Method for producing composite water reducing agent capable of realizing resource utilization

Abstract

The invention discloses a method for producing a composite water reducing agent capable of realizing resource utilization, which specifically comprises the following steps: mixing isopentenol polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate and water to obtain a mixed solution A, mixing acrylamide, dimethyl diallyl ammonium chloride, sodium methallyl sulfonate and water to obtain a mixed solution B, and mixing the mixed solution B with water to obtain the composite water reducing agent. The mixed solution A and the mixed solution B are mixed and heated, an initiator and a chain transfer agent are added for a reaction, and a modified water reducer solution is prepared; porous graphene is added into the modified water reducing agent solution, ball milling and filtering are conducted, sediment is washed with deionized water and then dried, the composite water reducing agent is prepared, and waste liquid generated in the process is reused for producing the modified water reducing agent solution. The prepared composite water reducing agent is good in water reducing effect, the mechanical property of a cement-based material can be effectively improved, waste liquid generated in production is recycled and reused, the preparation cost of the water reducing agent is reduced, and the situation that the environment is polluted by discharged waste liquid is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a method for producing a composite water reducing agent capable of realizing resource utilization. Background Art

[0002] Water reducer in cement, also known as high-efficiency water reducer and concrete water reducer, is a chemical additive used to improve the fluidity of concrete and reduce the water-cement ratio. Water reducer is widely used in concrete engineering, building materials and related industries, and can significantly improve the processing performance and quality of concrete.

[0003] Water reducers are usually composed of organic polymer compounds and have the characteristics of surfactants. They can interact with water molecules in concrete and change the surface tension of water molecules, thereby reducing the cohesion and adhesion between water and cement particles and improving the fluidity of concrete. Water reducers can be divided into three types: water lattice agents, retarders and high-efficiency water reducers. Water lattice agents enhance the fluidity of water by changing the structure of water; retarders can prolong the setting time of concrete and increase the strength of the aggregate; and high-efficiency water reducers are the most commonly used type of water reducers, which can significantly reduce the water-cement ratio of concrete, improve fluidity and increase compressive strength.

[0004] Polycarboxylic acid water reducer is a common high-efficiency water reducer, which can significantly reduce the water-cement ratio of concrete, improve fluidity, and make concrete have good processing properties. Compared with other water reducers, the water-reducing effect of polycarboxylic acid water reducer is more obvious, and polycarboxylic acid water reducer can improve the fluidity and uniformity of concrete, reduce pores and defects in concrete, and improve the compressive strength and durability of concrete. Polycarboxylic acid water reducer has good stability in concrete and will not cause segregation or dispersion problems. It can keep the fluidity and working performance of concrete stable for a long time. Due to the above advantages of polycarboxylic acid water reducer, it has been widely used. However, polycarboxylic acid water reducer also has the following problems: 1. Compared with other water reducers, the price of polycarboxylic acid water reducer is higher, which will increase the cost of concrete production. 2. The clay material in the matrix material has a certain adsorption effect on the polycarboxylic acid water reducer, which will reduce the effect of the water reducer. Therefore, in practical applications, it is necessary to modify the polycarboxylic acid water reducer.

[0005] In addition, a large amount of waste liquid will be generated during the preparation of polycarboxylic acid series. Direct discharge of the waste liquid will not only pollute the environment, but also cause waste of resources. How to recycle the waste liquid for resource utilization has become another problem that needs to be solved urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in view of the shortcomings of the prior art, a method for producing a composite water-reducing agent that can realize resource utilization is provided. The composite water-reducing agent prepared by the method not only has a good water-reducing effect, but also can effectively improve the mechanical properties of cement-based materials. Moreover, the present invention also recycles and reuses the waste liquid generated in the production, which not only reduces the preparation cost of the water-reducing agent, but also prevents the discharge of waste liquid from polluting the environment.

[0007] In order to solve the above technical problems, the technical solution of the present invention is:

[0008] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0009] (1) mixing isopentanol polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate and water to prepare a mixed solution A, mixing acrylamide, dimethyl diallyl ammonium chloride, sodium methacrylate sulfonate and water to prepare a mixed solution B, mixing the mixed solution A and the mixed solution B, raising the temperature, adding an initiator and a chain transfer agent, stirring and reacting, and preparing a modified water-reducing agent solution;

[0010] (2) adding porous graphene to the modified water-reducing agent solution, ball milling, filtering the ball milling liquid, washing the precipitate with deionized water until neutral, and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated in the washing process with the filtrate during the grinding liquid filtration, removing the solvent, and reused in the production of the modified water-reducing agent solution.

[0011] As a preferred embodiment of the above technical solution, in step (1), in the mixed solution A, the mass ratio of isopentanol polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate and water is 20-30:3-5:3-5:20-40.

[0012] As a preferred embodiment of the above technical solution, in step (1), in the mixed solution B, the mass ratio of acrylamide, dimethyldiallylammonium chloride, sodium methyl propylene sulfonate and water is 5-8:3-5:3-5:10-15.

[0013] As a preferred embodiment of the above technical solution, in step (1), the initiator is ammonium persulfate, the chain transfer agent is mercaptopropionic acid, the volume ratio of the mixed solution A to the mixed solution B is 2:(0.5-1), and the added amounts of the initiator and the chain transfer agent are 0.5-0.8% and 2-3% of the mass of the mixed solution, respectively.

[0014] As a preferred embodiment of the above technical solution, in step (1), the stirring reaction temperature is 50-55°C and the time is 30-60 minutes.

[0015] As a preferred embodiment of the above technical solution, in step (2), the porous graphene has a sheet size of 0.5-5 μm, a thickness of 3-4 nm, a pore size of 4-5 nm, and a specific surface area of ​​890-900 m 2 / g.

[0016] As a preferred embodiment of the above technical solution, in step (2), the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:(1-2).

[0017] As a preferred embodiment of the above technical solution, in step (2), the ball milling treatment time is 10-20 hours.

[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] The invention uses isopentanol polyoxyethylene ether as a macromolecular monomer, uses hydroxyethyl acrylate, acrylic acid and acrylamide as small molecular functional monomers, and uses dimethyldiallylammonium chloride and sodium methacrylate sulfonate as clay stabilizing components. The prepared water reducer has good stability and dispersibility and has certain anti-mud performance.

[0020] The present invention also adds porous graphene: the surface area of ​​porous graphene increases, and it has excellent water absorption performance and permeability, and can effectively absorb mud, impurities and other substances, which can reduce the problems of mud residue, silt and sand generated by the interaction between the water reducer and the mud, reduce the influence of the water reducer on the fluidity of the slurry during use, and improve the stability of the water reducer. In addition, porous graphene has excellent mechanical properties, such as high strength, high toughness, etc. Introducing porous graphene in the composite water reducer can enhance the mechanical strength and durability of the water reducer, making it difficult to break and fail during the construction process. This can improve the service life of the water reducer, improve the economy and construction effect of the water reducer. In addition, porous graphene also has a large specific surface area and pore structure, can provide a large adsorption surface, increase the contact area between the water reducer and the cement particles, and promote the reaction and compatibility of the water reducer and cement. This can improve the dispersibility and water retention of the water reducer, enhance the stability of the cement paste, and improve the fluidity and processability during the construction process.

[0021] The present invention also removes the solvent from the wastewater generated in the preparation of the composite water reducing agent and reuses it in the preparation of the water reducing agent, thereby greatly reducing the preparation cost of the water reducing agent, realizing resource recycling and reducing pollution to the environment. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0023] The raw materials in the following examples are not commercially available unless otherwise specified. The reaction conditions in the following examples are conventional conditions in the prior art unless otherwise specified.

[0024] The weight average molecular weight of the prenol polyoxyethylene ether in the following examples is 2,000.

[0025] Example 1

[0026] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0027] (1) In parts by weight, 20 parts of isopentanol polyoxyethylene ether, 3 parts of acrylic acid, 3 parts of hydroxyethyl acrylate and 20 parts of water are mixed to prepare a mixed solution A, 5 parts of acrylamide, 3 parts of dimethyldiallylammonium chloride, 3 parts of sodium methacrylate sulfonate and 10 parts of water are mixed to prepare a mixed solution B, the mixed solution A and the mixed solution B are mixed in a volume ratio of 2:1, the temperature is raised to 40°C, ammonium persulfate and mercaptopropionic acid are added (the amount of ammonium persulfate and mercaptopropionic acid added is 0.5% and 2% of the mass of the mixed solution, respectively), and the reaction is stirred at 50°C for 1 hour to prepare a modified water reducer solution;

[0028] (2) adding porous graphene to the modified water-reducing agent solution (the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:2), ball milling at 580 rpm for 10 h, filtering the ball milling solution, washing the precipitate with deionized water until it is neutral and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated during the washing process with the filtrate during the grinding liquid filtration, removing the solvent and reused in the production of the modified water-reducing agent solution.

[0029] Example 2

[0030] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0031] (1) In parts by weight, 22 parts of isopentanol polyoxyethylene ether, 3.5 parts of acrylic acid, 3.5 parts of hydroxyethyl acrylate and 25 parts of water are mixed to prepare a mixed solution A, 6 parts of acrylamide, 3.5 parts of dimethyldiallylammonium chloride, 3.5 parts of sodium methacrylate sulfonate and 12 parts of water are mixed to prepare a mixed solution B, the mixed solution A and the mixed solution B are mixed in a volume ratio of 2:1, the temperature is raised to 40°C, ammonium persulfate and mercaptopropionic acid are added (the amount of ammonium persulfate and mercaptopropionic acid added is 0.6% and 2% of the mass of the mixed solution, respectively), and the reaction is stirred at 50°C for 1 hour to prepare a modified water reducer solution;

[0032] (2) adding porous graphene to the modified water-reducing agent solution (the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:2), ball milling at 580 rpm for 15 h, filtering the ball milling solution, washing the precipitate with deionized water until it is neutral and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated during the washing process with the filtrate during the grinding liquid filtration, removing the solvent and reused in the production of the modified water-reducing agent solution.

[0033] Example 3

[0034] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0035] (1) In parts by weight, 25 parts of isopentanol polyoxyethylene ether, 4 parts of acrylic acid, 3 parts of hydroxyethyl acrylate and 30 parts of water are mixed to prepare a mixed solution A, 7 parts of acrylamide, 4 parts of dimethyldiallylammonium chloride, 3 parts of sodium methacrylate sulfonate and 10 parts of water are mixed to prepare a mixed solution B, the mixed solution A and the mixed solution B are mixed in a volume ratio of 2:1, the temperature is raised to 40°C, ammonium persulfate and mercaptopropionic acid are added (the amount of ammonium persulfate and mercaptopropionic acid added is 0.7% and 3% of the mass of the mixed solution, respectively), and the reaction is stirred at 50°C for 1 hour to prepare a modified water reducer solution;

[0036] (2) adding porous graphene to the modified water-reducing agent solution (the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:2), ball milling at 580 rpm for 15 h, filtering the ball milling solution, washing the precipitate with deionized water until it is neutral and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated during the washing process with the filtrate during the grinding liquid filtration, removing the solvent and reused in the production of the modified water-reducing agent solution.

[0037] Example 4

[0038] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0039] (1) In parts by weight, 25 parts of isopentanol polyoxyethylene ether, 5 parts of acrylic acid, 4 parts of hydroxyethyl acrylate and 30 parts of water are mixed to prepare a mixed solution A, 8 parts of acrylamide, 5 parts of dimethyldiallylammonium chloride, 4 parts of sodium methacrylate sulfonate and 15 parts of water are mixed to prepare a mixed solution B, the mixed solution A and the mixed solution B are mixed in a volume ratio of 2:1, the temperature is raised to 40°C, ammonium persulfate and mercaptopropionic acid are added (the amount of ammonium persulfate and mercaptopropionic acid added is 0.5% and 3% of the mass of the mixed solution, respectively), and the reaction is stirred at 50°C for 1 hour to prepare a modified water reducer solution;

[0040] (2) adding porous graphene to the modified water-reducing agent solution (the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:2), ball milling at 580 rpm for 15 h, filtering the ball milling solution, washing the precipitate with deionized water until it is neutral and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated during the washing process with the filtrate during the grinding liquid filtration, removing the solvent and reused in the production of the modified water-reducing agent solution.

[0041] Example 5

[0042] A method for producing a composite water reducing agent capable of realizing resource utilization comprises the following steps:

[0043] (1) In parts by weight, 30 parts of isopentanol polyoxyethylene ether, 5 parts of acrylic acid, 5 parts of hydroxyethyl acrylate and 40 parts of water are mixed to prepare a mixed solution A, 7 parts of acrylamide, 4 parts of dimethyldiallylammonium chloride, 5 parts of sodium methacrylate sulfonate and 15 parts of water are mixed to prepare a mixed solution B, the mixed solution A and the mixed solution B are mixed in a volume ratio of 2:1, the temperature is raised to 40°C, ammonium persulfate and mercaptopropionic acid are added (the amount of ammonium persulfate and mercaptopropionic acid added is 0.8% and 3% of the mass of the mixed solution, respectively), and the reaction is stirred at 50°C for 1 hour to prepare a modified water reducer solution;

[0044] (2) adding porous graphene to the modified water-reducing agent solution (the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:2), ball milling at 580 rpm for 20 h, filtering the ball milling solution, washing the precipitate with deionized water until it is neutral and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated during the washing process with the filtrate during the grinding liquid filtration, removing the solvent and reused in the production of the modified water-reducing agent solution.

[0045] In order to further illustrate the excellent performance of the water reducing agent provided by the present invention, the following comparative examples are given.

[0046] Comparative Example 1

[0047] The amount of prenol polyoxyethylene ether used is 40 parts, and other conditions are the same as those in Example 5.

[0048] Comparative Example 2

[0049] The amount of acrylamide used was 15 parts, and other conditions were the same as in Example 5.

[0050] Comparative Example 3

[0051] The dosage of sodium methacrylate sulfonate is 10 parts, and other conditions are the same as those in Example 5.

[0052] Comparative Example 4

[0053] The amount of dimethyldiallylammonium chloride used was 10 parts, and the other conditions were the same as those in Example 5.

[0054] Comparative Example 5

[0055] No porous graphene was added, and other conditions were the same as those in Example 5.

[0056] Comparative Example 6

[0057] The mass ratio of the modified water-reducing agent solution to the porous graphene is 3:2, and the other conditions are the same as those in Example 5.

[0058] The performance of the water reducing agents prepared in the above embodiments and comparative examples was tested below, and the test methods and test results are as follows.

[0059] The test was conducted in accordance with JC / T985-2005 "cement-based self-leveling mortar for floor", and the specific test sample was a mortar composed of 200 parts of water, 280 parts of cement, 80 parts of silica fume, 500 parts of 200 mesh quartz sand, 8 parts of bentonite, 3 parts of hydroxymethyl cellulose ether, and 1 part of water reducing agent, wherein the cement was P.O42.5R ordinary Portland cement. The test results are shown in Table 1.

[0060] Table 1

[0061]

[0062]

[0063] It can be seen from the above test results that, compared with the comparative example, the composite water reducer prepared in the present invention can effectively improve the fluidity, slump and mechanical properties of the material when used in cement-based materials.

[0064] In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for producing a composite water reducing agent that can realize resource utilization, characterized in that: The following steps are involved: (1) mixing isopentanol polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate and water to prepare a mixed solution A, mixing acrylamide, dimethyl diallyl ammonium chloride, sodium methacrylate sulfonate and water to prepare a mixed solution B, mixing the mixed solution A and the mixed solution B, raising the temperature, adding an initiator and a chain transfer agent, stirring and reacting, and preparing a modified water-reducing agent solution; (2) adding porous graphene to the modified water-reducing agent solution, ball milling, filtering the ball milling liquid, washing the precipitate with deionized water until neutral, and then drying to obtain a composite water-reducing agent, and mixing the wastewater generated in the washing process with the filtrate during the grinding liquid filtration, removing the solvent, and reused in the production of the modified water-reducing agent solution.

2. A method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (1), in the mixed solution A, the mass ratio of prenol polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate and water is 20-30:3-5:3-5:20-40.

3. A method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (1), in the mixed solution B, the mass ratio of acrylamide, dimethyldiallylammonium chloride, sodium methyl propylene sulfonate and water is 5-8:3-5:3-5:10-15.

4. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (1), the initiator is ammonium persulfate, and the chain transfer agent is mercaptopropionic acid.

5. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: The volume ratio of the mixed liquid A to the mixed liquid B is 2:(0.5-1), and the added amounts of the initiator and the chain transfer agent are 0.5-0.8% and 2-3% of the mass of the mixed liquid respectively.

6. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (1), the stirring reaction is carried out at a temperature of 50-55° C. and for a time of 30-60 min.

7. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (2), the porous graphene has a sheet size of 0.5-5 μm, a thickness of 3-4 nm, a pore size of 4-5 nm, and a specific surface area of ​​890-900 m 2 / g.

8. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (2), the mass ratio of the modified water-reducing agent solution to the porous graphene is 1:(1-2).

9. The method for producing a composite water reducing agent capable of realizing resource utilization according to claim 1, characterized in that: In step (2), the ball milling treatment time is 10-20 hours.

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