Concrete admixture as well as preparation method and preparation device thereof

Abstract

The invention relates to the technical field of material preparation, and provides a concrete admixture preparation method, which comprises: mixing carbonate-containing solid waste and a cement-based composite material according to a first preset component to obtain a premix; placing the premix in a carbon-containing gas atmosphere, and applying a mechanical shear force to obtain an intermediate; mixing the intermediate with a curing material according to a second preset component, wherein a solid-phase component is a concrete admixture; according to the scheme, the recycling condition of the carbonate-containing solid waste is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of material preparation, and in particular, relates to a concrete admixture and a preparation method and a preparation device thereof. Background Art

[0002] With the rapid development of my country's economy and the rapid expansion of production activities, the treatment and disposal of carbonate-containing solid waste has become increasingly prominent. Large amounts of carbonate-containing solid waste not only occupy land resources, but also damage the ecological environment. The existing treatment and disposal methods for carbonate-containing solid waste are mainly used as raw materials for the production of building materials. For example, carbonate-containing solid waste is used as aggregate to replace cement in concrete. However, carbonate-containing solid waste only acts as a filler in concrete. Large-scale use will reduce the strength of concrete, which results in the inability of this treatment and disposal method to absorb a large amount of carbonate-containing solid waste. Therefore, there is still a lot of room for improvement in the current recycling of carbonate-containing solid waste. Summary of the invention

[0003] The purpose of the present application is to provide a method and device for preparing a concrete admixture, aiming to improve the recycling of carbonate-containing solid waste.

[0004] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0005] In a first aspect, the present application provides a method for preparing a concrete admixture, the preparation method comprising:

[0006] Mixing carbonate-containing solid waste and cement-based composite material according to the first preset component to obtain a premix;

[0007] placing the premix in a carbon-containing gas atmosphere and applying mechanical shear force to obtain an intermediate;

[0008] The intermediate is mixed with the matured material according to a second preset composition, wherein the solid phase component is the concrete admixture.

[0009] The inventors of the present application have discovered through research that, under the combined action of mechanochemistry and carbonization reaction and by using an appropriate amount of additives, carbonate-containing solid waste can be converted into metastable carbonates. Metastable carbonates have a high reaction activity and can improve the activity index and performance of the product concrete admixture, making it have a high practical value and improving the recycling of carbonate-containing solid waste. Furthermore, since the carbonization product will adhere to the surface of the carbonate-containing solid waste and hinder the carbonization reaction, applying mechanical shear force while the carbonization reaction is taking place can peel off the carbonized surface layer and expose the unreacted inner layer structure. At the same time, it can also reduce the particle size of the carbonate-containing solid waste and cement-based composite materials, promote the carbonization reaction, improve the overall carbonization efficiency, and further promote the recycling of carbonate-containing solid waste.

[0010] Preferably, the cement-based composite material comprises a cement-based material, a regulating agent and a solvent in a first set ratio. Correspondingly, the carbonate-containing solid waste and the cement-based composite material are mixed in the first preset ratio to obtain a premix comprising:

[0011] The carbonate-containing solid waste, the cement-based material, the regulator and the solvent are mixed according to the first set ratio and the first preset components to obtain a premix.

[0012] In this way, mixing carbonate-containing solid waste with cement-based composite materials can, on the one hand, effectively utilize carbonate-containing solid waste, reduce the use of cement, reduce carbon emissions, and promote a circular economy; on the other hand, the internal components of carbonate-containing solid waste can react with cement-based composite materials to generate hydration products, thereby improving the mechanical strength and hardness of subsequent products; and mixing the two according to the first preset component can reasonably control the content and ratio of carbonate-containing solid waste to ensure the performance and safety of subsequent products.

[0013] Preferably, the carbonate-containing solid waste includes granite sludge, granite scraps, marble waste slurry, coral stone, oyster shells, limestone powder, white mud, eggshells, magnesite tailings, phosphate tailings and / or asbestos tailings; and / or,

[0014] The cement-based materials include waste concrete sand powder, steel slag byproduct, cement and / or clinker; and / or,

[0015] The regulating agent includes sodium silicate, potassium silicate, sodium carbonate, sodium bicarbonate, potassium carbonate, aluminum hydroxide, polyacrylamide, triethanolamine, polyacrylic acid and / or polycarboxylate.

[0016] In this way, the present application can be applied to a variety of substances, with a wider range of choices in material selection, and by adopting a regulating agent, the crystal type and crystal morphology of the product can be directionally controlled in the subsequent reaction process, mainly regulating the crystal type and morphology of calcium carbonate to adjust the performance of the subsequent product.

[0017] Preferably, placing the premix in a carbon-containing gas atmosphere and applying mechanical shear force to obtain the intermediate comprises:

[0018] The premix is ​​placed in a preset container, a preset flow rate of carbon-containing gas is introduced, a mechanical shear force is applied, and the premix is ​​reacted under preset conditions to obtain an intermediate.

[0019] In this way, the reaction is carried out in a preset container, which can promote the completion of the reaction with higher efficiency.

[0020] Preferably, the mixing of the intermediate and the matured material according to a second preset component, wherein the solid phase component is the concrete admixture, comprises:

[0021] mixing the intermediate with the cooked material according to a second preset composition to obtain a mixture;

[0022] The mixture is subjected to a solid-liquid separation operation, and the obtained solid phase component is the concrete admixture.

[0023] In this way, adding aging materials to the intermediate can increase the overall activity of the material and help improve the mechanical strength and hardness of the subsequent finished product.

[0024] Preferably, the aging material comprises a volcanic ash material and an activator in a second set ratio. Correspondingly, the intermediate is mixed with the aging material according to a second preset component to obtain a mixture comprising:

[0025] The intermediate, the pozzolanic material and the activator are mixed according to the second set ratio and the second preset composition to obtain a mixture.

[0026] In this way, by controlling the ratio between the components, the mixture can have higher performance.

[0027] Preferably, the pozzolanic material comprises fly ash, blast furnace slag, silica fume, metakaolin and / or calcined clay; and / or,

[0028] The activator includes dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, desulfurized gypsum, phosphogypsum, sodium sulfate, potassium sulfate and / or aluminum sulfate.

[0029] In this way, the present application can be applied to the full utilization of various substances, and has a wider range of choices in material selection.

[0030] Preferably, the solid-liquid separation operation is performed on the mixture to obtain the solid component as the concrete admixture, which comprises:

[0031] The mixture is placed in a solid-liquid separation device for dehydration treatment, and the obtained solid component is the concrete admixture.

[0032] In this way, the concrete admixture obtained through the solid-liquid separation operation can have better portability and scalability.

[0033] In a second aspect, the present application provides a concrete admixture, wherein the concrete admixture is prepared by the preparation method as described in any one of the first aspects above.

[0034] In a third aspect, the present application provides a device for preparing a concrete admixture, the device for preparing a concrete admixture comprising:

[0035] A premixing unit, used for mixing carbonate-containing solid waste and cement-based composite material according to a first preset component to obtain a premix;

[0036] A reaction unit, used for placing the premix in a carbon-containing gas atmosphere to apply mechanical shear force to obtain an intermediate;

[0037] The processing unit is used to mix the intermediate with the matured material according to a second preset component, wherein the solid phase component is the concrete admixture.

[0038] In this way, in the premixing unit, carbonate-containing solid waste and cement-based composite materials are mixed according to the first preset component to obtain a premix; in the reaction unit, the premix is ​​placed in a carbon-containing gas atmosphere and mechanical shear force is applied to obtain an intermediate; the processing unit mixes the intermediate and the matured material according to the second preset component, wherein the solid phase component is a concrete admixture.

[0039] Beneficial effects of this application

[0040] The inventors of the present application have discovered through research that, under the combined action of mechanochemistry and carbonation reaction, the reaction of carbonate-containing solid waste and cement-based composite materials can generate metastable carbonates. Metastable carbonates have high reactivity and can promote hydration reactions, thereby improving the activity index and performance of the product concrete admixture, making it have high practical value and improving the recycling of carbonate-containing solid waste; and some of the reaction products generated by the reaction of carbonate-containing solid waste and cement-based composite materials will form a carbonized surface layer attached to the surface of the carbonate-containing solid waste, resulting in incomplete carbonization reaction. While the carbonization reaction is taking place, applying mechanical shear force can peel off the carbonized surface layer, exposing the unreacted inner layer structure, and at the same time can reduce the particle size of carbonate-containing solid waste and cement-based composite materials, thereby enabling the carbonization reaction to be completed, improving the efficiency of the overall reaction, and further promoting the recycling of carbonate-containing solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 is a flow chart of a method for preparing a concrete admixture provided in an embodiment of the present application;

[0043] Figure 2 It is a thermogravimetric analysis characterization diagram provided in the examples of the present application;

[0044] Figure 3 is a schematic diagram of a device for preparing a concrete admixture provided in an embodiment of the present application;

[0045] Figure 4 It is a structural schematic diagram of a device for preparing a concrete admixture provided in an embodiment of the present application;

[0046] Figure 5 This is one of the electron microscope characterization images of the concrete admixture provided in the embodiment of the present application;

[0047] Figure 6 This is the second electron microscope characterization image of the concrete admixture provided in the examples of the present application. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] For the convenience of description, the descriptions of "first", "second", etc. in the present invention are only set for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various implementation methods can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0051] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0052] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0053] Carbonate-containing solid waste refers to solid waste containing carbonate compounds, among which carbonate is a common chemical substance composed of carbon, oxygen and other elements (such as calcium, magnesium, etc.). Carbonate-containing solid waste mainly comes from industrial production, metallurgy and mineral mining. Common carbonate-containing solid waste includes granite sludge, granite scraps, marble waste slurry, coral stone, oyster shells, limestone powder, white mud, eggshells, magnesite tailings, phosphate tailings, asbestos tailings, etc. Since carbonate, the main component of carbonate-containing solid waste, can dissolve and release carbon dioxide under certain conditions, it may lead to problems such as intensified greenhouse effect and soil acidification. Therefore, large amounts of carbonate-containing solid waste not only occupy land resources, but also pose a great threat to ecological and environmental safety.

[0054] With the rapid development of my country's economy and the rapid expansion of production activities, the amount of carbonate-containing solid waste piled up has increased year by year, and its treatment and disposal problem has become increasingly severe. At present, the treatment and disposal methods for carbonate-containing solid waste at home and abroad include: replacing limestone ingredients to calcine cement clinker, used to prepare desulfurizers and used as raw materials for the production of building materials, for example, using carbonate-containing solid waste as aggregate to replace cement in concrete. However, carbonate-containing solid waste only plays a filler role in concrete, and a large amount of use will reduce the strength of concrete. Therefore, judging from the current treatment of carbonate-containing solid waste, there is still a lot of room for improvement in the recycling of carbonate-containing solid waste. In this regard, the present application proposes a method for preparing concrete admixtures.

[0055] Figure 1 A flow chart of a method for preparing a concrete admixture provided in an embodiment of the present application is shown.

[0056] Reference Figure 1 The present invention provides a method for preparing a concrete admixture, comprising the following steps:

[0057] Step S100: mixing carbonate-containing solid waste and cement-based composite material according to a first preset component to obtain a premix;

[0058] Step S101: placing the premix in a carbon-containing gas atmosphere and applying mechanical shear force to obtain an intermediate;

[0059] Step S102: mixing the intermediate with the matured material according to a second preset component, wherein the solid phase component is a concrete admixture.

[0060] The inventors of the present application have discovered through research that, under the combined action of mechanochemistry and carbonation reaction, the reaction of carbonate-containing solid waste and cement-based composite materials can generate metastable carbonate Called, which has high reactivity and can promote hydration reaction, thereby improving the activity index and performance of the product concrete admixture, making it have high practical value and improving the recycling of carbonate-containing solid waste; and some of the reaction products generated by the reaction of carbonate-containing solid waste and cement-based composite materials will form a carbonized surface layer attached to the surface of the carbonate-containing solid waste, resulting in incomplete carbonization reaction. While the carbonization reaction is taking place, applying mechanical shear force can peel off the carbonized surface layer, exposing the unreacted inner layer structure, and at the same time can reduce the particle size of carbonate-containing solid waste and cement-based composite materials, thereby enabling the carbonization reaction to be completed, improving the efficiency of the overall reaction, and further promoting the recycling of carbonate-containing solid waste.

[0061] It should be noted that the hydration reaction mainly refers to the reaction process in which mineral compounds in cement (such as tricalcium silicate, etc.) react chemically under the action of water to form hydration products. Through this process, the hydration products generated by the reaction of silicates and aluminates and other major minerals in cement with water molecules continuously absorb water, expand, crystallize and increase the volume of the rock, so that the particles of the concrete are closely combined with each other, promoting the gradual consolidation and hardening of the concrete, gradually reducing its volume, and showing a certain mechanical strength and hardness.

[0062] It should be noted that metastable carbonates mainly include amorphous calcium carbonate, vaterite and aragonite.

[0063] The step S100 is explained in detail below.

[0064] In step S100, carbonate-containing solid waste and cement-based composite material need to be mixed according to a first preset component to obtain a premix.

[0065] Specifically, carbonate-containing solid wastes include granite sludge, granite scraps, marble waste slurry, coral stone, oyster shells, limestone powder, white mud, eggshells, magnesite tailings, phosphate tailings and / or asbestos tailings.

[0066] The first preset component is embodied in mass ratio as follows:

[0067] Carbonate-containing solid waste: cement-based composite materials = (80-100): (0-20)

[0068] As an example, the specific value of the first preset component may include:

[0069] Carbonate-containing solid waste: cement-based composite material = 80:20,

[0070] Carbonate-containing solid waste: cement-based composite material = 85:15,

[0071] Carbonate-containing solid waste: cement-based composite materials = 90:00 or

[0072] Carbonate-containing solid waste: cement-based composite material = 95:5.

[0073] It should be noted that the above specific numerical values ​​are only examples and are not limiting. This application does not elaborate on other numerical values ​​within the corresponding ranges.

[0074] In the above example, mixing carbonate-containing solid waste with cement-based composite materials can, on the one hand, effectively utilize carbonate-containing solid waste, reduce the use of cement, reduce carbon emissions, and promote a circular economy; on the other hand, the internal components of carbonate-containing solid waste can react with cement-based composite materials to generate hydration products, thereby improving the mechanical strength and hardness of subsequent products; and mixing the two according to the first preset component can reasonably control the content and ratio of carbonate-containing solid waste to ensure the performance and safety of subsequent products.

[0075] As an example, the cement-based composite material includes a cement-based material, a regulator and a solvent in a first set ratio. Correspondingly, to prepare a premix, it is necessary to mix carbonate solid waste, cement-based material, a regulator and a solvent according to the first set ratio and the first preset component.

[0076] The first set ratio of cement-based materials, control agents and solvents is as follows according to the mass ratio:

[0077] Cement-based material: regulator: solvent = (0.5-2): (0-0.5): 1

[0078] Cement-based materials include waste concrete sand powder, steel slag byproducts, cement and / or clinker. Among them, waste concrete sand powder is produced in the process of crushing or screening waste concrete; steel slag byproducts are produced in the process of steelmaking; clinker is clay or other raw materials in the silicate industry that are crushed and mixed into a batch material, and then crushed into a powder with a certain particle composition after high-temperature calcination. Cement and clinker mainly include hydrated calcium silicate gel, hydrated calcium silicoaluminate gel, hydrated calcium aluminate, hydrated calcium sulfoaluminate, hydrated calcium ferrate, hydrated calcium ferroaluminate and / or hydrated calcium fluoroaluminate.

[0079] The solvent includes water or deionized water.

[0080] The regulator includes sodium silicate, potassium silicate, sodium carbonate, sodium bicarbonate, potassium carbonate, aluminum hydroxide, polyacrylamide, triethanolamine, polyacrylic acid and / or polycarboxylate. To ensure the effect of the regulator, its molar concentration needs to be controlled between 0 and 0.5 mol / L.

[0081] In the above example, by using a regulating agent, the crystal type and crystal morphology of the product can be directionally controlled in the subsequent reaction process to adjust the performance of the subsequent product.

[0082] It should be noted that in order to control the fluidity of the premix formed by mixing carbonate-containing solid waste with cement-based composite materials so as to facilitate the smooth reaction, the liquid-solid ratio of the premix needs to be controlled between (0.5:1) and (2:1).

[0083] The step S101 is explained in detail below.

[0084] In step S101, in order to complete the reaction and obtain the intermediate, the premix prepared in step S100 needs to be placed in a carbon-containing gas atmosphere and mechanical shear force is applied. In a possible embodiment, the process may specifically include: placing the premix in a preset container, introducing a preset flow rate of carbon-containing gas, and applying mechanical shear force, and reacting under preset conditions to obtain the intermediate.

[0085] The preset container can be an internal reaction chamber of the device for applying mechanical shear force, or it can be an external container. The device for applying mechanical shear force includes a ball mill, a rod mill, an autogenous mill, and a stirring tank with a stirring effect. In order to ensure the reaction efficiency, certain requirements are required for the working performance of the device for applying mechanical shear force, that is, the mechanical stirring speed is 100 to 1000 rpm, and the specific speed value includes but is not limited to 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000 rpm.

[0086] The carbon-containing gas may be carbon dioxide or industrial waste gas containing carbon dioxide, and the source of the industrial waste gas includes but is not limited to the steel industry, cement industry, electric power industry, chemical industry, non-steel metal products industry, glass or ceramic industry. To ensure the reaction efficiency, the content of carbon dioxide in the industrial waste gas must be no less than 5%, and the preset flow rate of the carbon-containing gas is 0.01-0.5 L / min / g solid, and the specific preset flow rate values ​​include but are not limited to 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5 L / min / g.

[0087] In order to smoothly react to obtain the intermediate and improve the reaction efficiency, preset conditions need to be set, that is, the reaction temperature is set to 20-95°C and the reaction time is set to 5-120min. The specific reaction temperature numerical values ​​include but are not limited to 20, 30, 40, 50, 60, 70, 80, 90 or 95°C, and the specific reaction time numerical values ​​include but are not limited to 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 or 120min.

[0088] As an example, step S101 may specifically include: placing the premix in a ball mill, introducing carbon dioxide at a preset flow rate of 0.05 L / min / g solid, reacting at 55° C. for 70 minutes at a stirring speed of 600 rpm to obtain an intermediate.

[0089] It should be noted that the reaction principles specifically involved in step S101 include:

[0090] CaCO3+CO2(excess)+H2O→Ca(HCO3)2#(1)

[0091] C3S+6CO2(excess)→2Ca(HCO3)2+SiO2#(2)

[0092] C2S+4CO2(excess)→2Ca(HCO3)2+SiO2#(3)

[0093] C 1.75 -S-H+3.5CO2(excess)→1.75Ca(HCO3)2+SiO2+H2O#(4)

[0094] AFt / AFm+CO2(excess)→Ca(HCO3)2+Al(OH)3+CaSO4+H2O#(5)

[0095] C4AF+CO2(excess)→Ca(HCO3)2+Al(OH)3+Fe(OH)3#(6)

[0096] Ca 2+ +CO2CaCO3#(7)

[0097] In step S101, CaCO3 in carbonate-containing solid waste can react with CO2 in the liquid phase to generate a certain amount of Ca(HCO3)2 (as shown in Formula 1), thereby increasing its solubility and improving its reaction activity; in this process, auxiliary materials such as cement-based materials are added to react with CO2 to generate nano-scale CaCO3 and active substances such as silica gel (as shown in Formula 2-6), further improving the reaction activity of carbonate-containing solid waste, promoting hydration reaction, and thus improving the mechanical strength and hardness of subsequent concrete products.

[0098] Figure 2 Thermogravimetric analysis (DTG) characterization diagrams provided in the examples of the present application are shown. Figure 2 Under the combined action of mechanical shear force and carbonation reaction, carbonate-containing solid waste and cement-based composite materials can react to generate metastable carbonates (as shown in Formula 7). Metastable carbonates have high reactivity and can promote hydration reactions, thereby improving the activity index and performance of the product concrete admixture, making it have a higher practical value and improving the recycling of carbonate-containing solid waste.

[0099] In addition, since some reaction products will form a carbonized surface layer attached to the surface of the carbonate-containing solid waste, resulting in incomplete carbonization reaction, the inventors of the present application apply mechanical shear force while the carbonization reaction is taking place, so that the carbonized surface layer can be peeled off and the unreacted inner layer structure is exposed, while reducing the particle size of the carbonate-containing solid waste and the cement-based composite material, prompting the carbonization reaction to be complete, thereby promoting the improvement of product performance.

[0100] In addition, under the action of mechanical shear force, the crystal morphology of some calcium carbonate products will change from calcite to aragonite, thereby further improving the overall reaction activity and having a certain effect on improving the performance of the product.

[0101] In addition, according to data from the International Energy Agency (IEA), my country's overall carbon dioxide emissions increased from 5.407 billion tons in 2005 to 9.809 billion tons in 2019, nearly doubling. To this end, my country proposed in 2020 to strive to peak carbon dioxide emissions before 2030 and strive to achieve the "dual carbon" strategic goal of carbon neutrality before 2060. However, in view of the current status of carbon dioxide emissions in my country, it is difficult to change the energy structure by simply improving efficiency, and it is difficult to meet the urgent needs of China's low-carbon development. Therefore, in order to achieve the "dual carbon" strategic goals as scheduled, it is urgent to develop practical carbon dioxide storage and utilization technologies. In this regard, in the preparation method of concrete admixtures proposed in this application, carbon dioxide is used as a raw material to react with carbonate-containing solid waste, and chemical fixation of carbon dioxide can be achieved, which not only provides a feasible new path for the effective utilization of carbon dioxide, but also is conducive to the achievement of my country's "dual carbon" goals.

[0102] The following is a detailed explanation of step S102.

[0103] As a possible embodiment, in step S102, the intermediate and the matured material are mixed according to the second preset component, wherein the solid phase component is a concrete admixture, which may specifically include:

[0104] Step S200: mixing the intermediate and the cooked material according to a second preset component to obtain a mixture;

[0105] Step S201: performing a solid-liquid separation operation on the mixture, and obtaining a solid phase component as a concrete admixture.

[0106] The second preset composition between the intermediate and the ripening material can be expressed in the form of a mass ratio as follows:

[0107] Intermediate: Ripening material = (60-100): (0-50)

[0108] In order to fully mix the reaction, the mixing time of the intermediate and the matured material is 10 to 120 minutes.

[0109] The addition of the aging material to the intermediate can improve the overall activity of the material and help improve the mechanical strength and hardness of the subsequent concrete product.

[0110] As an example, the mature material specifically includes a volcanic ash material and an activator in a second set ratio. Correspondingly, step S200 specifically may include mixing the intermediate, the volcanic ash material and the activator according to the second set ratio and the second preset component to obtain a mixture.

[0111] Pozzolanic materials include fly ash, blast furnace slag, silica fume, metakaolin and / or calcined clay.

[0112] The activator includes dihydrate gypsum, hemihydrate gypsum, anhydrite, desulfurized gypsum, phosphogypsum, sodium sulfate, potassium sulfate and / or aluminum sulfate.

[0113] The second set ratio between the volcanic ash material and the activator can be expressed in terms of mass ratio as follows:

[0114] Volcanic ash material: activator = (50-100): (0-50)

[0115] In the above example, the addition of volcanic ash materials can enhance the mechanical strength and durability of concrete and improve the crack resistance of concrete, while the activator can promote the hydration reaction during the reaction process, further improve the mechanical properties of concrete and extend its service life.

[0116] In order to improve the transportability of the product, the mixture prepared in step S200 needs to be subjected to a solid-liquid separation operation. As a feasible embodiment, step S201 may specifically include: placing the mixture in a solid-liquid separation device for dehydration treatment, and the obtained solid component is the concrete admixture.

[0117] The solid-liquid separation equipment may include a centrifugal sedimentation machine, a vacuum filter, a plate and frame filter press, etc.

[0118] It should be noted that, in other embodiments of the present application, the concrete admixture obtained by the solid-liquid separation operation may have a water content of 5% to 15%.

[0119] For example, the density of the concrete admixture prepared by the above method is 3.1-3.7 g / cm 3 , particle size is 0.1~100μm, specific surface area is 350~700m 2 / kg.

[0120] Figure 3 A schematic diagram of a concrete admixture preparation device provided in an embodiment of the present application is shown, and the preparation device comprises:

[0121] A premixing unit A is used to mix carbonate-containing solid waste and cement-based composite material according to a first preset component to obtain a premix;

[0122] Reaction unit B, used for placing the premix in a carbon-containing gas atmosphere to apply mechanical shear force to obtain an intermediate;

[0123] The processing unit C is used to mix the intermediate with the matured material according to a second preset component, wherein the solid phase component is a concrete admixture.

[0124] In the premixing unit A, carbonate-containing solid waste and cement-based composite materials are mixed according to a first preset component to obtain a premix, and in the reaction unit B, the premix is ​​placed in a carbon-containing gas atmosphere to apply mechanical shear force to obtain an intermediate, and the intermediate and the matured material are mixed according to a second preset component by the processing unit C, wherein the solid phase component is a concrete admixture. The preparation device provided by the present application can realize batch production of concrete admixtures, which has a high promotion significance.

[0125] Figure 4 The schematic diagram of the structure of a concrete admixture preparation device provided in an embodiment of the present application is shown. Figure 3 It can be seen that the main equipment used in the premixing unit A is the stirring tank A1, which includes a feed port A2 and a discharge port A3; the main equipment used in the reaction unit B includes a delivery pump B1, a mechanical carbonization reactor B2 and a gas flow meter B3; the processing unit C is composed of a processing unit 1 and a processing unit 2, and the main equipment used in the processing unit 1 includes a stirring tank C1 and a delivery pump C2, and the stirring tank C1 includes a feed port C3, and the main equipment used in the processing unit 2 includes a solid-liquid separator C4.

[0126] In actual operation, carbonate-containing solid waste and cement-based composite materials are fed into the stirring tank A1 from the feed port A2 according to the first preset component, the premixture obtained after stirring and mixing enters the reaction unit B from the discharge port A3, the premixture is fed into the mechanical carbonization reactor B2 by the delivery pump B1, and carbon-containing gas B4 is introduced for reaction. The flow rate of the carbon-containing gas is controlled according to the gas flowmeter B3 to ensure the reaction efficiency, the intermediate obtained by the reaction is fed into the stirring tank C1 in the processing unit 1 by the delivery pump B1, and the clinker material is fed into the stirring tank C1 from the feed port C3 according to the second preset component. The mixture obtained after the mixing reaction is fed into the solid-liquid separator C4 in the processing unit 2 by the delivery pump C2 for dehydration treatment, and the obtained solid phase component is the concrete admixture D.

[0127] The following describes the invention in conjunction with specific embodiments.

[0128] Embodiment 1:

[0129] Step 1: using a premixing unit to uniformly mix carbonate-containing solid waste, cement-based materials and water to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 1:1;

[0130] Step 2: mechanically carbonizing the premix using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.02 L / min / g solid, the reaction temperature is 20° C., and the reaction time is 30 min;

[0131] Step 3: The intermediate is mixed evenly with fly ash and aged for 30 minutes, wherein the fly ash accounts for 20% by mass;

[0132] Step 4: Dehydrate the mixture in step 3 using a processing unit to obtain a concrete admixture.

[0133] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0134] Embodiment 2:

[0135] Step 1: prepare a regulating agent solution, wherein the concentration of the sodium silicate solution is 0.1 mol / L;

[0136] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and 0.1 mol / L sodium silicate solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 1:1;

[0137] Step 3: mechanically carbonizing the premix using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.02 L / min / g solid, the reaction temperature is 20° C., and the reaction time is 30 min;

[0138] Step 4: The intermediate is mixed evenly with fly ash and aged for 30 minutes, wherein the fly ash accounts for 20% by mass;

[0139] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0140] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0141] Embodiment 3:

[0142] Step 1: prepare a regulating agent solution, wherein the concentration of the sodium silicate solution is 0.1 mol / L;

[0143] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and 0.1 mol / L sodium silicate solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 2:1;

[0144] Step 3: using a reaction unit to perform mechanical carbonization treatment on the premix to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.02 L / min / g solid, the reaction temperature is 50° C., and the reaction time is 30 min;

[0145] Step 4: The intermediate is mixed evenly with fly ash and desulfurized gypsum, and matured for 60 minutes, wherein the mass ratio of the intermediate: fly ash: desulfurized gypsum is 70:20:10;

[0146] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0147] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0148] Embodiment 4:

[0149] Step 1: prepare a regulator solution, wherein the concentration of sodium carbonate is 0.1 mol / L and the concentration of triethanolamine is 0.05 mol / L;

[0150] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 90:10, and the liquid-solid ratio is 1:2;

[0151] Step 3: using a reaction unit to perform mechanical carbonization treatment on the premix to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.02 L / min / g solid, the reaction temperature is 50° C., and the reaction time is 30 min;

[0152] Step 4: Evenly mix the intermediate, fly ash and desulfurized gypsum, and mature for 30 minutes, wherein the mass ratio of the intermediate: fly ash: desulfurized gypsum is 70:20:10;

[0153] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0154] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0155] Embodiment 5:

[0156] Step 1: prepare a regulator solution, wherein the concentration of triethanolamine is 0.1 mol / L;

[0157] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 90:10, and the liquid-solid ratio is 1:2;

[0158] Step 3: mechanically carbonizing the premix using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.02 L / min / g solid, the reaction temperature is 50° C., and the reaction time is 60 min;

[0159] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 60 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0160] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0161] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0162] Embodiment 6:

[0163] Step 1: prepare a regulating agent solution, wherein the concentration of triethanolamine is 0.1 mol / L and the concentration of sodium silicate is 0.05 mol / L;

[0164] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 80:20, and the liquid-solid ratio is 1:1;

[0165] Step 3: mechanically carbonizing the premix using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 15%, the flow rate is 0.01 L / min / g solid, the reaction temperature is 80° C., and the reaction time is 30 min;

[0166] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 60 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0167] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0168] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0169] Embodiment 7:

[0170] Step 1: prepare a regulating agent solution, wherein the concentration of triethanolamine is 0.05 mol / L, the concentration of sodium silicate is 0.1 mol / L, and the concentration of polyacrylamide is 0.01 mol / L;

[0171] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 1:2;

[0172] Step 3: mechanically carbonizing the premix by using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 20%, the flow rate is 0.05 L / min / g solid, the reaction temperature is 60° C., and the reaction time is 30 min;

[0173] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 30 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0174] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0175] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0176] Embodiment 8:

[0177] Step 1: prepare a regulator solution, wherein the concentration of polyacrylamide is 0.02 mol / L;

[0178] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 90:10, and the liquid-solid ratio is 1:2;

[0179] Step 3: mechanically carbonizing the premix by using a reaction unit to obtain an intermediate, wherein the carbon dioxide content in the industrial tail gas used is 20%, the flow rate is 0.05 L / min / g solid, the reaction temperature is 60° C., and the reaction time is 30 min;

[0180] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 60 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0181] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0182] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0183] Comparative Example 1:

[0184] Step 1: prepare a regulator solution, wherein the concentration of triethanolamine is 0.1 mol / L;

[0185] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 1:2;

[0186] Step 3: using a reaction unit to perform a mechanochemical activation treatment on the premix to obtain an intermediate, wherein the carbon dioxide ventilation volume is 0, the reaction temperature is 60° C., and the reaction time is 30 min;

[0187] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 30 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0188] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0189] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0190] Comparative Example 2:

[0191] Step 1: prepare a regulating agent solution, wherein the concentration of triethanolamine is 0.1 mol / L and the concentration of sodium silicate is 0.1 mol / L;

[0192] Step 2: using a premixing unit to uniformly mix the carbonate-containing solid waste, cement-based materials and the regulating agent solution to obtain a premix, wherein the mass ratio of carbonate-containing solid waste to cement-based materials is 95:5, and the liquid-solid ratio is 1:2;

[0193] Step 3: using a reaction unit to perform a mechanochemical activation treatment on the premix to obtain an intermediate, wherein the carbon dioxide ventilation volume is 0, the reaction temperature is 20° C., and the reaction time is 60 min;

[0194] Step 4: Evenly mix the intermediate with fly ash, blast furnace slag and desulfurized gypsum, and ripen for 30 minutes, wherein the mass ratio of intermediate: fly ash: blast furnace slag: desulfurized gypsum is 70:15:10:5;

[0195] Step 5: Dehydrate the mixture in step 4 using a processing unit to obtain a concrete admixture.

[0196] 20% concrete admixture was uniformly mixed with PO 42.5 cement according to weight percentage, and cement mortar test blocks were prepared according to the method in GB / T17671-2005 "Test method for strength of cement mortar" (ISO method), and the activity index of concrete admixture was calculated according to GB / T12957-2005 "Test method for activity of industrial waste residue used in cement admixtures". The test results are shown in Table 1.

[0197] Referring to Table 1, it can be seen that the activity index of the concrete admixtures corresponding to Examples 1 to 8 at 3 days (3d) and 28 days (28d) is significantly improved compared with the untreated carbonate-containing solid waste and Comparative Examples 1 to 2. At the same time, its 3d activity index is also significantly higher than the activity index of the cement standard sample. The mechanical strength and hardness of the concrete corresponding to the high activity index are also higher. Therefore, the concrete admixture prepared in the present application has better performance.

[0198] Reference Figure 2, in the temperature (Temp.) range of 0 to 1000°C, the thermogravimetric curve of Example 3 is obviously different from that of the untreated carbonate-containing solid waste and Comparative Example 1, and a peak corresponding to metastable carbonate appears, and metastable carbonate has a high reactivity and can improve the activity index of concrete admixtures, which shows that the metastable carbonate generated under the combined action of mechanical shear force and carbonization reaction in the embodiment of the present application has a key promoting effect on improving the activity index of concrete admixtures. It should be noted that if the carbonization reaction is directly carried out without applying mechanical shear force, if metastable carbonate is to be generated during the reaction process to improve the reaction activity, a large amount of additives such as amino acids, magnesium salts and ammonium salts need to be added, and the treatment of the reaction wastewater extended from this is also relatively difficult. The preparation scheme of the present application can avoid this defect.

[0199] Table 1 Activity index of concrete admixtures

[0200]

[0201] Figure 5-6 The electron microscope characterization diagram of the concrete admixture provided in the embodiment of the present application is shown. Figure 5-6 It can be seen that the particle size of the concrete admixture is relatively small, ranging from 0.1 to 100 μm, and can be well integrated with other building materials, and has high practical value. Therefore, the concrete admixture prepared in this application has excellent performance, simple preparation process, easy operation, short time consumption, low energy consumption, significant environmental and economic benefits, and is suitable for large-scale industrial production and utilization.

[0202] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a concrete admixture, characterized in that: The preparation method comprises: Mixing carbonate-containing solid waste and cement-based composite material according to the first preset component to obtain a premix; placing the premix in a carbon-containing gas atmosphere and applying mechanical shear force to obtain an intermediate; The intermediate is mixed with the matured material according to a second preset composition, wherein the solid phase component is the concrete admixture.

2. The method for preparing a concrete admixture according to claim 1, characterized in that: The cement-based composite material comprises a cement-based material, a regulating agent and a solvent in a first set ratio. Correspondingly, the carbonate-containing solid waste and the cement-based composite material are mixed in the first preset ratio to obtain a premix comprising: The carbonate-containing solid waste, the cement-based material, the regulator and the solvent are mixed according to the first set ratio and the first preset components to obtain a premix.

3. The method for preparing a concrete admixture according to claim 2, characterized in that: The carbonate-containing solid waste includes granite sludge, granite scraps, marble waste slurry, coral stone, oyster shells, limestone powder, white mud, eggshells, magnesite tailings, phosphate tailings and / or asbestos tailings; and / or, The cement-based materials include waste concrete sand powder, steel slag byproduct, cement and / or clinker; and / or, The regulating agent includes sodium silicate, potassium silicate, sodium carbonate, sodium bicarbonate, potassium carbonate, aluminum hydroxide, polyacrylamide, triethanolamine, polyacrylic acid and / or polycarboxylate.

4. The method for preparing a concrete admixture according to claim 1, characterized in that: Placing the premix in a carbon-containing gas atmosphere and applying mechanical shear force to obtain an intermediate comprises: The premix is ​​placed in a preset container, a preset flow rate of carbon-containing gas is introduced, a mechanical shear force is applied, and the premix is ​​reacted under preset conditions to obtain an intermediate.

5. The method for preparing a concrete admixture according to claim 1, characterized in that: The mixing of the intermediate and the matured material according to a second preset component, wherein the solid phase component is the concrete admixture, comprises: mixing the intermediate with the cooked material according to a second preset composition to obtain a mixture; The mixture is subjected to a solid-liquid separation operation, and the obtained solid phase component is the concrete admixture.

6. The method for preparing a concrete admixture according to claim 1, characterized in that: The aging material includes a volcanic ash material and an activator in a second set ratio. Correspondingly, the intermediate is mixed with the aging material according to a second preset component to obtain a mixture, which includes: The intermediate, the pozzolanic material and the activator are mixed according to the second set ratio and the second preset composition to obtain a mixture.

7. The method for preparing a concrete admixture according to claim 6, characterized in that: The pozzolanic material comprises fly ash, blast furnace slag, silica fume, metakaolin and / or calcined clay; and / or, The activator includes dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, desulfurized gypsum, phosphogypsum, sodium sulfate, potassium sulfate and / or aluminum sulfate.

8. The method for preparing a concrete admixture according to claim 5, characterized in that: The solid-liquid separation operation is performed on the mixture to obtain the solid component as the concrete admixture, which includes: The mixture is placed in a solid-liquid separation device for dehydration treatment, and the obtained solid component is the concrete admixture.

9. A concrete admixture, characterized in that: The concrete admixture is prepared by the preparation method according to any one of claims 1 to 8.

10. A device for preparing concrete admixture, characterized in that: The concrete admixture preparation device comprises: A premixing unit, used for mixing carbonate-containing solid waste and cement-based composite material according to a first preset component to obtain a premix; A reaction unit, used for placing the premix in a carbon-containing gas atmosphere to apply mechanical shear force to obtain an intermediate; The processing unit is used to mix the intermediate with the matured material according to a second preset component, wherein the solid phase component is the concrete admixture.

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