阅读说明：本技术 一种低碱速凝剂及其制备方法和应用 (Low-alkali accelerator and preparation method and application thereof ) 是由 李连震 王宏维 王英维 于 2020-05-18 设计创作，主要内容包括：本发明公开了一种低碱速凝剂及其制备方法。该低碱速凝剂的制备原料包括：硫酸铝、偏铝酸钠、氟硅酸镁、氢氟酸、三乙醇胺、稳定剂、无机改性材料和水。制备方法包括：步骤1、硫酸铝I、偏铝酸钠和水I进行混合,得到溶液I；步骤2、依次将氟硅酸镁和氢氟酸加入至所述溶液I中,得到溶液II；步骤3、将硫酸铝II、水II和所述溶液II进行混合,得到溶液III；步骤4、将硫酸铝III、三乙醇胺、稳定剂、无机改性材料和所述溶液III进行混合。本发明的低碱速凝具有较好的低温稳定性,在低温下依然具有较短的凝结硬化时间和较好的强度。(The invention discloses a low-alkali setting accelerator and a preparation method thereof. The low-alkali accelerator comprises the following raw materials: aluminum sulfate, sodium metaaluminate, magnesium fluosilicate, hydrofluoric acid, triethanolamine, a stabilizer, an inorganic modified material and water. The preparation method comprises the following steps: step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I; step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II; step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III; and 4, mixing aluminum sulfate III, triethanolamine, a stabilizer, an inorganic modified material and the solution III. The low-alkali quick setting agent has better low-temperature stability, and still has shorter setting and hardening time and better strength at low temperature.)

1. A low-alkali accelerator is prepared from the following raw materials: aluminum sulfate, sodium metaaluminate, magnesium fluosilicate, hydrofluoric acid, triethanolamine, a stabilizer, an inorganic modified material and water.

2. The low-alkali accelerator as claimed in claim 1, wherein the amount of aluminum sulfate is 30-40 wt%, the amount of sodium metaaluminate is 10-17 wt%, the amount of magnesium fluorosilicate is 10-15 wt%, the amount of hydrofluoric acid is 15-23 wt%, the amount of triethanolamine is 10-15 wt%, the amount of stabilizer is 0.5-1 wt%, the amount of inorganic modifier is 5-10 wt%, and the amount of water is 8-20 wt%, based on the total weight of the low-alkali accelerator.

3. The low-alkali accelerator according to claim 1 or 2, wherein the stabilizer is one or more selected from magnesium silicate, hydroxymethyl cellulose, hydroxyethyl cellulose and EDTA.

4. The low-alkali accelerator according to any one of claims 1 to 3, wherein the size of the inorganic modifier is 1 to 100 nm.

5. The low-alkali accelerator according to any one of claims 1 to 4, wherein the inorganic modified material is selected from one or more of sericite, talc and nano silica.

6. A preparation method of a low-alkali accelerator comprises the following steps:

step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III;

and 4, mixing aluminum sulfate III, triethanolamine, a stabilizer, an inorganic modified material and the solution III.

7. The method as claimed in claim 6, wherein the aluminum sulfate I, the aluminum sulfate II and the aluminum sulfate III are each independently used in an amount of 20 to 40% by weight based on the total weight of the aluminum sulfate, and the total amount of the aluminum sulfate is 30 to 40% by weight based on the total weight of the low alkali accelerator.

8. The method according to claim 6 or 7, wherein the amount of water I and water II is 30 to 70 wt% of the total amount of water, and the total amount of water is 8 to 20 wt% of the total weight of the low alkali accelerator.

9. A low alkali accelerator prepared by the method of any one of claims 6 to 8.

10. Use of a low alkali accelerator according to any one of claims 1 to 5 and 9 or prepared according to the method of any one of claims 6 to 8 in infrastructure construction.

Technical Field

The invention relates to a low-alkali accelerator and a preparation method and application thereof.

Background

The accelerator is an indispensable additional auxiliary agent in the construction of sprayed concrete, can quickly set and harden the concrete, and can reach certain strength in a short time to meet engineering requirements. Most of the accelerators sold on the market at present are alkali accelerators with the alkali content of more than or equal to 18 weight percent, the alkali content of the low-alkali accelerators is more than or equal to 6 weight percent and less than 18 weight percent, and the alkali accelerators have influence on the environment and the health of people to different degrees, and the research on the alkali-free or low-alkali accelerators is to find alkali metal new materials which can be replaced, so the low-alkali or alkali-free accelerators can be accepted on the market and are widely applied. In severe cold areas in the north in winter, the accelerator is easy to crystallize and freeze in the transportation and construction processes to generate frozen blocks, the frozen blocks lose the effect under the action of expansion stress, and the strength of concrete is greatly reduced. However, the existing low-alkali accelerating agent has the problems of poor low-temperature performance, poor low-temperature stability and high viscosity, and is not easy to carry out later-stage site construction.

Disclosure of Invention

Aiming at the technical problems, the invention provides a low-alkali accelerator, a preparation method and an application thereof.

The invention provides a low-alkali accelerator, which is prepared from the following raw materials: aluminum sulfate, sodium metaaluminate, magnesium fluosilicate, hydrofluoric acid, triethanolamine, a stabilizer, an inorganic modified material and water.

In the present invention, the low-alkali accelerator means an accelerator having an alkali content of not less than 6% by weight and less than 18% by weight.

According to some embodiments of the low alkali accelerator of the present invention, aluminum sulfate is used in an amount of 30 to 40% by weight, based on the total weight of the low alkali accelerator. Such as 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, and any value therebetween.

According to some embodiments of the low alkali accelerator of the present invention, sodium metaaluminate is used in an amount of 10 to 17% by weight, based on the total weight of the low alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, and any value therebetween.

According to some embodiments of the low-alkali accelerator according to the present invention, the amount of the magnesium silicofluoride is 10 to 15% by weight based on the total weight of the low-alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and any value therebetween.

According to some embodiments of the low alkali accelerator according to the present invention, hydrofluoric acid is used in an amount of 15 to 23 wt% based on the total weight of the low alkali accelerator. Such as 15, 16, 17, 18, 19, 20, 21, 22, 23 wt%, and any value therebetween.

According to some embodiments of the low alkali accelerator according to the present invention, triethanolamine is used in an amount of 10 to 15 wt% based on the total weight of the low alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and any value therebetween.

According to some embodiments of the low alkali accelerator of the present invention, the stabilizer is used in an amount of 0.5 to 1% by weight, based on the total weight of the low alkali accelerator. Such as 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, and any value therebetween.

According to some embodiments of the low alkali accelerator of the present invention, the inorganic modifying material is used in an amount of 5 to 10% by weight, based on the total weight of the low alkali accelerator. Such as 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, and any value therebetween.

According to some embodiments of the low alkali accelerator of the present invention, water is used in an amount of 8 to 20% by weight, based on the total weight of the low alkali accelerator. Such as 8 wt%, 10 wt%, 15 wt%, 20 wt%, and any value therebetween. In the present invention, the water may be deionized water.

According to some embodiments of the low alkali accelerator of the invention, the stabilizer is selected from one or more of magnesium silicate, hydroxymethyl cellulose, hydroxyethyl cellulose and EDTA (ethylenediaminetetraacetic acid).

According to some embodiments of the low-alkali accelerator of the invention, the inorganic modifying material has a size of 1 to 100 nm. The size is a sieve size.

According to some embodiments of the low-alkali accelerator of the present invention, the inorganic modification material is selected from one or more of sericite, talc and nano silica.

The invention provides a preparation method of a low-alkali accelerator, which comprises the following steps:

step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III;

and 4, mixing aluminum sulfate III, triethanolamine, a stabilizer, an inorganic modified material and the solution III.

According to some embodiments of the preparation method of the present invention, aluminum sulfate I, aluminum sulfate II, and aluminum sulfate III are each independently used in an amount of 20 to 40% by weight of the total amount of aluminum sulfate, and the total amount of aluminum sulfate is 30 to 40% by weight of the total weight of the low-alkali accelerator.

According to some embodiments of the preparation method of the present invention, water I and water II are each independently used in an amount of 30 to 70 wt% of the total amount of water, and the total amount of water is 8 to 20 wt% of the total weight of the low alkali accelerator.

According to some embodiments of the preparation method of the present invention, preferably, after step 1 and before step 2, the method further comprises stirring, more preferably, stirring for 10-20 min.

According to some embodiments of the preparation method of the present invention, preferably, after step 2 and before step 3, the method further comprises stirring, more preferably, stirring for 20-30 min.

According to some embodiments of the preparation method of the present invention, preferably, after step 4, the method further comprises stirring, more preferably, stirring for 2 to 3 hours.

According to some embodiments of the preparation method of the present invention, the aluminum sulfate is used in an amount of 30 to 40% by weight, based on the total weight of the low alkali accelerator. Such as 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, and any value therebetween.

According to some embodiments of the preparation method of the present invention, sodium metaaluminate is used in an amount of 10 to 17% by weight, based on the total weight of the low alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the magnesium silicofluoride is used in an amount of 10 to 15% by weight based on the total weight of the low alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the hydrofluoric acid is used in an amount of 15 to 23 wt% based on the total weight of the low alkali accelerator. Such as 15, 16, 17, 18, 19, 20, 21, 22, 23 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, triethanolamine is used in an amount of 10 to 15 wt% based on the total weight of the low alkali accelerator. Such as 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the stabilizer is used in an amount of 0.5 to 1% by weight, based on the total weight of the low alkali accelerator. Such as 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the inorganic modifying material is used in an amount of 5 to 10% by weight, based on the total weight of the low alkali accelerator. Such as 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, and any value therebetween.

According to some embodiments of the preparation method of the present invention, the water is used in an amount of 8 to 20% by weight, based on the total weight of the low alkali accelerator. Such as 8 wt%, 10 wt%, 15 wt%, 20 wt%, and any value therebetween. In the present invention, the water may be deionized water.

According to some embodiments of the method of making of the present invention, the stabilizer is selected from one or more of hydroxymethylcellulose, hydroxyethylcellulose and EDTA.

According to some embodiments of the method of preparing of the present invention, the inorganic modification material has a size of 1 to 100 nm.

According to some embodiments of the method of preparing of the present invention, the inorganic modification material is selected from one or more of sericite, talc and nano silica.

The third aspect of the present invention provides a low alkali accelerator prepared by the above method.

The invention provides the application of the low-alkali accelerating agent or the low-alkali accelerating agent prepared by the method in the infrastructure construction.

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

(1) compared with the existing accelerator, the accelerator disclosed by the invention has the advantages of low alkali content, no harm to a human body, low viscosity and convenience in field construction.

(2) Compared with the existing low-alkali accelerating agent, the low-alkali accelerating agent disclosed by the invention has the advantages that the stability can be kept for a long time at a lower temperature (for example, -15 ℃), the cement is quickly set and hardened, the early-stage strength and the later-stage strength can meet the engineering construction requirements, and the like.

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 aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, hydroxymethyl cellulose (stabilizer), sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

Wherein, the total amount of aluminum sulfate is 33 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 11 wt%, the amount of aluminum sulfate II is 11 wt%, and the amount of aluminum sulfate III is 11 wt%; 12% of sodium metaaluminate, 11% of magnesium fluosilicate, 15% of hydrofluoric acid, 13% of triethanolamine, 1% of stabilizer, 5% of inorganic modifying material and 10% of water, wherein the amount of water I is 5% by weight and the amount of water II is 5% by weight.

[ example 2 ]

The procedure of example 1 was followed except that sericite having a size of 50nm was replaced with talc having a size of 100 nm.

[ example 3 ]

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, hydroxyethyl cellulose (stabilizer), sericite (inorganic modified material with the size of 5nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

Wherein, the total amount of aluminum sulfate is 40 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 12 wt%, the amount of aluminum sulfate II is 16 wt%, and the amount of aluminum sulfate III is 12 wt%; the content of sodium metaaluminate is 10 wt%, the content of magnesium fluosilicate is 10 wt%, the content of hydrofluoric acid is 15 wt%, the content of triethanolamine is 10 wt%, the content of stabilizer is 0.5 wt%, the content of inorganic modifying material is 6.5 wt%, and the total content of water is 8 wt%, wherein the content of water I is 4 wt%, and the content of water II is 4 wt%.

[ example 4 ]

Step 1, mixing aluminum sulfate, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing the water II with the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

Wherein, the use amount of the aluminum sulfate is 33 percent by weight based on the total weight of the low-alkali accelerating agent; 12% of sodium metaaluminate, 11% of magnesium fluosilicate, 15% of hydrofluoric acid, 13% of triethanolamine, 1% of stabilizer, 5% of inorganic modifying material and 10% of water, wherein the amount of water I is 5% by weight and the amount of water II is 5% by weight.

[ example 5 ]

Step 1, mixing sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

The low-alkali accelerating agent comprises a low-alkali accelerating agent, a stabilizer, an inorganic modifying material and water, wherein the low-alkali accelerating agent is composed of 33 wt% of aluminum sulfate, 12 wt% of sodium metaaluminate, 11 wt% of magnesium fluosilicate, 15 wt% of hydrofluoric acid, 13 wt% of triethanolamine, 1 wt% of the stabilizer, 5 wt% of the inorganic modifying material and 10 wt% of the water, wherein the total weight of the low-alkali accelerating agent is taken as a reference, the amount of the aluminum sulfate is 33 wt%, the amount of the sodium metaaluminate is 12 wt%, the amount of the magnesium fluosilicate is 11 wt%, the amount of the hydrofluoric acid is 15.

[ example 6 ]

Step 1, mixing sodium metaaluminate and water I to obtain a solution I, and stirring for 20 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

and 3, mixing the water II, aluminum sulfate, triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution II, and stirring for 2 hours to obtain the low-alkali accelerating agent.

The low-alkali accelerating agent comprises a low-alkali accelerating agent, a stabilizer, an inorganic modifying material and water, wherein the low-alkali accelerating agent is composed of 33 wt% of aluminum sulfate, 12 wt% of sodium metaaluminate, 11 wt% of magnesium fluosilicate, 15 wt% of hydrofluoric acid, 13 wt% of triethanolamine, 1 wt% of the stabilizer, 5 wt% of the inorganic modifying material and 10 wt% of the water, wherein the total weight of the low-alkali accelerating agent is taken as a reference, the amount of the aluminum sulfate is 33 wt%, the amount of the sodium metaaluminate is 12 wt%, the amount of the magnesium fluosilicate is 11 wt%, the amount of the hydrofluoric acid is 15.

[ example 7 ]

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

Wherein, the total amount of aluminum sulfate is 24 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 8 wt%, the amount of aluminum sulfate II is 8 wt%, and the amount of aluminum sulfate III is 8 wt%; the content of sodium metaaluminate is 20 wt%, the content of magnesium fluosilicate is 15 wt%, the content of hydrofluoric acid is 21 wt%, the content of triethanolamine is 8 wt%, the content of stabilizer is 1 wt%, the content of inorganic modifying material is 5 wt%, and the total content of water is 6 wt%, wherein the content of water I is 3 wt%, and the content of water II is 3 wt%.

[ example 8 ]

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 1 h;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the low-alkali accelerating agent.

Wherein, the total amount of aluminum sulfate is 50 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 15 wt%, the amount of aluminum sulfate II is 20 wt%, and the amount of aluminum sulfate III is 15 wt%; the content of sodium metaaluminate is 5 wt%, the content of magnesium fluosilicate is 5 wt%, the content of hydrofluoric acid is 10 wt%, the content of triethanolamine is 5 wt%, the content of stabilizer is 1 wt%, the content of inorganic modifying material is 5 wt%, and the total content of water is 19 wt%, wherein the content of water I is 9 wt%, and the content of water II is 10 wt%.

Comparative example 1

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, adding hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, hydroxymethyl cellulose, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the accelerator.

Wherein, the total amount of aluminum sulfate is 37 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 12.33 wt%, the amount of aluminum sulfate II is 12.33 wt%, and the amount of aluminum sulfate III is 12.33 wt%; 13.5 percent by weight of sodium metaaluminate, 17 percent by weight of hydrofluoric acid, 14.6 percent by weight of triethanolamine, 1.1 percent by weight of stabilizer, 5.6 percent by weight of inorganic modifying material and 11.2 percent by weight of water, wherein the amount of water I is 5.6 percent by weight and the amount of water II is 5.6 percent by weight.

Comparative example 2

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing aluminum sulfate III, triethanolamine, sericite (inorganic modified material with the size of 50nm) and the solution III, and stirring for 2 hours to obtain the accelerator.

Wherein, the total amount of aluminum sulfate is 33 wt% based on the total weight of the low-alkali accelerator, wherein the amount of aluminum sulfate I is 11 wt%, the amount of aluminum sulfate II is 11 wt%, and the amount of aluminum sulfate III is 11 wt%; 12% of sodium metaaluminate, 11% of magnesium fluosilicate, 15% of hydrofluoric acid, 13% of triethanolamine, 6% of inorganic modification material and 10% of water, wherein the amount of water I is 5% by weight and the amount of water II is 5% by weight.

Comparative example 3

Step 1, mixing aluminum sulfate I, sodium metaaluminate and water I to obtain a solution I, and stirring for 10 min;

step 2, sequentially adding magnesium fluosilicate and hydrofluoric acid into the solution I to obtain a solution II, and stirring for 20 min;

step 3, mixing aluminum sulfate II, water II and the solution II to obtain a solution III, and stirring for 20 min;

and 4, mixing the aluminum sulfate III, the triethanolamine, the hydroxymethyl cellulose and the solution III, and stirring for 2 hours to obtain the accelerator.

Wherein, the total dosage of aluminum sulfate is 34.7 percent by weight based on the total weight of the low-alkali accelerator, wherein the dosage of aluminum sulfate I is 11.56 percent by weight, the dosage of aluminum sulfate II is 11.56 percent by weight, and the dosage of aluminum sulfate III is 11.56 percent by weight; 12.6 percent by weight of sodium metaaluminate, 11.6 percent by weight of magnesium fluosilicate, 15.8 percent by weight of hydrofluoric acid, 13.7 percent by weight of triethanolamine, 1.1 percent by weight of stabilizer and 10.5 percent by weight of water, wherein the amount of water I is 5.25 percent by weight and the amount of water II is 5.25 percent by weight.

Comparative example 4

A commercially available low alkali accelerator is available from Jie materials, Inc. of Guizhou, under the designation Point-SN.

[ test example 1 ]

The performance indexes of the mortar prepared by using the accelerating agents of examples 1-8 and comparative examples 1-4 are detected according to a method of national standard JC477-2005 accelerator special for sprayed concrete, and specific detection results are shown in Table 1. The preparation method of the mortar comprises the following steps of 900g of cement, 1350g of standard sand and 450g of water, wherein the type of the cement is P.042.5, and the mixing amount is 6%.

The test method of the stabilization period comprises the following steps: and (4) judging whether the accelerator is layered or not at the temperature of-15 ℃, and if so, ending the stabilization period.

TABLE 1

Comparing the examples with the comparative examples, it can be seen that the low alkali setting accelerator prepared by the method of the present invention has better low temperature stability, still has shorter setting hardening time and better strength at low temperature, compared to comparative example 1 (no use of sodium fluorosilicate), comparative example 2 (no use of stabilizer), comparative example 3 (no use of inorganic modifying material), and comparative example 4 (commercially available low alkali setting accelerator).

Comparing examples 1-3 with example 4 (aluminum sulfate was added in one portion at step 1), example 5 (aluminum sulfate was added in one portion at step 3), example 6 (aluminum sulfate was added in one portion at the last step), example 7 and example 8 (the amounts of the respective substances were not within the preferable range of the present invention), it can be seen that the low-alkali setting accelerator prepared by the preferable method of the present invention is more effective.

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.