Preparation method of magnesia-carbon refractory castable

Abstract

The invention relates to the technical field of refractory materials, and particularly discloses a preparation method of a magnesia-carbon refractory castable. The preparation method comprises the following steps: S1, adding silica and magnesia into normal octane, uniformly stirring, filtering and drying to obtain a reactant A; the preparation method comprises the following steps: sequentially adding a reactant A, an isocyanate compound and a catalyst into a mixed solvent, uniformly stirring, stirring at 50-55 DEG C for 3-5 hours, and evaporating to remove the solvent, so as to obtain modified magnesia; s2, taking the modified magnesia, carbon and glass beads, and uniformly stirring to obtain a dry material; and adding water into the dry material, uniformly stirring, curing, and baking to obtain the magnesia-carbon refractory castable. The reactant A comprises the following raw materials in parts by mass: 5-8 parts of a silica compound and 10-15 parts of magnesia; the modified magnesia is prepared from the following raw materials in parts by mass: 12 to 18 parts of reactant A and 2 to 4 parts of isocyanate compound.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and specifically discloses a method for preparing a magnesium-carbon refractory castable. Background Art

[0002] The production cycle of machine-pressed magnesium-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 rate.

[0003] Amorphous refractory castables are first made of a mixture of refractory aggregates and admixtures, which is then mixed with water to form a mud material that can be constructed by casting. It has strong adaptability and can be made into a solid integral structure. In the prior art, there are some problems with magnesium-carbon castables, such as poor dispersion of the introduced carbon and hydration of the magnesium sand raw material when it meets 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 method for preparing a magnesium-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 magnesium-carbon refractory castable to solve the problems raised in the prior art.

[0005] To achieve the above 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 reactant A, an isocyanate compound, and a catalyst to a mixed solvent in sequence, stirring evenly, stirring at 50 to 55° C. for 3 to 5 hours, and evaporating and removing the solvent to obtain a modified magnesium sand;

[0006] S2: Take modified magnesia sand, 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] Preferably, the reactant A comprises the following raw materials, 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 weight: 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 diphenyl dimethyl (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 weight: 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 into 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 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.

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

[0016] Preferably, 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 sand will undergo a hydration reaction when it meets water, resulting in a decrease in performance, so the magnesia sand 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 to increase the affinity between the two, and the hydroxyl group provides a reaction site for the next step of modification; in the next step of modification, dodecyl isocyanate is used The long alkyl chains of esters, tert-butyl isocyanate and dodecyl isocyanate have the effect of increasing flexibility and helping to improve fluidity. At the same time, carbonization at high temperature can form carbon bonds, which improves the strength and slag resistance of the castable. The presence of tert-butyl isocyanate enhances the steric hindrance effect and helps plasticization. The addition ratio of the two needs to be controlled: more dodecyl isocyanate and less tert-butyl isocyanate will lead to a decrease in plasticization 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 step of modification; the next step of modification is to introduce 2-(phosphoryloxy)ethyl acrylate and tetraallyl ammonium chloride; the introduction of phosphoryl structure provides steric hindrance effect and electrostatic repulsion effect, which helps to improve dispersibility; the introduction of tetraallyl ammonium chloride increases the branch structure and improves the density and mechanical properties of the castable; the addition amount of tetraallyl ammonium chloride should not be too much, because too much branch structure leads to excessive steric hindrance, which affects the modification effect and compatibility with other raw materials;

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

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0024] 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 it to 120 parts of water, stir evenly, add 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir and react at 78°C for 5 hours, remove the solvent, and 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 evenly to obtain dry material.

[0027] Example 2: S1: Take 0.2 parts of sodium oleate and dissolve it in 300 parts of water, introduce nitrogen, heat to 55°C, add 8 parts of graphite, keep warm for 15 minutes, evacuate, wash, and dry to obtain sodium oleate-modified graphite; take 10 parts of sodium oleate-modified graphite, add it to 120 parts of water, stir evenly, add 1 part of 2-(phosphoryloxy)ethyl acrylate, 0.1 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0030] Example 3: S1: Take 0.5 parts of sodium oleate and dissolve it in 300 parts of water, introduce nitrogen, heat to 55°C, add 12 parts of graphite, keep warm for 15 minutes, evacuate, wash, and dry to obtain sodium oleate-modified graphite; take 15 parts of sodium oleate-modified graphite, add it to 120 parts of water, stir evenly, add 2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.15 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir and react at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0033] Example 4: S1: Take 0.3 parts of sodium oleate and dissolve it in 300 parts of water, introduce nitrogen, heat to 50°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 it to 120 parts of water, stir evenly, add 2 parts of 2-(phosphoryloxy)ethyl acrylate, 0.1 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir and react at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0036] Example 5: S1: Take 0.5 parts of sodium oleate and dissolve it in 300 parts of water, introduce nitrogen, heat to 50°C, add 8 parts of graphite, keep warm for 15 minutes, evacuate, wash, and dry to obtain sodium oleate-modified graphite; take 10 parts of sodium oleate-modified graphite, add it to 120 parts of water, stir evenly, add 1 part of 2-(phosphoryloxy)ethyl acrylate, 0.15 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0039] Comparative Example 1 (changing the amount of each raw material added in 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, pass 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 it to 120 parts of water, stir evenly, add 1.5 parts of 2-(phosphoryloxy)ethyl acrylate, 0.2 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0042] Comparative Example 2 (changing the amount of each raw material added in 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, pass 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 it to 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, stir 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: Take 0.4 parts of sodium oleate and dissolve it in 300 parts of water, pass 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 it to 120 parts of water, stir evenly, add 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir the reaction at 78°C for 5 hours, remove the solvent, and 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, stir 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: Take 0.4 parts of sodium oleate and dissolve it in 300 parts of water, pass 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 it to 120 parts of water, stir evenly, add 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir the reaction at 78°C for 5 hours, remove the solvent, and 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, stir evenly to obtain dry material.

[0051] Comparative Example 5 (changing the particle size of magnesium sand, the remaining 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 it to 120 parts of water, stir evenly, add 1.8 parts of 2-(phosphoryloxy)ethyl acrylate, 0.12 parts of tetraallyl ammonium chloride, and 0.01 parts of benzoyl peroxide, stir at 78°C for 5 hours, remove the solvent, and 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, 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 3-5mm and 50wt% of magnesia with a particle size of 1-3mm;

[0053] S3: Take 95 parts of modified magnesia, 12 parts of carbon, and 7 parts of glass beads, stir 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 sources of the raw materials are as follows: sodium oleate (CAS: 143-19-1); polydimethylsiloxane (T22990, Shanghai Yuanye); hydroxy-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 microspheres (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 casting material, stir evenly, vibrate and shape in a mold, bake at 110°C for 24h after curing, and test the compressive strength according to the reference standard GB / T 5072-2008; (2) re-fire at 1550°C for 3h, and test the compressive strength again; see the table below for specific data;

[0056]

[0057]

[0058] Conclusion: Comparative Example 1 changes the amount of each raw material added in the carbon, 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 the performance; Comparative Example 2 does not add tetraallyl ammonium chloride, and the performance is significantly reduced, from which it can be seen that the importance of each raw material in the carbon; Comparative Example 3 and Comparative Example 4 change the amount of dodecyl isocyanate and tert-butyl isocyanate added in the modified magnesia, 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; Comparative Example 5 changes the particle size of the magnesia, 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a magnesium-carbon refractory castable, characterized in that: The following steps are involved: 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 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 and removing the solvent to obtain modified magnesia; S2: Take modified magnesia sand, carbon and glass beads, stir them evenly to obtain dry material; add water to the dry material and stir it evenly, cure and bake to obtain magnesia-carbon refractory castable.

2. The method for preparing a magnesium-carbon refractory castable according to claim 1, characterized in that: 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 weight: 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 2, characterized in that: The silicon oxide compound comprises polydimethylsiloxane and hydroxyl-terminated diphenyl dimethyl (siloxane and polysiloxane) in a mass ratio of (1-2): (4-6).

4. The method for preparing a magnesium-carbon refractory castable according to claim 2, characterized in that: The isocyanate compound includes dodecyl isocyanate and tert-butyl isocyanate in a mass ratio of (1.5-2):(1-1.5).

5. The method for preparing a magnesium-carbon refractory castable according to claim 1, characterized in that: The dry material comprises 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 microspheres.

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

7. The method for preparing a magnesium-carbon refractory castable according to claim 1, characterized in that: 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, evacuating, washing and drying to obtain sodium oleate modified graphite; Step 2: Take sodium oleate-modified graphite and add it into 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.

8. The method for preparing a magnesium-carbon refractory castable according to claim 7, characterized in that: The sodium oleate modified graphite includes the following raw materials, calculated by weight: 0.2-0.5 parts of sodium oleate and 8-12 parts of graphite; the carbon includes the following raw materials, calculated by weight: 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.

9. 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.

Images