Alkali-free and fluoride-free liquid accelerator, preparation method and application thereof

Abstract

The application provides an alkali-free and fluoride-free liquid accelerator and a preparation method and application thereof, and relates to the technical field of admixtures for building materials. The alkali-free and fluoride-free liquid accelerator comprises the following components in percentage by mass: aluminum sulfate, 52-60%; aluminum hydroxide, 1-8%; hydroxyl carboxylic acid, 0.3-4%; alcohol amine, 4-12%; stabilizer, 1-5%; suspending agent, 0.3-1%; and the balance is water, supplemented to 100%. The alkali-free and fluoride-free liquid accelerator has a stability of >120 days under the condition of 20-25 DEG C and a stability of >30 days under the condition of -5 DEG C, can meet the technical requirements of Q / CR 807-2020 'Liquid alkali-free accelerator for tunnel shotcrete' when used in cement paste or cement mortar and mixed in an amount of 6-8%, has qualified setting time, a 6h compressive strength of >1MPa, a 1d compressive strength of >10MPa, a 28d compressive strength ratio of >90%, and a 90d compressive strength retention rate of >105%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of admixtures for building materials, and particularly relates to a liquid alkali-free and fluoride-free accelerator and a preparation method and application thereof. BACKGROUND

[0002] The accelerator for concrete refers to an admixture capable of rapidly hardening and solidifying concrete without excessively affecting the long-term strength of the concrete. The accelerator has an important influence on the time, strength and rebound of sprayed concrete. The incorporation of the accelerator can rapidly harden and solidify the sprayed concrete to form sufficient strength to meet the strength requirements of the tunnel supporting structure. Therefore, the performance of the accelerator is crucial to the performance and construction quality of the sprayed concrete.

[0003] At present, the commonly used accelerator for sprayed concrete generally contains a large amount of alkaline substances such as aluminate, silicate and carbonate. Although the accelerator can meet the demand for rapid hardening, it has a great influence on the late strength of the sprayed concrete. Meanwhile, a large amount of alkaline substances increases the alkali-aggregate reaction of the concrete in the later period, thereby damaging the durability of the concrete. In addition, the problems of large rebound of the concrete and strong corrosion exist. Therefore, most of the accelerators that can meet the market demand are alkali-free and fluoride-free accelerators.

[0004] However, since the main coagulation component of the alkali-free and fluoride-free accelerator is aluminum ions, the aluminum ions will hydrolyze and precipitate when reacting in an aqueous solution, thereby causing crystallization and precipitation, which affects the stability of the accelerator. Once the crystallization and precipitation occur during storage, an irreversible delamination phenomenon will directly affect the performance of the accelerator, and the phenomenon of pipe blockage is prone to occur during the construction of the sprayed concrete. Therefore, in order to ensure the stability of the alkali-free and fluoride-free accelerator, the aluminum content of the commonly used alkali-free and fluoride-free accelerator in the market is relatively low, so that the early strength of the prepared concrete is low, which cannot meet the needs of projects that require early strength. Therefore, it has become a technical problem to be solved in the field to prepare an alkali-free and fluoride-free accelerator with good stability and high early strength. SUMMARY

[0005] (I) Technical problems to be solved

[0006] In view of the deficiencies in the prior art, the present application provides a liquid alkali-free and fluoride-free accelerator and a preparation method and application thereof.

[0007] (II) Technical solutions

[0008] To achieve the above object, the present application is implemented by the following technical solutions:

[0009] The liquid alkali-free and fluoride-free accelerator comprises the following components in mass percentage:

[0010]

[0011] Preferably, the composition comprises the following components in the following mass percentages:

[0012]

[0013] Preferably, the alcohol amine is diethanolamine, content > 99%.

[0014] Preferably, the aluminum sulfate is industrial grade aluminum sulfate octadecahydrate, the content of aluminum oxide in the aluminum sulfate is > 15.8%, the aluminum sulfate is in the form of flakes or powder; the aluminum hydroxide is industrial grade, content > 99%, particle size > 800 mesh.

[0015] Preferably, the hydroxyl carboxylic acid is one or more of lactic acid, citric acid, and tannic acid.

[0016] Preferably, the suspending agent is hydrated magnesium silicate.

[0017] Preferably, the stabilizer comprises the following components in the following mass percentages:

[0018]

[0019] Preferably, the method for preparing the stabilizer comprises the following steps:

[0020] (1) heat the dimethyl ethanolamine and gluconic acid lactone to 60-80°C to prepare a reaction solution;

[0021] (2) after adding the ethanolamine into the reaction solution dropwise within 0.5-1h, continue to heat and react for 2-4h;

[0022] (3) add the tributyl phosphate, water, and hydroxyethyl cellulose in sequence, and stir until uniform, to obtain the stabilizer.

[0023] In another aspect, a method for preparing an alkali-free and fluoride-free liquid accelerator comprises the following steps:

[0024] (1) add the water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent, and aluminum sulfate into a reaction vessel in sequence, and shear at a linear velocity of 40-200m / s for 1-2h without heat source;

[0025] (2) add the alcohol amine and stabilizer, and continue to shear at a linear velocity of 40-200m / s for 2h, to obtain the alkali-free and fluoride-free liquid accelerator.

[0026] In another aspect, the alkali-free and fluoride-free liquid accelerator is used in the preparation of shotcrete.

[0027] (III) Beneficial effects

[0028] The application provides an alkali-free and fluoride-free liquid accelerator and a preparation method and application thereof.

[0029] 1. The alkali-free and fluoride-free liquid accelerator disclosed in the application comprises a stabilizer, and the stabilizer comprises dimethyl ethanolamine, gluconic acid lactone, ethanolamine, hydroxyethyl cellulose and tributyl phosphate. The dimethyl ethanolamine has good combination capacity as a surfactant, and esterification occurs with the gluconic acid lactone having a stabilizing effect under heating conditions to generate ester and water in the system. At this time, the ethanolamine is added to improve the activity of the system, and then the tributyl phosphate and the hydroxyethyl cellulose are added to thicken, suspend and emulsify the organic matter in the system, and finally a stabilizer having a complexing effect is formed to effectively complex the aluminum ions in the alkali-free and fluoride-free liquid accelerator, improve the activity of the aluminum ions, effectively ensure the stability of the accelerator system at room temperature and low temperature, and the addition of the stabilizer has no negative effect on the setting time and strength of the accelerator product.

[0030] 2. The alkali-free and fluoride-free liquid accelerator disclosed in the application further comprises a hydroxyl carboxylic acid and an alcohol amine, and the hydroxyl carboxylic acid and the alcohol amine play a protective role in the room temperature and low temperature stability of the alkali-free and fluoride-free liquid accelerator.

[0031] 3. The preparation method of the alkali-free and fluoride-free liquid accelerator comprises high-speed dispersion at a shear speed of 40 m / s-200 m / s. Under the triple stabilizing protection of the hydroxyl carboxylic acid, the diethanolamine and the stabilizer, the accelerator system is in a stable polymer state, and then the suspension agent hydrated magnesium silicate is added and uniformly dispersed in the solution under the action of high-speed dispersion to further uniformly disperse the aluminum ion polymer in the accelerator system, form a stable liquid system with high suspension and ultra-fine particles, effectively prevent the settlement and aggregation of the aluminum ions in the accelerator, and further ensure the room temperature and low temperature stability of the accelerator system.

[0032] 4. The alkali-free and fluoride-free liquid accelerator disclosed in the application comprises aluminum sulfate and aluminum hydroxide. On the one hand, a small amount of active aluminum hydroxide is added to effectively ensure the aluminum ion content in the system and improve the activity of the aluminum ions. On the other hand, in the alkali-free and fluoride-free liquid accelerator, the aluminum sulfate accounts for 52-60%, and the aluminum hydroxide accounts for 1-8%, the content of the coagulation component is high, the coagulation effect is good, the setting time is short, the prepared alkali-free and fluoride-free liquid accelerator has high early strength, 6h>1Mpa and 1d>10Mpa, can meet the detection standard of the iron standard Q / CR 807-2020 "Liquid alkali-free accelerator for tunnel shotcrete", and can meet the needs of projects requiring early strength.

[0033] Therefore, the alkali-free and fluoride-free liquid accelerator prepared in the application has the characteristics of fast setting time, high early strength, and good stability at room temperature and low temperature. Using the detection method of the accelerator in Q / CR 807-2020, the setting time is qualified, the 6h compressive strength is >1MPa, the 1d compressive strength is >10MPa, the 28d compressive strength ratio is >90%, and the 90d compressive strength retention rate is >105% within the dosage of 6-8%; the stability is >120 days at 20-25℃, and the stability is >30 days at-5℃, which can be used in wet spraying process of sprayed concrete, and is suitable for highway, coal mine, municipal engineering, and especially for mountain tunnel engineering and railway engineering in harsh environment. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application is described clearly and completely. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0035] The embodiments of the application provide an alkali-free and fluoride-free liquid accelerator, a preparation method and application thereof, and solve the technical problems of poor stability and low early strength of the alkali-free and fluoride-free accelerator used in the current market.

[0036] The technical scheme in the embodiments of the application is to solve the above technical problems, and the general idea is as follows:

[0037] Since the solubility of aluminum sulfate is only about 36g-40g at 20℃-30℃, on the basis of no heat source, by increasing the content of aluminum sulfate in the accelerator system, the aluminum ion precipitation and solidification phenomenon is easy to occur, which leads to the destruction of the system stability; and the application effectively prepares the stabilizer and uses the high-speed dispersion process to prepare the alkali-free and fluoride-free liquid accelerator, which not only increases the content of aluminum sulfate to ensure the early strength, but also effectively ensures the system stability of the alkali-free and fluoride-free liquid accelerator at room temperature and low temperature.

[0038] The present application does not select the conventional preparation method commonly used at present in the preparation process, but uses high-speed dispersion preparation at a linear speed of 40-200 m / s. Under the triple stabilizing protection of hydroxyl carboxylic acid, diethanolamine and stabilizer, the accelerator system is in a stable polymer state. By adding hydrated magnesium silicate as a suspending agent and under the action of high-speed dispersion, the suspending agent is uniformly dispersed in the solution, further uniformly dispersing the aluminum ion polymer in the accelerator system, forming a stable liquid system with ultra-fine particles and high suspension, which can flow, effectively preventing the settlement and aggregation of aluminum ions in the accelerator, and further ensuring the room temperature and low temperature stability of the accelerator system.

[0039] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific embodiments.

[0040] Example 1

[0041] This example provides a kind of alkali-free fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0042] Among them, the proportion of stabilizer is as follows: dimethyl ethanolamine 20%; gluconic acid lactone 5%; ethanolamine 3%; hydroxyethyl cellulose 2%; tributyl phosphate 0.1%; the balance is water.

[0043] The preparation method of the stabilizer is as follows:

[0044] (1) dimethyl ethanolamine and gluconic acid lactone are heated to 60 DEG C, and are prepared into reaction solution;

[0045] (2) after adding ethanolamine into the reaction solution dropwise within 0.5h, continue to keep warm for 2h;

[0046] (3) add tributyl phosphate, water and hydroxyethyl cellulose in turn, and stir uniformly, to obtain the stabilizer.

[0047] The preparation method of the alkali-free fluoride-free liquid accelerator is as follows:

[0048] (1) water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent and aluminum sulfate are sequentially added into a reaction container, and are high-speed sheared at a linear speed of 40 m / s without heat source for 1h;

[0049] (2) add alcohol amine and stabilizer, and continue to shear at a linear speed of 40 m / s for 2h, to obtain the alkali-free fluoride-free liquid accelerator.

[0050] Example 2

[0051] This example provides a kind of alkali-free fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0052] The proportion of the stabilizer is as follows: dimethyl ethanolamine 25%; gluconic acid lactone 7%; ethanolamine 4%; hydroxyethyl cellulose 3%; tributyl phosphate 0.2%; and the balance is water.

[0053] The preparation method of the stabilizer is as follows:

[0054] (1) dimethyl ethanolamine and gluconic acid lactone are heated to 65 DEG C to prepare a reaction solution;

[0055] (2) ethanolamine is added dropwise into the reaction solution within 0.6 h, and the reaction is continued for 2.5 h;

[0056] (3) tributyl phosphate, water and hydroxyethyl cellulose are added successively, and stirred uniformly to obtain the stabilizer.

[0057] The preparation method of the alkali-free and fluoride-free liquid accelerator is as follows:

[0058] (1) water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent and aluminum sulfate are added successively into a reaction container, and sheared at a linear velocity of 45 m / s for 1.1 h under the condition of no heat source;

[0059] (2) alcohol amine and stabilizer are added, and sheared at a linear velocity of 45 m / s for 2 h to obtain the alkali-free and fluoride-free liquid accelerator.

[0060] Example 3

[0061] The alkali-free and fluoride-free liquid accelerator provided in the example has the proportion shown in Table 1.

[0062] The proportion of the stabilizer is as follows: dimethyl ethanolamine 25%; gluconic acid lactone 7%; ethanolamine 4%; hydroxyethyl cellulose 3%; tributyl phosphate 0.2%; and the balance is water.

[0063] The preparation method of the stabilizer is as follows:

[0064] (1) dimethyl ethanolamine and gluconic acid lactone are heated to 65 DEG C to prepare a reaction solution;

[0065] (2) ethanolamine is added dropwise into the reaction solution within 0.6 h, and the reaction is continued for 2.5 h;

[0066] (3) tributyl phosphate, water and hydroxyethyl cellulose are added successively, and stirred uniformly to obtain the stabilizer.

[0067] The preparation method of the alkali-free and fluoride-free liquid accelerator is as follows:

[0068] (1) water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent and aluminum sulfate are added successively into a reaction container, and sheared at a linear velocity of 45 m / s for 1.1 h under the condition of no heat source;

[0069] (2) add alcohol amine and stabilizer, continue shearing at linear velocity of 100 for 2h, to obtain the alkali-free and fluoride-free liquid accelerator.

[0070] Example 4

[0071] This example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0072] The proportion of the stabilizer is as follows: dimethyl ethanolamine 35%; gluconic acid lactone 8%; ethanolamine 5%; hydroxyethyl cellulose 7%; tributyl phosphate 0.4%; and the balance is water.

[0073] The preparation method of the stabilizer is as follows:

[0074] (1) heat dimethyl ethanolamine and gluconic acid lactone to 75℃, and prepare a reaction solution;

[0075] (2) after adding ethanolamine into the reaction solution dropwise within 0.8h, continue to heat for 3.5h;

[0076] (3) add tributyl phosphate, water and hydroxyethyl cellulose in sequence, and stir uniformly, to obtain the stabilizer.

[0077] The preparation method of the alkali-free and fluoride-free liquid accelerator is as follows:

[0078] (1) add water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent and aluminum sulfate into a reaction container in sequence, and shear at a linear velocity of 150m / s under the condition of no heat source for 1.8h;

[0079] (2) add alcohol amine and stabilizer, continue shearing at a linear velocity of 180m / s for 2h, to obtain the alkali-free and fluoride-free liquid accelerator.

[0080] Example 5

[0081] This example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0082] The proportion of the stabilizer is as follows: dimethyl ethanolamine 40%; gluconic acid lactone 10%; ethanolamine 6%; hydroxyethyl cellulose 8%; tributyl phosphate 0.5%; and the balance is water.

[0083] The preparation method of the stabilizer is as follows:

[0084] (1) heat dimethyl ethanolamine and gluconic acid lactone to 80℃, and prepare a reaction solution;

[0085] (2) after adding ethanolamine into the reaction solution dropwise within 1h, continue to heat for 4h;

[0086] (3) add tributyl phosphate, water, hydroxyethyl cellulose in turn, stir uniformly, and the stabilizer is obtained.

[0087] The preparation method of the alkali-free and fluoride-free liquid accelerator is as follows:

[0088] (1) add water, hydroxyl carboxylic acid, aluminum hydroxide, suspending agent, and aluminum sulfate in turn into a reaction container, and shear at a linear velocity of 200 m / s for 2 hours under the condition of no heat source;

[0089] (2) add alcohol amine and stabilizer, and continue to shear at a linear velocity of 200 m / s for 2 hours, and the alkali-free and fluoride-free liquid accelerator is obtained.

[0090] Comparative Example 1

[0091] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportioning is shown in Table 1.

[0092] The proportioning of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0093] Comparative Example 2

[0094] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportioning is shown in Table 1.

[0095] The proportioning of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0096] Comparative Example 3

[0097] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportioning is shown in Table 1.

[0098] The proportioning of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0099] Comparative Example 4

[0100] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportioning is shown in Table 1.

[0101] The proportioning of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0102] Comparative Example 5

[0103] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportioning is shown in Table 1.

[0104] The proportioning of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0105] Comparative Example 6

[0106] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0107] The proportion of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0108] Comparative Example 7

[0109] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0110] The preparation method of the alkali-free and fluoride-free liquid accelerator is the same as that in Example 3.

[0111] Comparative Example 8

[0112] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0113] The proportion of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0114] Comparative Example 9

[0115] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0116] The proportion of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0117] Comparative Example 10

[0118] The comparative example provides an alkali-free and fluoride-free liquid accelerator, and the proportion is shown in Table 1.

[0119] The proportion of the stabilizer, the preparation method of the stabilizer, and the preparation method of the alkali-free and fluoride-free liquid accelerator are the same as those in Example 3.

[0120] Test Example

[0121] The accelerators prepared in Examples 1-5 and Comparative Examples 1-10 are added into cement paste or cement mortar in an amount of 6-8% of the weight of cement according to the standards of GB / T 35159-2017 “Accelerator for Shotcrete” and Q / CR 807-2020 “Liquid Alkali-Free Accelerator for Tunnel Shotcrete”, and the setting time and compressive strength are tested, and the stability of the accelerator at room temperature and low temperature is tested.

[0122] The reference cement is the cement produced by Fushun Cement Co., Ltd. within the effective period; the sand is the Chinese ISO standard sand produced by Xiamen Aiseo Standard Sand Co., Ltd.

[0123] The test conditions are: temperature 20℃, humidity 55%, the mortar test block is molded and cured in a standard curing box to the corresponding age, and then the compressive strength test is conducted.

[0124] The cement paste setting time test ratio is: reference cement: water = 400: 140.

[0125] The cement mortar compressive strength test ratio is: reference cement: standard sand: water = 900: 1350: 450.

[0126] The above water includes the water in the accelerator, and the amount of water in the accelerator is deducted according to the actual solid content of the accelerator when preparing.

[0127] The above test results are shown in Tables 2-4.

[0128] Table 1: The component ratio of each component of Examples 1-5 and Comparative Examples 1-10

[0129]

[0130]

[0131] Table 2: The cement paste setting time and mortar strength test results of Examples 1-5 and Comparative Examples 1-10

[0132]

[0133]

[0134] Table 3: The normal temperature stability test results of the accelerator of Examples 1-5 and Comparative Examples 1-10

[0135]

[0136]

[0137] Table 4: The low temperature stability test results of the accelerator of Examples 1-5 and Comparative Examples 1-10

[0138]

[0139] From Table 2, compared with Example 3, the non-alkali and non-fluorine accelerator without adding aluminum hydroxide has long setting time of neat paste, low 6h and 1d compressive strength of mortar. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 4% of hydroxyl carboxylic acid has lower 6h and 1d compressive strength of mortar. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with less than 4% of alcohol amine has long setting time of mortar. Compared with Example 1, the non-alkali and non-fluorine accelerator with more than 12% of alcohol amine has short setting time of neat paste, increased 6h and 1d compressive strength of mortar, but greatly reduced stability. Compared with Example 3, the non-alkali and non-fluorine accelerator with adding stabilizer has no effect on setting time of neat paste, 6h and 1d compressive strength of mortar.

[0140] From Table 3 and 4, compared with Example 3, the non-alkali and non-fluorine accelerator without adding hydroxyl carboxylic acid has poor stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 8% of aluminum hydroxide has poor stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 4% of hydroxyl carboxylic acid has poor stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with less than 4% of alcohol amine has reduced stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 12% of alcohol amine has reduced stability at normal and low temperature. Compared with Example 3, the non-alkali and non-fluorine accelerator without adding stabilizer has poor stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 5% of stabilizer has reduced stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with less than 0.3% of suspending agent has reduced stability at normal and low temperature. Compared with Example 1-5, the non-alkali and non-fluorine accelerator with more than 1% of suspending agent has reduced stability at normal and low temperature.

[0141] It is to be noted that, in the present text, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0142] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit the present application; even though the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An alkali-free and fluorine-free liquid quick-setting agent, characterized in that, Components include the following percentage by weight: Aluminum sulfate 52-60%; Aluminum hydroxide 1-8%; Hydroxycarboxylic acids 0.3-4%; Alkylamines 4-12%; Stabilizer 1-5%; Suspension agent 0.3-1%; The remaining amount is water; replenish to 100%. The stabilizer comprises the following components by mass percentage: Dimethylethanolamine 20-40%; Gluconolactone 5-10%; ethanolamine 3-6%; Hydroxyethyl cellulose 2-8%; Tributyl phosphate 0.1-0.5%; The remainder is water.

2. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1, characterized in that, Components include the following percentage by weight: Aluminum sulfate 54-59%; Aluminum hydroxide 2-6%; Hydroxycarboxylic acids 2-3%; Alkylamines 5-10%; Stabilizer 2-4%; Suspension agent 0.5-0.8%; The remainder is water; add water to bring the total to 100%.

3. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1 or 2, characterized in that, The alcohol amine is diethanolamine, with a content ≥99%.

4. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1 or 2, characterized in that, The aluminum sulfate is industrial grade aluminum sulfate octahydrate, the aluminum oxide content in the aluminum sulfate is ≥15.8%, and the aluminum sulfate is in flake or powder form; the aluminum hydroxide is industrial grade, with a content ≥99% and a particle size ≥800 mesh.

5. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1 or 2, characterized in that, The hydroxycarboxylic acid is at least one of lactic acid, citric acid, and tannic acid.

6. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1 or 2, characterized in that, The suspending agent is hydrated magnesium silicate.

7. The alkali-free and fluorine-free liquid quick-setting agent as described in claim 1, characterized in that, The method for preparing the stabilizer includes the following steps: (1) The dimethylethanolamine and gluconolactone are heated to 60-80°C to prepare a reaction solution; (2) After adding ethanolamine dropwise into the reaction solution within 0.5-1h, continue to keep the reaction at the temperature for 2-4h; (3) Add the tributyl phosphate, water and hydroxyethyl cellulose in sequence, and stir until uniform to obtain the stabilizer.

8. A method for preparing an alkali-free and fluorine-free liquid quick-setting agent according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Add water, hydroxycarboxylic acid, aluminum hydroxide, suspending agent and aluminum sulfate to the reaction vessel in sequence, and shear at a high speed of 40m / s-200m / s for 1-2 hours without heat source; (2) Add alcohol amine and stabilizer, and continue shearing at a shear rate of 40m / s-200m / s for 2 hours to obtain the alkali-free and fluorine-free liquid quick-setting agent.

9. The application of the alkali-free and fluorine-free liquid quick-setting agent according to any one of claims 1-7 in the preparation of shotcrete.

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