Blast furnace trough refractory castable and preparation method thereof

Abstract

The application discloses a blast furnace iron runner refractory castable, which comprises a main material and an additive; the main material comprises raw materials in the following mass percentages: corundum 60-75%, silicon carbide 10-30%, alpha-Al2O3 micro powder 2-6%, SiO2 micro powder 1-5%, calcium aluminate cement 1-4%, elemental silicon powder 0.5-1%, and spherical pitch 0.5-1.5%; and the additive comprises modified carbon fibers and a water reducing agent. The application further discloses a preparation method of the blast furnace iron runner refractory castable. The blast furnace iron runner refractory castable has excellent high-temperature mechanical properties, thermal shock resistance and corrosion resistance, can effectively prolong the service life of the castable, and improve the cast iron production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refractory materials, and particularly relates to a refractory castable for a blast furnace iron runner and a preparation method thereof. BACKGROUND

[0002] The iron runner castable is a refractory material used for casting molten iron during blast furnace casting, and is used as the inner lining material of the iron runner. During casting, the molten iron and slag repeatedly flow through the iron runner, and are subjected to erosion by the molten iron, chemical corrosion by the slag, and frequent temperature fluctuations of rapid cooling and rapid heating. Therefore, the iron runner castable needs to have excellent corrosion resistance and thermal shock stability. With the progress of metallurgical technology, the temperature of the molten steel is increased, and the residence time is prolonged, and the working environment of the iron runner castable is deteriorating, and higher requirements are put forward for the performance of the iron runner castable. The Al2O3-SiC-C castable is a commonly used iron runner castable, which mainly comprises Al2O3 aggregate, SiC, carbon and additives. However, the high-temperature mechanical properties, thermal shock resistance and corrosion resistance of the ordinary Al2O3-SiC-C castable still have deficiencies, and the castable is easily cracked and peeled off due to the impact and corrosion of the frequent and large amount of high-temperature molten iron, thereby reducing the service life of the castable and affecting the production efficiency of the blast furnace casting. Therefore, it has become a hot spot in the field of refractory materials to comprehensively improve the high-temperature mechanical properties, thermal shock resistance and corrosion resistance of the Al2O3-SiC-C refractory castable for the blast furnace iron runner. SUMMARY

[0003] Based on the technical problems existing in the background art, the present application provides a refractory castable for a blast furnace iron runner and a preparation method thereof.

[0004] The refractory castable for the blast furnace iron runner provided by the present application comprises a main material and an additive.

[0005] The main material comprises raw materials in the following mass percentages: corundum 60-75%, silicon carbide 10-30%, alpha-Al2O3 micro powder 2-6%, SiO2 micro powder 1-5%, calcium aluminate cement 1-4%, elemental silicon powder 0.5-1%, and spherical pitch 0.5-1.5%, and the sum of the mass percentages of the above raw materials is 100%.

[0006] The additive comprises modified carbon fibers and a water reducing agent, wherein the amount of the modified carbon fibers is 0.4-0.8% of the mass of the main material, and the amount of the water reducing agent is 0.1-0.3% of the mass of the main material.

[0007] The preparation method of the modified carbon fibers comprises the following steps:

[0008] S1, placing carbon fibers in a mixed acid solution and performing heating oxidation treatment to obtain oxidized carbon fibers;

[0009] S2, the oxidized carbon fiber is added into a coating modification liquid for sufficient stirring, and then centrifuged and washed to obtain a coated carbon fiber; the coating modification liquid comprises the following components in mass percentage: 0.5-1% of silane coupling agent modified nano-TiO2, 0.5-0.8% of polydiallyldimethylammonium chloride, and the rest of water;

[0010] S3, the coated carbon fiber is added into a graphene oxide water dispersion liquid for sufficient stirring, and then centrifuged and washed, and heated and carbonized in an inert atmosphere to obtain the product.

[0011] Preferably, in S1, the mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1.

[0012] Preferably, in S1, the heating and oxidation treatment is performed at a temperature of 75-85℃ for 2-4h.

[0013] Preferably, in S2, the mass ratio of the oxidized carbon fiber to the coating modification liquid is 1:(5-10).

[0014] Preferably, in S2, the silane coupling agent modified nano-TiO2 is obtained by surface modification of nano-TiO2 with a silane coupling agent, and the silane coupling agent is silane coupling agent KH-540, KH-550 or a combination thereof; preferably, the mass ratio of the silane coupling agent to nano-TiO2 is (0.5-2):10.

[0015] In the present application, the method for surface modification of nano-TiO2 with a silane coupling agent is a conventional method in the art, for example, nano-TiO2 can be dispersed in deionized water to obtain a nano-TiO2 water dispersion liquid, and an ethanol solution of a silane coupling agent is added into the nano-TiO2 water dispersion liquid for sufficient stirring for 2-5h, and then centrifuged and dried to obtain the product.

[0016] Preferably, in S2, the stirring time is 5-10min.

[0017] Preferably, in S3, the ratio of the coated carbon fiber to the graphene oxide water dispersion liquid is 1g:(10-20)mL; and the concentration of the graphene oxide water dispersion liquid is 5-10mg / mL.

[0018] In the present application, the graphene oxide can be prepared by a conventional method, for example, by a conventional Hummers method.

[0019] Preferably, in S3, the stirring time is 5-10min.

[0020] Preferably, in S3, the heating and carbonization is performed at a temperature of 500-800℃ for 1-2h.

[0021] Preferably, the length of the carbon fiber is 1-10mm.

[0022] Preferably, the corundum is composed of corundum particles with a particle size less than 8mm and greater than or equal to 5mm, corundum particles with a particle size less than 5mm and greater than or equal to 3mm, corundum particles with a particle size less than 3mm and greater than or equal to 1mm, corundum particles with a particle size less than 1mm and greater than or equal to 0.088mm, and corundum fine powder with a particle size less than 0.088mm in a mass ratio of 1:(0.5-1):(0.5-1):(0.2-0.3):(0.2-0.3).

[0023] Preferably, the silicon carbide is composed of silicon carbide particles with a particle size less than 1mm and greater than or equal to 0.088mm, and silicon carbide fine powder with a particle size less than 0.088mm in a mass ratio of 1:(0.8-1.5).

[0024] Preferably, the particle size of the alpha-Al2O3 fine powder is 1-3um, and the particle size of the SiO2 fine powder is 1-3um.

[0025] Preferably, the water reducing agent is sodium tripolyphosphate, sodium hexametaphosphate, or a combination thereof.

[0026] A preparation method of the blast furnace trough refractory castable, comprising: uniformly mixing main materials of the castable, then adding an additive, and stirring uniformly to obtain the castable.

[0027] The beneficial effects of the present application are as follows:

[0028] The application first uses mixed acid to oxidize the surface of carbon fiber, then adds the coating modification liquid containing silane coupling agent modified nano-TiO2 and polydiallyldimethylammonium chloride, forms a coating layer by using the adsorption of amino group of the silane coupling agent and polydiallyldimethylammonium chloride to the carboxyl group on the surface of the carbon fiber, then adds graphene oxide water dispersion liquid, uses the carboxyl group on the surface of the graphene oxide to load on the surface of the coating layer, and finally heats to carbonize the organic matter in the coating layer to obtain modified carbon fiber. Compared with simply adding carbon fiber or graphene oxide, the modified carbon fiber obtained above can improve the dispersibility of graphene oxide in the castable, more and more uniform SiC whiskers are formed by Si and graphene oxide in the castable at high temperature, the high temperature toughness and corrosion resistance of the castable are improved, the surface hydrophilicity of the carbon fiber is improved, so that the carbon fiber is more uniformly dispersed in the castable, the agglomeration is reduced, and the toughening effect is better. The graphene oxide and nano-TiO2 in the coating layer can also play a role in relieving the high temperature oxidation of the carbon fiber, so that the high temperature toughness and crack resistance of the graphene oxide and the carbon fiber are better, and the TiO2 can improve the corrosion resistance of the castable. At the same time, the carbon coating layer formed by high temperature carbonization on the surface of the carbon fiber can also play a bonding and bridging role, so that the nano-TiO2 and the graphene oxide are more stably combined on the surface of the carbon fiber, and a three-dimensional carbon chain structure is formed, further improving the high temperature toughness and high temperature stability of the castable. Therefore, the blast furnace trough refractory castable has excellent high temperature mechanical properties, thermal shock resistance and corrosion resistance, can effectively prolong the service life of the castable, and improve the cast iron production efficiency. DETAILED DESCRIPTION

[0029] Hereinafter, the technical solutions of the application will be described in detail through specific examples.

[0030] Example 1

[0031] A blast furnace trough refractory castable comprises a main material and an additive;

[0032] The main material comprises the following raw materials in mass percentage: corundum 73.5%, silicon carbide 15%, alpha-Al2O3 micro powder 3%, SiO2 micro powder 4%, calcium aluminate cement 3%, elemental silicon powder 0.7%, and spherical pitch 0.8%;

[0033] The additive comprises modified carbon fiber and sodium tripolyphosphate; wherein the amount of the modified carbon fiber is 0.6% of the mass of the main material, and the amount of the sodium tripolyphosphate is 0.2% of the mass of the main material;

[0034] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, with a mass ratio of 1:0.8:0.8:0.25:0.25;

[0035] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm and silicon carbide fine powder with a particle size less than 0.088 mm, with a mass ratio of 1:1;

[0036] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm;

[0037] The preparation method of the modified carbon fiber is as follows:

[0038] S1, carbon fibers with a length of 5 mm are placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and are heated for oxidation treatment at 80°C for 3 h, and then are washed and dried to obtain oxidized carbon fibers;

[0039] S2, the oxidized carbon fibers are added into a coating modification liquid and stirred for 8 min, and then are centrifuged and washed to obtain coated carbon fibers; wherein the mass ratio of the oxidized carbon fibers to the coating modification liquid is 1:8, and the coating modification liquid comprises the following components with the following mass percentages: 0.6% of silane coupling agent modified nano-TiO2, 0.7% of polydiallyldimethylammonium chloride, and the balance of water;

[0040] The preparation method of the silane coupling agent modified nano-TiO2 is as follows: nano-TiO2 is added into deionized water and uniformly dispersed to obtain a nano-TiO2 water dispersion liquid; an ethanol solution of silane coupling agent KH-550 is added into the nano-TiO2 water dispersion liquid, and is fully stirred for 3 h, and then is centrifuged and dried, to obtain the silane coupling agent modified nano-TiO2, wherein the mass ratio of the silane coupling agent KH-550 to the nano-TiO2 is 1:10;

[0041] S3, the coated carbon fibers are added into a graphene oxide water dispersion liquid with a concentration of 5 mg / mL and stirred for 5 min, and then are centrifuged and washed, and are heated for carbonization at 650°C for 1.5 h under a nitrogen atmosphere, to obtain the modified carbon fibers, wherein the ratio of the coated carbon fibers to the graphene oxide water dispersion liquid is 1 g:15 mL.

[0042] The preparation method of the above-mentioned blast furnace iron notch refractory castable is as follows: the main materials of the castable are uniformly mixed, and then the additive is added and uniformly stirred, to obtain the castable.

[0043] Example 2

[0044] A blast furnace iron notch refractory castable comprises main materials and an additive.

[0045] The main material comprises raw materials in the following mass percentages: corundum 60%, silicon carbide 24.5%, α-Al2O3 micro powder 5%, SiO2 micro powder 4%, calcium aluminate cement 4%, elemental silicon powder 1%, and spherical pitch 1.5%;

[0046] The additive comprises modified carbon fibers and sodium tripolyphosphate; wherein the amount of modified carbon fibers is 0.4% of the mass of the main material, and the amount of sodium tripolyphosphate is 0.1% of the mass of the main material;

[0047] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:0.5:0.5:0.2:0.2;

[0048] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and silicon carbide fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:0.8;

[0049] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm;

[0050] The preparation method of the modified carbon fibers is as follows:

[0051] S1, carbon fibers with a length of 5 mm are placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, heated and oxidized at 75°C for 4 h, then washed and dried to obtain oxidized carbon fibers;

[0052] S2, the oxidized carbon fibers are added to a coating modification liquid and stirred for 5 min, then centrifuged and washed to obtain coated carbon fibers; wherein the mass ratio of oxidized carbon fibers to coating modification liquid is 1:5, and the coating modification liquid comprises the following components in the following mass percentages: silane coupling agent modified nano-TiO2 0.5%, polydiallyldimethylammonium chloride 0.5%, and the balance is water; the preparation method of the silane coupling agent modified nano-TiO2 is the same as that of Example 1;

[0053] S3, the coated carbon fibers are added to an oxidized graphene water dispersion liquid with a concentration of 5 mg / mL and stirred for 5 min, then centrifuged and washed, and heated and carbonized at 500°C for 2 h under a nitrogen atmosphere, to obtain the coated carbon fibers, wherein the ratio of coated carbon fibers to oxidized graphene water dispersion liquid is 1 g:10 mL.

[0054] The preparation method of the above blast furnace iron notch refractory castable is as follows: the main material of the castable is mixed uniformly, then the additive is added and stirred uniformly, to obtain the blast furnace iron notch refractory castable.

[0055] Embodiment 3

[0056] A blast furnace trough refractory castable, comprising a main material and an additive;

[0057] The main material comprises raw materials in the following mass percentages: corundum 75%, silicon carbide 10%, α-Al2O3 micro powder 5.5%, SiO2 micro powder 4.5%, calcium aluminate cement 4%, elemental silicon powder 0.5%, and spherical pitch 0.5%;

[0058] The additive comprises modified carbon fibers and sodium hexametaphosphate; wherein the amount of the modified carbon fibers is 0.8% of the mass of the main material, and the amount of the sodium hexametaphosphate is 0.3% of the mass of the main material;

[0059] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:1:1:0.3:0.3;

[0060] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and silicon carbide fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:1.5;

[0061] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm;

[0062] The preparation method of the modified carbon fibers is as follows:

[0063] S1, carbon fibers with a length of 5 mm are placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, heated and oxidized at 85°C for 2 h, then washed and dried to obtain oxidized carbon fibers;

[0064] S2, the oxidized carbon fibers are added to a coating modification liquid and stirred for 10 min, then centrifuged and washed to obtain coated carbon fibers; wherein the mass ratio of the oxidized carbon fibers to the coating modification liquid is 1:10, and the coating modification liquid comprises the following components in the following mass percentages: silane coupling agent modified nano-TiO2 1%, polydiallyldimethylammonium chloride 0.8%, and the balance being water; the preparation method of the silane coupling agent modified nano-TiO2 is the same as that of Embodiment 1;

[0065] S3, the coated carbon fibers are added to an oxidized graphene aqueous dispersion liquid with a concentration of 10 mg / mL and stirred for 10 min, then centrifuged and washed, and carbonized at 800°C for 1 h under a nitrogen atmosphere, to obtain the modified carbon fibers, wherein the ratio of the coated carbon fibers to the oxidized graphene aqueous dispersion liquid is 1 g:20 mL.

[0066] The preparation method of the blast furnace trough refractory castable is as follows: the main material of the castable is mixed uniformly, then the additive is added, and stirred uniformly to obtain the blast furnace trough refractory castable.

[0067] Comparative Example 1

[0068] A blast furnace trough refractory castable comprises a main material and an additive.

[0069] The main material comprises raw materials in the following mass percentages: corundum 73.5%, silicon carbide 15%, α-Al2O3 micro powder 3%, SiO2 micro powder 4%, calcium aluminate cement 3%, elemental silicon powder 0.7%, and spherical pitch 0.8%.

[0070] The additive comprises modified carbon fiber and sodium tripolyphosphate; wherein the amount of the modified carbon fiber is 0.6% of the mass of the main material, and the amount of the sodium tripolyphosphate is 0.2% of the mass of the main material.

[0071] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:0.8:0.8:0.25:0.25.

[0072] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and silicon carbide fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:1.

[0073] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm.

[0074] The preparation method of the modified carbon fiber is as follows:

[0075] The carbon fiber with a length of 5 mm is placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and is subjected to oxidation treatment at 80°C for 3 h, and then is washed and dried to obtain the modified carbon fiber.

[0076] The preparation method of the blast furnace trough refractory castable is as follows: the main material of the castable is mixed uniformly, then the additive is added, and stirred uniformly to obtain the blast furnace trough refractory castable.

[0077] Comparative Example 2

[0078] A blast furnace trough refractory castable comprises a main material and an additive.

[0079] The main material comprises raw materials in the following mass percentages: corundum 73.5%, silicon carbide 15%, α-Al2O3 micro powder 3%, SiO2 micro powder 4%, calcium aluminate cement 3%, elemental silicon powder 0.7%, and spherical pitch 0.8%;

[0080] The additive comprises modified carbon fibers and sodium tripolyphosphate; wherein the amount of the modified carbon fibers is 0.6% of the mass of the main material, and the amount of the sodium tripolyphosphate is 0.2% of the mass of the main material;

[0081] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:0.8:0.8:0.25:0.25;

[0082] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm and silicon carbide fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:1;

[0083] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm;

[0084] The preparation method of the modified carbon fibers is as follows:

[0085] S1, carbon fibers with a length of 5 mm are placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, heated and oxidized at 80℃ for 3 h, then washed and dried to obtain oxidized carbon fibers;

[0086] S2, the oxidized carbon fibers are added to a coating modification liquid and stirred for 8 min, then centrifuged and washed to obtain coated carbon fibers; wherein the mass ratio of the oxidized carbon fibers to the coating modification liquid is 1:8, and the coating modification liquid comprises the following components in the following mass percentages: silane coupling agent modified nano-TiO2 0.6%, and the balance is water; the preparation method of the silane coupling agent modified nano-TiO2 is the same as that of Example 1;

[0087] S3, the coated carbon fibers are added to a graphene oxide aqueous dispersion liquid with a concentration of 5 mg / mL and stirred for 5 min, then centrifuged and washed, and heated and carbonized at 650℃ for 1.5 h under a nitrogen atmosphere, to obtain the product, wherein the ratio of the coated carbon fibers to the graphene oxide aqueous dispersion liquid is 1 g:15 mL.

[0088] The preparation method of the above blast furnace trough refractory castable is as follows: the main material of the castable is mixed uniformly, then the additive is added and stirred uniformly, to obtain the product.

[0089] Comparative Example 3

[0090] A blast furnace trough refractory castable, comprising a main material and an additive;

[0091] The main material comprises raw materials in the following mass percentages: corundum 73.5%, silicon carbide 15%, α-Al2O3 micro powder 3%, SiO2 micro powder 4%, calcium aluminate cement 3%, elemental silicon powder 0.7%, and spherical pitch 0.8%;

[0092] The additive comprises modified carbon fibers and sodium tripolyphosphate; wherein the amount of the modified carbon fibers is 0.6% of the mass of the main material, and the amount of the sodium tripolyphosphate is 0.2% of the mass of the main material;

[0093] The corundum is composed of corundum particles with a particle size less than 8 mm and greater than or equal to 5 mm, corundum particles with a particle size less than 5 mm and greater than or equal to 3 mm, corundum particles with a particle size less than 3 mm and greater than or equal to 1 mm, corundum particles with a particle size less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:0.8:0.8:0.25:0.25;

[0094] The silicon carbide is composed of silicon carbide particles with a particle size less than 1 mm and greater than or equal to 0.088 mm and silicon carbide fine powder with a particle size less than 0.088 mm, in a mass ratio of 1:1;

[0095] The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm;

[0096] The preparation method of the modified carbon fibers is as follows:

[0097] S1, carbon fibers with a length of 5 mm are placed in a mixed acid solution composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, heated and oxidized at 80°C for 3 h, then washed and dried to obtain oxidized carbon fibers;

[0098] S2, the oxidized carbon fibers are added to a coating modification liquid and stirred for 8 min, then centrifuged and washed to obtain coated carbon fibers; wherein the mass ratio of the oxidized carbon fibers to the coating modification liquid is 1:8, and the coating modification liquid comprises the following components in the following mass percentages: polydiallyldimethylammonium chloride 0.7%, and the balance being water;

[0099] S3, the coated carbon fibers are added to an oxidized graphene aqueous dispersion liquid with a concentration of 5 mg / mL and stirred for 5 min, then centrifuged and washed, and carbonized at 650°C for 1.5 h under a nitrogen atmosphere, to obtain the modified carbon fibers, wherein the ratio of the coated carbon fibers to the oxidized graphene aqueous dispersion liquid is 1 g:15 mL.

[0100] The preparation method of the blast furnace trough refractory castable is as follows: uniformly mixing the main materials of the castable, then adding the additive and uniformly stirring to obtain the castable.

[0101] Test example

[0102] The castable of each of Examples 1 and Comparative Examples 1-3 is mixed with 5% water by weight of the castable, uniformly mixed, vibration formed, demolded after curing at room temperature for 24 hours, then heat treated at 110°C for 24 hours and at 1500°C for 3 hours, and the high temperature strength of the test piece is tested according to GB / T 3002-2017 and the linear change rate of the test piece is tested according to GB / T 5988-2007, and the test results are shown in Table 1:

[0103] Table 1

[0104]

[0105] Therefore, the castable has excellent normal temperature and high temperature bending strength and stability, which is beneficial to improve the thermal shock resistance and service life.

[0106] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A refractory castable for blast furnace tapping troughs, characterized in that, Includes main ingredients and additives; The main material comprises the following raw materials in the following mass percentages: corundum 60%-75%, silicon carbide 10%-30%, α-Al2O3 micro powder 2%-6%, SiO2 micro powder 1%-5%, calcium aluminate cement 1%-4%, elemental silica powder 0.5%-1%, and spherical asphalt 0.5%-1.5%, the sum of the above raw material mass percentages being 100%. The additives include modified carbon fiber and a water-reducing agent; wherein the amount of modified carbon fiber is 0.4-0.8% of the mass of the main material, and the amount of water-reducing agent is 0.1-0.3% of the mass of the main material; The method for preparing the modified carbon fiber includes: S1. Place the carbon fiber in a mixed acid solution and heat it for oxidation treatment to obtain oxidized carbon fiber; S2. The oxidized carbon fiber is added to the coating modification solution and stirred thoroughly, then centrifuged and washed to obtain coated carbon fiber; the coating modification solution comprises the following components by mass percentage: 0.5-1% silane coupling agent modified nano-TiO2, 0.5-0.8% polydiallyldimethylammonium chloride, and the balance being water; the silane coupling agent modified nano-TiO2 is obtained by surface modification of nano-TiO2 with a silane coupling agent, and the silane coupling agent is silane coupling agent KH-540, KH-550 or a combination thereof; S3. Add the coated carbon fiber to a graphene oxide aqueous dispersion with a concentration of 5-10 mg / mL and stir thoroughly. Then centrifuge, wash, and heat and carbonize at 500-800℃ for 1-2 hours under an inert atmosphere to obtain the product. The ratio of the coated carbon fiber to the graphene oxide aqueous dispersion is 1 g: (10-20) mL.

2. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, In S1, the mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1; In S1, the temperature for heating oxidation treatment is 75-85℃, and the time is 2-4h.

3. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, In S2, the mass ratio of the oxidized carbon fiber to the coating modification liquid is 1:(5-10). In S2, the stirring time is 5-10 minutes.

4. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, In S3, the stirring time is 5-10 minutes.

5. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, The length of the carbon fiber is 1-10 mm.

6. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, The corundum is composed of corundum particles with a diameter of less than 8 mm and greater than or equal to 5 mm, corundum particles with a diameter of less than 5 mm and greater than or equal to 3 mm, corundum particles with a diameter of less than 3 mm and greater than or equal to 1 mm, corundum particles with a diameter of less than 1 mm and greater than or equal to 0.088 mm, and corundum fine powder with a diameter of less than 0.088 mm in a mass ratio of 1:(0.5-1):(0.5-1):(0.2-0.3):(0.2-0.3).

7. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, The silicon carbide is composed of silicon carbide particles with a particle size of less than 1 mm and greater than or equal to 0.088 mm and silicon carbide fine powder with a particle size of less than 0.088 mm in a mass ratio of 1:(0.8-1.5).

8. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, The particle size of the α-Al2O3 micro powder is 1-3 μm, and the particle size of the SiO2 micro powder is 1-3 μm.

9. The refractory castable for blast furnace tapping troughs according to claim 1, characterized in that, The water-reducing agent is sodium tripolyphosphate, sodium hexametaphosphate, or a combination thereof.

10. A method for preparing a refractory castable for a blast furnace tapping trough as described in any one of claims 1-9, characterized in that, Mix the main components of the castable material evenly, then add the additives and stir evenly to obtain the final product.

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