction. Insufficient moisture content will limit the contact area and reaction rate of the reactants, making the entire reaction process slow and lengthy. This will not only prolong the ball milling time, increase energy consumption and costs, but also may affect the quality and performance of the final product. On the contrary, if the moisture content of the mixed wet mud is high, i.e., exceeding 60%, it will also have an adverse effect on the reaction. Excessive moisture content will make the mixed wet mud too thin, reducing the contact area between silicate components and lowering the reaction efficiency. In addition, excessive moisture will increase the complexity and instability of the reaction system, possibly leading to the occurrence of side reactions or a decrease in the quality of reaction products. More importantly, excessive moisture content will also increase the difficulty of subsequent drying and treatment, further increasing production costs and time.

[0058] As an alternative embodiment of the present invention, in step S3, the conditions of the ball milling include:

[0059] The equipment for ball milling is a wet ball mill; the ball-to-material ratio of ball milling is (2-3):1, zirconia balls are selected, the ball milling time is 4-6 h (such as 4.5 h, 5 h, 5.5 h, etc.), the ball milling rate is 100-300 r / min (such as 120 r / min, 140 r / min, 160 r / min, 180 r / min, 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, etc.), and the ball milling medium is water.

[0060] Specifically, controlling the ball milling time within 4-6 h can ensure that the silicate component in the mixed wet mud reacts fully with carbon dioxide in the air;

[0061] The present invention also limits the ball milling rate to 100-300 r / min. This rate setting is based on in-depth research on the characteristics of the mixed wet mud and chemical reaction kinetics. Within this rate range, the mixed wet mud is subjected to appropriate mechanical force in the ball mill, which can be fully dispersed and maintain a certain particle size, so as to maximize the contact and reaction with carbon dioxide in the air.

[0062] If the ball milling rate is relatively low, i.e., below 100 r / min, the particles in the mixed wet mud will not be sufficiently ground and dispersed, and the reaction between the silicate component and carbon dioxide will be restricted, resulting in incomplete reaction and ultimately affecting the performance of the bricks. In addition, too low a rate will also prolong the ball milling time, increasing energy consumption and production costs.

[0063] On the contrary, if the ball milling rate is too high, i.e., exceeding 300 r / min, although it seemingly can accelerate the dispersion of the mixed wet mud, it may actually bring a series of negative impacts. Too high a rate will cause the particles of the mixed wet mud to collide and rub excessively in the ball mill, generating too much heat and wear, and may even damage the formed silicate structure. In addition, too fast a ball milling rate may also make the mixed wet mud too delicate, increasing its surface area and adsorption capacity, thus making it easier to absorb moisture and other impurities in the air, affecting the quality and stability of the final product.

[0064] As an optional implementation manner of the present invention, in step S3, the conditions for roasting are as follows:

[0065] The temperature is 800 - 1000 °C (such as 850 °C, 900 °C, 950 °C, etc.), and the roasting time is 2 - 3 h (such as 2.2 h, 2.4 h, 2.6 h, 2.8 h, etc.).

[0066] Specifically, the present invention defines the roasting temperature as 800 - 1000 °C. At this temperature, a series of complex and orderly chemical reactions will occur between the calcium carbonate salt and various components in the fly ash, such as silicate, aluminate, etc. These reactions not only promote the decomposition and reconstruction of the calcium carbonate salt, but also lead to a significant change in the original structure of the fly ash, thereby generating a mixture in the shape of a porous structure. The formation of this porous structure significantly increases the surface area of the fly ash, enabling its surface to adsorb and accommodate more moisture and other substances. Secondly, there are a large number of tiny channels and sites inside the porous structure. These channels and sites are like miniature "water absorption pipes", providing more penetration paths and storage spaces for moisture, thus greatly improving the water absorption of the fly ash. This change is of great significance for enhancing the water absorption rate of the bricks, improving their wetting performance and durability.

[0067] However, if the roasting temperature is too low, it will directly affect the rate and extent of the chemical reaction. Under the condition of lower than 800 °C, the decomposition of the calcium carbonate salt and the structural transformation of the fly ash may not proceed sufficiently, resulting in an incomplete formation of the porous structure, and may even maintain the original dense structure. This will limit the increase in the surface area of the fly ash and the formation of water absorption channels, thereby reducing its water absorption.

[0068] On the contrary, if the calcination temperature is too high, exceeding 1000 °C, although theoretically it can accelerate chemical reactions, the too high temperature may also bring a series of adverse effects. First of all, the too high temperature may cause some components in the fly ash to undergo excessive melting or volatilization, destroying its original porous structure. Secondly, the high temperature may also trigger unnecessary energy consumption and environmental pollution problems, increasing production costs. Most importantly, the too high temperature may make the porous structure unstable, even generate cracks and breakages, seriously affecting the water absorption and overall performance of the fly ash.

[0069] As an optional embodiment of the present invention, in step S1, the mass ratio of the alkaline activator, white mud and water is (2-3):1:(5-8), such as 2:1:5, 2:1:6, 2:1:7, 3:1:5, 3:1:6, 3:1:7, 2.5:1:5, 2.5:1:6, 2.5:1:7, etc.

[0070] Specifically, the addition of the alkaline activator is to activate the potential reaction activity in the white mud, so that the silicate components therein can be fully released and transformed. The mass ratio of the alkaline activator is controlled within (2-3) parts. The selection of this range can not only ensure the effective neutralization of the acidic substances in the white mud, but also avoid adverse reactions caused by excessive alkalinity, such as the destruction of the silicate structure or unnecessary side reactions. By precisely controlling the dosage of the alkaline activator, the present invention realizes the effective activation and transformation of the silicate components in the white mud, providing a good chemical environment for subsequent reactions.

[0071] Secondly, as the core raw material of the present invention, the mass ratio of the white mud is fixed at 1 part. This setting ensures the stability and consistency of the silicate components in the reaction system, laying a foundation for generating high-quality silicate wet mud. The oxide components such as SiO2 and Al2O3 in the white mud are dissolved and transformed under the action of the alkaline activator to form a stable silicate structure, providing a necessary chemical basis for subsequent mixing with fly ash and carbonization reaction.

[0072] Finally, the mass ratio of water is controlled within (5-8) parts. As a solvent and reaction medium, water not only promotes the uniform distribution of the alkaline activator in the white mud, but also participates in the dissolution and transformation process of the silicate components. By precisely controlling the dosage of water, the present invention ensures the fluidity and uniformity of the reaction system, avoiding problems of uneven mixing or insufficient reaction caused by too much or too little water. At the same time, an appropriate amount of water also helps the dispersion of the silicate wet mud and the progress of the carbonization reaction during the subsequent ball milling process.

[0073] As an optional embodiment of the present invention, in step S3, the mass ratio of the mixed wet mud to the fly ash is 1:(1-3), such as 1:1.5, 1:2, 1:2.5, etc.

[0074] Specifically, the present invention defines the mass ratio of the mixed wet mud to fly ash as 1:(1 - 3), which not only ensures the sufficiency of silicate components in the mixed materials but also fully considers the influence of the addition amount of fly ash on its structure and performance. The selection of this ratio enables the mixed materials to form a stable and porous structure during subsequent ball milling, carbonization reaction, and high-temperature roasting processes, thereby significantly improving the water absorption and overall performance of the materials.

[0075] According to the second aspect of the present invention, there is provided a high-strength water-absorbing material prepared by the preparation method of the high-strength water-absorbing material as described above.

[0076] According to the third aspect of the present invention, there is provided a high-strength water-absorbing material prepared by the preparation method of the high-strength water-absorbing material as described above or the application of the high-strength water-absorbing material as described above, which can be used for preparing permeable bricks.

[0077] As an optional implementation manner of the present invention, the preparation method of the permeable brick includes the following steps:

[0078] (1) Stir and mix the high-strength water-absorbing material and the aggregate, and then add water and continue to stir to obtain the raw material for the permeable brick.

[0079] (2) Place the raw material for the permeable brick in a mold and press it to obtain a brick blank.

[0080] (3) Perform autoclave curing on the brick blank to obtain the permeable brick.

[0081] As an optional implementation manner of the present invention, the aggregate includes cement, slag, and metakaolin.

[0082] As an optional implementation manner of the present invention, the mass ratio of the high-strength water-absorbing material to the aggregate is 1:(1 - 3), such as 1:1.5, 1:2, 1:2.5, etc.

[0083] As an optional implementation manner of the present invention, the conditions for autoclave curing include:

[0084] The temperature is 180 - 200 °C (such as 185 °C, 190 °C, 195 °C, etc.); the pressure is 0.8 - 1.2 MPa (such as 0.9 MPa, 1 MPa, 1.1 MPa, etc.); the time is 6 - 8 h (such as 6.5 h, 7 h, 7.5 h, etc.).

[0085] Specifically, autoclave curing is a method of curing brick blanks in a high-temperature and high-pressure steam environment. It helps to accelerate the hydration reaction of the aggregates inside the brick blanks and promotes the further conversion and solidification of unreacted components such as silicates in high-strength water-absorbing materials, thereby improving the strength and durability of permeable bricks. During autoclave curing, we strictly control the temperature, pressure, and curing time of the steam to ensure that the permeable bricks can fully absorb the moisture and heat in the steam and achieve the best curing effect. After autoclave curing, the permeable bricks not only have high strength and excellent water absorption, but also possess good freeze-thaw resistance, wear resistance, weather resistance and other properties, and can meet the use requirements under various complex environments.

[0086] Among them, it should be noted that too high a temperature may cause excessive pores or cracks inside the permeable bricks, affecting their overall performance; while too low a temperature may make the curing process insufficient, resulting in insufficient strength of the permeable bricks; appropriate pressure can also help the permeable bricks maintain a certain shape and dimensional stability during the curing process, preventing them from deforming or cracking due to excessive internal stress; the length of the curing time will directly affect the degree of completion of the chemical reaction inside the permeable bricks and the solidification effect. Too short a curing time may lead to insufficient cement hydration reaction inside the permeable bricks, thus affecting their strength and durability; while too long a curing time may increase production costs and reduce production efficiency.

[0087] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0088] Example 1

[0089] S1: Put calcium hydroxide, white mud and water into a magnetic stirring reactor, heat and stir at a stirring rate of 450 r / min at a temperature of 130 °C for 1.5 h. Stop stirring when the temperature cools to 55 °C to obtain a hydrated mixture;

[0090] Among them, the mass ratio of calcium hydroxide, white mud and water is 2:1:8;

[0091] S2: Filter the hydrated mixture with gauze to obtain a mixed wet mud;

[0092] Among them, the water content of the mixed wet mud is 55%;

[0093] S3: Put the mixed wet mud and fly ash into a wet ball mill and ball mill at a ball milling rate of 200 r / min for 5 h. The ball milling medium is water; after ball milling, bake at a temperature of 900 °C for 3 h to obtain a high-strength water-absorbing material.

[0094] Among them, the mass ratio of zirconia balls to the total mass of the mixed wet mud and fly ash is 2:1;

[0095] The mass ratio of the mixed wet mud to the fly ash is 1:2.

[0096] Example 2

[0097] S1: Place calcium carbonate, white mud and water in a magnetic stirring reactor, and under the condition of a temperature of 120 °C, carry out heating and stirring at a stirring rate of 500 r / min for 2 h. When the temperature cools to 60 °C, stop stirring to obtain a hydrated mixture;

[0098] Among them, the mass ratio of calcium carbonate, white mud and water is 3:1:6;

[0099] S2: Filter the hydrated mixture with gauze to obtain mixed wet mud;

[0100] Among them, the water content of the mixed wet mud is 50%;

[0101] S3: Place the mixed wet mud and fly ash in a wet ball mill, and carry out ball milling at a ball milling rate of 300 r / min for 4 h. The ball milling medium is water; after ball milling, carry out roasting at a temperature of 1000 °C for 2.5 h to obtain a high-strength water-absorbing material.

[0102] Among them, the mass ratio of zirconia balls to the total mass of the mixed wet mud and fly ash is 3:1;

[0103] The mass ratio of the mixed wet mud to the fly ash is 1:3.

[0104] Example 3

[0105] S1: Place calcium bicarbonate, white mud and water in a magnetic stirring reactor, and under the condition of a temperature of 140 °C, carry out heating and stirring at a stirring rate of 400 r / min for 1 h. When the temperature cools to 50 °C, stop stirring to obtain a hydrated mixture;

[0106] Among them, the mass ratio of the alkaline activator, white mud and water is 2:1:7;

[0107] S2: Filter the hydrated mixture with gauze to obtain mixed wet mud;

[0108] Among them, the water content of the mixed wet mud is 60%;

[0109] S3: Place the mixed wet mud and fly ash in a wet ball mill, and carry out ball milling at a ball milling rate of 100 r / min for 6 h. The ball milling medium is water; after ball milling, carry out roasting at a temperature of 800 °C for 3 h to obtain a high-strength water-absorbing material.

[0110] Among them, the mass ratio of zirconia balls to the total mass of the mixed wet mud and fly ash is 2:1;

[0111] The mass ratio of the mixed wet mud to fly ash is 1:3.

[0112] Comparative Example 1

[0113] The difference between this comparative example and Example 1 is that the alkaline activator is sodium hydroxide, and the rest of the technical parameters and operation steps are the same as those in Example 1.

[0114] Comparative Example 2

[0115] The difference between this comparative example and Example 1 is that calcium hydroxide, white mud, water and fly ash are directly mixed, specifically including:

[0116] S1: Put calcium hydroxide, white mud, water and fly ash into a magnetic stirring reaction kettle, and under the condition of a temperature of 130 °C, carry out heating and stirring at a stirring rate of 450 r / min for 1.5 h. When the temperature cools to 55 °C, stop stirring to obtain a mixture;

[0117] Among them, the mass ratio of calcium hydroxide, white mud, water and fly ash is 2:1:10:6;

[0118] S2: Filter the mixture with gauze to obtain mixed wet mud;

[0119] Among them, the water content of the mixed wet mud is 55%;

[0120] S3: Put the mixed wet mud into a wet ball mill and carry out ball milling at a ball milling rate of 200 r / min for 5 h, and the ball milling medium is water; after ball milling, carry out roasting at a temperature of 900 °C for 3 h to obtain a high-strength water-absorbing material.

[0121] Among them, the mass ratio of zirconia balls to mixed wet mud is 2:1.

[0122] Comparative Example 3

[0123] The main difference between this comparative example and Example 1 is that in step S2, the water content of the mixed wet mud is 40%, and the rest of the technical parameters and operation steps are the same as those in Example 1.

[0124] Manufacturing Example

[0125] Prepare permeable bricks from the high-strength water-absorbing materials prepared in Examples 1-3 and Comparative Examples 1-3 respectively, and the steps are as follows:

[0126] (1) Stir and mix the above high-strength water-absorbing material, cement, slag and metakaolin, and then add water and continue to stir to obtain the raw material for permeable bricks;

[0127] Among them, the mass ratio of the high-strength water-absorbing material to the total mass of cement, slag and metakaolin is 1:(1-3)

[0128] (2) Place the raw materials of the permeable brick in a mold for pressing to obtain a brick blank;

[0129] (3) Steam-cure the brick blank at a temperature of 200 °C and a pressure of 1 MPa for 8 h to obtain a permeable brick.

[0130] Performance test

[0131] (1) Compressive strength

[0132] The compressive strength test of the permeable brick is carried out in accordance with the Standard for Evaluation of Concrete Strength GB / T 50107-2010, and tested by a universal testing machine.

[0133] (2) Flexural strength

[0134] The flexural strength test of the permeable brick is carried out in accordance with the Standard for Permeable Pavement Bricks and Panels GB / T 25993-2010, and tested by a universal testing machine.

[0135] (3) Permeability coefficient

[0136] The permeability coefficient test of the permeable brick is carried out in accordance with the Standard for Permeable Pavement Bricks and Panels GB / T 25993-2010, and tested by a permeability coefficient measuring instrument.

[0137] Effect data

[0138] Perform performance tests on the permeable bricks prepared from the high-strength water-absorbing materials prepared in Examples 1-3 and Comparative Examples 1-3 respectively. The effect data are shown in Table 1:

[0139] Table 1

[0140] Compressive strength (MPa) Flexural strength (MPa) Permeability coefficient (cm / s) Example 1 37.7 3.5 0.036 Example 2 36.8 3.3 0.033 Example 3 37.2 3.4 0.035 Comparative example 1 28.4 2.7 0.022 Comparative example 2 35.4 3.1 0.030 Comparative example 3 33.4 3.0 0.029

[0141] According to Table 1, compared with Example 1, in Comparative Example 1, since the alkaline activator used is sodium hydroxide, the generated sodium silicate salt is soluble in water. After filtration, the sodium silicate salt is severely lost. The main component of the prepared water-absorbing material is fly ash. The prepared permeable brick not only has poor mechanical strength but also has a very low permeability coefficient.

[0142] According to Table 1, compared with Example 1, in Comparative Example 2, since calcium hydroxide, white mud, water and fly ash are directly mixed, the generated calcium silicate salt is covered by fly ash, and the carbonation reaction with carbon dioxide is affected, and the amount of generated calcium carbonate salt is small, which not only affects the mechanical properties of the permeable brick but also affects the permeability coefficient.

[0143] As shown in Table 1, compared with Example 1, in Comparative Example 3, since the moisture content of the mixed wet mud in Comparative Example 3 is 40%, the contact area and reaction rate between silicate and carbon dioxide are significantly reduced, further affecting the formation of calcium carbonate salt, and ultimately resulting in a decrease in the mechanical properties and water permeability coefficient of the permeable brick.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. And these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a high-strength water-absorbing material, characterized in that, It includes the following steps: S1: Stir and mix an alkaline activator, white mud and water to obtain a hydrated mixture; S2: Filter the hydrated mixture to obtain a mixed wet mud; S3: Ball mill the mixed wet mud and fly ash, and perform calcination after ball milling to obtain a high-strength water-absorbing material.

2. The preparation method of the high-strength water-absorbing material according to claim 1, characterized in that, In step S1, the stirring and mixing specifically includes the following steps: Place the alkaline activator, white mud and water in a reaction kettle, and under the condition of a temperature of 120 - 140 °C, carry out heating and stirring at a stirring rate of 400 - 500 r / min for 1 - 2 h. When the temperature cools to 50 - 60 °C, stop stirring; And / or, the reaction kettle is a magnetic stirring reaction kettle; The alkaline activator includes one or more of calcium hydroxide, calcium carbonate, and calcium bicarbonate.

3. The preparation method of the high-strength water-absorbing material according to claim 1, characterized in that, In step S2, the filtration means filtering the hydrated mixture with a gauze to obtain a mixed wet mud; The water content of the mixed wet mud is 50 - 60%.

4. The preparation method of the high-strength water-absorbing material according to claim 1, characterized in that, In step S3, the conditions for ball milling include: The equipment for ball milling is a wet ball mill; The mass ratio of the balls to the total mass of the mixed wet mud and fly ash is (2 - 3):1; The ball milling time is 4 - 6 h; The ball milling rate is 100 - 300 r / min; The ball milling medium is water.

5. The preparation method of the high-strength water-absorbing material according to claim 1, characterized in that, In step S3, the conditions for calcination are: The temperature is 800 - 1000 °C, and the calcination time is 2 - 3 h.

6. The preparation method of the high-strength water-absorbing material according to claim 1, characterized in that, In step S1, the mass ratio of the alkaline activator, white mud and water is (2 - 3):1:(5 - 8); In step S3, the mass ratio of the mixed wet mud to fly ash is 1:(1 - 3).

7. A high-strength water-absorbing material prepared by the preparation method of the high-strength water-absorbing material according to any one of claims 1 - 6.

8. Use of a high-strength water-absorbing material prepared by the method for preparing a high-strength water-absorbing material according to any one of claims 1-6, or a high-strength water-absorbing material according to claim 7, characterized in that It can be used for preparing permeable bricks.

9. The application of the high-strength water-absorbing material according to claim 8, characterized in that, The preparation method of the permeable brick includes the following steps: (1) Stir and mix the high-strength water-absorbing material and aggregate, and then add water and continue to stir to obtain permeable brick raw materials; (2) Place the permeable brick raw materials in a mold and press them to obtain brick blanks; (3) Perform autoclave curing on the brick blanks to obtain permeable bricks.

10. Use of the high-strength water-absorbing material according to claim 9, characterized in that, The aggregate includes cement, slag and metakaolin; The mass ratio of the high-strength water-absorbing material to the aggregate is 1:(1 - 3); The conditions for autoclave curing include: The temperature is 180 - 200 °C; the pressure is 0.8 - 1.2 MPa; the time is 6 - 8 h.