Preparation process and application of super-sulfated cement anti-freezing agent

Abstract

The application relates to the technical field of super-sulfate cement, and particularly discloses a preparation process of a super-sulfate cement antifreeze and application thereof, which comprises the following steps: (1) adding mesoporous silicon dioxide powder into an amino-trimethylene phosphonic acid solution, and then performing heating and stirring reaction in a protective atmosphere; after the reaction is completed, a solid product is separated, washed and dried to obtain a pretreated powder; (2) adding the pretreated powder into a hexanediamine solution to perform heating and stirring reaction, separating a solid product, washing and drying the solid product to obtain modified mesoporous silicon dioxide powder; (3) adding sulfonic acid group modified carbon quantum dots into a suspension formed by the modified mesoporous silicon dioxide powder, and then performing heating, stirring and ultrasonic treatment; after the reaction is completed, a solid product is separated, washed and dried, and the super-sulfate cement antifreeze is obtained. The application utilizes the antifreeze to guide the directional generation of a hydration product C-S-H gel, forms a more compact C-S-H gel structure, and effectively solves the problem of insufficient frost resistance of the super-sulfate cement.

Description

Technical Field

[0001] This invention relates to the field of supersulfate cement technology, specifically to a preparation process and application of a supersulfate cement antifreeze agent. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Traditional concrete curing methods suffer from long curing cycles and low production efficiency. Steam-cured concrete has gained widespread application in the context of rapid urbanization. Supersulfated cement (SSC), using industrial byproducts as its main raw material, boasts advantages such as low carbon footprint, environmental friendliness, and high solid waste utilization. However, it suffers from drawbacks such as low early strength and susceptibility to carbonization. Furthermore, when steam curing temperatures exceed 65°C, the CSH gel, a hydration product in supersulfated cement, easily grows into a flocculent structure containing numerous micropores. This not only affects the mechanical strength of the supersulfated cement structure but also further deteriorates its frost resistance. Consequently, it is prone to freeze-thaw damage in harsh environments such as cold and high altitudes or in emergency engineering scenarios, severely impacting the safety and service life of engineering structures.

[0004] Freeze-thaw durability of concrete is one of the core challenges facing bridge engineering in cold regions, especially beam bridges and piers in long-term service. The nature of its failure is directly related to the internal pore structure of concrete: when concrete is subjected to freeze-thaw cycles, the free water inside expands in volume when it freezes at low temperatures, generating freeze-thaw stress within the concrete. During the thawing process, the concrete shrinks, causing shrinkage stress. This cycle of freeze-thaw and shrinkage stresses caused by periodic temperature changes is a crucial mechanism leading to fatigue damage and deterioration in concrete. It easily causes the initiation and propagation of microcracks within the concrete, ultimately leading to structural degradation problems such as surface spalling and strength loss. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a preparation process and application of a hypersulfate cement antifreeze agent. This invention utilizes the antifreeze agent to guide the directional formation of the hydration product CSH gel, effectively reducing internal porosity and ultimately forming a denser CSH gel structure, thus effectively solving the problem of insufficient freeze-thaw resistance in hypersulfate cement. Specifically, the technical solution of this invention is as follows.

[0006] In a first aspect, the present invention provides a preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0007] (1) Mesoporous silica powder was added to an aminotrimethylenephosphonic acid solution, and then the mixture was heated and stirred under a protective atmosphere. After the reaction was completed, the solid product was separated, washed, and dried to obtain a pretreated powder.

[0008] (2) The pretreated powder is added to the hexamethylenediamine solution and heated and stirred to react. After the reaction is completed, the solid product is separated, washed and dried to obtain modified mesoporous silica powder.

[0009] (3) A mixture of citric acid and sodium p-styrene sulfonate was subjected to a hydrothermal reaction. After the reaction was completed, the resulting reaction solution was purified to remove large carbon particles and unreacted insoluble impurities generated during the reaction. The purified liquid was then dialyzed, and the dialysate was freeze-dried to obtain sulfonic acid-modified carbon quantum dots.

[0010] (4) The sulfonic acid-modified carbon quantum dots are added to the suspension formed by the modified mesoporous silica powder, and then intermittent ultrasonic treatment is applied while heating and continuous stirring, so that the sulfonic acid-modified carbon quantum dots are loaded on the modified mesoporous silica powder particles and inside their pores. After completion, the solid product is separated, washed and dried to obtain the supersulfate cement antifreeze agent.

[0011] Further, in step (1), the ratio of the mesoporous silica powder to the aminotrimethylenephosphonic acid solution is 1~1.2g:50mL. Optionally, the molar concentration of the aminotrimethylenephosphonic acid solution is 0.8~1mol / L.

[0012] Further, in step (1), the heating and stirring reaction is carried out at a temperature of 60-80°C for 4-6 hours. During this process, the Si-OH on the surface of the mesoporous silica undergoes an ester exchange reaction with the HO-PO3H2 of aminotrimethylenephosphonic acid to form a Si-OP covalent bond, i.e., Si-OH+(HO)2P(O)-CH2-N[(CH2-PO3H2)2]→Si-OP(O)(OH)-CH2-N[(CH2-PO3H2)2]+H2O, thereby achieving the amination of the mesoporous silica.

[0013] Furthermore, in step (1), the drying temperature is 60~80℃ and the time is 8~12h.

[0014] Further, in step (2), the ratio of the pretreated powder to the hexamethylenediamine solution is 1~1.1g:40mL. Optionally, the molar concentration of the hexamethylenediamine solution is 0.2~0.3mol / L.

[0015] Further, in step (2), the heating and stirring reaction is carried out at a temperature of 90-100°C for 3-4 hours. During this process, the -PO3H2 on the pretreated powder undergoes an amidation reaction with the -NH2 of hexamethylenediamine to form a cross-linked network (-PO3H2+H2N-→-PO3HN-+H2O), thereby not only forming amino groups in a cross-linked network structure, but also increasing the amino group density on the surface of mesoporous silica.

[0016] Furthermore, in step (2), the drying temperature is 90~100℃ and the time is 8~12h.

[0017] Further, in step (3), the mass ratio of citric acid to sodium p-styrenesulfonate is 0.8~1.0g:1.0~1.5g.

[0018] Furthermore, in step (3), the temperature of the hydrothermal reaction is 180~200℃ and the time is 6~8h.

[0019] Further, in step (3), the molecular weight cutoff (MWCO) of the dialysis treatment is 500~1000 Da. Optionally, the dialysis treatment time is 24~48 h, during which the dialysis fluid is replaced every 4~6 h.

[0020] Further, in step (4), the modified mesoporous silica powder is added to water and ultrasonically treated to obtain the suspension. Optionally, the ratio of the modified mesoporous silica powder to water is 1g:50~100ml. The ultrasonic treatment time is 15~20min.

[0021] Further, in step (4), the mass ratio of the sulfonic acid-modified carbon quantum dots to the modified mesoporous silica powder is 0.05~0.1g:1g.

[0022] Further, in step (4), the heating temperature is 60~75℃. Optionally, the stirring rate is 300~400rpm.

[0023] Further, in step (4), the intermittent ultrasonic treatment includes applying ultrasonic treatment for 3 to 5 minutes every 25 to 30 minutes of stirring. Optionally, the continuous stirring time is 3 to 5 hours.

[0024] Furthermore, in step (4), the drying temperature is 45~60℃ and the time is 8~12h.

[0025] Secondly, the present invention provides the application of the antifreeze agent in hypersulfate cement. Optionally, the application is a frost-resistant hypersulfate cement comprising the following components in the following proportions: 10-15 parts by weight of anhydrite, 80-85 parts by weight of mineral powder, 3-5 parts by weight of cement, 1-2 parts by weight of calcium formate, 0.01-0.03 parts by weight of the hypersulfate cement antifreeze agent, and 37-52 parts by weight of mixing water.

[0026] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0027] This invention utilizes a finely designed nanostructured antifreeze agent to guide the directional growth of CSH gel, a hydration product of hypersulfate cement, during steam curing. This effectively reduces the formation of internal pores, ultimately resulting in a denser CSH gel structure and overcoming the problem of insufficient freeze-thaw resistance in hypersulfate cement. To this end, this invention first pretreats mesoporous silica with aminotrimethylenephosphonic acid, and then further amidates it with hexamethylenediamine, forming a high-density, cross-linked network of amino groups on the surface of the mesoporous silica particles. On one hand, these cross-linked network amino groups preferentially adsorb calcium ions (Ca ions) from the cement using the lone pair electrons on their nitrogen atoms. 2+ The amino groups serve as nucleation sites for CSH gel growth, inducing dense deposition of CSH gel on the surface of mesoporous silica particles, thus reducing the total porosity of the cement matrix. Simultaneously, the high-density amino groups in the mesoporous silica particles promote the uniform formation of hydration products, helping to suppress thermal stress cracking during steam curing and eliminate potential freeze-thaw resistance issues caused by steam curing. Furthermore, the high-density amino groups, through hydrogen bonds and coordination bonds with hydration products (CSH, AFt, etc.), significantly enhance the interfacial bonding strength between the mesoporous silica particles and the cement matrix, contributing to improved resistance to frost heave stress. Moreover, the flexibility provided by the cross-linked network structure of the amino groups buffers frost heave stress, thereby reducing interfacial debonding and microcrack formation. Finally, the amino groups on the surface of the mesoporous silica, through their coordination effect, not only effectively inhibit the dissolution and recrystallization of hydration products (AFt) during freeze-thaw cycles but also increase the cross-linking degree of the CSH gel, enhancing its resistance to freeze-thaw dehydration and preventing matrix cracking caused by the deterioration of hydration products.

[0028] Furthermore, this invention also loads sulfonic acid-modified carbon quantum dots onto the mesoporous silica microparticles. On one hand, these carbon quantum dots provide a directional growth template for the hydration product CSH gel. This is because CSH gel tends to grow randomly into a porous network structure under high-temperature steam curing conditions, but under the influence of the sulfonic acid-modified carbon quantum dots as an inducing agent, CSH gel tends to grow along the surface of the pores of the mesoporous nano-silica. This guiding effect not only accelerates the hydration reaction rate but also makes the resulting gel arrangement more dense and uniform, thereby improving the structural density of the supersulfate cement and enhancing its freeze-thaw resistance. On the other hand, the abundant sulfonic acid groups on the surface of the carbon quantum dots can form extremely strong hydrogen bonds with water molecules and form a dense "hydration layer" around the carbon quantum dots. This disrupts the orderly arrangement of surrounding free water molecules, hindering the migration and deposition of water molecules to the ice crystal surface, thereby inhibiting the growth of small ice crystals into destructive large ice crystals. This better prevents damage caused by frost heave stress and further enhances the freeze-thaw resistance of the supersulfate cement of this invention. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention and do not constitute an undue limitation of the invention.

[0030] Figure 1 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 1 below.

[0031] Figure 2 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 2 below.

[0032] Figure 3 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 3 below.

[0033] Figure 4 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 4 below.

[0034] Figure 5 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 5 below.

[0035] Figure 6 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 6 below.

[0036] Figure 7 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 7 below.

[0037] Figure 8 The image shows a sample of the supersulfate cement antifreeze agent prepared in Example 8 below. Detailed Implementation

[0038] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. The preferred embodiments and materials described in this invention are for illustrative purposes only. The technical solutions of the present invention will now be further described with reference to specific embodiments.

[0039] Example 1: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0040] (1) Mesoporous silica powder was added to a 1 mol / L aminotrimethylenephosphonic acid solution at a ratio of 1 g: 50 mL. The resulting solid-liquid mixture was then heated to 80 °C under nitrogen protection and magnetically stirred for 4 h. After the reaction was completed, the resulting reaction system was centrifuged (8000 r / min for 12 min). The lower solid product was then washed twice with deionized water and dried under vacuum at 70 °C for 10 h to obtain the pretreated powder.

[0041] (2) The pretreated powder was added to a hexamethylenediamine solution with a molar concentration of 0.3 mol / L, in a ratio of 1 g: 40 mL. The resulting solid-liquid mixture was then heated to 90 °C and refluxed for 3.5 h under stirring. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 15 min), and the resulting lower solid product was washed twice with deionized water and then heated to 100 °C and vacuum dried for 8 h to obtain modified mesoporous silica powder.

[0042] (3) Citric acid and sodium p-styrene sulfonate were added to water at a ratio of 0.85 g: 1.3 g and stirred until fully dissolved to obtain a mixture. The mixture was then transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, sealed, and heated to 200°C for hydrothermal reaction for 6 h. After completion, the mixture was cooled to room temperature, and the resulting reaction solution was filtered through a 0.22 μm microporous membrane. The resulting purified liquid was injected into a dialysis bag with a molecular weight cutoff of 500 Da, sealed, and suspended in the dialysate (deionized water). Dialysis was performed under magnetic stirring for 48 h, with the dialysate replaced every 6 h. After completion, the dialysate was freeze-dried to obtain sulfonic acid-modified carbon quantum dots.

[0043] (4) The modified mesoporous silica powder was added to deionized water (ratio of 1g: 100ml) and ultrasonically treated for 20min to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots were added to the suspension at a ratio of 0.07g: 1g of sulfonic acid-modified carbon quantum dots to modified mesoporous silica powder. The mixture was then heated to 65℃ and continuously stirred for 4.5h at a stirring rate of 350rpm. During this process, ultrasonic treatment was applied for 5min every 30min of stirring. After completion, the solid product was separated by filtration, washed 5 times with anhydrous ethanol, and then heated to 60℃ and vacuum dried for 8h to obtain the supersulfate cement antifreeze agent. Figure 1 As shown.

[0044] 2. A freeze-resistant supersulfate cement, comprising the following components in the indicated proportions: 12 parts by weight of anhydrite, 83 parts by weight of mineral powder, 3.5 parts by weight of 42.5 ordinary Portland cement, 1.5 parts by weight of calcium formate, 0.025 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 44 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0045] Performance Testing: The mass loss rate of the specimens made from the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested according to the "Standard for Test Methods of Long-Term Performance and Durability of Concrete" (GBT 50082-2024). This test was used to characterize the freeze-thaw resistance of the supersulfate cement; a smaller mass loss rate indicates better freeze-thaw resistance. The results showed that the initial mass of the specimen was 8073.4 g, and the mass after 50 freeze-thaw cycles was 7916.0 g, resulting in a mass loss rate of 1.95%.

[0046] Example 2: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0047] (1) Mesoporous silica powder was added to an aminotrimethylenephosphonic acid solution with a molar concentration of 0.8 mol / L, in a ratio of 1 g: 50 mL. The resulting solid-liquid mixture was then heated to 60 °C under nitrogen protection and magnetically stirred for 6 h. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 10 min), and the lower solid product was washed twice with deionized water and then heated to 60 °C and vacuum dried for 12 h to obtain the pretreated powder.

[0048] (2) The pretreated powder was added to a hexamethylenediamine solution with a molar concentration of 0.25 mol / L, in a ratio of 1.1 g: 40 mL. The resulting solid-liquid mixture was then heated to 100 °C and refluxed for 4 h under stirring. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 15 min), and the resulting lower solid product was washed twice with deionized water and then heated to 90 °C and vacuum dried for 12 h to obtain modified mesoporous silica powder.

[0049] (3) Citric acid and sodium p-styrene sulfonate were added to water at a ratio of 0.8 g: 1.0 g and stirred until fully dissolved to obtain a mixture. The mixture was then transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, sealed, and heated to 190°C for hydrothermal reaction for 7 h. After completion, the mixture was cooled to room temperature, and the resulting reaction solution was filtered through a 0.22 μm microporous membrane. The resulting purified liquid was then injected into a dialysis bag with a molecular weight cutoff of 1000 Da, sealed, and suspended in the dialysis fluid (deionized water). Dialysis was performed under magnetic stirring for 36 h, with the dialysis fluid replaced every 6 h. After completion, the dialysis solution was freeze-dried to obtain sulfonic acid-modified carbon quantum dots.

[0050] (4) The modified mesoporous silica powder was added to deionized water (ratio of 1g: 75ml) and ultrasonically treated for 20min to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots were added to the suspension at a ratio of 0.05g: 1g of sulfonic acid-modified carbon quantum dots to modified mesoporous silica powder. The mixture was then heated to 60℃ and continuously stirred for 5h at a stirring rate of 400rpm. During this process, ultrasonic treatment was applied for 3min every 30min of stirring. After completion, the solid product was separated by filtration, washed 9 times with anhydrous ethanol, and then heated to 45℃ and vacuum dried for 12h to obtain the supersulfate cement antifreeze agent. Figure 2 As shown.

[0051] 2. A freeze-resistant supersulfate cement, comprising the following components in the following proportions: 10 parts by weight of anhydrite, 80 parts by weight of mineral powder, 3 parts by weight of 42.5 ordinary Portland cement, 1 part by weight of calcium formate, 0.01 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 37 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0052] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8015.7g, and the mass after 50 freeze-thaw cycles was 7812.9g, resulting in a mass loss rate of 2.53%.

[0053] Example 3: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0054] (1) Mesoporous silica powder was added to a 1 mol / L aminotrimethylenephosphonic acid solution at a ratio of 1.2 g: 50 mL. The resulting solid-liquid mixture was then heated to 70 °C under nitrogen protection and magnetically stirred for 5.5 h. After completion, the reaction system was centrifuged (8000 r / min for 15 min), and the lower solid product was washed three times with deionized water and then heated to 80 °C and vacuum dried for 8 h to obtain the pretreated powder.

[0055] (2) The pretreated powder was added to a hexamethylenediamine solution with a molar concentration of 0.2 mol / L, in a ratio of 1 g: 40 mL. The resulting solid-liquid mixture was then heated to 100 °C and refluxed for 3 h under stirring. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 15 min), and the resulting lower solid product was washed twice with deionized water and then heated to 100 °C and vacuum dried for 8 h to obtain modified mesoporous silica powder.

[0056] (3) Citric acid and sodium p-styrene sulfonate were added to water at a ratio of 1.0 g: 1.5 g and stirred until fully dissolved to obtain a mixture. The mixture was then transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, sealed, and heated to 180°C for hydrothermal reaction for 8 h. After completion, the mixture was cooled to room temperature, and the resulting reaction solution was filtered through a 0.22 μm microporous membrane. The resulting purified liquid was then injected into a dialysis bag with a molecular weight cutoff of 1000 Da, sealed, and suspended in the dialysate (deionized water). Dialysis was performed under magnetic stirring for 24 h, with the dialysate being replaced every 4 h. After completion, the dialysate was freeze-dried to obtain sulfonic acid-modified carbon quantum dots.

[0057] (4) The modified mesoporous silica powder was added to deionized water (ratio of 1g: 50ml) and ultrasonically treated for 15min to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots were added to the suspension at a ratio of 0.1g: 1g to 0.1g of the modified mesoporous silica powder. The mixture was then heated to 75℃ and continuously stirred for 3h at a stirring rate of 300rpm. During this process, ultrasonic treatment was applied for 5min every 25min of stirring. After completion, the solid product was separated by filtration, washed 5 times with anhydrous ethanol, and then heated to 65℃ and vacuum dried for 10h to obtain the supersulfate cement antifreeze agent. Figure 3 As shown.

[0058] 2. A freeze-resistant supersulfate cement, comprising the following components in the following proportions: 15 parts by weight of anhydrite, 85 parts by weight of mineral powder, 5 parts by weight of 42.5 ordinary Portland cement, 2 parts by weight of calcium formate, 0.03 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 52 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0059] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8121.9g, and the mass after 50 freeze-thaw cycles was 7946.5g, resulting in a mass loss rate of 2.16%.

[0060] Example 4: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0061] Mesoporous silica powder was added to deionized water (ratio 1g: 100ml) and sonicated for 20 minutes to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots (same as in Example 1) were added to the suspension at a ratio of 0.07g: 1g of sulfonic acid-modified carbon quantum dots to mesoporous silica powder. The mixture was then heated to 65°C and continuously stirred at 350 rpm for 4.5 hours, with sonication applied for 5 minutes every 30 minutes of stirring. After completion, the solid product was separated by filtration, washed five times with anhydrous ethanol, and then heated to 60°C and vacuum dried for 8 hours to obtain the supersulfate cement antifreeze agent. Figure 4 As shown.

[0062] 2. A freeze-resistant supersulfate cement, comprising the following components in the indicated proportions: 12 parts by weight of anhydrite, 83 parts by weight of mineral powder, 3.5 parts by weight of 42.5 ordinary Portland cement, 1.5 parts by weight of calcium formate, 0.025 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 44 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0063] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8103.3g, and the mass after 50 freeze-thaw cycles was 7792.9g, resulting in a mass loss rate of 3.83%.

[0064] Example 5: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0065] (1) Mesoporous silica powder and anhydrous toluene were mixed at a ratio of 1 g: 100 mL to form a dispersion. Then, anhydrous toluene solution (containing 0.2 mol / L of 3-aminopropyltriethoxysilane) was added, and the ratio of mesoporous silica to 3-aminopropyltriethoxysilane was 1 g: 0.8 g. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 12 min). The lower solid product was then washed twice with anhydrous ethanol and heated to 70 °C and vacuum dried for 10 h to obtain the pretreated powder.

[0066] (2) The pretreated powder was added to a hexamethylenediamine solution with a molar concentration of 0.3 mol / L, in a ratio of 1 g: 40 mL. The resulting solid-liquid mixture was then heated to 90 °C and refluxed for 3.5 h under stirring. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 15 min), and the resulting lower solid product was washed twice with deionized water and then heated to 100 °C and vacuum dried for 8 h to obtain modified mesoporous silica powder.

[0067] (3) The modified mesoporous silica powder was added to deionized water (ratio of 1g: 100ml) and ultrasonically treated for 20min to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots (same as in Example 1 above) and modified mesoporous silica powder were added to the suspension at a ratio of 0.07g: 1g. The mixture was then heated to 65℃ and continuously stirred for 4.5h at a stirring rate of 350rpm. During this process, ultrasonic treatment was applied for 5min every 30min of stirring. After completion, the solid product was separated by filtration, washed 5 times with anhydrous ethanol, and then heated to 60℃ and vacuum dried for 8h to obtain the supersulfate cement antifreeze agent. Figure 5 As shown.

[0068] 2. A freeze-resistant supersulfate cement, comprising the following components in the indicated proportions: 12 parts by weight of anhydrite, 83 parts by weight of mineral powder, 3.5 parts by weight of 42.5 ordinary Portland cement, 1.5 parts by weight of calcium formate, 0.025 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 44 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0069] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8095.2g, and the mass after 50 freeze-thaw cycles was 7838.5g, resulting in a mass loss rate of 3.17%.

[0070] Example 6: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0071] (1) Mesoporous silica powder was added to an aminotrimethylenephosphonic acid solution with a molar concentration of 0.8 mol / L, in a ratio of 1 g: 50 mL. The resulting solid-liquid mixture was then heated to 60 °C under nitrogen protection and magnetically stirred for 6 h. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 10 min), and the lower solid product was washed twice with deionized water and then heated to 60 °C and vacuum dried for 12 h to obtain the pretreated powder.

[0072] (2) The pretreated powder was added to a hexamethylenediamine solution with a molar concentration of 0.25 mol / L, in a ratio of 1.1 g: 40 mL. The resulting solid-liquid mixture was then heated to 100 °C and refluxed for 4 h under stirring. After completion, the reaction system was centrifuged (8000 r / min for 15 min), and the lower solid product was washed twice with deionized water and then heated to 90 °C and vacuum dried for 12 h to obtain the supersulfate cement antifreeze agent, such as... Figure 6 As shown.

[0073] 2. A freeze-resistant supersulfate cement, comprising the following components in the following proportions: 10 parts by weight of anhydrite, 80 parts by weight of mineral powder, 3 parts by weight of 42.5 ordinary Portland cement, 1 part by weight of calcium formate, 0.01 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 37 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0074] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 7996.2g, and the mass after 50 freeze-thaw cycles was 7518.8g, resulting in a mass loss rate of 5.97%.

[0075] Example 7: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0076] Modified mesoporous silica powder (same as in Example 3 above) was added to deionized water (ratio of 1g:50ml) and sonicated for 15 minutes to obtain a suspension. Then, carbon quantum dots were added to the suspension at a ratio of 0.1g:1g to carbon quantum dots of modified mesoporous silica powder. The mixture was then heated to 75°C and continuously stirred at 300 rpm for 3 hours, with sonication applied for 5 minutes every 25 minutes of stirring. After completion, the solid product was separated by filtration, washed five times with anhydrous ethanol, and then heated to 65°C and vacuum dried for 10 hours to obtain the supersulfate cement antifreeze agent. Figure 7 As shown.

[0077] 2. A freeze-resistant supersulfate cement, comprising the following components in the following proportions: 15 parts by weight of anhydrite, 85 parts by weight of mineral powder, 5 parts by weight of 42.5 ordinary Portland cement, 2 parts by weight of calcium formate, 0.03 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 52 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0078] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8008.4g, and the mass after 50 freeze-thaw cycles was 7665.6g, resulting in a mass loss rate of 4.28%.

[0079] Example 8: 1. A preparation process for a supersulfate cement antifreeze agent, comprising the following steps:

[0080] (1) Mesoporous silica powder was added to an aminotrimethylenephosphonic acid solution with a molar concentration of 0.8 mol / L, in a ratio of 1 g: 50 mL. The resulting solid-liquid mixture was then heated to 60 °C under nitrogen protection and magnetically stirred for 6 h. After completion, the reaction system was centrifuged (at a rate of 8000 r / min for 10 min), and the lower solid product was washed twice with deionized water and then heated to 60 °C and vacuum dried for 12 h to obtain the pretreated powder.

[0081] (2) The pretreated powder was added to deionized water (ratio of 1g: 75ml) and ultrasonically treated for 20min to obtain a suspension. Then, sulfonic acid-modified carbon quantum dots (same as in Example 2 above) and the pretreated powder were added to the suspension at a ratio of 0.05g: 1g. The mixture was then heated to 60℃ and continuously stirred for 5h at a stirring rate of 400rpm. During this process, ultrasonic treatment was applied for 3min every 30min of stirring. After completion, the solid product was separated by filtration, washed 9 times with anhydrous ethanol, and then heated to 45℃ and vacuum dried for 12h to obtain the supersulfate cement antifreeze agent. Figure 8 As shown.

[0082] 2. A freeze-resistant supersulfate cement, comprising the following components in the following proportions: 10 parts by weight of anhydrite, 80 parts by weight of mineral powder, 3 parts by weight of 42.5 ordinary Portland cement, 1 part by weight of calcium formate, 0.01 parts by weight of the supersulfate cement antifreeze agent prepared in this embodiment, and 37 parts by weight of mixing water. The above components are mixed and stirred until homogeneous to obtain the supersulfate cement.

[0083] Performance testing: The mass loss rate of the specimens made of the supersulfate cement prepared in this embodiment after freeze-thaw cycles was tested using the same method as in Example 1 above. The results showed that the initial mass of the specimen was 8068.6g, and the mass after 50 freeze-thaw cycles was 7690.2g, resulting in a mass loss rate of 4.69%.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., should be included within the protection scope of the present invention.

Claims

1. A process for the preparation of a super-sulfated cement deicer, characterized in that, The method comprises the following steps: (1) adding mesoporous silica powder to an amino trimethylene phosphonic acid solution in a ratio of 1-1.2 g: 50 mL, and then performing a heating and stirring reaction in a protective atmosphere; after completion, separating out the solid product, washing and drying it to obtain a pretreated powder; the heating and stirring reaction is performed at a temperature of 60-80 ℃ for 4-6 h; (2) adding the pretreated powder to a hexanediamine solution in a ratio of 1-1.1 g: 40 mL to perform a heating and stirring reaction, and after completion, separating out the solid product, washing and drying it to obtain a modified mesoporous silica powder; the heating and stirring reaction is performed at a temperature of 90-100 ℃ for 3-4 h; (3) adding a mixture of citric acid and sodium p-styrenesulfonate in a ratio of 0.8-1.0 g: 1.0-1.5 g to perform a hydrothermal reaction, and after completion, removing impurities from the obtained reaction liquid; after completion, performing dialysis treatment on the obtained pure liquid, and then freeze-drying the dialysate to obtain sulfonic acid group modified carbon quantum dots; the hydrothermal reaction is performed at a temperature of 180-200 ℃ for 6-8 h; (4) adding the sulfonic acid group modified carbon quantum dots to a suspension liquid formed by the modified mesoporous silica powder in a ratio of 0.05-0.1 g: 1 g, and then applying intermittent ultrasonic treatment while heating and continuously stirring; after completion, separating out the solid product, washing and drying it to obtain the super-sulfate cement antifreeze.

2. The process for the preparation of a super-sulfated cement deicer according to claim 1, characterized in that, In step (1), the amino trimethylene phosphonic acid solution has a molar concentration of 0.8-1 mol / L; or, in step (1), the drying is performed at a temperature of 60-80 ℃ for 8-12 h.

3. The process for the preparation of super-sulfated cement deicer as claimed in claim 1 wherein, In step (2), the hexanediamine solution has a molar concentration of 0.2-0.3 mol / L; or, in step (2), the drying is performed at a temperature of 90-100 ℃ for 8-12 h.

4. The process for the preparation of super-sulfated cement deicer according to claim 1, characterized in that, In step (3), the dialysis treatment has a molecular weight cut-off of 500-1000 Da; or, in step (3), the dialysis treatment is performed for 24-48 h, and the dialysis external liquid is replaced every 4-6 h.

5. The process for the preparation of super-sulfated cement deicer as claimed in claim 1 wherein, In step (4), the modified mesoporous silica powder is added to water to perform ultrasonic treatment to obtain the suspension liquid.

6. The process for the preparation of a super-sulfated cement frost resistant agent according to claim 5, characterized in that, The ratio of the modified mesoporous silica powder to water is 1 g: 50-100 mL; or, the ultrasonic treatment is performed for 15-20 min.

7. The process for the preparation of super-sulfated cement deicer as claimed in claim 1 wherein, In step (4), the heating is performed at a temperature of 60-75 ℃; or, in step (4), the stirring is performed at a rate of 300-400 rpm.

8. The process for the preparation of a super-sulfated cement de-icing agent according to any one of claims 1-7, characterized in that, In step (4), the intermittent ultrasonic treatment comprises: applying ultrasonic treatment for 3-5 min every 25-30 min of stirring.

9. Process for the preparation of a super-sulfated cement deicer according to any one of claims 1-7, characterized in that, In step (4), the continuous stirring is performed for 3-5 h; or, in step (4), the drying is performed at a temperature of 45-60 ℃ for 8-12 h.

10. Use of the antifreezer prepared by the process of any one of claims 1 to 9 in super-sulfated cement, wherein the super-sulfated cement comprises components in the following proportions: 10 to 15 parts by weight of hard gypsum, 80 to 85 parts by weight of mineral powder, 3 to 5 parts by weight of cement, 1 to 2 parts by weight of calcium formate, 0.01 to 0.03 parts by weight of the super-sulfated cement antifreezer, and 37 to 52 parts by weight of mixing water.

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