A cement strength stimulator and its preparation method and application

Abstract

The invention discloses a cement strength stimulator, a preparation method and application thereof. The components are as follows by mass: 12 to 25 parts of a seed accelerator, 3 to 6 parts of a polyolamine compound A, 36 to 52 parts of cement kiln bypass vent dust, and 45 to 70 parts of modified lithium slag. The preparation method of the modified lithium slag comprises the following steps: drying the lithium slag at 100 to 110° C., fully mixing the dried lithium slag with a 20 to 30 wt% polyolamine aqueous solution and aging for 1 to 2 hours, and finally drying and dehydrating at 45 to 60° C. to obtain the modified lithium slag. Based on the characteristics of cement hydration, the invention significantly promotes the dissolution of ions in the early hydration process of cement, reduces the nucleation barrier of hydration products and promotes nucleation, continuously releases substances that promote cement hydration, improves the density of cement hydration products, thereby improving the cement hydration rate and degree, has a significant stimulating effect on the strength of cement at various ages, effectively utilizes industrial waste slag, and has a simple preparation method.

Description

Technical Field

[0001] The invention belongs to the technical field of materials, and in particular relates to a cement strength stimulator and a preparation method and application thereof. Background Art

[0002] Cement clinker has the highest carbon emission among cement raw materials, but it is also the main source of cement strength. Therefore, effectively stimulating cement strength can reduce the amount of clinker while ensuring the same cement strength, thereby reducing cement carbon emissions. Cement admixtures have been widely used as materials that can improve cement performance, and cement enhancers, as one of them, can effectively stimulate cement strength. From the perspective of existing technology, the main component of cement enhancement is alcoholamine substances, which accelerate the dissolution of various ions produced by cement hydration through complexation, thereby promoting cement hydration and increasing strength. However, the effect of a single complexation on cement strength stimulation is limited, and it is difficult to stably obtain good results due to changes in the chemical composition of cement. How to combine the characteristics of cement hydration to further stimulate cement strength is very necessary to make up for the shortcomings of existing technologies and reduce carbon emissions in the cement production process. In this process, if industrial solid waste can be effectively utilized in combination with its characteristics, its significance will be even greater.

[0003] CN1241545A discloses a cement strength stimulator comprising a composite surfactant and cement paste embryos, wherein the composite surfactant is composed of triethanolamine and triisopropanolamine. The composite surfactant and cement paste embryos are pulverized, stirred, and then packaged into finished products. However, cement paste embryos are the product of cement hydration, obtained by adding water to cement. They have a complete hydration product structure and crystal form, and after pulverization, their size is at least micrometer-sized, resulting in limited cement strengthening effects. Summary of the Invention

[0004] The purpose of the present invention is to provide a cement strength stimulator and its preparation method and application. Starting from the characteristics of cement hydration, the present invention greatly promotes the dissolution of ions in the early hydration process of cement, reduces the nucleation barrier of hydration products to promote nucleation, continuously releases substances that promote cement hydration, and improves the density of cement hydration products, thereby improving the cement hydration rate and degree. It has a significant stimulating effect on the strength of cement at all ages, while effectively utilizing industrial waste residues and having a simple preparation method.

[0005] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0006] A cement strength stimulator, the components of which are calculated by mass as follows:

[0007]

[0008] According to the above scheme, the seed crystal accelerator is obtained by mixing silicate cement with a zwitterionic polymer aqueous solution and then drying it, and the particle size range is 5 to 200 nm.

[0009] According to the above scheme, the polyol amine compound A is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, tetrahydroxyethyl ethylenediamine or any mixture thereof.

[0010] According to the above scheme, the chemical composition of the cement kiln bypass ash is CaO ≥ 35%, K2O ≥ 15%, Na2O ≥ 1%, 10% ≤ Cl - ≤20%.

[0011] According to the above scheme, the modified lithium slag is lithium slag that is saturated with the polyol amine compound B; the lithium slag is waste slag generated during lithium ore processing and has a particle size range of 10 to 200 μm.

[0012] According to the above scheme, the preparation method of the seed crystal promoter includes the following steps:

[0013] The zwitterionic polymer is added to water to prepare a 1-3 wt% solution, and silicate cement is added under stirring for 2-4 hours. The reaction is continued for 2-3 hours, and the product is dried at 45-60°C to obtain a seed crystal accelerator.

[0014] The silicate cement is P·I type silicate cement; the zwitterionic polymer is a copolymer of carboxylic acid and carboxylic acid betaine, and its weight average molecular weight is 20000-40000 g / mol; the mass ratio of the zwitterionic polymer to the silicate cement is 1:(6-10).

[0015] According to the above scheme, the preparation method of the modified lithium slag comprises the following steps:

[0016] The lithium slag is dried at 100-110° C., the dried lithium slag is fully mixed with a 20-30 wt % aqueous solution of polyol amine and aged for 1-2 hours, and finally dried and dehydrated at 45-60° C. to obtain modified lithium slag;

[0017] The polyol amine compound B is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, and tetrahydroxyethyl ethylenediamine, or any mixture thereof; the mass ratio of the lithium slag to the polyol amine compound is (4-9):1.

[0018] The preparation method of the cement strength stimulator comprises the following steps:

[0019] The seed crystal accelerator, the polyol amine compound A, the cement kiln bypass vent ash and the modified lithium slag are mixed and stirred uniformly to obtain a cement strength activator.

[0020] The application of the above-mentioned cement strength stimulator in the process of preparing cement includes grinding it together with the raw materials during the cement grinding process.

[0021] According to the above solution, the dosage of the cement strength stimulator is 0.3-0.5 wt% of the total mass of the raw materials in the cement grinding process.

[0022] The seed crystal accelerator in the present invention is obtained by reacting P·I type Portland cement with an aqueous solution of a carboxylic acid and carboxylic acid betaine copolymer and then drying it. When P·I type Portland cement comes into contact with water, ions in C3S, C3A, and gypsum minerals rapidly dissolve and react to form calcium silicate hydrate and ettringite hydration products. The formation rate of these hydration products can be controlled by slowly adding the P·I type Portland cement. The carboxylic acid and carboxylic acid betaine copolymer has a unique molecular structure and physicochemical properties, resulting in extremely strong hydration ability. The negatively charged carboxyl groups in the structure effectively adsorb on the surface of the positively charged C3A hydration product, ettringite, while the positively charged betaine groups in the structure effectively adsorb on the surface of the positively charged C3S hydration product, calcium silicate hydrate. This forms a dense polymer hydration layer, preventing the large-scale aggregation of ions in C3S, C3A, and gypsum minerals when the P·I type Portland cement comes into contact with water, thereby dispersing the ions and forming nanoscale calcium silicate hydrate and ettringite. In addition, the copolymer of carboxylic acid and carboxylic acid betaine also has a unique "anti-polyelectrolyte effect". When it encounters inorganic salt ions formed by cement hydration products, its viscosity will increase, which can effectively prevent the precipitation and aggregation of cement hydration products, further ensuring the formation of nano-scale hydrated calcium silicate and calcium aluminite. Compared with the common single nano-hydrated calcium silicate gel cement early strength agent, the seed crystal accelerator prepared by the present invention has various crystal nuclei of cement hydration products, which can greatly reduce the nucleation barrier formed by various hydration products during cement hydration. At the same time, the higher surface free energy gives the seed crystal the ability to adsorb ions and molecules. The dual effects of adsorption and nucleation can change the hydration process of cement, alleviate the high-concentration shielding effect of the original mineral interface, the crystallization pressure caused by short-range crystallization and crystallization, thereby effectively promoting cement hydration and stimulating cement strength.

[0023] The hydroxyl and amino groups in the compound structure of polyol amine can effectively complex the Ca generated during cement hydration. 2+ 、Al 3+ 、Fe 3+ ions, increase their dissolution rate, promote cement hydration, and improve the strength of cement paste.

[0024] Cement kiln bypass ash is a waste generated during the cement clinker production process, which contains a large amount of Ca 2+ , K + 、Na + 、Cl -Compared with Ca in cement minerals, calcium in cement kiln bypass ash dissolves faster and has higher activity when it comes into contact with water, which can provide Ca for the early stage of cement hydration. 2+ , thereby promoting the formation of cement hydration products; K + 、Na + After cement is mixed with water, it quickly dissolves in the liquid phase, changes the liquid phase environment, and thus increases the saturation of CSH, makes its nucleation faster, shortens the induction period and accelerates hydration; Cl - It can form insoluble matter with CSH, thereby accelerating the formation of CSH precipitation, which is beneficial to the cement hydration reaction in the positive direction and accelerates cement hydration.

[0025] Lithium slag is the solid waste residue produced during the lithium extraction process from lithium ore. It has a porous structure and a large internal specific surface area. After drying, the lithium slag is thoroughly mixed with an aqueous solution of a polyolamine compound and then aged. The polyolamine compound can be adsorbed and filled into the porous structure of the lithium slag. Due to the "cavity effect" and "surface effect," this adsorption is very stable, effectively preventing the polyolamine compound from being absorbed onto the surface of hydration products during the early hydration of cement and being "buried" and consumed by further hydration products. As the cement hydration reaction continues, the pH value of the system continues to increase. The hydration product, Ca(OH)2, causes the lithium slag to dissociate, releasing the polyolamine compound, which promotes the later hydration of the cement and stimulates its later strength. Simultaneously, the lithium slag can undergo a secondary hydration reaction, with the hydration products filling the voids in the late hydration phase of the cement, making the cement stone structure more compact and improving its later strength.

[0026] The components of the present invention can work synergistically with each other to achieve a better reinforcement effect. Cement hydration is the process in which cement minerals are dissolved and reacted to form precipitation after adding water. The hydroxyl and amino groups in the compound structure of polyol amine can effectively complex the Ca generated during cement hydration. 2+ 、Al 3+ 、Fe 3+ ions, forming complexes with lower solubility. Ca in cement kiln bypass ash 2+ 、Cl - It can be adsorbed on the surface of calcium silicate hydrate to form composite hydrated silicate; at the same time, it can react with cement in the presence of gypsum to form hydrated chloroaluminate. 2+Under the combined action of chlorinated amines and Cl-, cement hydration generates the even less soluble "alkanolamine-Cl-CSH" and "alkanolamine-Cl-AFt" products. These products rapidly grow on the CSH and AFt nuclei provided by the seed accelerator, significantly accelerating the early hydration rate of the cement. Furthermore, the polyolamine compounds released from the modified lithium slag ensure the sustainability of this effect, thereby promoting the later hydration of the cement. This significant improvement in early strength and its sustained improvement over time is unattainable by any single component.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The raw materials of the cement strength stimulator provided by the present invention are easily available and effectively utilize solid waste. The preparation method is simple, and industrialization can be realized, which supports the concept of green development of composite building materials.

[0029] 2. The cement strength activator provided by the present invention has a seed accelerator containing various crystal nuclei of cement hydration products, and the seed accelerator is a stable nanoscale crystal nucleus that can significantly promote the formation of various hydration products.

[0030] 3. The cement strength activator provided by the present invention fully utilizes the component characteristics of cement kiln bypass ash and significantly accelerates cement hydration;

[0031] 4. The cement strength stimulator provided by the present invention utilizes the inherent characteristics and porous structure of lithium slag combined with the strengthening effect of polyol amines to promote the late hydration of cement while making the cement stone structure more dense, effectively stimulating the late strength of cement;

[0032] 5. The different components in the present invention work synergistically to promote cement hydration and stimulate early strength of cement from multiple aspects, such as providing ions required for hydration, promoting the dissolution of cement ions, generating hydration products with lower solubility, accelerating nucleation, and promoting the formation of hydration products; continuously releasing substances that promote cement hydration, filling the voids in cement stone, and thus improving the later strength of cement, thereby achieving the stimulation of cement strength and significantly improving the strength of cement at all ages. DETAILED DESCRIPTION

[0033] The following examples further illustrate the technical solutions of the present invention, but are not intended to limit the scope of protection of the present invention. The following specific examples are only some preferred embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, modifications, substitutions, and improvements made by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0034] The specific embodiment provides a cement strength stimulator, the components of which are as follows by mass:

[0035] 12 to 25 parts of seed crystal accelerator; 3 to 6 parts of polyol amine compound A; 36 to 52 parts of cement kiln bypass vent dust; and 45 to 70 parts of modified lithium slag.

[0036] Specifically, the seed crystal accelerator is obtained by mixing silicate cement with a zwitterionic polymer aqueous solution and then drying the mixture, and has a particle size range of 5 to 200 nm.

[0037] Specifically, the polyol amine compound A is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, and tetrahydroxyethyl ethylenediamine, or any mixture thereof.

[0038] Specifically, the chemical composition of the cement kiln bypass ash is CaO ≥ 35%, K2O ≥ 15%, Na2O ≥ 1%, 10% ≤ Cl - ≤20%.

[0039] Specifically, the modified lithium slag is lithium slag that is saturated with the polyol amine compound B; the lithium slag is waste slag generated during lithium ore processing and has a particle size range of 10 to 200 μm.

[0040] A specific embodiment provides a method for preparing the seed crystal promoter, comprising the following steps:

[0041] A zwitterionic polymer is added to water to prepare a 1-3 wt% solution, and silicate cement is added under stirring for 2-4 hours, followed by further reaction for 2-3 hours. The product is dried at 45-60° C. to obtain a seed crystal accelerator. The silicate cement is P·I type silicate cement. The zwitterionic polymer is a copolymer of carboxylic acid and carboxylic acid betaine, and its weight-average molecular weight is 20,000-40,000 g / mol. The mass ratio of the zwitterionic polymer to the silicate cement is 1:(6-10).

[0042] A specific embodiment provides a method for preparing the modified lithium slag, comprising the following steps:

[0043] The lithium slag is dried at 100-110° C., the dried lithium slag is fully mixed with a 20-30 wt% aqueous solution of a polyol amine and aged for 1-2 hours, and finally dried and dehydrated at 45-60° C. to obtain a modified lithium slag; the polyol amine compound B is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, and tetrahydroxyethyl ethylenediamine, or any mixture thereof; and the mass ratio of the lithium slag to the polyol amine compound is (4-9):1.

[0044] The specific embodiment also provides a preparation method of the cement strength stimulator as follows:

[0045] The seed crystal accelerator prepared in the step, the polyol amine compound, the cement kiln bypass vent ash and the prepared modified lithium slag are mixed and stirred evenly to obtain a cement strength activator.

[0046] Specifically, the carboxylic acid and carboxylic acid betaine copolymer is commercially available from Xiamen Sinobond Biotechnology Co., Ltd. The product is referred to as PCBTh-co-ThAA, has a weight-average molecular weight of 20,000 to 40,000 g / mol, and has the following structural formula:

[0047]

[0048] The following examples use a preferred copolymer of carboxylic acid and carboxylic acid betaine having a weight average molecular weight of 30,000 g / mol.

[0049] The remaining raw materials can be obtained from the market unless otherwise specified.

[0050] The specific embodiment also provides the use of the cement strength stimulant in the cement preparation process, including grinding the cement together with the raw materials during the cement grinding process. The amount of the cement strength stimulant is 0.3-0.5wt% of the total weight of the raw materials during the cement grinding process.

[0051] Example 1

[0052] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 990.00 g of water to prepare a 1.0% solution. 60 g of P·I type Portland cement was slowly added at 400 r / min while stirring. The addition was completed over 2 h. The reaction was continued for 2 h. After the reaction was completed, the product was dried at 45° C. to obtain a seed accelerator.

[0053] (2) Preparation of modified lithium slag: The lithium slag was dried at 100° C., 80 g of the dried lithium slag was thoroughly mixed with 100 g of a 20 wt % triethanolamine aqueous solution, and then aged for 1 h. Finally, the mixture was dried and dehydrated at 45° C. to obtain the modified lithium slag.

[0054] (3) Preparation of cement strength activator: 12 parts of seed crystal accelerator prepared in step (1), 3 parts of tetrahydroxyethylethylenediamine, 36 parts of cement kiln bypass vent ash, and 45 parts of modified lithium slag prepared in step (2) are mixed and stirred uniformly to obtain a cement strength activator.

[0055] Example 2

[0056] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 323.33 g of water to prepare a 1.5% solution. 65 g of P·I type Portland cement was slowly added at 523 r / min while stirring. The addition was completed over 2.5 h. The reaction was continued for 2.2 h. After the reaction was completed, the product was dried at 47° C. to obtain a seed accelerator.

[0057] (2) Preparation of modified lithium slag: The lithium slag was dried at 105° C., 261 g of the dried lithium slag was thoroughly mixed with 100 g of a 29 wt % aqueous solution of hydroxyethyldiisopropanolamine, and then aged for 1.5 h. Finally, the mixture was dried and dehydrated at 49° C. to obtain the modified lithium slag;

[0058] (3) Preparation of cement strength activator: 25 parts of seed crystal accelerator prepared in step (1), 6 parts of diethanol monoisopropanolamine, 52 parts of cement kiln bypass vent ash, and 70 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain a cement strength activator.

[0059] Example 3

[0060] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 656.67 g of water to prepare a 3.0% solution. 100 g of P·I type Portland cement was slowly added at 600 r / min while stirring. The addition was completed over 4 h. The reaction was continued for 3 h. After the reaction was completed, the product was dried at 60° C. to obtain a seed accelerator.

[0061] (2) Preparation of modified lithium slag: The lithium slag was dried at 110° C., 270 g of the dried lithium slag was thoroughly mixed with 100 g of a 30 wt % diethanol monoisopropanolamine aqueous solution, and then aged for 2 h. Finally, the mixture was dried and dehydrated at 60° C. to obtain the modified lithium slag.

[0062] (3) Preparation of cement strength activator: 18 parts of seed crystal accelerator prepared in step (1), 5 parts of triethanolamine, 44 parts of cement kiln bypass vent ash, and 58 parts of modified lithium slag prepared in step (2) are mixed and stirred uniformly to obtain a cement strength activator.

[0063] Example 4

[0064] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 390.00 g of water to prepare a 2.5% solution. 76 g of P·I type Portland cement was slowly added at 452 rpm while stirring. The addition was completed over 3 h. The reaction was continued for 2.5 h. After the reaction was completed, the product was dried at 53° C. to obtain a seed accelerator.

[0065] (2) Preparation of modified lithium slag: The lithium slag was dried at 103° C., 84 g of the dried lithium slag was thoroughly mixed with 100 g of a 21 wt % triisopropanolamine aqueous solution, and then aged for 1.3 h. Finally, the mixture was dried and dehydrated at 46° C. to obtain the modified lithium slag;

[0066] (3) Preparation of cement strength activator: 12 parts of seed crystal accelerator prepared in step (1), 6 parts of triisopropanolamine, 36 parts of cement kiln bypass vent ash, and 70 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain cement strength activator.

[0067] Example 5

[0068] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 347.14 g of water to prepare a 2.8% solution. 99 g of P·I type Portland cement was slowly added at 598 rpm while stirring. The addition was completed over 3.8 h. The reaction was continued for 2.7 h. After the reaction was completed, the product was dried at 58° C. to obtain a seed accelerator.

[0069] (2) Preparation of modified lithium slag: The lithium slag was dried at 106° C., 125 g of the dried lithium slag was thoroughly mixed with 100 g of a 25 wt % aqueous solution of tetrahydroxyethylethylenediamine, and then aged for 1.8 h. Finally, the mixture was dried and dehydrated at 59° C. to obtain the modified lithium slag.

[0070] (3) Preparation of cement strength activator: 25 parts of seed accelerator prepared in step (1), 3 parts of hydroxyethyl diisopropanolamine, 52 parts of cement kiln bypass vent ash, and 45 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain a cement strength activator.

[0071] Example 6

[0072] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 578.24 g of water to prepare a 1.7% solution. 85 g of P·I type Portland cement was slowly added at 403 rpm while stirring. The addition was completed over 2.1 h. The reaction was continued for 2.9 h. After the reaction was completed, the product was dried at 42° C. to obtain a seed accelerator.

[0073] (2) Preparation of modified lithium slag: The lithium slag was dried at 104° C., 150 g of the dried lithium slag was thoroughly mixed with 100 g of a 25 wt % triisopropanolamine aqueous solution, and then aged for 1.1 h. Finally, the mixture was dried and dehydrated at 52° C. to obtain the modified lithium slag.

[0074] (3) Preparation of cement strength activator: 14 parts of seed crystal accelerator prepared in step (1), 5 parts of triethanolamine, 38 parts of cement kiln bypass vent ash, and 69 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain cement strength activator.

[0075] Example 7

[0076] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 899.09 g of water to prepare a 1.1% solution. 80 g of P·I type Portland cement was slowly added at 422 r / min while stirring. The addition was completed over 3.6 h. The reaction was continued for 2.1 h. After the reaction was completed, the product was dried at 44° C. to obtain a seed accelerator.

[0077] (2) Preparation of modified lithium slag: The lithium slag was dried at 101° C., 168 g of the dried lithium slag was thoroughly mixed with 100 g of a 24 wt % diethanol monoisopropanolamine aqueous solution, and then aged for 1.6 h. Finally, the mixture was dried and dehydrated at 51° C. to obtain the modified lithium slag;

[0078] (3) Preparation of cement strength activator: 21 parts of seed accelerator prepared in step (1), 4 parts of diethanol monoisopropanolamine, 50 parts of cement kiln bypass vent ash, and 49 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain a cement strength activator.

[0079] Example 8

[0080] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 490.00 g of water to prepare a 2.0% solution. 92 g of P·I type Portland cement was slowly added at 579 rpm while stirring. The addition was completed over 2.9 h. The reaction was continued for 2.4 h. After the reaction was completed, the product was dried at 48° C. to obtain a seed accelerator.

[0081] (2) Preparation of modified lithium slag: The lithium slag was dried at 109° C., 216 g of the dried lithium slag was thoroughly mixed with 100 g of a 27 wt % triethanolamine aqueous solution, and then aged for 1.7 h. Finally, the mixture was dried and dehydrated at 58° C. to obtain the modified lithium slag.

[0082] (3) Preparation of cement strength activator: 22 parts of seed accelerator prepared in step (1), 5 parts of triisopropanolamine, 37 parts of cement kiln bypass vent ash, and 48 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain a cement strength activator.

[0083] Example 9

[0084] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 516.32 g of water to prepare a 1.9% solution. 75 g of P·I type Portland cement was slowly added at 542 rpm while stirring. The addition was completed over 2.3 h. The reaction was continued for 2.3 h. After the reaction was completed, the product was dried at 59° C. to obtain a seed accelerator.

[0085] (2) Preparation of modified lithium slag: The lithium slag was dried at 104° C., 130 g of the dried lithium slag was thoroughly mixed with 100 g of a 26 wt % aqueous solution of tetrahydroxyethylethylenediamine, and then aged for 2 h. Finally, the mixture was dried and dehydrated at 47° C. to obtain the modified lithium slag.

[0086] (3) Preparation of cement strength activator: 15 parts of seed accelerator prepared in step (1), 4 parts of tetrahydroxyethylethylenediamine, 47 parts of cement kiln bypass vent ash, and 58 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain cement strength activator.

[0087] Example 9

[0088] (1) Preparation of seed accelerator: 10 g of carboxylic acid and carboxylic acid betaine copolymer was added to 424.78 g of water to prepare a 2.3% solution. 78 g of P·I type Portland cement was slowly added at 500 r / min while stirring. The addition was completed over 3.4 hours. The reaction was continued for 3 hours. After the reaction was completed, the product was dried at 55° C. to obtain a seed accelerator.

[0089] (2) Preparation of modified lithium slag: The lithium slag was dried at 108°C, 168 g of the dried lithium slag was thoroughly mixed with 100 g of a 28 wt% aqueous solution of hydroxyethyldiisopropanolamine, and then aged for 1 h. Finally, the mixture was dried and dehydrated at 43°C to obtain the modified lithium slag.

[0090] (3) Preparation of cement strength activator: 19 parts of seed accelerator prepared in step (1), 5 parts of hydroxyethyl diisopropanolamine, 39 parts of cement kiln bypass vent ash, and 63 parts of modified lithium slag prepared in step (2) were mixed and stirred uniformly to obtain a cement strength activator.

[0091] Comparative Example 1

[0092] Example 1 was repeated, but no seed accelerator was added during the preparation of the cement strength activator.

[0093] Comparative Example 2

[0094] Example 2 was repeated, but cement kiln bypass vent ash was not added during the preparation of the cement strength activator.

[0095] Comparative Example 3

[0096] Example 3 was repeated, and the modified lithium slag was replaced with an equal amount of dried lithium slag during the preparation of the cement strength activator.

[0097] Comparative Example 4

[0098] Example 4 was repeated, except that the modified lithium slag was replaced by triisopropanolamine having the same mass as that in the modified lithium slag during the preparation of the cement strength activator.

[0099] Comparative Example 5

[0100] Repeat Example 4, and replace the seed accelerator with a commercially available CSH gel early strength agent (manufacturer: Shanghai Sanrui Polymer Materials Co., Ltd., product name: TDSCN VIVID-300CCN Concrete Strong Crystal Core) of equal quality during the preparation of the cement strength activator.

[0101] The samples prepared in Examples 1 to 10 and Comparative Examples 1 to 5 above and a commercially available cement liquid enhancer (mainly composed of diethanol monoisopropanolamine and sodium chloride) were tested and evaluated.

[0102] 1. Crystallization accelerator particle size test

[0103] The particle size of the samples prepared in Examples 1 to 10 was measured using STEM, and the results are as follows:

[0104] Table 1 Particle size of crystal nucleation accelerator

[0105] Sample number Particle size range / nm Example 1 6～150 Example 2 50～183 Example 3 15～115 Example 4 101～196 Example 5 87～169 Example 6 32～167 Example 7 41～153 Example 8 23～142 Example 9 9～123 Example 10 63～175

[0106] It can be seen from Table 1 that the particle size of the prepared crystal nucleation promoter ranges from 5 to 200 nm.

[0107] 2. Performance Evaluation

[0108] Referring to the test method in GB / T 26748-2011 "Cement Grinding Aids," 5 kg of various cement raw materials were added to a test mill at a P.O. 4 to 2.5 cement ratio (80% clinker, 5% slag, 5% fly ash, 5% limestone, and 5% gypsum). The samples were added to the cement raw materials before grinding, and the grinding time was fixed at 23 minutes. Cement performance was evaluated. The blank sample dosage was 0%, the samples prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were added at a dosage of 0.4%, and the commercially available liquid cement enhancer was added at a dosage of 0.05%.

[0109] The prepared cement was added with water to form a slurry. The hydration degree of the cement slurry after curing at different ages was measured using the non-evaporative water method. The results are shown in the following table:

[0110] Table 2 Cement hydration degree

[0111]

[0112]

[0113] As can be seen from Table 2, compared with the blank, after adding the cement strength stimulators prepared in Examples 1 to 10, the hydration degree of cement at each age was significantly improved, indicating that the cement strength stimulator effectively promoted the hydration of cement and improved the hydration degree of cement. Compared with commercially available enhancers, the hydration degree of cement at each age was higher, indicating that the cement strength stimulators prepared in Examples 1 to 10 were more effective in improving the hydration degree of cement than commercially available enhancers. Compared with Comparative Examples 1 to 5, the hydration degree of cement at each age was higher, indicating that the cement strength stimulators prepared in Examples 1 to 10 were more effective in improving the hydration degree of cement, and that the lack or replacement of any of the materials could not achieve a better effect.

[0114] The mortar strength was measured with reference to GB / T 17671-1999 "Test method for cement mortar strength (ISO method)". The results are shown in the following table:

[0115] Table 3 Cement mortar strength

[0116]

[0117] As can be seen from Table 3, compared to the blank, the addition of the cement strength stimulators prepared in Examples 1 to 10 significantly improved the strength of the cement at each age, indicating that the cement strength stimulators effectively promoted hydration and stimulated cement strength. Compared to commercially available strengthening agents, the strength of the cement at each age was higher, indicating that the cement strength stimulators prepared in Examples 1 to 10 were more effective in stimulating cement strength than commercially available strengthening agents. Compared to Comparative Examples 1 to 5, the strength of the cement at each age was higher, indicating that the cement strength stimulators prepared in Examples 1 to 10 were more effective in stimulating cement strength, and that the superior effect could not be achieved without or in place of any of the above materials.

Claims

1. A cement strength stimulator, characterized in that The components are calculated in parts by mass as follows: 12 to 25 parts of seed crystal promoter, 3 to 6 parts of polyol amine compound A, Cement kiln bypass ash 36 to 52 parts, 45 to 70 parts of modified lithium slag; The preparation method of the seed crystal promoter comprises the following steps: The zwitterionic polymer is added to water to prepare a 1-3 wt% solution, and silicate cement is added under stirring for 2-4 hours. The reaction is continued for 2-3 hours, and the product is dried at 45-60°C to obtain a seed crystal accelerator. The silicate cement is P·I type silicate cement; the zwitterionic polymer is a copolymer of carboxylic acid and carboxylic acid betaine, and its weight average molecular weight is 20000~40000g / mol; the mass ratio of the zwitterionic polymer to the silicate cement is 1:(6~10); The preparation method of the modified lithium slag comprises the following steps: The lithium slag is dried at 100-110° C., the dried lithium slag is fully mixed with a 20-30 wt % aqueous solution of a polyol amine compound B and aged for 1-2 hours, and finally dried and dehydrated at 45-60° C. to obtain a modified lithium slag; The polyolamine compound B is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, and tetrahydroxyethyl ethylenediamine, or any mixture thereof; the mass ratio of the lithium slag to the polyolamine compound is (4-9):

1.

2. The cement strength stimulator according to claim 1, characterized in that The seed crystal accelerator is obtained by mixing silicate cement with a zwitterionic polymer aqueous solution and then drying the mixture, and has a particle size range of 5 to 200 nm.

3. The cement strength stimulator according to claim 1, characterized in that The polyol amine compound A is one of triethanolamine, diethanol monoisopropanolamine, hydroxyethyl diisopropanolamine, triisopropanolamine, tetrahydroxyethyl ethylenediamine, or any mixture thereof.

4. The cement strength stimulator according to claim 1, characterized in that The chemical composition of the cement kiln bypass ash is CaO ≥ 35%, K2O ≥ 15%, Na2O ≥ 1%, 10% ≤ Cl - ≤20%.

5. The cement strength stimulator according to claim 1, characterized in that The modified lithium slag is lithium slag that is saturated with the polyol amine compound B; the lithium slag is waste slag generated during lithium extraction from lithium ore processing, and has a particle size range of 10 to 200 μm.

6. The method for preparing the cement strength stimulator according to claim 1, characterized in that The following steps are involved: The seed crystal accelerator, the polyol amine compound A, the cement kiln bypass vent ash and the modified lithium slag are mixed and stirred uniformly to obtain a cement strength activator.

7. Use of the cement strength stimulator according to claim 1 in a cement preparation process, characterized in that Including grinding together with other raw materials during the cement grinding process.

8. The use of the cement strength stimulator in the cement preparation process as claimed in claim 7, characterized in that The dosage of the cement strength stimulator is 0.3-0.5 wt% of the total mass of all raw materials in the cement grinding process.

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