Method for preparing light foaming cement by adopting split type micro equipment

Abstract

After a proper amount of the slow-release water reducing agent is added into the basic magnesium sulfate foamed cement material, the compressive strength of the foamed cement can be remarkably improved. Specifically, along with the increase of the dosage of the slow-release type water reducing agent, the compressive strength of the foaming cement is in a trend of firstly increasing and then reducing, and meanwhile, the drying density of the foaming cement is gradually increased. The foaming cement material pursues lighter texture, so that the use amount of the slow-release water reducing agent needs to be strictly controlled in actual use. On the other hand, split type micro equipment with a foaming machine and a stirring machine separated is adopted, and finer and more uniform foam can be obtained in the foaming process.

Description

Technical Field

[0001] The invention relates to the field of foamed cement, and in particular to a method for preparing lightweight foamed cement by using split-type micro-equipment. Background Art

[0002] Foamed cement composite panels are lightweight, durable, thermally insulating, soundproof, waterproof, and have minimal shrinkage. This combination of excellent properties allows for flexible application in various construction applications, significantly improving energy efficiency, fire resistance, and construction speed. Portland cement is generally the preferred cement material. However, compared to ordinary Portland cement, basic magnesium sulfate cement offers advantages such as higher strength (approximately 30%-50% higher than ordinary Portland general-purpose cement), faster hardening, and lower alkalinity. Therefore, it is necessary to design a basic magnesium sulfate foamed cement material with excellent performance. Summary of the Invention

[0003] The object of the present invention is to provide a method for preparing lightweight foamed cement using a split micro-device, so as to obtain a basic magnesium sulfate foamed cement material with excellent performance.

[0004] The technical solutions of the present invention are as follows: A method for preparing lightweight foamed cement using a split micro-device comprises the following steps: 500-550 g of MgSO4·7H2O was weighed and dissolved in 500-800 mL of water. The mixture was stirred in a water bath at 50-55° C. to fully dissolve the mixture. 13.2-13.5 g of citric acid was added and stirred at a speed of 300-320 r / min for 15-20 min. Then, 11-13 g of sodium dodecylbenzenesulfonate as a foaming agent was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455-460 g of α-MgO and 48-98 g of a slow-release water reducer were slowly added. The mixture was stirred at a high speed of 1500-1800 r / min to cause a hydration and gelling reaction to occur, thereby obtaining a basic magnesium sulfate foam slurry. The foamed slurry was poured into a mold of 50 mm×50 mm×50 mm, cured at 20-25° C. and a humidity of 55-58% for 20-24 h, and then demolded to obtain basic magnesium sulfate foamed cement.

[0005] Preferably, the mass of the MgSO4·7H2O is 500 g.

[0006] Preferably, the mass of the citric acid is 13.2 g.

[0007] Preferably, the mass of the foaming agent is 11 g.

[0008] Preferably, the humidity is 55%.

[0009] Preferably, the curing time is 24 hours.

[0010] Preferably, the curing temperature is 20°C.

[0011] Preferably, the stirring speed is 320 r / min.

[0012] The present invention can significantly improve the compressive strength of the foamed cement by adding an appropriate amount of a slow-release water-reducing agent to the basic magnesium sulfate foamed cement material. Specifically, as the amount of the slow-release water-reducing agent increases, the compressive strength of the foamed cement shows a trend of first increasing and then decreasing. At the same time, the dry density of the foamed cement gradually increases. Since the foamed cement material pursues a lighter texture, the amount of the slow-release water-reducing agent needs to be strictly controlled during actual use. On the other hand, the present invention uses a split micro-device with a foaming machine and a stirrer separated, which can obtain a more delicate and uniform foam during the foaming process. DETAILED DESCRIPTION

[0013] The technical effects of the present invention are verified below through specific examples, but the embodiments of the present invention are not limited thereto.

[0014] The preparation method of the sustained-release water reducer of the present invention comprises the following steps: weighing 100 parts by weight of methyl allyl polyoxyethylene ether HPEG-2400, fully dissolving the mixture at 32° C. under magnetic stirring, adding 1.5 parts by weight of hydrogen peroxide, and continuously dropwise adding a mixed solution of acrylic acid, hydroxyethyl acrylate, and acrylamide (the molar ratio of methyl allyl polyoxyethylene ether HPEG-2400, acrylic acid, hydroxyethyl acrylate, and acrylamide being 1:1.6:3.9:0.85) and an aqueous solution of 1.1 parts by weight of ascorbic acid and 0.55 parts by weight of mercaptopropionic acid. After the dropwise addition is completed over a period of about 3 hours, the mixture is kept warm for 2 hours, and NaOH is added to adjust the pH to 6.5 to obtain the sustained-release water reducer.

[0015] Example 1

[0016] 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 48 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry. The foaming slurry was poured into a 50 mm × 50 mm × 50 mm mold and cured at 20°C and a humidity of 55% for 24 h before demolding to obtain basic magnesium sulfate foamed cement.

[0017] Example 2

[0018] 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 60 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur, thereby obtaining a basic magnesium sulfate foam slurry. The foamed slurry was poured into a 50 mm × 50 mm × 50 mm mold, cured at 20°C and a humidity of 55% for 24 h, and then demolded to obtain basic magnesium sulfate foamed cement.

[0019] Example 3

[0020] 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 74 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry. The foaming slurry was poured into a 50 mm × 50 mm × 50 mm mold and cured at 20°C and a humidity of 55% for 24 h before demolding to obtain basic magnesium sulfate foamed cement.

[0021] Example 4

[0022] 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 87.2 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry. The foaming slurry was poured into a 50 mm × 50 mm × 50 mm mold and cured at 20°C and a humidity of 55% for 24 h before demolding to obtain basic magnesium sulfate foamed cement.

[0023] Example 5

[0024] 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 98 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry. The foaming slurry was poured into a 50 mm × 50 mm × 50 mm mold and cured at 20°C and a humidity of 55% for 24 h before demolding to obtain basic magnesium sulfate foamed cement.

[0025] Comparative Example 1 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water, stirred in a water bath at 50°C to fully dissolve it, 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min, and then 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine, and then 455 g of α-MgO was slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry, which was poured into a 50 mm × 50 mm × 50 mm mold, cured at 20°C and a humidity of 55% for 24 h, and then demolded to obtain basic magnesium sulfate foamed cement.

[0026] Comparative Example 2 500 g of MgSO4·7H2O was weighed and dissolved in 500 mL of water. The mixture was stirred in a water bath at 50°C to fully dissolve the mixture. 13.2 g of citric acid was added and stirred at a speed of 300 r / min for 15 min. Then, 11 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455 g of α-MgO and 150 g of a slow-release water reducer were slowly added and stirred at a high speed of 1500 r / min to cause a hydration and gelling reaction to occur to obtain basic magnesium sulfate foaming slurry. The foaming slurry was poured into a 50 mm × 50 mm × 50 mm mold and cured at 20°C and a humidity of 55% for 24 h before demolding to obtain basic magnesium sulfate foamed cement.

[0027] Next, we evaluated the 7d compressive strength and dry density of the samples in Examples 1-5 and Comparative Examples 1-2. The experimental results are shown in Table 1.

[0028] Table 1 Test data of each sample

[0029] As shown in Table 1, adding an appropriate amount of slow-release water reducer to basic magnesium sulfate foamed cement significantly improves the compressive strength of the foamed cement. Specifically, as the amount of slow-release water reducer increases, the compressive strength of the foamed cement initially increases and then decreases. Simultaneously, the dry density of the foamed cement gradually increases. Because foamed cement materials are designed to be lightweight, the amount of slow-release water reducer must be strictly controlled in actual use.

[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing lightweight foamed cement using a split micro-device, characterized in that: The method comprises the following steps: 500-550 g of MgSO4·7H2O was weighed and dissolved in 500-800 mL of water. The mixture was stirred in a water bath at 50-55° C. to fully dissolve the mixture. 13.2-13.5 g of citric acid was added and stirred at a speed of 300-320 r / min for 15-20 min. Then, 11-13 g of sodium dodecylbenzenesulfonate, a foaming agent, was added to obtain a magnesium sulfate solution containing a large amount of foam in a foaming machine. Then, 455-460 g of α-MgO and 48-98 g of a slow-release water reducer were slowly added. The mixture was stirred at a high speed of 1500-1800 r / min to cause a hydration and gelling reaction to occur, thereby obtaining a basic magnesium sulfate foam slurry. The foamed slurry was poured into a mold of 50 mm×50 mm×50 mm, cured at 20-25° C. and a humidity of 55-58% for 20-24 h, and then demolded to obtain basic magnesium sulfate foamed cement.

2. A method according to claim 1, characterized in that The mass of the MgSO4·7H2O is 500 g.

3. A method according to claim 1, characterized in that The mass of the citric acid is 13.2 g.

4. A method according to claim 1-2, characterized in that The mass of the foaming agent is 11 g.

5. A method according to claim 1, characterized in that The humidity was 55%.

6. A method according to claim 1, characterized in that The curing time is 24 hours.

7. A method according to claim 1, characterized in that The curing temperature is 20°C.

8. A method according to claim 1, characterized in that The stirring speed is 320 r / min.

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