A method for preparing magnesium carbon refractory castable

Abstract

The present invention relates to the technical field of refractory materials, and specifically discloses a method for preparing a magnesium-carbon refractory castable. The preparation method comprises the following steps: S1: adding a silicon oxide compound and magnesia to n-octane, stirring evenly, filtering, and drying to obtain a reactant A; sequentially adding reactant A, an isocyanate compound, and a catalyst to a mixed solvent, stirring evenly, stirring at 50-55°C for 3-5 hours, and evaporating and removing the solvent to obtain modified magnesia; S2: taking modified magnesia, carbon, and glass microbeads, stirring evenly to obtain a dry material; adding water to the dry material, stirring evenly, curing, and baking to obtain the magnesium-carbon refractory castable. Reactant A comprises the following raw materials, calculated by weight: 5-8 parts of silicon oxide compound and 10-15 parts of magnesia; and modified magnesia comprises the following raw materials, calculated by weight: 12-18 parts of reactant A and 2-4 parts of isocyanate compound.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and particularly discloses a preparation method of a magnesia-carbon refractory castable. Background Art

[0002] The production cycle of machine-pressed magnesia-carbon refractory materials is long and the production cost is high. Compared with shaped refractory materials, amorphous refractory materials represented by refractory castables have the characteristics of short production cycle, low production cost, simple preparation process and high yield.

[0003] Unshaped refractory castables are first composed of a mixture of refractory aggregates and admixtures, which is then mixed with water to form a mud material that can be constructed by pouring. It has strong adaptability and can be made into a solid integral structure. In the existing technology, magnesia-carbon castables have some problems, such as poor dispersion of the introduced carbon and hydration of magnesia sand raw materials when they come into contact with water, which leads to defects in the internal structure and affects the mechanical properties of the castable. Therefore, it is of great significance to study a preparation method for a magnesia-carbon refractory castable with excellent performance. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a magnesia-carbon refractory castable to solve the problems raised in the prior art.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: A method for preparing a magnesium-carbon refractory castable, comprising the following steps: S1: (1) adding a silicon oxide compound and magnesium sand to n-octane, stirring evenly, filtering, and drying to obtain a reactant A; (2) adding the reactant A, an isocyanate compound, and a catalyst to a mixed solvent in sequence, stirring evenly, stirring at 50-55° C. for 3-5 hours, and evaporating and removing the solvent to obtain a modified magnesium sand;

[0006] S2: Take modified magnesia, carbon and glass beads, stir them evenly to obtain dry material; add water to the dry material, stir it evenly, cure and bake it to obtain magnesia-carbon refractory castable.

[0007] More optimally, the reactant A comprises the following raw materials, calculated by weight: 5 to 8 parts of silicon oxide, 90 to 100 parts of n-octane, and 10 to 15 parts of magnesia;

[0008] The modified magnesia comprises the following raw materials, calculated by mass: 12 to 18 parts of reactant A, 2 to 4 parts of isocyanate compound, and 0.001 to 0.0015 parts of catalyst.

[0009] More optimally, the silicon oxide compound comprises polydimethylsiloxane and hydroxyl-terminated diphenyldimethyl (siloxane and polysiloxane) in a mass ratio of (1-2): (4-6).

[0010] More optimally, the isocyanate compound comprises dodecyl isocyanate and tert-butyl isocyanate in a mass ratio of (1.5-2): (1-1.5).

[0011] More optimally, the dry material includes the following raw materials, calculated by mass: 90 to 100 parts of modified magnesia, 8 to 15 parts of carbon, and 5 to 8 parts of glass beads.

[0012] More optimally, the carbon preparation process comprises the following steps: Step 1: dissolving sodium oleate in water, stirring to dissolve, introducing nitrogen, heating to 45-55° C., adding graphite, keeping warm for 10-20 minutes, vacuuming, washing, and drying to obtain sodium oleate-modified graphite;

[0013] Step 2: Take sodium oleate-modified graphite and add it to water, stir evenly, add 2-(phosphoryloxy)ethyl acrylate, tetraallyl ammonium chloride, and initiator, stir and react at 70-80°C for 4-6 hours, remove the solvent, and obtain carbon.

[0014] More optimally, the sodium oleate-modified graphite includes the following raw materials, calculated in parts by mass: 0.2 to 0.5 parts of sodium oleate and 8 to 12 parts of graphite; the carbon includes the following raw materials, calculated in parts by mass: 10 to 15 parts of sodium oleate-modified graphite, 1 to 2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.1 to 0.15 parts of tetraallylammonium chloride, and 0.01 to 0.015 parts of initiator.

[0015] More optimally, the magnesia includes 20-30 wt% of magnesia with a particle size of 3-5 mm, 30-50 wt% of magnesia with a particle size of 1-3 mm, and 30-50 wt% of magnesia with a particle size of 0-1 mm.

[0016] More optimally, the glass microbeads are 40-60 mesh glass microbeads.

[0017] More optimally, the graphite is flake graphite with a mesh size of 250 to 400.

[0018] More optimally, in the magnesium-carbon refractory castable, the amount of water added is 4% of the total mass of the magnesium-carbon refractory castable; water is added to the dry material and stirred evenly, poured into a mold, and baked at 110°C for 24 hours after curing to obtain the magnesium-carbon refractory castable.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: magnesia will undergo a hydration reaction when it comes into contact with water, resulting in a decrease in performance, so the magnesia is modified: first, polydimethylsiloxane and hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane) are coated on its surface to prevent water from penetrating; in the hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), the phenyl group and the subsequently added carbon produce a π-π stacking effect, thereby increasing the affinity between the two, and the hydroxyl group provides a reaction site for the next modification; in the next modification, dodecyl isocyanate is used. The long alkyl chains of esters, tert-butyl isocyanate, and dodecyl isocyanate increase flexibility and help improve fluidity. At the same time, carbonization at high temperatures can form carbon bonds, improving the strength and slag resistance of the castable. The presence of tert-butyl isocyanate enhances the steric hindrance effect and helps plasticize. The addition ratio of the two needs to be controlled: more dodecyl isocyanate and less tert-butyl isocyanate will lead to a decrease in plasticizing effect, while less dodecyl isocyanate and more tert-butyl isocyanate will lead to poor fluidity and poor compatibility with other raw materials.

[0020] Carbon has poor wettability with water, so it is first modified with sodium oleate to improve its wettability with water and introduce double bonds that can participate in the next modification. The next modification introduces 2-(phosphoryloxy)ethyl acrylate and tetraallyl ammonium chloride. The introduction of the phosphoryl structure provides steric hindrance and electrostatic repulsion effects, which helps improve dispersibility. The introduction of tetraallyl ammonium chloride increases the branching structure and improves the density and mechanical properties of the castable. The amount of tetraallyl ammonium chloride added should not be too much, as excessive branching leads to excessive steric hindrance, affecting the modification effect and compatibility with other raw materials.

[0021] The magnesia used in the present invention comprises 20-30 wt% of magnesia with a particle size of 3-5 mm, 30-50 wt% of magnesia with a particle size of 1-3 mm, and 30-50 wt% of magnesia with a particle size of 0-1 mm. Glass microbeads with a size of 40-60 meshes are used to reduce friction between the raw materials, destroy flocculation structure, and improve fluidity and uniformity. The graphite is flake graphite with a size of 250-400 meshes. The above raw materials form a particle size gradient, enhance fluidity, reduce the generation of bubbles and defects, and optimize the volume density of the castable, thereby improving its compressive strength, thermal shock resistance, erosion resistance and other properties. DETAILED DESCRIPTION

[0022] 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.

[0023] The following parts are by mass unless otherwise specified;

[0024] Example 1: S1: 0.4 parts of sodium oleate were dissolved in 300 parts of water, nitrogen was introduced, and the mixture was heated to 55°C. 10 parts of graphite were added, and the mixture was kept warm for 15 minutes. The mixture was evacuated, washed, and dried to obtain sodium oleate-modified graphite. 12 parts of sodium oleate-modified graphite were added to 120 parts of water and stirred uniformly. 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide were added. The mixture was stirred at 78°C for 5 hours, and the solvent was removed to obtain carbon.

[0025] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.8 parts of dodecyl isocyanate, 1.2 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 25wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 35wt% of magnesia with a particle size of 0-1mm;

[0026] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, stir them evenly to obtain dry material.

[0027] Example 2: S1: 0.2 parts of sodium oleate were dissolved in 300 parts of water, nitrogen was introduced, and the mixture was heated to 55°C. 8 parts of graphite were added, and the mixture was kept warm for 15 minutes. The mixture was evacuated, washed, and dried to obtain sodium oleate-modified graphite. 10 parts of sodium oleate-modified graphite were added to 120 parts of water and stirred evenly. 1 part of 2-(phosphoryloxy)ethyl acrylate, 0.1 part of tetraallylammonium chloride, and 0.01 part of benzoyl peroxide were added. The mixture was stirred at 78°C for 5 hours, and the solvent was removed to obtain carbon.

[0028] S2: Take 2 parts of polydimethylsiloxane, 4 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 10 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 12 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.5 parts of dodecyl isocyanate, 1 part of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 20wt% of magnesia with a particle size of 3-5mm, 50wt% of magnesia with a particle size of 1-3mm, and 30wt% of magnesia with a particle size of 0-1mm;

[0029] S3: Take 90 parts of modified magnesia, 8 parts of carbon, and 5 parts of glass beads, mix them evenly to obtain dry material.

[0030] Example 3: S1: 0.5 parts of sodium oleate was dissolved in 300 parts of water, nitrogen was introduced, and the mixture was heated to 55°C. 12 parts of graphite was added, and the mixture was kept warm for 15 minutes. The mixture was evacuated, washed, and dried to obtain sodium oleate-modified graphite. 15 parts of sodium oleate-modified graphite was added to 120 parts of water and stirred evenly. 2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.15 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide were added. The mixture was stirred at 78°C for 5 hours, and the solvent was removed to obtain carbon.

[0031] S2: Take 2 parts of polydimethylsiloxane, 6 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 15 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 18 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 2 parts of dodecyl isocyanate, 1.5 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 30wt% of magnesia with a particle size of 3-5mm, 30wt% of magnesia with a particle size of 1-3mm, and 40wt% of magnesia with a particle size of 0-1mm;

[0032] S3: Take 100 parts of modified magnesia, 15 parts of carbon, and 8 parts of glass beads, mix them evenly to obtain dry material.

[0033] Example 4: S1: 0.3 parts of sodium oleate was dissolved in 300 parts of water, nitrogen was introduced, and the mixture was heated to 50°C. 10 parts of graphite was added, and the mixture was kept warm for 15 minutes. The mixture was evacuated, washed, and dried to obtain sodium oleate-modified graphite. 12 parts of sodium oleate-modified graphite was added to 120 parts of water and stirred evenly. 2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.1 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide were added. The mixture was stirred at 78°C for 5 hours, and the solvent was removed to obtain carbon.

[0034] S2: Take 1 part of polydimethylsiloxane, 6 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 12 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.5 parts of dodecyl isocyanate, 1.5 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 20wt% of magnesia with a particle size of 3-5mm, 50wt% of magnesia with a particle size of 1-3mm, and 30wt% of magnesia with a particle size of 0-1mm;

[0035] S3: Take 100 parts of modified magnesia, 15 parts of carbon, and 8 parts of glass beads, mix them evenly to obtain dry material.

[0036] Example 5: S1: 0.5 parts of sodium oleate were dissolved in 300 parts of water, nitrogen was introduced, and the mixture was heated to 50°C. 8 parts of graphite were added, and the mixture was kept warm for 15 minutes. The mixture was evacuated, washed, and dried to obtain sodium oleate-modified graphite. 10 parts of sodium oleate-modified graphite were added to 120 parts of water and stirred evenly. 1 part of 2-(phosphoryloxy)ethyl acrylate, 0.15 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide were added. The mixture was stirred at 78°C for 5 hours, and the solvent was removed to obtain carbon.

[0037] S2: Take 1 part of polydimethylsiloxane, 4 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 10 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 18 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 2 parts of dodecyl isocyanate, 1 part of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 30wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 30wt% of magnesia with a particle size of 0-1mm;

[0038] S3: Take 95 parts of modified magnesia, 8 parts of carbon, and 8 parts of glass beads, mix them evenly to obtain dry material.

[0039] Comparative Example 1 (changing the amount of each raw material added to the carbon, and the other method steps are consistent with Example 1): S1: 0.4 parts of sodium oleate are dissolved in 300 parts of water, nitrogen is introduced, and the mixture is heated to 55° C., 10 parts of graphite are added, and the mixture is kept warm for 15 minutes. The mixture is vacuumed, washed, and dried to obtain sodium oleate-modified graphite; 12 parts of sodium oleate-modified graphite are added to 120 parts of water, stirred evenly, and 1.5 parts of 2-(phosphoryloxy)ethyl acrylate, 0.2 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide are added. The mixture is stirred at 78° C. for 5 hours, and the solvent is removed to obtain carbon;

[0040] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.8 parts of dodecyl isocyanate, 1.2 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 25wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 35wt% of magnesia with a particle size of 0-1mm;

[0041] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, mix them evenly to obtain dry material.

[0042] Comparative Example 2 (changing the amount of each raw material added to the carbon, and the other method steps are consistent with Example 1): S1: Take 0.4 parts of sodium oleate and dissolve it in 300 parts of water, introduce nitrogen, heat to 55°C, add 10 parts of graphite, keep warm for 15 minutes, evacuate, wash, and dry to obtain sodium oleate-modified graphite; take 12 parts of sodium oleate-modified graphite, add 120 parts of water, stir evenly, add 1.8 parts of 2-(phosphoryloxy)ethyl acrylate and 0.01 parts of benzoyl peroxide, stir at 78°C for 5 hours, remove the solvent, and obtain carbon;

[0043] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.8 parts of dodecyl isocyanate, 1.2 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 25wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 35wt% of magnesia with a particle size of 0-1mm;

[0044] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, mix them evenly to obtain dry material.

[0045] Comparative Example 3 (changing the amount of each raw material added in the modified magnesia, and the other method steps are consistent with Example 1): S1: 0.4 parts of sodium oleate are dissolved in 300 parts of water, nitrogen is introduced, heated to 55 ° C, 10 parts of graphite are added, and the mixture is kept warm for 15 minutes. Vacuum, wash, and dry to obtain sodium oleate-modified graphite; 12 parts of sodium oleate-modified graphite are taken, added to 120 parts of water, stirred evenly, 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide are added, and the reaction is stirred at 78 ° C for 5 hours. The solvent is removed to obtain carbon;

[0046] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1 part of dodecyl isocyanate, 2 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 25wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 35wt% of magnesia with a particle size of 0-1mm;

[0047] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, mix them evenly to obtain dry material.

[0048] Comparative Example 4 (changing the amount of each raw material added in the modified magnesia, and the other method steps are consistent with Example 1): S1: 0.4 parts of sodium oleate are dissolved in 300 parts of water, nitrogen is introduced, heated to 55 ° C, 10 parts of graphite are added, and the mixture is kept warm for 15 minutes. Vacuum, wash, and dry to obtain sodium oleate-modified graphite; 12 parts of sodium oleate-modified graphite are taken, added to 120 parts of water, stirred evenly, 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide are added, and the reaction is stirred at 78 ° C for 5 hours. The solvent is removed to obtain carbon;

[0049] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 2.5 parts of dodecyl isocyanate, 0.5 parts of tert-butyl isocyanate, 0.001 parts of stannous octoate, stir at 55°C for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 25wt% of magnesia with a particle size of 3-5mm, 40wt% of magnesia with a particle size of 1-3mm, and 35wt% of magnesia with a particle size of 0-1mm;

[0050] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, mix them evenly to obtain dry material.

[0051] Comparative Example 5 (changing the particle size of magnesia, the remaining method steps are consistent with Example 1): S1: 0.4 parts of sodium oleate are dissolved in 300 parts of water, nitrogen is introduced, heated to 55 ° C, 10 parts of graphite are added, and the mixture is kept warm for 15 minutes. Vacuum, wash, and dry to obtain sodium oleate-modified graphite; 12 parts of sodium oleate-modified graphite are added to 120 parts of water, stirred evenly, 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide are added, and the reaction is stirred at 78 ° C for 5 hours. The solvent is removed to obtain carbon;

[0052] S2: Take 1 part of polydimethylsiloxane, 5 parts of hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane), 90 parts of n-octane, stir evenly, add 12 parts of magnesia, stir for 12 minutes, filter, and dry to obtain reactant A; take 14 parts of reactant A, add 90 parts of n-octane and 40 parts of acetone, stir evenly, add 1.8 parts of dodecyl isocyanate, 1.2 parts of tert-butyl isocyanate, and 0.001 parts of stannous octoate, stir at 55° C. for 4 hours, remove the solvent, and obtain modified magnesia; the magnesia includes 50wt% of magnesia with a particle size of 3 to 5mm and 50wt% of magnesia with a particle size of 1 to 3mm;

[0053] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, mix them evenly to obtain dry material.

[0054] In the above examples, the test methods used are conventional methods unless otherwise specified; the raw materials used are commercially available unless otherwise specified, and the raw material sources are as follows: sodium oleate (CAS: 143-19-1); polydimethylsiloxane (T22990, Shanghai Yuanye); hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane) (YK4795, Hubei Yongkuo Technology Co., Ltd.); n-octane (CAS: 111-65-9); acetone (CAS: 67-64-1); dodecyl isocyanate (CAS: 42 02-38-4); tert-butyl isocyanate (CAS: 1609-86-5); stannous octoate (CAS: 301-10-0); graphite (flake graphite, JK-R0806, 325 mesh, Shanghai Jingkang Bioengineering Co., Ltd.); glass microbeads (40-60 mesh, Xi'an Qiyue Biotechnology Co., Ltd.); 2-(phosphoryloxy)ethyl acrylate (CAS: 32120-16-4); tetraallylammonium chloride (CAS: 13107-10-3); benzoyl peroxide (CAS: 94-36-0).

[0055] Experiment: Take the dry materials prepared in Examples 1 to 3 and Comparative Examples 1 to 4; (1) add 4% water of the total mass of the castable, stir evenly, vibrate and shape in a mold, and after curing, bake at 110°C for 24 hours. Refer to the standard GB / T 5072-2008 and test the compressive strength; (2) re-fire at 1550°C for 3 hours and test the compressive strength again; the specific data are shown in the table below;

[0056]

[0057]

[0058] Conclusion: In comparative example 1, the amount of each raw material added in the carbon is changed, the amount of 2-(phosphoryloxy)ethyl acrylate added is reduced, and the amount of tetraallyl ammonium chloride added is increased, resulting in excessive branching structure, affecting performance; in comparative example 2, tetraallyl ammonium chloride is not added, and the performance is significantly reduced, from which it can be seen that the importance of each raw material in the carbon; in comparative example 3 and comparative example 4, the amount of dodecyl isocyanate and tert-butyl isocyanate added in the modified magnesia is changed, and the performance is not as good as the embodiment, from which it can be seen that controlling the amount of each raw material added in the modified magnesia is also of great significance; in comparative example 5, the particle size of the magnesia is changed, the particle size gradient is destroyed, and the performance is reduced; in summary, the castable prepared by the present invention has good mechanical properties.

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a magnesia-carbon refractory castable, characterized in that: The following steps are involved: S1: (1) adding a silicon oxide compound and magnesia to n-octane, stirring evenly, filtering, and drying to obtain reactant A; (2) adding reactant A, isocyanate compound, and catalyst to a mixed solvent in sequence, stirring evenly, stirring at 50-55° C. for 3-5 hours, and evaporating the solvent to obtain modified magnesia; S2: taking modified magnesia, carbon, and glass beads, stirring them evenly to obtain dry material; adding water to the dry material, stirring evenly, curing, and baking to obtain magnesia-carbon refractory castable; The silicone compound comprises polydimethylsiloxane and hydroxyl-terminated diphenyldimethyl (siloxane and polysiloxane) in a mass ratio of (1-2): (4-6); the isocyanate compound comprises dodecyl isocyanate and tert-butyl isocyanate in a mass ratio of (1.5-2): (1-1.5); The specific preparation process of the carbon The method comprises the following steps: step 1: dissolving sodium oleate in water, introducing nitrogen, heating to 45-55°C, adding graphite, keeping the temperature for 10-20 minutes, vacuuming, washing, and drying to obtain sodium oleate-modified graphite; step 2: adding the sodium oleate-modified graphite into water, stirring evenly, adding 2-(phosphoryloxy)ethyl acrylate, tetraallyl ammonium chloride, and an initiator, stirring and reacting at 70-80°C for 4-6 hours, and removing the solvent to obtain carbon.

2. The method for preparing a magnesium-carbon refractory castable according to claim 1, wherein: The reactant A comprises the following raw materials, calculated by weight: 5 to 8 parts of silicon oxide, 90 to 100 parts of n-octane, and 10 to 15 parts of magnesia; The modified magnesia comprises the following raw materials, calculated by mass: 12 to 18 parts of reactant A, 2 to 4 parts of isocyanate compound, and 0.001 to 0.0015 parts of catalyst.

3. The method for preparing a magnesium-carbon refractory castable according to claim 1, wherein: The dry material includes the following raw materials, calculated by weight: 90 to 100 parts of modified magnesia, 8 to 15 parts of carbon, and 5 to 8 parts of glass beads.

4. The method for preparing a magnesium-carbon refractory castable according to claim 1, wherein: The magnesia comprises 20-30 wt% of magnesia with a particle size of 3-5 mm, 30-50 wt% of magnesia with a particle size of 1-3 mm, and 30-50 wt% of magnesia with a particle size of 0-1 mm; the glass microbeads are 40-60 mesh glass microbeads.

5. The method for preparing a magnesium-carbon refractory castable according to claim 1, wherein: The sodium oleate-modified graphite includes the following raw materials, calculated by mass: 0.2-0.5 parts of sodium oleate and 8-12 parts of graphite; the carbon includes the following raw materials, calculated by mass: 10-15 parts of sodium oleate-modified graphite, 1-2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.1-0.15 parts of tetraallylammonium chloride, and 0.01-0.015 parts of initiator.

6. The method for preparing a magnesium-carbon refractory castable according to claim 1, characterized in that: In the magnesium-carbon refractory castable, the amount of water added is 3-5% of the total mass of the magnesium-carbon refractory castable.

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