A cemented microsphere, its preparation method and application

Abstract

The present invention provides a cemented microsphere, a preparation method thereof, and an application. The cemented microsphere provided by the present invention comprises an outer shell layer and a repair core. The outer shell layer is a tightly wrapped fibrous membrane, and the repair core layer comprises a carbonated cementitious material and a carbon dioxide source. When the cemented microsphere is used for carbon dioxide curing and carbonizing products, the system temperature rises, water evaporates, and stress is generated in the inner layer of the product; the fibrous membrane is damaged, and the carbonated cementitious material inside the cemented microsphere reacts with carbon dioxide to generate calcium carbonate crystal nuclei and C-S-H gel with cementing effect, thereby repairing cracks and preventing the product from cracking; the excess carbon dioxide can also react with the carbonated cementitious material inside the product to improve the carbonization degree of the product.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon mineralization reaction products, and relates to a cemented microsphere, a preparation method thereof, and an application, in particular to a cemented microsphere, a preparation method thereof, a product for carbon mineralization reaction, and an application. Background Art

[0002] In recent years, technologies and researches on carbon dioxide absorption, capture, and utilization have been increasing; in the construction industry, materials rich in calcium silicate phase or calcium hydroxide components can form carbonized products with calcite structure under carbon dioxide carbonation curing. For example, Chinese Patent CN114163205 discloses a method for preparing building materials by adding slag and reinforcing agent solution to steel slag; Chinese Patent CN115108784 discloses a thiourea slag carbonized brick and a preparation method thereof, by mixing thiourea slag, carbonized cementitious material, compounding ingredients, and aggregate, adding an admixture or aqueous solution, and forming and curing by carbonization after pressing, the strength above MU10 can be achieved; Chinese Patent CN113998933 discloses a calcium silicate board and a preparation method thereof, by adding iron oxide green to dicalcium silicate and carbonizing in a vacuum CO2 environment to form a high-strength calcium silicate board. However, the carbonization reaction is an exothermic reaction, and a large amount of heat will be released during the curing process, causing the temperature in the system to rise, and then causing the surface moisture to evaporate. When the surface moisture content drops below the saturation point, the surface layer of the product begins to shrink, but at this time, the water content in the inner layer of the product is still above the saturation level. The shrinkage of the surface layer of the product is restricted by the inner layer and cannot shrink freely, so stress is generated inside the product, the surface layer is in tension, and the inner layer is in compression, which further causes the product to crack. Moreover, after carbon dioxide reacts with the carbonized cementitious material, the generated calcium carbonate will hinder the further entry of carbon dioxide, and the inner cementitious material is difficult to carbonize, resulting in a decrease in the mechanical strength of the product.

[0003] Although there are also some technical solutions for corresponding research, such as Chinese Patent CN112645736 uses modified silica microspheres and modified composite fibers in combination, so that the modified silica microspheres adhere to the surface of the modified composite fibers. Due to the good connection performance between the modified composite fibers and cement, the lightweight concrete has good crack resistance, but the modified silica microspheres can only be applied to the hydration reaction of cast concrete, which has certain limitations.

[0004] Therefore, how to find a more suitable way to solve the problems of product cracking and insufficient carbonization degree in the above-mentioned prior art carbonization reaction, and the current situation of relatively scarce solution means has become one of the focuses widely concerned by many front-line researchers and R & D technology enterprises in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a cemented microsphere and a preparation method thereof. The cemented microsphere provided by the present invention can solve the problems of cracking and low carbonization degree of carbon mineralization reaction products during carbonation curing, and has low production cost, simple process and mild conditions, which is conducive to realizing industrial-scale production and application.

[0006] The present invention provides a cemented microsphere, which comprises a fiber membrane and a carbonized cementitious material and a carbon dioxide source wrapped in the fiber membrane.

[0007] Preferably, the cemented microsphere has a core-shell structure;

[0008] The cemented microsphere has a fiber membrane as the shell layer and a carbonized cementitious material and a carbon dioxide source as the core;

[0009] The thickness of the fiber membrane is 200-600 μm;

[0010] The particle size of the cemented microsphere is 1-5 mm.

[0011] Preferably, the mass ratio of the fiber membrane to the carbonized cementitious material is (1-5):(100-200);

[0012] The mass ratio of the carbonized cementitious material to the carbon dioxide source is (5-15):1;

[0013] The fiber membrane is a dense fiber membrane;

[0014] The material of the fiber membrane includes one or more of polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose and polyacrylamide.

[0015] Preferably, the carbonized cementitious material includes a material rich in calcium silicate phase and / or a material rich in calcium hydroxide;

[0016] The material rich in calcium silicate phase includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, calcium silicate monohydrate and tricalcium disilicate;

[0017] The material rich in calcium hydroxide includes one or more of red mud, carbide slag and thiourea slag;

[0018] The carbon dioxide source includes dry ice and / or a capsule containing carbon dioxide gas;

[0019] The carbon dioxide-containing gas includes carbon dioxide-containing industrial tail gas;

[0020] The carbon dioxide-containing industrial tail gas includes one or more of thermal power plant tail gas, rubber factory tail gas, kiln tail gas, cement factory tail gas, paint factory tail gas and thiourea tail gas;

[0021] The shell composition of the capsule includes gelatin and glycerol.

[0022] The present invention provides a method for preparing cemented microspheres, comprising the following steps:

[0023] 1) Mix the carbonized cementitious material with a carbon dioxide source at low temperature to obtain a mixture;

[0024] 2) Place the mixture obtained in the above step in a cellulose solution to allow the cellulose to wrap the mixture, obtaining cemented microspheres.

[0025] Preferably, the low-temperature mixing method includes low-temperature slow stirring and mixing;

[0026] The rate of the low-temperature mixing is 30-60 rpm;

[0027] The temperature of the low-temperature mixing is -50 to 20 °C;

[0028] The time of the low-temperature mixing is 1-10 min.

[0029] Preferably, the mass ratio of the carbonized cementitious material to the carbon dioxide source is (5-15):1;

[0030] The time of being placed is 1-20 min.

[0031] The present invention provides an article for carbon mineralization reaction, comprising the cemented microspheres described in any one of the above technical solutions or the cemented microspheres prepared by the preparation method described in any one of the above technical solutions.

[0032] Preferably, the article further includes a matrix material and water;

[0033] The matrix material includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, tricalcium silicate, slag, carbide slag, thiourea slag, quartz sand tailings, and fly ash;

[0034] In the article, the mass content of the matrix material is 50%-80%;

[0035] In the article, the mass content of the cemented microspheres is 5%-30%;

[0036] In the article, the mass content of water is 8%-20%;

[0037] The article is obtained by mixing the cemented microspheres, the matrix material and water and then pressing;

[0038] The pressure of the pressing is 5-30 MPa.

[0039] The present invention also provides the application of the cementitious microspheres described in any one of the above technical solutions, the cementitious microspheres prepared by the preparation method described in any one of the above technical solutions, or the products described in any one of the above technical solutions in the carbonation curing in the building materials field.

[0040] The present invention provides a cementitious microsphere, which includes a fiber membrane and a carbonated cementitious material and a carbon dioxide source wrapped inside the fiber membrane. Compared with the prior art, the present invention provides a cementitious microsphere with a specific structure and composition, including an outer shell layer and a repair inner core. The outer shell layer is a tightly wrapped fiber membrane, and the repair inner layer includes a carbonated cementitious material and a carbon dioxide source. When carbon dioxide cures and carbonates the product, the system temperature rises, moisture evaporates, and stress is generated inside the product; the fiber membrane is damaged, and the carbonated cementitious material and carbon dioxide inside the cementitious microsphere react to generate calcium carbonate nuclei and C-S-H gel with cementitious effect, thereby repairing cracks and preventing the product from cracking; the excess carbon dioxide can also react with the carbonated cementitious material inside the product to increase the carbonation degree of the product.

[0041] When the cementitious microspheres provided by the present invention are applied to carbonation curing, the carbonation reaction releases heat, causing the system temperature to rise. The dry ice particles are vaporized by heat to form carbon dioxide gas, which fills the inside of the microspheres; as the temperature rises, the surface moisture of the product is evaporated by heat. When the surface moisture content drops below the saturation point, the surface layer of the product begins to shrink. However, at this time, the water content of the adjacent inner layer of the product is still above the saturation level and does not shrink. The shrinkage of the surface layer of the product is restricted by the inner layer and cannot shrink freely. Therefore, stress is generated inside the product, which in turn causes the product to crack. The carbon dioxide filling the inside of the microspheres exerts an outward expansion pressure on the fiber membrane; after the fiber membrane is subjected to the tensile force of the outer crack and the outward pressure, it ruptures. At the same time, carbon dioxide reacts with the cementitious material in the repair layer of the cementitious microsphere to generate calcite that acts as a nucleus and C-S-H gel with a bonding effect, thereby repairing the cracks. In addition, each cementitious microsphere can also serve as a "small supply station" for the carbonation reaction. After the excess carbon dioxide reacts with the carbonated cementitious material inside the cementitious microsphere, it continues to diffuse and further reacts with the carbonated cementitious material inside the carbonated product outside the cementitious microsphere to increase the carbonation degree of the product.

[0042] For the cementitious microspheres provided by the present invention, the calcium carbonate and C-S-H generated by the reaction of the fiber membrane and the carbonated cementitious material on the outer shell layer of the cementitious microsphere play the roles of crystal nucleus, connection and bonding, and can effectively repair the cracks generated during the carbonation process curing; and the carbon dioxide inside the cementitious microsphere can further react with the cementitious material in the product, increasing the carbonation degree of the product, thereby improving the mechanical properties of the prepared product. Moreover, the production cost is low, the process is simple, and the conditions are mild, which is conducive to realizing industrial-scale production and application.

[0043] The experimental results show that for the building materials products formed by carbonization using the cementitious microspheres provided by the present invention, the compressive strength and the degree of carbonization are significantly improved. The maximum increases are 17.15 MPa and 5.55% respectively, and the performance is improved by about 27%. However, when only adding the cementitious microspheres to the cementitious material without adding dry ice, the performance is not significantly improved. At the same time, changing the type of carbonized cementitious material and its ratio to the carbon dioxide source also helps to improve the compressive strength and the degree of carbonization. Description of the Drawings

[0044] Figure 1 It is a schematic diagram of the reaction mechanism of the cementitious microspheres provided by the present invention during carbonization curing. Detailed Embodiments

[0045] To further understand the present invention, the preferred implementation schemes of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the invention.

[0046] For all raw materials of the present invention, there is no special limitation on their sources, and they can be purchased on the market or prepared by conventional methods well-known to those skilled in the art.

[0047] For all raw materials of the present invention, there is no special limitation on their purity. The present invention preferably uses industrial purity or the conventional purity requirements in the field of preparing carbon mineralization reaction products.

[0048] For all raw materials of the present invention, their grades and abbreviations are all conventional grades and abbreviations in the art. Each grade and abbreviation is clear and definite in the field of its related uses. Those skilled in the art can purchase or prepare them by conventional methods according to the grade, abbreviation and corresponding uses.

[0049] The present invention provides a kind of cementitious microspheres, and the cementitious microspheres include a fiber membrane and a carbonized cementitious material and a carbon dioxide source wrapped inside the fiber membrane.

[0050] In the present invention, the cementitious microspheres preferably have a core-shell structure.

[0051] In the present invention, the cementitious microspheres preferably use the fiber membrane as the shell layer and the carbonized cementitious material and the carbon dioxide source as the inner core.

[0052] In the present invention, the thickness of the fiber membrane is preferably 200 - 600 μm, more preferably 250 - 550 μm, more preferably 300 - 500 μm, and more preferably 350 - 450 μm.

[0053] In the present invention, the particle size of the cementitious microspheres is preferably 1 - 5 mm, more preferably 1.5 - 4.5 mm, more preferably 2 - 4 mm, and more preferably 2.5 - 3.5 mm.

[0054] In the present invention, the mass ratio of the fiber membrane to the carbonized cementitious material is preferably (1-5):(100-200), more preferably (2-4):(100-200), and even more preferably (1-5):(140-160).

[0055] In the present invention, the mass ratio of the carbonized cementitious material to the carbon dioxide source is preferably (5-15):1, more preferably (7-13):1, and even more preferably (9-11):1.

[0056] In the present invention, the fiber membrane is preferably a dense fiber membrane.

[0057] In the present invention, the material of the fiber membrane preferably includes one or more of polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, and polyacrylamide, and more preferably is polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, or polyacrylamide.

[0058] In the present invention, the carbonized cementitious material preferably includes a material rich in calcium silicate phase and / or rich in calcium hydroxide, and more preferably is a material rich in calcium silicate phase or rich in calcium hydroxide.

[0059] In the present invention, the material rich in calcium silicate phase preferably includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, calcium silicate monohydrate, and tricalcium disilicate, and more preferably is steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, calcium silicate monohydrate, or tricalcium disilicate.

[0060] In the present invention, the material rich in calcium hydroxide preferably includes one or more of red mud, carbide slag, and thiourea slag, and more preferably is red mud, carbide slag, or thiourea slag.

[0061] In the present invention, the carbon dioxide source preferably includes dry ice and / or capsules containing carbon dioxide gas, and more preferably is dry ice or capsules containing carbon dioxide gas.

[0062] In the present invention, the carbon dioxide gas preferably includes industrial tail gas containing carbon dioxide.

[0063] In the present invention, the industrial tail gas containing carbon dioxide preferably includes one or more of thermal power plant tail gas, rubber factory tail gas, kiln tail gas, cement factory tail gas, paint factory tail gas, and thiourea tail gas, and more preferably is thermal power plant tail gas, rubber factory tail gas, kiln tail gas, cement factory tail gas, paint factory tail gas, or thiourea tail gas.

[0064] In the present invention, the shell component of the capsule preferably includes gelatin and glycerin.

[0065] When the carbon dioxide source used in the present invention is industrial tail gas containing carbon dioxide, the industrial tail gas containing carbon dioxide can be set in a gas capsule, stirred evenly with the carbonized cementitious material, and then placed in a fiber solution for wrapping. The gas capsule will not dissolve when contacting with the cellulose aqueous solution at normal temperature for a short time. When carbonization curing is carried out, after the fiber membrane is heated and ruptured, the water generated by the reaction of the carbonized cementitious material and external carbon dioxide enters the inside of the cementitious microspheres. In addition, as the environmental temperature rises during the carbonization reaction, the gelatin on the outer shell of the gas capsule dissolves in hot water, thereby releasing carbon dioxide gas.

[0066] In order to complete and refine the overall technical solution of the present invention, better ensure the structure, composition and properties of the cementitious microspheres, and better improve the carbonization degree and mechanical properties of the carbon mineralization products, the above-mentioned cementitious microspheres specifically include the following structures:

[0067] A kind of cementitious microsphere, comprising an outer shell layer and a repair layer. The outer shell layer is a tightly wrapped fiber membrane, and the repair layer includes a carbonized cementitious material and a carbon dioxide source.

[0068] Specifically, the tightly wrapped fiber membrane includes one or more of polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, and polyacrylamide.

[0069] Specifically, the carbonized cementitious material is a material rich in calcium silicate phase or calcium hydroxide component.

[0070] Specifically, the material rich in calcium silicate phase components includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, calcium silicate monohydrate, and tricalcium disilicate.

[0071] Specifically, the material rich in calcium hydroxide component includes one or more of red mud, carbide slag, and thiourea slag.

[0072] Specifically, the carbon dioxide source includes dry ice or a gas capsule containing carbon dioxide gas. Among them, the carbon dioxide gas-containing includes industrial tail gas containing carbon dioxide.

[0073] Specifically, the carbon dioxide gas-containing preferably includes industrial tail gas containing carbon dioxide.

[0074] Specifically, the industrial tail gas containing carbon dioxide includes one or more of thermal power plant tail gas, rubber factory tail gas, kiln tail gas, cement factory tail gas, paint factory tail gas, and thiourea tail gas.

[0075] Specifically, the outer shell component of the capsule preferably includes gelatin and glycerin.

[0076] The present invention provides a preparation method of a cementitious microsphere, comprising the following steps:

[0077] 1) Mix the carbonated cementitious material with a carbon dioxide source at low temperature to obtain a mixture;

[0078] 2) Place the mixture obtained in the above step in a cellulose solution so that the cellulose wraps the mixture to obtain cemented microspheres.

[0079] In the present invention, first, the carbonated cementitious material is mixed with a carbon dioxide source at low temperature to obtain a mixture.

[0080] In the present invention, the method of low-temperature mixing preferably includes low-temperature slow stirring and mixing.

[0081] In the present invention, the rate of the low-temperature mixing is preferably 30 - 60 rpm, more preferably 35 - 55 rpm, and even more preferably 40 - 50 rpm.

[0082] In the present invention, the temperature of the low-temperature mixing is preferably -50 to 20 °C, more preferably -40 to 10 °C, even more preferably -30 to 0 °C, and even more preferably -20 to -10 °C.

[0083] In the present invention, the time of the low-temperature mixing is preferably 1 - 10 min, more preferably 3 - 8 min, and even more preferably 5 - 6 min.

[0084] In the present invention, the mass ratio of the carbonated cementitious material to the carbon dioxide source is preferably (5 - 15):1, more preferably (7 - 13):1, and even more preferably (9 - 11):1.

[0085] Finally, in the present invention, the mixture obtained in the above step is placed in a cellulose solution so that the cellulose wraps the mixture to obtain cemented microspheres.

[0086] In the present invention, the time of placement is preferably 1 - 20 min, more preferably 3 - 18 min, even more preferably 5 - 15 min, and even more preferably 8 - 12 min.

[0087] In order to complete and refine the overall technical solution of the present invention, better ensure the structure, composition and properties of the cemented microspheres, and better improve the carbonation degree and mechanical properties of the carbon mineralization products, the preparation method of the above cemented microspheres may specifically include the following steps:

[0088] A preparation method of cemented microspheres, comprising the following steps:

[0089] Mix the carbonated cementitious material with dry ice particles at low temperature and stir slowly to form a mixture of the carbonated cementitious material and dry ice particles;

[0090] Soak the mixture in a cellulose solution so that the cellulose solution completely wraps the mixture of the carbonated cementitious material and dry ice particles, and form a dense fiber film on the surface of the mixture.

[0091] Specifically, in the mixture, the mass ratio of the carbonized cementitious material to dry ice is 5 - 15:1.

[0092] Specifically, for the low-temperature slow stirring, the stirring rate is 30 - 60 rpm, the stirring temperature is -50°C - 20°C, and the stirring time is 1 min - 10 min.

[0093] Specifically, the wrapping time is 1 min - 20 min.

[0094] The present invention provides an article for carbon mineralization reaction (carbon mineralization article), including the cementitious microspheres described in any one of the above technical solutions or the cementitious microspheres prepared by the preparation method described in any one of the above technical solutions.

[0095] In the present invention, the article preferably further includes a matrix material and water.

[0096] In the present invention, the matrix material preferably includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, tricalcium silicate, slag, carbide slag, thiourea slag, quartz sand tailings, and fly ash, and more preferably is steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, tricalcium silicate, slag, carbide slag, thiourea slag, quartz sand tailings or fly ash.

[0097] In the present invention, in the article, the mass content of the matrix material is preferably 50% - 80%, more preferably 55% - 75%, and even more preferably 60% - 70%.

[0098] In the present invention, in the article, the mass content of the cementitious microspheres is preferably 5% - 30%, more preferably 10% - 25%, and even more preferably 15% - 20%.

[0099] In the present invention, in the article, the mass content of water is preferably 8% - 20%, more preferably 10% - 18%, and even more preferably 12% - 16%.

[0100] In the present invention, the article is preferably obtained by pressing after mixing the cementitious microspheres, the matrix material and water.

[0101] In the present invention, the pressure of the pressing is preferably 5 - 30 MPa, more preferably 10 - 25 MPa, and even more preferably 15 - 20 MPa.

[0102] In the present invention, the cementitious microspheres are located everywhere in the carbon mineralization product. During the carbon mineralization reaction, the cementitious microspheres only exist in the uncarbonated region. Specifically, the cementitious microspheres are located in the carbon mineralization product. Along with the carbon mineralization process of the product used for carbon mineralization, the cementitious microspheres are integrated with the carbon mineralization product during the carbon mineralization process, and in the uncarbonated region, there are cementitious microspheres.

[0103] See Figure 1 , Figure 1 which is a schematic diagram of the reaction mechanism of the cementitious microspheres provided by the present invention in carbonation curing. Among them, 1 - carbonated region in the carbonated product, 2 - fiber membrane, 3 - mixture of carbonated cementitious material and dry ice, 4 - uncarbonated region in the carbonated product.

[0104] The present invention provides the application of the cementitious microspheres described in any one of the above technical solutions, the cementitious microspheres prepared by the preparation method described in any one of the above technical solutions, or the product described in any one of the above technical solutions in the aspect of carbonation curing in the building materials field.

[0105] Specifically, the application can be the application in the curing process of carbonated products in the building materials field.

[0106] The above content of the present invention provides a cementitious microsphere, its preparation method, a product for carbon mineralization reaction, and an application. The cementitious microsphere with a specific structure and composition provided by the present invention includes an outer shell layer and a repair inner core. The outer shell layer is a densely wrapped fiber membrane, and the repair inner layer includes a carbonated cementitious material and a carbon dioxide source. When carbonating and curing the carbonated product with carbon dioxide, the system temperature rises, water evaporates, and stress is generated inside the product; the fiber membrane is damaged, and the carbonated cementitious material and carbon dioxide inside the cementitious microsphere react to generate calcium carbonate crystal nuclei and C-S-H gel with cementing effect, thereby repairing cracks and preventing the product from cracking; the excess carbon dioxide can also react with the carbonated cementitious material inside the product to increase the carbonation degree of the product.

[0107] When the cemented microspheres provided by the present invention are applied to carbonation curing, heat is released during the carbonation reaction, causing the system temperature to rise. The dry ice particles are vaporized by heat to form carbon dioxide gas, which fills the interior of the microspheres. As the temperature rises, the surface moisture of the product evaporates. When the surface moisture content drops below the saturation point, the surface layer of the product begins to shrink. However, at this time, the water content of the adjacent inner layer of the product is still above the saturation level and does not shrink. The shrinkage of the product surface layer is restricted by the inner layer and cannot shrink freely, so stress is generated inside the product, which in turn causes cracking of the product. The carbon dioxide filling the interior of the microspheres exerts an outward expansion pressure on the fiber membrane. After the fiber membrane is subjected to the tensile force of the outer crack and the outward pressure, it ruptures. At the same time, carbon dioxide reacts with the gelling material of the cemented microsphere repair layer to generate calcite that acts as a crystal nucleus and C-S-H gel with a binding effect, thereby repairing the crack. In addition, each cemented microsphere can also serve as a "small supply station" for the carbonation reaction. After the excess carbon dioxide reacts with the carbonated gelling material in the cemented microsphere, it continues to diffuse and further reacts with the carbonated gelling material in the carbonated product outside the cemented microsphere, improving the carbonation degree of the product.

[0108] For the cemented microspheres provided by the present invention, the calcium carbonate and C-S-H generated by the reaction of the fiber membrane and the carbonated gelling material in the outer shell layer of the cemented microsphere play the roles of crystal nucleus, connection and bonding, and can effectively repair the cracks generated during the carbonation process curing. The carbon dioxide inside the cemented microspheres can further react with the gelling material in the product, improving the carbonation degree of the product, and then enhancing the mechanical properties of the prepared product. Moreover, the production cost is low, the process is simple, and the conditions are mild, which is conducive to realizing industrial-scale production and application.

[0109] The experimental results show that for the building materials products formed by carbonation using the cemented microspheres provided by the present invention, the compressive strength and carbonation degree are significantly improved, with the highest increases of 17.15 MPa and 5.55% respectively, and the performance is improved by about 27%. However, when only the gelling material is added to the cemented microspheres without adding dry ice, the performance is not significantly improved. At the same time, changing the type of carbonated gelling material and the ratio to the carbon dioxide source also helps to improve the compressive strength and carbonation degree.

[0110] To further illustrate the present invention, the following describes in detail a kind of cemented microspheres provided by the present invention, its preparation method and application in combination with embodiments. However, it should be understood that these embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation methods and specific operation processes are given only to further illustrate the features and advantages of the present invention, rather than a limitation on the claims of the present invention. The protection scope of the present invention is not limited to the following embodiments.

[0111] The sources of the raw materials selected in the examples and comparative examples are the same.

[0112] Example 1 (Different ratios of steel slag to dry ice particles 1)

[0113] A cementitious microsphere, its preparation method and application are as follows:

[0114] Mix 40 parts of steel slag with 4 parts of dry ice particles evenly at a temperature of -10°C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0115] Soak the mixture in a polyvinyl alcohol cellulose solution for 10 minutes to completely wrap the mixture of carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber membrane on the surface of the mixture;

[0116] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres and mix them evenly. Press them into a carbonized product with a size of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, and place it in a carbonization device for carbonization. The carbonization conditions are: carbon dioxide concentration 10%, carbon dioxide pressure 0.2 MPa, carbonization temperature 50°C, and carbonization time 20 h.

[0117] Example 2 (Different ratios of steel slag to dry ice particles 2)

[0118] A cementitious microsphere, its preparation method and application are as follows:

[0119] Mix 40 parts of steel slag with 8 parts of dry ice particles evenly at a temperature of -10°C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0120] Soak the mixture in a polyvinyl alcohol cellulose solution for 10 minutes to completely wrap the mixture of carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber membrane on the surface of the mixture;

[0121] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres and mix them evenly. Press them into a carbonized product with a size of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, and place it in a carbonization device for carbonization. The carbonization conditions are: carbon dioxide concentration 10%, carbon dioxide pressure 0.2 MPa, carbonization temperature 50°C, and carbonization time 20 h.

[0122] Example 3 (Adding ratio of cementitious microspheres 1)

[0123] A cementitious microsphere, its preparation method and application are as follows:

[0124] Mix 40 parts of steel slag with 8 parts of dry ice particles evenly at a temperature of -10°C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0125] Soak the mixture in the polyvinyl alcohol cellulose solution for 10 min to completely wrap the mixture of the carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber film on the surface of the mixture.

[0126] Take 200 parts of steel slag, 48 parts of water, and 22 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, and place it in a carbonization device for carbonization. The carbonization conditions are: carbon dioxide concentration 10%, carbon dioxide pressure 0.2 MPa, carbonization temperature 50 °C, and carbonization time 20 h.

[0127] Example 4 (proportion of cementitious microspheres added 2)

[0128] A cementitious microsphere, its preparation method and application, the steps are as follows:

[0129] Mix 40 parts of steel slag and 8 parts of dry ice particles evenly at a temperature of -10 °C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0130] Soak the mixture in the polyvinyl alcohol cellulose solution for 10 min to completely wrap the mixture of the carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber film on the surface of the mixture.

[0131] Take 200 parts of steel slag, 48 parts of water, and 66 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, and place it in a carbonization device for carbonization. The carbonization conditions are: carbon dioxide concentration 10%, carbon dioxide pressure 0.2 MPa, carbonization temperature 50 °C, and carbonization time 20 h.

[0132] Example 5 (different carbonized cementitious materials 1)

[0133] A cementitious microsphere, its preparation method and application, the steps are as follows:

[0134] Mix 40 parts of γ-C2S and 8 parts of dry ice particles evenly at a temperature of -10 °C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0135] Soak the mixture in the polyvinyl alcohol cellulose solution for 10 min to completely wrap the mixture of the carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber film on the surface of the mixture.

[0136] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0137] Example 6 (Different carbonized cementitious materials 2)

[0138] A kind of cementitious microsphere, its preparation method and application, the steps are as follows:

[0139] Mix 40 parts of carbide slag and 8 parts of dry ice particles evenly at a temperature of -10 °C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0140] Soak the mixture in a polyvinyl alcohol cellulose solution for 10 min to completely wrap the mixture of carbonized cementitious material and dry ice particles with the polyvinyl alcohol cellulose solution, and form a dense fiber membrane on the surface of the mixture;

[0141] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0142] Example 7 (Different fiber membranes)

[0143] Mix 40 parts of carbide slag and 8 parts of dry ice particles evenly at a temperature of -10 °C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and dry ice particles;

[0144] Soak the mixture in a carboxymethyl cellulose solution for 10 min to completely wrap the mixture of carbonized cementitious material and dry ice particles with the carboxymethyl cellulose solution, and form a dense fiber membrane on the surface of the mixture;

[0145] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm × 10 cm × 2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0146] Example 8 (When the carbon dioxide source is a gas)

[0147] Inject carbon dioxide gas into a carbon dioxide gas capsule, mix 40 parts of steel slag and 8 parts of carbon dioxide gas capsules evenly at a temperature of -10 °C and a rotation speed of 30 rpm to form a mixture of carbonized cementitious material and gas capsules;

[0148] Soak the mixture in the polyvinyl alcohol cellulose solution for 10 min to completely wrap the mixture of the carbonized binder material and the gas capsules with the polyvinyl alcohol cellulose solution, and form a dense fiber film on the surface of the mixture.

[0149] Take 200 parts of steel slag, 48 parts of water, and 22 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm×10 cm×2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0150] Comparative Example 1 (without adding cementitious microspheres)

[0151] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm×10 cm×2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0152] Comparative Example 2 (only adding carbonized binder material)

[0153] A cementitious microsphere, its preparation method and application, the steps are as follows:

[0154] Stir 40 parts of steel slag evenly at a temperature of -10 °C and a rotation speed of 30 rpm;

[0155] Soak the steel slag in the polyvinyl alcohol cellulose solution for 10 min to completely wrap the steel slag with the polyvinyl alcohol cellulose solution and form a dense fiber film on the surface;

[0156] Take 200 parts of steel slag, 48 parts of water, and 44 parts of cementitious microspheres, mix them evenly, press them into a carbonized product with dimensions of 10 cm×10 cm×2 cm under a pressure of 20 MPa, place it in a carbonization device for carbonization, and the carbonization conditions are: carbon dioxide concentration of 10%, carbon dioxide pressure of 0.2 MPa, carbonization temperature of 50 °C, and carbonization time of 20 h.

[0157] Performance test

[0158] 1. Compressive strength test

[0159] Use a SANS universal testing machine to test the compressive strength of the sample.

[0160] 2. Carbonization degree test

[0161] After cutting, crushing, and grinding the product, the mass m1 is obtained. It is placed in a muffle furnace and kept at 500 °C for 2 h to obtain the mass m2. Then, it is further calcined at 1000 °C for 2 h, and the mass m3 is weighed. For XRF testing, the percentage contents A of CaO and MgO in the sample are obtained. Through the formula Calculate the carbonation degree of calcium ions, then calculate the carbonation degree of magnesium ions, and add them together to obtain the carbonation degree of this piece of product; then calculate the carbonation degrees of other regions and take the average value.

[0162] The above test results are shown in Table 1. Table 1 shows the performance data of the carbonated products prepared in the examples and comparative examples of the present invention after carbonation.

[0163] Table 1

[0164]

[0165]

[0166] The above provides a detailed introduction to a cementitious microsphere provided by the present invention, its preparation method, a product for carbon mineralization reaction, and its application. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the literal description of the claims, or if they include equivalent structural elements that have no substantial difference from the literal description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A cemented microsphere, characterized in that, The cementitious microspheres include a fibrous membrane and a carbonized cementitious material and a carbon dioxide source encapsulated within the fibrous membrane; The carbon dioxide source includes dry ice and / or capsules containing carbon dioxide gas; The thickness of the fibrous membrane is 200 - 600 μm; The material of the fibrous membrane includes one or more of polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, and polyacrylamide; The carbonized cementitious material includes a material rich in calcium silicate phase and / or a material rich in calcium hydroxide; The material rich in calcium silicate phase includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, tricalcium silicate, and tricalcium disilicate; The material rich in calcium hydroxide includes one or more of red mud, carbide slag, and thiourea slag; 2. The cemented microspheres according to claim 1, wherein The cementitious microspheres have a core-shell structure; The cementitious microspheres have the fibrous membrane as the shell layer and the carbonized cementitious material and the carbon dioxide source as the inner core; The particle size of the cementitious microspheres is 1 - 5 mm; 3. The cemented microspheres according to claim 1, wherein The mass ratio of the fibrous membrane to the carbonized cementitious material is (1 - 5):(100 - 200); The mass ratio of the carbonized cementitious material to the carbon dioxide source is (5 - 15):1; The fibrous membrane is a dense fibrous membrane; 4. The cemented microspheres according to claim 1, characterized in that, The carbon dioxide-containing gas includes industrial tail gas containing carbon dioxide; The industrial tail gas containing carbon dioxide includes one or more of thermal power plant tail gas, rubber factory tail gas, kiln tail gas, cement factory tail gas, paint factory tail gas, and thiourea tail gas; The outer shell component of the capsule includes gelatin and glycerol; 5. A method for preparing the cemented microspheres according to any one of claims 1 to 4, characterized in that, It includes the following steps: 1) Mix the carbonized cementitious material and the carbon dioxide source at low temperature to obtain a mixture; 2) Place the mixture obtained in the above step in a cellulose solution to allow the cellulose to wrap the mixture to obtain cementitious microspheres.

6. The preparation method according to claim 5, characterized in that, The method of low-temperature mixing includes low-temperature slow stirring and mixing; The rate of low-temperature mixing is 30 - 60 rpm; The temperature of low-temperature mixing is -50 - 20 °C; The time of low-temperature mixing is 1 - 10 min; 7. The preparation method according to claim 6, characterized in that, The mass ratio of the carbonized cementitious material to the carbon dioxide source is (5 - 15):1; The placement time is 1 - 20 min; 8. An article for carbon mineralization reaction, characterized in that, It includes the cementitious microspheres described in any one of claims 1 - 4 or the cementitious microspheres prepared by the preparation method described in any one of claims 5 - 7; 9. The article according to claim 8, characterized in that, The product further includes a matrix material and water; The matrix material includes one or more of steel slag, magnesium slag, cement, β-dicalcium silicate, γ-dicalcium silicate, tricalcium silicate, tricalcium disilicate, slag, carbide slag, thiourea slag, quartz sand tailings, and fly ash; In the product, the mass content of the matrix material is 50% - 80%; In the product, the mass content of the cementitious microspheres is 5% - 30%; In the product, the mass content of water is 8% - 20%; The product is obtained by mixing the cementitious microspheres, the matrix material, and water and then pressing; The pressure of pressing is 5 - 30 MPa; 10. Application of the cementitious microspheres described in any one of claims 1 - 4, the cementitious microspheres prepared by the preparation method described in any one of claims 5 - 7, or the product described in any one of claims 8 - 9 in carbonation curing in the building materials field.

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