Blast furnace slag runner castable and preparation method thereof

Abstract

The invention discloses a blast furnace slag runner castable and a preparation method thereof, and relates to the technical field of refractory materials, and the blast furnace slag runner castable comprises the following raw material components in percentage by mass: 6-9% of 15-8mm brown aluminum oxide, 14-16% of 8-5mm brown aluminum oxide, 17-19% of 5-3mm brown aluminum oxide, 13-15% of 3-1mm brown aluminum oxide, 8-11% of 1-0mm compact corundum, 6-8% of 1-0mm silicon carbide, 3-8% of 1-0mm silicon carbide, and the balance of water. The invention relates to a high-strength wear-resistant ceramic material, which is prepared from the following raw materials in percentage by weight: 8 to 12 percent of 200-mesh silicon carbide, 3 to 5 percent of zirconite-silicon carbide composite powder, 6 to 8 percent of aluminum oxide micro powder, 2 to 3 percent of silicon micro powder, 2 to 2.5 percent of cement, 1 to 3 percent of ball pitch, 0.5 to 2 percent of carbon black, 0.2 to 0.5 percent of boron carbide, 1 to 1.5 percent of metal silicon powder, 0.3 to 0.6 percent of zirconium boride, 0.03 to 0.05 percent of metal aluminum powder, 0.05 to 0.08 percent of organic fiber and 0.1 to 0.2 percent of water reducing agent. The oxidation resistance, slag corrosion resistance and scouring resistance of the blast furnace slag runner castable are improved, the cost is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, and specifically relates to a blast furnace slag trench castable and its preparation method. Background Technology

[0002] Blast furnace slag is a silicate melting byproduct generated during pig iron smelting in the ironmaking process. Its formation originates from the complex physicochemical reactions at high temperatures involving gangue (such as silica and alumina) in iron ore, ash from coke combustion, and added flux (mainly limestone). During smelting, coke acts as fuel and a reducing agent, reducing iron oxides to liquid metallic iron. Meanwhile, calcium oxide (CaO) produced from limestone decomposition combines with acidic oxides (such as SiO2 and Al2O3) in the gangue to form a low-melting-point silicate melt (such as CaSiO3). This melt is produced through density differences (slag density 2.2-3.0 g / cm³). 3 The molten iron content is approximately 7.0 g / cm³. 3 It naturally separates into layers, floats on the surface of the molten iron, and is then discharged through the slag outlet.

[0003] The slag trough is typically located below the blast furnace taphole and connects to the main trough, branch troughs, and slag pots. A well-designed slope and flow channel structure guide the flow of molten slag, ensuring efficient slag-iron separation. The refractory lining of the blast furnace slag trough is generally cast using an Al2O3-SiO2-C system. During blast furnace ironmaking, the molten slag severely damages the slag trough. The molten slag temperature is typically as high as 1400-1500℃, and its alkaline oxides (such as CaO and SiO2) and sulfides react chemically with the slag trough refractory material at high temperatures, causing the lining material to gradually melt or peel off. Simultaneously, the fluidity of the molten slag creates continuous mechanical erosion within the channel, accelerating material loss. Frequent temperature fluctuations can also cause thermal stress cracks, and the adhesion of the solidified slag may alter the effective cross-section of the slag trough, affecting subsequent slag discharge efficiency.

[0004] In view of the above technical challenges, there is an urgent need to provide a new type of castable to improve its resistance to erosion, scour and service life, and to ensure the continuity of blast furnace smelting. Summary of the Invention

[0005] To address the problems existing in existing castables, this invention provides a blast furnace slag trench castable and its preparation method. By optimizing the raw material formula and preparation process, the high-temperature strength, erosion resistance, scour resistance and service life of the castable are significantly improved.

[0006] The solution adopted by this invention to solve its technical problem is: a blast furnace slag trench castable, wherein the mass percentages of each raw material component in the blast furnace slag trench castable are as follows: 6-9% brown fused alumina (15-8mm), 14-16% brown fused alumina (8-5mm), 17-19% brown fused alumina (5-3mm), 13-15% brown fused alumina (3-1mm), 8-11% dense fused alumina (1-0mm), 6-8% silicon carbide (1-0mm), and 200 The composition includes 8-12% silicon carbide, 3-5% zircon-silicon carbide composite powder, 6-8% alumina micropowder, 2-3% silica micropowder, 2-2.5% cement, 1-3% spherical asphalt, 0.5-2% carbon black, 0.2-0.5% boron carbide, 1-1.5% metallic silicon powder, 0.3-0.6% zirconium boride, 0.03-0.05% metallic aluminum powder, 0.05-0.08% organic fiber, and 0.1-0.2% water-reducing agent.

[0007] Furthermore, the mass percentages of each raw material component in the blast furnace slag trench castable are as follows: 8% brown fused alumina (15-8mm), 14% brown fused alumina (8-5mm), 18% brown fused alumina (5-3mm), 14% brown fused alumina (3-1mm), 10% dense fused alumina (1-0mm), 6% silicon carbide (1-0mm), 10% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 1% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent.

[0008] Further, the brown corundum contains Al2O3 ≥ 95 wt.%, SiO2 ≤ 0.9 wt.%, and Fe2O3 ≤ 0.25 wt.%; the dense corundum contains Al2O3 ≥ 99 wt.%, and Fe2O3 ≤ 0.1 wt.%; the silicon carbide contains SiC ≥ 97%, Fe2O3 ≤ 0.4%, and free carbon ≤ 0.5%; the alumina powder contains Al2O3 ≥ 99.5 wt.%; the silica powder contains SiO2 ≥ 95 wt.%; the cement contains Al2O3 ≥ 80 wt.%; and the spherical asphalt contains fixed carbon of... 55 wt.%, volatile matter ≤40 wt.%, ash content ≤0.5 wt.%; fixed carbon in carbon black ≥99.8 wt.%, volatile matter ≤1 wt.%, ash content ≤0.1 wt.%; boron carbide particle size is 325 mesh, B4C in boron carbide ≥95 wt.%; metallic silicon powder particle size is 325 mesh, Si in metallic silicon powder ≥98 wt.%; zirconium boride particle size <0.04 mm, ZrB2 content ≥94 wt.%; metallic aluminum powder particle size is 200 mesh, Al in metallic aluminum powder ≥99 wt.%.

[0009] Furthermore, the zircon-silicon carbide composite powder has a particle size of 800 mesh, wherein zircon powder accounts for 30% and silicon carbide powder accounts for 70%.

[0010] Furthermore, the water-reducing agent is a mixture of sodium tripolyphosphate and sodium hexametaphosphate.

[0011] This invention also provides a method for preparing blast furnace slag trench castable, comprising the following steps:

[0012] S1. Weigh out boron carbide, aluminum powder, zirconium boride, organic fiber and water-reducing agent according to mass percentage and put them into a container for stirring. After stirring evenly, use it as a small material.

[0013] S2. Weigh out brown corundum, silicon carbide, dense corundum, zircon-silicon carbide composite powder, alumina micro powder, silica micro powder, cement, spherical asphalt and carbon black of different particle sizes in sequence according to mass percentage, and pour them together with the small materials in the above steps into the mixer and mix evenly for 3 to 5 minutes. After packaging, the blast furnace slag trench castable can be obtained.

[0014] The present invention also provides a method for adding water to blast furnace slag trench castable, wherein the amount of water added during construction is 3.8 to 4.2% of the total mass of the blast furnace slag trench castable.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. Carbon materials, due to their high thermal conductivity and resistance to wetting by molten slag, are an indispensable component in castable refractory for iron troughs. Commonly used carbon raw materials include spherical asphalt, carbon black, and graphite. Spherical asphalt alone releases harmful gases as the temperature rises, thus polluting the environment. This invention adds carbon black to the raw materials to replace part of the spherical asphalt, which can reduce environmental pollution. Carbon black can fill the voids between aggregates, reduce porosity, and increase the density of the material, thereby enhancing wear resistance and impact resistance, while also improving the castable's resistance to slag erosion. In addition, because the oxygen-containing functional groups (such as carboxyl and hydroxyl groups) on the surface of carbon black can adsorb water-reducing agents (such as polycarboxylic acid systems) to form a stable dispersion system, it greatly improves the dispersibility of graphite and its wettability with water, thereby increasing the amount of carbon added and reducing the amount of water added, thus improving its workability.

[0017] 2. This invention introduces zircon-silicon carbide composite powder. Zircon decomposes into ZrO2 and SiO2 at high temperature. The SiC surface is oxidized to form a SiO2 film. ZrO2 reacts with the SiO2 film to produce a high-melting-point glass phase, which fills the pores and hinders the erosion of oxygen and slag, thereby improving the slag erosion resistance of the castable. ZrO2 undergoes a tetragonal-monoclinic phase transformation at high temperature, accompanied by a certain volume expansion, which slows down the formation of cracks under thermal cycling and improves the toughness and thermal shock stability of the castable.

[0018] 3. By introducing zirconium boride, the present invention oxidizes metallic silicon to generate SiO2 at high temperature, which forms a B2O3-SiO2-ZrO2 composite glass phase with B2O3 decomposed from ZrB2. This phase can fill the pores and improve the oxidation resistance of the slag trench castable.

[0019] 4. The blast furnace slag trench castable and its preparation method provided by this invention, after laboratory performance testing, show that the room temperature flexural strength and room temperature compressive strength of the blast furnace slag trench castable meet the performance indicators, and it has excellent resistance to slag erosion, scour, and oxidation. The application of this invention improves the service life of blast furnace slag trenches, reduces the labor intensity of workers, and lowers costs, thus having certain practical significance.

[0020] In summary, this invention improves the oxidation resistance, slag erosion resistance, and scouring resistance of blast furnace slag trench castable by using carbon black, zircon-silicon carbide composite powder, and zirconium boride as raw materials, thereby reducing costs and extending service life. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a technical solution for blast furnace slag trench castable and its preparation method:

[0023] A blast furnace slag trench castable, comprising the following raw material components by mass percentage: 6-9% brown fused alumina (15-8mm), 14-16% brown fused alumina (8-5mm), 17-19% brown fused alumina (5-3mm), 13-15% brown fused alumina (3-1mm), 8-11% dense fused alumina (1-0mm), 6-8% silicon carbide (1-0mm), 8-12% 200-mesh silicon carbide, 3-5% zircon-silicon carbide composite powder, 6-8% alumina micropowder, 2-3% silica micropowder, 2-2.5% cement, 1-3% spherical asphalt, 0.5-2% carbon black, 0.2-0.5% boron carbide, 1-1.5% metallic silicon powder, 0.3-0.6% zirconium boride, 0.03-0.05% metallic aluminum powder, 0.05-0.08% organic fiber, and 0.1-0.2% water-reducing agent.

[0024] This invention introduces 200-mesh silicon carbide, which (approximately 75 μm in particle size) is a fine powder raw material that can fill the voids between aggregates (such as brown corundum and dense corundum), reduce apparent porosity, and increase material density. At high temperatures, the silicon carbide surface oxidizes to form liquid-phase SiO2, which reacts with alumina micropowder to form an interleaved needle-like mullite crystal phase. This structure can compensate for matrix linear shrinkage, enhance the bonding strength between the matrix and aggregate, and improve thermal shock resistance. The SiO2 film generated by silicon carbide oxidation can cover the material surface, inhibit oxygen diffusion, and slow down the oxidation process.

[0025] This invention introduces zircon-silicon carbide composite powder. Zircon decomposes at high temperature into ZrO2 and SiO2. The SiC surface oxidizes to form a SiO2 film. ZrO2 reacts with the SiO2 film to produce a high-melting-point glassy phase, filling pores and hindering the erosion of oxygen and slag, thus improving the slag erosion resistance of the castable. ZrO2 can also react with CaO in the slag to form a ZrO2-CaO-SiO2 composite phase, further enhancing erosion resistance. ZrO2 has a phase transformation toughening mechanism at high temperatures. When the temperature changes, ZrO2 undergoes a tetragonal-to-monoclinic phase transformation, accompanied by a certain volume expansion, which slows down the formation of cracks under thermal cycling and improves the toughness and thermal shock stability of the castable. At the same time, the SiC particles in the zircon-silicon carbide composite powder have high hardness, which can significantly improve the wear resistance of the material surface, further improving the erosion resistance of the castable and extending its service life.

[0026] The 200-mesh silicon carbide filler material reduces apparent porosity. Simultaneously, the SiO2 film generated by its oxidation synergistically interacts with the SiO2 from zircon decomposition to form a denser glassy protective layer, significantly improving oxidation resistance. Together, they reduce slag penetration paths. The ZrO2 from zircon and the SiC from silicon carbide form a "hard skeleton-glassy phase" double-layer protective structure, improving slag penetration resistance by over 20%. Furthermore, boron carbide increases the medium-temperature strength of the castable at 1000℃. The B2O3 generated by boron carbide synergistically interacts with the SiO2 from zircon to optimize the B2O3-SiO2-ZrO2 glassy phase structure, improving thermal shock resistance. The combined effect of boron carbide and zircon reduces the strength difference between medium and high temperatures, preventing crack propagation caused by thermal stress and thus inhibiting slag penetration.

[0027] This invention introduces zirconium boride. At high temperatures, metallic silicon oxidizes to generate SiO2, which combines with B2O3 from the decomposition of ZrB2 to form a B2O3-SiO2-ZrO2 composite glass phase. This phase fills pores and improves the oxidation resistance of the slag trench castable. In addition, B2O3 and SiO2 react at high temperatures to form a high-viscosity borosilicate glass. The borosilicate glass phase has excellent fluidity (effectively sealing pores and cracks) and extremely high chemical stability, which can resist the erosion of various high-temperature slags. This provides the castable with a strong self-healing and oxidation-resistant barrier, greatly extending the service life of the castable.

[0028] The ZrO2 and SiO2 (forming a liquid phase) generated by the high-temperature decomposition of zircon-silicon carbide composite powder can effectively wet and adhere to molten slag, forming a high-viscosity barrier layer that slows down slag penetration and erosion. The SiC in it also provides slag resistance. Zirconium boride has extremely high melting point, hardness, chemical inertness (especially for acidic / neutral slags) and excellent thermal conductivity, which can directly block molten slag, especially showing good resistance to slags containing corrosive components such as iron and manganese. Both ZrO2 and ZrB2 are rich in zirconium, which allows them to form a more stable and denser zirconium-rich protective layer or reaction layer on or near the surface of the material under high-temperature conditions. This can greatly enhance the ability to resist the dissolution and penetration of blast furnace slag. The ultra-high hardness of ZrB2 also enhances the wear resistance of this area.

[0029] In a preferred embodiment of the present invention, brown corundum contains Al2O3 ≥ 95 wt.%, SiO2 ≤ 0.9 wt.%, and Fe2O3 ≤ 0.25 wt.%; dense corundum contains Al2O3 ≥ 99 wt.%, and Fe2O3 ≤ 0.1 wt.%; silicon carbide contains SiC ≥ 97%, Fe2O3 ≤ 0.4%, and free carbon ≤ 0.5%; alumina micro powder contains Al2O3 ≥ 99.5 wt.%; silica micro powder contains SiO2 ≥ 95 wt.%; cement contains Al2O3 ≥ 80 wt.%; and spherical asphalt contains... The fixed carbon content is 55 wt.%, volatile matter ≤40 wt.%, and ash content ≤0.5 wt.%; the fixed carbon content in carbon black is ≥99.8 wt.%, volatile matter ≤1 wt.%, and ash content ≤0.1 wt.%; the particle size of boron carbide is 325 mesh, and B4C content in boron carbide is ≥95 wt.%; the particle size of metallic silicon powder is 325 mesh, and Si content in metallic silicon powder is ≥98 wt.%; the particle size of zirconium boride is <0.04 mm, and ZrB2 content is ≥94 wt.%; the particle size of metallic aluminum powder is 200 mesh, and Al content in metallic aluminum powder is ≥99 wt.%.

[0030] In this invention, the carbon black is selected with high fixed carbon content. The high fixed carbon content can ensure that the carbon black maintains a stable carbon structure at high temperature and reduce the interference of non-carbon components (such as ash and volatile matter), thereby enhancing the anti-slag and anti-oxidation properties. The carbon black is selected with low volatile matter and ash content. The low volatile matter and ash content together reduce gas generation and impurity melting at high temperature, avoid internal defects in the material, and improve structural density and durability.

[0031] Using 325-mesh metallic silicon powder can significantly improve material performance: its fine particle size brings high specific surface area and reactivity, which can quickly react with oxygen to form a dense SiO2 / SiC protective layer, effectively enhancing oxidation resistance; at the same time, it reduces apparent porosity by filling pores, reducing slag penetration, and combined with the mullite and glass phase filling structure formed by reacting with Al2O3, it greatly improves slag erosion resistance and high-temperature strength; in addition, the uniform particle size distribution optimizes the flowability of the castable, making it easier to construct and vibrate, thus comprehensively achieving a synergistic improvement in material density, erosion resistance and workability.

[0032] In a preferred embodiment of the present invention, the zircon-silicon carbide composite powder has a particle size of 800 mesh, wherein zircon powder accounts for 30% and silicon carbide powder accounts for 70%.

[0033] This invention utilizes 800-mesh zircon-silicon carbide composite powder, which effectively fills the pores between coarse particles (e.g., 15-8mm brown fused alumina) and intermediate particles (e.g., 5-3mm brown fused alumina) in castables, forming a dense packing structure. Simultaneously, the 800-mesh particle size ensures uniform dispersion of zircon and silicon carbide in the matrix, avoiding localized component segregation and thus improving material performance consistency. The fine powder has a large specific surface area, accelerating the decomposition of zircon (ZrSiO4) at high temperatures to generate ZrO2 and SiO2, rapidly forming a high-melting-point protective layer. Furthermore, the 800-mesh fine powder fills particle gaps, reducing frictional resistance and lowering castable viscosity. The synergistic effect of the composite powder and water-reducing agent further reduces water addition while maintaining good fluidity and improving workability. Castables prepared with composite powder containing 30% zircon and 70% silicon carbide exhibit significantly improved slag erosion resistance compared to single silicon carbide materials. Furthermore, this ratio effectively reduces production costs.

[0034] In a preferred embodiment of the present invention, the water-reducing agent is a mixture of sodium tripolyphosphate and sodium hexametaphosphate.

[0035] This invention uses a mixture of sodium tripolyphosphate and sodium hexametaphosphate as a water-reducing agent. Sodium tripolyphosphate rapidly reduces the surface tension of the slurry and minimizes water loss, while sodium hexametaphosphate continuously releases free water through ion chelation and enhances electrostatic repulsion of particles. The combination of the two enables the slurry to achieve high fluidity with low water addition, meeting pumping requirements. Simultaneously, sodium tripolyphosphate fills micropores and inhibits alkali-aggregate reaction, while sodium hexametaphosphate optimizes particle packing and reduces drying shrinkage, synergistically improving material density and enhancing crack resistance and durability. Furthermore, the water reduction rate of the mixed water-reducing agent reaches 15%-20%, which is superior to that of a single component. Moreover, performance and cost can be balanced by adjusting the ratio, ultimately achieving comprehensive optimization of fluidity, strength, erosion resistance, and economy.

[0036] This invention also provides a method for preparing blast furnace slag trench castable, comprising the following steps:

[0037] S1. Weigh out boron carbide, aluminum powder, zirconium boride, organic fiber and water-reducing agent according to mass percentage and put them into a container for stirring. After stirring evenly, use it as a small material.

[0038] S2. Weigh out brown corundum, silicon carbide, dense corundum, zircon-silicon carbide composite powder, alumina micro powder, silica micro powder, cement, spherical asphalt and carbon black of different particle sizes in sequence according to mass percentage, and pour them together with the small materials in the above steps into the mixer and mix evenly for 3 to 5 minutes. After packaging, the blast furnace slag trench castable can be obtained.

[0039] The preparation method of this invention adopts a two-step sequential addition approach, aiming to comprehensively improve the overall performance of the material through core mechanisms such as component functional differentiation, reactivity matching, mixing uniformity optimization, and construction performance control. The first step involves premixing minor components such as boron carbide, aluminum powder, zirconium boride, organic fibers, and water-reducing agents to ensure the stable formation of the antioxidant system, uniform dispersion of the high-temperature stabilizer, effective protection of the anti-burst fibers, and pre-adsorption of the water-reducing agent to optimize flowability. The second step involves adding the main material in the order of coarse particles, intermediate particles, fine powder, binder, and finally minor components, achieving dense packing and optimized gradation while preventing functional components from being encapsulated or deactivated. This process significantly improves the antioxidant properties, high-temperature stability, density, flowability, and thermal shock resistance of the castable, and effectively protects the activity of the organic fibers and binder, providing a reliable guarantee for long-term service under high-temperature conditions.

[0040] The present invention also provides a method for adding water to blast furnace slag trench castable, wherein the amount of water added during construction is 3.8 to 4.2% of the total mass of the blast furnace slag trench castable.

[0041] Specific implementation examples:

[0042] The following provides a specific embodiment of the blast furnace slag trench castable and its preparation method according to the present invention.

[0043] Example 1:

[0044] This embodiment provides a blast furnace slag trench castable, with the following mass percentages of raw material components: 8% brown fused alumina (15-8mm), 14% brown fused alumina (8-5mm), 18% brown fused alumina (5-3mm), 14% brown fused alumina (3-1mm), 10% dense fused alumina (1-0mm), 6% silicon carbide (1-0mm), 10% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 1% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent.

[0045] Based on the above-mentioned blast furnace slag trench castable, the present invention also provides a method for preparing blast furnace slag trench castable, comprising the following steps:

[0046] S1. Weigh out boron carbide, aluminum powder, zirconium boride, organic fiber and water-reducing agent according to mass percentage and put them into a container for stirring. After stirring evenly, use it as a small material.

[0047] S2. Weigh out brown corundum, silicon carbide, dense corundum, zircon-silicon carbide composite powder, alumina micro powder, silica micro powder, cement, spherical asphalt and carbon black of different particle sizes in sequence according to mass percentage, and pour them together with the small materials in the above steps into the mixer and mix evenly for 3 to 5 minutes. After packaging, the blast furnace slag trench castable can be obtained.

[0048] Example 2:

[0049] This embodiment provides a blast furnace slag trench castable with the following mass percentages of raw material components: 6% brown fused alumina (15-8mm), 16% brown fused alumina (8-5mm), 18% brown fused alumina (5-3mm), 14% brown fused alumina (3-1mm), 8% dense corundum (1-0mm), 6% silicon carbide (1-0mm), 11% 200-mesh silicon carbide, 4% zircon-silicon carbide composite powder, 7% alumina micropowder, 2.5% silica micropowder, 2% cement, 2% spherical asphalt, 0.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.6% zirconium boride, 0.03% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of the above-mentioned blast furnace slag trench castable is the same as in Example 1.

[0050] Example 3:

[0051] This embodiment provides a blast furnace slag trench castable with the following mass percentages of raw material components: 9% brown fused alumina (15-8mm), 14.5% brown fused alumina (8-5mm), 17% brown fused alumina (5-3mm), 15% brown fused alumina (3-1mm), 11% dense corundum (1-0mm), 7% silicon carbide (1-0mm), 11% 200-mesh silicon carbide, 3% zircon-silicon carbide composite powder, 6% alumina micropowder, 3% silica micropowder, 2% cement, 3% spherical asphalt, 2% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.3% zirconium boride, 0.04% metallic aluminum powder, 0.05% organic fiber, and 0.2% water-reducing agent. The preparation method of the above-mentioned blast furnace slag trench castable is the same as in Example 1.

[0052] Example 4:

[0053] This embodiment provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8.5% brown fused alumina (15-8mm), 15% brown fused alumina (8-5mm), 17% brown fused alumina (5-3mm), 14.5% brown fused alumina (3-1mm), 10.5% dense corundum (1-0mm), 6.5% silicon carbide (1-0mm), 11% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 7.5% alumina micropowder, 2% silica micropowder, 2.5% cement, 1% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.08% organic fiber, and 0.2% water-reducing agent. The preparation method of the above-mentioned blast furnace slag trench castable is the same as in Example 1.

[0054] Example 5:

[0055] This embodiment provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8% brown fused alumina (15-8mm), 14.5% brown fused alumina (8-5mm), 19% brown fused alumina (5-3mm), 15% brown fused alumina (3-1mm), 10% dense fused alumina (1-0mm), 8% silicon carbide (1-0mm), 10% 200-mesh silicon carbide, 4% zircon-silicon carbide composite powder, 7% alumina micropowder, 2% silica micropowder, 2% cement, 2% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.1% water-reducing agent. The preparation method of the above-mentioned blast furnace slag trench castable is the same as in Example 1.

[0056] Example 6:

[0057] This embodiment provides a blast furnace slag trench castable with the following mass percentages of raw material components: 7.5% brown fused alumina (15-8mm), 15% brown fused alumina (8-5mm), 19% brown fused alumina (5-3mm), 13% brown fused alumina (3-1mm), 9% dense fused alumina (1-0mm), 8% silicon carbide (1-0mm), 11.5% 200-mesh silicon carbide, 3% zircon-silicon carbide composite powder, 8% alumina micropowder, 2% silica micropowder, 2% cement, 1% spherical asphalt, 1.5% carbon black, 0.5% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.05% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of the above-mentioned blast furnace slag trench castable is the same as in Example 1.

[0058] Comparative Example 1:

[0059] This comparative example provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8% brown fused alumina (15-8 mm), 14% brown fused alumina (8-5 mm), 18% brown fused alumina (5-3 mm), 14% brown fused alumina (3-1 mm), 10% dense corundum (1-0 mm), 6% silicon carbide (1-0 mm), 10% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 2.5% spherical asphalt, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of this blast furnace slag trench castable is the same as in Example 1, except that this comparative example does not contain carbon black.

[0060] Comparative Example 2:

[0061] This comparative example provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8% brown fused alumina (15-8 mm), 14% brown fused alumina (8-5 mm), 18% brown fused alumina (5-3 mm), 14% brown fused alumina (3-1 mm), 10% dense corundum (1-0 mm), 6% silicon carbide (1-0 mm), 10% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 1% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of this blast furnace slag trench castable is the same as in Example 1, except that the metallic silicon powder in this comparative example is added in 400-mesh form.

[0062] Comparative Example 3:

[0063] This comparative example provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8% brown fused alumina (15-8 mm), 14% brown fused alumina (8-5 mm), 18% brown fused alumina (5-3 mm), 14% brown fused alumina (3-1 mm), 10% dense corundum (1-0 mm), 6% silicon carbide (1-0 mm), 10% 200-mesh silicon carbide, 5.5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 2.5% spherical asphalt, 0.2% boron carbide, 1.5% metallic silicon powder, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of this blast furnace slag trench castable is the same as in Example 1, except that this comparative example does not contain zirconium boride.

[0064] Comparative Example 4:

[0065] This comparative example provides a blast furnace slag trench castable with the following mass percentages of raw material components: 8% brown fused alumina (15-8 mm), 14% brown fused alumina (8-5 mm), 18% brown fused alumina (5-3 mm), 14% brown fused alumina (3-1 mm), 10% dense corundum (1-0 mm), 6% silicon carbide (1-0 mm), 10% 200-mesh silicon carbide, 6% alumina powder, 2% silica powder, 2% cement, 2.5% spherical asphalt, 0.2% boron carbide, 1.5% metallic silicon powder, 5.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent. The preparation method of this blast furnace slag trench castable is the same as in Example 1, except that this comparative example does not contain zircon-silicon carbide composite powder.

[0066] The present invention conducts product qualification performance tests on blast furnace slag trench castables prepared with different proportions in Examples 1-6 and Comparative Examples 1-4. The test methods are as follows:

[0067] The permanent linear shrinkage rate was tested according to GB / T 5988-2022; the room temperature flexural strength was tested according to GB / T 3001-2017; the room temperature compressive strength was tested according to GB / T 5072-2023; the high temperature flexural strength was tested according to GB / T 3002-2017; the bulk density was tested according to GB / T 2997-2015; the slag erosion resistance was tested according to GB / T 8931-2007; the performance test results are shown in Table 1.

[0068] Table 1. Test results of Examples 1-6 and Comparative Examples 1-4

[0069]

[0070] Comparative Example 1 is based on Example 1, except that carbon black is removed and spherical asphalt is added accordingly. As can be seen from Table 1, compared with Example 1, the bulk density of Comparative Example 1 is reduced, the linear change rate is significantly increased, the flexural strength and compressive strength are significantly reduced, and the erosion rate is also increased, which is significantly lower than the test results of Example 1.

[0071] Comparative Example 2 is based on Example 1, with the addition of silicon metal powder in the form of 400 mesh. As can be seen from Table 1, compared with Example 1, Comparative Example 2 has a lower bulk density, a significantly higher linear change rate, a significantly lower flexural strength and compressive strength, and a faster erosion rate, which is significantly lower than the test results of Example 1.

[0072] Comparative Example 3 is based on Example 1, but without the addition of zircon boride and with the addition of zircon-silicon carbide composite powder. As can be seen from Table 1, compared with Example 1, Comparative Example 3 has a lower bulk density, a significantly higher linear change rate, a significantly lower flexural strength and compressive strength, and a significantly faster erosion rate, which is significantly lower than the test results of Example 1.

[0073] Comparative Example 4 is based on Example 1, but the addition of zircon-silicon carbide composite powder is omitted and zirconium boride is added accordingly. As can be seen from Table 1, compared with Example 1, Comparative Example 4 has a lower bulk density, a significantly higher linear change rate, a significantly lower flexural strength and compressive strength, and a significantly faster erosion rate, which is significantly lower than the test results of Example 1.

[0074] In summary, both zircon-silicon carbide composite powder and zirconium boride, being rich in zirconium, can form a more stable and dense zirconium-rich protective layer at high temperatures, enhancing resistance to slag dissolution and penetration. Simultaneously, the ultra-high hardness of ZrB2 improves regional wear resistance. Furthermore, the introduction of carbon black, combined with spherical asphalt, reduces environmental pollution. Carbon black fills voids between aggregates, reducing porosity and increasing material density, thereby enhancing wear resistance and impact resistance, while also improving the castable's resistance to slag erosion. 325-mesh metallic silicon powder further improves the castable's density, high-temperature strength, and erosion resistance. In addition, through scientific formulation design and synergistic effects, the various raw materials can effectively improve the castable's flexural strength, oxidation resistance, slag erosion resistance, and service life while maintaining their original properties.

[0075] The above description is only a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A blast furnace slag trench castable, used in blast furnace slag trenches, characterized in that: The mass percentages of each raw material component in the blast furnace slag trough castable are as follows: 6-9% brown fused alumina (15-8mm), 14-16% brown fused alumina (8-5mm), 17-19% brown fused alumina (5-3mm), 13-15% brown fused alumina (3-1mm), 8-11% dense fused alumina (1-0mm), 6-8% silicon carbide (1-0mm), 8-12% 200-mesh silicon carbide, 3-5% zircon-silicon carbide composite powder, 6-8% alumina micropowder, 2-3% silica micropowder, 2-2.5% cement, 1-3% spherical asphalt, 0.5-2% carbon black, 0.2-0.5% boron carbide, 1-1.5% metallic silicon powder, 0.3-0.6% zirconium boride, 0.03-0.05% metallic aluminum powder, 0.05-0.08% organic fiber, and 0.1-0.2% water-reducing agent.

2. The blast furnace slag trench castable according to claim 1, characterized in that: The mass percentages of each raw material component in the blast furnace slag trench castable are as follows: 8% brown fused alumina (15-8mm), 14% brown fused alumina (8-5mm), 18% brown fused alumina (5-3mm), 14% brown fused alumina (3-1mm), 10% dense fused alumina (1-0mm), 6% silicon carbide (1-0mm), 10% 200-mesh silicon carbide, 5% zircon-silicon carbide composite powder, 6% alumina micropowder, 2% silica micropowder, 2% cement, 1% spherical asphalt, 1.5% carbon black, 0.2% boron carbide, 1.5% metallic silicon powder, 0.5% zirconium boride, 0.04% metallic aluminum powder, 0.06% organic fiber, and 0.2% water-reducing agent.

3. The blast furnace slag trench castable according to claim 1, characterized in that: The brown fused alumina contains Al₂O₃ ≥ 95 wt.%, SiO₂ ≤ 0.9 wt.%, and Fe₂O₃ ≤ 0.25 wt.%; dense fused alumina contains Al₂O₃ ≥ 99 wt.%, and Fe₂O₃ ≤ 0.1 wt.%; silicon carbide contains SiC ≥ 97%, Fe₂O₃ ≤ 0.4%, and free carbon ≤ 0.5%; alumina micropowder contains Al₂O₃ ≥ 99.5 wt.%; silica micropowder contains SiO₂ ≥ 95 wt.%; cement contains Al₂O₃ ≥ 80 wt.%; and spherical asphalt contains 55% fixed carbon. wt.%, volatile matter ≤40wt.%, ash ≤0.5wt.%; fixed carbon in carbon black ≥99.8wt.%, volatile matter ≤1wt.%, ash ≤0.1wt.%; boron carbide particle size is 325 mesh, B4C in boron carbide ≥95wt.%; metallic silicon powder particle size is 325 mesh, Si in metallic silicon powder ≥98wt.%; zirconium boride particle size <0.04mm, ZrB2 content ≥94wt.%; metallic aluminum powder particle size is 200 mesh, Al in metallic aluminum powder ≥99wt.%.

4. The blast furnace slag trench castable according to claim 1, characterized in that: The zircon-silicon carbide composite powder has a particle size of 800 mesh, of which zircon powder accounts for 30% and silicon carbide powder accounts for 70%.

5. The blast furnace slag trench castable according to claim 1, characterized in that: The water-reducing agent is a mixture of sodium tripolyphosphate and sodium hexametaphosphate.

6. A method for preparing a blast furnace slag trench castable according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Weigh out boron carbide, aluminum powder, zirconium boride, organic fiber and water-reducing agent according to mass percentage and put them into a container for stirring. After stirring evenly, use it as a small material. S2. Weigh out brown corundum, silicon carbide, dense corundum, zircon-silicon carbide composite powder, alumina micro powder, silica micro powder, cement, spherical asphalt and carbon black of different particle sizes in sequence according to mass percentage, and pour them together with the small materials in the above steps into the mixer and mix evenly for 3 to 5 minutes. After packaging, the blast furnace slag trench castable can be obtained.

7. A method for adding water to blast furnace slag trench castable according to any one of claims 1-5, characterized in that: The amount of water added during construction is 3.8% to 4.2% of the total mass of the blast furnace slag trench castable.

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