A concrete water reducing agent and a preparation method thereof

Abstract

The present application relates to the technical field of concrete water reducing agent, in particular to a kind of concrete water reducing agent and preparation method thereof.It includes the following steps: β-naphthalenesulfonate formaldehyde condensate solution and aliphatic hydroxyl sulfonate formaldehyde condensate solution are stirred to form main chain base fluid;Polyethylene glycol is dissolved in warm water, then dispersing agent is added, and stirring is carried out until completely dissolved to obtain additive solution;Then sodium carbonate and antioxidant are dissolved in additive solution, and then additive solution is slowly added into main chain base fluid;Defoaming agent is added into main chain base fluid and stirred to obtain mother liquor;The mother liquor is subjected to vacuum distillation treatment to remove excess moisture, and the solid content of the mother liquor is adjusted to obtain a concrete water reducing agent.In the present application, through the strong electrostatic repulsion of β-naphthalenesulfonate formaldehyde condensate, the flexible adsorption of aliphatic hydroxyl sulfonate formaldehyde condensate and the steric hindrance and lubricating effect of polyethylene glycol, a multi-dimensional dispersion network is formed, and the water reducing rate is significantly improved through the complementary and synergistic effect of chemical structure.

Description

Technical Field

[0001] This invention relates to the field of concrete water-reducing agent technology, and more specifically, to a concrete water-reducing agent and its preparation method. Background Technology

[0002] Concrete water-reducing agent is a chemical additive that can reduce the amount of mixing water while maintaining the slump of concrete. During concrete construction, by adding water-reducing agent, the amount of water used can be significantly reduced without significantly reducing the strength of concrete.

[0003] For example, CN111533481A discloses a novel concrete water-reducing agent and its preparation method. The formulation of this concrete water-reducing agent includes modified activated clay, defoamer, antifreeze agent, sodium bisulfite, potassium salt, isopropanol, air-entraining agent, and water. By adding an antifreeze agent to the raw materials, the freezing point of water inside the concrete is significantly lowered without precipitation, effectively improving the pore structure of the concrete and increasing its structural strength. Furthermore, the addition of an air-entraining agent greatly enhances the durability of the concrete and reduces slump loss. However, the presence of modified activated clay in this formulation means that clay minerals can adsorb water-reducing agent molecules, interfering with the dispersion effect of the water-reducing agent and reducing its ability to disperse cement particles. Increased dosage is required to compensate for the water-reducing effect, thus leading to a decrease in the water-reducing rate of the water-reducing agent.

[0004] To ensure the dispersion effect of the water-reducing agent and thus its water-reducing effect on concrete, a concrete water-reducing agent and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a concrete water-reducing agent and its preparation method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, one objective of this invention is to provide a concrete water-reducing agent, comprising the following raw materials in the following mass proportions:

[0007] The composition is as follows: 25-35% β-naphthalenesulfonate formaldehyde condensate, 5-9% aliphatic hydroxysulfonate formaldehyde condensate, 3-5% polyethylene glycol, 2-5% sodium carbonate, 1-3% dispersant, 1-3% defoamer, 2-5% antioxidant, and the balance is water.

[0008] As a further improvement to this technical solution, the defoamer is silicone oil.

[0009] As a further improvement to this technical solution, the antioxidant is sodium bisulfite.

[0010] As a further improvement to this technical solution, the dispersant is one of sodium lignosulfonate or polycarboxylic acid dispersant.

[0011] A second objective of this invention is to provide a method for preparing the aforementioned concrete water-reducing agent, comprising the following steps:

[0012] Step S1: Weigh the raw materials according to the mass ratio, and then prepare solutions of β-naphthalenesulfonate formaldehyde condensate and aliphatic hydroxysulfonate formaldehyde condensate respectively;

[0013] Subsequently, the β-naphthalenesulfonate formaldehyde condensate solution and the aliphatic hydroxysulfonate formaldehyde condensate solution were stirred and mixed to form the main chain base liquid;

[0014] Step S2: Dissolve polyethylene glycol in 60°C warm water, then add dispersant and stir until completely dissolved to obtain the additive solution;

[0015] Then, sodium carbonate and antioxidants are dissolved in the additive solution, and the additive solution is added to the main chain base liquid;

[0016] Step S3: Add defoamer to the main chain base liquid and stir for 10-15 minutes, then circulate the mixture through a high-pressure homogenizer to obtain the mother liquor;

[0017] The mother liquor is subjected to coarse filtration, fine filtration and deep purification to remove precipitated impurities;

[0018] Step S4: Remove excess water by vacuum distillation of the mother liquor and adjust the solid content of the mother liquor to obtain concrete water-reducing agent;

[0019] The concrete water-reducing agent is filtered through a 0.45μm filter membrane to remove impurities, and then filled and sealed.

[0020] As a further improvement to this technical solution, in step S1, the temperature during stirring and mixing is 40-50℃.

[0021] As a further improvement to this technical solution, in step S3, the pressure of the high-pressure homogenizer is 20-30 MPa, and the number of cycles is 2-3.

[0022] As a further improvement to this technical solution, in step S3, an antifoaming agent is added to the main chain base liquid at 30-40℃, and the stirring speed is 100-200 rpm.

[0023] As a further improvement to this technical solution, in step S3, coarse filtration is performed by using a plate and frame filter press or a bag filter to remove large particulate impurities from the mother liquor, fine filtration is performed by using membrane filtration to remove colloidal or micron-sized particles from the mother liquor, and deep purification is performed by centrifuging the mother liquor with a high-speed centrifuge to remove tiny impurities from the mother liquor.

[0024] As a further improvement to this technical solution, in step S4, the solid content of the mother liquor is adjusted to 30%-40% to obtain a concrete water-reducing agent.

[0025] In this invention, the strong electrostatic repulsion of β-naphthalenesulfonate formaldehyde condensate, the flexible adsorption of aliphatic hydroxysulfonate formaldehyde condensate, and the steric hindrance and lubrication of polyethylene glycol form a multidimensional dispersion network is formed, which significantly improves the water reduction rate through the complementary and synergistic effects of chemical structures.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In this concrete water-reducing agent and its preparation method, the sulfonic acid groups of the β-naphthalene sulfonate formaldehyde condensate and the aliphatic formaldehyde condensate provide strong electrostatic repulsion, while the long chains of polyethylene glycol further prevent particle aggregation through steric hindrance. The rigid naphthalene rings of the naphthalene system preferentially adsorb onto the surface of cement particles, and polyethylene glycol fills the uncovered areas to form a continuous adsorption layer. The synergistic adsorption of the two increases the surface coverage of cement particles. Furthermore, the rigid structure of the naphthalene system provides basic dispersing force at low temperatures, while the flexible chains of the aliphatic condensate maintain dispersing ability at high temperatures, thereby ensuring the dispersion effect of the water-reducing agent and further ensuring the water-reducing effect on concrete. Attached Figure Description

[0028] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] One objective of this invention is to provide a concrete water-reducing agent, comprising the following raw materials in the indicated mass proportions:

[0031] The composition is as follows: 25-35% β-naphthalenesulfonate formaldehyde condensate, 5-9% aliphatic hydroxysulfonate formaldehyde condensate, 3-5% polyethylene glycol, 2-5% sodium carbonate, 1-3% dispersant, 1-3% defoamer, 2-5% antioxidant, and the balance is water.

[0032] The defoamer is silicone oil, which forms fine dispersed particles in the liquid and continuously adsorbs surfactants, thus preventing foam formation.

[0033] Furthermore, the antioxidant is sodium bisulfite. Based on the reducing and antioxidant properties of sodium bisulfite, it can effectively inhibit oxidation reactions in concrete, thereby extending the service life of concrete.

[0034] Furthermore, the dispersant is either sodium lignosulfonate or polycarboxylic acid dispersant.

[0035] Please see Figure 1 As shown, a second objective of this invention is to provide a method for preparing the aforementioned concrete water-reducing agent, the specific steps of which are as follows:

[0036] Step S1: Weigh out 25-35% of β-naphthalenesulfonate formaldehyde condensate, 5-9% of aliphatic hydroxysulfonate formaldehyde condensate, 3-5% of polyethylene glycol, 2-5% of sodium carbonate, 1-3% of dispersant, 1-3% of defoamer, and 2-5% of antioxidant according to the mass ratio, with the remainder being water. Then, prepare solutions of β-naphthalenesulfonate formaldehyde condensate and aliphatic hydroxysulfonate formaldehyde condensate separately.

[0037] The defoamer is silicone oil, the antioxidant is sodium bisulfite, and the dispersant is either sodium lignosulfonate or polycarboxylic acid dispersant.

[0038] Subsequently, the β-naphthalenesulfonate formaldehyde condensate solution and the aliphatic hydroxysulfonate formaldehyde condensate solution were stirred and mixed to form a water-reducing main chain base liquid. The temperature during stirring and mixing was 40-50℃.

[0039] Step S2: Dissolve polyethylene glycol in 60°C warm water, then add dispersant and stir until completely dissolved to obtain the additive solution;

[0040] Sodium carbonate and antioxidants are then dissolved in the additive solution, and the additive solution is slowly added to the main chain base liquid.

[0041] Step S3: Add defoamer to the main chain base liquid at 30-40℃ and stir for 10-15 minutes at a stirring speed of 100-200 rpm to avoid bubble breakage. Then, circulate the solution through a high-pressure homogenizer to obtain the mother liquor. The pressure of the high-pressure homogenizer is 20-30 MPa, and the number of cycles is 2-3 to ensure that the components are evenly dispersed and there is no precipitation or stratification.

[0042] The mother liquor undergoes coarse filtration, fine filtration, and deep purification to remove precipitated impurities. Coarse filtration uses a plate and frame filter press or bag filter to remove large particulate impurities from the mother liquor. Fine filtration uses membrane filtration to remove colloidal or micron-sized particles from the mother liquor. Deep purification uses a high-speed centrifuge to separate and remove tiny impurities from the mother liquor.

[0043] Step S4: Remove excess water by vacuum distillation of the mother liquor, and adjust the solid content of the mother liquor to 30%-40% to obtain concrete water-reducing agent;

[0044] The concrete water-reducing agent is filtered through a 0.45μm filter membrane to remove impurities, and then filled and sealed.

[0045] The following specific embodiments will further illustrate the concrete water-reducing agent and its preparation method provided by the present invention.

[0046] Example 1

[0047] This embodiment proposes a method for preparing a concrete water-reducing agent, the specific steps of which are as follows:

[0048] Step S1: Weigh out 25% of β-naphthalenesulfonate formaldehyde condensate, 9% of aliphatic hydroxysulfonate formaldehyde condensate, 3% of polyethylene glycol, 5% of sodium carbonate, 1% of dispersant, 3% of defoamer, and 2% of antioxidant according to the mass ratio, with the remainder being water. Then, prepare solutions of β-naphthalenesulfonate formaldehyde condensate and aliphatic hydroxysulfonate formaldehyde condensate separately.

[0049] The defoamer is silicone oil, the antioxidant is sodium bisulfite, and the dispersant is sodium lignosulfonate.

[0050] Subsequently, the β-naphthalenesulfonate formaldehyde condensate solution and the aliphatic hydroxysulfonate formaldehyde condensate solution were stirred and mixed to form the main chain base liquid. The temperature during stirring and mixing was 50°C.

[0051] Step S2: Dissolve polyethylene glycol in 60°C warm water, then add dispersant and stir until completely dissolved to obtain the additive solution;

[0052] Sodium carbonate and antioxidants are then dissolved in the additive solution, and the additive solution is slowly added to the main chain base liquid.

[0053] Step S3: Add defoamer to the main chain base liquid at 30℃ and stir for 15 minutes at a stirring speed of 100 rpm. Then, circulate the solution through a high-pressure homogenizer to obtain the mother liquor. The pressure of the high-pressure homogenizer is 30 MPa and the number of cycles is 2.

[0054] The mother liquor undergoes coarse filtration, fine filtration, and deep purification to remove precipitated impurities. Coarse filtration uses a plate and frame filter press or bag filter to remove large particulate impurities from the mother liquor. Fine filtration uses membrane filtration to remove colloidal or micron-sized particles from the mother liquor. Deep purification uses a high-speed centrifuge to separate and remove tiny impurities from the mother liquor.

[0055] Step S4: Remove excess water by vacuum distillation of the mother liquor, and adjust the solid content of the mother liquor to 40% to obtain concrete water-reducing agent;

[0056] The concrete water-reducing agent is filtered through a 0.45μm filter membrane to remove impurities, and then filled and sealed.

[0057] Example 2

[0058] This embodiment proposes a method for preparing a concrete water-reducing agent, the specific steps of which are as follows:

[0059] Step S1: Weigh out 30% of β-naphthalenesulfonate formaldehyde condensate, 8% of aliphatic hydroxysulfonate formaldehyde condensate, 4% of polyethylene glycol, 3% of sodium carbonate, 2% of dispersant, 2% of defoamer, and 4% of antioxidant according to the mass ratio, with the remainder being water. Then, prepare solutions of β-naphthalenesulfonate formaldehyde condensate and aliphatic hydroxysulfonate formaldehyde condensate separately.

[0060] The defoamer is silicone oil, the antioxidant is sodium bisulfite, and the dispersant is either sodium lignosulfonate or polycarboxylic acid dispersant.

[0061] Subsequently, the β-naphthalenesulfonate formaldehyde condensate solution and the aliphatic hydroxysulfonate formaldehyde condensate solution were stirred and mixed to form the main chain base liquid. The temperature during stirring and mixing was 45℃.

[0062] Step S2: Dissolve polyethylene glycol in 60°C warm water, then add dispersant and stir until completely dissolved to obtain the additive solution;

[0063] Sodium carbonate and antioxidants are then dissolved in the additive solution, and the additive solution is slowly added to the main chain base liquid.

[0064] Step S3: Add defoamer to the main chain base liquid at 35℃ and stir for 12 minutes at a stirring speed of 150 rpm. Then, circulate the solution through a high-pressure homogenizer to obtain the mother liquor. The pressure of the high-pressure homogenizer is 25 MPa, and the number of cycles is 3.

[0065] The mother liquor undergoes coarse filtration, fine filtration, and deep purification to remove precipitated impurities. Coarse filtration uses a plate and frame filter press or bag filter to remove large particulate impurities from the mother liquor. Fine filtration uses membrane filtration to remove colloidal or micron-sized particles from the mother liquor. Deep purification uses a high-speed centrifuge to separate and remove tiny impurities from the mother liquor.

[0066] Step S4: Remove excess water by vacuum distillation of the mother liquor, and adjust the solid content of the mother liquor to 35% to obtain concrete water-reducing agent.

[0067] The concrete water-reducing agent is filtered through a 0.45μm filter membrane to remove impurities, and then filled and sealed.

[0068] Example 3

[0069] This embodiment proposes a method for preparing a concrete water-reducing agent, the specific steps of which are as follows:

[0070] Step S1: Weigh out 35% of β-naphthalenesulfonate formaldehyde condensate, 5% of aliphatic hydroxysulfonate formaldehyde condensate, 5% of polyethylene glycol, 2% of sodium carbonate, 3% of dispersant, 1% of defoamer, and 5% of antioxidant according to the mass ratio, with the remainder being water. Then, prepare solutions of β-naphthalenesulfonate formaldehyde condensate and aliphatic hydroxysulfonate formaldehyde condensate separately.

[0071] The defoamer is silicone oil, the antioxidant is sodium bisulfite, and the dispersant is one of the polycarboxylic acid dispersants.

[0072] Subsequently, the β-naphthalenesulfonate formaldehyde condensate solution and the aliphatic hydroxysulfonate formaldehyde condensate solution were stirred and mixed to form the main chain base liquid. The temperature during stirring and mixing was 40℃.

[0073] Step S2: Dissolve polyethylene glycol in 60°C warm water, then add dispersant and stir until completely dissolved to obtain the additive solution;

[0074] Sodium carbonate and antioxidants are then dissolved in the additive solution, and the additive solution is slowly added to the main chain base liquid.

[0075] Step S3: Add defoamer to the main chain base liquid at 40℃ and stir for 10 minutes at a stirring speed of 200 rpm. Then, circulate the mother liquor through a high-pressure homogenizer at a pressure of 20 MPa and circulate it 3 times.

[0076] The mother liquor undergoes coarse filtration, fine filtration, and deep purification to remove precipitated impurities. Coarse filtration uses a plate and frame filter press or bag filter to remove large particulate impurities from the mother liquor. Fine filtration uses membrane filtration to remove colloidal or micron-sized particles from the mother liquor. Deep purification uses a high-speed centrifuge to separate and remove tiny impurities from the mother liquor.

[0077] Step S4: Remove excess water by vacuum distillation of the mother liquor, and adjust the solid content of the mother liquor to 30% to obtain concrete water-reducing agent;

[0078] The concrete water-reducing agent is filtered through a 0.45μm filter membrane to remove impurities, and then filled and sealed.

[0079] Concrete water-reducing agents were prepared according to the preparation methods provided in Examples 1-3. The water reduction rate of the concrete water-reducing agent was then measured according to GB8076-2008 Concrete Admixtures. Specifically, the water reduction rate was calculated by comparing the water consumption difference between the reference concrete and the concrete with the admixture. The calculation formula is as follows:

[0080]

[0081] In the formula, WR is the water reduction rate, W0 is the unit water consumption of the reference concrete, and W1 is the unit water consumption of the concrete using the concrete water-reducing agent. The measured results are recorded in Table 1.

[0082] Table 1 shows the water reduction rates of the concrete water-reducing agents prepared in Examples 1-3.

[0083] Example 1 Example 2 Example 3 Water reduction rate / % 27 30 29

[0084] As shown in Table 1, the water reduction rate of the concrete water-reducing agents prepared in Examples 1-3 is all higher than 27%, indicating that the method for preparing a concrete water-reducing agent provided by the present invention can produce a concrete water-reducing agent with good water reduction effect.

[0085] In this invention, the sulfonic acid group (-SO3) of the β-naphthalenesulfonate formaldehyde condensate... - Adsorbed on the surface of cement particles, the strong negative charge repulsion inhibits particle agglomeration, and the rigid structure of the naphthalene ring forms a physical barrier on the particle surface, preventing secondary aggregation caused by van der Waals forces; the sulfonic acid groups of the aliphatic hydroxysulfonate formaldehyde condensate provide electrostatic repulsion, and the hydroxyl groups bind to the CaO on the surface of cement particles through hydrogen bonds. 2+ The combination enhances adsorption stability, and the flexibility of the aliphatic hydroxysulfonate formaldehyde condensate's aliphatic chains allows it to effectively disperse particles even in high-temperature or high-alkaline environments. The long polyethylene glycol chains adsorb onto the particle surface, preventing particles from approaching each other through volume repulsion. At the same time, the ether bonds form a hydration film with water molecules, reducing inter-particle friction and improving fluidity.

[0086] In summary, the sulfonic acid groups of both β-naphthalene sulfonate formaldehyde condensate and aliphatic formaldehyde condensate provide strong electrostatic repulsion, while the long chains of polyethylene glycol further prevent particle aggregation through steric hindrance. The rigid naphthalene rings of the naphthalene system preferentially adsorb onto the surface of cement particles, and polyethylene glycol fills the uncovered areas, forming a continuous adsorption layer. The synergistic adsorption of the two increases the surface coverage of cement particles. Furthermore, the rigid structure of the naphthalene system provides basic dispersing force at low temperatures, while the flexible chains of the aliphatic condensate maintain dispersing ability at high temperatures, thus ensuring the dispersion effect of the water-reducing agent and further ensuring the water-reducing effect on concrete.

[0087] Example 4

[0088] To verify that the composition of β-naphthalenesulfonate formaldehyde condensate and its mass percentage of 25-35% in the concrete water-reducing agent are important factors in achieving a high water reduction rate in the concrete water-reducing agent prepared in this invention, this embodiment, based on the above embodiment 2, sets the mass percentage of β-naphthalenesulfonate formaldehyde condensate in the concrete water-reducing agent to 0%, 5%, 10%, 25%, 30%, 35%, or 40%, and then prepares the concrete water-reducing agent. The water reduction rate is then tested according to the water reduction rate test method in the above embodiment, and the test results are recorded in Table 2.

[0089] Table 2 Comparison of water reduction rates of water-reducing agents with different mass percentages of β-naphthalenesulfonate formaldehyde condensate.

[0090] β-Naphthalenesulfonate formaldehyde condensate mass percentage / % 0 5 10 25 30 35 40 Water reduction rate / % 8 14 21 28 30 30 19

[0091] As shown in Table 2, when the mass percentage of β-naphthalenesulfonate formaldehyde condensate in the concrete water-reducing agent is 0%, 5%, 10%, or 40%, i.e., not 25-35%, the water reduction rate of the prepared concrete water-reducing agent decreases significantly. This indicates that the composition of β-naphthalenesulfonate formaldehyde condensate and its mass percentage of 25-35% in the concrete water-reducing agent are one of the important factors contributing to the high water reduction rate of the concrete water-reducing agent prepared in this invention.

[0092] Secondly, in order to verify that the aliphatic hydroxysulfonate formaldehyde condensate composition and its 5-9% mass proportion in the concrete water-reducing agent are important factors in achieving a high water reduction rate in the concrete water-reducing agent prepared in this invention, this embodiment, based on the above embodiment 2, sets the mass proportion of the aliphatic hydroxysulfonate formaldehyde condensate in the concrete water-reducing agent to 0%, 2%, 4%, 5%, 8%, 9%, or 12%, and then prepares the concrete water-reducing agent. The water reduction rate is then tested according to the water reduction rate test method in the above embodiment, and the test results are recorded in Table 3.

[0093] Table 3 Comparison of water-reducing agent water reduction rates when the mass percentage of formaldehyde condensate with different aliphatic hydroxysulfonate condensates is reached.

[0094]

[0095]

[0096] As shown in Table 3, when the mass percentage of aliphatic hydroxysulfonate formaldehyde condensate in the concrete water-reducing agent is 0%, 2%, 4%, or 12%, i.e., not 5-9%, the water reduction rate of the prepared concrete water-reducing agent decreases significantly. This indicates that the aliphatic hydroxysulfonate formaldehyde condensate component and its mass percentage of 5-9% in the concrete water-reducing agent are important factors contributing to the high water reduction rate of the concrete water-reducing agent prepared in this invention.

[0097] Finally, to verify that the polyethylene glycol content and its 3-5% mass percentage in the concrete water-reducing agent are important factors contributing to the high water reduction rate of the concrete water-reducing agent prepared in this invention, this embodiment, based on the above embodiment 2, sets the mass percentage of polyethylene glycol in the concrete water-reducing agent to 0%, 1%, 2%, 3%, 4%, 5%, or 6%, and then prepares the concrete water-reducing agent. The water reduction rate test method described in the above embodiment is then used for testing, and the test results are recorded in Table 4.

[0098] Table 4 Comparison of water reduction rates of water-reducing agents with different polyethylene glycol mass percentages.

[0099] Polyethylene glycol mass percentage / % 0 1 2 3 4 5 6 Water reduction rate / % 11 15 22 29 30 28 23

[0100] As shown in Table 4, when the mass percentage of polyethylene glycol in the concrete water-reducing agent is 0%, 1%, 2%, or 6%, i.e., not 3-5%, the water reduction rate of the prepared concrete water-reducing agent decreases significantly. This indicates that the polyethylene glycol content and its mass percentage of 3-5% in the concrete water-reducing agent are one of the important factors contributing to the high water reduction rate of the concrete water-reducing agent prepared in this invention.

[0101] Example 5

[0102] The concrete water-reducing agent is produced according to the method provided in the above embodiments, and then tested according to the water reduction rate test method provided in the above embodiments.

[0103] Experiments show that, under the conditions of this embodiment, the concrete water-reducing agent has a high water reduction rate, indicating that the concrete water-reducing agent produced by the preparation method provided by this invention has a good water-reducing effect on concrete.

[0104] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a concrete water reducing agent, characterized by, The method comprises the following steps: Step S1: weighing β-naphthalene sulfonate formaldehyde condensate 25-35%, aliphatic hydroxyl sulfonate formaldehyde condensate 5-9%, polyethylene glycol 3-5%, sodium carbonate 2-5%, dispersant 1-3%, defoaming agent 1-3%, antioxidant 2-5% by mass ratio, and then preparing β-naphthalene sulfonate formaldehyde condensate and aliphatic hydroxyl sulfonate formaldehyde condensate into solutions respectively; Then the β-naphthalene sulfonate formaldehyde condensate solution and the aliphatic hydroxyl sulfonate formaldehyde condensate solution are stirred and mixed to form a main chain base solution; Step S2: dissolving polyethylene glycol in 60°C warm water, then adding a dispersant and stirring until completely dissolved to obtain an additive solution; Then the sodium carbonate and the antioxidant are dissolved in the additive solution, and then the additive solution is added to the main chain base solution; Step S3: adding the defoaming agent to the main chain base solution and stirring for 10-15 min, and then treating by a high-pressure homogenizer to obtain a mother liquor; The mother liquor is treated by coarse filtration, fine filtration and deep purification to remove precipitated impurities in the mother liquor; Step S4: removing excess water from the mother liquor by vacuum distillation to adjust the solid content of the mother liquor to obtain a concrete water reducing agent; The concrete water reducing agent is filtered through a 0.45 μm filter membrane to remove impurities, and then is filled and sealed.

2. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S1, the defoaming agent is silicone oil.

3. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S1, the antioxidant is sodium bisulfite.

4. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S1, the dispersant is one of sodium lignosulfonate or polycarboxylic acid dispersant.

5. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S1, the temperature during stirring and mixing is 40-50°C.

6. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S3, the pressure during treatment by the high-pressure homogenizer is 20-30 MPa, and the number of cycle treatments is 2-3 times.

7. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S3, the defoaming agent is added to the main chain base solution at 30-40°C, and the stirring speed is 100-200 rpm.

8. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S3, the coarse filtration is to remove large particle impurities in the mother liquor by using a plate and frame filter press or a bag filter, the fine filtration is to remove colloidal or micron-sized particles in the mother liquor by using membrane filtration, and the deep purification treatment is to remove small impurities in the mother liquor by centrifugal separation by a high-speed centrifuge.

9. The method for preparing the concrete water-reducing agent according to claim 1, characterized in that: In the step S4, the concrete water reducing agent is obtained after the solid content of the mother liquor is adjusted to 30%-40%.

10. The concrete water reducing agent prepared by the preparation method according to any one of claims 1-9.

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