Blast furnace tapping channel iron falling point castable and preparation method thereof

Abstract

The invention relates to the technical field of blast furnace tapping channel castable, in particular to a blast furnace tapping channel iron falling point castable and a preparation method thereof. The castable is prepared from the following raw materials: recycled aluminum oxide ceramic, special-grade high-aluminum clinker, corundum, ceramic waste, a carbon material, silicon carbide, a binding agent and an additive, the preparation method comprises the following steps: S1, mixing the recycled aluminum oxide ceramic, the special-grade high-aluminum clinker, the corundum, the ceramic waste, the carbon material, the silicon carbide, the binding agent and the additive to obtain a mixture; s2, performing dry mixing and stirring on the mixture obtained in the step S1, and adding water for mixing to obtain slurry; s3, the slurry obtained in the step S2 is poured into a mold, pouring vibration molding, demolding, drying, heat preservation and cooling are conducted, and the composite material is obtained. The prepared castable is high in high-temperature strength, compact in volume density, high in molten iron seepage resistance, high in scouring resistance, not prone to being bonded with a metal solution and high in thermal shock resistance, oxidation resistance and metal solution corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace tapping channel castables, in particular to a blast furnace tapping channel iron drop point castable and a preparation method thereof. Background Art

[0002] The blast furnace taphole is the channel through which high-temperature molten iron and slag flow. As blast furnaces develop towards larger sizes, the amount of iron flowing through increases, the time of iron flowing through lengthens, and the interval between tappings shortens, which places more stringent requirements on the materials used in the blast furnace taphole.

[0003] At present, most of the large and medium-sized blast furnace iron-making plants in my country use Al2O3-SiC-C iron ditch castables, whose main raw materials are brown corundum and silicon carbide, which are relatively expensive. As the steel industry enters a recession, refractory materials have become an important part of its cost reduction and efficiency improvement. At the same time, under the current market economy conditions, competition is increasingly fierce, and the overall contracting price of refractory materials in iron-making plants is constantly lowering. Under the premise of ensuring the safe, efficient and long-life operation of the iron ditch, it is urgent to reduce the raw material cost of the iron ditch castable. At the same time, with the continuous improvement of smelting technology, the iron-passing time is extended and the iron-making interval is short, which increases the degree of erosion and damage of the refractory materials of the iron ditch.

[0004] Chinese patent CN116639963A discloses a refractory castable for the iron ditch of the blast furnace iron-making yard and a preparation method thereof, comprising the following components: 45-55 parts of fused brown corundum; 15-25 parts of silicon carbide; 10-15 parts of composite micropowder; 2-5 parts of Secar71 high-alumina cement; 2-4 parts of metallic silicon powder; among which the silicon carbide component accounts for a large proportion, which leads to an increase in material cost.

[0005] Chinese patent CN112408957B discloses an iron ditch castable and a preparation method thereof; the castable comprises, by weight: 33-36 parts of homogenized alumina, 22-24 parts of brown corundum, 24-27 parts of silicon carbide, 2.35-2.60 parts of carbon material, 2.30-2.60 parts of binder, 8.0-8.8 parts of ultrafine powder, 0.05-0.08 parts of explosion-proof agent, 3.24-3.58 parts of antioxidant and 0.18-0.23 parts of water reducer. The castable prepared by the formula has a low density, and the particle gaps between the materials cannot be effectively filled, which leads to a low resistance to molten iron permeability.

[0006] Therefore, there is an urgent need to provide a refractory castable for a blast furnace tapping channel with a long life, low production cost and high performance. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a blast furnace tapping channel iron point castable and a preparation method thereof, so as to solve the problems of low production cost and poor performance of the castable in the prior art.

[0008] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0009] The first aspect of the present invention is to provide a castable for the iron-falling point of a blast furnace tapping ditch, wherein the castable comprises the following raw materials in parts by weight: 13 to 25 parts of recycled alumina ceramics, 15 to 21 parts of special high-aluminum clinker, 22 to 24 parts of corundum, 24 to 27 parts of ceramic waste, 2.35 to 2.60 parts of carbon material, 10 to 11 parts of silicon carbide, 2.30 to 2.60 parts of a binder, and 8 to 13 parts of an additive.

[0010] The second aspect of the present invention is to provide a method for preparing a blast furnace tapping channel iron point castable, comprising the following steps:

[0011] S1. Mixing recycled alumina ceramics, special high-aluminum clinker, corundum, ceramic waste, carbon material, silicon carbide, a binder, and an additive to obtain a mixture;

[0012] S2, dry-mixing the mixture obtained in step S1, adding water and mixing to obtain a slurry;

[0013] S3, pouring the slurry obtained in step S2 into a mold, casting and vibrating to form, demoulding, drying, heat preservation, and cooling. As described above, a blast furnace tapping ditch iron point castable and a preparation method thereof of the present invention have the following beneficial effects:

[0014] (1) The blast furnace tapping ditch iron point castable of the present invention is achieved by multi-level matching of corundum particles and micropowder materials, and at the same time, silicon carbide is added, thereby improving the slag resistance and erosion resistance of the blast furnace tapping ditch iron point castable. By replacing part of the silicon carbide in the refractory material with ceramic waste, the amount of silicon carbide used is greatly reduced, which is beneficial to environmental protection and cost reduction. The castable has high high-temperature strength, dense bulk density, strong resistance to molten iron penetration, strong erosion resistance, is not easy to bond with metal solution, and has strong thermal shock resistance, oxidation resistance, and metal solution corrosion resistance.

[0015] (2) The blast furnace tapping ditch iron drop point castable of the present invention introduces an admixture, which includes nano alumina powder, a composite explosion-proof agent, an antioxidant, and a composite water reducing agent. The components cooperate with each other and react with other raw materials of the castable to improve the performance of the castable. DETAILED DESCRIPTION

[0016] In order to make the purpose of the invention, technical solutions and beneficial technical effects of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0017] The first aspect of the present invention is to provide a castable for the iron-falling point of a blast furnace tapping ditch, wherein the castable comprises the following raw materials in parts by weight: 13 to 25 parts of recycled alumina ceramics, 15 to 21 parts of special high-aluminum clinker, 22 to 24 parts of corundum, 24 to 27 parts of ceramic waste, 2.35 to 2.60 parts of carbon material, 10 to 11 parts of silicon carbide, 2.30 to 2.60 parts of a binder, and 8 to 13 parts of an additive.

[0018] In some embodiments of the present invention, the castable includes the following raw materials in parts by weight: 13 to 25 parts of recycled alumina ceramics, 15 to 21 parts of special high-alumina clinker, 22 to 24 parts of corundum, 24 to 27 parts of ceramic waste, 2.35 to 2.60 parts of carbon material, 10 to 11 parts of silicon carbide, 2.30 to 2.60 parts of binder, and 8 to 13 parts of admixture.

[0019] In some specific embodiments of the present invention, the castable includes the following raw materials in parts by weight: 13 to 20 parts of recycled alumina ceramics, 15 to 18 parts of special grade high aluminum clinker, 22 to 23 parts of corundum, 24 to 25 parts of ceramic waste, 2.35 to 2.40 parts of carbon material, 10 to 10.5 parts of silicon carbide, 2.30 to 2.40 parts of binder, and 8 to 11.47 parts of admixture.

[0020] In some specific embodiments of the present invention, the castable includes the following raw materials in parts by weight: 20-25 parts of recycled alumina ceramics, 18-21 parts of special grade high aluminum clinker, 23-24 parts of corundum, 25-27 parts of ceramic waste, 2.40-2.60 parts of carbon material, 10.5-11 parts of silicon carbide, 2.40-2.60 parts of binder, and 11.47-13 parts of admixture.

[0021] In some specific embodiments of the present invention, the castable includes the following raw materials in parts by weight: 13 parts of recycled alumina ceramics, 15 parts of special high-alumina clinker, 22 parts of corundum, 24 parts of ceramic waste, 2.35 parts of carbon material, 10 parts of silicon carbide, 2.30 parts of binder, and 11.47 parts of admixture.

[0022] In some specific embodiments of the present invention, the castable includes the following raw materials in parts by weight: 18 parts of recycled alumina ceramics, 19 parts of special high-alumina clinker, 23 parts of corundum, 25 parts of ceramic waste, 2.50 parts of carbon material, 10.5 parts of silicon carbide, 2.45 parts of binder, and 8.56 parts of admixture.

[0023] In some specific embodiments of the present invention, the castable includes the following raw materials in parts by weight: 25 parts of recycled alumina ceramics, 21 parts of special high-alumina clinker, 24 parts of corundum, 27 parts of ceramic waste, 2.60 parts of carbon material, 11 parts of silicon carbide, 2.60 parts of binder, and 12.69 parts of admixture.

[0024] In some embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8.0 to 8.8 portions of nano alumina powder, 0.05 to 0.08 portions of composite explosion-proof agent, 3.24 to 3.58 portions of antioxidant, and 0.18 to 0.23 portions of composite water reducing agent.

[0025] In some specific embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8.0 to 8.5 parts of nano alumina powder, 0.05 to 0.06 parts of composite explosion-proof agent, 3.24 to 3.42 parts of antioxidant, and 0.18 to 0.21 parts of composite water reducing agent.

[0026] In some specific embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8.5 to 8.8 portions of nano alumina powder, 0.06 to 0.08 portions of composite explosion-proof agent, 3.42 to 3.58 portions of antioxidant, and 0.21 to 0.23 portions of composite water reducing agent.

[0027] In some specific embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8 parts of nano alumina powder, 0.05 parts of composite explosion-proof agent, 3.24 parts of antioxidant, and 0.18 parts of composite water reducing agent.

[0028] In some specific embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8.5 parts of nano alumina powder, 0.06 parts of composite explosion-proof agent, 3.42 parts of antioxidant, and 0.21 parts of composite water reducing agent.

[0029] In some specific embodiments of the present invention, each portion of the admixture comprises the following raw materials in parts by weight: 8.8 parts of nano alumina powder, 0.08 parts of composite explosion-proof agent, 3.58 parts of antioxidant, and 0.23 parts of composite water reducing agent.

[0030] In some embodiments of the present invention, the particle size of the nano-alumina is 50-60 nm, the Al2O3 content is greater than 99%, and K2O+Na2O≤0.1%.

[0031] The blast furnace tapping channel iron drop point castable of the present invention ensures that the material has good slag resistance and anti-scouring performance through multi-level matching of corundum particles and micro powder materials and the addition of silicon carbide. In addition, by adding nano alumina powder with a particle size of 50 to 80 nm, the nano alumina powder has a small particle size and a large specific surface area. On the one hand, it can effectively fill the particle gap, promote sintering, reduce the amount of water added to the castable, improve the density and strength, and greatly improve the operating performance and use performance of the castable; in addition, under high temperature conditions, the nano alumina powder can react with silicon to form a slag-resistant castable. SiO2 generated after oxidation of micropowder or SiC reacts to form mullite, which improves the thermal shock resistance and erosion resistance of the castable. By adding a small amount of nano alumina powder, the castable performance can be greatly improved. By replacing part of the silicon carbide in the refractory material with ceramic waste, the amount of silicon carbide used is greatly reduced, which is beneficial to environmental protection and cost reduction. The castable has high high-temperature strength, dense bulk density, strong resistance to molten iron penetration, strong erosion resistance, is not easy to bond with metal solution, and has strong thermal shock resistance, oxidation resistance, and metal solution corrosion resistance.

[0032] In some embodiments of the present invention, the composite explosion-proof agent is selected from at least two of aluminum powder, aluminum lactate, and explosion-proof fiber; preferably, the composite explosion-proof agent is composed of aluminum powder, aluminum lactate, and explosion-proof fiber in a mass ratio of (2-3): 1: 1. The particle size of the aluminum powder is 325 mesh; the explosion-proof fiber is polypropylene fiber, and the diameter of the explosion-proof fiber is 4 mm.

[0033] In some embodiments of the present invention, the composite water reducer is selected from at least two of sodium tripolyphosphate, naphthalenesulfonate water reducer, and polycarboxylic acid high-efficiency water reducer; preferably, the composite water reducer is composed of sodium tripolyphosphate, naphthalenesulfonate water reducer, and polycarboxylic acid high-efficiency water reducer in a mass ratio of (1-2): 1: 1. The present invention has no special limitation on the source of the naphthalenesulfonate water reducer, and a commercial product of a naphthalenesulfonate water reducer well known to those skilled in the art can be used; the present invention has no special limitation on the source of the polycarboxylic acid high-efficiency water reducer, and a commercial product of a polycarboxylic acid high-efficiency water reducer well known to those skilled in the art can be used.

[0034] In some embodiments of the present invention, the antioxidant is selected from silicon powder and aluminum powder, and the antioxidant is composed of silicon powder and aluminum powder in a mass ratio of (2-3):1. Preferably, the antioxidant is composed of silicon powder and aluminum powder in a mass ratio of 2:1; the silicon powder is composed of an average particle size of 45.22 μm and an average particle size of 2.82 μm in a mass ratio of (1-2): (1-2). The antioxidant is composed of an average particle size of 45.22 μm, an average particle size of 2.82 μm, and aluminum powder in a mass ratio of 1:1:1. The present invention has no special limitation on the source of silicon powder, and commercially available silicon powder products well known to those skilled in the art can be used; the present invention has no special limitation on the source of aluminum powder, and commercially available aluminum powder products well known to those skilled in the art can be used.

[0035] In some embodiments of the present invention, the corundum is selected from one or more of white corundum, brown corundum, and compact corundum; preferably, the corundum is composed of white corundum, brown corundum, and compact corundum in a mass ratio of (2-3): (4-5): (1-2); the Al2O3 content in the corundum is ≥95%; the volume density is ≥3.5g / cm 3 ; The particle size of the corundum is selected from at least one of 1-3 mm, 0.15-1 mm, and 325 mesh; further preferably, the corundum is composed of particles with a particle size of 1-3 mm, a particle size of 0.15-1 mm, and a particle size of 325 mesh in a mass ratio of (2-3): (1-2): (1-2); the screening content of the 1-3 mm and 0.15-1 mm intervals is ≥90wt%, and the content under the 325 mesh sieve is ≥90wt%. The present invention has no special limitation on the source of the corundum, and a commercially available product of corundum well known to those skilled in the art can be used.

[0036] In some embodiments of the present invention, the particle size of the special high-aluminum clinker is selected from at least one of 5-8mm, 3-5mm and 1-3mm; the Al2O3 content of the special high-aluminum clinker is ≥88wt%, and the Fe2O3 content is ≤1.5wt%; preferably, the special high-aluminum clinker is composed of particles with a particle size of 5-8mm, a particle size of 3-5mm, and a particle size of 1-3mm in a mass ratio of (2-4): (1-2): (1-2); the interval screening content is ≥90wt%. The present invention has no special limitation on the source of the special high-aluminum clinker, and commercial products of special high-aluminum clinker well known to those skilled in the art can be used.

[0037] In some embodiments of the present invention, the present invention has no particular limitation on the source of the carbon material, and commercially available carbon materials well known to those skilled in the art may be used.

[0038] In some embodiments of the present invention, the SiC content in the silicon carbide is ≥97wt%; the particle size of the silicon carbide is selected from at least one of 0.088-1mm and 325 mesh; further preferably, the silicon carbide is composed of particles with a particle size of 0.088-1mm and a particle size of 325 mesh in a mass ratio of (1-2): (4-6); the screening content in the range of 0.088-1mm is ≥90wt%, and the content under the 325 mesh is ≥90wt%. The present invention has no special limitation on the source of silicon carbide, and commercially available products of silicon carbide well known to those skilled in the art can be used.

[0039] In some embodiments of the present invention, the ceramic waste is silicon carbide ceramics; that is, silicon carbide ceramics for filtering aluminum metal liquid. After long-term use, some aluminum and other impurities will adhere to its surface. Preferably, the chemical composition of the ceramic waste is SiC90%~95%, Al5%~8%, and other 0~3%; the other part is a small amount of iron oxide and calcium oxide; the particle size of the ceramic waste is selected from at least one of 0.088~1mm and 0~0.075mm; the particle size of the ceramic waste is composed of 0.088~1mm and 0~0.075mm in a mass ratio of 1:(1.4~1.6).

[0040] In some embodiments of the present invention, the binder is pure calcium aluminate cement, and the Al2O3 content of the pure calcium aluminate cement is greater than 78%. The present invention has no special limitation on the source of the pure calcium aluminate cement, and commercially available products of pure calcium aluminate cement well known to those skilled in the art can be used.

[0041] In some embodiments of the present invention, the Al2O3 content of the recycled alumina ceramic is ≥ 95%, and its volume density is ≥ 3.10 g / cm 3 .

[0042] The second aspect of the present invention is to provide a method for preparing a blast furnace tapping channel iron point castable, comprising the following steps:

[0043] S1. Mixing recycled alumina ceramics, special high-aluminum clinker, corundum, ceramic waste, carbon material, silicon carbide, a binder, and an additive to obtain a mixture;

[0044] S2, dry-mixing the mixture obtained in step S1, adding water and mixing to obtain a slurry;

[0045] S3, pouring the slurry obtained in step S2 into a mold, casting and vibrating to form, demoulding, drying, heat preservation, and cooling to obtain.

[0046] In some embodiments of the present invention, the mass ratio of the mixture to water in step S2 is 100:4.2-4.5. Specifically, the mass ratio of the mixture to water can be 100:4.2-4.3, 100:4.3-4.5; typically but not limiting, for example, it can be 100:4.2, 100:4.3, 100:4.5.

[0047] In some embodiments of the present invention, the dry mixing time in step S2 is 1 to 2 minutes; the mixing time in step S2 is 3 to 5 minutes.

[0048] In some embodiments of the present invention, the drying temperature in step S3 is 105-115° C., and the drying time is 20-24 hours.

[0049] In some embodiments of the present invention, the insulation temperature in step S3 is 1440-1460° C., and the insulation time is 3-5 hours.

[0050] The present invention is further described below by way of examples, but the scope of the present invention is not limited thereto.

[0051] When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. If specific conditions are not specified in the embodiment, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for all reagents or instruments, they are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any method, equipment, and material of the prior art similar or equivalent to the method, equipment, and material in the embodiments of the present invention can also be used to realize the present invention.

[0052] Table 1 Raw material composition ratio of additives for blast furnace tapping ditch iron point castables in Examples 1-3 and Comparative Examples 1-2

[0053]

[0054] Preparation example of admixture

[0055] Preparation Example 1

[0056] The composition ratio of the additive raw material of this preparation example is shown in Table 1. The particle size of nano alumina is 50-60nm, the Al2O3 content is greater than 99%, and K2O+Na2O≤0.1%. The composite explosion-proof agent is composed of aluminum powder, aluminum lactate, and explosion-proof fiber in a mass ratio of 2:1:1. The particle size of the aluminum powder is 325 mesh; the explosion-proof fiber is polypropylene fiber, and the diameter of the explosion-proof fiber is 1.56dtex and the length is 4mm. The composite water reducer is composed of sodium tripolyphosphate, naphthalenesulfonate water reducer, and polycarboxylic acid high-efficiency water reducer in a mass ratio of 1.5:1:1. The manufacturer of the naphthalenesulfonate water reducer in this preparation example is BASF; the manufacturer of the polycarboxylic acid high-efficiency water reducer in this preparation example is Henan Mingzhixin Chemical Products Co., Ltd.; the antioxidant in this preparation example is composed of an average particle size of 45.22μm, an average particle size of 2.82μm, and aluminum powder in a mass ratio of 1:1:1.

[0057] Preparation Example 2

[0058] The composition ratio of the raw materials of the additives in this preparation example is shown in Table 1. The difference from Preparation Example 1 is that the composition ratio of the raw materials is different.

[0059] Preparation Example 3

[0060] The composition ratio of the raw materials of the additives in this preparation example is shown in Table 1. The difference from Preparation Example 1 is that the composition ratio of the raw materials is different.

[0061] Preparation Example 4

[0062] The composition ratio of the additive raw materials in this preparation example is shown in Table 1. The difference from Preparation Example 3 is that conventional high-purity α-Al2O3 micropowder is used instead of nano alumina powder. The high-purity α-Al2O3 micropowder has a particle size of 1.2μm-2μm, an Al2O3 content of >99wt%, and Fe and Si contents of ≤0.05wt%.

[0063] Table 2 Ratio of raw material components for castables at the blast furnace tapping point of Example 1-3 and Comparative Example 1-2

[0064]

[0065] Table 3 Preparation examples of additives used for casting materials at the iron point of the blast furnace iron ditch in Examples 1-3 and Comparative Examples 1-2

[0066]

[0067] Example

[0068] Example 1

[0069] The present embodiment is a blast furnace tapping channel iron point castable, the raw material composition ratio is shown in Table 2. Among them, the admixture is prepared in Preparation Example 1; the Al2O3 content in the corundum is ≥95%; the volume density is ≥3.5g / cm 3 ; The corundum is composed of white corundum, brown corundum and dense corundum in a mass ratio of 2:5:1; the corundum is composed of particles with a diameter of 1 to 3 mm, a diameter of 0.15 to 1 mm and a diameter of 325 mesh in a mass ratio of 2:1:1; the screening content of 1 to 3 mm and 0.15 to 1 mm intervals is ≥90wt%, and ≥90wt% under 325 mesh sieve; the special high-aluminum clinker is composed of particles with a diameter of 5 to 8 mm, a diameter of 3 to 5 mm and a diameter of 1 to 3 mm in a mass ratio of 2:1:1; the screening content of the interval is ≥90wt%; the manufacturer of the special high-aluminum clinker is Qixian Haoxin Refractory Co., Ltd.; the SiC content in silicon carbide is ≥97wt%; the silicon carbide is composed of particles with a diameter of 0.088 to 1 mm and a diameter of The ceramic waste is composed of 325 meshes at a mass ratio of 1:4; the screening content in the range of 0.088-1mm is ≥90wt%, and the content under the 325 mesh is ≥90wt%; the ceramic waste is silicon carbide ceramics; the chemical composition of the ceramic waste is SiC90%-95%, Al5%-8%, and the others are 0-3%; the particle size of the ceramic waste is composed of 0.088-1mm and 0-0.075mm at a mass ratio of 1:1.5; the manufacturer of the ceramic waste is Gongyi Hongfeng Refractory Materials Co., Ltd.; the binder is pure calcium aluminate cement, and the Al2O3 content of the pure calcium aluminate cement is greater than 78%; the Al2O3 content in the recycled alumina ceramic is ≥95%, and its volume density is ≥3.10g / cm 3 ; The manufacturer of recycled alumina ceramics is Gongyi Hongfeng Refractory Materials Co., Ltd.; the manufacturer of carbon materials is Tianjin Huaya Weiye Chemical Technology Co., Ltd.

[0070] This embodiment provides a method for preparing a castable material for a blast furnace tapping channel, comprising the following steps:

[0071] S1. Mixing recycled alumina ceramics, special high-aluminum clinker, corundum, ceramic waste, carbon material, silicon carbide, a binder, and an additive to obtain a mixture;

[0072] S2, dry-mixing the mixture obtained in step S1 for 2 minutes, adding water and mixing for 4 minutes to obtain a slurry; wherein the mass ratio of the mixture to water is 100:4.4;

[0073] S3, pouring the slurry obtained in step S2 into a mold, casting and vibrating, demoulding, drying, heat preservation, and cooling to obtain. The drying temperature is 110°C, the drying time is 23h, the heat preservation temperature is 1450°C, and the heat preservation time is 4h.

[0074] Example 2

[0075] The castable material for the blast furnace tapping channel iron point of this embodiment has a raw material composition ratio as shown in Table 2. The difference from Example 1 is that the raw material composition ratio is different, and the admixture is prepared in Preparation Example 2.

[0076] Example 3

[0077] The castable for the blast furnace tapping channel iron point of this embodiment has a raw material composition ratio as shown in Table 2. The difference from Example 1 is that the raw material composition ratio is different, and the admixture is prepared in Preparation Example 3.

[0078] Comparative Example

[0079] Comparative Example 1

[0080] The comparative example is a blast furnace tapping channel iron point castable, the raw material composition ratio is shown in Table 2, and the admixture is shown in Table 3 and Table 1. The difference from Example 3 is that silicon carbide is used to replace ceramic waste, and the silicon carbide SiC content is ≥97wt%; it is divided into two gradations according to the particle size: 0.088mm<particle size≤1mm and particle size 325 mesh, and the admixture is obtained in Preparation Example 3.

[0081] Comparative Example 2

[0082] The comparative example is a blast furnace tapping channel iron point castable, the raw material composition ratio is shown in Table 2, and the admixture is shown in Table 3 and Table 1. The difference from Example 3 is that the admixture is shown in Table 3, and the admixture is obtained in Preparation Example 4.

[0083] Performance Testing

[0084] Bulk density test: Take a blast furnace tapping ditch iron point castable of Example 1-3 and Comparative Example 1-2, and test the bulk density of the castable according to the test method in GB / T2997-2015 "Test method for bulk density, apparent porosity and true porosity of dense shaped refractory products". The test results are shown in Table 4.

[0085] Room temperature flexural strength test: Take a blast furnace tapping ditch iron drop point castable of Example 1-3 and Comparative Example 1-2, and test the flexural strength of the castable according to the test method in GB / T3001-2017 "Test method for flexural strength of refractory materials at room temperature". The test results are shown in Table 4.

[0086] High temperature flexural strength test: Take a blast furnace tapping ditch iron point castable of Example 1-3 and Comparative Example 1-2, and test the flexural strength of the castable according to the test method in GB / T 3002-2004 "Test method for high temperature flexural strength of refractory materials". The test results are shown in Table 4.

[0087] Compressive strength test: Take a blast furnace tapping ditch iron point castable of Example 1-3 and Comparative Example 1-2, and test the compressive strength of the castable according to the test method in GB / T5072-2008 "Test method for compressive strength of refractory materials at room temperature". The test results are shown in Table 4.

[0088] Linear change rate detection: Take a blast furnace tapping ditch iron drop point castable of Example 1-3 and Comparative Example 1-2, and detect the linear change rate of the castable according to the detection method in GB / T5988-2007 "Test method for permanent linear change of refractory materials heated". The test results are shown in Table 4.

[0089] Oxidation resistance test of decarburized layer thickness: Take a blast furnace tapping ditch iron drop point castable of Example 1-3 and Comparative Example 1-2, and test the decarburized layer thickness of the castable according to the test method in GB / T13244-1991 "Test method for oxidation resistance of carbon-containing refractory materials". The test results are shown in Table 4.

[0090] Average erosion depth of slag erosion resistance: Take a blast furnace tapping ditch iron drop point castable of Example 1-3 and Comparative Example 1-2, and test the average erosion depth of the castable according to the test method in GB / T13244-1991 "Test method for oxidation resistance of carbon-containing refractory materials". The test results are shown in Table 4.

[0091] Table 4 Performance test results of castables at the blast furnace tapping channel of Examples 1-3 and Comparative Examples 1-2

[0092]

[0093] Combining Examples 1-3 and the data in Table 4, it can be seen that the castables prepared in Examples 1-3 have excellent properties, and the bulk density after drying at 110°C*24h is greater than 3g / cm 3 , the flexural strength after drying at 110℃*24h is greater than 5.9MPa, the compressive strength after drying at 110℃*24h is greater than 40Mpa, the flexural strength after sintering at 1450℃*3h is greater than 11Mpa, the compressive strength is greater than 90Mpa, the linear change rate is small, the high temperature flexural strength test after sintering at 1450℃*0.5h is greater than 2.9Mpa, the thickness of the decarburized layer after sintering at 1400℃*2h is less than 1.8mm, and at 1500℃*3h, the average erosion depth is less than 1.5mm. Under the above-mentioned detection conditions, the performance of the blast furnace iron outlet main groove castable obtained in Example 3 is the best overall.

[0094] In combination with Example 3 and Comparative Example 1, and in combination with the data in Table 4, it can be seen that the flexural strength, compressive strength and high-temperature flexural strength of the castable prepared in Example 3 are greater than the flexural strength, compressive strength and high-temperature flexural strength of the castable prepared in Comparative Example 1, and the linear change rate, decarburization layer thickness and average erosion depth of the castable prepared in Example 3 are less than the linear change rate, decarburization layer thickness and average erosion depth of the castable prepared in Comparative Example 1. The difference between Example 3 and Comparative Example 1 is that Example 3 uses ceramic waste to replace part of the silicon carbide, and the castable thus prepared has better comprehensive performance. Using ceramic waste to replace part of the silicon carbide reduces the cost on the one hand, and on the other hand, the ceramic waste cooperates with other components in the raw materials such as admixtures, binders, carbon materials, corundum, etc., which is convenient for improving the flexural strength and compressive strength of the castable prepared, and the castable has better oxidation resistance and slag erosion resistance.

[0095] Combining Example 3 and Comparative Example 2, and combining the data in Table 4, it can be seen that the flexural strength, compressive strength, linear change rate, oxidation resistance, and slag erosion resistance of the castable prepared in Example 3 are all better. The difference between Example 3 and Comparative Example 4 is that Example 3 uses the admixture prepared in Preparation Example 3, to which nano alumina powder is added, while Comparative Example 4 uses the admixture prepared in Preparation Example 4, and conventional high-purity α-Al2O3 micropowder is used in the admixture to replace the nano alumina powder. Since the admixtures used in Example 3 and Comparative Example 4 are different, the coordination effects between the admixture and other components are different. The nano alumina powder in the admixture in Example 3 has a small particle size, can fill the gap between particles, promote sintering, and improve density. Under high temperature conditions, the nano alumina powder reacts with silicon dioxide generated after oxidation of silicon carbide to generate mullite, thereby improving the flexural strength, compressive strength and slag erosion resistance of the castable.

[0096] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A blast furnace tapping channel iron point castable, characterized in that: The castable includes the following raw materials in parts by weight: 13-25 parts of recycled alumina ceramics, 15-21 parts of special high-aluminum clinker, 22-24 parts of corundum, 24-27 parts of ceramic waste, 2.35-2.60 parts of carbon materials, 10-11 parts of silicon carbide, 2.30-2.60 parts of binders, and 8-13 parts of additives.

2. A blast furnace tapping channel iron point castable according to claim 1, characterized in that: Each portion of the admixture comprises the following raw materials in parts by weight: 8.0 to 8.8 parts of nano alumina powder, 0.05 to 0.08 parts of composite explosion-proof agent, 3.24 to 3.58 parts of antioxidant, and 0.18 to 0.23 parts of composite water reducing agent.

3. A blast furnace tapping channel iron point castable according to claim 2, characterized in that: Also includes one or more of the following characteristics: A1) the particle size of the nano-alumina is 50-60 nm, the Al2O3 content is greater than 99%, and K2O+Na2O≤0.1%; A2) the composite explosion-proof agent is selected from at least two of aluminum powder, aluminum lactate, and explosion-proof fiber; preferably, the composite explosion-proof agent is composed of aluminum powder, aluminum lactate, and explosion-proof fiber in a mass ratio of 2 to 3:1:1; further preferably, the explosion-proof fiber is polypropylene fiber, and the length of the polypropylene fiber is 4 to 6 mm; A3) the composite water reducer is selected from at least two of sodium tripolyphosphate, naphthalenesulfonate water reducer and polycarboxylic acid high efficiency water reducer; A4) The antioxidant is selected from silicon powder and aluminum powder; preferably, the antioxidant is composed of silicon powder and aluminum powder in a mass ratio of (2-3):

1.

4. A blast furnace tapping channel iron point castable according to claim 3, characterized in that: The silicon powder is composed of silicon powder with an average particle size of 45.22 μm and silicon powder with an average particle size of 2.82 μm in a mass ratio of 1-2:1-2.

5. The blast furnace tapping channel iron point castable according to claim 1, characterized in that: Also includes one or more of the following characteristics: (1) The corundum is selected from one or more of white corundum, brown corundum, and compact corundum; preferably, the corundum is composed of white corundum, brown corundum, and compact corundum in a mass ratio of 2-3:4-5:1-2; (2) The particle size of the special grade high aluminum clinker is selected from at least one of 5 to 8 mm, 3 to 5 mm and 1 to 3 mm; (3) The Al2O3 content of the special high-aluminum clinker is ≥88wt% and the Fe2O3 content is ≤1.5wt%; (4) The SiC content in the silicon carbide is ≥ 97wt%; (5) The particle size of the silicon carbide is selected from at least one of 0.088-1 mm and 325 mesh; (6) The ceramic waste is silicon carbide ceramics; preferably, the chemical composition of the ceramic waste is SiC 90% to 95%, Al 5% to 8%, and other 0% to 3%; (7) The particle size of the ceramic waste is selected from at least one of 0.088-1 mm and 0-0.075 mm; (8) The binder is pure calcium aluminate cement, and the Al2O3 content of the pure calcium aluminate cement is greater than 78%; (9) The Al2O3 content of the recycled alumina ceramic is ≥ 95%, and its volume density is ≥ 3.10 g / cm 3 .

6. A blast furnace tapping channel iron point castable according to claim 5, characterized in that: Also includes one or more of the following characteristics: (11) The Al2O3 content of the corundum is ≥ 95%; the bulk density is ≥ 3.5 g / cm 3 ; (12) The particle size of the corundum is selected from at least one of 1-3 mm, 0.15-1 mm, and 325 mesh; preferably, the corundum is composed of particles with a particle size of 1-3 mm, 0.15-1 mm, and 325 mesh in a mass ratio of 2-3:1-2:1-2; the screening content of the 1-3 mm and 0.15-1 mm intervals is ≥90wt%, and the content under the 325 mesh sieve is ≥90wt%; (21) The special grade high aluminum clinker is composed of particles with a diameter of 5 to 8 mm, particles with a diameter of 3 to 5 mm, and particles with a diameter of 1 to 3 mm in a mass ratio of 2-4: 1-2: 1-2; the interval screening content is ≥ 90wt%; (51) The silicon carbide is composed of particles with a diameter of 0.088 to 1 mm and particles with a diameter of 325 mesh in a mass ratio of 1-2:4-6; the screening content in the range of 0.088 to 1 mm is ≥90wt%, and the content under the 325 mesh is ≥90wt%.

7. A method for preparing a blast furnace tapping channel iron point castable as claimed in any one of claims 1 to 6, characterized in that: The steps include: S1. Mixing recycled alumina ceramics, special high-aluminum clinker, corundum, ceramic waste, carbon material, silicon carbide, a binder, and an additive to obtain a mixture; S2, dry-mixing the mixture obtained in step S1, adding water and mixing to obtain a slurry; S3, pouring the slurry obtained in step S2 into a mold, casting and vibrating to form, demoulding, drying, heat preservation, and cooling to obtain.

8. A blast furnace tapping channel iron point castable according to claim 7, characterized in that: The mass ratio of the mixture to water in step S2 is 100:4.2-4.

5.

9. The method for preparing a blast furnace tapping channel iron point castable according to claim 7, characterized in that: Also includes one or more of the following characteristics: S21) The dry mixing time in step S2 is 1 to 2 minutes; S22) The mixing time in step S2 is 3 to 5 minutes.

10. The method for preparing a blast furnace tapping channel iron point castable according to claim 7, characterized in that: Also includes one or more of the following characteristics: S31) The drying temperature in step S3 is 105-115°C and the drying time is 24h; S32) The insulation temperature in step S3 is 1440-1460°C, and the insulation time is 5 hours.

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