阅读说明：本技术 一种液体速凝剂及其制备方法和应用 (Liquid accelerator and preparation method and application thereof ) 是由 徐忠洲 王英维 苗瑞文 于 2020-03-19 设计创作，主要内容包括：本发明公开了一种液体速凝剂及其制备方法。该液体速凝剂的制备原料包括：含有偏铝酸盐的溶液、硫酸铝、无机酸溶液、络合稳定剂、水,以及任选的防沉剂和酸度中和剂。本发明提供的液体低碱速凝剂在较低掺量下即具有水泥凝结硬化快、喷射混凝土早期强度发展迅速、后期强度基本无损失等优点,而且具有广泛的水泥适应性,即使对于C<Sub>3</Sub>A含量低的水泥仍能提供优良的快硬早强性能；该液体速凝剂无(低)腐蚀、长期存放性能稳定,且生产工艺简单,条件易控,具有良好的经济效益和广阔的应用前景。(The invention discloses a liquid accelerator and a preparation method thereof. The liquid accelerator comprises the following raw materials: the aluminum sulfate-containing solution comprises a solution of metaaluminate, aluminum sulfate, an inorganic acid solution, a complexing stabilizer, water and an optional anti-settling agent and an acidity neutralizer. The liquid low-alkali accelerating agent provided by the invention has the advantages of quick cement setting and hardening, quick development of early strength of sprayed concrete, basically no loss of later strength and the like under a lower mixing amount, and has wide cement adaptability even for C 3 The cement with low A content can still provide excellent quick-hardening early-strength performance; the liquid accelerator has no (low) corrosion, stable long-term storage performance, simple production process, easily-controlled conditions and good economic benefitAnd wide application prospect.)

1. A liquid accelerator is prepared from the following raw materials: the aluminum sulfate-containing solution comprises a solution of metaaluminate, aluminum sulfate, an inorganic acid solution, a complexing stabilizer, water and an optional anti-settling agent and an acidity neutralizer.

2. The liquid accelerator according to claim 1, wherein the amount of the solution containing meta-aluminate is 9 to 30 wt%, the amount of aluminum sulfate is 30 to 50 wt%, the amount of the inorganic acid solution is 10 to 30 wt%, the amount of the complex stabilizer is 1 to 5 wt%, the amount of water is 5 to 50 wt%, the amount of the anti-settling agent is 0 to 2 wt%, and the amount of the acidity neutralizer is 0 to 5 wt%, based on the total weight of the liquid accelerator;

preferably, in the inorganic acid solution, the concentration of the inorganic acid is 20 to 50 wt%;

preferably, the inorganic acid is selected from one or more of fluosilicic acid, hydrofluoric acid, sulfuric acid and phosphoric acid;

preferably, the complexing stabilizer is selected from one or more of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, citric acid, oxalic acid, tartaric acid, salicylic acid, lactic acid and EDTA;

preferably, the anti-settling agent is selected from one or more of attapulgite clay powder, bentonite, diatomite and hydrated magnesium silicate;

preferably, the acidity neutralising agent is magnesium oxide and/or magnesium hydroxide.

3. The liquid accelerator according to claim 1 or 2, wherein the raw material for preparing the solution containing the meta-aluminate comprises: alkali, aluminum hydroxide and water; preferably, the base is sodium hydroxide and/or potassium hydroxide;

preferably, the amount of base is 20-25 wt%, the amount of aluminium hydroxide is 25-35 wt% and the amount of water is 40-55 wt%, based on the total weight of the solution containing the meta-aluminate.

4. The liquid accelerator according to any one of claims 1 to 3, wherein the liquid accelerator has a pH of 2 to 4;

preferably, the mixing amount of the liquid accelerator ranges from 5 to 7 wt%.

5. A preparation method of a liquid accelerator comprises the following steps:

step 1, mixing a solution containing metaaluminate with water, adding aluminum sulfate for multiple times, and then carrying out first mixing to obtain a first mixture;

step 2, carrying out second mixing on the first mixture and a complexing stabilizer to obtain a second mixture;

step 3, adding an inorganic acid solution into the second mixture, and carrying out third mixing to obtain a third mixture;

and 4, optionally, carrying out fourth mixing on the third mixture with an anti-settling agent and an acidity neutralizing agent, and adjusting the pH value.

6. The method according to claim 5, wherein the preparation of the solution containing metaaluminate comprises: mixing alkali with water, heating, and mixing with aluminum hydroxide;

preferably, the heating temperature is 90-120 ℃;

preferably, the mixing reaction time is 2-4 h.

7. The method according to claim 5 or 6, wherein the plurality of times in step 1 is 2 to 5 times; preferably, stirring for 5-15min after each addition;

preferably, the time of the first mixing is 15-30 min.

8. The method according to any one of claims 5 to 7, wherein the time of the second mixing in step 2 is 15 to 45 min;

preferably, the inorganic acid is added in a dropwise manner in the step 3, and the adding time is 30-90 min;

preferably, the time of the third mixing is 30-60 min;

preferably, the time of the fourth mixing is 30-60 min;

preferably, the pH is 2 to 4.

9. A liquid accelerator prepared by the method of any one of claims 5 to 8.

10. Use of a liquid accelerator according to any one of claims 1 to 4 and 9 and/or prepared according to the method of any one of claims 5 to 8 in a building material.

Technical Field

The invention belongs to the field of building materials, and particularly relates to a liquid accelerator as well as a preparation method and application thereof.

Background

Along with the large-scale construction of projects such as traffic tunnels, mine roadway support, repair reinforcement, water resistance, leakage stoppage and the like, the accelerator with the rapid setting and hardening function becomes an indispensable additive for modern sprayed concrete.

At present, the liquid accelerator used for wet shotcrete is mainly an alkali accelerator and an alkali-free accelerator. The alkali accelerator has high alkali content generally, strong corrosivity easily causes harm to the bodies of construction personnel, and alkali aggregate reaction is easily caused by strong alkali characteristics, so that the later strength of concrete is obviously reduced, the impermeability grade is reduced, the durability of the concrete is influenced, and the construction of engineering is not facilitated; compared with an alkaline accelerator, the alkali-free liquid accelerator has the advantages of low corrosivity, high later strength, no adverse effect on the durability of concrete, capability of effectively reducing resilience and dust generation and the like, but the popularization and application of the alkali-free accelerator are limited by a series of problems of poor stability, high cost, high doping amount, low 1d compressive strength, poor cement adaptability and the like.

CN102219426A discloses a low-alkali liquid accelerator and a preparation method thereof. The low-alkali liquid accelerator is prepared by neutralizing an aluminum sulfate solution and a sodium aluminate solution to generate an aluminum hydroxide sol, and then polymerizing aluminum sulfate with the aluminum hydroxide sol in an original solution system to form polyaluminum sulfate, so that the accelerator solution has higher aluminum ion content and liquid stability; the low-alkali liquid accelerating agent is composed of aluminum sulfate, sodium aluminate and a stabilizer, and the mass percentages of the components are as follows: 40-60% of aluminum sulfate, 6-12% of sodium aluminate, 0-0.2% of stabilizer and the balance of water. However, the low-alkaline liquid accelerating agent disclosed by the patent needs to be heated to 60-80 ℃ for reaction, the energy consumption is high, and the phenomenon of gel aggregation and thickening is easily caused by the neutralization of a sodium aluminate solution and an aluminum sulfate solution to generate an aluminum hydroxide sol, so that the reaction progress and the solution stability are influenced.

Therefore, the development of the liquid accelerator with good stability, high cost performance, good accelerating effect and high early and later strength is of great significance.

Disclosure of Invention

Aiming at the technical problems, the invention provides a liquid accelerator, a preparation method and application thereof, and the accelerator has the advantages of quick cement setting and hardening and spray coagulation under a low mixing amountThe early strength of the soil is developed rapidly, the later strength is basically not lost, and the like, and the soil has wide cement adaptability even for C₃The cement with low A content can still provide excellent quick-hardening early-strength performance; the liquid accelerator has no (low) corrosion, stable long-term storage performance, no need of heating in the production process and simple production process.

The invention provides a liquid accelerator, which is prepared from the following raw materials: the aluminum sulfate-containing solution comprises a solution of metaaluminate, aluminum sulfate, an inorganic acid solution, a complexing stabilizer, water and an optional anti-settling agent and an acidity neutralizer.

According to some embodiments of the liquid accelerator according to the present invention, the meta-aluminate containing solution is used in an amount of 9 to 30 wt% based on the total weight of the liquid accelerator. Such as 9 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator of the present invention, aluminum sulfate is used in an amount of 30 to 60 wt% based on the total weight of the liquid accelerator. Such as 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator according to the present invention, the inorganic acid solution is used in an amount of 10 to 30 wt% based on the total weight of the liquid accelerator. Such as 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator according to the present invention, the complex stabilizer is used in an amount of 1 to 5 wt% based on the total weight of the liquid accelerator. Such as 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator of the present invention, water is used in an amount of 5 to 50 wt% based on the total weight of the liquid accelerator. Such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and any value therebetween. In the present invention, the amount of water used herein does not include the amount of water used in the solution containing metaaluminate and the inorganic acid solution.

According to some embodiments of the liquid accelerator according to the present invention, the anti-settling agent is used in an amount of 0 to 2 wt% based on the total weight of the liquid accelerator. Such as 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator of the present invention, the acidity neutralizer is used in an amount of 0 to 5 wt% based on the total weight of the liquid accelerator. Such as 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator of the invention, the aluminum sulfate may be analytically pure aluminum sulfate or industrial aluminum sulfate, and Al₂O₃The content is more than or equal to 15.6wt percent. In view of economic cost, preferred are industrial aluminum sulfate, and Al₂O₃The content is more than or equal to 15.6wt percent.

According to some embodiments of the liquid accelerator of the invention, the solute of the inorganic acid solution is an inorganic acid, and the solvent is water. In the inorganic acid solution, the concentration of the inorganic acid is 20 to 50 wt%.

According to some embodiments of the liquid accelerator of the invention, the inorganic acid is selected from one or more of fluorosilicic acid, hydrofluoric acid, sulfuric acid, and phosphoric acid.

According to some embodiments of the liquid accelerator of the invention, the complexing stabilizer is selected from one or more of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, citric acid, oxalic acid, tartaric acid, salicylic acid, lactic acid and EDTA.

According to some embodiments of the liquid accelerator of the invention, the anti-settling agent is selected from one or more of attapulgite clay powder, bentonite, diatomaceous earth and hydrous magnesium silicate.

According to some embodiments of the liquid accelerator of the invention, the acidity neutralizer is magnesium oxide and/or magnesium hydroxide.

According to some embodiments of the liquid accelerator of the present invention, the starting material for preparing the solution containing meta-aluminate comprises: alkali, aluminum hydroxide and water. Preferably, the base is sodium hydroxide and/or potassium hydroxide.

According to some embodiments of the liquid accelerator according to the present invention, the alkali is used in an amount of 20 to 25 wt% based on the total weight of the solution containing meta-aluminate. Such as 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator according to the present invention, the aluminum hydroxide is used in an amount of 25 to 35 wt% based on the total weight of the solution containing meta-aluminate. Such as 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator according to the present invention, water is used in an amount of 40 to 55 wt% based on the total weight of the solution containing meta-aluminate. Such as 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, and any value therebetween.

According to some embodiments of the liquid accelerator of the invention, the pH of the liquid accelerator is 2 to 4.

According to some embodiments of the liquid accelerator of the present invention, the blending amount of the accelerator ranges from 5 to 7 wt%. Such as 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, and any value therebetween.

The invention provides a preparation method of a liquid accelerator, which comprises the following steps:

step 1, mixing a solution containing metaaluminate with water, adding aluminum sulfate for multiple times, and then carrying out first mixing to obtain a first mixture;

step 2, carrying out second mixing on the first mixture and a complexing stabilizer to obtain a second mixture;

step 3, adding an inorganic acid solution into the second mixture, and carrying out third mixing to obtain a third mixture;

and 4, optionally, carrying out fourth mixing on the third mixture with an anti-settling agent and an acidity neutralizing agent, and adjusting the pH value.

According to some embodiments of the preparation method of the present invention, the meta-aluminate containing solution is charged in an amount of 9 to 30 wt% based on the total weight of the liquid accelerator. Such as 9 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the aluminum sulfate is charged in an amount of 30 to 60 wt% based on the total weight of the liquid accelerator. Such as 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the inorganic acid solution is added in an amount of 10 to 30 wt% based on the total weight of the liquid accelerator. Such as 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the complex stabilizer is added in an amount of 1-5 wt% based on the total weight of the liquid accelerator. Such as 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and any value therebetween.

According to some embodiments of the method of the present invention, the amount of water is 5-50 wt% based on the total weight of the liquid accelerator. Such as 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, and any value therebetween. In the present invention, the amount of water used herein does not include the amount of water used in the solution containing metaaluminate and the inorganic acid solution.

According to some embodiments of the preparation method of the present invention, the anti-settling agent is added in an amount of 0 to 2 wt% based on the total weight of the liquid accelerator. Such as 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, and any value therebetween.

According to some embodiments of the method of preparing the acid neutralizer of the present invention, the acid neutralizer is added in an amount of 0 to 5 wt% based on the total weight of the liquid accelerator. Such as 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the aluminum sulfate may be analytically pure aluminum sulfate or industrial aluminum sulfate, and Al₂O₃The content is more than or equal to 15.6wt percent. In view of economic cost, preferred are industrial aluminum sulfate, and Al₂O₃The content is more than or equal to 15.6wt percent.

According to some embodiments of the method of the present invention, the solute of the inorganic acid solution is an inorganic acid and the solvent is water. In the inorganic acid solution, the concentration of the inorganic acid is 20 to 50 wt%.

According to some embodiments of the method of manufacturing of the present invention, the inorganic acid is selected from one or more of fluosilicic acid, hydrofluoric acid, sulfuric acid, and phosphoric acid.

According to some embodiments of the method of making of the present invention, the complexing stabilizer is selected from one or more of ethanolamine, diethanolamine, triethanolamine, triisopropanolamine, citric acid, oxalic acid, tartaric acid, salicylic acid, lactic acid, and EDTA.

According to some embodiments of the method of manufacturing of the present invention, the anti-settling agent is selected from one or more of attapulgite clay powder, bentonite, diatomaceous earth, and hydrous magnesium silicate.

According to some embodiments of the method of making of the present invention, the acidity neutralizer is magnesium oxide and/or magnesium hydroxide.

According to some embodiments of the method of preparing of the present invention, the starting materials for preparing the solution containing meta-aluminate comprise: alkali, aluminum hydroxide and water. Preferably, the base is sodium hydroxide and/or potassium hydroxide.

According to some embodiments of the method of preparing of the present invention, the method of preparing the solution containing meta-aluminate comprises: the alkali is mixed with water, heated and then mixed with aluminum hydroxide. Preferably, the heating temperature is 90-120 ℃. Preferably, the mixing time is 2-4 h. Preferably, the alkali, the aluminum hydroxide and the water are fed in a weight ratio such that the alkali is used in an amount of 20 to 25 wt%, the aluminum hydroxide is used in an amount of 25 to 35 wt% and the water is used in an amount of 40 to 55 wt%, based on the total weight of the solution containing the meta-aluminate.

According to some embodiments of the preparation method of the present invention, the plurality of times in step 1 is 2 to 5 times; preferably, each addition is followed by mixing for 5-15 min. For example, the required aluminum sulfate is divided into 5 parts, and each part is added and mixed for 5-15 min. The liquid accelerator prepared in the preferable adding times and the preferable mixing time after each adding has better effect.

According to some embodiments of the preparation method of the present invention, the time of the first mixing is 15 to 30 min. Namely, all the aluminum sulfate is added, and then the mixture is mixed and stirred for 15-30 min. The liquid setting accelerator prepared in the preferred first mixing time of the present invention has a good effect.

According to some embodiments of the method of manufacturing of the present invention, the time of the second mixing in step 2 is 15 to 45 min. The liquid setting accelerator prepared in the second mixing time preferred in the present invention has a good effect.

According to some embodiments of the preparation method of the present invention, the inorganic acid is added dropwise in step 3, and the addition time is 30-90 min. According to a preferred embodiment of the present invention, the inorganic acid solution is added dropwise to the second mixture over 30 to 90 min.

According to some embodiments of the preparation method of the present invention, the time of the third mixing is 30 to 60 min. The liquid setting accelerator prepared in the preferred third mixing time of the invention has better effect.

According to some embodiments of the preparation method of the present invention, the time of the fourth mixing is 30 to 60 min. The liquid setting accelerator prepared in the fourth mixing time preferred by the invention has better effect.

According to some embodiments of the method of manufacturing of the present invention, the pH is 2 to 4. The pH can be adjusted by adding an acidity neutralizer.

According to a preferred embodiment of the present invention, a method for preparing a liquid accelerator, comprises:

step 1, uniformly mixing a solution containing metaaluminate with water, adding aluminum sulfate for multiple times at intervals, stirring, mixing and reacting to obtain a first mixed solution;

step 2, adding a complexing stabilizer into the first mixed solution obtained in the step 1, and stirring, mixing and reacting to obtain a second mixed solution;

step 3, adding an inorganic acid solution into the second mixed solution obtained in the step 2, stirring, mixing and reacting to obtain a third mixed solution;

and 4, optionally, adding an anti-settling agent and/or an acidity agent neutralizer into the third mixed solution obtained in the step 3, stirring, mixing and reacting, and adjusting the pH value of the solution to obtain the liquid accelerator.

In a third aspect, the invention provides a liquid accelerator prepared by the above method.

According to some embodiments of the liquid accelerator of the invention, the pH of the liquid accelerator is 2 to 4.

According to some embodiments of the liquid accelerator of the invention, the blending amount of the liquid accelerator ranges from 5 to 7 wt%. Such as 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, and any value therebetween.

In a fourth aspect, the present invention provides the use of an accelerator as described above and/or an accelerator prepared according to the method described above in a building material.

Compared with the prior art, the invention has the beneficial effects that:

(1) the liquid low-alkali accelerating agent provided by the invention has high content of stable aluminum salt and low alkali content, so that the liquid low-alkali accelerating agent has the advantages of quick cement setting and hardening, quick development of early strength of sprayed concrete, basically no loss of later strength, low rebound rate, less dust and the like under lower mixing amountPoint and have wide cement adaptability even for C₃The cement with low A content can still provide excellent quick-hardening early-strength performance;

(2) the liquid low-alkali accelerator provided by the invention has the advantages of no (low) corrosion, good long-term storage stability, low viscosity and the like, has excellent comprehensive performance, and has obvious economic advantages;

(3) the preparation method of the liquid low-alkali accelerating agent provided by the invention has the advantages of simple production process, no need of heating in the whole production process, low energy consumption, contribution to production and popularization of products and wide application prospect.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention easier to understand, the present invention will be described in further detail with reference to the following examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[ example 1 ]

Step 1, mixing 44 parts by weight of sodium hydroxide with 96 parts by weight of deionized water, heating to 100 ℃, adding 60 parts by weight of aluminum hydroxide, and reacting for 3 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 210 parts by weight of deionized water and 200 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 420 parts by weight of industrial aluminum sulfate (140 parts by weight for each time) for 3 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 20min to obtain a first mixed solution;

step 3, adding 20 parts by weight of citric acid into the first mixed solution obtained in the step 2, and stirring and reacting for 30min to obtain a second mixed solution;

step 4, dripping 125 parts by weight of inorganic acid solution (the content of fluosilicic acid is 38 wt%, the content of hydrofluoric acid is 1.5 wt%, the content of sulfuric acid is 0.5 wt%, and the content of deionized water is 60 wt%) into the second mixed solution obtained in the step 3 within 30min, and stirring and reacting for 30min to obtain a third mixed solution;

and 5, sequentially adding 5 parts by weight of diatomite and 20 parts by weight of magnesium oxide into the third mixed solution obtained in the step 4, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid low-alkali accelerating agent with the pH value of 2.8.

[ example 2 ]

Step 1, mixing 62.5 parts by weight of sodium hydroxide and 100 parts by weight of deionized water, heating to 110 ℃, adding 87.5 parts by weight of aluminum hydroxide, and reacting for 2 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 140 parts by weight of deionized water and 250 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 400 parts by weight of industrial aluminum sulfate (100 parts by weight for each time) for 4 times, mixing and stirring for 10min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 15min to obtain a first mixed solution;

step 3, adding 20 parts by weight of diethanolamine into the first mixed solution obtained in the step 2, and stirring and reacting for 45min to obtain a second mixed solution;

step 4, dropwise adding 180 parts by weight of inorganic acid solution (the content of fluosilicic acid is 32.5 wt%, the content of phosphoric acid is 2 wt%, the content of sulfuric acid is 0.5 wt%, and the content of deionized water is 65 wt%) into the second mixed solution obtained in the step 3 within 60min, and stirring and reacting for 60min to obtain a third mixed solution;

and 5, adding 10 parts by weight of bentonite into the third mixed solution obtained in the step 4, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid low-alkali accelerator with the pH value of 3.2.

[ example 3 ]

Step 1, mixing 62.1 parts by weight of sodium hydroxide and 121.5 parts by weight of deionized water, heating to 120 ℃, adding 86.4 parts by weight of aluminum hydroxide, and reacting for 4 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 50 parts by weight of deionized water and 270 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 350 parts by weight of industrial aluminum sulfate (175 parts by weight in each time) in 2 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 20min to obtain a first mixed solution;

step 3, adding 15 parts by weight of triethanolamine into the first mixed solution obtained in the step 2, and stirring and reacting for 30min to obtain a second mixed solution;

step 4, dripping 300 parts by weight of inorganic acid solution (the content of fluosilicic acid is 21.5 wt%, the content of hydrofluoric acid is 2 wt%, the content of phosphoric acid is 1.5 wt%, and the content of deionized water is 75 wt%) into the second mixed solution obtained in the step 3 within 60min, and stirring and reacting for 30min to obtain a third mixed solution;

and 5, adding 15 parts by weight of magnesium oxide into the third mixed solution obtained in the step 4, stirring and reacting for 30min, and cooling to room temperature to obtain the liquid low-alkali accelerator with the pH value of 3.0.

[ example 4 ]

Step 1, mixing 69 parts by weight of sodium hydroxide and 135 parts by weight of deionized water, heating to 120 ℃, adding 96 parts by weight of aluminum hydroxide, and reacting for 4 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 80 parts by weight of deionized water and 300 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 350 parts by weight of industrial aluminum sulfate (150 parts by weight for the first time and 200 parts by weight for the second time) in 2 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 15min to obtain a first mixed solution;

step 3, adding 20 parts by weight of oxalic acid into the first mixed solution obtained in the step 2, and stirring and reacting for 30min to obtain a second mixed solution;

step 4, dripping 240 parts by weight of inorganic acid solution (the content of fluosilicic acid is 34.5 wt%, the content of hydrofluoric acid is 0.5 wt%, and the content of deionized water is 65 wt%) into the second mixed solution obtained in the step 3 within 45min, and stirring and reacting for 30min to obtain a third mixed solution;

and 5, adding 15 parts by weight of magnesium hydroxide into the third mixed solution obtained in the step 4, stirring for reacting for 45min, and cooling to room temperature to obtain the liquid low-alkali accelerator with the pH value of 3.5.

[ example 5 ]

Step 1, mixing 42.3 parts by weight of sodium hydroxide and 81.9 parts by weight of deionized water, heating to 100 ℃, adding 55.8 parts by weight of aluminum hydroxide, and reacting for 3 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 160 parts by weight of deionized water and 180 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 450 parts by weight of industrial aluminum sulfate (150 parts by weight each time) 3 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 15min to obtain a first mixed solution;

step 3, adding 25 parts by weight of diethanolamine into the first mixed solution obtained in the step 2, and stirring and reacting for 30min to obtain a second mixed solution;

step 4, dripping 175 parts by weight of inorganic acid solution (the content of fluosilicic acid is 29 wt%, the content of hydrofluoric acid is 0.5 wt%, the content of phosphoric acid is 0.5 wt%, and the content of deionized water is 70 wt%) into the second mixed solution obtained in the step 3 within 90min, and stirring and reacting for 30min to obtain a third mixed solution;

and 5, adding 10 parts by weight of attapulgite powder into the third mixed solution obtained in the step 4, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid low-alkali accelerator with the pH value of 2.5.

[ example 6 ]

Step 1, sequentially adding 210 parts by weight of deionized water and 200 parts by weight of a solution containing sodium metaaluminate (the weight of sodium metaaluminate powder is 63.5g, and the weight of water is 136.5g) into a reactor provided with a stirrer, uniformly stirring, adding 420 parts by weight of industrial aluminum sulfate (140 parts by weight for each time) for 3 times, mixing and stirring for 15min after each addition, and mixing and stirring for 20min after all the industrial aluminum sulfate is added to obtain a first mixed solution;

step 2, adding 20 parts by weight of citric acid into the first mixed solution obtained in the step 1, and stirring and reacting for 30min to obtain a second mixed solution;

step 3, dripping 125 parts by weight of inorganic acid solution (the content of fluosilicic acid is 38 wt%, the content of hydrofluoric acid is 1.5 wt%, the content of sulfuric acid is 0.5 wt%, and the content of deionized water is 60 wt%) into the second mixed solution obtained in the step 2 within 30min, and stirring and reacting for 30min to obtain a third mixed solution;

and 4, sequentially adding 5 parts by weight of diatomite and 20 parts by weight of magnesium oxide into the third mixed solution obtained in the step 3, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid accelerator with the pH value of 2.0.

Comparative example 1

Step 1, mixing 44 parts by weight of sodium hydroxide with 96 parts by weight of deionized water, heating to 100 ℃, adding 60 parts by weight of aluminum hydroxide, and reacting for 3 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 335 parts by weight of deionized water and 200 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 420 parts by weight of industrial aluminum sulfate (140 parts by weight for each time) for 3 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 20min to obtain a first mixed solution;

step 3, adding 20 parts by weight of citric acid into the first mixed solution obtained in the step 2, and stirring and reacting for 30min to obtain a second mixed solution;

and 4, sequentially adding 5 parts by weight of diatomite and 20 parts by weight of magnesium oxide into the second mixed solution obtained in the step 3, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid accelerator with the pH value of 4.7.

Comparative example 2

Step 1, mixing 44 parts by weight of sodium hydroxide with 96 parts by weight of deionized water, heating to 100 ℃, adding 60 parts by weight of aluminum hydroxide, and reacting for 3 hours to obtain a solution containing sodium metaaluminate;

step 2, sequentially adding 230 parts by weight of deionized water and 200 parts by weight of the solution containing sodium metaaluminate obtained in the step 1 into a reactor provided with a stirrer, uniformly stirring, adding 420 parts by weight of industrial aluminum sulfate (140 parts by weight for each time) for 3 times, mixing and stirring for 15min after each addition, adding all the industrial aluminum sulfate, mixing and stirring for 20min to obtain a first mixed solution;

step 3, dripping 125 parts by weight of inorganic acid solution (the content of fluosilicic acid is 38 wt%, the content of hydrofluoric acid is 1.5 wt%, the content of sulfuric acid is 0.5 wt%, and the content of deionized water is 60 wt%) into the first mixed solution obtained in the step 2 within 30min, and stirring and reacting for 30min to obtain a second mixed solution;

and 4, sequentially adding 5 parts by weight of diatomite and 20 parts by weight of magnesium oxide into the third mixed solution obtained in the step 3, stirring and reacting for 60min, and cooling to room temperature to obtain the liquid accelerator with the pH value of 3.5.

Comparative example 3

The commercially available liquid contains an alkali accelerator, and the main parameters of the product are as follows: density 1.52g/cm³The solid content was 51.8 wt%, the pH was 12.7, the alkali content was 24.5 wt%, and the chloride ion content was 0.05 wt%.

Comparative example 4

The commercial liquid alkali-free accelerator comprises the following main parameters: density 1.36g/cm³The solid content was 50.6 wt%, the pH was 2.3, the alkali content was 0.7 wt%, and the chloride ion content was 0.06 wt%.

Comparative example 5

The commercial liquid alkali-free accelerator comprises the following main parameters: density 1.42g/cm³The solid content was 47.5 wt%, the pH was 2.8, the alkali content was 0.4 wt%, and the chloride ion content was 0.05 wt%.

[ test example 1 ]

The performance indexes of the liquid accelerators in examples 1 to 6 and comparative examples 1 to 5 are detected according to the test method of related items of GB/T35159-2017 accelerator for sprayed concrete, and the specific detection results are shown in Table 1.

TABLE 1

As can be seen from the data in Table 1, the mortar of examples 1-5 has a retention rate of 28d compressive strength and 90d compressive strength which is significantly higher than that of the liquid alkali setting accelerator (comparative example 3), and has no or little loss of the later strength of the mortar; compared with the liquid alkali-free setting accelerator (comparative examples 4 and 5), the examples have obvious advantages in the aspects of stability, mixing amount, 1d compressive strength and the like, and when the mixing amount is in the range of 5-7 wt%, the cement paste is quickly set and hardened and the 1d compressive strength of the mortar is quickly developed.

As is clear from comparison between examples 1 and 6, in example 6 in which sodium metaaluminate powder was used as it is, the liquid quick-setting admixture obtained by the preferred production method of the present invention had advantages such as good storage stability, low admixture amount, rapid setting and hardening of neat mortar, and high compressive strength of mortar 1d, as compared with example 1 in which a solution containing metaaluminate was prepared by mixing alkali with water, heating and then reacting with aluminum hydroxide.

[ test example 2 ]

In order to fully understand the adaptability of the liquid low-alkali setting accelerator prepared by the invention to different brands of cement, kui kudong, conch, yao bo, red lion, dingxin, xinyi and huaxin brand p.o42.5 ordinary portland cement is respectively selected and the liquid low-alkali setting accelerator prepared in example 2 is adopted to carry out the detection of setting time and mortar strength, and the test results are shown in table 2.

TABLE 2

As can be seen from Table 2, the liquid low-alkali accelerating agent prepared by the invention can enable the net slurry setting time and the mortar strength of different brands of cement to meet the standard requirements of GB/T35159-2017 accelerating agent for sprayed concrete within the mixing amount range of 5-7 wt%, and has wide cement adaptability.

What has been described above is merely a preferred example of the present invention. It should be noted that other equivalent variations and modifications can be made by those skilled in the art based on the technical teaching provided by the present invention, and the protection scope of the present invention should be considered.