A method for preparing low-ablation refractory concrete

Abstract

The invention provides a preparation method of low-ablation refractory concrete, belonging to the technical field of concrete; the preparation method comprises the steps of preparing functionalized alumina, preparing zirconium dioxide sol, compounding and mixing; the step of preparing the zirconium dioxide sol comprises the following steps: adding a zirconium n-butoxide solution to deionized water, stirring evenly, adding a nitric acid solution at a controllable addition rate of 1.3-1.7 mL / min, stirring after the addition is completed, controlling the stirring rate to 535-547 rpm until the solution becomes clear and transparent, adding polyethylene glycol 200 and L-sorbitol, and performing ultrasonic treatment, wherein the ultrasonic time is 8-12 min, the ultrasonic power is 136-143 W, and the ultrasonic frequency is 28-32 kHz. After the ultrasonic treatment is completed, the zirconium dioxide sol is prepared; the refractory concrete prepared by the method of the invention has low ablation rate, good fire resistance, good low-temperature resistance, and high strength.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete, and particularly relates to a method for preparing low-ablation refractory concrete. Background Art

[0002] Low-corrosion refractory concrete is a concrete material with low ablation rate and heat resistance. It can maintain high compressive strength and durability at high temperatures and is widely used in buildings, subways, bridges and other structures.

[0003] The components of low-corrosion refractory concrete mainly include cement, coarse and fine aggregates, water, admixtures and additives; among them, cement is the main cementitious material in concrete, which can provide good bonding properties and mechanical strength; coarse and fine aggregates are the main solid components, which can provide mechanical strength and durability; admixtures and additives are mainly used to improve the heat resistance, corrosion resistance, frost resistance and other properties of concrete.

[0004] Chinese invention patent application CN114380580A discloses a corundum-based low-ablation-rate heat-resistant concrete and its preparation method and application. Specifically, the heat-resistant concrete comprises composite corundum, alumina powder, and pure calcium aluminate cement. The composite corundum is composed of microporous corundum and titanium corundum.

[0005] The heat-resistant concrete produced by this patent has good ablation resistance and high compressive strength, but the refractory concrete produced by this patent has poor frost resistance and its strength performance drops sharply in low temperature environment, which limits its scope of use. Summary of the Invention

[0006] In view of the technical problems existing in the prior art, the present invention provides a method for preparing low-ablation refractory concrete, which has good fire resistance, good ablation resistance and good frost resistance.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for preparing low-ablation refractory concrete includes the steps of preparing functionalized alumina, preparing zirconium dioxide sol, compounding, and mixing. The specific operations are as follows:

[0009] 1. Preparation of functionalized alumina

[0010] (1) Vinylation

[0011] The α-alumina is immersed in a nitric acid solution at a temperature of 53-57° C. for a time of 37-43 minutes. After the immersion, the solution is washed and dried to obtain acid-leached alumina. The acid-leached alumina is placed in an ethanol solution, and then oleamidopropyl betaine is added. After stirring, a vinyl silane coupling agent A173 is added. The temperature is raised to 70-73° C. and stirred for reaction for 4.8-5.2 hours. After the reaction is completed, the temperature is naturally lowered to room temperature, filtered and washed, and dried at 78-82° C. for 23-25 ​​hours to obtain vinyl alumina.

[0012] The particle size of the α-alumina is 130-150 nm;

[0013] The mass concentration of the nitric acid solution is 30-34%;

[0014] The mass ratio of the α-alumina and nitric acid solution is 8.3-8.7:53-60;

[0015] The mass ratio of the acid-leached aluminum oxide, the ethanol solution, the oleamidopropyl betaine, and the vinyl silane coupling agent A173 is 7.3-7.7:92-96:1.2-1.4:0.8-1.2.

[0016] (2) Amination

[0017] The ethylene-containing alumina was placed in tetrahydrofuran, 3-mercapto-1-propylamine was added, and the temperature was raised to 65-69°C at a rate of 0.8-1.2°C / min, and the reaction was stirred for 23-25 ​​hours at a stirring speed of 104-115 rpm. After the stirring reaction was completed, the mixture was naturally cooled to room temperature, washed, and dried to obtain functionalized alumina.

[0018] The mass ratio of the ethylene aluminum oxide, tetrahydrofuran, and 3-mercapto-1-propylamine is 5.4-5.8:107-114:5.3-5.5.

[0019] 2. Preparation of Zirconium Dioxide Sol

[0020] The zirconium n-butoxide solution was added to deionized water and stirred evenly, and then the nitric acid solution was added at a rate of 1.3-1.7 mL / min. After the addition was completed, the mixture was stirred at a rate of 535-547 rpm until the solution became clear and transparent. Polyethylene glycol 200 and L-sorbitol were added, and ultrasonic treatment was performed. The ultrasonic time was 8-12 min, the ultrasonic power was 136-143 W, and the ultrasonic frequency was 28-32 kHz. After the ultrasonic treatment, a zirconium dioxide sol was obtained;

[0021] The mass concentration of the zirconium n-butoxide solution is 82-86%;

[0022] The mass concentration of the nitric acid solution is 65-68%;

[0023] The mass volume ratio of the zirconium n-butoxide solution, deionized water, nitric acid solution, polyethylene glycol 200, and 0.8-1.2 g L-sorbitol is 74-80 mL: 1000 mL: 16-20 mL: 1.2-1.4 g: 0.8-1.2 g.

[0024] 3. Compound

[0025] The functionalized alumina was added to the zirconium dioxide sol, and sodium dodecylbenzenesulfonate was added and stirred at a stirring speed of 114-125 rpm, a stirring temperature of 62-64°C, and a stirring time of 23-25 ​​hours. After the stirring was completed, the mixture was filtered and washed, and finally freeze-dried at -42 to -37°C for 18-22 hours to obtain zirconium dioxide-coated alumina.

[0026] The mass volumes of the functionalized alumina, zirconium dioxide gel, and sodium dodecylbenzenesulfonate are 10.1-10.5 g: 69-73 mL: 0.8-1.0 g.

[0027] 4. Mixing

[0028] Mix ceramsite, aluminate cement, fly ash and zirconium dioxide coated alumina, stir evenly, add steel fiber, montmorillonite powder, polycarboxylate water reducer and mixing aid, continue stirring, the stirring time is 3.0-4.0 minutes, the stirring speed is 210-230 rpm, and after the stirring is completed, refractory concrete is obtained;

[0029] The ceramsite has a particle size of 6.0-6.4 mm and a bulk density of 907-914 kg / m 3 ;

[0030] The particle size of the montmorillonite powder is 180-220 nm;

[0031] The steel fiber has a length of 4.3-4.7 mm and a diameter of 0.5-0.7 mm;

[0032] The mass ratio of the ceramsite, aluminate cement, fly ash, zirconium dioxide coated alumina, steel fiber, montmorillonite powder, polycarboxylate water reducer and mixing additive is 98-103:34.2-35.3:72-76:25.5-26.0:10.7-10.7:8.3-8.8:1.8-2.2:18-18.4;

[0033] The mixing auxiliary agent is a mixture of deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine, and the mass ratio of the deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine is 33-37:1.1-1.4:1.3-1.6.

[0034] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0035] 1. In the present invention, alumina is first dispersed and then treated with a vinyl silane coupling agent to graft vinyl groups onto the surface of the alumina. In the amination step, a thiol group is introduced, and 3-mercapto-1-propylamine is grafted onto the surface of the alumina through a thiol-ene click reaction, so that the surface of the alumina is rich in amino groups. In the present invention, zirconium dioxide sol is prepared and then an alcohol reagent is introduced to make the zirconium dioxide sol contain more hydroxyl groups. In the step of compounding zirconium dioxide and alumina, the hydroxyl groups of zirconium dioxide and alumina are bonded in the form of hydrogen bonds, so that the zirconium dioxide is evenly and firmly coated on the surface of the alumina. The coating is tight, the refractory performance is improved, and the ablation rate is reduced. It is evenly mixed with other components, has good stability and good environmental adaptability, and can still maintain good strength after low-temperature freezing.

[0036] 2. The refractory concrete prepared by the method of the present invention has an ablation rate of 0.31-0.34 mm / s.

[0037] 3. The refractory concrete prepared by the method of the present invention has a 7d compressive strength of 56.8-58.2 MPa, a 7d flexural strength of 10.35-10.66 MPa, a 28d compressive strength of 78.5-79.4 MPa, and a 28d flexural strength of 15.62-15.89 MPa.

[0038] 4. The refractory concrete prepared by the method of the present invention was demolded after curing at room temperature for 7 days and then cured for 21 days. It was then calcined at 600°C for 2 hours and then at 960°C for 2 hours. After naturally cooling to room temperature, the compressive strength was measured to be 74.6-76.3 MPa and the 28d flexural strength was 14.68-15.21 MPa.

[0039] 5. The refractory concrete prepared by the method of the present invention was demolded after curing at room temperature for 7 days, and then cured for 21 days. It was then frozen at -28°C for 24 hours and then frozen at -45°C for 24 hours. The above was one cycle. After 5 cycles, it was naturally cooled to room temperature. The measured compressive strength was 73.8-75.6 MPa, and the 28d flexural strength was 14.60-15.05 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0041] In order to more clearly understand the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described.

[0042] Example 1:

[0043] like Figure 1 As shown, the present invention provides a method for preparing low-ablation refractory concrete, which includes the steps of preparing functionalized alumina, preparing zirconium dioxide sol, compounding, and mixing.

[0044] 1. Preparation of functionalized alumina

[0045] (1) Vinylation

[0046] 8.5 g of α-alumina was immersed in 56 g of nitric acid solution at a temperature of 55° C. for 40 min. After the immersion, the solution was washed and dried to obtain acid-leached alumina. 7.5 g of the acid-leached alumina was placed in 94 g of ethanol solution, and then 1.3 g of oleamidopropyl betaine was added. After stirring evenly, 1.0 g of vinyl silane coupling agent A173 was added. The temperature was raised to 71° C. and stirred for 5.0 h. After the reaction was completed, the temperature was naturally lowered to room temperature, filtered, washed, and dried at 80° C. for 24 h to obtain vinyl alumina.

[0047] The particle size of the α-alumina is 140 nm;

[0048] The mass concentration of the nitric acid solution is 32%.

[0049] (2) Amination

[0050] 5.6 g of ethylene alumina was placed in 110 g of tetrahydrofuran, 5.4 g of 3-mercapto-1-propylamine was added, and the temperature was raised to 67 ° C at a rate of 1.0 ° C / min. The reaction was stirred for 24 hours at a stirring speed of 110 rpm. After the stirring reaction was completed, it was naturally cooled to room temperature, washed, and dried to obtain functionalized alumina.

[0051] 2. Preparation of Zirconium Dioxide Sol

[0052] 78 mL of zirconium n-butoxide solution was added to 1000 mL of deionized water and stirred evenly. 18 mL of nitric acid solution was added at a rate of 1.5 mL / min. After the addition was complete, the mixture was stirred at a rate of 540 rpm until the solution became clear. 1.3 g of polyethylene glycol 200 and 1.0 g of L-sorbitol were added and ultrasonicated for 10 min at a power of 140 W and a frequency of 30 kHz. After the ultrasonication, a zirconium dioxide sol was obtained.

[0053] The mass concentration of the zirconium n-butoxide solution is 84%;

[0054] The mass concentration of the nitric acid solution is 66%.

[0055] 3. Compound

[0056] 10.3 g of functionalized alumina was added to 71 mL of zirconium dioxide sol, and 0.9 g of sodium dodecylbenzenesulfonate was added and stirred at a stirring speed of 120 rpm, a stirring temperature of 63 ° C, and a stirring time of 24 h. After the stirring was completed, the mixture was filtered and washed, and finally freeze-dried at -40 ° C for 20 h to obtain zirconium dioxide-coated alumina.

[0057] 4. Mixing

[0058] 101 g of ceramsite, 34.8 g of aluminate cement, 74 g of fly ash and 25.7 g of zirconium dioxide-coated alumina were mixed and stirred evenly. 10.5 g of steel fiber, 8.5 g of montmorillonite powder, 2.0 g of polycarboxylate water-reducing agent and 18.2 g of mixing aid were added and stirred continuously for 3.5 min at a stirring speed of 220 rpm. After the stirring was completed, refractory concrete was obtained.

[0059] The ceramsite has a particle size of 6.2 mm and a bulk density of 910 kg / m 3 ;

[0060] The particle size of the montmorillonite powder is 200 nm;

[0061] The steel fiber has a length of 4.5 mm and a diameter of 0.6 mm;

[0062] The mixing auxiliary agent is a mixture of deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine, and the mass ratio of the deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine is 35:1.3:1.5.

[0063] Example 2:

[0064] 1. Preparation of functionalized alumina

[0065] (1) Vinylation

[0066] 8.3 g of α-alumina was immersed in 53 g of nitric acid solution at a temperature of 53° C. for 37 min. After immersion, the solution was washed and dried to obtain acid-leached alumina. 7.3 g of the acid-leached alumina was placed in 92 g of ethanol solution, and then 1.2 g of oleamidopropyl betaine was added. After stirring evenly, 0.8 g of vinyl silane coupling agent A173 was added. The temperature was raised to 70° C. and stirred for reaction for 4.8 h. After the reaction was completed, the temperature was naturally lowered to room temperature, filtered, washed, and dried at 78° C. for 23 h to obtain vinyl alumina.

[0067] The particle size of the α-alumina is 130 nm;

[0068] The mass concentration of the nitric acid solution is 30%.

[0069] (2) Amination

[0070] 5.4 g of ethylene-containing alumina was placed in 107 g of tetrahydrofuran, 5.3 g of 3-mercapto-1-propylamine was added, and the temperature was raised to 65 ° C at a rate of 0.8 ° C / min, and the reaction was stirred for 23 hours at a stirring speed of 104 rpm. After the stirring reaction was completed, the mixture was naturally cooled to room temperature, washed, and dried to obtain functionalized alumina.

[0071] 2. Preparation of Zirconium Dioxide Sol

[0072] 74 mL of zirconium n-butoxide solution was added to 1000 mL of deionized water and stirred evenly. 16 mL of nitric acid solution was added at a rate of 1.3 mL / min. After the addition was complete, the mixture was stirred at a rate of 535 rpm until the solution became clear. 1.2 g of polyethylene glycol 200 and 0.8 g of L-sorbitol were added and ultrasonic treatment was performed. The ultrasonic treatment time was 8 min, the ultrasonic power was 136 W, and the ultrasonic frequency was 28 kHz. After the ultrasonic treatment, a zirconium dioxide sol was obtained.

[0073] The mass concentration of the zirconium n-butoxide solution is 82%;

[0074] The mass concentration of the nitric acid solution is 65%.

[0075] 3. Compound

[0076] 10.1 g of functionalized alumina was added to 69 mL of zirconium dioxide sol, and 0.8 g of sodium dodecylbenzenesulfonate was added and stirred at a stirring speed of 114 rpm, a stirring temperature of 62 ° C, and a stirring time of 23 h. After the stirring was completed, the mixture was filtered and washed, and finally freeze-dried at -42 ° C for 18 h to obtain zirconium dioxide-coated alumina.

[0077] 4. Mixing

[0078] 98 g of ceramsite, 34.2 g of aluminate cement, 72 g of fly ash and 25.5 g of zirconium dioxide-coated alumina were mixed and stirred evenly. 10.3 g of steel fiber, 8.3 g of montmorillonite powder, 1.8 g of polycarboxylate water-reducing agent and 18.0 g of mixing aid were added and stirred continuously for 3.0 min at a stirring speed of 210 rpm. After the stirring was completed, refractory concrete was obtained.

[0079] The ceramsite has a particle size of 6.0 mm and a bulk density of 907 kg / m 3 ;

[0080] The particle size of the montmorillonite powder is 180 nm;

[0081] The steel fiber has a length of 4.3 mm and a diameter of 0.5 mm;

[0082] The mixing auxiliary agent is a mixture of deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine, and the mass ratio of the deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine is 33:1.1:1.3.

[0083] Example 3:

[0084] 1. Preparation of functionalized alumina

[0085] (1) Vinylation

[0086] 8.7 g of α-alumina was immersed in 60 g of nitric acid solution at a temperature of 57° C. for 43 min. After the immersion, the solution was washed and dried to obtain acid-leached alumina. 7.7 g of the acid-leached alumina was placed in 96 g of ethanol solution, and then 1.4 g of oleamidopropyl betaine was added. After stirring evenly, 1.2 g of vinyl silane coupling agent A173 was added. The temperature was raised to 73° C. and stirred for 5.2 h. After the reaction was completed, the temperature was naturally lowered to room temperature, filtered, washed, and dried at 82° C. for 25 h to obtain vinyl alumina.

[0087] The particle size of the α-alumina is 150 nm;

[0088] The mass concentration of the nitric acid solution is 34%.

[0089] (2) Amination

[0090] 5.8 g of ethylene-containing alumina was placed in 114 g of tetrahydrofuran, 5.5 g of 3-mercapto-1-propylamine was added, and the temperature was raised to 69° C. at a rate of 1.2° C. / min. The reaction was stirred for 25 h at a stirring speed of 115 rpm. After the stirring reaction was completed, the mixture was naturally cooled to room temperature, washed, and dried to obtain functionalized alumina.

[0091] 2. Preparation of Zirconium Dioxide Sol

[0092] 80 mL of zirconium n-butoxide solution was added to 1000 mL of deionized water and stirred evenly. 20 mL of nitric acid solution was added at a rate of 1.7 mL / min. After the addition was complete, the mixture was stirred at a rate of 547 rpm until the solution became clear. 1.4 g of polyethylene glycol 200 and 1.2 g of L-sorbitol were added and ultrasonicated for 12 min at a power of 143 W and a frequency of 32 kHz. After the ultrasonication, a zirconium dioxide sol was obtained.

[0093] The mass concentration of the zirconium n-butoxide solution is 86%;

[0094] The mass concentration of the nitric acid solution is 68%.

[0095] 3. Compound

[0096] 10.5 g of functionalized alumina was added to 73 mL of zirconium dioxide sol, and 1.0 g of sodium dodecylbenzenesulfonate was added and stirred at a stirring speed of 125 rpm, a stirring temperature of 64 ° C, and a stirring time of 25 h. After the stirring was completed, the mixture was filtered and washed, and finally freeze-dried at -37 ° C for 22 h to obtain zirconium dioxide-coated alumina.

[0097] 4. Mixing

[0098] 103 g of ceramsite, 35.3 g of aluminate cement, 76 g of fly ash and 26.0 g of zirconium dioxide-coated alumina were mixed and stirred evenly. 10.7 g of steel fiber, 8.8 g of montmorillonite powder, 2.2 g of polycarboxylate water-reducing agent and 18.4 g of mixing aid were added and stirred continuously for 4.0 min at a stirring speed of 230 rpm. After the stirring was completed, refractory concrete was obtained.

[0099] The ceramsite has a particle size of 6.4 mm and a bulk density of 914 kg / m 3 ;

[0100] The particle size of the montmorillonite powder is 220 nm;

[0101] The steel fiber has a length of 4.7 mm and a diameter of 0.7 mm;

[0102] The mixing auxiliary agent is a mixture of deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine, and the mass ratio of the deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine is 37:1.4:1.6.

[0103] Comparative Example 1:

[0104] On the basis of Example 1, the changes are as follows:

[0105] The step of preparing functionalized alumina is omitted; the step of preparing zirconium dioxide sol is omitted;

[0106] The compounding step is to mix 10.3g of α-alumina and 10.3g of zirconium dioxide powder, and mix them evenly to obtain zirconium dioxide-coated alumina;

[0107] The particle size of the α-alumina powder is 140 nm; the particle size of the zirconium dioxide powder is 120 nm;

[0108] The rest of the operations are the same.

[0109] Comparative Example 2:

[0110] On the basis of Example 1, the changes are as follows:

[0111] (1) The step of preparing the functionalized alumina is to soak 8.5 g of α-alumina in 56 g of nitric acid solution at a soaking temperature of 55° C. for 40 min. After the soaking, washing and drying are performed to obtain acid-leached alumina, which is the functionalized alumina.

[0112] The particle size of the α-alumina is 140 nm;

[0113] The mass concentration of the nitric acid solution is 32%.

[0114] (2) The step of preparing the zirconium dioxide sol is as follows: adding 78 mL of zirconium n-butoxide solution to 1000 mL of deionized water, stirring evenly, adding 18 mL of nitric acid solution, controlling the addition rate to be 1.5 mL / min, and stirring after the addition is completed, controlling the stirring rate to be 540 rpm until the solution becomes clear and transparent, thereby preparing the zirconium dioxide sol;

[0115] The rest of the operations are the same.

[0116] Performance testing:

[0117] The refractory concretes prepared in Examples 1-3 and Comparative Examples 1-2 were vibrated and molded in 150×150×150 mm molds, cured at room temperature for 7 days, demolded, and tested for strength. After further curing for 21 days, test specimens were prepared and tested for ablation rate, fire resistance, and low-temperature resistance.

[0118] The fire resistance test method is as follows: the test samples prepared in Examples 1-3 and Comparative Examples 1-2 are calcined at 600°C for 2 hours, then calcined at 960°C for 2 hours, and then cooled to room temperature, and then the strength performance is tested again.

[0119] The method for testing the low-temperature resistance is to freeze the samples to be tested prepared in Examples 1-3 and Comparative Examples 1-2 at -28°C for 24 hours, and then freeze them at -45°C for 24 hours. The above is one cycle. After 5 cycles, the samples are naturally cooled to room temperature and the strength performance is tested again.

[0120] The test results are as follows:

[0121] Table 1 Test data of Examples and Comparative Examples

[0122]

[0123] The present invention first performs a dispersion treatment on alumina, and then uses a vinyl silane coupling agent to treat it, so that vinyl groups are grafted onto the surface of the alumina. In the amination step, a mercapto group is introduced, and 3-mercapto-1-propylamine is grafted onto the surface of the alumina through a mercapto-ene click reaction, so that the surface of the alumina is rich in amino groups. The present invention prepares a zirconium dioxide sol, and then introduces an alcohol reagent, so that the zirconium dioxide sol contains more hydroxyl groups. In the step of compounding zirconium dioxide and alumina, the hydroxyl groups of the zirconium dioxide and the alumina are combined in the form of hydrogen bonds, so that the zirconium dioxide is evenly and firmly coated on the surface of the alumina, the coating is tight, the fire resistance is improved, the ablation rate is reduced, the zirconium dioxide is evenly mixed with other components, the stability is good, the environmental adaptability is good, and the strength can still be maintained after low-temperature freezing.

[0124] In Comparative Example 1, α-alumina and zirconium dioxide powders were directly mixed, resulting in strong agglomeration and poor dispersion. The two powders could not be evenly dispersed, which resulted in poor homogeneity and strength of the concrete, and further resulted in poor fire resistance and low temperature resistance, and a high ablation rate.

[0125] In Comparative Example 2, the surface of alumina was treated to increase the roughness of the surface of alumina, and then the alumina was placed in a zirconium dioxide sol for coating. The bonding strength between the alumina and the zirconium dioxide was poor, and the coating was uneven and not firm. The concrete produced had low strength and poor stability.

[0126] Unless otherwise specified, all ratios and percentages described in the present invention are by mass.

[0127] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing low-ablation refractory concrete, characterized in that: The preparation method includes the steps of preparing functionalized alumina, preparing zirconium dioxide sol, compounding and mixing; The preparation of functionalized alumina includes vinylation and amination steps; The vinylation step comprises: placing α-alumina in a nitric acid solution for soaking at a temperature of 53-57° C. for 37-43 minutes, washing and drying after soaking to obtain acid-leached alumina; placing the acid-leached alumina in an ethanol solution, then adding oleamidopropyl betaine, stirring evenly, adding vinyl silane coupling agent A173, raising the temperature to 70-73° C., stirring and reacting for 4.8-5.2 hours, and naturally cooling to room temperature after the reaction is completed, filtering and washing, and drying at 78-82° C. for 23-25 ​​hours to obtain vinylated alumina; The amination step comprises placing ethylene-containing aluminum oxide in tetrahydrofuran, adding 3-mercapto-1-propylamine, heating to 65-69° C. at a rate of 0.8-1.2° C. / min, stirring and reacting for 23-25 ​​hours at a stirring speed of 104-115 rpm. After the stirring reaction is completed, the mixture is naturally cooled to room temperature, washed, and dried to obtain functionalized aluminum oxide. The steps of preparing the zirconium dioxide sol are as follows: adding a zirconium n-butoxide solution to deionized water, stirring evenly, adding a nitric acid solution at a rate of 1.3-1.7 mL / min, stirring after the addition is complete, controlling the stirring rate to 535-547 rpm until the solution is clear and transparent, adding polyethylene glycol 200 and L-sorbitol, and performing ultrasonic treatment, wherein the ultrasonic time is 8-12 minutes, the ultrasonic power is 136-143 W, and the ultrasonic frequency is 28-32 kHz. After the ultrasonic treatment is completed, the zirconium dioxide sol is obtained; The compounding step comprises adding the functionalized alumina to the zirconium dioxide sol, adding sodium dodecylbenzenesulfonate and stirring at a stirring speed of 114-125 rpm, a stirring temperature of 62-64° C., and a stirring time of 23-25 ​​hours. After the stirring is completed, filtering and washing are performed, and finally freeze-drying is performed at -42 to -37° C. for 18-22 hours to obtain the zirconium dioxide-coated alumina. The mixing step comprises mixing ceramsite, aluminate cement, fly ash and zirconium dioxide-coated alumina, stirring evenly, adding steel fiber, montmorillonite powder, polycarboxylate water reducer and mixing aid, and continuing stirring for 3.0-4.0 minutes at a stirring speed of 210-230 rpm to obtain refractory concrete. The mixing aid is a mixture of deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine, and the mass ratio of the deionized water, polyvinyl pyrrolidone and cocoyl diethanolamine is 33-37: 1.1-1.4:1.3-1.6。 2. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: In the vinylation step, the particle size of the α-alumina is 130-150 nm. The mass concentration of the nitric acid solution is 30-34%, The mass ratio of the α-alumina and the nitric acid solution is 8.3-8.7:53-60.

3. The method for preparing low-ablation refractory concrete according to claim 2, characterized in that: The mass ratio of the acid-leached aluminum oxide, the ethanol solution, the oleamidopropyl betaine, and the vinyl silane coupling agent A173 is 7.3-7.7:92-96:1.2-1.4:0.8-1.

2.

4. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: In the amination step, the mass ratio of the ethylene aluminum oxide, tetrahydrofuran, and 3-mercapto-1-propylamine is 5.4-5.8:107-114:5.3-5.

5.

5. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: In the step of preparing the zirconium dioxide sol, the mass concentration of the zirconium n-butoxide solution is 82-86%, The mass concentration of the nitric acid solution is 65-68%, The mass volume ratio of the zirconium n-butoxide solution, deionized water, nitric acid solution, polyethylene glycol 200, and L-sorbitol is 74-80 mL: 1000 mL: 16-20 mL: 1.2-1.4 g: 0.8-1.2 g.

6. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: In the compounding step, the mass volumes of the functionalized alumina, zirconium dioxide sol, and sodium dodecylbenzenesulfonate are 10.1-10.5 g: 69-73 mL: 0.8-1.0 g.

7. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: The ceramsite has a particle size of 6.0-6.4 mm and a bulk density of 907-914 kg / m 3 ; The particle size of the montmorillonite powder is 180-220 nm; The steel fiber has a length of 4.3-4.7 mm and a diameter of 0.5-0.7 mm.

8. The method for preparing low-ablation refractory concrete according to claim 1, characterized in that: The mass ratios of the ceramsite, aluminate cement, fly ash, zirconium dioxide-coated alumina, steel fiber, montmorillonite powder, polycarboxylate water reducer and mixing additive are 98-103:34.2-35.3:72-76:25.5-26.0:10.7-10.7:8.3-8.8:1.8-2.2:18-18.4.

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