High-strength erosion-resistant low-carbon magnesia-carbon brick and preparation method thereof

Abstract

The application belongs to the technical field of refractory materials, and particularly relates to high-strength erosion-resistant low-carbon magnesia-carbon brick and a preparation method thereof. The low-carbon magnesia-carbon brick comprises the following components in parts by weight: 60-70 parts of fused magnesia particles; 15-20 parts of fused magnesia fine powder; 1-3 parts of flaky graphite; 3-5 parts of antioxidant; and 2-4 parts of modified phenolic resin. The low-carbon magnesia-carbon brick has good high-temperature strength, oxidation resistance and erosion resistance, and helps to prolong the service life of the low-carbon magnesia-carbon brick.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory materials, and particularly relates to a high-strength erosion-resistant low-carbon magnesia-carbon brick and a preparation method thereof. BACKGROUND

[0002] Magnesia-carbon brick is a kind of composite refractory material, which is made of high-melting-point basic oxide magnesium oxide and high-melting-point carbon material difficult to be eroded by slag as raw materials, and various non-oxide additives are added, and the magnesia-carbon brick has excellent thermal shock resistance, slag erosion resistance and slag penetration resistance, and is widely used in the inner lining of converter, alternating current electric arc furnace, direct current electric arc furnace, slag line of ladle and other parts; however, the traditional magnesia-carbon brick has a high carbon content, generally between 10-20%, and there are problems such as a large amount of carbon pickup of molten steel and oxidation failure during use, how to reduce the carbon content of the magnesia-carbon brick has become a research hotspot, however, with the reduction of the carbon content, the erosion resistance, slag penetration resistance and thermal shock stability of the magnesia-carbon brick are affected, and various additives are usually used to improve the performance of the low-carbon magnesia-carbon brick.

[0003] A low-carbon magnesia-carbon brick is disclosed in a patent with application number 202211503195.2, and the low-carbon magnesia-carbon brick comprises a mixture of the following components by weight: 63-70 parts of fused magnesia particles, 23-30 parts of fused magnesia fine powder, 0-3 parts of flake graphite, 1-4 parts of ZrB2-C composite powder, 3 parts of aluminum powder and 4 parts of phenolic resin, the carbon content is reduced by replacing all or part of the graphite with the ZrB2-C composite powder, and the room temperature strength and high-temperature oxidation resistance of the material are effectively improved; a patent with application number 202310435582.5 discloses an anti-cracking magnesia-carbon brick and a preparation method thereof, and the magnesia-carbon brick comprises the following components by weight: 60-0 parts of fused magnesia particles, 10-20 parts of fused magnesia fine powder, 10-20 parts of graphite, 0.1-1 parts of calcium boride, 0.1-1 parts of boron carbide, 1-5 parts of phenolic resin and 0.1-1 parts of urotropine, the oxidation resistance of the magnesia-carbon brick is improved by adding calcium boride, the oxidation of carbon is prevented, and the further densification of the organizational structure is promoted, so that the high-temperature bending strength, oxidation resistance and erosion resistance of the magnesia-carbon brick are greatly improved; the traditional phenolic resin is used as a binder in the above patents, and the high-temperature resistance and oxidation resistance of the phenolic resin are not ideal. SUMMARY

[0004] The present application aims at the deficiencies of the prior art, and provides a high-strength erosion-resistant low-carbon magnesia-carbon brick and a preparation method thereof, in which the fused magnesia particles and the fused magnesia fine powder with good high-temperature resistance and slag erosion resistance are used as main components, and the modified phenolic resin with multiple functions is used as a binder to firmly combine the raw material components together, so that the low-carbon magnesia-carbon brick with good high-temperature strength, oxidation resistance and erosion resistance is prepared, and the service life of the low-carbon magnesia-carbon brick is prolonged.

[0005] The technical scheme adopted by the present application to achieve the above-mentioned purpose is:

[0006] A high-strength erosion-resistant low-carbon magnesium-carbon brick comprises the following components in parts by weight: 60-70 parts of fused magnesium sand particles; 15-20 parts of fused magnesium sand fine powder; 1-3 parts of flake graphite; 3-5 parts of antioxidant; 2-4 parts of modified phenolic resin.

[0007] Further, the particle size of the fused magnesium sand particles is 1-5 mm, and the magnesium oxide content is ≥98 wt%; the particle size of the fused magnesium sand fine powder is ≤0.088 mm, and the magnesium oxide content is ≥98 wt%; the particle size of the flake graphite is ≤0.15 mm; the antioxidant is any one or a mixture of several of aluminum powder, silicon powder, zinc powder, boron carbide, zirconium boride, and magnesium-aluminum alloy.

[0008] Further, the preparation method of the modified phenolic resin is as follows: phenol, formaldehyde, and a catalyst are added into a reaction container, the temperature is raised to 80-90 DEG C, and reaction is carried out for 1-2 h; a composite modifier is added, and reaction is continued for 1-2 h; propylene glycol is added, and stirred uniformly; vacuum dehydration is carried out to obtain the modified phenolic resin; the mass ratio of the phenol, formaldehyde, catalyst, composite modifier, and propylene glycol is 1:1.2-1.5:0.02-0.05:0.2-0.4:0.02-0.04; and the catalyst is any one or a mixture of several of sodium hydroxide, calcium hydroxide, barium hydroxide, and sodium carbonate.

[0009] Further, the preparation method of the composite modifier is as follows: a modifier, triethylamine, and modified alumina are added into ethanol, and stirred uniformly; the temperature is raised to 60-70 DEG C, and reaction is carried out for 2-4 h to obtain the composite modifier; the mass ratio of the modifier, modified alumina, and triethylamine is 1:0.8-1:0.4-0.5; and the chemical structural formula of the modifier is as follows:

[0010]

[0011] Further, the preparation method of the modified phenolic resin is as follows:

[0012] S1, p-nitrophenethyl alcohol and sodium hydroxide are added into N, N-dimethylformamide, and epoxy chloropropane is added dropwise under stirring; after dropping, the temperature is raised to 80-90 DEG C, and reaction is carried out for 2-4 h to obtain compound 1, and the structural formula is as follows:

[0013] The molar ratio of the p-nitrophenethyl alcohol, epoxy chloropropane, and sodium hydroxide is 1:1.1-1.2:1.5-2.0;

[0014] S2, compound 1, triethylamine are added to anhydrous ether, diethyl chlorophosphite is added dropwise under ice bath condition, after dropping, the reaction is continued for 1-2h to obtain compound 2, the structural formula is:

[0015] The molar ratio of the compound 1, diethyl chlorophosphite, triethylamine is 1:1.1-1.2:1.5-2.0.

[0016] S3, compound 2, palladium-carbon are added to methanol, 0.1MPa hydrogen is introduced, and the reaction is carried out at room temperature for 6-8h to obtain a modifier; the mass ratio of the compound 2, palladium-carbon is 1:0.1-0.15.

[0017] Further, the preparation method of the modified alumina is as follows: alumina is added to toluene, 3-aminopropyl triethoxysilane is added dropwise after stirring for 20-30min, the reaction is carried out under reflux for 10-12h under nitrogen protection to obtain modified alumina; the mass ratio of the alumina, 3-aminopropyl triethoxysilane is 1:0.3-0.5.

[0018] The application provides a preparation method of high-strength erosion-resistant low-carbon magnesia carbon brick, which comprises the following steps: according to component allocation ratio, electric smelting magnesia particles, electric smelting magnesia fine powder, flaky graphite, antioxidant and modified phenolic resin are added into a mixing machine and mixed for 30-40min, then are put into a mold for compression molding, and the low-carbon magnesia carbon brick is obtained after baking; the molding pressure is 120-150Mpa, the baking temperature is 200-250 DEG C, and the baking time is 15-20h.

[0019] The application has the following beneficial effects:

[0020] The composite modifier prepared in the application is an aniline composite modifier, contains rigid benzene ring groups, phosphite groups and alumina connected through silane chemical bonds in the molecule, the aniline groups in the composite modifier participate in the polycondensation reaction of phenol and formaldehyde under the action of an alkaline catalyst, the modification of the phenolic resin is successfully realized, the modified phenolic resin obtained contains benzene ring groups, phosphite groups and alumina connected through chemical bonds in the molecular chain, the rigid benzene ring groups can improve the high-temperature stability and strength of the phenolic resin, the phosphite groups have good high-temperature resistance and can also play an auxiliary antioxidant role, the alumina connected through chemical bonds also has the characteristics of good high-temperature resistance, antioxidant property and erosion resistance, and can greatly improve the high-temperature resistance, antioxidant property and erosion resistance of the phenolic resin, the modified phenolic resin with good high-temperature resistance, antioxidant property and erosion resistance is added to the low-carbon magnesia carbon brick, especially the alumina grafted by the modified phenolic resin, compared with the direct addition of alumina, the former is combined with other components more firmly, so that the high-temperature strength, antioxidant property and erosion resistance of the low-carbon magnesia carbon brick are improved.

[0021] This invention uses fused magnesia particles and fine fused magnesia powder with good high temperature resistance and slag erosion resistance as the main components, and uses modified phenolic resin with multiple functions as a binder to firmly combine the raw material components together, thus preparing low carbon magnesia-carbon bricks with good high temperature strength, oxidation resistance and erosion resistance, which helps to extend the service life of low carbon magnesia-carbon bricks. Detailed Implementation

[0022] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] Phenol CAS No. 108-95-2; Formaldehyde CAS No. 50-00-0; Sodium hydroxide CAS No. 1310-73-2; Calcium hydroxide CAS No. 1305-62-0; Barium hydroxide CAS No. 17194-00-2; Sodium carbonate CAS No. 497-19-8; Alumina CAS No. 1344-28-1; Boron carbide CAS No. 12069-32-8; p-Nitrophenylethanol CAS No. 100-27-6; Epichlorohydrin CAS No. 106-89-8; Diethylphosphorous chloride CAS No. 589-5 7-1; Triethylamine CAS No. 121-44-8; Palladium on carbon CAS No. 7440-05-3; 3-Aminopropyltrimethoxysilane CAS No. 13822-56-5; Propylene glycol CAS No. 57-55-6; Diethyl ether CAS No. 60-29-7; Ethanol CAS No. 64-17-5; Toluene CAS No. 108-88-3; Dichloromethane CAS No. 75-09-2; Methanol CAS No. 67-56-1; N,N-Dimethylformamide CAS No. 68-12-2; All chemical reagents are commercially available.

[0024] Example 1

[0025] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 70 parts fused magnesia particles; 20 parts fused magnesia fine powder; 3 parts flake graphite; 5 parts antioxidant; and 4 parts modified phenolic resin.

[0026] The fused magnesia particles have a particle size of 3-5 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.088 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.15 mm; and the antioxidant is aluminum powder.

[0027] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 40 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 150 MPa, the baking temperature is 200℃, and the baking time is 20 h.

[0028] The modified phenolic resin is prepared by adding phenol, formaldehyde, and sodium hydroxide into a reaction vessel, heating to 80°C, reacting for 2 hours, adding a composite modifier, continuing the reaction for 2 hours, adding propylene glycol, stirring evenly, and vacuum dehydrating to obtain the modified phenolic resin; the mass ratio of phenol, formaldehyde, sodium hydroxide, composite modifier, and propylene glycol is 1:1.5:0.05:0.4:0.04.

[0029] The preparation method of the composite modifier is as follows: the modifier and triethylamine are added to ethanol, modified alumina is added, the mixture is stirred evenly, heated to 70℃, and reacted for 4 hours. After the reaction is completed, the mixture is allowed to cool naturally to room temperature, filtered, and the filter residue is washed with ethanol and water in sequence, and dried to obtain the composite modifier. The mass ratio of the modifier, modified alumina and triethylamine is 1:1:0.5, and the amount of ethanol used is 15 times the mass of the modifier.

[0030] The modified alumina was prepared by adding alumina to toluene and stirring for 30 minutes. Then, 3-aminopropyltriethoxysilane was added dropwise. The mixture was refluxed for 12 hours under nitrogen protection. After the reaction was completed, the mixture was allowed to cool to room temperature naturally and then filtered. The filter residue was washed with toluene and water in sequence and dried to obtain the modified alumina. The mass ratio of alumina to 3-aminopropyltriethoxysilane was 1:0.3-0.5, and the amount of toluene used was 15 times the mass of alumina.

[0031] The preparation method of the modifier is as follows:

[0032] S1. 35.0 g of p-nitrobenzeneethanol and 12.6 g of sodium hydroxide were added to 800 mL of N,N-dimethylformamide. 21.3 g of epichlorohydrin was added dropwise with stirring. After the addition was complete, the temperature was raised to 80 °C, and the reaction was allowed to proceed for 4 h. After the reaction was complete, 800 mL of water and 1600 mL of dichloromethane were added for extraction. The organic phase was collected, dried, and concentrated under reduced pressure to obtain 45.6 g of compound 1. The molar ratio of p-nitrobenzeneethanol, epichlorohydrin, and sodium hydroxide was 1:1.1:1.5. The reaction process was as follows:

[0033]

[0034] Compound 1: ESI (m / z): 260.1 [M+H] + , 1H-NMR (600MHz, DMSO-d6, δppm): 8.14 (d, J=8.6Hz, 2H), 7.52 (d, J=8.6Hz, 2H), 5.37 (s , 1H), 4.11-4.13 (m, 1H), 3.64-3.70 (m, 4H), 3.38-3.40 (m, 2H), 2.85 (t, J=7.2Hz, 2H).

[0035] S2. 26.0 g of compound 1 and 15.2 g of triethylamine were added to 500 mL of anhydrous diethyl ether. Under ice bath conditions, 17.3 g of diethylphosphorous chloride was added dropwise. After the addition was complete, the reaction was continued for 2 h. After the reaction was completed, the anhydrous diethyl ether was removed, and 500 mL of water and 500 mL of dichloromethane were added for extraction. The organic phase was collected, dried, and concentrated under reduced pressure to obtain 33.5 g of compound 2. The molar ratio of compound 1, diethylphosphorous chloride, and triethylamine was 1:1.1:1.5. The reaction process was as follows:

[0036]

[0037] S3. Add 20.0 g of compound 2 and 2.0 g of palladium on carbon to 500 mL of methanol, purge with 0.1 MPa hydrogen gas, and react at room temperature for 8 h. After the reaction is complete, filter off the palladium on carbon, wash with methanol, and concentrate the filtrate under reduced pressure to obtain 15.2 g of modifier. The mass ratio of compound 2 to palladium on carbon is 1:0.1. The reaction process is as follows:

[0038]

[0039] Modifier: ESI (m / z): 350.1 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 6.92 (d, J=8.6Hz, 2H), 6.45 (d, J=8.6Hz, 2H), 4.91 (s, 2H), 4.11-4.12 (m, 1 H), 3.86-3.88 (m, 4H), 3.63-3.66 (m, 4H), 3.39-3.41 (m, 2H), 2.73 (t, J=7.4Hz, 2H), 1.26 (t, J=7.6Hz, 6H).

[0040] Example 2

[0041] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 60 parts fused magnesia particles; 15 parts fused magnesia fine powder; 1 part flake graphite; 3 parts antioxidant; and 2 parts modified phenolic resin.

[0042] The fused magnesia particles have a particle size of 1-3 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.074 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.125 mm; and the antioxidant is boron carbide.

[0043] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 30 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 120 MPa, the baking temperature is 250℃, and the baking time is 15 h.

[0044] The modified phenolic resin was prepared as follows: phenol, formaldehyde, and sodium hydroxide were added to a reaction vessel, heated to 90°C, and reacted for 1.5 hours. A composite modifier was added, and the reaction continued for another 1.5 hours. Propylene glycol was added, stirred evenly, and then vacuum dehydrated to obtain the modified phenolic resin. The mass ratio of phenol, formaldehyde, sodium hydroxide, composite modifier, and propylene glycol was 1:1.2:0.02:0.2:0.02. The preparation method of the composite modifier was the same as in Example 1.

[0045] Example 3

[0046] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 65 parts fused magnesia particles; 18 parts fused magnesia fine powder; 2 parts flake graphite; 4 parts antioxidant; and 3 parts modified phenolic resin.

[0047] The fused magnesia particles have a particle size of 1-3 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.065 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.1 mm; and the antioxidant is zinc powder.

[0048] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 35 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 140 MPa, the baking temperature is 230℃, and the baking time is 18 hours.

[0049] The preparation method of the modified phenolic resin is the same as that in Example 1.

[0050] Example 4

[0051] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 70 parts fused magnesia particles; 15 parts fused magnesia fine powder; 1 part flake graphite; 4 parts antioxidant; and 4 parts modified phenolic resin.

[0052] The fused magnesia particles have a particle size of 3-5 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.05 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.15 mm; and the antioxidant is silicon powder.

[0053] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 40 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 120 MPa, the baking temperature is 250℃, and the baking time is 20 h.

[0054] The preparation method of the modified phenolic resin is the same as that in Example 2.

[0055] Comparative Example 1

[0056] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 70 parts fused magnesia particles; 20 parts fused magnesia fine powder; 3 parts flake graphite; 5 parts antioxidant; and 4 parts modified phenolic resin.

[0057] The fused magnesia particles have a particle size of 3-5 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.088 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.15 mm; and the antioxidant is aluminum powder.

[0058] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 40 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 150 MPa, the baking temperature is 200℃, and the baking time is 20 h.

[0059] The modified phenolic resin was prepared as follows: phenol, formaldehyde, and sodium hydroxide were added to a reaction vessel, heated to 80°C, and reacted for 2 hours. A modifier was added, and the reaction continued for another 2 hours. Propylene glycol was added, stirred until homogeneous, and then dehydrated under vacuum to obtain the modified phenolic resin. The mass ratio of phenol, formaldehyde, sodium hydroxide, modifier, and propylene glycol was 1:1.5:0.05:0.4:0.04. The preparation method of the modifier was the same as in Example 1.

[0060] Comparative Example 2

[0061] A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick comprises the following components by weight: 70 parts fused magnesia particles; 20 parts fused magnesia fine powder; 3 parts flake graphite; 5 parts antioxidant; and 4 parts phenolic resin.

[0062] The fused magnesia particles have a particle size of 3-5 mm and a magnesium oxide content of ≥98 wt%; the fine fused magnesia powder has a particle size of 0.088 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of 0.15 mm; and the antioxidant is aluminum powder.

[0063] A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick includes the following steps: according to the component ratio, fused magnesia particles, fused magnesia fine powder, flake graphite, antioxidant, and phenolic resin are added to a mixer and mixed for 40 minutes, then placed in a mold and pressed into shape, and baked to obtain a low-carbon magnesia-carbon brick; the molding pressure is 150 MPa, the baking temperature is 200℃, and the baking time is 20 h.

[0064] Related tests

[0065] The low-carbon magnesia-carbon bricks prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance tests. The bulk density and apparent porosity were tested according to GB / T 2997-2000 standard; the room temperature compressive strength was tested according to GB / T 5072.2-2004 standard; the high temperature flexural strength was tested according to GB / T 3002-2004 standard; and the linear expansion rate was tested according to GB / T Standard 7320.1-2000; Antioxidant test: Low-carbon magnesia-carbon bricks were made into samples of 25mm×25mm×150mm, heated to 1500℃ and held for 30min, then removed, cooled and cut open, and the thickness of the decarburized layer on the cross-section was measured to evaluate the antioxidant properties of the samples; Erosion resistance test: Low-carbon magnesia-carbon bricks were made into crucible samples with dimensions of φ50mm×50mm and inner hole dimensions of φ22mm×18mm. The static erosion resistance test method was adopted. 20g of ladle slag was filled into the crucible sample, placed in a carbon-buried atmosphere, and held at 1500℃ for 3h. After cooling with the furnace, the crucible was cut open along the height direction, and the penetration area S of the central cross-section of the crucible was measured. The erosion index S / S0×100% (S0 is the cross-sectional area of ​​the original crucible central hole) was calculated to evaluate the erosion resistance of the samples; The test results are shown in Table 1.

[0066] Table 1. Test results of various properties of low-carbon magnesia-carbon bricks

[0067]

[0068] As shown in Table 1, the low-carbon magnesia-carbon bricks prepared in Examples 1-4 exhibit superior comprehensive performance. Compared with Comparative Example 1 (modified phenolic resin without alumina) and Comparative Example 2 (ordinary phenolic resin), the modified phenolic resin added in Example 1 contains benzene ring groups, phosphite groups, and alumina linked by chemical bonds on its molecular chain. The rigid benzene ring groups can improve the high-temperature stability and strength of the phenolic resin, while the phosphite groups have good high-temperature resistance and can also play an auxiliary role in anti-oxidation. The alumina linked by chemical bonds also has the characteristics of good high-temperature resistance, oxidation resistance, and erosion resistance, which can greatly improve the high-temperature resistance, oxidation resistance, and erosion resistance of the phenolic resin, thereby improving the high-temperature strength, oxidation resistance, and erosion resistance of the low-carbon magnesia-carbon bricks and helping to extend the service life of the low-carbon magnesia-carbon bricks.

[0069] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-strength, corrosion-resistant, low-carbon magnesia-carbon brick, characterized in that, It includes the following components by weight: 60-70 parts fused magnesia granules; 15-20 parts fused magnesia fine powder; 1-3 parts flake graphite; 3-5 parts antioxidant; 2-4 parts modified phenolic resin; The modified phenolic resin is prepared by adding phenol, formaldehyde, and catalyst into a reaction vessel, heating to 80-90℃, reacting for 1-2 hours, adding a composite modifier, continuing the reaction for 1-2 hours, adding propylene glycol, stirring evenly, and vacuum dehydrating to obtain the modified phenolic resin; the mass ratio of phenol, formaldehyde, catalyst, composite modifier, and propylene glycol is 1:1.2-1.5:0.02-0.05:0.2-0.4:0.02-0.04; the catalyst is any one or a mixture of sodium hydroxide, calcium hydroxide, barium hydroxide, and sodium carbonate; The preparation method of the composite modifier is as follows: The modifier and triethylamine are added to ethanol, modified alumina is added, the mixture is stirred until homogeneous, heated to 60-70℃, and reacted for 2-4 hours to obtain the composite modifier; the chemical structural formula of the modifier is: ； The mass ratio of the modifier, modified alumina, and triethylamine is 1:0.8-1:0.4-0.5; The modified alumina is prepared by adding alumina to toluene, stirring for 20-30 min, then adding 3-aminopropyltriethoxysilane dropwise, and refluxing for 10-12 h under nitrogen protection to obtain modified alumina; the mass ratio of alumina to 3-aminopropyltriethoxysilane is 1:0.3-0.

5.

2. The high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to claim 1, characterized in that, The method for preparing the modifier is as follows: S1. Add p-nitrobenzyl alcohol and sodium hydroxide to N,N-dimethylformamide, and add epichlorohydrin dropwise while stirring. After the addition is complete, raise the temperature to 80-90℃ and react for 2-4 hours to obtain compound 1, with the following structural formula: ； S2. Compound 1 and triethylamine were added to anhydrous diethyl ether. Under ice bath conditions, diethylphosphine chloride was added dropwise. After the addition was complete, the reaction was continued for 1-2 hours to obtain compound 2, with the following structural formula: ； S3. Add compound 2 and palladium on carbon to methanol, introduce hydrogen gas at 0.1 MPa, and react at room temperature for 6-8 hours to obtain the modifier.

3. The high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to claim 2, characterized in that, In step S1, the molar ratio of p-nitrophenylethanol, epichlorohydrin, and sodium hydroxide is 1:1.1-1.2:1.5-2.0; in step S2, the molar ratio of compound 1, diethylphosphorous chloride, and triethylamine is 1:1.1-1.2:1.5-2.0; and in step S3, the mass ratio of compound 2 and palladium on carbon is 1:0.1-0.

15.

4. The high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to claim 1, characterized in that, The fused magnesia particles have a particle size of 1-5 mm and a magnesium oxide content of ≥98 wt%; the fused magnesia fine powder has a particle size of ≤0.088 mm and a magnesium oxide content of ≥98 wt%; the flake graphite has a particle size of ≤0.15 mm.

5. The high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to claim 1, characterized in that, The antioxidant is any one or a mixture of several of the following: aluminum powder, silicon powder, zinc powder, boron carbide, zirconium boride, and magnesium-aluminum alloy.

6. A method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to any one of claims 1-5, characterized in that, The process includes the following steps: according to the group ratio, fused magnesia granules, fused magnesia fine powder, flake graphite, antioxidant, and modified phenolic resin are added to a mixer and mixed for 30-40 minutes. Then, the mixture is placed in a mold, pressed into shape, and baked to obtain low-carbon magnesia-carbon bricks.

7. The method for preparing a high-strength, corrosion-resistant, low-carbon magnesia-carbon brick according to claim 6, characterized in that, The molding pressure is 120-150 MPa, the baking temperature is 200-250℃, and the baking time is 15-20 hours.

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