Preparation method of fluorine-free alkali-free sulfur-free chlorine-free alkali-free liquid setting accelerator
The preparation of liquid quick-coagulant by a combination of fluorine-free, alkali-free, sulfur-free, and chlorine-free combinations has been solved, and the problems of reducing concrete durability and fluoride health hazards caused by sulfate ions in the liquid quick-coagulant are achieved, achieving high early strength and stability , meets the safety and performance specifications of sprayed concrete.
Patent Information
- Application Number
- CN202411499863.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-01-17
AI Technical Summary
The high content of sulfate ions in use of existing liquid alkali-free quick-coagulant agents leads to reduced durability of concrete, sulfate corrosion, low early strength, and the health hazards of fluoride to the environment and human body, and have great safety hazards.
Using fluorine-free, alkali-free, sulfur-free, and chlorine-free combination materials, including organoaluminum salts, organic coagulant, nano-silica and premature strength agents, liquid coagulant is prepared through stirring and filtration processes to ensure that it does not contain sulfate and fluorine. and alkali, pure organic materials and high purity water are used to improve the durability and safety of concrete.
It achieves high early strength, stability and corrosion resistance of alkali-free liquid accelerator, avoids sulfate corrosion and fluoride pollution inside concrete, meets the safety and performance requirements of sprayed concrete, and complies with the QC/R807-2020 specifications.
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Figure CN119320253A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of preparation of alkali-free liquid accelerating setting agent, in particular to a preparation method of fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid accelerating setting agent. Background Art
[0002] Accelerator is an admixture that can make concrete set and harden quickly. Its main use is to prepare shotcrete. It is an indispensable material in shotcrete construction.
[0003] my country's early liquid accelerator products were mainly high-alkali accelerators such as sodium aluminate or sodium silicate, which often contained a high alkali content, causing the later strength of concrete to decrease, the risk of alkali-aggregate reaction to be high, and posing a major safety hazard to spraying workers.
[0004] In recent years, with the advancement of underground support engineering construction, the development of liquid alkali-free accelerators has been relatively rapid, but the technology is still not mature enough, and there are many problems that need to be solved urgently as follows: Existing preparation technologies mostly use high-content sulfate materials such as aluminum sulfate and magnesium sulfate as the core accelerating components of alkali-free liquid accelerators. A higher amount of aluminum sulfate brings more sulfate ions into the concrete, which will cause or promote sulfate erosion inside the concrete and affect the durability of the concrete.
[0005] In recent years, there are many development ideas for using fluorine-containing acids or fluorine salts to improve the accelerating properties of liquid alkali-free accelerators. Since the solubility of aluminum sulfate is not large enough, some patents use hydrofluoric acid, fluorosilicic acid or other fluorine-containing acids to react with aluminum hydroxide to enhance the aluminum phase concentration in alkali-free accelerators. However, when the proportion of fluorine-containing acids or fluorine salts is high, it is easy to cause a low pH value of the accelerator system and low early strength of concrete. Secondly, it brings corrosion risks in production and use. Fluoride contact with the human body or ingestion can easily cause health hazards such as fluorosis. Summary of the invention
[0006] In view of the deficiencies in the prior art, the present invention provides a method for preparing an alkali-free liquid accelerating setting agent. The prepared accelerating setting agent contains no sulfate radical, no fluorine, no alkali, and no chloride ion.
[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid quick-setting agent, characterized in that it comprises the following components; Organic aluminum salt: 200-400 parts, organic coagulant: 30-120 parts, nano silicon dioxide: 5-20 parts, early strength agent: 0.5-30 parts, water: 130-740 parts.
[0008] The preparation method of the fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid accelerating setting agent comprises the following steps: Step 1: uniformly mix the water organic aluminum salt, the organic coagulant, the fumed nano-silica and the early strength agent according to a certain proportion, stir at a speed of not less than 130 rpm, and stir for 2-3 hours to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid quick-setting agent.
[0009] Step 2: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to ensure the purity and quality of the final product.
[0010] Preferably, the organic aluminum salt is one or a combination of aluminum formate, aluminum acetate, and aluminum oxalate; Preferably, the organic coagulant is prepared by the following method: S1. Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0011] S2. Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0012] S3. Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0013] S4, finally slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Preferably, in the organic coagulant, the content of triethanolamine is ≥99%; the content of formaldehyde is 50% industrial formaldehyde; and the content of formic acid is ≥99%.
[0014] Preferably, the organic early strength agent is one of lithium carbonate and lithium oxalate, or a combination of both.
[0015] Preferably, the nano-silicon dioxide has a particle size of less than 15 nanometers and a purity of greater than 99.9%.
[0016] The present invention provides a method for preparing a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent. It has the following beneficial effects: 1. The quick-setting agent of the present invention does not contain alkali metals such as sodium and potassium, thereby avoiding the alkali-aggregate reaction of shotcrete performance, improving the durability of concrete, and avoiding potential safety hazards in the production and construction process.
[0017] 2. The present invention uses pure organic accelerating components and does not contain sulfate radicals, thereby avoiding sulfate corrosion inside the concrete and improving the durability and corrosion resistance of the concrete.
[0018] 3. The present invention uses organic materials and does not contain fluorine, thereby avoiding the pollution of fluoride to the environment and the potential safety hazards during production and use.
[0019] 4. The accelerator of the present invention has the characteristics of fast setting time, high early strength and good stability by using organic materials. At 7% dosage, the setting time is less than 5min, the final setting time is less than 6min, the 6-hour mortar strength is greater than 1.5MPa, the 1-day mortar strength is greater than 16MPa, and the 28-day compressive strength ratio is greater than 95%, which fully meets the requirements of QC / R807-2020 "Liquid Alkali-free Accelerator for Tunnel Shotcrete". BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a stereogram of the present invention. DETAILED DESCRIPTION
[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0022] Embodiment 1: The embodiment of the present invention provides a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent, comprising the following components; Aluminum formate: 400 parts, organic coagulant: 240 parts, nano silicon dioxide: 20 parts, lithium formate: 20 parts, water: 320 parts.
[0023] The preparation method of the fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid accelerating setting agent comprises the following steps: Step 1: Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0024] Step 2: Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0025] Step 3: Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0026] Step 4: Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Step 5: Add 240 parts of the organic coagulant prepared above and 320 parts of water into the reactor, start stirring at a speed of not less than 130 rpm, then add 400 parts of aluminum formate, 20 parts of nano-silicon dioxide and 20 parts of an early strength agent into the reactor in sequence and stir for 2-3 hours.
[0027] Step 6: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent.
[0028] In one embodiment, the water used is specially treated ultrapure water, which is prepared through multi-stage treatment steps of reverse osmosis, ion exchange and ultraviolet sterilization. The water purity reaches above 18.2 MΩ·cm, which can effectively remove organic matter, inorganic salts and microorganisms that may exist in the water.
[0029] In one embodiment, the preparation process of ultrapure water is: Reverse Osmosis (RO): Reverse osmosis technology removes most of the dissolved organic matter, inorganic salts and microorganisms in water through a semi-permeable membrane under pressure. The reverse osmosis membrane has extremely high selectivity and can block most impurities, making the output water close to pure.
[0030] Ion Exchange (IX): The water treated by reverse osmosis is further passed through ion exchange resins to remove residual ionic impurities. Cation exchange resins and anion exchange resins remove cations and anions from the water, respectively, further purifying the water.
[0031] Ultraviolet sterilization (UV): Finally, the water is sterilized by ultraviolet light, which can effectively destroy the DNA and RNA of residual microorganisms in the water, achieving a sterilization effect and ensuring that the water does not contain any microbial contamination.
[0032] Furthermore, the use of ultrapure water as a solvent can ensure high efficiency and high purity in the dissolution process, avoiding the interference of impurities in the dissolution process; high-purity ultrapure water shows excellent stability and reliability in chemical reactions and experiments, ensuring the accuracy and repeatability of experimental results; effectively removing organic matter, inorganic salts and microorganisms, making the water pure and free of impurities, avoiding the interference of impurities in the dissolution process and chemical reactions.
[0033] Embodiment 2: Group distribution ratio: Aluminum acetate: 400 parts, organic coagulant: 240 parts, nano silicon dioxide: 20 parts, lithium formate: 20 parts, water: 320 parts.
[0034] Preparation steps: Step 1: Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0035] Step 2: Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0036] Step 3: Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0037] Step 4: Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Step 5: Add 240 parts of the organic coagulant prepared above and 320 parts of water into the reactor, start stirring, and the stirring speed is not less than 130 rpm. Then, add 400 parts of aluminum acetate, 20 parts of nano-silicon dioxide, and 20 parts of early strength agent into the reactor in sequence, and stir for 2-3 hours.
[0038] Step 6: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent.
[0039] Embodiment 3: Group distribution ratio: Aluminum oxalate: 400 parts, organic coagulant: 240 parts, nano silicon dioxide: 20 parts, lithium formate: 20 parts, water: 320 parts.
[0040] Preparation steps: Step 1: Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0041] Step 2: Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0042] Step 3: Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0043] Step 4: Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Step 5: Add 240 parts of the organic coagulant prepared above and 320 parts of water into the reactor, start stirring at a speed of not less than 130 rpm, then add 400 parts of aluminum oxalate, 20 parts of nano-silicon dioxide and 20 parts of an early strength agent into the reactor in sequence, and stir for 2-3 hours.
[0044] Step 6: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent.
[0045] Embodiment 4: Group distribution ratio: Aluminum formate: 200 parts, aluminum acetate: 100 parts, aluminum oxalate: 100 parts, organic coagulant: 240 parts, nano silicon dioxide: 20 parts, lithium oxalate: 20 parts, water: 320 parts.
[0046] Preparation steps: Step 1: Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0047] Step 2: Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0048] Step 3: Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0049] Step 4: Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Step 5: Add 240 parts of the organic coagulant prepared above and 320 parts of water into the reactor, start stirring, and the stirring speed is not less than 130 rpm. Then, add 400 parts of aluminum oxalate, 20 parts of nano-silicon dioxide, and 20 parts of early strength agent into the reactor in sequence, and stir for 2-3 hours.
[0050] Step 6: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent.
[0051] Embodiment 5: The embodiment of the present invention provides a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent, comprising the following components; Aluminum formate: 400 parts, organic coagulant: 180 parts, nano silicon dioxide: 20 parts, lithium formate: 20 parts, water: 320 parts.
[0052] The preparation method of the fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid accelerating setting agent comprises the following steps: Step 1: Mix 100 parts of triethanolamine and 60 parts of formaldehyde, stir and react for 30 minutes.
[0053] Step 2: Add 90 parts of formic acid, heat to 90°C, and continue stirring to react for 2 hours.
[0054] Step 3: Add 15 parts of aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours.
[0055] Step 4: Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant; Step 5: Add 180 parts of the organic coagulant prepared above and 320 parts of water into the reactor, start stirring at a speed of not less than 130 rpm, then add 400 parts of aluminum formate, 20 parts of nano-silicon dioxide and 20 parts of an early strength agent into the reactor in sequence and stir for 2-3 hours.
[0056] Step 6: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent.
[0057]
[0058] Table 1 Example 1 has the best comprehensive performance, with the highest setting time and compressive strength. It not only has superior performance in setting time and compressive strength, but also ensures higher stability.
Claims
1. A fluorine-free, alkali-free, sulfur-free, chlorine-free, alkali-free liquid quick-setting agent, characterized in that: It includes the following components; Organic aluminum salt: 200-400 parts, organic coagulant: 30-120 parts, nano silicon dioxide: 5-20 parts, early strength agent: 0.5-30 parts, water: 130-740 parts.
2. The method for preparing a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent according to claim 1, characterized in that The organic aluminum salt is one or a combination of aluminum formate, aluminum acetate, and aluminum oxalate.
3. A fluorine-free, alkali-free, sulfur-free, chlorine-free, alkali-free liquid quick-setting agent according to claim 1, characterized in that: Organic coagulants contain the following components: 100 parts of triethanolamine, 60 parts of formaldehyde, 90 parts of formic acid, 15 parts of aluminum hydroxide, and 30 parts of calcium hydroxide.
4. A fluorine-free, alkali-free, sulfur-free, chlorine-free, alkali-free liquid quick-setting agent according to claim 1, characterized in that The preparation of the organic coagulant comprises the following steps: S1, mixing triethanolamine and formaldehyde, stirring and reacting for 30 minutes; S2, add formic acid, heat to 90°C, and continue stirring to react for 2 hours; S3, add aluminum hydroxide, maintain the temperature at 90°C, and continue the reaction for 1-2 hours; S4. Finally, slowly add 30 parts of calcium hydroxide and stir for 30 minutes to obtain the organic coagulant.
5. The method for preparing a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent according to claim 1, characterized in that: The organic early strength agent is one of calcium formate, lithium carbonate and lithium oxalate or a combination of several thereof.
6. The method for preparing a fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent according to claim 1, characterized in that: The following steps are involved: Step 1, mixing water organic aluminum salt, organic coagulant, fumed nano-silica and early strength agent in proportion, stirring at a speed of not less than 130 rpm, and stirring for 2-3 hours to obtain the fluorine-free, alkali-free, sulfur-free, chlorine-free and alkali-free liquid accelerating setting agent; Step 2: Use a filter with a filtration accuracy of 400 meshes to remove unreacted particles and impurities from the fluorine-free, alkali-free, sulfur-free, chlorine-free, and alkali-free liquid accelerating setting agent after the above reaction is completed, so as to ensure the purity and quality of the final product.