High-strength calcium hexaluminate light material and preparation process thereof

Abstract

The invention relates to the technical field of refractory materials, and discloses a high-strength calcium hexaluminate light material and a preparation process thereof. The preparation method comprises the following steps: S1, mixing calcium carbonate and aluminum hydroxide, adding water, sodium tripolyphosphate and dextrin, and carrying out ball milling, spray granulation and calcination to obtain porous balls; s2, zirconium oxide is taken to be subjected to acid activation treatment and electroplating and coated with CaCO3, and a composite material is obtained; in a nitrogen environment, uniformly mixing methacrylic acid, methacrylamide, a modifier, 3-(methacryloyloxy) propyltrimethoxysilane and azodiisobutyronitrile, stirring at 70-80 DEG C for 8-12 hours, under an acidic condition, adding the composite material and water, stirring at 70-80 DEG C for 8-12 hours, removing a solvent, and drying to obtain a modified composite material; and S3, mixing the porous balls, the modified composite material and alumina powder, adding dextrin, uniformly stirring, carrying out compression molding, and calcining to obtain the high-strength calcium hexaluminate lightweight material.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials and discloses a high-strength lightweight calcium hexaaluminate material and a preparation process thereof. Background Art

[0002] Calcium hexaaluminate is an important refractory material with advantages such as low thermal conductivity, high strength, and good chemical stability. It is widely used in high-temperature industries such as steel, aluminum smelting, ceramics, and petrochemicals. Lightweight calcium hexaaluminate has superior thermal insulation properties and can significantly reduce material density, thereby reducing structural weight, meeting the needs of energy conservation and emission reduction.

[0003] To compensate for the reduced strength associated with lightweighting, existing technologies often incorporate zirconium oxide to improve corrosion resistance and mechanical strength. However, the contact between zirconium oxide and calcium hexaaluminate needs to be improved. Due to issues with bonding and dispersion, directly adding untreated zirconium oxide can lead to unstable performance. Therefore, developing a lightweight calcium hexaaluminate material with stable performance and high strength, as well as a process for its preparation, is of great significance. Summary of the Invention

[0004] The object of the present invention is to provide a high-strength lightweight calcium hexaaluminate material and a preparation process thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a preparation process of a high-strength calcium hexaaluminate lightweight material, comprising the following steps: S1: mixing calcium carbonate and aluminum hydroxide, adding water, sodium tripolyphosphate, and dextrin, and ball milling for 3 to 4 hours to obtain a mixed slurry; spray granulating the mixed slurry, and calcining it at 1100 to 1200°C to obtain porous balls; the bulk density of the porous balls is ≤0.7g / cm 3 , particle size is 0.044~0.3mm;

[0006] S2: Take zirconium oxide and perform acid activation treatment. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process adopts 8A / dm 2 The composite material is then cleaned, electroplated, and coated with CaCO3 to obtain a composite material; methacrylic acid, methacrylamide, a modifier, 3-(isobutyleneoxy)propyltrimethoxysilane, and azobisisobutyronitrile are uniformly mixed under a nitrogen environment, stirred at 70-80° C. for 8-12 hours, and the composite material and water are added under acidic conditions, stirred at 70-80° C. for 8-12 hours, the solvent is removed, and the composite material is dried to obtain a modified composite material;

[0007] S3: The porous balls, alumina powder and modified composite materials are mixed, dextrin is added and stirred evenly, and then pressed into shape at 10 MPa. The mixture is calcined at 1300-1500°C for 8-10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0008] More optimally, the mixed slurry includes the following raw materials, calculated by mass: 30-40 parts of calcium carbonate, 60-70 parts of aluminum hydroxide, 80-90 parts of water, 0.05-0.08 parts of sodium tripolyphosphate, and 3-6 parts of dextrin.

[0009] More optimally, the plating solution used for electroplating contains: 80-100 g / L of ferric sulfate, 30-35 g / L of magnesium sulfate, 60-80 g / L of nickel chloride, 4-10 g / L of titanyl sulfate, 4-10 g / L of samarium nitrate, 10-20 g / L of molybdenum powder, 10-20 g / L of Y2O3 powder, 45-50 g / L of boric acid, 10-20 g / L of silicon nitride powder, 55-80 g / L of citric acid, 3-6 g / L of triethylenetetramine, 1-3 g / L of octylphenyl polyoxyethylene ether, and the remainder is water;

[0010] Electroplating process: current density 1~3A / dm 2 , electroplating temperature 25 ~ 30 ℃, electroplating time 5 ~ 10min.

[0011] More optimally, the specific steps of CaCO3 coating are: adding calcium carbonate to a citric acid aqueous solution, ultrasonically vibrating, to obtain a precursor impregnation solution; after the zirconium oxide is acid-activated and electroplated, it is placed in the precursor impregnation solution for full immersion, dried at 80°C, and kept warm at 430-500°C for 10-20 hours to obtain CaCO3-coated modified zirconium oxide, which is named a composite material.

[0012] More optimally, the precursor impregnation solution includes the following raw materials, calculated by mass: 5 to 8 parts of calcium carbonate and 1000 parts of citric acid aqueous solution with a concentration of 0.15 to 0.2 mol / L.

[0013] More optimally, the modified composite material includes the following raw materials, calculated by mass: 10 to 15 parts of methacrylic acid, 6 to 8 parts of methacrylamide, 4 to 6 parts of modifier, 20 to 30 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, 0.5 to 1 part of azobisisobutyronitrile, 20 to 30 parts of composite material, and 10 to 20 parts of water.

[0014] More optimally, the preparation of the modifier includes the following steps: taking hydroxyethyl acrylate, adding it to a mixed solution of water and DMSO (the volume ratio of water to DMSO is 1:1) and stirring evenly, adding 3,5-diformylphenylboronic acid pinacol ester, adjusting the pH to 3-4, heating to 70-80°C and stirring for 8-10 hours, removing the solvent, and obtaining the modifier.

[0015] More optimally, the modifier includes the following raw materials, calculated by mass: 25 to 35 parts of hydroxyethyl acrylate, 100 parts of a mixed solution of water and DMSO, and 25 to 30 parts of 3,5-diformylphenylboronic acid pinacol ester.

[0016] More optimally, the high-strength calcium hexaaluminate lightweight material includes the following raw materials, calculated by mass: 30 to 40 parts of porous balls, 3 to 6 parts of dextrin, 50 to 60 parts of alumina powder, and 20 to 30 parts of modified composite material mixture.

[0017] Compared with the existing technology, the beneficial effects achieved by the present invention are: (1) the porous structure significantly reduces the density of the material and reduces the weight of the structure; (2) the additional addition of modified composite materials compensates for the strength reduction problem caused by lightweighting. The specific preparation method is: after activating zirconium oxide, electroplating is performed to obtain modified zirconium oxide: metal elements such as iron, magnesium, and nickel are introduced to enhance the crystal structure, thereby improving thermal shock resistance and toughness; rare earth elements are introduced at the same time, and the addition of samarium can promote the development of calcium hexaaluminate crystals and improve flexural strength; molybdenum as a transition element helps to eliminate residual stress and enhance bonding strength; yttrium has the effect of refining grains and improving thermal shock resistance. In order to improve bonding strength, a layer of calcium carbonate is coated on the surface of the modified zirconium oxide to obtain a composite material, which improves the contact between the porous balls and alumina powder and makes the bonding closer. Furthermore, the composite material is modified with methacrylic acid, methacrylamide, a modifier, and KH570 to improve the agglomeration phenomenon; on the other hand, the flame retardant properties are increased by introducing elements such as B and N; the modifier is 3,5-diformylphenylboronic acid pinacol ester modified with hydroxyethyl acrylate, which has a certain steric hindrance and further improves the dispersibility, but the added amount should not be too much, otherwise it will affect the overall structure. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] It should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions, and illustratively include: ethanol (CAS: 64-17-5); calcium carbonate (nano calcium carbonate M81760, brand: Mairui); aluminum hydroxide (M10708, brand: Mairui); sodium tripolyphosphate (CAS: 7758-29-4); dextrin (S11008, brand: Yuanye); titanyl sulfate (S41632, brand: Yuanye); samarium nitrate (CAS: 10361-83-8); molybdenum powder (nano molybdenum powder, specific surface area 3-8m2 / g, particle size 80-200nm, 99.9%, brand: Kramar); Y2O3 powder (C01, 20-30nm, brand: Yumu Nano); silicon nitride micropowder (YQ-S31, brand: Yuanqin); octylphenyl polyoxyethylene ether (CAS: 9002-93-1); DMSO (dimethyl sulfoxide); 3,5-diformylphenylboronic acid pinacol ester (CAS: 945865-80-5); 3-(Isomethylacryloyloxy)propyltrimethoxysilane (CAS: 2530-85-0); alumina powder (Zhongtianli GNAO);

[0020] Unless otherwise specified, the following are parts by mass and mass ratios;

[0021] Example 1: S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide were mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin were added, and the mixture was ball-milled for 3 hours to obtain a mixed slurry; the mixed slurry was spray-granulated to obtain a spherical body; the spherical body was calcined at 1100°C to obtain a porous ball; the bulk density of the porous ball was 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0022] S2: Take zirconium oxide and perform acid activation treatment on the surface. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process is carried out with 8A / dm 2 The current shock was applied for 2 minutes; after activation, the surface was cleaned and electroplated to obtain modified zirconium oxide; the electroplating solution used contained: 80g / L ferric sulfate, 35g / L magnesium sulfate, 60g / L nickel chloride, 8g / L titanyl sulfate, 8g / L samarium nitrate, 10g / L molybdenum powder, 15g / L Y2O3 powder, 50g / L boric acid, 15g / L silicon nitride powder, 70g / L citric acid, 5g / L triethylenetetramine, and 2g / L octylphenyl polyoxyethylene ether; the current density of the electroplating process was 2A / dm 2 , electroplating temperature 25℃, electroplating time 6min;

[0023] S3: Add 6 parts of calcium carbonate to 1000 parts of a 0.2 mol / L citric acid aqueous solution and ultrasonically vibrate for 30 minutes to obtain a precursor impregnation solution; fully impregnate the modified zirconia in the precursor impregnation solution, dry it at 80°C, and keep it at 450°C for 18 hours to obtain CaCO3-coated modified zirconia, which is named a composite material;

[0024] S4: 30 parts of hydroxyethyl acrylate were added to a mixed solution of 100 parts of water and DMSO (volume ratio 1:1), stirred evenly, 25 parts of 3,5-diformylphenylboronic acid pinacol ester were added, the pH was adjusted to 3, the temperature was raised to 75°C and stirred for 10 hours, and the solvent was removed to obtain a modifier;

[0025] S5: Under a nitrogen environment, 12 parts of methacrylic acid, 8 parts of methacrylamide, 5 parts of a modifier, 25 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutyronitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 25 parts of the composite material and 10 parts of water were added, and the mixture was stirred at 80°C for 10 hours. The solvent was removed and the mixture was dried to obtain a modified composite material;

[0026] S6: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0027] Example 2: S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide were mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin were added, and the mixture was ball-milled for 3 hours to obtain a mixed slurry; the mixed slurry was spray-granulated to obtain a spherical body; the spherical body was calcined at 1100°C to obtain a porous ball; the bulk density of the porous ball was 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0028] S2: Take zirconium oxide and perform acid activation treatment on the surface. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process is carried out with 8A / dm 2 The current shock was applied for 2 minutes; after activation, the mixture was cleaned and electroplated to obtain modified zirconium oxide; the electroplating solution used contained: 100g / L ferric sulfate, 30g / L magnesium sulfate, 60g / L nickel chloride, 4g / L titanyl sulfate, 10g / L samarium nitrate, 15g / L molybdenum powder, 10g / L Y2O3 powder, 45g / L boric acid, 10g / L silicon nitride powder, 80g / L citric acid, 5g / L triethylenetetramine, and 2g / L octylphenyl polyoxyethylene ether; the current density of the electroplating process was 1A / dm 2 , electroplating temperature 30℃, electroplating time 8min;

[0029] S3: 8 parts of calcium carbonate were added to 1000 parts of a 0.2 mol / L aqueous citric acid solution, and ultrasonically vibrated for 30 minutes to obtain a precursor impregnation solution; the modified zirconia was fully impregnated in the precursor impregnation solution, dried at 80°C, and kept at 450°C for 18 hours to obtain CaCO3-coated modified zirconia, which was named a composite material;

[0030] S4: Take 25 parts of hydroxyethyl acrylate, add it to a mixed solution of 100 parts of water and DMSO (volume ratio 1:1), stir evenly, add 25 parts of 3,5-diformylphenylboronic acid pinacol ester, adjust the pH to 3, heat to 75°C and stir for 10 hours, remove the solvent to obtain a modifier;

[0031] S5: Under a nitrogen environment, 10 parts of methacrylic acid, 8 parts of methacrylamide, 6 parts of a modifier, 30 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutyronitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 30 parts of the composite material and 10 parts of water were added, and the mixture was stirred at 80°C for 10 hours. The solvent was removed and the mixture was dried to obtain a modified composite material;

[0032] S6: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0033] Comparative Example 1 (using zirconium oxide instead of the composite material, and the remaining steps are consistent with Example 1): S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide are mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin are added, and ball milling is carried out for 3 hours to obtain a mixed slurry; the mixed slurry is spray granulated to obtain a spherical body; the spherical body is calcined at 1100°C to obtain a porous ball; the bulk density of the porous ball is 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0034] S2: 30 parts of hydroxyethyl acrylate were added to a mixed solution of 100 parts of water and DMSO (volume ratio 1:1), stirred evenly, and 25 parts of 3,5-diformylphenylboronic acid pinacol ester were added. The pH was adjusted to 3, and the mixture was heated to 75°C and stirred for 10 hours. The solvent was removed to obtain a modifier.

[0035] S3: Under a nitrogen environment, 12 parts of methacrylic acid, 8 parts of methacrylamide, 5 parts of a modifier, 25 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutylonitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 25 parts of zirconium oxide and 10 parts of water were added, and the mixture was stirred at 80°C for 10 hours. The solvent was removed and the mixture was dried to obtain a modified composite material;

[0036] S4: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0037] Comparative Example 2 (changing the electroplating solution formula, the rest of the method steps are the same as Example 1): S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide are mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin are added, and ball milling is carried out for 3 hours to obtain a mixed slurry; the mixed slurry is spray granulated to obtain a spherical body; the spherical body is calcined at 1100°C to obtain a porous ball; the bulk density of the porous ball is 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0038] S2: Take zirconium oxide and perform acid activation treatment on the surface. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process is carried out with 8A / dm 2 The current shock was applied for 2 minutes; after activation, the surface was cleaned and electroplated to obtain modified zirconium oxide; the electroplating solution used contained: 80g / L ferric sulfate, 35g / L magnesium sulfate, 60g / L nickel chloride, 8g / L titanyl sulfate, 50g / L boric acid, 30g / L silicon nitride powder, 70g / L citric acid, 5g / L triethylenetetramine, and 2g / L octylphenyl polyoxyethylene ether; the current density of the electroplating process was 2A / dm 2 , electroplating temperature 25℃, electroplating time 6min;

[0039] S3: Add 6 parts of calcium carbonate to 1000 parts of a 0.2 mol / L citric acid aqueous solution and ultrasonically vibrate for 30 minutes to obtain a precursor impregnation solution; fully impregnate the modified zirconia in the precursor impregnation solution, dry it at 80°C, and keep it at 450°C for 18 hours to obtain CaCO3-coated modified zirconia, which is named a composite material;

[0040] S4: 30 parts of hydroxyethyl acrylate were added to a mixed solution of 100 parts of water and DMSO (volume ratio 1:1), stirred evenly, 25 parts of 3,5-diformylphenylboronic acid pinacol ester were added, the pH was adjusted to 3, the temperature was raised to 75°C and stirred for 10 hours, and the solvent was removed to obtain a modifier;

[0041] S5: Under a nitrogen environment, 12 parts of methacrylic acid, 8 parts of methacrylamide, 5 parts of a modifier, 25 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutyronitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 25 parts of the composite material and 10 parts of water were added, and the mixture was stirred at 80°C for 10 hours. The solvent was removed and the mixture was dried to obtain a modified composite material;

[0042] S6: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0043] Comparative Example 3 (no modifier is added, and the remaining steps are the same as those in Example 1): S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide are mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin are added, and ball milling is performed for 3 hours to obtain a mixed slurry; the mixed slurry is spray granulated to obtain a spherical body; the spherical body is calcined at 1100° C. to obtain a porous ball; the bulk density of the porous ball is 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0044] S2: Take zirconium oxide and perform acid activation treatment on the surface. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process is carried out with 8A / dm 2 The current shock was applied for 2 minutes; after activation, the surface was cleaned and electroplated to obtain modified zirconium oxide; the electroplating solution used contained: 80g / L ferric sulfate, 35g / L magnesium sulfate, 60g / L nickel chloride, 8g / L titanyl sulfate, 8g / L samarium nitrate, 10g / L molybdenum powder, 15g / L Y2O3 powder, 50g / L boric acid, 15g / L silicon nitride powder, 70g / L citric acid, 5g / L triethylenetetramine, and 2g / L octylphenyl polyoxyethylene ether; the current density of the electroplating process was 2A / dm 2 , electroplating temperature 25℃, electroplating time 6min;

[0045] S3: Add 6 parts of calcium carbonate to 1000 parts of a 0.2 mol / L citric acid aqueous solution and ultrasonically vibrate for 30 minutes to obtain a precursor impregnation solution; fully impregnate the modified zirconia in the precursor impregnation solution, dry it at 80°C, and keep it at 450°C for 18 hours to obtain CaCO3-coated modified zirconia, which is named a composite material;

[0046] S4: Under a nitrogen environment, 18 parts of methacrylic acid, 8 parts of methacrylamide, 25 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutyronitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 25 parts of the composite material and 10 parts of water were added, and the mixture was stirred at 80°C for 10 hours. The solvent was removed and the mixture was dried to obtain a modified composite material;

[0047] S5: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0048] Comparative Example 4 (CaCO3 coating is not performed, and the remaining steps are consistent with Example 1): S1: 38 parts of calcium carbonate and 62 parts of aluminum hydroxide are mixed, 80 parts of water, 0.05 parts of sodium tripolyphosphate, and 4 parts of dextrin are added, and ball milling is performed for 3 hours to obtain a mixed slurry; the mixed slurry is spray granulated to obtain a spherical body; the spherical body is calcined at 1100°C to obtain a porous ball; the bulk density of the porous ball is 0.63 g / cm 3 , particle size is 0.044~0.3mm;

[0049] S2: Take zirconium oxide and perform acid activation treatment on the surface. The activation solution used in the acid activation treatment contains 80g / L NiCl2 and 40g / L HCl, and the rest is water. The activation process is carried out with 8A / dm 2 The current shock was applied for 2 minutes; after activation, the surface was cleaned and electroplated to obtain modified zirconium oxide; the electroplating solution used contained: 80g / L ferric sulfate, 35g / L magnesium sulfate, 60g / L nickel chloride, 8g / L titanyl sulfate, 8g / L samarium nitrate, 10g / L molybdenum powder, 15g / L Y2O3 powder, 50g / L boric acid, 15g / L silicon nitride powder, 70g / L citric acid, 5g / L triethylenetetramine, and 2g / L octylphenyl polyoxyethylene ether; the current density of the electroplating process was 2A / dm 2 , electroplating temperature 25℃, electroplating time 6min;

[0050] S3: Take 30 parts of hydroxyethyl acrylate, add it to a mixed solution of 100 parts of water and DMSO (volume ratio 1:1), stir evenly, add 25 parts of 3,5-diformylphenylboronic acid pinacol ester, adjust the pH to 3, heat to 75°C and stir for 10 hours, remove the solvent to obtain a modifier;

[0051] S4: Under a nitrogen environment, 12 parts of methacrylic acid, 8 parts of methacrylamide, 5 parts of a modifier, 25 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, and 0.8 parts of azobisisobutyronitrile were mixed uniformly, and stirred at 80°C for 10 hours. Under acidic conditions, 25 parts of modified zirconium oxide and 10 parts of water were added, and stirred at 80°C for 10 hours. The solvent was removed and dried to obtain a modified composite material;

[0052] S5: Mix 35 parts of porous balls, 60 parts of alumina powder, and 25 parts of modified composite materials, add 5 parts of dextrin, stir evenly, press into shape at a pressure of 10 MPa, and calcine at 1400°C for 10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

[0053] Performance test: Take the high-strength calcium hexaaluminate lightweight material prepared in Examples 1 to 2 and Comparative Examples 1 to 4; (1) With reference to GB / T30873-2014, a sample with a size of 230 mm × 114 mm × 65 mm was prepared and tested: 1100°C was kept warm for 20 minutes, then immersed in 20°C running water to cool for 3 minutes, placed in air for 5 minutes, and then heated to 1100°C; the above test process was repeated until half of the heated end face of the sample was broken, and the thermal shock resistance number was obtained; (2) Flexural strength test: With reference to GB / T3002-2017, a sample with a size of 150 mm × 25 mm × 25 mm was prepared, placed in an experimental furnace, heated to 1500°C and kept warm for 25 minutes, and the above knife edge was uniformly loaded vertically in the middle of the pressure surface of the sample until it broke, and the maximum load when the sample broke was recorded to obtain the flexural strength; (3) 1600°C was kept warm for 6 hours, and the permanent linear change rate after firing was measured; see the table for details;

[0054]

[0055] Conclusion: Comparative Example 1 replaces the composite material with zirconium oxide without additional treatment, and the performance is greatly reduced; Comparative Example 2 changes the electroplating solution formula, that is, there is no rare earth element, which also leads to a decline in performance; Comparative Example 3 does not add a modifier, and the performance is reduced due to dispersion and other problems; Comparative Example 4 does not perform CaCO3 coating, and the bonding force is reduced, resulting in a decline in performance; In summary, the high-strength calcium hexaaluminate lightweight material prepared by the present invention has good strength and thermal shock resistance, and maintains good high-temperature volume stability while being lightweight.

[0056] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are 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 will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing a high-strength lightweight calcium hexaaluminate material, characterized by: The following steps are involved: S1: Calcium carbonate and aluminum hydroxide are mixed, water, sodium tripolyphosphate, and dextrin are added, and the mixture is ball-milled for 3-4 hours to obtain a mixed slurry; the mixed slurry is spray-granulated and calcined at 1100-1200°C to obtain porous balls; S2: zirconium oxide is acid-activated, electroplated, and coated with CaCO3 to obtain a composite material; methacrylic acid, methacrylamide, a modifier, 3-(isobutyleneoxy)propyltrimethoxysilane, and azobisisobutyronitrile are mixed uniformly under a nitrogen environment, stirred at 70-80°C for 8-12 hours, and the composite material and water are added under acidic conditions, stirred at 70-80°C for 8-12 hours, the solvent is removed, and the mixture is dried to obtain a modified composite material; S3: The porous balls, alumina powder and modified composite materials are mixed, dextrin is added and stirred evenly, and then pressed into shape. The mixture is calcined at 1300-1500° C. for 8-10 hours to obtain a high-strength calcium hexaaluminate lightweight material.

2. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The mixed slurry includes the following raw materials, calculated by mass: 30-40 parts of calcium carbonate, 60-70 parts of aluminum hydroxide, 80-90 parts of water, 0.05-0.08 parts of sodium tripolyphosphate, and 3-6 parts of dextrin.

3. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The plating solution used for electroplating contains: 80-100 g / L of ferric sulfate, 30-35 g / L of magnesium sulfate, 60-80 g / L of nickel chloride, 4-10 g / L of titanyl sulfate, 4-10 g / L of samarium nitrate, 10-20 g / L of molybdenum powder, 10-20 g / L of Y2O3 powder, 45-50 g / L of boric acid, 10-20 g / L of silicon nitride powder, 55-80 g / L of citric acid, 3-6 g / L of triethylenetetramine, 1-3 g / L of octylphenyl polyoxyethylene ether, and the remainder is water; Electroplating process: current density 1~3A / dm 2 , electroplating temperature 25 ~ 30 ℃, electroplating time 5 ~ 10min.

4. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The specific steps of coating with CaCO3 are as follows: adding calcium carbonate to a citric acid aqueous solution, ultrasonically vibrating, and obtaining a precursor impregnation solution; after the zirconium oxide is acid-activated and electroplated, it is placed in the precursor impregnation solution for full immersion, dried, and kept warm at 430-500°C for 10-20 hours to obtain CaCO3-coated modified zirconium oxide, which is named a composite material.

5. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 4, characterized in that: The precursor impregnation solution includes the following raw materials, calculated by mass: 5 to 8 parts of calcium carbonate and 1000 parts of citric acid aqueous solution with a concentration of 0.15 to 0.2 mol / L.

6. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The modified composite material includes the following raw materials, calculated by mass: 10 to 15 parts of methacrylic acid, 6 to 8 parts of methacrylamide, 4 to 6 parts of a modifier, 20 to 30 parts of 3-(isomethacryloyloxy)propyltrimethoxysilane, 0.5 to 1 part of azobisisobutyronitrile, 20 to 30 parts of a composite material, and 10 to 20 parts of water.

7. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The preparation of the modifier comprises the following steps: Take hydroxyethyl acrylate, add it to a mixed solution of water and DMSO and stir evenly, add 3,5-diformylphenylboronic acid pinacol ester, adjust the pH to 3-4, heat to 70-80°C and stir for 8-10 hours, remove the solvent to obtain a modifier.

8. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 7, characterized in that: The modifier comprises the following raw materials, calculated by mass: 25 to 35 parts of hydroxyethyl acrylate, 100 parts of a mixed solution of water and DMSO, and 25 to 30 parts of 3,5-diformylphenylboronic acid pinacol ester.

9. The process for preparing a high-strength lightweight calcium hexaaluminate material according to claim 1, characterized in that: The high-strength calcium hexaaluminate lightweight material comprises the following raw materials, calculated by mass: 30-40 parts of porous balls, 3-6 parts of dextrin, 50-60 parts of alumina powder, and 20-30 parts of modified composite materials.

10. A high-strength lightweight calcium hexaaluminate material prepared according to the process for preparing a high-strength lightweight calcium hexaaluminate material according to any one of claims 1 to 9.

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