High-strength, crack-resistant and corrosion-resistant castable and preparation method thereof

Abstract

This application belongs to the field of refractory castable technology, specifically providing a high-strength, crack-resistant, and corrosion-resistant castable and its preparation method. A high-strength, crack-resistant, and corrosion-resistant castable comprises the following components: dense corundum, brown corundum, white corundum, bauxite, silicon carbide, activated alumina, spherical asphalt, pure calcium aluminate cement, sodium hexametaphosphate, antioxidant, and composite additives; the composite additives are prepared by combining layered bimetallic hydroxides with modified MOF. The high-strength, crack-resistant, and corrosion-resistant castable prepared by this application exhibits good high-temperature flexural strength and corrosion resistance.

Description

Technical Field

[0001] This application belongs to the field of refractory castable technology, and in particular relates to a high-strength, crack-resistant, and corrosion-resistant castable and its preparation method. Background Technology

[0002] Blast furnace ironmaking is the primary ironmaking process, and the blast furnace tapping trough is a crucial component of the blast furnace ironmaking system. Refractory castables are important lining materials. With the increasing size, lifespan, and high-temperature, high-pressure operation of modern blast furnaces, the temperature of molten iron has increased, the tapping volume has increased, the tapping time has lengthened, and the molten iron flow rate has increased, making the application conditions of the trough lining materials more demanding. Al2O3-SiC-C (ASC) castable is an unshaped refractory material made primarily of Al2O3, SiC, and C, with the addition of other additives. It possesses excellent thermal shock resistance and slag erosion resistance and is widely used in blast furnace tapping troughs and other parts. ASC castables often use pure calcium aluminate cement as a binder. However, the CaO in the cement binder easily reacts with Al2O3 and SiO2 at high temperatures to form a low-melting-point phase, thereby reducing the material's high-temperature strength and erosion resistance, thus limiting its application range.

[0003] To address the above issues, patent application CN107353018A discloses a castable refractory for iron hooks. This application utilizes a composite admixture composed of citric acid aqueous solution, chemically pure trisodium phosphate solution, and calcium lignosulfonate solution. The addition of phosphate forms non-floating phosphate on the surface of the clinker phase, reducing the number of open pores and increasing the number of closed pores, thereby improving impermeability. Lignosulfonate has semi-colloidal properties, which can form a film-like cementitious layer between cement hydration products, mutually filling the hydration products and increasing density, thus improving the strength of the castable refractory.

[0004] The above document states that by adding composite admixtures, cement hydration is hindered to some extent, making cement hydration more orderly and the structure formed by hydration more compact. However, it does not directly solve the problem that the CaO introduced by the cement binder forms a low-melting-point phase with the other components in the matrix, thereby reducing the strength and corrosion resistance of the castable. Summary of the Invention

[0005] To address the aforementioned problems and further improve the strength and corrosion resistance of high-strength crack-resistant and corrosion-resistant castables, this application provides a high-strength crack-resistant and corrosion-resistant castable and its preparation method.

[0006] This application first provides a high-strength, crack-resistant, and corrosion-resistant castable, comprising the following components by weight: 11-13 parts dense corundum, 21-23 parts brown corundum, 13-15 parts white corundum, 20-22 parts bauxite, 13-15 parts silicon carbide, 7-9 parts activated alumina, 1-2.5 parts spherical asphalt, 4-6 parts pure calcium aluminate cement, 0.1-0.3 parts sodium hexametaphosphate, 1-2 parts antioxidant, and 5-7 parts composite additives;

[0007] The composite additive is prepared by combining a layered bimetallic hydroxide with a modified MOF.

[0008] Furthermore, the preparation method of the composite additive includes the following steps: A1, ultrasonically dispersing the modified MOF in deionized water to obtain a modified MOF suspension; A2, dissolving MgCl2·6H2O and Al(NO3)3·9H2O in distilled water to obtain a layered bimetallic hydroxide precursor; dissolving ammonium dihydrogen phosphate and NaOH in distilled water to obtain solution 1; A3, slowly adding the layered bimetallic hydroxide precursor to the modified MOF suspension, stirring vigorously for 1 hour, then adding solution 1, aging, filtration, washing, and drying to obtain the final product.

[0009] Furthermore, in A3, the mass ratio of the layered bimetallic hydroxide precursor to the modified MOF is 3-4.5:1.

[0010] Furthermore, the preparation method of the modified MOF includes the following steps: 1) dissolving zirconium tetrachloride in DMF to obtain solution A; adding a monocarboxylic acid to DMF, dissolving it, then adding terephthalic acid, stirring and dissolving to obtain solution B; 2) ultrasonically mixing solution A and solution B, reacting, washing and drying to obtain a monocarboxylic acid modified MOF; 3) adding the monocarboxylic acid modified MOF to cerium nitrate solution, calcining it to obtain the modified MOF.

[0011] Furthermore, in 1), the monocarboxylic acid is octanoic acid or butyric acid.

[0012] Furthermore, in step 2), the molar ratio of zirconium tetrachloride to terephthalic acid to monocarboxylic acid in solutions A and B is 1:0.5-1:20-25.

[0013] Furthermore, in step 3), the mass ratio of the monocarboxylic acid-modified MOF to cerium nitrate hexahydrate is 1:3-5.

[0014] Furthermore, the dense corundum is composed of a mixture of dense corundum with a particle size of 5-8 mm and dense corundum with a particle size of 3-5 mm; the brown corundum is composed of a mixture of brown corundum with a particle size of 1-3 mm and brown corundum with a particle size of 0-1 mm; the white corundum has a particle size of 325 mesh; the bauxite is composed of a mixture of bauxite with a particle size of 3-5 mm and bauxite with a particle size of 1-3 mm; and the silicon carbide is composed of a mixture of silicon carbide with a particle size of 1-3 mm and silicon carbide with a particle size of 325 mesh.

[0015] Furthermore, this application provides a method for preparing a high-strength, crack-resistant, and corrosion-resistant castable, comprising the following steps: S1, weighing each raw material according to the proportion, dry mixing, adding deionized water, and then wet mixing to obtain a mixed slurry; S2, injecting the mixed slurry into a mold, vibrating to form it, curing it in the mold, and then demolding it to obtain a billet; S3, drying the billet and then calcining it at high temperature to obtain the final product.

[0016] Furthermore, the high-temperature calcination involves heating to 1000℃-1100℃ at a rate of 3℃ / min, holding at that temperature for 3 hours, and then heating to 1400℃-1500℃ at a rate of 5℃ / min, holding at that temperature for 3 hours.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] 1. In the composite additive, the modified MOF constructs a defect structure through monocarboxylic acid modification. The resulting unsaturated Zr sites can enhance coordination with phosphate, allowing the layered bimetallic hydroxides intercalated with phosphate to adhere to the surface of the modified MOF, thereby enhancing the bonding force between the two.

[0019] 2. During the hydration and heat treatment of the castable, CeO2 in the modified MOF can react with CaO to form a high-melting-point calcium-cerium composite oxide, which can reduce free CaO. After calcination, the layered bimetallic hydroxide forms a magnesium-aluminum composite oxide, which reacts with calcium oxide and, together with ZrO2 formed after calcination of the modified MOF, promotes sintering and densification, reduces the formation of low-melting-point phases, and enhances the bonding between the castable aggregate and the matrix, thereby enhancing the high-temperature flexural strength of the castable. In addition, ZrO2 is uniformly dispersed in the castable matrix, which can promote the nucleation and growth of CA6 grains, increase the amount of plate-like CA6, and its staggered distribution in the matrix can bear the load and effectively hinder crack propagation. At the same time, the high melting point of ZrO2 will increase the volume fraction of finely dispersed solid particles in the slag during slag erosion, increase the viscosity of the slag, reduce the penetration of the slag into the castable, and thus enhance the castable's resistance to slag erosion. Attached Figure Description

[0020] Figure 1 This is a SEM image of the composite additive in Example 2.

[0021] Figure 2The diagrams show the room temperature compressive strength of Examples 1-3 and Comparative Examples 1-2.

[0022] Figure 3 The diagrams show the room temperature flexural strength of Examples 1-3 and Comparative Examples 1-2.

[0023] Figure 4 The image shows the XRD pattern of the modified MOF in Example 2. Detailed Implementation

[0024] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. Obviously, the described embodiments are only a portion of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only” is used, in which case another component may be added.

[0027] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0028] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0029] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0030] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0031] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0032] Example 1

[0033] The high-strength, crack-resistant, and corrosion-resistant castable in this embodiment comprises the following components by weight: 1.1 kg dense corundum (composed of 0.5 kg of dense corundum with a particle size of 5-8 mm and 0.6 kg of dense corundum with a particle size of 3-5 mm), 2.1 kg brown corundum (composed of 1.1 kg of brown corundum with a particle size of 1-3 mm and 1 kg of brown corundum with a particle size of 0-1 mm), 1.3 kg white corundum with a particle size of 325 mesh, 2 kg bauxite (composed of 1.2 kg of bauxite with a particle size of 3-5 mm and 0.8 kg of bauxite with a particle size of 1-3 mm), 1.3 kg silicon carbide (composed of 0.7 kg of silicon carbide with a particle size of 1-3 mm and 0.6 kg of silicon carbide with a particle size of 325 mesh), 0.7 kg activated alumina, 0.1 kg spherical asphalt, 0.4 kg pure calcium aluminate cement, 10 g sodium hexametaphosphate, 0.1 kg antioxidant, and 0.5 kg composite additives.

[0034] The preparation method of the high-strength, crack-resistant, and corrosion-resistant castable in this embodiment is as follows:

[0035] S1, weigh out dense corundum, brown corundum, white corundum, bauxite, silicon carbide, activated alumina, spherical asphalt, pure calcium aluminate cement, sodium hexametaphosphate, antioxidant and composite additives, dry mix for 60s, then add 0.6kg of deionized water and wet mix for 180s to obtain a mixed slurry.

[0036] S2. The mixed slurry is injected into the mold, vibrated to form the shape, and cured in the mold at 25°C for 48 hours before demolding to obtain the blank.

[0037] S3. The billet is dried at 110℃ for 24 hours, then heated to 1000℃ at a rate of 3℃ / min and held for 3 hours in air, then heated to 1400℃ at a rate of 5℃ / min and held for 3 hours, and then cooled to room temperature to obtain high-strength crack-resistant and corrosion-resistant castable.

[0038] The preparation method of the composite additive in this embodiment is as follows:

[0039] A1. 2g of modified MOF was ultrasonically dispersed in deionized water to prepare a modified MOF suspension.

[0040] A2, 3.66g MgCl2·6H2O and 2.25g Al(NO3)3·9H2O were poured into a beaker, and 60mL of distilled water was added to prepare a layered bimetallic hydroxide precursor; 0.35g ammonium dihydrogen phosphate and 2.16g NaOH were poured into a beaker, and 30mL of distilled water was added and stirred to prepare solution 1.

[0041] A3. The layered bimetallic hydroxide precursor was slowly added dropwise to the modified MOF suspension and stirred vigorously for 1 hour. Then, while stirring, solution 1 was slowly added dropwise at a rate of 0.5 mL / min to maintain the pH at 8-9. The mixture was stirred for 30 minutes and aged at 60°C for 10 hours. After aging, the mixture was filtered, washed with distilled water until the pH reached 7, and then dried at 100°C for 6 hours to obtain the composite additive.

[0042] The modified MOF in this embodiment is prepared as follows:

[0043] 1) Dissolve 0.93 g of zirconium tetrachloride (4 mmol) in 15 mL of DMF, heat to 80 °C, and maintain for 30 min to obtain solution A; add 7 g of butyric acid (80 mmol) to 15 mL of DMF solution, heat to 80 °C, maintain for 30 min, then add 0.4 g of terephthalic acid (2.4 mmol), heat to 80 °C, and maintain for 30 min to obtain solution B;

[0044] 2) Mix solutions A and B under ultrasonic treatment for 10 min to obtain a mixed solution; transfer the mixed solution to a high-pressure vessel lined with polytetrafluoroethylene and react at 120℃ for 24 h. After the reaction is completed, cool to room temperature, collect the precipitate by centrifugation, and wash with DMF. Place the product in 80 mL of mixed solution (1.25% hydrochloric acid and 98.75% DMF) and react at 90℃ for 12 h. Repeat this step 3 times. Collect the product by centrifugation, wash with DMF and methanol in sequence, and then soak in methanol twice for solvent exchange, 24 h each time. Finally, vacuum dry at 75℃ for 12 h to obtain butyric acid modified MOF.

[0045] 3) Add 6g of cerium nitrate hexahydrate to 100ml of deionized water and stir with a glass rod until the solid is completely dissolved to obtain a cerium nitrate hexahydrate solution; add 2g of butyric acid-modified MOF to the cerium nitrate hexahydrate solution, sonicate for 30min and let stand for 12h; filter, dry at 105℃ for 24h and then calcine in a muffle furnace at a calcination temperature of 250℃ (heating rate 5℃ / min) for 3h, and then cool naturally to room temperature to obtain the modified MOF.

[0046] Example 2

[0047] The high-strength, crack-resistant, and corrosion-resistant castable in this embodiment comprises the following components by weight: 1.2 kg dense corundum (composed of 0.6 kg of dense corundum with a particle size of 5-8 mm and 0.6 kg of dense corundum with a particle size of 3-5 mm), 2.2 kg brown corundum (composed of 1.2 kg of brown corundum with a particle size of 1-3 mm and 1 kg of brown corundum with a particle size of 0-1 mm), 1.4 kg white corundum with a particle size of 325 mesh, 2.1 kg bauxite (composed of 1.2 kg of bauxite with a particle size of 3-5 mm and 0.9 kg of bauxite with a particle size of 1-3 mm), 1.4 kg silicon carbide (composed of 0.7 kg of silicon carbide with a particle size of 1-3 mm and 0.7 kg of silicon carbide with a particle size of 325 mesh), 0.8 kg activated alumina, 0.15 kg spherical asphalt, 0.5 kg pure calcium aluminate cement, 20 g sodium hexametaphosphate, 0.2 kg antioxidant, and 0.6 kg composite additives.

[0048] The preparation method of the high-strength, crack-resistant, and corrosion-resistant castable in this embodiment is as follows:

[0049] S1, weigh out dense corundum, brown corundum, white corundum, bauxite, silicon carbide, activated alumina, spherical asphalt, pure calcium aluminate cement, sodium hexametaphosphate, antioxidant and composite additives, dry mix for 60s, then add 0.7kg of deionized water and wet mix for 180s to obtain a mixed slurry.

[0050] S2. The mixed slurry is injected into the mold, vibrated to form the shape, and cured in the mold at 25°C for 48 hours before demolding to obtain the blank.

[0051] S3. The billet is dried at 110℃ for 24 hours, then heated to 1100℃ at a rate of 3℃ / min and held for 3 hours in air, then heated to 1450℃ at a rate of 5℃ / min and held for 3 hours, and then cooled to room temperature to obtain high-strength crack-resistant and corrosion-resistant castable.

[0052] The preparation method of the composite additive in this embodiment is as follows:

[0053] A1. 2g of modified MOF was ultrasonically dispersed in deionized water to prepare a modified MOF suspension.

[0054] A2, 4.88g MgCl2·6H2O and 3g Al(NO3)3·9H2O were poured into a beaker, and 60mL of distilled water was added to prepare a layered bimetallic hydroxide precursor. 0.46g ammonium dihydrogen phosphate and 2.56g NaOH were poured into a beaker, and 30mL of distilled water was added and stirred to prepare solution 1.

[0055] A3. The layered bimetallic hydroxide precursor was slowly added dropwise to the modified MOF suspension and stirred vigorously for 1 hour. Then, while stirring, solution 1 was slowly added dropwise at a rate of 0.5 mL / min to maintain the pH at 8-9. The mixture was stirred for 30 minutes and aged at 60°C for 10 hours. After aging, the mixture was filtered, washed with distilled water until the pH reached 7, and then dried at 100°C for 6 hours to obtain the composite additive.

[0056] The modified MOF in this embodiment is prepared as follows:

[0057] 1) Dissolve 0.93 g zirconium tetrachloride (4 mmol) in 15 mL DMF, heat to 80 °C, and maintain for 30 min to obtain solution A; add 14.4 g octanoic acid (100 mmol) to 20 mL DMF solution, heat to 80 °C, maintain for 30 min, then add 0.33 g terephthalic acid (2 mmol), heat to 80 °C, and maintain for 30 min to obtain solution B;

[0058] 2) Mix solutions A and B under ultrasonic treatment for 10 min to obtain a mixed solution; transfer the mixed solution to a high-pressure vessel lined with polytetrafluoroethylene and react at 120℃ for 24 h. After the reaction is completed, cool to room temperature, collect the precipitate by centrifugation, and wash with DMF. Place the product in 80 mL of mixed solution (1.25% hydrochloric acid and 98.75% DMF) and react at 90℃ for 12 h. Repeat this step 3 times. Collect the product by centrifugation, wash with DMF and methanol in sequence, and then soak in methanol twice for solvent exchange, 24 h each time. Finally, vacuum dry at 75℃ for 12 h to obtain octanoic acid modified MOF.

[0059] 3) Add 9.24g of cerium nitrate hexahydrate to 100ml of deionized water and stir with a glass rod until the solid is completely dissolved to obtain a cerium nitrate hexahydrate solution; add 2g of octanoic acid-modified MOF to the cerium nitrate hexahydrate solution, sonicate for 30min and let stand for 12h; filter, dry at 105℃ for 24h and then calcine in a muffle furnace at a calcination temperature of 250℃ (heating rate 5℃ / min) for 3h, and then cool naturally to room temperature to obtain the modified MOF.

[0060] Example 3

[0061] The high-strength, crack-resistant, and corrosion-resistant castable in this embodiment comprises the following components by weight: 1.3 kg dense corundum (composed of 0.6 kg of dense corundum with a particle size of 5-8 mm and 0.7 kg of dense corundum with a particle size of 3-5 mm), 2.3 kg brown corundum (composed of 1.2 kg of brown corundum with a particle size of 1-3 mm and 1.1 kg of brown corundum with a particle size of 0-1 mm), 1.5 kg white corundum with a particle size of 325 mesh, 2.2 kg bauxite (composed of 1.2 kg of bauxite with a particle size of 3-5 mm and 1 kg of bauxite with a particle size of 1-3 mm), 1.5 kg silicon carbide (composed of 0.8 kg of silicon carbide with a particle size of 1-3 mm and 0.7 kg of silicon carbide with a particle size of 325 mesh), 0.9 kg activated alumina, 0.2 kg spherical asphalt, 0.6 kg pure calcium aluminate cement, 30 g sodium hexametaphosphate, 0.15 kg antioxidant, and 0.7 kg composite additives.

[0062] The preparation method of the high-strength, crack-resistant, and corrosion-resistant castable in this embodiment is as follows:

[0063] S1, weigh out dense corundum, brown corundum, white corundum, bauxite, silicon carbide, activated alumina, spherical asphalt, pure calcium aluminate cement, sodium hexametaphosphate, antioxidant and composite additives, dry mix for 60s, then add 0.8kg of deionized water and wet mix for 180s to obtain a mixed slurry.

[0064] S2, the mixed slurry is injected into the mold, vibrated to form, and cured in the mold at 25°C for 48 hours before demolding to obtain the blank.

[0065] S3. The billet is dried at 110℃ for 24 hours, then heated to 1100℃ at a rate of 3℃ / min and held for 3 hours in air, then heated to 1500℃ at a rate of 5℃ / min and held for 3 hours, and then cooled to room temperature to obtain high-strength crack-resistant and corrosion-resistant castable.

[0066] The preparation method of the composite additive in this embodiment is as follows:

[0067] A1. 2g of modified MOF was ultrasonically dispersed in deionized water to prepare a modified MOF suspension.

[0068] A2, 5.57g MgCl2·6H2O and 3.43g Al(NO3)3·9H2O were poured into a beaker, and 60mL of distilled water was added to prepare a layered bimetallic hydroxide precursor. 0.53g ammonium dihydrogen phosphate and 3.22g NaOH were poured into a beaker, and 30mL of distilled water was added and stirred to prepare solution 1.

[0069] A3. The layered bimetallic hydroxide precursor was slowly added dropwise to the modified MOF suspension and stirred vigorously for 1 hour. Then, while stirring, solution 1 was slowly added dropwise at a rate of 0.5 mL / min to maintain the pH at 8-9. The mixture was stirred for 30 minutes and aged at 60°C for 10 hours. After aging, the mixture was filtered, washed with distilled water until the pH reached 7, and then dried at 100°C for 6 hours to obtain the composite additive.

[0070] The modified MOF in this embodiment is prepared as follows:

[0071] 1) Dissolve 0.93 g zirconium tetrachloride (4 mmol) in 15 mL DMF, heat to 80 °C, and maintain for 30 min to obtain solution A; add 14.4 g octanoic acid (100 mmol) to 20 mL DMF solution, heat to 80 °C, maintain for 30 min, then add 0.66 g terephthalic acid (4 mmol), heat to 80 °C, and maintain for 30 min to obtain solution B;

[0072] 2) Mix solutions A and B under ultrasonic treatment for 10 min to obtain a mixed solution; transfer the mixed solution to a high-pressure vessel lined with polytetrafluoroethylene and react at 120℃ for 24 h. After the reaction is completed, cool to room temperature, collect the precipitate by centrifugation, and wash with DMF. Place the product in 80 mL of mixed solution (1.25% hydrochloric acid and 98.75% DMF) and react at 90℃ for 12 h. Repeat this step 3 times. Collect the product by centrifugation, wash with DMF and methanol in sequence, and then soak in methanol twice for solvent exchange, 24 h each time. Finally, vacuum dry at 75℃ for 12 h to obtain octanoic acid modified MOF.

[0073] 3) Add 7.5g of cerium nitrate hexahydrate to 100ml of deionized water and stir with a glass rod until the solid is completely dissolved to obtain a cerium nitrate hexahydrate solution; add 2g of octanoic acid-modified MOF to the cerium nitrate hexahydrate solution, sonicate for 30min and let stand for 12h; filter, dry at 105℃ for 24h and then calcine in a muffle furnace at a calcination temperature of 250℃ (heating rate 5℃ / min) for 3h, and then cool naturally to room temperature to obtain the modified MOF.

[0074] Comparative Example 1

[0075] The high-strength, crack-resistant, and corrosion-resistant castable in this comparative example comprises the following components by weight: 1.2 kg dense corundum (composed of 0.6 kg of dense corundum with a particle size of 5-8 mm and 0.6 kg of dense corundum with a particle size of 3-5 mm), 2.2 kg brown corundum (composed of 1.2 kg of brown corundum with a particle size of 1-3 mm and 1 kg of brown corundum with a particle size of 0-1 mm), 1.4 kg white corundum with a particle size of 325 mesh, 2.1 kg bauxite (composed of 1.2 kg of bauxite with a particle size of 3-5 mm and 0.9 kg of bauxite with a particle size of 1-3 mm), 1.4 kg silicon carbide (composed of 0.7 kg of silicon carbide with a particle size of 1-3 mm and 0.7 kg of silicon carbide with a particle size of 325 mesh), 0.8 kg activated alumina, 0.15 kg spherical asphalt, 0.5 kg pure calcium aluminate cement, 20 g sodium hexametaphosphate, 0.2 kg antioxidant, and 0.6 kg composite additives.

[0076] The preparation method of the high-strength crack-resistant and corrosion-resistant castable in this comparative example is the same as that in Example 2.

[0077] The preparation method of the composite additive in this comparative example is as follows:

[0078] A1. 2g of modified MOF was ultrasonically dispersed in deionized water to prepare a modified MOF suspension.

[0079] A2, 4.88g MgCl2·6H2O and 3g Al(NO3)3·9H2O were poured into a beaker, and 60mL of distilled water was added to prepare a layered bimetallic hydroxide precursor; 0.46g ammonium dihydrogen phosphate and 2.56g NaOH were poured into a beaker, and 30mL of distilled water was added and stirred to prepare solution 1.

[0080] A3. The layered bimetallic hydroxide precursor was slowly added dropwise to the modified MOF suspension and stirred vigorously for 1 hour. Then, while stirring, solution 1 was slowly added dropwise at a rate of 0.5 mL / min to maintain the pH at 8-9. The mixture was stirred for 30 minutes and aged at 60°C for 10 hours. After aging, the mixture was filtered, washed with distilled water until the pH reached 7, and then dried at 100°C for 6 hours to obtain the composite additive.

[0081] The modified MOF used in this comparative example was prepared by the following method:

[0082] 1) Dissolve 0.93 g zirconium tetrachloride (4 mmol) in 15 mL DMF, heat to 80 °C, and maintain for 30 min to obtain solution A; add 0.33 g terephthalic acid (2 mmol) to 15 mL DMF solution, heat to 80 °C, and maintain for 30 min to obtain solution B;

[0083] 2) Mix solution A and solution B under ultrasonic treatment for 10 min to obtain a mixed solution; transfer the mixed solution to a high-pressure vessel lined with polytetrafluoroethylene and react at 120℃ for 24 h. After the reaction is completed, cool to room temperature, collect the precipitate by centrifugation, wash with DMF and ethanol, and vacuum dry at 75℃ for 12 h to obtain modified MOF.

[0084] Comparative Example 2

[0085] The high-strength, crack-resistant, and corrosion-resistant castable in this comparative example comprises the following components by weight: 1.2 kg dense corundum (composed of 0.6 kg of dense corundum with a particle size of 5-8 mm and 0.6 kg of dense corundum with a particle size of 3-5 mm), 2.2 kg brown corundum (composed of 1.2 kg of brown corundum with a particle size of 1-3 mm and 1 kg of brown corundum with a particle size of 0-1 mm), 1.4 kg white corundum with a particle size of 325 mesh, 2.1 kg bauxite (composed of 1.2 kg of bauxite with a particle size of 3-5 mm and 0.9 kg of bauxite with a particle size of 1-3 mm), 1.4 kg silicon carbide (composed of 0.7 kg of silicon carbide with a particle size of 1-3 mm and 0.7 kg of silicon carbide with a particle size of 325 mesh), 0.8 kg activated alumina, 0.15 kg spherical asphalt, 0.5 kg pure calcium aluminate cement, 20 g sodium hexametaphosphate, 0.2 kg antioxidant, and 0.6 kg composite additives.

[0086] The preparation method of the high-strength crack-resistant and corrosion-resistant castable in this comparative example is the same as that in Example 2.

[0087] The preparation method of the composite additive in this comparative example is as follows:

[0088] A1. Take 4.88g MgCl2·6H2O and 3g Al(NO3)3·9H2O into a beaker, add 60mL of distilled water to prepare a layered bimetallic hydroxide precursor; take 0.46g ammonium dihydrogen phosphate and 2.56g NaOH into a beaker, add 30mL of distilled water and stir to prepare solution 1.

[0089] A2, under stirring, solution 1 was slowly added dropwise to the layered bimetallic hydroxide precursor at a rate of 0.5 mL / min, maintaining the pH at 8-9, stirring for 30 min, aging at 60 °C for 10 h, filtering after aging, washing with distilled water until the pH reached 7, and then drying at 100 °C for 6 h to obtain the composite additive.

[0090] Performance testing

[0091] The bulk density of high-strength crack-resistant and corrosion-resistant castables was tested according to GB / T 2997-2015; the room temperature flexural strength of high-strength crack-resistant and corrosion-resistant castables was tested according to GB / T 3001-2007; the compressive strength of high-strength crack-resistant and corrosion-resistant castables was tested according to GB / T 5072-2008; the high temperature flexural strength of high-strength crack-resistant and corrosion-resistant castables was tested according to GB / T 3002-2004; and the erosion index (percentage of eroded area) of high-strength crack-resistant and corrosion-resistant castables was tested according to GB / T8931-2007.

[0092] Table 1. Performance test results of high-strength crack-resistant and corrosion-resistant castables in Examples 1-3 and Comparative Examples 1-2

[0093]

[0094] Analyze Examples 1-3 and Comparative Examples 1-2, in conjunction with Table 1 and Figures 1-4 It can be seen that the composite additive, through the modification of MOF with monocarboxylic acid and the loading of CeO2 and phosphate intercalated layered bimetallic hydroxide, can effectively enhance the bulk density, high-temperature flexural strength and corrosion resistance of high-strength crack-resistant and corrosion-resistant castable.

[0095] Analysis Table 1 and Figures 1-3 Compared to Examples 1-3, the high-strength crack-resistant and corrosion-resistant castable prepared in Comparative Example 1 did not contain monocarboxylic acid and cerium nitrate hexahydrate in the modified MOF of the composite additive, which reduced the bonding force with the phosphate intercalated layered bimetallic hydroxide, thus resulting in a decrease in the bulk density of the high-strength crack-resistant and corrosion-resistant castable in Comparative Example 1. Compared to Examples 1-3, the high-strength crack-resistant and corrosion-resistant castable prepared in Comparative Example 2 did not contain modified MOF in the composite additive, and ZrO2 could not be formed after calcination, thus resulting in a decrease in the bulk density and high-temperature flexural strength, and an increase in the erosion index of the high-strength crack-resistant and corrosion-resistant castable in Comparative Example 2.

[0096] analyze Figure 4 It can be observed that the modified MOF has new peaks compared to the original MOF, which are (111), (200), (220), and (311) crystal planes, which correspond completely to the CeO2 peak, indicating that the modified MOF was successfully prepared.

[0097] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high-strength, crack-resistant, and corrosion-resistant castable, characterized in that, The composition by weight is as follows: 11-13 parts dense corundum, 21-23 parts brown corundum, 13-15 parts white corundum, 20-22 parts bauxite, 13-15 parts silicon carbide, 7-9 parts activated alumina, 1-2.5 parts spherical asphalt, 4-6 parts pure calcium aluminate cement, 0.1-0.3 parts sodium hexametaphosphate, 1-2 parts antioxidant, and 5-7 parts composite additives. The composite additive is prepared by combining a layered bimetallic hydroxide with a modified MOF; The layered bimetallic hydroxide forms a magnesium-aluminum composite oxide after calcination. The preparation method of the modified MOF includes the following steps: 1) dissolving zirconium tetrachloride in DMF to obtain solution A; adding a monocarboxylic acid to DMF, dissolving it, adding terephthalic acid, stirring and dissolving to obtain solution B; 2) ultrasonically mixing solution A and solution B, reacting, washing and drying to obtain monocarboxylic acid modified MOF; 3) adding the monocarboxylic acid modified MOF to cerium nitrate solution, calcining to obtain modified MOF.

2. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 1, characterized in that, The preparation method of the composite additive includes the following steps: A1, ultrasonically dispersing the modified MOF in deionized water to obtain a modified MOF suspension; A2, dissolving MgCl2·6H2O and Al(NO3)3·9H2O in distilled water to obtain a layered bimetallic hydroxide precursor; dissolving ammonium dihydrogen phosphate and NaOH in distilled water to obtain solution 1; A3, slowly adding the layered bimetallic hydroxide precursor to the modified MOF suspension, stirring vigorously for 1 hour, then adding solution 1, aging, filtration, washing, and drying to obtain the final product.

3. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 2, characterized in that, In A3, the mass ratio of the layered bimetallic hydroxide precursor to the modified MOF is 3-4.5:

1.

4. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 1, characterized in that, In 1), the monocarboxylic acid is octanoic acid or butyric acid.

5. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 1, characterized in that, In step 2), the molar ratio of zirconium tetrachloride to terephthalic acid to monocarboxylic acid in solutions A and B is 1:0.5-1:20-25.

6. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 1, characterized in that, In step 3), the mass ratio of the monocarboxylic acid-modified MOF to cerium nitrate hexahydrate is 1:3-5.

7. The high-strength, crack-resistant, and corrosion-resistant castable according to claim 1, characterized in that, The dense corundum is composed of a mixture of dense corundum with a particle size of 5-8 mm and dense corundum with a particle size of 3-5 mm; the brown corundum is composed of a mixture of brown corundum with a particle size of 1-3 mm and brown corundum with a particle size of 0-1 mm; the white corundum has a particle size of 325 mesh; the bauxite is composed of a mixture of bauxite with a particle size of 3-5 mm and bauxite with a particle size of 1-3 mm; the silicon carbide is composed of a mixture of silicon carbide with a particle size of 1-3 mm and silicon carbide with a particle size of 325 mesh.

8. A method for preparing a high-strength, crack-resistant, and corrosion-resistant castable as described in any one of claims 1-7, characterized in that, The process includes the following steps: S1, weigh each raw material according to the ratio, dry mix them, add deionized water and wet mix them to obtain a mixed slurry; S2, inject the mixed slurry into a mold, vibrate to form it, cure it in the mold and then demold it to obtain a blank; S3, dry the blank and then calcine it at high temperature to obtain the blank.

9. The method for preparing a high-strength, crack-resistant, and corrosion-resistant castable according to claim 8, characterized in that: In S3, the high-temperature calcination involves heating to 1000℃-1100℃ at a rate of 3℃ / min, holding at that temperature for 3 hours, and then heating to 1400℃-1500℃ at a rate of 5℃ / min, holding at that temperature for 3 hours.

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