Water-resistant magnesium phosphate cement-based material and preparation method thereof

Abstract

The invention relates to a water-resistant magnesium phosphate cement-based material which comprises the following components: magnesium oxide, a composite phosphate compound, borax, a sodium silicate solution, water, a polyethylene glycol derivative, polyacrylamide and an ammonium sulfate solution. According to the water-resistant magnesium phosphate cement-based material, precipitation of water can be controlled in the preparation process, so that the speed of a hydration reaction is conveniently controlled, and the situation that phosphate is fixed in a matrix and cannot continue to participate in the reaction due to the fact that the hydration reaction is too fast is avoided; according to the water-resistant magnesium phosphate cement-based material, the fluidity of a mixture can be better in the preparation process, so that the mixture can be stirred and mixed more sufficiently, and the polyethylene glycol derivative can introduce bubbles to block capillary pore channels in concrete; therefore, permeation of external water can be reduced in the using process of the water-resistant magnesium phosphate cement-based material.

Description

Technical Field

[0001] The present application relates to the technical field of magnesium phosphate cement, and in particular to a water-resistant magnesium phosphate cement-based material and a preparation method thereof. Background Art

[0002] Magnesium phosphate cement has a hydration mechanism and hydration products that are completely different from those of ordinary Portland cement, and is a new type of cementitious material with broad application prospects. Traditional magnesium phosphate cement is a new type of material with phosphate as the bonding phase, which is prepared by mixing MgO, soluble phosphate, retarding material and mineral admixture in a certain proportion.

[0003] However, the current magnesium phosphate cement has the following problems: the hydration reaction is highly exothermic during its preparation, and the hydration is rapid and difficult to control, so that the hydration reaction is mainly an in-situ reaction. A large amount of phosphate that does not participate in the hydration reaction in the early stage of hydration is fixed inside the matrix and cannot continue to participate in the reaction, so that there are soluble phosphates inside the matrix of magnesium phosphate cement-based materials. This makes the soluble phosphate dissolve when the magnesium phosphate cement-based material is eroded by water, which will cause the pores inside the matrix to increase and the strength of the matrix to decrease; and when external water penetrates into the matrix, the phosphate that did not participate in the hydration in the early stage will continue to react with the unreacted magnesium oxide, so that internal stress is generated inside the matrix, causing the performance of the matrix to decline in all aspects. Summary of the invention

[0004] In order to improve the problems raised in the above background technology, the present application provides a water-resistant magnesium phosphate cement-based material and a preparation method thereof.

[0005] The present application provides a water-resistant magnesium phosphate cement-based material using the following technical solution: A water-resistant magnesium phosphate cement-based material, the components of which include magnesium oxide, a composite phosphate compound, borax, a sodium silicate solution, water, a polyethylene glycol derivative, polyacrylamide and an ammonium sulfate solution, and the water-resistant magnesium phosphate cement-based material is obtained by using the following materials in parts by mass: 1-2 parts of polyethylene glycol derivatives; 1-2 parts of polyacrylamide; 1 to 5 parts of ammonium sulfate solution; 1 to 5 parts of sodium silicate solution; 1 to 5 parts of borax; 10-20 parts water; 20-40 parts of composite phosphoric acid compound; 30-50 parts of magnesium oxide.

[0006] Furthermore, the polyethylene glycol derivatives include one or a mixture of polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, dodecyl heptapolyethylene glycol ether, phospholipid polyethylene glycol hydroxyl, and polyethylene glycol monomethyl ether.

[0007] Furthermore, the concentration of the ammonium sulfate solution is set to 40%-50%.

[0008] Furthermore, the concentration of the sodium silicate solution is set to 5%-10%.

[0009] The present application provides a method for preparing a water-resistant magnesium phosphate cement-based material using the following technical solution: A method for preparing a water-resistant magnesium phosphate cement-based material comprises the following steps: Step 1, collecting wastewater from a phosphoric acid plant and excess sludge from a domestic sewage treatment plant and preparing a composite phosphoric acid compound; Step 2, weighing magnesium oxide, composite phosphate compound, water, borax, sodium silicate solution, polyethylene glycol derivatives, polyacrylamide, and ammonium sulfate solution according to the ratio and mixing them; Step 3, before performing step 2, first mixing the polyacrylamide and the polyethylene glycol derivative with water; Step 4, while carrying out step 2, adding the ammonium sulfate solution to the mixture in batches; Step 5: During step 4, the mixture is stirred.

[0010] Furthermore, the specific preparation process of the composite phosphate compound in step 1 is as follows: Step 11, collecting wastewater from a phosphoric acid plant and excess sludge from a domestic sewage treatment plant, mixing them in equal mass ratios to obtain a mixture, charging the mixture into a reactor, heating the mixture to 70-80° C., and stirring the reaction for 12 hours; Step 12, after the reaction is completed, filter and separate to obtain a filtrate, add sodium sulfide solution dropwise to the filtrate until no more precipitate is generated in the filtrate, filter and remove the precipitate to obtain a secondary filtrate; Step 13, adding calcium hydroxide powder to the secondary filtrate, wherein the mass ratio of the secondary filtrate to calcium hydroxide is 5:1, and stirring the reaction for 10-15 minutes to obtain a mixed suspension; Step 14: add anhydrous ethanol to the mixed suspension, and the mass ratio of the mixed suspension to the anhydrous ethanol is 1:2, continue stirring and reacting for 1-2 hours, and filter to obtain a filter cake, which is the composite phosphate compound.

[0011] Furthermore, the specific preparation process of mixing polyacrylamide and polyethylene glycol derivatives with water in step 3 is as follows: Step 31, injecting clean water in the required mass fraction into the reaction kettle according to the proportion and continuously stirring the clean water; Step 32: While stirring, slowly and dispersedly sprinkle polyacrylamide into the reaction kettle, and continue stirring for a period of time until the polyacrylamide particles are completely dissolved to form a uniform, transparent, viscous solution; Step 33: After the polyacrylamide is completely dissolved, continue stirring and slowly add the polyethylene glycol derivative to evenly disperse it in the water until a uniformly mixed solution is formed.

[0012] Furthermore, in step 4, the ammonium sulfate solution is added to the mixture by dripping or spraying to avoid excessive local concentration, and in step 4, the temperature of the mixture is controlled to 20-40°C by an electric heater, and the temperature of the mixture is gradually increased.

[0013] The beneficial technical effect of the present application is: by coordinating the polyacrylamide and the ammonium sulfate solution in the water-resistant magnesium phosphate cement-based material, the water precipitation of the water-resistant magnesium phosphate cement-based material can be controlled during the preparation process, thereby facilitating the control of the speed of the hydration reaction, thereby avoiding the phosphate being fixed inside the matrix and unable to continue to participate in the reaction due to the too fast hydration reaction; By setting the polyethylene glycol derivatives in the water-resistant magnesium phosphate cement-based material, the fluidity of the mixture can be improved during the preparation of the water-resistant magnesium phosphate cement-based material, so that the mixture can be stirred and mixed more fully; and the polyethylene glycol derivatives can introduce bubbles to block the capillary channels inside the concrete, so that the infiltration of external water bodies can be reduced during the use of the water-resistant magnesium phosphate cement-based material. DETAILED DESCRIPTION

[0014] The technical solution of the present application is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0015] The embodiments of the present application disclose a water-resistant magnesium phosphate cement-based material and a preparation method thereof.

[0016] The components of the water-resistant magnesium phosphate cement-based material include magnesium oxide, composite phosphoric acid compound, borax, sodium silicate solution, water, polyethylene glycol derivatives, polyacrylamide and ammonium sulfate solution. When the above components are used to process and prepare the water-resistant magnesium phosphate cement-based material, the following mass fractions can be used: 1 to 2 parts of polyethylene glycol derivatives, 1 to 2 parts of polyacrylamide, 1 to 5 parts of ammonium sulfate solution with a concentration of 40%-50%, 1 to 5 parts of sodium silicate solution with a concentration of 5%-10%, 1 to 5 parts of borax, 10 to 20 parts of water, 20 to 40 parts of composite phosphoric acid compound, and 30 to 50 parts of magnesium oxide.

[0017] In this embodiment, the polyethylene glycol derivative is a compound with a longer molecular chain and more functional groups. The polyethylene glycol derivative can be obtained by mixing one or more of polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, dodecyl heptapolyethylene glycol ether, phospholipid polyethylene glycol hydroxyl, and polyethylene glycol monomethyl ether. The above compounds all have hydrophilic groups and hydrophobic groups. When they are added to the mixture, the hydrophilic groups will face the water phase, while the hydrophobic groups will face the gas phase, thereby forming a stable film on the surface of the bubbles. This film can prevent the bubbles from breaking or merging during the mixing and pouring process, thereby ensuring that the bubbles are small, stable and evenly distributed in the concrete. The bubbles introduced by the above compounds play a role similar to "balls" in the mixture, reducing the friction between particles, thereby improving the fluidity of the mixture. This makes the mixture smoother during the mixing process, so that the phosphates in the hydration reaction process are easier to fully contact with water.

[0018] In this embodiment, polyacrylamide is a non-ionic polymer formed by polymerization reaction, which has strong adsorption capacity and can quickly absorb surrounding water. After polyacrylamide (PAM) absorbs water, a large number of water molecules and polyacrylamide molecular chains will form inside it, so that the water is firmly adsorbed in the polyacrylamide molecular network, avoiding excessive water from reacting with phosphate during the mixing process of the components, thereby causing rapid hydration.

[0019] In this embodiment, in order to utilize the salting-out effect to slowly precipitate water in the system after polyacrylamide absorbs water, an ammonium sulfate solution is added. Ammonium sulfate solution is an effective salting-out agent, which can destroy the hydrogen bond interaction between water molecules and polyacrylamide molecular chains to precipitate water from the PAM network. By controlling the amount and speed of ammonium sulfate addition, the precipitation of water molecules in the polyacrylamide molecular network can be controlled to a certain extent during the preparation process, thereby achieving the purpose of controlling the water reaction to proceed more slowly.

[0020] In the prior art, borax is often added as a retarder. Borax can assist in adjusting the hydration reaction rate of magnesium phosphate cement and prolong the setting time. The retarding mechanism of borax is mainly based on the formation of complexes between the borate in its molecules and the magnesium ions in the cement solution, and the formation of an amorphous isolation layer on the surface of cement particles. This isolation layer delays the hydration and crystallization process of cement, thereby prolonging the setting time of cement.

[0021] In the prior art, sodium silicate solution is often used to improve the water resistance and matrix strength of magnesium phosphate cement-based materials. Sodium silicate solution can also react chemically with other components in cement to generate more stable compounds, which are not easily soluble in water, thereby enhancing the water resistance of cement. The silicate ions in the sodium silicate solution can also combine with magnesium ions in cement to form silicate minerals, which have high hardness and strength and can enhance the mechanical properties of the cement matrix.

[0022] According to the above embodiments, an experiment can be designed to test the performance of water-resistant magnesium phosphate cement-based materials and traditional magnesium phosphate cement, and the purpose of the experiment is to verify whether the water resistance and matrix strength of the new material are better than those of the traditional material by comparing the traditional magnesium phosphate cement-based material with the water-resistant magnesium phosphate cement-based material provided by the present invention.

[0023] Experimental group and control group settings: The experimental group adopts the water-resistant magnesium phosphate cement-based material provided by the present invention. According to different proportions of components, three experimental groups are set, respectively recorded as experimental group A, experimental group B and experimental group C. The control group adopts a cement-based material prepared by a traditional magnesium phosphate cement-based material and a preparation method thereof, without adding polyethylene glycol derivatives, polyacrylamide and ammonium sulfate solution, and the other components are the same as those of the experimental group.

[0024] Experimental group A: 35 parts of magnesium oxide, 35 parts of complex phosphate compound, 3 parts of borax, 3 parts of sodium silicate solution, 1 part of polyethylene glycol derivative (polyethylene glycol methacrylate), 1 part of polyacrylamide, 2 parts of 45% ammonium sulfate solution, and 20 parts of water.

[0025] Experimental group B: 35 parts of magnesium oxide, 35 parts of complex phosphoric acid compound, 3 parts of borax, 3 parts of sodium silicate solution, 2 parts of polyethylene glycol derivatives (polyethylene glycol methacrylate), 1 part of polyacrylamide, 2 parts of 45% ammonium sulfate solution, and 19 parts of water.

[0026] Experimental group C: 35 parts of magnesium oxide, 35 parts of complex phosphoric acid compound, 3 parts of borax, 3 parts of sodium silicate solution, 1 part of polyethylene glycol derivative (polyethylene glycol methacrylate), 2 parts of polyacrylamide, 2 parts of 45% ammonium sulfate solution, and 19 parts of water.

[0027] Control group: 35 parts of magnesium oxide, 35 parts of complex phosphate compound, 3 parts of borax, 3 parts of sodium silicate solution, and 24 parts of water.

[0028] Experimental conditions: The temperature was controlled at room temperature (about 25°C), the stirring speed was 300 r / min, and the stirring time was 30 min.

[0029] Experimental steps and process: When conducting the water resistance test, the cement-based materials of the experimental group and the control group were prepared into test blocks of standard size, and then the test blocks were immersed in clean water at room temperature to ensure that the test blocks were completely immersed. After immersion for 7 days, the test blocks were taken out, and the surface moisture was gently wiped with a clean towel, and then the mass of the test blocks before and after immersion was weighed using an electronic balance to calculate the mass loss rate.

[0030] When conducting the matrix strength test, the cement-based materials of the experimental group and the control group are prepared into test blocks of standard size, and then the test blocks are placed under standard curing conditions and cured to a specified age (such as 28 days). The test blocks are then tested for compressive strength using a universal material testing machine, the maximum failure load is recorded, and the compressive strength is calculated based on the size of the test blocks and the maximum failure load.

[0031] Experimental results:

[0032] Experimental results analysis: The water-resistant magnesium phosphate cement-based materials (experimental groups A, B, and C) provided by the present invention are superior to the traditional magnesium phosphate cement-based materials (control group) in terms of water resistance and matrix strength.

[0033] Among the three experimental groups, experimental group C performed best in water resistance and matrix strength. Although the water resistance and matrix strength of experimental groups B and C were slightly lower than those of experimental group A, they were still significantly better than those of the control group, indicating that the cement-based material provided by the present invention has good performance under different component proportions.

[0034] The preparation method of water-resistant magnesium phosphate cement-based material is as follows: Step 1, collecting the wastewater from the phosphoric acid plant and the residual sludge from the domestic sewage treatment plant and preparing the composite phosphoric acid compound. In the preparation process of the composite phosphoric acid compound, the wastewater from the phosphoric acid plant and the residual sludge from the domestic sewage treatment plant are first collected, and the mixture is uniformly mixed in an equal mass ratio to obtain a mixture, and the mixture is loaded into a reactor, heated to 70-80 ° C, and stirred for 12 hours; then filtered after the reaction is completed, the filtrate is separated to obtain a filtrate, and a sodium sulfide solution is added dropwise to the filtrate until no more precipitation is produced in the filtrate, and the precipitation is filtered to obtain a secondary filtrate; then calcium hydroxide powder is added to the secondary filtrate, and the mass ratio of the secondary filtrate to calcium hydroxide is 5: 1, and the reaction is stirred for 10-15 minutes to obtain a mixed suspension; finally, anhydrous ethanol is added to the mixed suspension, and the mass ratio of the mixed suspension to anhydrous ethanol is 1: 2, and the reaction is continued to be stirred for 1-2 hours, and the filter cake is obtained by filtering, which is the composite phosphoric acid compound.

[0035] Step 2, mixing the polyacrylamide and the polyethylene glycol derivative with water. In this process, the required mass fraction of clean water is injected into the reactor according to the ratio and the clean water is continuously stirred to form a vortex in the clean water; then, while stirring, the polyacrylamide is slowly and dispersedly sprinkled into the reactor, and stirring is continued for a period of time until the polyacrylamide particles are completely dissolved to form a uniform, transparent, viscous solution; finally, after the polyacrylamide is completely dissolved, stirring is continued, and the polyethylene glycol derivative is slowly added to be uniformly dispersed in the water until a uniform mixture is formed.

[0036] Step 3, weighing magnesium oxide, composite phosphate compound, water, borax, sodium silicate solution, polyethylene glycol derivative and the mixture in step 2 according to the proportion and mixing; Step 4, when performing step 3, ammonium sulfate solution is added to the mixture in batches, and the mixture is stirred in the process. The ammonium sulfate solution can be added to the mixture in a dripping or spraying manner to avoid excessive local concentration. In addition, the temperature of the mixture can be controlled to 20-40°C by an electric heater during the addition of the ammonium sulfate solution to the mixture, and the temperature of the mixture is gradually increased. Thereby, the water molecules in the polyacrylamide molecular network are precipitated by the addition of the ammonium sulfate solution and the raising of the temperature.

[0037] According to the above preparation method, an experiment can be designed, and by controlling the amount and frequency of addition of ammonium sulfate solution, the performance of the prepared water-resistant magnesium phosphate cement-based material can be compared.

[0038] Experimental Materials: The basic components of water-resistant magnesium phosphate cement-based materials are: magnesium oxide, complex phosphate compounds, borax, sodium silicate solution, water, polyethylene glycol derivatives (such as polyethylene glycol methacrylate), and polyacrylamide.

[0039] Ammonium sulfate solution, fixed concentration at 45%.

[0040] Experimental groups: Basic preparation: According to the preparation method of water-resistant magnesium phosphate cement-based materials, a composite phosphate compound is first prepared, and polyacrylamide and polyethylene glycol derivatives are evenly mixed with water.

[0041] Variable settings: Two groups of variables are set for the amount of ammonium sulfate solution added, adding 1 and 2 parts of ammonium sulfate solution (based on the percentage of the total mass fraction); three groups are set for the frequency of adding ammonium sulfate solution, adding once, adding three times, and adding five times. According to the above variable settings, six experimental groups can be obtained, namely: Experimental group A: the amount of ammonium sulfate solution added was 1 portion, and the total frequency of addition was 1 time; Experimental group B: the amount of ammonium sulfate solution added was 1 part, and the total frequency of addition was 3 times; Experimental group C: the amount of ammonium sulfate solution added was 1 portion, and the total frequency of addition was 5 times; Experimental group D: the amount of ammonium sulfate solution added was 2 parts, and the total frequency of addition was 1 time; Experimental group E: the amount of ammonium sulfate solution added was 2 parts, and the total frequency of addition was 3 times; Experimental group F: The amount of ammonium sulfate solution added was 2 portions, and the total frequency of addition was 5 times.

[0042] Other ingredients: Keep the added amounts of magnesium oxide, complex phosphate compounds, borax, sodium silicate solution, water, polyethylene glycol derivatives and polyacrylamide unchanged.

[0043] Experimental process: Mixing and curing: Weigh each component according to the ratio and mix. During the mixing process, add ammonium sulfate solution according to the set addition amount and continue stirring until the reaction is complete. Pour the mixed material into the mold for molding, and then cure it under standard curing conditions to the specified age (such as 28 days).

[0044] Compressive strength test: Use a universal material testing machine to test the compressive strength of the test blocks after curing, record the maximum failure load, and calculate the compressive strength based on the size of the test blocks.

[0045] Water resistance test: Soak the test block in clean water at room temperature for a certain period of time (such as 7 days), take out the test block and wipe off the moisture on the surface, then weigh the mass of the test block and calculate the mass loss rate to evaluate its water resistance.

[0046] Experimental results:

[0047] Experimental results analysis: When the amount of ammonium sulfate solution added increased from 1 to 2 parts, the mass loss rate decreased regardless of the frequency of addition, indicating that water resistance was improved. At the same time, the compressive strength also increased with the increase in the amount of ammonium sulfate solution added, indicating that the addition of ammonium sulfate helps to improve the mechanical properties of cement-based materials.

[0048] At the same amount of ammonium sulfate solution added, as the frequency of addition increases, the mass loss first decreases and then increases, indicating that multiple additions of ammonium sulfate solution can be better dispersed in cement-based materials and promote the uniform hydration reaction; however, as the frequency of addition increases, the addition time will also become longer, which will also have a certain adverse effect on the hydration reaction. In addition, the compressive strength also increases first and then decreases with the increase in the frequency of addition, indicating that multiple additions of ammonium sulfate solution can be better dispersed in cement-based materials and promote the uniform hydration reaction; however, as the frequency of addition increases, the addition time will also become longer, which will also have a certain adverse effect on the hydration reaction, and then affect the compressive strength. However, regardless of the frequency of addition, the water resistance and compressive strength are better than those of traditional magnesium phosphate cement materials.

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A water-resistant magnesium phosphate cement-based material, whose components include magnesium oxide, composite phosphate compound, borax, sodium silicate solution and water, characterized in that: Its components also include polyethylene glycol derivatives, polyacrylamide and ammonium sulfate solution, and the water-resistant magnesium phosphate cement-based material adopts the following materials in parts by weight: 1-2 parts of polyethylene glycol derivatives; 1-2 parts of polyacrylamide; 1 to 5 parts of ammonium sulfate solution; 1 to 5 parts of sodium silicate solution; 1 to 5 parts of borax; 10-20 parts water; 20-40 parts of composite phosphoric acid compound; 30-50 parts of magnesium oxide.

2. A water-resistant magnesium phosphate cement-based material according to claim 1, characterized in that: The polyethylene glycol derivatives include one or a mixture of polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, dodecyl heptapolyethylene glycol ether, phospholipid polyethylene glycol hydroxyl, and polyethylene glycol monomethyl ether.

3. A water-resistant magnesium phosphate cement-based material according to claim 1, characterized in that: The concentration of the ammonium sulfate solution is set to 40%-50%.

4. A water-resistant magnesium phosphate cement-based material according to claim 1, characterized in that: The concentration of the sodium silicate solution is set to 5%-10%.

5. A method for preparing a water-resistant magnesium phosphate cement-based material according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, collecting wastewater from a phosphoric acid plant and excess sludge from a domestic sewage treatment plant and preparing a composite phosphoric acid compound; Step 2, weighing magnesium oxide, composite phosphate compound, water, borax, sodium silicate solution, polyethylene glycol derivatives, polyacrylamide, and ammonium sulfate solution according to the ratio and mixing them; Step 3, before carrying out step 2, firstly mix the polyacrylamide and the polyethylene glycol derivative with water; Step 4, while carrying out step 2, adding the ammonium sulfate solution to the mixture in batches; Step 5: During step 4, the mixture is stirred.

6. The method for preparing a water-resistant magnesium phosphate cement-based material according to claim 5, characterized in that: The specific preparation process of the composite phosphate compound in step 1 is as follows: Step 11, collecting wastewater from a phosphoric acid plant and excess sludge from a domestic sewage treatment plant, mixing them in equal mass ratios to obtain a mixture, charging the mixture into a reactor, heating the mixture to 70-80° C., and stirring the reaction for 12 hours; Step 12, after the reaction is completed, filter and separate to obtain a filtrate, add sodium sulfide solution dropwise to the filtrate until no more precipitate is generated in the filtrate, filter and remove the precipitate to obtain a secondary filtrate; Step 13, adding calcium hydroxide powder to the secondary filtrate, wherein the mass ratio of the secondary filtrate to calcium hydroxide is 5:1, and stirring the reaction for 10-15 minutes to obtain a mixed suspension; Step 14: add anhydrous ethanol to the mixed suspension, and the mass ratio of the mixed suspension to the anhydrous ethanol is 1:2, continue stirring and reacting for 1-2 hours, and filter to obtain a filter cake, which is the composite phosphate compound.

7. The method for preparing a water-resistant magnesium phosphate cement-based material according to claim 5, characterized in that: The specific preparation process of mixing polyacrylamide and polyethylene glycol derivatives with water in step 3 is as follows: Step 31, injecting clean water in the required mass fraction into the reaction kettle according to the proportion and continuously stirring the clean water; Step 32: While stirring, slowly and dispersedly sprinkle polyacrylamide into the reaction kettle, and continue stirring for a period of time until the polyacrylamide particles are completely dissolved to form a uniform, transparent, viscous solution; Step 33: After the polyacrylamide is completely dissolved, continue stirring and slowly add the polyethylene glycol derivative to evenly disperse it in the water until a uniformly mixed solution is formed.

8. The method for preparing a water-resistant magnesium phosphate cement-based material according to claim 5, characterized in that: In step 4, the ammonium sulfate solution is added to the mixture by dripping or spraying to avoid excessive local concentration.

9. The method for preparing a water-resistant magnesium phosphate cement-based material according to claim 8, characterized in that: During the process of adding the ammonium sulfate solution to the mixture in step 4, the temperature of the mixture is controlled to 20-40° C. by an electric heater, and the temperature of the mixture is gradually increased.

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