Active exciting agent for ground fly ash as well as preparation method and application of active exciting agent

Abstract

The invention relates to the field of new materials, and particularly discloses an active activator for ground fly ash and a preparation method and application thereof.The active activator is prepared from, by weight, 3-7 parts of polycarboxylic acid additive, 2-4 parts of anhydrous sodium sulfate, 15-18 parts of alkylol amine and 2-6 parts of dextrose monohydrate; wherein the polycarboxylic acid additive is obtained by polymerizing diethylene glycol monovinyl ether and acrylic acid as monomers; the invention further discloses a preparation method of the active exciting agent. The preparation method comprises the following steps: uniformly mixing the raw materials according to the proportion to prepare the active exciting agent for the ground fly ash. The invention further discloses application of the active activator. The active activator and fly ash are mixed according to the mass ratio of 1: (900-1000) and then ground for application. The method has the characteristics of improving the activity of the fly ash and improving the mechanical property.

Description

Technical Field

[0001] The present application relates to the technical field of new materials, and more specifically, to an ultrafine fly ash activation and a preparation method and application thereof. Background Art

[0002] Among the many cementitious materials, the most commonly used one is silicate cement. However, the raw materials of this type of cement contain a large amount of calcium carbonate and silicon dioxide. These two substances will react and release a large amount of carbon dioxide during the calcination of cement raw materials, which is not good for the ecological environment. Therefore, a new type of gel material, fly ash, was later discovered. Its raw materials come from smoke emissions from power plants and other sources. Through equipment recovery and registration screening and processing, it forms a gelling material with certain activity. It is used in cement products to reduce the amount of cement used, thereby reducing carbon dioxide emissions, effectively improving the environment, and achieving sustainable development.

[0003] Fly ash is the powdery ash particles that are discharged from the flue and absorbed by the dust collector after the finely ground coal powder is burned in the boiler in a coal-fired power plant. The fly ash emissions generated by thermal power generation have become the largest single source of industrial solid waste pollution and the main component of industrial solid waste. Because it contains a large amount of volcanic ash active substances such as silicon dioxide, aluminum oxide, and calcium oxide, it is a potentially active volcanic ash powder that can be used as an admixture for building materials such as cement and concrete. The use of fly ash in the field of cementitious materials not only consumes a large amount of industrial waste slag, but also saves a large amount of artificial cementitious materials. Using fly ash as a blending material for silicate cement is an effective technical approach to treat and utilize fly ash.

[0004] The components of fly ash include active ingredients and glass with a smooth and hard surface. The presence of glass will hinder the hydration of active ingredients, resulting in low activity of fly ash in the early stage of use, affecting its content in cement and concrete. Although the current fly ash emissions are large, the utilization rate is low. By activating the activity of fly ash, its content in cementitious materials such as concrete and cement can be increased, thereby reducing dependence on natural resources and reducing production costs.

[0005] At present, the main physical and mechanical method is used to activate fly ash, that is, mechanical grinding is used to destroy the structure of the glass on the surface of fly ash, and at the same time, the specific surface area is further increased to stimulate the volcanic ash activity of silica and alumina in fly ash. As the fineness of fly ash increases, its activity does increase gradually, but its activity does not increase infinitely. When the fineness reaches a certain level, the activity no longer increases. In addition, if the fly ash continues to be ground, it will agglomerate, which will have an adverse effect on its activity. Moreover, the decrease in the fineness of fly ash is limited. At the same time, grinding fly ash requires crushing processing, which is costly, and a large amount of energy is consumed in the grinding production process, which is costly. It is necessary to provide a new fly ash activity stimulator to make the fly ash have better activity intensity. Summary of the invention

[0006] In order to improve the activity of fly ash and improve its mechanical properties, the present application provides an active activator for ground fly ash and a preparation method and application thereof.

[0007] In the first aspect, the present application provides an active activator for grinding fly ash, which adopts the following technical solution: An active activator for ground fly ash comprises the following raw materials in parts by weight: 3-7 parts of polycarboxylic acid additive, 2-4 parts of anhydrous sodium sulfate, 15-18 parts of alcoholamine, 2-6 parts of glucose monohydrate; The polycarboxylic acid additive is obtained by polymerizing diethylene glycol monovinyl ether and acrylic acid as monomers.

[0008] By adopting the above technical scheme, in the present application, anhydrous sodium sulfate and alcohol amine are used as active stimulants, and polycarboxylic acid is also added. Anhydrous sodium sulfate is used as an activator, and sulfate ions ionized in the aqueous solution can react with active components in fly ash, destroying the dense oxide shell layer on the surface of the spherical glass body of fly ash, exposing the internal aluminosilicate, thereby increasing the activity of fly ash, and sodium sulfate can also promote the reaction between fly ash and cement hydration products to generate more cementitious products such as hydrated calcium silicate and hydrated calcium aluminate, which helps to improve the strength and durability of fly ash concrete, and the addition of alcohol amine is alkaline in the aqueous solution, which can provide an alkaline environment that is conducive to the activation of fly ash activity, and helps the dissolution of active silica and alumina in fly ash and the hydration reaction.

[0009] In the present application, the polycarboxylic acid prepared by polymerization of diethylene glycol monovinyl ether and acrylic acid as monomers is in a chain-like comb-like form, which has a large steric hindrance effect and a high surface activity, so that the polycarboxylic acid body is easy to adsorb on the surface of the gel material fly ash. The polycarboxylic acid molecules adsorbed on the surface of the fly ash can prevent the agglomeration of the fly ash particles through their long chain structure and steric hindrance effect, thereby improving the dispersibility of the fly ash. This not only helps to expose more fly ash surfaces, but also facilitates the destruction of the oxide shell on the surface of the fly ash by mechanical action during the subsequent mechanical grinding of the fly ash, thereby exposing the active substances. Moreover, the carboxylic acid in the molecular structure of the polycarboxylic acid forms a chemical connection with the oxide on the surface of the fly ash, thereby reducing its surface energy and improving the reaction activity. Moreover, the carboxyl group can also complex with metal ions such as calcium in the fly ash, thereby destroying the oxide shell on the surface of the fly ash, exposing the active substances inside it and improving the activity. Furthermore, the hydrophilicity and permeability of the polycarboxylic acid molecules help to dissolve and peel off the oxide shell on the surface of the fly ash, thereby further exposing the active substances and playing an enhancing role.

[0010] In addition, the polycarboxylic acid prepared in the present application has good solubility with water and the above-mentioned alcohol amine, so that the polycarboxylic acid body can be effectively mixed with other components in the cement system, promoting the uniformity of the overall reaction, so that the active stimulant in the present application not only effectively improves the pozzolanic activity of the fly ash, but also can significantly improve the compressive strength and flexural strength of the fly ash product through the electrostatic repulsion dispersion effect, and can maintain sufficient strength and stability during long-term use, thereby improving durability.

[0011] In addition, the good compatibility of the polycarboxylic acid in the present application and the steric hindrance of the polycarboxylic acid adsorbed on the fly ash particles can prevent agglomeration, thereby maintaining good dispersibility and reducing water demand. The activation activator for ground fly ash in the present application can meet the requirement of significantly reducing water demand without changing the gel time of the ground fly ash, thereby improving the application effect of ground fly ash in cement products, and further improving the quality control requirements of cement products.

[0012] Optionally, the active activator for grinding fly ash comprises the following raw materials in parts by weight: 4 parts of polycarboxylic acid additive, 3 parts of anhydrous sodium sulfate, 4 parts of glucose monohydrate and 16 parts of alcoholamine.

[0013] By adopting the above-mentioned technical scheme, the addition of glucose monohydrate in the present application, on the one hand, utilizes its hygroscopic properties, so that when water seepage occurs in the fly ash-cement slurry, its hygroscopic effect can be exerted, thereby eliminating the water seepage phenomenon, and the hydroxyl and carboxyl active functional groups in glucose monohydrate are adsorbed on the surface of the fly ash through hydrogen bonds and the like, thereby reducing the water demand of the fly ash and ultimately reducing the water demand of the slurry.

[0014] Optionally, the alcohol amine includes one or more of triethanolamine, diethanol monoisopropanolamine, and triisopropanolamine.

[0015] Optionally, the alcohol amine comprises triethanolamine and diethanol monoisopropanolamine in a mass ratio of 1:(1.1-1.3).

[0016] By adopting the above technical scheme, the alcohol amine in this application selects triethanolamine enhanced alcohol amine and diethanol monoisopropanolamine production alcohol amine, both of which have good grinding aid effect, can refine fly ash particles, increase specific surface area, expose more active sites, and in addition, the alkaline environment of the two promotes the breaking of Si-O-Si, Si-O-Al and Al-O-Al bonds in the vitreous body, releases active silicon oxide and aluminum oxide, and then generates hydrated calcium silicate and hydrated calcium aluminate gel products with calcium hydroxide formed by cement hydration, significantly enhancing the activity of fly ash and playing a reinforcing role. When the two alcohol amines are selected in this application, the activation effect of grinding fly ash is better. If the amount of triethanolamine is too small, it fails to play a good emulsification and exfoliation effect and metal complexing effect, and affects the 28d compressive strength and 28d flexural strength of fly ash, and when the amount of diethanol monoisopropanolamine added is too small, the grinding efficiency is low, and good dispersibility cannot be brought, thereby reducing the water demand and failing to meet the process economy.

[0017] Optionally, the polycarboxylic acid additive is prepared by the following method: Diethylene glycol monovinyl ether is mixed with an initiator, preheated to 15-20°C, and acrylic acid is added dropwise under stirring within 40-60 minutes. After reacting for 30-60 minutes, the mixture is cooled and neutralized to obtain a polycarboxylic acid additive.

[0018] By adopting the above technical scheme, the polycarboxylic acid body prepared by the method provided in the present application is in a chain-like comb-like form, has high surface activity, good solubility with water and alcoholamine, and is easily adsorbed on fly ash and cementitious materials to produce steric hindrance. In addition, in the present application, acrylic acid is added dropwise at low temperature and polymerized under the action of an initiator to form a polycarboxylic acid additive, thereby reducing the occurrence of side reactions.

[0019] Optionally, during the preparation of the polycarboxylic acid additive, the molar ratio of diethylene glycol monovinyl ether to acrylic acid is (1-1.2):5, and the amount of initiator added is 1-3 wt % of the amount of diethylene glycol monovinyl ether added.

[0020] By adopting the above technical solution, the polycarboxylic acid additive prepared by using the above ratio has a better effect on stimulating the activity of fly ash.

[0021] Optionally, the activity stimulator also includes 2-5 parts by weight of polyethyleneimine. When the polycarboxylic acid additive is prepared, N,N'-methylenebisacrylamide and hydroxyethyl acrylate are added together with acrylic acid, and the amount of hydroxyethyl acrylate added is 20-30wt% of the amount of acrylic acid added, and the amount of N,N'-methylenebisacrylamide added is 5-10wt% of the amount of acrylic acid added.

[0022] By adopting the above technical scheme, polyethyleneimine is also added to the active activator in the present application, and N,N'-methylenebisacrylamide and hydroxyethyl acrylate are also added in the preparation process of polycarboxylic acid. N,N'-methylenebisacrylamide as a crosslinking agent can react with the copolymer of diethylene glycol monovinyl ether and acrylic acid to form a network structure with a greater steric hindrance effect, and the functional monomer of the hydroxyl functional group of hydroxyethyl acrylate introduces a hydroxyl group on the polycarboxylic acid molecular chain, thereby increasing the active sites for adsorption and reaction with fly ash, and further improving the activation effect of fly ash. Polyethyleneimine is an organic amine compound, and the amino group in its molecule reacts with fly ash. The surface functional groups such as silicon and oxygen react to form chemical bonds, which helps to destroy the dense structure of the fly ash surface, promote the dissolution of the internal active components, and improve the activity of the fly ash. In addition, it has a positive charge, which interacts with the negative charge on the fly ash surface to prevent particle agglomeration, and helps the uniform distribution and reaction of the active components. Polyethyleneimine cooperates with polycarboxylic acid bodies. The chemical modification and charge effect of polyethyleneimine synergize with the dispersion and chelation of polycarboxylic acid bodies. Polyethyleneimine destroys the surface structure of fly ash and releases active components, while polycarboxylic acid bodies promote the reaction between fly ash and activators through dispersion and chelation, and jointly promote the improvement of fly ash activity. In addition, polyethyleneimine added to the active activator is a highly branched polymer containing primary and secondary amines, and may also have a small amount of amino groups that form amide bonds with the carboxyl and hydroxyl groups in polycarboxylic acids, realizing the polymer connection between polyethyleneimine and polycarboxylic acids, thereby generating an activator with a greater steric hindrance effect, further improving the dispersion effect of fly ash, helping to expose more fly ash surfaces, and helping the subsequent fine grinding effect. At the same time, it also increases its contact area with the activator and improves the activation effect.

[0023] Optionally, the active stimulant further comprises 1-3 parts by weight of nano silicon powder-carboxymethyl cellulose composite microspheres, and the nano silicon powder-carboxymethyl cellulose composite microspheres are prepared by the following method: 1) dissolving carboxymethyl cellulose powder in a carboxymethyl cellulose solution having a mass concentration of 35-45 wt %; 2) Mix nano silicon powder and water in a mass ratio of 1:(4-6), and prepare nano silicon powder suspension by ultrasonic dispersion; 3) Add the carboxymethyl cellulose solution prepared in step 1) dropwise to the nano silicon powder suspension prepared in step 2), stir, heat to 45-55° C., then add calcium chloride solution dropwise, keep at 45-55° C. for 10-12 hours, filter and dry to obtain nano silicon powder-carboxymethyl cellulose composite microspheres; The added mass ratio of carboxymethyl cellulose powder to nano silicon powder is 1:(2-3), and the added amount of calcium chloride is 3-5wt% of the carboxymethyl cellulose powder.

[0024] By adopting the above technical solution, nano silicon powder is used as a reaction site to promote the dissolution and recrystallization of aluminosilicate minerals in fly ash. In this recrystallization process, more hydration products, such as hydrated calcium silicate, are generated. These products have a significant effect on the strength and durability of fly ash. The nano silicon powder has a very high specific surface area and surface activity due to its nano-scale particle size, so that the nano silicon powder can more effectively contact with the aluminosilicate minerals in fly ash, thereby accelerating the hydration reaction, making it easier to participate in the chemical reaction and reducing the activation energy of the reaction. Moreover, the silicon element in the nano silicon powder can react chemically with the aluminum element in the fly ash to generate new aluminosilicate minerals or hydration products, which have higher stability and strength and can further enhance the performance of fly ash. In addition, the nano silicon powder may also affect the distribution and migration of ions in the reaction system through adsorption and complexation, thereby indirectly promoting the hydration reaction. The addition of nano silicon powder has a certain positive effect on improving the activity of fly ash.

[0025] Carboxymethyl cellulose can react with metals such as calcium on the surface of fly ash to generate a hydrogel structure with a three-dimensional network structure. This structure helps to increase the active surface area of ​​fly ash and promote its reaction with cement hydration products. In the present application, nano silicon powder and carboxymethyl cellulose are compounded to prepare composite microspheres for addition. On the one hand, compared with the direct addition of nano silicon powder, it overcomes the disadvantage of easy agglomeration and poor dispersion. On the other hand, the silicate ions generated by the hydrolysis reaction of nano silicon powder in water in the composite microspheres can chemically react with the active components in the fly ash, promote the volcanic ash effect of the fly ash, generate new hydration products, and thus improve the activity of the fly ash. Moreover, the calcium ions introduced by the addition of calcium chloride in the preparation process of the composite microspheres react with the active components in the fly ash to generate more hydration products, further stimulating the activity of the fly ash.

[0026] In a second aspect, the present application provides a method for preparing an active activator for ground fly ash, using the following technical solution: A method for preparing an active activator for ground fly ash comprises the following steps: The raw materials are mixed evenly according to the proportion to obtain the active activator for ground fly ash.

[0027] By adopting the above technical solution, the preparation method provided by the present application is simple and convenient, the raw materials are easily available, and it is easy to realize industrialization.

[0028] In a third aspect, the present application provides an application of an active activator for grinding fly ash, using the following technical solution: The invention discloses an application of an active activator for grinding fly ash. The active activator is mixed with fly ash in a mass ratio of 1:(900-1000) and then ground and applied.

[0029] By adopting the above technical scheme, the prepared active activator is mixed with fly ash and then ground to work synergistically, thereby effectively improving the volcanic ash activity of the fly ash and improving the compressive strength and flexural strength of the fly ash product.

[0030] In summary, this application has the following beneficial effects: 1. In the present application, the polycarboxylic acid prepared by polymerization of diethylene glycol monovinyl ether and acrylic acid as monomers is in a chain-like comb-like form, which has a large steric hindrance effect and a high surface activity, so that the polycarboxylic acid body is easy to adsorb on the surface of the gel material fly ash. The polycarboxylic acid molecules adsorbed on the surface of the fly ash can prevent the agglomeration of the fly ash particles through their long chain structure and steric hindrance effect, thereby improving the dispersibility of the fly ash. This not only helps to expose more fly ash surfaces, but also helps to destroy the oxide shell on the surface of the fly ash by mechanical action during the subsequent mechanical grinding of the fly ash, thereby exposing active substances. In addition, the carboxylic acid in the molecular structure of the polycarboxylic acid forms a chemical connection with the oxide on the surface of the fly ash, thereby reducing its surface energy and improving the reaction activity. In addition, the carboxyl group can also complex with metal ions such as calcium in the fly ash, thereby destroying the oxide shell on the surface of the fly ash, exposing the active substances inside the fly ash, and improving the activity. In addition, the hydrophilicity and permeability of the polycarboxylic acid molecules help to dissolve and peel off the oxide shell on the surface of the fly ash, thereby further exposing the active substances and playing an enhancing role. 2. The polycarboxylic acid prepared in the present application has good compatibility with water and the above-mentioned alcohol amine, so that the polycarboxylic acid body can be effectively mixed with other components in the cement system, promoting the uniformity of the overall reaction, so that the active activator in the present application not only effectively improves the volcanic ash activity of the fly ash, but also can significantly improve the compressive strength and flexural strength of the fly ash product through the electrostatic repulsion dispersion effect, and can maintain sufficient strength and stability during long-term use, thereby improving durability; 3. The good compatibility of polycarboxylic acid in the present application and the steric hindrance of the polycarboxylic acid adsorbed on the fly ash particles can prevent agglomeration, thereby maintaining good dispersibility and reducing water demand. The activation activator for ground fly ash in the present application can meet the requirement of significantly reducing water demand without changing the gel time of ground fly ash, thereby improving the application effect of ground fly ash in cement products, and further improving the quality control requirements of cement products. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0032] Preparation Example 1 A method for preparing a polycarboxylic acid additive comprises the following steps: Diethylene glycol monovinyl ether and initiator ammonium persulfate were mixed, preheated to 18°C, acrylic acid was added dropwise under stirring, the addition was completed within 50 minutes, and then reacted for 40 minutes, cooled, neutralized, and a polycarboxylic acid additive was obtained.

[0033] The molar ratio of diethylene glycol monovinyl ether to acrylic acid is 1.1:5, and the added amount of the initiator is 2 wt % of the added amount of diethylene glycol monovinyl ether.

[0034] Preparation Example 2 A method for preparing a polycarboxylic acid additive comprises the following steps: Diethylene glycol monovinyl ether and initiator ammonium persulfate were mixed, preheated to 15°C, acrylic acid was added dropwise under stirring, the addition was completed within 40 minutes, and then reacted for 60 minutes, cooled, neutralized, and a polycarboxylic acid additive was obtained.

[0035] The molar ratio of diethylene glycol monovinyl ether to acrylic acid is 1:5, and the added amount of the initiator is 1 wt % of the added amount of diethylene glycol monovinyl ether.

[0036] Preparation Example 3 A method for preparing a polycarboxylic acid additive comprises the following steps: Diethylene glycol monovinyl ether and initiator ammonium persulfate were mixed, preheated to 20°C, acrylic acid was added dropwise under stirring, the addition was completed within 60 minutes, and then reacted for 30 minutes, cooled, neutralized, and a polycarboxylic acid additive was obtained.

[0037] The molar ratio of diethylene glycol monovinyl ether to acrylic acid is 1.2:5, and the added amount of the initiator is 3 wt % of the added amount of diethylene glycol monovinyl ether.

[0038] Preparation Example 4 A method for preparing a polycarboxylic acid additive is carried out according to the method in Preparation Example 1, except that N,N'-methylenebisacrylamide and hydroxyethyl acrylate are also added dropwise while acrylic acid is added dropwise, and the amount of hydroxyethyl acrylate added is 25wt% of the amount of acrylic acid added, and the amount of N,N'-methylenebisacrylamide added is 8wt% of the amount of acrylic acid added.

[0039] Preparation Example 5 A method for preparing a polycarboxylic acid additive is carried out according to the method in Preparation Example 1, except that N,N'-methylenebisacrylamide and hydroxyethyl acrylate are also added dropwise while acrylic acid is added dropwise, and the amount of hydroxyethyl acrylate added is 20wt% of the amount of acrylic acid added, and the amount of N,N'-methylenebisacrylamide added is 5wt% of the amount of acrylic acid added.

[0040] Preparation Example 6 A method for preparing a polycarboxylic acid additive is carried out according to the method in Preparation Example 1, except that N,N'-methylenebisacrylamide and hydroxyethyl acrylate are also added dropwise while acrylic acid is added dropwise, and the amount of hydroxyethyl acrylate added is 30wt% of the amount of acrylic acid added, and the amount of N,N'-methylenebisacrylamide added is 10wt% of the amount of acrylic acid added.

[0041] Example 1 A method for preparing an active activator for ground fly ash comprises the following steps: 4 kg of the polycarboxylic acid additive prepared in Preparation Example 1, 3 kg of anhydrous sodium sulfate and 16 kg of alcohol amine were uniformly mixed to prepare an active stimulant, wherein the alcohol amine was a mixture of triethanolamine and diethanol monoisopropanolamine in a mass ratio of 1:1.2.

[0042] Example 2 A method for preparing an active activator for ground fly ash comprises the following steps: 3 kg of the polycarboxylic acid additive prepared in Preparation Example 2, 2 kg of anhydrous sodium sulfate and 15 kg of alcohol amine were uniformly mixed to prepare an active stimulant, wherein the alcohol amine was a mixture of triethanolamine and diethanol monoisopropanolamine in a mass ratio of 1:1.1.

[0043] Example 3 A method for preparing an active activator for ground fly ash comprises the following steps: 7 kg of the polycarboxylic acid additive prepared in Preparation Example 3, 4 kg of anhydrous sodium sulfate and 18 kg of alcohol amine were uniformly mixed to prepare an active stimulator, wherein the alcohol amine was a mixture of triethanolamine and diethanol monoisopropanolamine in a mass ratio of 1:1.3.

[0044] Example 4 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that the polycarboxylic acid additive is the polycarboxylic acid additive prepared in Preparation Example 4.

[0045] Example 5 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that the polycarboxylic acid additive is the polycarboxylic acid additive prepared in Preparation Example 4, and 3 kg of polyethyleneimine is also added.

[0046] Example 6 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that the polycarboxylic acid additive is the polycarboxylic acid additive prepared in Preparation Example 5, and 2 kg of polyethyleneimine is also added.

[0047] Example 7 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that the polycarboxylic acid additive is the polycarboxylic acid additive prepared in Preparation Example 6, and 5 kg of polyethyleneimine is also added.

[0048] Example 8 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that 2 kg of nano silicon powder-carboxymethyl cellulose composite microspheres are added together with the polycarboxylic acid additive, wherein the nano silicon powder-carboxymethyl cellulose composite microspheres are prepared by the following method: 1) dissolving carboxymethyl cellulose powder in a carboxymethyl cellulose solution having a mass concentration of 40 wt%; 2) Mix nano silicon powder and water in a mass ratio of 1:5, and prepare nano silicon powder suspension by ultrasonic dispersion; 3) Add the carboxymethyl cellulose solution prepared in step 1) dropwise to the nano-silicon powder suspension prepared in step 2), stir, heat to 50° C., then add a 12 wt% calcium chloride solution dropwise, keep at 50° C. for 11 h, filter and dry to obtain nano-silicon powder-carboxymethyl cellulose composite microspheres; The added mass ratio of carboxymethyl cellulose powder to nano silicon powder is 1:2.5, and the added amount of calcium chloride is 3-5wt% of the carboxymethyl cellulose powder.

[0049] Example 9 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that 1 kg of nano silicon powder-carboxymethyl cellulose composite microspheres are added together with the polycarboxylic acid additive, wherein the nano silicon powder-carboxymethyl cellulose composite microspheres are prepared by the following method: 1) dissolving carboxymethyl cellulose powder in a carboxymethyl cellulose solution having a mass concentration of 35 wt %; 2) Mix nano silicon powder and water in a mass ratio of 1:4, and prepare nano silicon powder suspension by ultrasonic dispersion; 3) Add the carboxymethyl cellulose solution prepared in step 1) dropwise to the nano silicon powder suspension prepared in step 2), stir, heat to 45°C, then add a 10wt% calcium chloride solution dropwise, keep at 45°C for 12h, filter and dry to obtain nano silicon powder-carboxymethyl cellulose composite microspheres; The added mass ratio of carboxymethyl cellulose powder to nano silicon powder is 1:2, and the added amount of calcium chloride is 3wt% of the carboxymethyl cellulose powder.

[0050] Example 10 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that 3 kg of nano silicon powder-carboxymethyl cellulose composite microspheres are added together with the polycarboxylic acid additive, wherein the nano silicon powder-carboxymethyl cellulose composite microspheres are prepared by the following method: 1) dissolving carboxymethyl cellulose powder in a carboxymethyl cellulose solution having a mass concentration of 45 wt %; 2) Mix nano silicon powder and water in a mass ratio of 1:6, and prepare nano silicon powder suspension by ultrasonic dispersion; 3) Add the carboxymethyl cellulose solution prepared in step 1) dropwise to the nano silicon powder suspension prepared in step 2), stir, heat to 55° C., then add a 15 wt% calcium chloride solution dropwise, keep at 55° C. for 10 h, filter and dry to obtain nano silicon powder-carboxymethyl cellulose composite microspheres; The added mass ratio of carboxymethyl cellulose powder to nano silicon powder is 1:3, and the added amount of calcium chloride is 5wt% of the carboxymethyl cellulose powder.

[0051] Embodiment 11 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 8, except that an equal amount of nano-silicon powder-carboxymethyl cellulose composite microspheres is replaced by nano-silicon powder.

[0052] Example 12 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 8, except that an equal amount of nano-silicon powder-carboxymethyl cellulose composite microspheres is replaced by carboxymethyl cellulose.

[0053] Example 13 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 8, except that an equal amount of nano-silicon powder-carboxymethyl cellulose composite microspheres is replaced by a mixture of nano-silicon powder and carboxymethyl cellulose, and the nano-silicon powder and carboxymethyl cellulose are mixed in a mass ratio of 2.5:1 and then added.

[0054] Comparative Example 1 A method for preparing an active activator for ground fly ash is carried out according to the method in Example 1, except that no polycarboxylic acid additive is added to the raw material.

[0055] Comparative Example 2 A method for preparing an active stimulant for ground fly ash is carried out according to the method in Example 1, except that no glucose monohydrate is added to the raw material.

[0056] Application Example 1 An application of an active activator for grinding fly ash, the active activator prepared in Example 1 is mixed with fly ash in a mass ratio of 1:950 and then ground. The median particle size D50 of the ultrafine fly ash obtained after grinding is 25 μm, and the fly ash particle size range is 20-35 μm.

[0057] The fly ash is specifically composed of 25wt% red mud, 40wt% limestone, 25wt% clay, 6wt% aluminum ash and 4wt% copper sulfate.

[0058] Application Example 2 An application of an activating activator for grinding fly ash is carried out according to the method in Application Example 1, except that the activating activator prepared in Example 2 is mixed with fly ash in a mass ratio of 1:900 and then ground to obtain ultrafine fly ash.

[0059] Application Example 3 An application of an activating activator for grinding fly ash is carried out according to the method in Application Example 1, except that the activating activator prepared in Example 3 is mixed with fly ash in a mass ratio of 1:1000 and then ground to obtain ultrafine fly ash.

[0060] Application Example 4-13 The application of an activation activator for grinding fly ash is carried out according to the method in Application Example 1, except that the activation activators are the activation activators prepared in Examples 4-13 respectively.

[0061] Comparative application example 1 The application of an activation activator for grinding fly ash is carried out according to the method in Application Example 1, except that the activation activator is the activation activator prepared in Comparative Example 1.

[0062] Comparative Application Example 2 The application of an activation activator for grinding fly ash is carried out according to the method in Application Example 1, except that the activation activator is the activation activator prepared in Comparative Example 2.

[0063] Performance Testing The ultrafine fly ash, silicate cement clinker (PI 42.5) and gypsum prepared in the above application examples and comparative application examples were mixed in a mass ratio of 50:45:5, and then the cement mortar was molded according to GB / T17671-1999 "Test Method for Cement Mortar Strength (ISO Method)", and then cured, and the 3d compressive strength, flexural strength, and 28d compressive strength and flexural strength tests were performed. In addition, the ultrafine fly ash obtained by directly grinding the fly ash without adding an active activator was selected as the blank control group, and the above-mentioned compressive strength and flexural strength tests were also performed on the blank control group. The test results are shown in Table 1 below.

[0064] Table 1: Table 1 continued: Combined with the test results in Table 1 above, compared with the test results of the blank control group, in which fly ash and cement clinker were directly mixed and prepared without adding an activator, it can be seen that compared with the blank control group, the 3d strength and 28d strength of Example 1 were significantly increased. Referring to the test results of Example 1 and Example 4, it can be seen that when the polycarboxylic acid additive was prepared in Example 4, when N, N'-methylenebisacrylamide and hydroxyethyl acrylate were added together with the acrylic acid monomer, the 28d strength was enhanced, but the effect was small. Combined with the test results of Examples 5-7, when polyethyleneimine was added at the same time, the mechanical properties were significantly improved and the activity of the fly ash was significantly enhanced.

[0065] Referring to the test results of Example 1 and Examples 8-10, it can be seen that when nano-silicon powder-carboxymethyl cellulose composite microspheres are added to the active activator, the strength of the cement sizing agent is significantly improved. In combination with Example 11 and Example 12, when only nano-silicon powder is added, it can be seen that the strength may be reduced due to the easy agglomeration of nano-silicon powder, and the enhancement effect is limited when carboxymethyl cellulose is added. In Example 13, when nano-silicon powder and carboxymethyl cellulose are directly mixed and added, although it is enhanced, it is still limited compared to Example 8. When nano-silicon powder and carboxymethyl cellulose are compounded and added, the activation effect is better. Combined with the test results in Comparative Application Example 1, when no polycarboxylic acid additive is added to the active activator, its activation performance is significantly reduced.

[0066] In addition, according to GB / T1346-2011 "Test Method for Water Consumption, Setting Time and Stability of Cement Standard Consistency", the standard consistency water requirements in Example 1, the blank control group, Comparative Application Example 1 and Comparative Application Example 2 were tested, and it can be seen that when the initial setting time and the final setting time are kept to meet the requirements, the standard consistency water requirement in the blank control group is 25%, the water requirement in Example 1 is 24%, and when no polycarboxylic acid additive is added in Comparative Application Example 1, the water requirement is 30%. The present application provides an activation stimulant that greatly reduces the water requirement while maintaining the initial setting time and the final setting time requirements to meet the requirements. Referring to Comparative Application Example 2, it is found that the cement mortar prepared in Comparative Example 2 has water seepage, while the cement mortar prepared when monohydrated glucose is added to the application examples of the present application and Comparative Application Example 1 does not have water seepage.

[0067] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An active activator for ground fly ash, characterized in that: It includes the following raw materials in parts by weight: 3-7 parts of polycarboxylic acid additive, 2-4 parts of anhydrous sodium sulfate, 15-18 parts of alcoholamine, 2-6 parts of glucose monohydrate; The polycarboxylic acid additive is obtained by polymerizing diethylene glycol monovinyl ether and acrylic acid as monomers.

2. The activating agent for ground fly ash according to claim 1, characterized in that: The active activator for ground fly ash comprises the following raw materials in parts by weight: 4 parts of polycarboxylic acid additive, 3 parts of anhydrous sodium sulfate, 4 parts of glucose monohydrate and 16 parts of alcoholamine.

3. The activating agent for ground fly ash according to claim 1, characterized in that: The alcohol amine includes one or more of triethanolamine, diethanol monoisopropanolamine, and triisopropanolamine.

4. The activating agent for ground fly ash according to claim 1, characterized in that: The alcohol amine comprises triethanolamine and diethanol monoisopropanolamine in a mass ratio of 1:(1.1-1.3).

5. The activating agent for ground fly ash according to claim 1, characterized in that: The polycarboxylic acid additive is prepared by the following method: Diethylene glycol monovinyl ether is mixed with an initiator, preheated to 15-20°C, and acrylic acid is added dropwise under stirring within 40-60 minutes. After reacting for 30-60 minutes, the mixture is cooled and neutralized to obtain a polycarboxylic acid additive.

6. The activator for ground fly ash according to claim 5, characterized in that: During the preparation of the polycarboxylic acid additive, the molar ratio of diethylene glycol monovinyl ether to acrylic acid is (1-1.2):5, and the amount of initiator added is 1-3wt% of the amount of diethylene glycol monovinyl ether added.

7. The activator for ground fly ash according to claim 1, characterized in that: The activity stimulator also includes 2-5 parts by weight of polyethyleneimine. When the polycarboxylic acid additive is prepared, N,N'-methylenebisacrylamide and hydroxyethyl acrylate are added together with acrylic acid, and the amount of hydroxyethyl acrylate added is 20-30wt% of the amount of acrylic acid added, and the amount of N,N'-methylenebisacrylamide added is 5-10wt% of the amount of acrylic acid added.

8. The activating agent for ground fly ash according to claim 1, characterized in that: The active stimulant further comprises 1-3 parts by weight of nano silicon powder-carboxymethyl cellulose composite microspheres, and the nano silicon powder-carboxymethyl cellulose composite microspheres are prepared by the following method: 1) Dissolve carboxymethyl cellulose powder in a carboxymethyl cellulose solution having a mass concentration of 35-45 wt%; 2) Mix nano silicon powder and water in a mass ratio of 1: (4-6), and prepare nano silicon powder suspension by ultrasonic dispersion; 3) Add the carboxymethyl cellulose solution prepared in step 1) dropwise to the nano silicon powder suspension prepared in step 2), stir, heat to 45-55°C, then add calcium chloride solution dropwise, keep at 45-55°C for 10-12h, filter and dry to obtain nano silicon powder-carboxymethyl cellulose composite microspheres; The added mass ratio of carboxymethyl cellulose powder to nano silicon powder is 1:(2-3), and the added amount of calcium chloride is 3-5wt% of the carboxymethyl cellulose powder.

9. A method for preparing an activating activator for ground fly ash as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are mixed evenly according to the proportion to obtain the active activator for ground fly ash.

10. An application of the activator for ground fly ash as claimed in any one of claims 1 to 8, characterized in that: The active activator and fly ash are mixed in a mass ratio of 1: (900-1000) and then ground for application.

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