Aluminum sulfate type early high-strength alkali-free liquid accelerator and preparation method thereof

Abstract

This invention discloses an aluminum sulfate-based early-setting, high-strength, alkali-free liquid accelerator and its preparation method, relating to the technical field of concrete admixtures and accelerators. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid accelerator of this invention is composed of the following raw materials in the indicated mass percentages: magnesium silicate 0.8%~1.2%, aluminum sulfate 57%~61%, an alkanolamine complexing agent 9%~11%, modified aluminum dihydrogen phosphate emulsion 1.4%~1.8%, a pH adjuster 1%~1.4%, and the balance being water. This invention, through the synergistic effect of multiple components, increases the effective aluminum sulfate content in the accelerator while avoiding the adverse effects of excessive alkali content. The final product is a supersaturated aluminum sulfate solution with high early and late strength retention rates, good stability, and a shelf life of over 4 months at room temperature. Furthermore, the raw material cost of this accelerator is low, the production process and conditions are convenient, and it has good adaptability to different cement types.

Description

Technical Field

[0001] This invention relates to the field of concrete admixtures and accelerators, and particularly to an aluminum sulfate-based early high-strength alkali-free liquid accelerator and its preparation method. Background Technology

[0002] As a type of admixture for shotcrete, the main function of quick-setting agents is to promote the rapid setting and hardening of cement and significantly improve its early strength. These additives are usually composed of a variety of chemical components and play a role by regulating the cement hydration reaction rate and strength development process.

[0003] Accelerators can be classified into powder and liquid forms based on their physical form. Due to the significant advantages of wet spraying, liquid accelerators have become the current development direction of accelerator technology. Based on the content of alkaline substances, they can be classified into alkali-containing and alkali-free types. Among them, when the alkali content calculated in sodium oxide equivalent is less than 1.0%, the accelerator is defined as alkali-free. Based on the main accelerating components, they can be classified into alumina clinker type, alkali metal carbonate type, silicate type, aluminum sulfate type, etc.

[0004] Among them, aluminum sulfate-based liquid accelerators have become the mainstream choice among inorganic accelerators due to their rapid setting, uniform strength, low cost, and good environmental performance. However, aluminum sulfate-based liquid accelerator products on the market generally have some obvious quality differences. The main problems include: low early strength due to insufficient hydration reaction, low later strength retention rate due to excessive alkaline content, and unstable state due to high aluminum sulfate content.

[0005] Therefore, how to accelerate the early hydration rate, balance the relationship between the content of alkaline components and the later strength retention rate, and extend the shelf life of the product under high aluminum sulfate dosage have become urgent problems to be solved. Developing a liquid accelerator with aluminum sulfate as the main accelerator component, which has the characteristics of being alkaline-free, having high early strength and high stability, has great engineering practical significance. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide an aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent and its preparation method.

[0007] The technical solution adopted in this invention is as follows:

[0008] An aluminum sulfate-based early-strength, alkali-free liquid quick-setting agent is composed of the following raw materials in the indicated mass percentages: magnesium silicate 0.8%~1.2%, aluminum sulfate 57%~61%, alkanolamine complexing agent 9%~11%, modified aluminum dihydrogen phosphate emulsion 1.4%~1.8%, pH adjuster 1%~1.4%, and the balance being water.

[0009] The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent of this invention uses the above-mentioned raw material composition and ratio: the core component, aluminum sulfate, releases Al after dissolving. 3+ SO4 2- It reacts rapidly with C3A and early hydration products Ca(OH)2 in cement to generate a large number of needle-like ettringite that interweaves into a three-dimensional framework, promoting rapid initial setting and simultaneously facilitating the hydration of C3S to generate high-strength CSH gel. Among the amine complexing agents, the amino group can reduce the activation energy of the C3A reaction and catalyze rapid setting, while the hydroxyl group can react with Ca... 2+ Al 3+ The formation of complexes prevents flash solidification caused by excessively rapid reactions, and the slow decomposition of the complexes in the later stages allows for sustained strength development. The suspension system formed by magnesium silicate dissolving in water increases the crystallization resistance of aluminum sulfate, making the product more stable, and also allows for the slow release of SiO3 in acidic environments. 2- , with Ca 2+ The reaction produces fine hydrated magnesium silicate gel, which fills the pores of the ettringite framework and improves density; in the modified aluminum dihydrogen phosphate emulsion, aluminum dihydrogen phosphate reacts with Ca in the cement system. 2+ The reaction produces high-strength calcium phosphate and calcium aluminum phosphate, and can also react with Al. 3+ Multinuclear complexes are formed to prevent aluminum sulfate crystallization. Hydroxypropyl methylcellulose is used to maintain emulsion stability, indirectly improving overall stability. Acrylamide and aminotrimethylene phosphonic acid can form a flexible polymer network through weak polymerization in this system, strengthening the interfacial bond between cement paste and aggregate. A pH adjuster buffers the system pH to a weakly acidic range of 4.0-5.0 through ionization equilibrium, preventing precipitation from aluminum sulfate hydrolysis and avoiding excessive acidity that inhibits cement hydration. Its carboxyl groups can also help disperse cement particles. Water, as a pure solvent, ensures uniform dissolution or dispersion of all components, controls the system viscosity to suit construction flowability, and deionized water is preferred to avoid sodium... + Cl - The introduction of impurities can lead to the formation of latent alkalis or cause steel reinforcement corrosion. Therefore, the aluminum sulfate-based early high-strength alkali-free liquid accelerator provided by this invention achieves efficient rapid setting and performance balance of concrete under alkali-free conditions through multi-component synergy.

[0010] Preferably, the aluminum sulfate is industrial grade aluminum sulfate with a mass fraction ≥85%.

[0011] Preferably, the magnesium silicate has a mass fraction of ≥98%.

[0012] Preferably, the amine complexing agent is a mixture of diethanolamine and triethanolamine, wherein the diethanolamine accounts for 60% to 80% of the total mass of the amines in the mixture.

[0013] Preferably, the modified aluminum dihydrogen phosphate emulsion comprises, by mass percentage: 44%~46% aluminum dihydrogen phosphate, 0.12%~0.20% dispersant, 6%~8% acrylamide, and 0.5%~0.9% aminotrimethylenephosphonic acid.

[0014] Preferably, the dispersant is hydroxypropyl methylcellulose.

[0015] Further preferably, the preparation method of the modified aluminum dihydrogen phosphate emulsion includes the following steps:

[0016] a. Heat the water to 65℃, add aluminum dihydrogen phosphate evenly to the water, and stir for 20 minutes;

[0017] b. Slowly add the dispersant dropwise to the solution in a, and stir for 5 minutes after the addition is complete;

[0018] c. Add acrylamide and aminotrimethylenephosphonic acid, and stir for 10 minutes.

[0019] Further preferably, the pH adjuster is one of lactic acid and citric acid.

[0020] This invention also provides a method for preparing the above-mentioned aluminum sulfate-based early high-strength alkali-free liquid quick-setting agent, comprising the following steps:

[0021] S1. Weigh each component raw material according to its mass percentage and set aside.

[0022] S2. Add magnesium silicate to water and stir for 10 minutes;

[0023] S3. Divide aluminum sulfate into three equal parts and add them in batches, with an interval of 20 minutes between each addition. After adding all of them, stir for 60 minutes.

[0024] S4. Add an alcohol amine complexing agent and continue stirring until completely dissolved;

[0025] S5. Add modified aluminum dihydrogen phosphate emulsion and stir for 20 minutes;

[0026] S6. Add pH adjuster and stir for 10 minutes to prepare aluminum sulfate type early high strength alkali-free liquid quick-setting agent.

[0027] Preferably, in steps S3 to S6, the reaction temperature is 50 to 60°C.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. In the modified aluminum dihydrogen phosphate emulsion of the present invention, aluminum dihydrogen phosphate and Ca... 2+ A reaction occurs, producing high-strength calcium phosphate and calcium aluminum phosphate, which react with Al. 3+The combination forms a multinucleated complex, effectively preventing aluminum sulfate crystallization. Hydroxypropyl methylcellulose can improve emulsion stability. Acrylamide and aminotrimethylene phosphonic acid help form a flexible polymer network in the reaction system of cement and accelerator, strengthening the interfacial bond between cement paste and aggregate. The 6-hour compressive strength ratio can be greater than 200% (the 6-hour compressive strength of concrete mortar without the addition is 1.51 MPa), and the 1-day compressive strength ratio can be greater than 150% (the 1-day compressive strength of concrete mortar without the addition is 11.8 MPa).

[0030] 2. The raw materials of this invention do not contain alkali metal ions, which is friendly to construction workers and is a pollution-free green product. It prevents the risk of alkali-aggregate reaction and results in a high strength retention rate in the later stage. When using appropriate raw material ratios, the 90-day retention rate can be greater than 100%.

[0031] 3. This invention utilizes the synergistic effect of multiple components, including magnesium silicate, alkanolamine complexing agents, modified aluminum dihydrogen phosphate emulsion, and pH adjusters, to inhibit the precipitation caused by aluminum sulfate hydrolysis, increase the crystallization resistance of aluminum sulfate, and improve the effective aluminum sulfate content in the quick-setting agent. The final product is a supersaturated solution with an aluminum sulfate content as high as 57%~61%, and it has good stability and can be stored at room temperature for more than 4 months.

[0032] 4. The raw material cost of this invention is low, the production process is simple and easy to operate, and the reaction conditions are mild, without the need for special conditions such as high temperature and high pressure, making it suitable for large-scale industrial production applications. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] Example 1

[0035] The modified aluminum dihydrogen phosphate emulsion was prepared as follows: 450g aluminum dihydrogen phosphate; 1.6g hydroxypropyl methylcellulose; 70g acrylamide; 7g aminotrimethylenephosphonic acid; and 478.4g water. 478.4g water was added to a 2L reactor, and stirring was started at 250rpm. The reactor jacket was heated to 65℃ with a temperature control accuracy of ±1℃. 450g aluminum dihydrogen phosphate was added, and stirring was carried out for 20 minutes. 1.6g hydroxypropyl methylcellulose was slowly added dropwise at a rate of 1mL / min, and stirring was continued for 5 minutes after the addition was complete. Acrylamide and aminotrimethylenephosphonic acid were added, and stirring was carried out for 10 minutes. Heating was then turned off, and the mixture was allowed to cool naturally to room temperature, finally yielding a white, dispersed modified aluminum dihydrogen phosphate emulsion.

[0036] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 10g magnesium silicate; 590g aluminum sulfate; 100g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 16g modified aluminum dihydrogen phosphate emulsion; 12g pH adjuster (lactic acid); and 272g water.

[0037] The preparation method of aluminum sulfate-based high-strength alkali-free liquid quick-setting agent is as follows: Pulverize aluminum sulfate to a particle size ≤0.1mm to avoid clumping; pre-mix the modified aluminum dihydrogen phosphate emulsion to ensure uniform solute dispersion; add 272g of water to a 2L reactor, start stirring at 250rpm, add 10g of magnesium silicate, and stir at room temperature for 10 minutes until the solution is uniformly suspended and no magnesium silicate settles to the bottom; heat the reactor jacket to 55℃ with a temperature control accuracy of ±1℃; add 590g of aluminum sulfate in three batches of 196.7g each, with a 20-minute interval between each batch; after all the aluminum sulfate has been added, continue stirring for 60 minutes, maintaining the temperature during this period. The mixture was kept at 55℃ until the aluminum sulfate was completely dissolved, the solution was clear, and there were no white flocculent substances. 100g of an alkanolamine complexing agent was added to the reactor and stirred continuously for more than 30 minutes at a speed of 250 rpm. The complexing agent was visually confirmed to be completely dissolved, and the solution was free of stratification and oily scum. 16g of modified aluminum dihydrogen phosphate emulsion was added to the reactor and stirred for another 20 minutes. Finally, 12g of lactic acid was slowly added dropwise at a rate of 1mL / min, and the mixture was stirred for 10 minutes after the addition was completed. The heating was turned off and the mixture was allowed to cool naturally to room temperature. The final product was a pale yellow, transparent aluminum sulfate-based high-strength, alkali-free liquid quick-setting agent.

[0038] Example 2

[0039] The preparation method of the modified aluminum dihydrogen phosphate emulsion in this embodiment is the same as that in Example 1;

[0040] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 12g magnesium silicate; 610g aluminum sulfate; 110g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 18g modified aluminum dihydrogen phosphate emulsion; 14g pH adjuster (citric acid); and 236g water.

[0041] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid quick-setting agent in this embodiment is the same as that in Example 1, except that the heating reaction temperature in this embodiment is 60°C. A light brown transparent solution is finally obtained, with no crystallization occurring under supersaturated aluminum sulfate conditions.

[0042] Example 3

[0043] The preparation method of the modified aluminum dihydrogen phosphate emulsion in this embodiment is the same as that in Example 1;

[0044] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 570g aluminum sulfate; 8g magnesium silicate; 90g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 14g modified aluminum dihydrogen phosphate emulsion; 10g pH adjuster (lactic acid); and 308g water.

[0045] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid quick-setting agent in this embodiment is the same as that in Example 1, except that the heating reaction temperature in this embodiment is 50°C. A pale yellow transparent solution is finally obtained, with no crystallization occurring under supersaturated aluminum sulfate conditions.

[0046] Example 4

[0047] The preparation method of the modified aluminum dihydrogen phosphate emulsion in this embodiment is the same as that in Example 1;

[0048] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 590g aluminum sulfate; 10g magnesium silicate; 100g alkanolamine complexing agent (diethanolamine:triethanolamine=6:4); 16g modified aluminum dihydrogen phosphate emulsion; 12g pH adjuster (lactic acid); and 272g water.

[0049] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this embodiment is the same as that in Example 1. A pale yellow, transparent solution was finally prepared, with no crystallization occurring under supersaturated aluminum sulfate conditions.

[0050] Comparative Example 1

[0051] The preparation method of the modified aluminum dihydrogen phosphate emulsion in this comparative example is the same as that in Example 1;

[0052] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: magnesium silicate not added; aluminum sulfate 590g; alkanolamine complexing agent (diethanolamine:triethanolamine=8:2) 100g; modified aluminum dihydrogen phosphate emulsion 16g; pH adjuster (lactic acid) 12g; water 282g.

[0053] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this comparative example is the same as that in Example 1. The final solution is yellow and turbid, and a small amount of precipitate appears after 3 days of storage.

[0054] Comparative Example 2

[0055] The preparation method of the modified aluminum dihydrogen phosphate emulsion in this comparative example is the same as that in Example 1;

[0056] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: pH adjuster (hydrochloric acid, industrial grade, concentration 37%) 12g; aluminum sulfate 590g; magnesium silicate 10g; alkanolamine complexing agent (diethanolamine:triethanolamine=8:2) 100g; modified aluminum dihydrogen phosphate emulsion 16g; water 272g.

[0057] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this comparative example is the same as that in Example 1. A blocky precipitate appeared in the final solution and could not be completely dissolved subsequently.

[0058] Comparative Example 3

[0059] The modified aluminum dihydrogen phosphate emulsion was prepared as follows: 450g aluminum dihydrogen phosphate; 70g acrylamide; 7g aminotrimethylenephosphonic acid; 478.4g water. 478.4g water was added to a 2L reactor, and stirring was started at 250rpm. The reactor jacket was heated to 65℃ with a temperature control accuracy of ±1℃. 450g aluminum dihydrogen phosphate was added, and stirring was carried out for 20 minutes. Acrylamide and aminotrimethylenephosphonic acid were then added, and stirring was carried out for 10 minutes. Heating was then turned off, and the mixture was allowed to cool naturally to room temperature. Since hydroxypropyl methylcellulose was not added, a white modified aluminum dihydrogen phosphate turbidity was finally obtained.

[0060] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 590g aluminum sulfate; 10g magnesium silicate; 100g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 12g pH adjuster (lactic acid); 16g modified aluminum dihydrogen phosphate emulsion; and 288g water.

[0061] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this comparative example is the same as that in Example 1. Plate-like crystals appeared in the final solution and could not be completely dissolved subsequently.

[0062] Comparative Example 4

[0063] The modified aluminum dihydrogen phosphate emulsion was prepared as follows: 450g aluminum dihydrogen phosphate; 1.6g hydroxypropyl methylcellulose; 478.4g water. 478.4g water was added to a 2L reactor, and stirring was started at 250rpm. The reactor jacket was heated to 65℃ with a temperature control accuracy of ±1℃. 450g aluminum dihydrogen phosphate was added, and stirring was carried out for 20 minutes. 1.6g hydroxypropyl methylcellulose was slowly added dropwise at a rate of 1mL / min. After the addition was complete, stirring was carried out for 5 minutes. Heating was then turned off, and the mixture was allowed to cool naturally to room temperature. Since no acrylamide or aminotrimethylenephosphonic acid was added, a transparent and dispersed modified aluminum dihydrogen phosphate solution was finally obtained.

[0064] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: 590g aluminum sulfate; 10g magnesium silicate; 100g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 12g pH adjuster (lactic acid); 16g modified aluminum dihydrogen phosphate emulsion; and 288g water.

[0065] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this comparative example is the same as that in Example 1. A pale yellow, transparent solution was finally obtained, with no crystallization occurring under supersaturated aluminum sulfate conditions.

[0066] Comparative Example 5

[0067] The raw materials for aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent are: unmodified aluminum dihydrogen phosphate emulsion; 590g aluminum sulfate; 10g magnesium silicate; 100g alkanolamine complexing agent (diethanolamine:triethanolamine=8:2); 12g pH adjuster (lactic acid); and 288g water.

[0068] The preparation method of the aluminum sulfate-based early high-strength alkali-free liquid accelerator in this comparative example is the same as that in Example 1. A pale yellow transparent solution was finally obtained, and a small amount of white aluminum sulfate crystals appeared after one month of storage.

[0069] To verify the performance and function of the aluminum sulfate-based early high-strength alkali-free liquid accelerators prepared in Examples 1-4 and Comparative Examples 1-5, they were added at 8% of the cement mass, and their performance was tested. The test results are shown in Table 1.

[0070] The solid content test and pH value determination method for alkali-free liquid quick-setting agents shall be performed in accordance with GB / T 8077-2012 "Test Method for Homogeneity of Concrete Admixtures".

[0071] The initial setting time, final setting time, 6-hour compressive strength, 1-day compressive strength, 28-day compressive strength ratio, and 90-day compressive strength retention rate of alkali-free liquid quick-setting agent were tested according to Appendix D and F of GB / T35159-2017 "Quick-setting Agents for Shotcrete". The tests included various types of cement, including the reference cement.

[0072] The stability test method for alkali-free liquid accelerators shall be performed in accordance with Appendix C of GB / T35159-2017 "Accelerators for Shotcrete", and the stratification values ​​shall be obtained after being placed at room temperature for 28d, 60d, 90d and 120d.

[0073] Table 1. Product performance test results of Examples 1-4 and Comparative Examples 1-5

[0074]

[0075] As shown in Table 1: When the aluminum sulfate-type early high-strength alkali-free liquid accelerator and the amine complexing agent in this invention are within the specified ratio range, the product can meet the Q / CR standard regardless of whether the other raw materials are in the median, upper limit, or lower limit ratio. The invention meets the requirements of the 807-2020 standard "Liquid Alkali-Free Accelerating Agent for Shotcrete in Tunnels" and achieves the target technical effect. Comparative Example 1 demonstrates that the absence of magnesium silicate significantly reduces the long-term strength retention rate and storage stability of the alkali-free liquid accelerating agent. Comparative Example 2 demonstrates that the rapid change in solution pH after using other pH adjusters can significantly prolong the setting time and reduce early strength, and the resulting aluminum sulfate precipitation also significantly affects storage stability. Comparative Examples 3-5 demonstrate that the absence of modified aluminum dihydrogen phosphate emulsion or the absence of corresponding suspension and polymer components in the modified aluminum dihydrogen phosphate emulsion results in one or more significant decreases in the setting time, early strength, long-term strength retention rate, and storage stability of the alkali-free liquid accelerating agent. This further verifies that the synergistic effect of modified aluminum dihydrogen phosphate emulsion with aluminum sulfate, magnesium silicate, and alkanolamine complexing agents is the key to the technical breakthrough achieved by this invention.

[0076] To verify the effect of the aluminum sulfate-based early high-strength alkali-free liquid accelerator of this invention on the adaptability to different cement types, P·O 42.5 ordinary Portland cement (including Conch, Huaxin, Zhonglian, and Nanfang brands) was used. The product prepared in Example 1 was used to test its initial setting time, final setting time, 6-hour compressive strength, 1-day compressive strength, 28-day compressive strength ratio, and 90-day compressive strength retention rate. The test methods were consistent with those used in the performance tests. The test results are shown in Table 2.

[0077] Table 2. Compatibility of aluminum sulfate-based high-strength alkali-free liquid accelerators with different cement types.

[0078]

[0079] As shown in Table 2, the dosage of aluminum sulfate type early high strength alkali-free liquid accelerator is between 6% and 8%. All four types of cement can meet the qualified product requirements in Q / CR 807-2020 "Liquid Alkali-Free Accelerator for Shotcrete in Tunnels", indicating that the aluminum sulfate type early high strength alkali-free liquid accelerator of this invention has good adaptability to cement types.

[0080] This specification is intended to be illustrative rather than restrictive. Based on this invention, those skilled in the art can make substitutions and modifications to some of the technical features without creative effort, and all such modifications are within the scope of protection of this invention.

Claims

1. An aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent, characterized in that, It is composed of the following raw materials in the following mass percentages: magnesium silicate 0.8%~1.2%, aluminum sulfate 57%~61%, alkanolamine complexing agent 9%~11%, modified aluminum dihydrogen phosphate emulsion 1.4%~1.8%, pH adjuster 1%~1.4%, and the balance is water.

2. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 1, characterized in that, The aluminum sulfate mentioned is industrial grade aluminum sulfate with a mass fraction ≥85%.

3. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 1, characterized in that, The magnesium silicate mass fraction is ≥98%.

4. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 1, characterized in that, The alkanolamine complexing agent is a mixture of diethanolamine and triethanolamine, wherein diethanolamine accounts for 60% to 80% of the total mass of alkanolamines in the mixture.

5. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 1, characterized in that, The modified aluminum dihydrogen phosphate emulsion comprises, by weight percentage: 44%~46% aluminum dihydrogen phosphate, 0.12%~0.20% dispersant, 6%~8% acrylamide, and 0.5%~0.9% aminotrimethylenephosphonic acid.

6. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 5, characterized in that, The dispersant is hydroxypropyl methylcellulose.

7. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 5, characterized in that, The preparation method of the modified aluminum dihydrogen phosphate emulsion includes the following steps: a. Heat the water to 65℃, add aluminum dihydrogen phosphate evenly to the water, and stir for 20 minutes; b. Slowly add the dispersant dropwise to the solution in a, and stir for 5 minutes after the addition is complete; c. Add acrylamide and aminotrimethylenephosphonic acid, and stir for 10 minutes.

8. The aluminum sulfate-based early-setting, high-strength, alkali-free liquid quick-setting agent according to claim 1, characterized in that, The pH adjuster is either lactic acid or citric acid.

9. The preparation method of the aluminum sulfate-type early high-strength alkali-free liquid quick-setting agent according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Weigh each component raw material according to its mass percentage and set aside. S2. Add magnesium silicate to water and stir for 10 minutes; S3. Divide aluminum sulfate into three equal parts and add them in batches, with an interval of 20 minutes between each addition. After adding all of them, stir for 60 minutes. S4. Add an alcohol amine complexing agent and continue stirring until completely dissolved; S5. Add modified aluminum dihydrogen phosphate emulsion and stir for 20 minutes; S6. Add pH adjuster and stir for 10 minutes to prepare aluminum sulfate type early high strength alkali-free liquid quick-setting agent.

10. The preparation method according to claim 9, characterized in that, In S3~S6, the reaction temperature is 50~60℃.

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