Alumina suspension calcining furnace wear-resistant castable and its casting method

Abstract

The application relates to a wear-resistant castable for an alumina suspension calcination furnace, which comprises the following raw materials in mass fractions: pretreated corundum aggregate 30-45 parts, silicon nitride particles 16-26 parts, nano silicon nitride powder 6-12 parts, silicon powder 2-3 parts, alpha-Al2O3 micro powder 6-8 parts, yttrium stabilized zirconium micro powder 1-3 parts, NiCr 13 Al4Ti 0.5 alloy powder 1-3 parts, anti-explosion fiber 0.1-0.15 parts, binder 8-15 parts and water reducing agent 0.1-0.2 parts. The open porosity is low, the erosion of alkaline substances can be prevented, and the wear resistance and thermal shock resistance are good.

Description

Technical Field

[0001] This invention belongs to the field of refractory ceramics technology, specifically relating to a wear-resistant castable for an alumina suspension calcining furnace and its casting method. Background Technology

[0002] The alumina suspension roasting furnace is based on fluidization technology, which allows solid aluminum hydroxide particles to be suspended in a high-temperature gas flow. In this state, the material is in full contact with the high-temperature flue gas, achieving efficient heat and mass transfer.

[0003] Castable refractory materials are extensively used in the lining of alumina suspension calcination furnaces to cope with complex operating conditions. However, in actual operation, castable refractory materials often exhibit defects such as cracking, spalling, pulverization, and even collapse. The main reasons can be summarized as follows: insufficient thermal stress impact and thermal shock stability, and high-speed airflow erosion and wear.

[0004] The alumina production environment contains a large amount of alkaline substances (such as Na₂O and K₂O). At high temperatures, these alkali metal oxides can penetrate into the pores and microcracks of the castable in the form of steam or molten salt. The alkali reacts chemically with the matrix components in the castable, such as silicate-bound phases, and even impurities in high-alumina aggregates, to form low-melting-point compounds, such as β-alumina and potassium-sodium feldspar, or to cause volume expansion, such as the formation of nepheline. During start-up and shutdown, load fluctuations, or unstable local combustion in the suspension roasting furnace, the furnace temperature undergoes drastic changes. If the castable's thermal shock resistance, i.e., its resistance to rapid heating and cooling, is poor, frequent temperature fluctuations will generate enormous thermal stress. When the stress exceeds the material's strength limit, it will trigger network cracks, leading to flaky surface peeling. To maintain material suspension, the airflow velocity inside the furnace is extremely high. The high-speed airflow containing hard alumina particles exerts a continuous cutting and scouring effect on the surface of the castable. If the castable refractory lacks sufficient alkali resistance and abrasion resistance, or if the construction surface is uneven and generates eddies, it will accelerate the thinning of the lining, eventually leading to localized penetration or detachment. All of these factors will result in a short service life for the alumina suspension roasting furnace and increased maintenance costs. Summary of the Invention

[0005] The purpose of this invention is to provide a wear-resistant castable for alumina suspension roasting furnaces, so as to solve the technical problems of short service life and high maintenance cost of existing alumina suspension roasting furnaces.

[0006] Another object of the present invention is to provide a casting method for wear-resistant castables for alumina suspension calcining furnaces.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A wear-resistant castable for an alumina suspension calcining furnace comprises the following raw materials in parts by weight: Pretreated corundum aggregate 30-45 parts, silicon nitride particles 16-26 parts, nano-silicon nitride powder 6-12 parts by weight, silicon powder 2-3 parts, α-Al₂O₃ micro powder 6-8 parts, yttrium-stabilized zirconium oxide micro powder 1-3 parts, NiCr 13 Al4Ti 0.5 The alloy powder consists of 1-3 parts, explosion-proof fiber of 0.1-0.15 parts, binder of 8-15 parts, and water-reducing agent of 0.1-0.2 parts.

[0008] Furthermore, the casting method for the yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of mixed solution: Dissolve zirconium source and yttrium source in water to form a mixed solution, and then add 2-3% of dispersant by mass of the mixed solution; S2, Prepare the precipitant solution: Dissolve the precipitant in water to form a precipitant solution; S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution and mixed. During the mixing process, the mixture is stirred at high speed at 40-60℃, and the pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at high speed at 40-60℃ for 0.5-2 hours. S4, Aging: After the reaction is complete, aging is carried out with slow stirring for 1 to 4 hours; S5, Post-processing: After aging, filter and wash until chloride ions are no longer detectable, then dry to obtain yttrium-stabilized zirconia micro powder as a preliminary product; S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

[0009] Furthermore, the yttrium salt is yttrium oxide, the zirconium source is zirconium oxide, the molar ratio of zirconium source to yttrium source in the mixed solution is 1:1 to 1:1.5, and the total molar concentration of zirconium source and yttrium source in the mixed solution is 2 to 3 mol / L.

[0010] Furthermore, the dispersant is polyethylene glycol 600, the precipitant is ammonium bicarbonate, and the molar amount of the precipitant is 3.6 to 4 times the total molar amount of the zirconium source and the yttrium source.

[0011] Furthermore, the NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 part by mass of Ni metal powder, 13 parts by mass of Cr metal powder, 4 parts by mass of Al metal powder, and 0.5 parts by mass of Ti metal powder, respectively place them in anhydrous ethanol and ultrasonically clean for 10-20 minutes. After drying, mix them evenly and melt them in a vacuum melting furnace at 2500-3000℃ for 30-60 minutes to obtain the initial alloy product. S2, the initial alloy sample is placed in a muffle furnace and homogenized at 1100–1150℃ for 90–120 min. After cooling, it is hot-rolled at 850–900℃ for 3–5 passes, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample is then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0012] Further, the pretreated corundum aggregate includes 12-18 parts by weight of pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, 10-15 parts by weight of pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and 8-12 parts by weight of pretreated fused white corundum aggregate with a particle size of 3-1 mm; a silicon nitride suspension with a solid content of 15-18% is prepared, and the 8-5 mm tabular corundum coarse aggregate and the 5-3 mm tabular corundum medium aggregate are then mixed together. The raw materials and fused white corundum aggregates with a particle size of 3-1 mm were vacuum impregnated in a silicon nitride particle suspension, dried at 100-120℃, and then heated at 800-900℃ for 2-3 hours in a N2 atmosphere to obtain pretreated tabular corundum coarse aggregates with a particle size of 8-5 mm, pretreated tabular corundum medium aggregates with a particle size of 5-3 mm, and pretreated fused white corundum aggregates with a particle size of 3-1 mm. After mixing, the pretreated corundum aggregates were obtained.

[0013] Furthermore, the silicon nitride particles comprise 10-16 parts by weight of silicon nitride particles with a particle size of 5-3 mm and 6-10 parts by weight of silicon nitride particles with a particle size of 3-1 mm.

[0014] Furthermore, the NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm.

[0015] Furthermore, the binder is calcium aluminate cement, and the length of the explosion-proof fiber is 15-25 mm.

[0016] The casting method for wear-resistant castables used in alumina suspension calcining furnaces includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 4-5 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 6-8 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 8-10 hours, and increase the temperature to 1450℃ at 30℃ / h and hold for 6-10 hours.

[0017] The beneficial effects of this invention are: The wear-resistant castable for alumina suspension calcining furnace of this invention features pretreated corundum aggregate with low open porosity to prevent corrosion by alkaline substances. Nano-sized silicon nitride particles fill the gaps between the modified corundum aggregate and silicon nitride particles, forming a "nano-millimeter" composite structure. These nanoparticles hinder dislocation movement, forcing crack propagation to bypass them, resulting in high density and structural stability. Silicon powder and silicon nitride form a Si₂N₂O bond phase in situ at high temperatures, exhibiting excellent thermal shock resistance. α-Al₂O₃ micropowder forms a dense Al₂O₃ film at high temperatures, increasing the wear resistance of the alumina suspension calcining furnace castable. Yttrium-stabilized zirconia micropowder and NiCr... 13 Al4Ti 0.5 Alloy powder can form a dense protective film at high temperatures, increasing the alkali resistance and wear resistance of the alumina suspension calcining furnace castable. Explosion-proof fibers can improve the thermal shock resistance of the alumina suspension calcining furnace. Attached Figure Description

[0018] Figure 1 The images show the wear resistance of the alumina suspension calcining furnace wear-resistant castables used in Examples 1-3 and Comparative Examples 1-4 after wear resistance performance testing. Detailed Implementation

[0019] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0020] Example 1 The wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following raw materials: Pretreated corundum aggregate 37kg, silicon nitride particles 21kg, nano silicon nitride powder 8kg, silicon powder 2kg, α-Al₂O₃ micro powder 8kg, yttrium-stabilized zirconium oxide micro powder 2kg, NiCr 13 Al4Ti 0.52 kg of alloy powder, 0.1 kg of explosion-proof fiber, 12 kg of binder, 0.2 kg of water-reducing agent, and 3 kg of water.

[0021] The pretreated corundum aggregate includes 15 kg of pretreated tabular corundum coarse aggregate with a particle size of 8–5 mm, 12 kg of pretreated tabular corundum medium aggregate with a particle size of 5–3 mm, and 10 kg of pretreated fused white corundum aggregate with a particle size of 3–1 mm. A silicon nitride suspension with a solid content of 18% is prepared. The 8–5 mm tabular corundum coarse aggregate, 5–3 mm tabular corundum medium aggregate, and 3–1 mm fused white corundum aggregate are vacuum impregnated in the silicon nitride particle suspension, dried at 120°C, and then heated at 100°C for 2 hours in a N2 atmosphere to obtain the 8–5 mm pretreated tabular corundum coarse aggregate, 5–3 mm pretreated tabular corundum medium aggregate, and 3–1 mm pretreated fused white corundum aggregate. These are then mixed to obtain the pretreated corundum aggregate.

[0022] The silicon nitride particles include 13 kg of silicon nitride particles with a particle size of 5-3 mm and 8 kg of silicon nitride particles with a particle size of 3-1 mm.

[0023] NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm. The binder is calcium aluminate cement, the water-reducing agent is polycarboxylate water-reducing agent, and the length of the explosion-proof fiber is 15-25mm.

[0024] The casting method for yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of the mixed solution: Dissolve zirconium oxide and yttrium oxide in water to form a mixed solution, then add 3% (by mass) of polyethylene glycol 600 dispersant to the mixed solution. The molar ratio of zirconium oxide to yttrium oxide in the mixed solution is 1:1.5. The total molar concentration of zirconium oxide and yttrium oxide in the mixed solution is 2.5 mol / L.

[0025] S2, Prepare the precipitant solution: Dissolve the precipitant ammonium bicarbonate in water to form a precipitant solution; the molar amount of the precipitant is 3.6 times the total molar amount of zirconium oxide and yttrium oxide.

[0026] S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution for mixing. The mixing process is carried out at 50°C with high-speed stirring at a speed of 3000 r / min. The pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at 50°C for 1 hour at a speed of 3000 r / min.

[0027] S4, Aging: After the reaction is complete, aging is carried out by slow stirring for 2 hours at a stirring speed of 60 r / min.

[0028] S5, Post-processing: After aging, filter and wash until no chloride ions can be detected, then dry to obtain yttrium-stabilized zirconia micro powder as the initial product.

[0029] S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

[0030] NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 kg of Ni metal powder, 13 kg of Cr metal powder, 4 kg of Al metal powder, and 0.5 kg of Ti metal powder, respectively, and ultrasonically clean them in anhydrous ethanol for 20 min. After drying, mix them evenly and melt them in a vacuum melting furnace at 2500℃ for 60 min to obtain the initial alloy product.

[0031] S2, the initial alloy sample was placed in a muffle furnace and homogenized at 1100–1150°C for 120 min. After cooling, it was hot-rolled five times at 900°C, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample was then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0032] The casting method of the wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 4 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 8 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 8 hours, increase the temperature to 1450℃ at 30℃ / h and hold for 10 hours.

[0033] Example 2 The wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following raw materials: Pretreated corundum aggregate 38kg, silicon nitride particles 24kg, nano-silicon nitride powder 10kg, silicon powder 2kg, α-Al₂O₃ micro powder 7kg, yttrium-stabilized zirconium oxide micro powder 3kg, NiCr 13 Al4Ti 0.5 1 kg of alloy powder, 0.15 kg of explosion-proof fiber, 15 kg of binder, 0.1 kg of water-reducing agent, and 5 kg of water.

[0034] The pretreated corundum aggregate includes 18 kg of pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, 12 kg of pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and 8 kg of pretreated fused white corundum aggregate with a particle size of 3-1 mm. A silicon nitride suspension with a solid content of 15% is prepared. The 8-5 mm tabular corundum coarse aggregate, 5-3 mm tabular corundum medium aggregate, and 3-1 mm fused white corundum aggregate are vacuum impregnated in the silicon nitride particle suspension, dried at 100°C, and then heated at 800°C for 3 hours in a N2 atmosphere to obtain the 8-5 mm pretreated tabular corundum coarse aggregate, 5-3 mm pretreated tabular corundum medium aggregate, and 3-1 mm pretreated fused white corundum aggregate. After mixing, the pretreated corundum aggregate is obtained.

[0035] The silicon nitride particles include 16 kg of silicon nitride particles with a particle size of 5-3 mm and 8 kg of silicon nitride particles with a particle size of 3-1 mm.

[0036] NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm. The binder is calcium aluminate cement, the water-reducing agent is polycarboxylate water-reducing agent, and the length of the explosion-proof fiber is 15-25mm.

[0037] The casting method for yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of the mixed solution: Dissolve zirconium oxide and yttrium oxide in water to form a mixed solution, then add 2% (by mass) of polyethylene glycol 600 dispersant to the mixed solution. The molar ratio of zirconium oxide to yttrium oxide in the mixed solution is 1:1.5. The total molar concentration of zirconium oxide and yttrium oxide in the mixed solution is 2.5 mol / L.

[0038] S2, Prepare the precipitant solution: Dissolve the precipitant ammonium bicarbonate in water to form a precipitant solution; the molar amount of the precipitant is 4 times the total molar amount of zirconium oxide and yttrium oxide.

[0039] S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution for mixing. The mixing process is carried out at 60°C with high-speed stirring at a speed of 3000 r / min. The pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at 60°C for 1 hour at a speed of 3000 r / min.

[0040] S4, Aging: After the reaction is complete, aging is carried out by slow stirring for 2 hours at a stirring speed of 60 r / min.

[0041] S5, Post-processing: After aging, filter and wash until no chloride ions can be detected, then dry to obtain yttrium-stabilized zirconia micro powder as the initial product.

[0042] S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

[0043] NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 kg of Ni metal powder, 13 kg of Cr metal powder, 4 kg of Al metal powder, and 0.5 kg of Ti metal powder, respectively, and place them in anhydrous ethanol for ultrasonic cleaning for 10 min. After drying, mix them evenly and melt them in a vacuum melting furnace at 3000℃ for 60 min to obtain the initial alloy product.

[0044] S2, the initial alloy sample was placed in a muffle furnace and homogenized at 1100–1150℃ for 90 min. After cooling, it was hot-rolled three times at 850℃, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample was then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0045] The casting method of the wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 5 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 6 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 10 hours, and increase the temperature to 1450℃ at 30℃ / h and hold for 6 hours.

[0046] Example 3 The wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following raw materials: Pretreated corundum aggregate 37kg, silicon nitride particles 20kg, nano-silicon nitride powder 12kg, silicon powder 2kg, α-Al₂O₃ micro powder 6kg, yttrium-stabilized zirconium oxide micro powder 1kg, NiCr 13 Al4Ti 0.5 3 kg of alloy powder, 0.15 kg of explosion-proof fiber, 8 kg of binder, 0.2 kg of water-reducing agent, and 4 kg of water.

[0047] The pretreated corundum aggregate includes 15 kg of pretreated tabular corundum coarse aggregate (8-5 mm particle size), 10 kg of pretreated tabular corundum medium aggregate (5-3 mm particle size), and 12 kg of pretreated fused white corundum aggregate (3-1 mm particle size). A silicon nitride suspension with a solid content of 18% is prepared. The 8-5 mm tabular corundum coarse aggregate, 5-3 mm tabular corundum medium aggregate, and 3-1 mm fused white corundum aggregate are vacuum impregnated in the silicon nitride particle suspension, dried at 120°C, and then heated at 900°C for 3 hours in a N2 atmosphere to obtain the 8-5 mm pretreated tabular corundum coarse aggregate, 5-3 mm pretreated tabular corundum medium aggregate, and 3-1 mm pretreated fused white corundum aggregate. These are then mixed to obtain the pretreated corundum aggregate.

[0048] The silicon nitride particles include 10 kg of silicon nitride particles with a particle size of 5-3 mm and 10 kg of silicon nitride particles with a particle size of 3-1 mm.

[0049] NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm. The binder is calcium aluminate cement, the water-reducing agent is polycarboxylate water-reducing agent, and the length of the explosion-proof fiber is 15-25mm.

[0050] The casting method for yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of the mixed solution: Dissolve zirconium oxide and yttrium oxide in water to form a mixed solution, then add 2% (by mass) of polyethylene glycol 600 as a dispersant. The molar ratio of zirconium oxide to yttrium oxide in the mixed solution is 1:1. The total molar concentration of zirconium oxide and yttrium oxide in the mixed solution is 2 mol / L.

[0051] S2, Prepare the precipitant solution: Dissolve the precipitant ammonium bicarbonate in water to form a precipitant solution; the molar amount of the precipitant is 4 times the total molar amount of zirconium oxide and yttrium oxide.

[0052] S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution for mixing. The mixing process is carried out at 40°C with high-speed stirring at a speed of 3000 r / min. The pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at 40°C for 2 hours at a speed of 3000 r / min.

[0053] S4, Aging: After the reaction is complete, aging is carried out by slow stirring for 4 hours at a stirring speed of 60 r / min.

[0054] S5, Post-processing: After aging, filter and wash until no chloride ions can be detected, then dry to obtain yttrium-stabilized zirconia micro powder as the initial product.

[0055] S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

[0056] NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 kg of Ni metal powder, 13 kg of Cr metal powder, 4 kg of Al metal powder, and 0.5 kg of Ti metal powder, respectively, and ultrasonically clean them in anhydrous ethanol for 10 min. After drying, mix them evenly and melt them in a vacuum melting furnace at 2500℃ for 60 min to obtain the initial alloy product.

[0057] S2, the initial alloy sample was placed in a muffle furnace and homogenized at 1100–1150℃ for 90 min. After cooling, it was hot-rolled three times at 900℃, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample was then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0058] The casting method of the wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 4 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 7 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 10 hours, increase the temperature to 1450℃ at 30℃ / h and hold for 8 hours.

[0059] Example 4 The wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following raw materials: Pretreated corundum aggregate 34kg, silicon nitride particles 16kg, nano-silicon nitride powder 10kg, silicon powder 3kg, α-Al₂O₃ micro powder 8kg, yttrium-stabilized zirconium oxide micro powder 2kg, NiCr 13 Al4Ti 0.5 2 kg of alloy powder, 0.1 kg of explosion-proof fiber, 15 kg of binder, 0.1 kg of water-reducing agent, and 3 kg of water.

[0060] The pretreated corundum aggregate includes 12 kg of pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, 12 kg of pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and 10 kg of pretreated fused white corundum aggregate with a particle size of 3-1 mm. A silicon nitride suspension with a solid content of 18% is prepared. The 8-5 mm tabular corundum coarse aggregate, the 5-3 mm tabular corundum medium aggregate, and the 3-1 mm fused white corundum aggregate are vacuum impregnated in the silicon nitride particle suspension, dried at 100°C, and then heated at 900°C for 3 hours in a N2 atmosphere to obtain the 8-5 mm pretreated tabular corundum coarse aggregate, the 5-3 mm pretreated tabular corundum medium aggregate, and the 3-1 mm pretreated fused white corundum aggregate. After mixing, the pretreated corundum aggregate is obtained.

[0061] The silicon nitride particles include 10 kg of silicon nitride particles with a particle size of 5-3 mm and 6 kg of silicon nitride particles with a particle size of 3-1 mm.

[0062] NiCr 13 Al4Ti0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm. The binder is calcium aluminate cement, the water-reducing agent is polycarboxylate water-reducing agent, and the length of the explosion-proof fiber is 15-25mm.

[0063] The casting method for yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of the mixed solution: Dissolve zirconium oxide and yttrium oxide in water to form a mixed solution, then add 2% (by mass) of polyethylene glycol 600 as a dispersant. The molar ratio of zirconium oxide to yttrium oxide in the mixed solution is 1:1. The total molar concentration of zirconium oxide and yttrium oxide in the mixed solution is 2 mol / L.

[0064] S2, Prepare the precipitant solution: Dissolve the precipitant ammonium bicarbonate in water to form a precipitant solution; the molar amount of the precipitant is 4 times the total molar amount of zirconium oxide and yttrium oxide.

[0065] S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution for mixing. The mixing process is carried out at 40°C with high-speed stirring at a speed of 3000 r / min. The pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at 40°C for 2 hours at a speed of 3000 r / min.

[0066] S4, Aging: After the reaction is complete, aging is carried out by slow stirring for 4 hours at a stirring speed of 60 r / min.

[0067] S5, Post-processing: After aging, filter and wash until no chloride ions can be detected, then dry to obtain yttrium-stabilized zirconia micro powder as the initial product.

[0068] S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

[0069] NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 kg of Ni metal powder, 13 kg of Cr metal powder, 4 kg of Al metal powder, and 0.5 kg of Ti metal powder, respectively, and ultrasonically clean them in anhydrous ethanol for 10 min. After drying, mix them evenly and melt them in a vacuum melting furnace at 2500℃ for 60 min to obtain the initial alloy product.

[0070] S2, the initial alloy sample was placed in a muffle furnace and homogenized at 1100–1150℃ for 90 min. After cooling, it was hot-rolled three times at 900℃, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample was then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0071] The casting method of the wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 4 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 8 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 8 hours, increase the temperature to 1450℃ at 30℃ / h and hold for 10 hours.

[0072] Example 5 The wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following raw materials: Pretreated corundum aggregate 30-45 kg, silicon nitride particles 16-26 kg, nano-silicon nitride powder 6 kg, silicon powder 2 kg, α-Al₂O₃ micro powder 6 kg, yttrium-stabilized zirconium oxide micro powder 1 kg, NiCr 13 Al4Ti 0.5 3 kg of alloy powder, 0.15 kg of explosion-proof fiber, 12 kg of binder, 0.2 kg of water-reducing agent, and 4 kg of water.

[0073] The pretreated corundum aggregate includes 15 kg of pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, 15 kg of pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and 8 kg of pretreated fused white corundum aggregate with a particle size of 3-1 mm. A silicon nitride suspension with a solid content of 15% is prepared. The 8-5 mm tabular corundum coarse aggregate, the 5-3 mm tabular corundum medium aggregate, and the 3-1 mm fused white corundum aggregate are vacuum impregnated in the silicon nitride particle suspension, dried at 120°C, and then heated at 850°C for 3 hours in a N2 atmosphere to obtain the 8-5 mm pretreated tabular corundum coarse aggregate, the 5-3 mm pretreated tabular corundum medium aggregate, and the 3-1 mm pretreated fused white corundum aggregate. After mixing, the pretreated corundum aggregate is obtained.

[0074] The silicon nitride particles include 10 kg of silicon nitride particles with a particle size of 5-3 mm and 8 kg of silicon nitride particles with a particle size of 3-1 mm.

[0075] NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm. The binder is calcium aluminate cement, the water-reducing agent is polycarboxylate water-reducing agent, and the length of the explosion-proof fiber is 15-25mm.

[0076] Yttrium-stabilized zirconia micro powder was purchased from Jiaozuo Zhongcheng New Materials Co., Ltd.

[0077] NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 kg of Ni metal powder, 13 kg of Cr metal powder, 4 kg of Al metal powder, and 0.5 kg of Ti metal powder, respectively, and ultrasonically clean them in anhydrous ethanol for 10 min. After drying, mix them evenly and melt them in a vacuum melting furnace at 2500℃ for 60 min to obtain the initial alloy product.

[0078] S2, the initial alloy sample was placed in a muffle furnace and homogenized at 1100–1150℃ for 90 min. After cooling, it was hot-rolled three times at 900℃, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample was then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

[0079] The casting method of the wear-resistant castable for the alumina suspension calcining furnace in this embodiment includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 5 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 6 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 8 hours, and increase the temperature to 1450℃ at 30℃ / h and hold for 8 hours.

[0080] Comparative Example 1 The wear-resistant castable for the alumina suspension calcining furnace in this comparative example contains roughly the same raw materials as in Example 1, except that NiCr is not added. 13 Al4Ti 0.5 The alloy powder, α-Al2O3 micro powder, is added at a rate of 10 kg.

[0081] Comparative Example 2 The wear-resistant castable for the alumina suspension calcining furnace in this comparative example contains roughly the same raw materials as in Example 1, except that yttrium-stabilized zirconia micro powder is not added, and the amount of α-Al2O3 micro powder added is 10 kg.

[0082] Comparative Example 3 The wear-resistant castable for the alumina suspension calcining furnace in this comparative example contains roughly the same raw materials as in Example 1. The difference is that no nano-silicon nitride powder is added, and the amount of silicon nitride particles with a particle size of 5-3 mm is 18 kg and the amount of silicon nitride particles with a particle size of 3-1 mm is 11 kg.

[0083] Comparative Example 4 The wear-resistant castable for the alumina suspension calcination furnace in this comparative example contains roughly the same raw materials as in Example 1, except that it includes the following raw materials: 37 kg of corundum aggregate, 21 kg of silicon nitride particles, 8 kg of nano-silicon nitride powder, 2 kg of silicon powder, 8 kg of α-Al₂O₃ micro powder, 2 kg of yttrium-stabilized zirconium oxide micro powder, and NiCr. 13 Al4Ti 0.5 The mixture contains 2 kg of alloy powder, 0.1 kg of explosion-proof fiber, 4 kg of binder, 0.2 kg of water-reducing agent, and 3 kg of water. The corundum aggregate is untreated, consisting of 15 kg of tabular coarse corundum aggregate with a particle size of 8-5 mm, 15 kg of tabular medium corundum aggregate with a particle size of 5-3 mm, and 8 kg of fused white corundum aggregate with a particle size of 3-1 mm.

[0084] Test case 1. Test the bulk density and porosity according to GB / T 4513.6-2017; 2. According to GB / T 30873-2014, the thermal shock resistance performance was tested: the sample was placed in a resistance furnace and kept at 1100 ℃ for 20 min, then removed and placed in room temperature water for 5 min, placed in the air for 5 min, and then placed in the resistance furnace for 20 min. This process was repeated 15 times. 3. Abrasion resistance was tested according to GB / T 18301-2012; 4. Alkali resistance was tested according to GB / T 14983-2008; 5. Test the compressive strength at room temperature according to GB / T 5072-2023; 6. Test the permanent linear change rate of heating according to GB / T 5988-2022.

[0085] The test results are shown in Table 1.

[0086] Table 1 Performance Tests of Wear-Resistant Castables for Alumina Suspension Calcining Furnaces in Examples 1-3 and Comparative Examples 1-4

[0087] As can be seen from Table 1, the wear-resistant castable for the alumina suspension calcining furnace of the present invention possesses thermal shock resistance and wear resistance. NiCr 13 Al4Ti 0.5 Alloy powder and yttrium-stabilized zirconia micro powder improve wear resistance. Corundum aggregate pretreated with silicon nitride reduces porosity, increases bulk density, and also exhibits good alkali resistance and wear resistance.

[0088] Figure 1 The images show the wear resistance of the alumina suspension calcining furnace wear-resistant castables from Examples 1-3 and Comparative Examples 1-4 after wear resistance testing. It can be seen that the alumina suspension calcining furnace wear-resistant castables from Examples 1-3 exhibit better wear resistance and less wear. The alumina suspension calcining furnace wear-resistant castables from Comparative Examples 1-4 show more severe wear.

[0089] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the content of the present invention's specification shall also be included within the scope of protection of the present invention.

Claims

1. A wear-resistant castable for an alumina suspension calcining furnace, characterized in that, The following raw materials are included in parts by weight: Pretreated corundum aggregate 30-45 parts, silicon nitride particles 16-26 parts, nano-silicon nitride powder 6-12 parts, silicon powder 2-3 parts, α-Al₂O₃ micro powder 6-8 parts, yttrium-stabilized zirconium oxide micro powder 1-3 parts, NiCr 13 Al4Ti 0.5 The alloy powder consists of 1-3 parts, explosion-proof fiber of 0.1-0.15 parts, binder of 8-15 parts, and water-reducing agent of 0.1-0.2 parts.

2. The wear-resistant castable for alumina suspension calcining furnace according to claim 1, characterized in that, The casting method for the yttrium-stabilized zirconia micro powder includes the following steps: S1, Preparation of mixed solution: Dissolve zirconium source and yttrium source in water to form a mixed solution, and then add 2-3% of dispersant by mass of the mixed solution; S2, Prepare the precipitant solution: Dissolve the precipitant in water to form a precipitant solution; S3, Precipitation reaction: The mixed solution is slowly added to the precipitant solution and mixed. During the mixing process, the mixture is stirred at high speed at 40-60℃, and the pH is controlled between 9 and 10. After the mixed solution is added, the mixture is stirred at high speed at 40-60℃ for 0.5-2 hours. S4, Aging: After the reaction is complete, aging is carried out with slow stirring for 1 to 4 hours; S5, Post-processing: After aging, filter and wash until chloride ions are undetectable, then dry to obtain yttrium-stabilized zirconia micro powder. S6, Calcination: The initial yttrium-stabilized zirconia micro powder is calcined. The heating program is as follows: increase the temperature to 200℃ at 2℃ / min, increase the temperature to 400℃ at 1℃ / min, increase the temperature to 600℃ at 2℃ / min, increase the temperature to 1000℃ at 5℃ / min, and hold at 1000℃ for 2 hours.

3. The wear-resistant castable for alumina suspension calcining furnace according to claim 2, characterized in that, The yttrium salt is yttrium oxide, the zirconium source is zirconium oxide, the molar ratio of zirconium source to yttrium source in the mixed solution is 1:1 to 1:1.5, and the total molar concentration of zirconium source and yttrium source in the mixed solution is 2 to 3 mol / L.

4. The wear-resistant castable for alumina suspension calcining furnace according to claim 2, characterized in that, The dispersant is polyethylene glycol 600, and the precipitant is ammonium bicarbonate. The molar amount of the precipitant is 3.6 to 4 times the total molar amount of the zirconium source and the yttrium source.

5. The wear-resistant castable for an alumina suspension calcining furnace according to claim 1, characterized in that, The NiCr 13 Al4Ti 0.5 The alloy powder preparation method includes the following steps: S1. Take 1 part by mass of Ni metal powder, 13 parts by mass of Cr metal powder, 4 parts by mass of Al metal powder, and 0.5 parts by mass of Ti metal powder, respectively place them in anhydrous ethanol and ultrasonically clean for 10-20 minutes. After drying, mix them evenly and melt them in a vacuum induction melting furnace at 2500-3000℃ for 30-60 minutes to obtain the initial alloy product. S2, the initial alloy sample is placed in a muffle furnace and homogenized at 1100–1150℃ for 90–120 min. After cooling, it is hot-rolled at 850–900℃ for 3–5 passes, followed by annealing and gradual cooling to room temperature to obtain an alloy sample. The alloy sample is then crushed and ball-milled into NiCr. 13 Al4Ti 0.5 Alloy powder.

6. The wear-resistant castable for an alumina suspension calcining furnace according to claim 1, characterized in that, The pretreated corundum aggregate includes 12-18 parts by weight of pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, 10-15 parts by weight of pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and 8-12 parts by weight of pretreated fused white corundum aggregate with a particle size of 3-1 mm; a silicon nitride suspension with a solid content of 15-18% is prepared, and the pretreated tabular corundum coarse aggregate with a particle size of 8-5 mm, the pretreated tabular corundum medium aggregate with a particle size of 5-3 mm, and the pretreated fused white corundum aggregate with a particle size of 3-1 mm are then added. Electrofused white corundum aggregates with a particle size of 3–1 mm were vacuum impregnated in a silicon nitride particle suspension, dried at 100–120°C, and then heated at 800–900°C for 2–3 hours in an N2 atmosphere to obtain pretreated tabular corundum coarse aggregates with a particle size of 8–5 mm, pretreated tabular corundum medium aggregates with a particle size of 5–3 mm, and pretreated electrofused white corundum aggregates with a particle size of 3–1 mm. After mixing, pretreated corundum aggregates were obtained.

7. The wear-resistant castable for an alumina suspension calcining furnace according to claim 1, characterized in that, The silicon nitride particles comprise 10-16 parts by weight of silicon nitride particles with a particle size of 5-3 mm and 6-10 parts by weight of silicon nitride particles with a particle size of 3-1 mm.

8. The wear-resistant castable for an alumina suspension calcining furnace according to claim 1, characterized in that, The NiCr 13 Al4Ti 0.5 The particle size of the alloy powder is ≤5μm, and the particle size of the yttrium-stabilized zirconia micro powder is ≤5μm.

9. The wear-resistant castable for an alumina suspension calcining furnace according to claim 1, characterized in that, The binder is calcium aluminate cement, and the length of the explosion-proof fiber is 15-25 mm.

10. The casting method of the wear-resistant castable for alumina suspension calcining furnace as described in claim 1, characterized in that, Includes the following steps: S1, mix the pretreated corundum aggregate, silicon nitride particles, nano silicon nitride powder and silicon powder in the formula evenly to obtain aggregate; S2, α-Al2O3 micro powder, yttrium-stabilized zirconium oxide micro powder, NiCr 13 Al4Ti 0.5 Alloy powder and explosion-proof fiber are mixed evenly to obtain a matrix; S3: Prepare a water-reducing agent aqueous solution by mixing the water-reducing agent with water, add the matrix to the aggregate and mix evenly, add the binder and the water-reducing agent aqueous solution and stir evenly, let stand for 2-3 minutes and then pour, vibrate during the pouring process, and cure after pouring. S4: After curing, sintering is carried out. The heating program is as follows: cure at 110℃ for 24 hours, then increase the temperature to 400℃ at 10℃ / h and hold for 6 hours, increase the temperature to 800℃ at 10℃ / h and hold for 4-5 hours, increase the temperature to 1100℃ at 30℃ / h and hold for 6-8 hours, increase the temperature to 1300℃ at 40℃ / h and hold for 8-10 hours, and increase the temperature to 1450℃ at 30℃ / h and hold for 6-10 hours.

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