Blast furnace tapping channel spray coating and spray repairing method thereof

Abstract

The invention provides a blast furnace tapping channel spray coating which comprises the following raw material components in percentage by mass: 40-50 parts of brown aluminum oxide, 10-20 parts of silicon carbide, 10-15 parts of nano aluminum oxide micro powder, 5-10 parts of nano sol, 3-5 parts of an antioxidant, 2-3 parts of an anti-explosion agent, 1-2 parts of an accelerator and the balance of a binder and other auxiliary materials. Comprising the following steps: cleaning the surface of the eroded part of the blast-furnace tapping channel, uniformly mixing and spraying a blast-furnace tapping channel spray coating on the working surface of the eroded part; the thickness of each layer is smaller than or equal to 50 mm, and layer-by-layer spraying is carried out; after the spraying is finished, directly putting into use; or the spraying area is baked, so that the spraying material is put into use after being rapidly cured; by optimizing the material composition and the spraying process, the corrosion resistance and thermal shock resistance of the spraying material are remarkably improved, the damage frequency of the coating is effectively reduced, the service life of the blast furnace tapping channel is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, in particular to a blast furnace tapping ditch spray material and a spray repair method thereof. Background Art

[0002] The blast furnace's taphole is a critical component in the ironmaking process, guiding the flow of high-temperature molten iron. Its operating environment is extremely harsh, requiring it to withstand multiple complex conditions, including high temperatures, thermal shock, mechanical erosion, and chemical attack. In actual production, the refractory material of the taphole is gradually damaged by the long-term erosion and erosion of high-temperature molten iron, leading to problems such as narrowing of the trough and molten iron leakage, seriously affecting the normal operation and production efficiency of the blast furnace. Traditional repair methods mainly use castables for repair, but this method has shortcomings such as long construction time, low coating strength, and poor thermal shock resistance, making it difficult to meet the requirements of modern blast furnace production for rapid repair and efficient operation. Summary of the Invention

[0003] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a blast furnace iron ditch spray coating material and a spray repair method thereof, which is used to solve the problem that the traditional repair method mainly uses castables for repair, but this method has the disadvantages of long construction time, low coating strength, poor thermal shock resistance, etc., which is difficult to meet the requirements of modern blast furnace production for rapid repair and efficient operation.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a blast furnace tapping ditch spray material, which comprises the following raw material components in percentage by mass:

[0005] Brown corundum 40-50 parts, silicon carbide 10-20 parts, nano alumina powder 10-15 parts, nano sol 5-10 parts, antioxidant 3-5 parts, explosion-proof agent 2-3 parts, accelerator 1-2 parts, the rest are binders and other auxiliary materials.

[0006] The present invention also provides a method for spraying and repairing the blast furnace tapping channel spray coating material as described above, comprising the following steps:

[0007] S1. Clean the eroded surface of the blast furnace tapping channel;

[0008] S2. Mix the blast furnace tapping ditch spray material evenly and spray it on the eroded working surface;

[0009] S3. Spray in layers according to the depth of the erosion area, with each layer thickness ≤ 50mm, spray layer by layer;

[0010] S4. After spraying is completed, it can be put into use directly; or, the sprayed area can be baked to allow the sprayed material to cure quickly before being put into use.

[0011] As described above, the blast furnace tapping ditch spray coating material and the spray repair method thereof of the present invention have the following beneficial effects:

[0012] The present invention significantly enhances the strength and density of the coating by adding high-performance materials such as brown corundum, silicon carbide, and nano-alumina powder to the spray coating, and fills the tiny gaps between the materials through the three-dimensional network structure formed by the nanosol, effectively reducing shrinkage and cracking at high temperatures. The composite binder can quickly form stable chemical bonds at room temperature, improving the initial adhesion of the spray coating, and further enhancing the overall strength of the material at high temperatures, ensuring that the coating is firmly attached to the work surface. Furthermore, the synergistic effect of the nanosol, nano-zirconia powder, and graphene nanosheets forms an efficient heat conduction network, accelerating heat transfer and reducing thermal stress concentration, thereby significantly improving the thermal shock resistance of the coating and extending its service life. Furthermore, the present invention effectively prevents the spray coating from bursting during the hot pouring process by adding a composite explosion-proof agent and a nitrogen-atomized spherical aluminum powder antioxidant to the spray coating, while preventing the oxidation of silicon carbide powder and carbon, thereby improving the safety and reliability of the coating.

[0013] The spray repair method of the present invention adopts a segmented baking technology to flexibly adjust the baking time according to the spray thickness, thereby ensuring rapid solidification of the spray material, reducing thermal stress concentration, and further improving the thermal shock resistance and bonding strength of the coating; further, by adopting multi-layer staggered spraying and progressive spraying technology, the coating structure is optimized, ensuring coating uniformity, reducing coating defects, and at the same time enhancing overall strength and corrosion resistance.

[0014] The present invention significantly improves the corrosion resistance and thermal shock resistance of the spray coating by optimizing the material composition and spraying process, effectively reduces the damage frequency of the coating, extends the service life of the blast furnace iron ditch, and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a process flow chart of the spray repair method of the present invention.

[0016] Figure 2 Schematic diagram of multi-layer staggered spraying. DETAILED DESCRIPTION

[0017] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all subranges between a minimum of 1 and a maximum of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, and the like.

[0019] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; and, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of implementation of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0020] A first aspect of the present invention provides a blast furnace tapping ditch spray material comprising the following raw material components, calculated by mass percentage:

[0021] Brown corundum 40-50 parts, 40-42 parts, 42-44 parts, 44-46 parts, 46-48 parts or 48-50 parts, silicon carbide 10-20 parts, 10-12 parts, 12-14 parts, 14-16 parts, 16-18 parts or 18-20 parts, nano alumina powder 10-15 parts, 10-12 parts, 12-14 parts or 14-15 parts, nano sol 5-10 parts, 5-7 parts, 7-9 parts or 9-10 parts, antioxidant 3-5 parts, 3-4 parts or 4-5 parts, explosion-proof agent 2-3 parts, 2-2.5 parts or 2.5-3 parts, quick-setting agent 1-2 parts, 1-1.5 parts or 1.5-2 parts, and the rest are binders and other auxiliary materials.

[0022] In the present invention, the brown corundum is continuously graded, and the particle size specifications include 1mm-0mm and 3mm-1mm, the Al2O3 content is ≥94.5wt%, and the interval screening content is ≥90wt%.

[0023] In the present invention, the silicon carbide is continuously graded, with particle size specifications including 1mm-0mm and 3mm-1mm, SiC content ≥97wt%, and interval screening content ≥90wt%.

[0024] In the present invention, the nano sol is nano silica sol. The present invention uses nano sol to replace traditional water casting to improve the bonding strength and thermal shock resistance of the material.

[0025] In the present invention, the nanosol has a particle size of 5 to 20 nm, for example, 5 to 10 nm, 10 to 15 nm, or 15 to 20 nm. The nanosol is evenly dispersed in the spray coating, forming a three-dimensional network structure that effectively fills tiny gaps between materials, enhances the density of the spray coating, and reduces shrinkage and cracking of the spray coating at high temperatures.

[0026] In the present invention, the antioxidant is nitrogen-atomized spherical aluminum powder with an Al content of ≥99 wt% and a particle size of 1 to 1.5 μm, such as 1 to 1.2 μm, 1.2 to 1.4 μm, or 1.4 to 1.5 μm. The antioxidant is used to prevent oxidation of the silicon carbide powder and carbon, thereby extending the life of the coating.

[0027] In the present invention, the explosion-proof agent is a composite explosion-proof agent composed of nitrogen-atomized spherical aluminum powder and explosion-proof fibers in a mass ratio of 1:1-1.5, 1:1-1.1, 1:1.1-1.2, 1:1.2-1.3, 1:1.3-1.4, or 1:1.4-1.5. The explosion-proof agent can rapidly release gas at high temperatures, preventing the spray coating from bursting during hot casting. By adding the composite explosion-proof agent and nitrogen-atomized spherical aluminum powder antioxidant to the spray coating, the present invention can effectively prevent the spray coating from bursting during hot casting, while also preventing oxidation of silicon carbide powder and carbon, thereby improving the safety and reliability of the coating.

[0028] In the present invention, the quick-setting agent is liquid water glass, preferably having a modulus of 3.0. The quick-setting agent can cause the material to flocculate within 10 seconds after spraying, preventing it from flowing.

[0029] In the present invention, the binder is a composite binder composed of polyphosphate and nano-silica sol in a mass ratio of 1:1-2, 1:1-1.2, 1:1.2-1.4, 1:1.4-1.6, 1:1.6-1.8, or 1:1.8-2. The composite binder of polyphosphate and nano-silica sol can quickly form stable chemical bonds at room temperature, improving initial adhesion, and further enhance the overall strength and thermal shock resistance of the material at high temperatures, ensuring that the coating is firmly adhered to the work surface.

[0030] In the present invention, the other auxiliary materials include 0.1-0.5 parts, 0.1-0.2 parts, 0.2-0.4 parts or 0.4-0.5 parts of nano zirconium oxide powder.

[0031] In a preferred embodiment of the present invention, the nano-zirconia powder has a particle size of 20 to 50 nm, for example, 20 to 30 nm, 30 to 40 nm, or 40 to 50 nm. The nano-zirconia powder can form a stable zirconia ceramic phase at high temperatures, further enhancing the thermal shock resistance and erosion resistance of the spray coating.

[0032] In the present invention, the other auxiliary materials further include 0.2-0.8 parts, 0.2-0.4 parts, 0.4-0.6 parts or 0.6-0.8 parts of graphene nanosheets.

[0033] In a preferred embodiment of the present invention, the graphene nanoplatelets have a purity greater than 99.5%, a thickness of 4-20 nm, 4-7 nm, 7-10 nm, 10-12 nm, 12-14 nm, 14-16 nm, 16-18 nm, or 18-20 nm, and a platelet diameter (D50) less than 10 μm. The graphene nanoplatelets can be evenly dispersed in the spray coating, forming a thermally conductive network that significantly improves the thermal conductivity of the spray coating, thereby accelerating heat transfer and distribution, reducing thermal stress concentration in the spray coating at high temperatures, and further enhancing the thermal shock resistance and service life of the spray coating.

[0034] The second aspect of the present invention provides a method for spraying and repairing the blast furnace tapping channel spray coating material as described above, such as Figure 1 As shown, the following steps are included:

[0035] S1. Clean the eroded area of ​​the blast furnace tapping channel;

[0036] S2. Mix the blast furnace tapping ditch spray material evenly and spray it on the eroded working surface;

[0037] S3. Spray in layers according to the depth of the erosion area, with each layer thickness ≤ 50mm, spray layer by layer;

[0038] S4. After spraying is completed, it can be put into use directly; or, the sprayed area can be baked to allow the sprayed material to cure quickly before being put into use.

[0039] In the present invention, the eroded area in step S1 can be cleaned by using an excavator to remove the slag blocks on the working surface of the eroded area of ​​the blast furnace iron ditch, and using an air duct to blow away the broken slag on the working surface of the eroded area.

[0040] In the present invention, the spraying in step S2 is performed using a spraying device. The nanosol is fed through the spray gun of the sprayer and mixed with other spray material components. The accelerator is atomized at the spray gun and sprayed out of the mixture. The distance between the spray gun discharge port and the eroded working surface is maintained between 600 mm and 900 mm, and the nozzle is perpendicular to the eroded working surface.

[0041] In the present invention, the layered spraying in step S3 adopts a multi-layer staggered spraying technology, and the thickness of each layer is 20-30 mm, 20-22 mm, 22-24 mm, 24-26 mm, 26-28 mm or 28-30 mm, and the adjacent layers form a staggered angle of 45°-60°, 45°-50°, 50°-55° or 55°-60°, such as Figure 2 This staggered spraying method can significantly improve the adhesion and uniformity of the sprayed coating, reduce coating defects caused by a single spraying direction, and enhance the overall strength and erosion resistance of the coating.

[0042] Furthermore, the layered spraying described in step S3 adopts a multi-layer progressive spraying technology, increasing the content of the nanosol in the spray coating layer by layer from the bottom layer to the surface layer, and increasing each layer by 1 to 2 parts, 1 to 1.2 parts, 1.2 to 1.4 parts, 1.4 to 1.6 parts, 1.6 to 1.8 parts or 1.8 to 2 parts. The progressive spraying method enables the bottom layer spray coating to quickly solidify and form a supporting structure, and the surface spray coating further enhances the density and thermal shock resistance by increasing the nanosol content, significantly improving the overall performance and service life of the coating. The present invention optimizes the coating structure, ensures the uniformity of the coating, reduces coating defects, and enhances the overall strength and erosion resistance by adopting multi-layer staggered spraying and multi-layer progressive spraying technology. The inner layer is sprayed with the base spray coating, and the outer layer is sprayed with the enhanced coating to achieve simultaneous construction, greatly reducing the construction time and improving the repair efficiency.

[0043] In the present invention, when the total thickness of the spraying in step S3 is less than 50 mm, the baking step of step S4 is not required; or, when the total thickness of the spraying in step S3 is 50-100 mm, the baking time of step S4 is 30-50 min, 30-35 min, 35-40 min, 40-45 min or 45-50 min; or, when the total thickness of the spraying in step S3 is greater than 100 mm, the baking time of step S4 is 50-60 min, 50-55 min or 55-60 min.

[0044] In the present invention, in step S4, the baking adopts a segmented baking technology: first baking at a temperature of 200-300°C, 200-250°C, or 250-300°C for 5-10 minutes, then baking at a temperature of 500-600°C, 500-550°C, or 550-600°C for 10-20 minutes, 10-15 minutes, or 15-20 minutes, and finally baking at a temperature of 700-800°C, 700-750°C, or 750-800°C for 15-30 minutes, 15-20 minutes, 20-25 minutes, or 25-30 minutes. The segmented baking method can effectively reduce the thermal stress concentration of the spray coating at high temperatures and improve the thermal shock resistance and bonding strength of the coating.

[0045] In the present invention, in step S4, the baking is performed using a gas burner to bake the sprayed area for a baking time of 30 to 60 minutes, 30 to 35 minutes, 35 to 40 minutes, 40 to 45 minutes, 45 to 50 minutes, 50 to 55 minutes, or 55 to 60 minutes to ensure rapid curing of the sprayed material. During the baking process, a spot check is performed every 25 to 35 minutes, 25 to 30 minutes, or 30 to 35 minutes to prevent the gas fire from being extinguished or gas leaking.

[0046] The blast furnace tapping channel spray coating material and the spray repair method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] Blast furnace tapping hook spray coating:

[0049] In terms of mass percentage, it includes the following raw material components

[0050] 45 parts of brown corundum, 18 parts of silicon carbide, 12 parts of nano-alumina powder, 6 parts of nano-silica sol, 4 parts of antioxidant (nitrogen atomized spherical aluminum powder), 2.5 parts of explosion-proof agent (nitrogen atomized spherical aluminum powder: explosion-proof fiber = 1:1.3), 1.5 parts of accelerating agent (liquid water glass, modulus 3.0), 10 parts of composite binder (polyphosphate: nano-silica sol = 1:1.5), 0.3 parts of nano-zirconia powder, and 0.5 parts of graphene nanosheets.

[0051] Spray repair method:

[0052] S1. Surface cleaning: Use an excavator to clean the eroded slag, and use an air duct to blow away the debris to ensure that the working surface is flat;

[0053] S2. Spraying operation: The nanosol is fed into the spray gun of the spray machine and mixed with other spray material components. The accelerator is atomized at the spray gun and sprayed out. The distance between the spray gun outlet and the working surface is kept at 750mm. Spray vertically. The thickness of each layer is 25mm. The staggered angle of adjacent layers is 55 degrees. Spray layer by layer.

[0054] S3. Baking and curing: The total thickness of the spray coating is 80mm, and the baking is carried out in stages: 250℃ for 8 minutes; 550℃ for 15 minutes; 800℃ for 20 minutes. During the baking process, the coating is inspected every 30 minutes.

[0055] S4. Inspection and commissioning: Check that the coating is free of defects before commissioning.

[0056] Example 2

[0057] Blast furnace tapping hook spray coating:

[0058] In terms of mass percentage, it includes the following raw material components

[0059] 45 parts of brown corundum, 18 parts of silicon carbide, 12 parts of nano-alumina powder, 8 parts of nano-silica sol, 4 parts of antioxidant (nitrogen atomized spherical aluminum powder), 2.5 parts of explosion-proof agent (nitrogen atomized spherical aluminum powder: explosion-proof fiber = 1:1.3), 1.5 parts of accelerating agent (liquid water glass, modulus 3.0), 10 parts of composite binder (polyphosphate: silica sol = 1:1.5), 0.3 parts of nano-zirconia powder, and 0.5 parts of graphene nanosheets.

[0060] Spray repair method:

[0061] Step S1 is the same as in Example 1;

[0062] S2. Spraying operation: The nanosol is fed into the spray gun of the spray machine and mixed with other spray material components. The accelerator is atomized at the spray gun and sprayed out. The distance between the spray gun outlet and the working surface is kept at 750mm. Spray vertically. The thickness of each layer is 25mm. The staggered angle of adjacent layers is 55 degrees. Spray layer by layer.

[0063] S3. Baking and curing: The total thickness of the spray coating is 100mm, and the baking is carried out in stages: 200℃ baking for 10 minutes; 500℃ baking for 15 minutes; 800℃ baking for 20 minutes. During the baking process, the coating is inspected every 30 minutes.

[0064] Step S4 is the same as in Example 1.

[0065] Example 3

[0066] Blast furnace tapping hook spray coating:

[0067] In terms of mass percentage, it includes the following raw material components

[0068] 45 parts of brown corundum, 18 parts of silicon carbide, 12 parts of nano-alumina powder, 8 parts of nano-silica sol, 4 parts of antioxidant (nitrogen atomized spherical aluminum powder), 2.5 parts of explosion-proof agent (nitrogen atomized spherical aluminum powder: explosion-proof fiber = 1:1.3), 1.5 parts of accelerating agent (liquid water glass, modulus 3.0), 10 parts of composite binder (polyphosphate: silica sol = 1:1.5), 0.3 parts of nano-zirconia powder, and 0.5 parts of graphene nanosheets.

[0069] Spray repair method:

[0070] Step S1 is the same as in Example 1;

[0071] S2. Spraying operation: The nanosol is fed into the spray gun of the spray machine and mixed with other spray material components. The accelerator is atomized at the spray gun and sprayed out. The distance between the spray gun outlet and the working surface is maintained at 750mm. The spraying is carried out vertically. The thickness of each layer is 25mm. The progressive spraying technology is used. The content of nanosol in the bottom layer is 5 parts, and it increases by 1 part layer by layer, with a maximum of 8 parts.

[0072] S3. Baking and curing: If the total spray thickness is less than 50mm, it can be put into use directly without baking; if the thickness is ≥50mm, adopt segmented baking, baking at 200℃ for 5 minutes, 600℃ for 10 minutes, and 800℃ for 15 minutes. During the baking process, check every 25 minutes.

[0073] S4. Inspection and commissioning: Check that the coating is free of defects before commissioning.

[0074] Example 4

[0075] Blast furnace iron removal hook spray coating:

[0076] In terms of mass percentage, it includes the following raw material components

[0077] 45 parts of brown corundum, 18 parts of silicon carbide, 12 parts of nano-alumina powder, 10 parts of nano-silica sol, 4 parts of antioxidant (nitrogen atomized spherical aluminum powder), 2.5 parts of explosion-proof agent (nitrogen atomized spherical aluminum powder: explosion-proof fiber = 1:1.3), 1.5 parts of accelerating agent (liquid water glass, modulus 3.0), 10 parts of composite binder (polyphosphate: silica sol = 1:1.5), 0.3 parts of nano-zirconia powder, and 0.5 parts of graphene nanosheets.

[0078] Spray repair method:

[0079] Step S1 is the same as in Example 1;

[0080] S2. Spraying operation: The nanosol is fed into the spray gun of the spray machine and mixed with other spray material components. The accelerator is atomized at the spray gun and sprayed out. The distance between the spray gun outlet and the working surface is kept at 750mm. Spray vertically. The thickness of each layer is 25mm. The staggered angle of adjacent layers is 55 degrees. Spray layer by layer.

[0081] S3. Baking and curing: If the total spraying thickness is less than 50mm, it can be put into use directly without baking; if the thickness is ≥50mm, adopt segmented baking: baking at 200℃ for 10 minutes; baking at 600℃ for 10 minutes; baking at 800℃ for 20 minutes. During the baking process, check every 30 minutes.

[0082] Step S4 is the same as in Example 1.

[0083] Example 5

[0084] Blast furnace deironing hook spray coating: same as Example 3.

[0085] Spray repair method: multi-layer staggered spraying combined with multi-layer progressive spraying technology, each layer spraying thickness is 25mm, the adjacent layer staggered angle is 55°, the bottom layer nanosol content is 5 parts, increasing by 1 part layer by layer, the maximum amount is 8 parts, and the remaining steps are the same as Example 3.

[0086] Comparative Example 1

[0087] A cement-bonded spray coating (our company's blast furnace tapping ditch spray coating BC-60G) was used, the spray coating was mixed with water at the spray gun tip, and spray repair was performed using a multi-layer staggered spraying technique. The specific steps were the same as in Example 2.

[0088] Performance testing:

[0089] The blast furnace tapholes repaired by spraying in the above examples and comparative examples were tested for compressive strength according to GB / T 5072-2008 and flexural strength according to GB / T 3001-2017. The results are shown in Table 1.

[0090] Table 1

[0091]

[0092]

[0093] It can be seen from the data in Table 1 that in Example 1, when the content of the nanosol is 6 parts, the multi-layer staggered spraying technology is adopted, and the compressive strength at 1450°C is ≥35MPa, and the flexural strength at 1450°C is ≥7MPa. In Example 2, when the content of the nanosol is 8 parts, the multi-layer staggered spraying technology is adopted, and the compressive strength at 1450°C is ≥80MPa, and the flexural strength at 1450°C is ≥12MPa. It can be seen that when the content of the nanosol is increased from 6 parts to 8 parts, the spraying performance of the spray coating is improved.

[0094] Comparison between Example 2 and Example 3: In Example 2, when the content of nanosol is 8 parts and the multi-layer staggered spraying technology is adopted, the compressive strength at 1450°C is ≥80MPa, and the flexural strength at 1450°C is ≥12MPa. In Example 3, when the content of nanosol is 8 parts and the multi-layer progressive spraying is adopted, the compressive strength at 1450°C is ≥90MPa, and the flexural strength at 1450°C is ≥14MPa. It can be seen that the multi-layer progressive spraying technology is beneficial to improving the spraying performance.

[0095] Embodiment 1, embodiment 2 and embodiment 4 compare: among the embodiment 1, when the content of nanosol is 6 parts, when adopting the multi-layer staggered spraying technology, 1450 ℃ of compressive strength ≥35MPa, 1450 ℃ of flexural strength ≥7MPa, among the embodiment 2, when the content of nanosol is 8 parts, when adopting the multi-layer staggered spraying technology, 1450 ℃ of compressive strength ≥80MPa, 1450 ℃ of flexural strength ≥12MPa, among the embodiment 4, when the content of nanosol is 10 parts, when adopting the multi-layer staggered spraying technology, 1450 ℃ of compressive strength ≥50MPa, 1450 ℃ of flexural strength ≥10MPa, it can be seen from this, when the content of nanosol is 8 parts, the spraying performance of spray coating is best, and when the content of nanosol is greater than or less than 8 parts, the spraying performance of spray coating decreases.

[0096] Example 5 combines multi-layer staggered spraying with multi-layer progressive spraying technology, with a compressive strength of ≥105MPa at 1450°C and a flexural strength of ≥14Mpa at 1450°C, and a service life extended to 18 days. It can be seen that the technology of combining multi-layer staggered spraying with multi-layer progressive spraying can further improve the spraying performance of the spray material.

[0097] After the spray coating prepared in the embodiment of the present invention repairs the lining of the blast furnace main groove, its service life can reach more than 10 days, while the spray coating currently used in comparative example 1 can generally only be used for 3 to 5 days after repair, and the iron passing capacity is 10,000 to 20,000 tons; after using the spray coating of the present invention, at least 40,000 to 60,000 tons of iron can be passed, which significantly improves the service life and production efficiency of the blast furnace iron groove.

[0098] Gunning repair of the blast furnace tapping channel is generally performed after the iron is tapped, and any slag and iron residue on the lining must be removed. Gunning repair can be performed within the following temperature range: Gunning repair can begin when the temperature drops to 400°C to 800°C; gunning repair can also be performed at room temperature. The overall thickness of the gunning repair layer should be controlled between 50 and 150 mm to ensure uniformity and adhesion of the coating.

[0099] As can be seen from Examples 1 to 5, Example 2 is suitable for conventional repair needs, with balanced performance and a simple construction process. Example 3 significantly improves the thermal shock resistance of the coating by increasing the nanosol content and adopting a multi-layer progressive spraying method, making it suitable for high thermal shock and high corrosion environments. By comparing the above four examples, the most appropriate spray coating formulation and spraying process can be selected according to the specific working conditions and repair requirements of the blast furnace iron trough.

[0100] Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0101] 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 skilled in 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 one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A blast furnace tapping ditch spray material, characterized in that: In parts by weight, it includes the following raw material components: Brown corundum 40-50 parts, silicon carbide 10-20 parts, nano alumina powder 10-15 parts, nano sol 5-10 parts, antioxidant 3-5 parts, explosion-proof agent 2-3 parts, accelerator 1-2 parts, the rest are binders and other auxiliary materials.

2. The blast furnace tapping ditch spray material according to claim 1, characterized in that: The brown corundum is continuously graded, with particle size specifications including 1mm-0mm and 3mm-1mm, Al2O3 content ≥94.5wt%, and interval screening content ≥90wt%; And / or, the silicon carbide is continuously graded, with particle size specifications including 1mm-0mm and 3mm-1mm, SiC content ≥97wt%, and interval screening content ≥90wt%; And / or, the nanosol is nanosilica sol; and / or, the particle size of the nanosol is 5 to 20 nm; And / or, the antioxidant is nitrogen atomized spherical aluminum powder, with an Al content of ≥99wt% and a particle size of 1 to 1.5um; And / or, the explosion-proof agent is a composite explosion-proof agent composed of nitrogen atomized spherical aluminum powder and explosion-proof fiber in a mass ratio of 1:1 to 1.5; And / or, the quick-setting agent is liquid water glass; And / or, the binder is a composite binder composed of polyphosphate and nano-silica sol in a mass ratio of 1:1-2.

3. The blast furnace tapping ditch spray material according to claim 1, characterized in that: The other auxiliary materials include 0.1-0.5 parts of nano zirconium oxide powder.

4. The blast furnace tapping ditch spray material according to claim 3, characterized in that: The particle size of the nano zirconium oxide powder is 20 to 50 nm.

5. The blast furnace tapping ditch spray material according to claim 1, characterized in that: The other auxiliary materials also include 0.2-0.8 parts of graphene nanosheets based on the total mass of the spray coating.

6. The blast furnace tapping ditch spray material according to claim 5, characterized in that: The graphene nanosheets have a purity greater than 99.5%, a thickness of 4 to 20 nm, and a sheet diameter D50 less than 10 μm.

7. A method for spraying and repairing a blast furnace tapping channel spray coating material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Clean the eroded surface of the blast furnace tapping channel; S2. Mix the blast furnace tapping ditch spray material evenly and spray it on the eroded working surface; S3. Spray in layers according to the depth of the erosion area, with each layer thickness ≤ 50mm, spray layer by layer; S4. After spraying is completed, it can be put into use directly; or, the sprayed area can be baked to allow the sprayed material to cure quickly before being put into use.

8. The spray repair method according to claim 7, characterized in that: The layered spraying in step S3 adopts a multi-layer staggered spraying technology, with each layer having a thickness of 20 to 30 mm and adjacent layers forming a staggered angle of 45° to 60°.

9. The spray repair method according to claim 7, characterized in that: The layered spraying in step S3 adopts a multi-layer progressive spraying technology. When the thickness of each spray layer is 20 to 30 mm, the content of the nanosol in the spray material is increased layer by layer from the bottom layer to the surface layer, and each layer is increased by 1 to 2 parts.

10. The spray repair method according to claim 7, characterized in that: When the total thickness of the spray coating in step S3 is less than 50 mm, the baking step in step S4 is not required; or, when the total thickness of the spray coating in step S3 is 50 to 100 mm, the baking time in step S4 is 30 to 50 minutes; or, when the total thickness of the spray coating in step S3 is greater than 100 mm, the baking time in step S4 is 50 to 60 minutes; And / or, in step S4, the baking adopts a segmented baking technology: first baking at a temperature of 200-300°C for 5-10 minutes, then baking at a temperature of 500-600°C for 10-20 minutes, and finally baking at a temperature of 700-800°C for 15-30 minutes; and / or, in step S4, the baking adopts a gas burner to bake the sprayed area, and the baking time is 30-60 minutes.

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