Composite long-service-life ladle nozzle pocket block for steelmaking refining and preparation method of composite long-service-life ladle nozzle pocket block

Abstract

The invention relates to the technical field of steelmaking refining refractory materials, in particular to a composite long-service-life ladle nozzle pocket block for steelmaking refining and a preparation method of the composite long-service-life ladle nozzle pocket block. The ladle nozzle pocket block comprises a pocket block inner core, the inner core is cylindrical, a steel flowing hole is formed in the center of the inner core from top to bottom, the inner core comprises an upper inner core and a lower inner core which are aligned and matched, the upper inner core and the lower inner core are formed in a mechanical pressing mode, a pouring piece is arranged on the outer side of the inner core, the pouring piece is flush with the end face of the top of the inner core, and the upper inner core and the lower inner core are arranged in the pocket block inner core. The bottom of the pouring part extends towards the lower portion of the inner core, a mounting hole is formed in the center of the bottom of the pouring part, the diameter of the mounting hole is larger than that of the steel flowing hole, and the mounting hole and the steel flowing hole are coaxial. The service life of the ladle nozzle seating brick can be prolonged to 90 times or above, the use cost and the labor cost of ladle masonry refractory materials are reduced, and meanwhile the safety performance of online use of a ladle is improved.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials for steelmaking and refining, in particular to a composite high-life ladle nozzle seat brick for steelmaking and refining and a preparation method thereof. Background Art

[0002] The ladle tank is a device used to carry high-temperature molten steel in the steelmaking and continuous casting production processes. Its main function is to store and transport molten steel. During the continuous casting process, the molten steel flows out through the inner hole channel of the ladle water inlet brick, enters the tundish, and finally reaches the crystallizer.

[0003] During the pouring process, more than 200 tons of molten steel at a pouring temperature of 1540℃ flowed into the tundish through the inner hole channel of the ladle nozzle seat brick. The normal pouring time of each furnace of molten steel is about 30 minutes. However, in the process of direct contact with high-temperature molten steel, the inner hole of the ladle nozzle seat brick is affected by mechanical scouring and erosion by slag at the end of pouring, resulting in the gradual expansion of its inner hole diameter and the gradual shortening of its height. This situation seriously limits the service life of the ladle nozzle seat brick, and also poses a great safety risk.

[0004] Therefore, improving the resistance of ladle nozzle seat bricks to scouring and erosion by high-temperature molten steel in order to extend their service life from 70 times to more than 100 times has become a technical problem that needs to be urgently solved by technicians in the field of steel smelting. Summary of the invention

[0005] The purpose of the present invention is to provide a composite high-life ladle nozzle seat brick for steelmaking and refining, which can solve the technical problems of the ladle nozzle seat brick under the scouring and erosion of high-temperature molten steel, as well as the high porosity, low bulk density, and erosion resistance.

[0006] The present invention provides a composite high-life ladle nozzle seat brick for steelmaking and refining, comprising a seat brick inner core, the inner core is cylindrical, a steel flow hole is arranged at the center of the inner core from top to bottom, the inner core comprises an upper inner core and a lower inner core which are aligned and matched, the upper inner core and the lower inner core are formed by machine pressing, a casting is arranged on the outer side of the inner core, the casting is flush with the top end surface of the inner core, the bottom of the casting extends below the inner core, a mounting hole is arranged at the center of the bottom of the casting, the diameter of the mounting hole is larger than the diameter of the steel flow hole, and the mounting hole is coaxial with the steel flow hole.

[0007] Preferably, the height of the upper inner core is 175-190 mm, a boss is provided at the bottom center of the upper inner core, the height of the lower inner core is 200-210 mm, a groove is provided at the top center of the lower inner core, and the groove is aligned with the boss.

[0008] Preferably, the inner core comprises the following raw material components in weight percentage: 96% magnesia 7-14%, 97% magnesia 60-75%, 97% graphite 7-18%, metal aluminum silicon powder 4-7%, and phenolic resin 1-4%.

[0009] Preferably, the particle size of the 96% magnesia is 9-24 mm; the particle size of the 97% magnesia is 3-5 mm, 1-3 mm, 0-1 mm and 200 mesh fine powder, and the weight percentage of each particle size in the 97% magnesia is 20-35%, 20-25%, 15-25% and 25-35% respectively.

[0010] 96% magnesia and 97% magnesia cooperate with each other to form a relatively compact particle stacking structure, which is sufficient to serve as the skeleton material of the inner core and enhance the overall strength of the inner core. The fine-grained 97% magnesia (0-1mm and 200 mesh fine powder) can fill in the gaps between the coarse particles, reduce the porosity of the inner core, and increase the volume density, thereby reducing the channels for molten steel penetration and erosion, and enhancing the corrosion resistance of the inner core.

[0011] Preferably, the casting adopts high-purity chrome-magnesium corundum casting material, including the following raw material components in mass percentage: 20-30% of fused white corundum with a particle size of 10mm≦<15mm, 10-12% of fused white corundum with a particle size of 5mm≦<10mm, 8-11% of fused white corundum with a particle size of 3mm≦<5mm, 9-11% of fused white corundum with a particle size of 1mm≦<3mm, 8-15% of fused white corundum with a particle size of 0.088mm≦<1mm, and plate-shaped Corundum fine powder 10-13%, plate-shaped corundum powder with particle size <0.044mm 4-7%, fused magnesia fine powder with particle size 0.088mm≦<0.5mm 0.8-3.5%, fused magnesia powder with particle size ≦0.044mm 1.0-3.0%, fused Cr2O3 powder 4.0-6.0%, fused spinel powder with particle size <0.044mm 2.0-4.0%, pure calcium aluminate cement 3-5%, sodium hexametaphosphate 0.1-0.3%, and heat-resistant steel fiber 0.03-0.08%.

[0012] The present invention also provides a method for preparing a composite high-life ladle nozzle seat brick for steelmaking and refining, comprising the following steps:

[0013] S1. The upper inner core and the lower inner core are prepared by machine compression molding, and the upper inner core and the lower inner core are aligned and assembled to obtain an inner core;

[0014] S2. The assembled inner core is placed in a block mold, and then a high-purity chromium-magnesium-corundum castable is poured between the inner core and the block mold to obtain a green embryo of a ladle nozzle block;

[0015] S3. The green bricks of the ladle nozzle seat are baked and cooled to obtain composite high-life ladle nozzle seat bricks for steelmaking and refining.

[0016] Preferably, the specific steps of step S1 include:

[0017] a. Weigh the raw materials according to the formula, put 96% magnesia and 97% magnesia into the mixer, then put the phenolic resin, premix for 3-5min, put 97% graphite and metal aluminum silicon powder into the mixer, mix for 15-20min to obtain a mixture;

[0018] b. The mixed material is added to a mold for compression molding to obtain an upper core embryo and a lower core embryo;

[0019] c. Drying the upper inner core embryo and the lower inner core embryo in sections to obtain the upper inner core and the lower inner core, and aligning and assembling the upper inner core and the lower inner core to obtain the inner core.

[0020] Preferably, the specific steps of segmented drying in step c include: baking from room temperature at a heating rate of 35-40°C / h, when the temperature reaches 200°C, continuing to keep warm and bake for 8-10 hours, and then baking at a cooling rate of 11°C / h for 12 hours.

[0021] Preferably, the specific steps of step S2 include:

[0022] A. After evenly brushing oil on the inner wall of the block mold, place it on a vibration table and put the inner core into the block mold;

[0023] B. After the high-purity chrome-magnesium-corundum castable is prepared according to the components, dry-mix for 4-9 minutes, and after mixing evenly, add 5-6% of the total weight of water, wet-mix for 5-10 minutes, and mix evenly to obtain the mud;

[0024] C. Add the mud between the inner core and the base brick mold, vibrate while adding the mud until the mud is flush with the upper edge of the base brick mold, and continue vibrating until the surface is dense and slurry is formed;

[0025] D. After curing for 3-4 days at a temperature of 15-29°C and a humidity greater than 90%, demoulding is performed to obtain the green bricks of the ladle nozzle seat.

[0026] Preferably, the specific step of S3 includes: heating the green brick of the ladle nozzle seat from room temperature to 140-160°C at a heating rate of 10°C / h, and keeping it warm for 12-24h; then heating from 140-160°C to 240-260°C at a heating rate of 10°C / h, and keeping it warm for 10-12h; then heating from 240-260°C to 600-650°C at a heating rate of 15°C / h, keeping it warm for 10-12h, stopping the fire and cooling naturally for 12-24h to obtain a composite high-life ladle nozzle seat brick for steelmaking and refining.

[0027] Beneficial effects:

[0028] The inner core of the present invention is formed by machine pressing, and the upper inner core and the lower inner core are tightly combined (the installation concentricity is maintained within the range of 1mm), which improves the overall strength and stability of the inner core. The outer part around the inner core is cast and formed by corundum castable material, which improves the resistance of the ladle nozzle seat brick to high-temperature molten steel scouring and erosion, thereby improving the service life of the ladle nozzle seat brick, and can increase the service life of the ladle nozzle seat brick to more than 90 times, reducing the use cost and labor cost of the ladle masonry refractory materials, and at the same time improving the safety performance of the ladle in online use.

[0029] The pouring piece on the outer side of the inner core of the present invention is flush with the top end surface of the inner core and extends at the bottom, and is provided with a mounting hole coaxial with the steel flow hole, which can further protect the inner core and reduce erosion while ensuring smooth outflow of molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of the inner core split structure of Example 1 of the present invention;

[0032] Figure 2 It is a schematic cross-sectional diagram of the overall structure of Example 1 of the present invention.

[0033] Description of reference numerals:

[0034] 1-upper inner core, 2-boss, 3-steel flow hole, 4-lower inner core, 5-groove, 6-casting, 7-mounting hole. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Example 1

[0039] like Figure 1-2As shown, a composite high-life ladle nozzle seat brick for steelmaking and refining includes a seat brick inner core, the inner core is cylindrical, a steel flow hole 3 is arranged at the center of the inner core from top to bottom, the top diameter of the steel flow hole 3 is larger than the bottom diameter, the inner core includes an upper inner core 1 and a lower inner core 4 that are aligned and fit together, the upper inner core 1 and the lower inner core 4 are machine pressed, and the outer diameters of both are 300 mm, the upper inner core 1 is 190 mm high, a 15 mm high boss 2 is arranged at the bottom center of the upper inner core 1, the outer diameter of the boss 2 is 270 mm, the upper inner diameter of the steel flow hole 3 of the upper inner core 1 is 110 mm, and the lower inner diameter is 108 mm; the lower inner core 4 is 205 mm high, a 15 mm high groove 5 is arranged at the top center of the lower inner core 4, and the groove 5 is aligned and fits with the boss 2. A lower inner core 4 is provided on the outside of the inner core. The lower inner core 4 is flush with the top end face of the inner core. The bottom of the lower inner core 4 extends downwardly to the inner core. A mounting hole 7 is provided at the center of the bottom of the lower inner core 4. The mounting hole 7 includes an upper conical channel and a lower cylindrical channel. The diameter of the mounting hole 7 is larger than the diameter of the flow steel hole 3. The mounting hole 7 is coaxial with the flow steel hole 3.

[0040] The inner core includes the following raw material components in weight percentage: 12% of 96% magnesia, 65% of 97% magnesia, 15% of 97% graphite, 5% of metal aluminum silicon powder, and 3% of phenolic resin. The particle size of 96% magnesia is 15-20mm; the particle size of 97% magnesia is 3-5mm, 1-3mm, 0-1mm and 200 mesh fine powder, and the weight percentage of each particle size in 97% magnesia is 20%, 25%, 25% and 30% respectively.

[0041] The lower inner core 4 is made of high-purity chrome-magnesium corundum castable, including the following raw material components by mass percentage: 25% of fused white corundum with a particle size of 10mm≦<15mm, 12% of fused white corundum with a particle size of 5mm≦<10mm, 10% of fused white corundum with a particle size of 3mm≦<5mm, 9% of fused white corundum with a particle size of 1mm≦<3mm, 12% of fused white corundum with a particle size of 0.088mm≦<1mm, and 0.044mm≦< 0.088mm plate-shaped corundum fine powder 11%, plate-shaped corundum micropowder with particle size <0.044mm 5%, fused magnesia fine powder with particle size 0.088mm≦<0.5mm 2%, fused magnesia micropowder with particle size ≦0.044mm 2%, fused Cr2O3 micropowder 5%, fused spinel micropowder with particle size <0.044mm 3%, pure calcium aluminate cement 3.7%, sodium hexametaphosphate 0.25%, and heat-resistant steel fiber 0.05%.

[0042] A method for preparing a composite high-life ladle nozzle seat brick for steelmaking and refining, comprising the following steps:

[0043] S1. Preparation of upper inner core 1 and lower inner core 4:

[0044] a. Weigh the raw materials according to the formula, put 96% magnesia and 97% magnesia as aggregate into the mixer, then put phenolic resin, premix for 5 minutes, put 97% graphite and metal aluminum silicon powder into the mixer, mix for 15 minutes to obtain a mixture;

[0045] b. The mixed mixture was added to the mold for compression molding, first struck 4 times with a force of 2500kN, and then struck 7 times with a force of 6000kN, so that the inner core size reached the standard, to obtain an upper core 1 embryo and a lower core 4 embryo;

[0046] c. Dry the raw embryos of the upper inner core 1 and the lower inner core 4 in sections, bake them from room temperature at a heating rate of 37°C / h, and when the temperature reaches 200°C, continue to keep warm and bake for 9 hours, and then bake them at a cooling rate of 11°C / h for 12 hours to obtain the upper inner core 1 and the lower inner core 4, and assemble the upper inner core 1 and the lower inner core 4 to obtain the inner core.

[0047] S2. Preparation of green bricks for ladle nozzle seat:

[0048] A. After evenly brushing oil on the inner wall of the block mold, place it on the vibration table and put the assembled inner core into the block mold;

[0049] B. After the high-purity chrome-magnesium corundum castable is prepared according to the components, dry-mix for 5 minutes, and after mixing evenly, add 5% of the total weight of water, wet-mix for 8 minutes, and mix evenly to obtain the mud;

[0050] C. Add the mud between the inner core and the base brick mold, vibrate while adding the mud until the mud is level with the upper edge of the base brick mold, and continue vibrating until the surface is dense and slurry is formed;

[0051] D. After curing for 3 days at a temperature of 25-29°C and a humidity greater than 90%, demoulding is performed to obtain the green bricks of the ladle nozzle seat.

[0052] S3. The green bricks of the ladle nozzle seat are heated from room temperature to 150°C at a heating rate of 10°C / h, and kept warm for 18 hours; then the green bricks are heated from 150°C to 250°C at a heating rate of 10°C / h, and kept warm for 12 hours; then the green bricks are heated from 250°C to 600°C at a heating rate of 15°C / h, and kept warm for 12 hours. Then the green bricks are cooled naturally for 12 hours to obtain composite high-life ladle nozzle seat bricks for steelmaking and refining.

[0053] The composite high-life ladle nozzle seat brick for steelmaking and refining prepared in Example 1 has a service life of 95-98 times.

[0054] Example 2

[0055] A composite high-life ladle nozzle seat brick for steelmaking and refining, comprising a seat brick inner core, the inner core is cylindrical, a steel flow hole 3 is arranged from top to bottom in the center of the inner core, the top diameter of the steel flow hole 3 is larger than the bottom diameter, the inner core comprises an upper inner core 1 and a lower inner core 4 which are aligned and matched, the upper inner core 1 and the lower inner core 4 are formed by machine pressing, both of which have an outer diameter of 300 mm, the upper inner core 1 is 175 mm high, a 15 mm high boss 2 is arranged at the bottom center of the upper inner core 1, the outer diameter of the boss 2 is 270 mm, the upper inner diameter of the steel flow hole 3 of the upper inner core 1 is 110 mm, and the lower inner diameter is 108 mm; the lower inner core 4 is 200 mm high, a 15 mm high groove 5 is arranged at the top center of the lower inner core 4, and the groove 5 is aligned and matched with the boss 2. A lower inner core 4 is arranged outside the inner core, and the lower inner core 4 is flush with the top end surface of the inner core. The bottom of the lower inner core 4 extends downwardly to the bottom of the inner core. A mounting hole 7 is arranged at the center of the bottom of the lower inner core 4. The mounting hole 7 includes an upper truncated cone channel and a lower cylindrical channel. The diameter of the mounting hole 7 is larger than the diameter of the steel flow hole 3, and the mounting hole 7 is coaxial with the steel flow hole 3. The above structure is Figure 1-2 Same, only different size.

[0056] The inner core comprises the following raw material components in weight percentage: 7% of 96% magnesia, 75% of 97% magnesia, 7% of 97% graphite, 7% of metal aluminum silicon powder, and 4% of phenolic resin. The particle size of 96% magnesia is 9-20mm; the particle size of 97% magnesia is 3-5mm, 1-3mm, 0-1mm and 200 mesh fine powder, and the weight percentage of each particle size in 97% magnesia is 30%, 20%, 15% and 35% respectively.

[0057] The lower inner core 4 is made of high-purity chromium-magnesium corundum castable, including the following raw material components in mass percentage: 20% of fused white corundum with a particle size of 10mm≦<15mm, 10% of fused white corundum with a particle size of 5mm≦<10mm, 11% of fused white corundum with a particle size of 3mm≦<5mm, 10.17% of fused white corundum with a particle size of 1mm≦<3mm, 15% of fused white corundum with a particle size of 0.088mm≦<1mm, and 0.044mm≦ 13% of plate-like corundum fine powder with particle size <0.088mm, 7% of plate-like corundum micropowder with particle size <0.044mm, 3.5% of fused magnesia fine powder with particle size 0.088mm≦<0.5mm, 1% of fused magnesia micropowder with particle size ≦0.044mm, 4% of fused Cr2O3 micropowder, 2% of fused spinel micropowder with particle size <0.044mm, 3% of pure calcium aluminate cement, 0.3% of sodium hexametaphosphate, and 0.03% of heat-resistant steel fiber.

[0058] A method for preparing a composite high-life ladle nozzle seat brick for steelmaking and refining, comprising the following steps:

[0059] S1. Preparation of upper inner core 1 and lower inner core 4:

[0060] a. Weigh the raw materials according to the formula, put 96% magnesia and 97% magnesia as aggregate into the mixer, then put the phenolic resin, premix for 3 minutes, put 97% graphite and metal aluminum silicon powder into the mixer, mix for 20 minutes to obtain a mixture;

[0061] b. The mixed mixture was added to the mold for compression molding, first with a force of 3000kN 3-4 times, and then with a force of 6500kN 5 times, so that the inner core size standard, to obtain an upper core 1 embryo and the lower core 4 embryo;

[0062] c. Dry the raw embryos of the upper inner core 1 and the lower inner core 4 in sections, bake them from room temperature at a heating rate of 35°C / h, and when the temperature reaches 200°C, continue to keep warm and bake for 8 hours, and then bake them at a cooling rate of 11°C / h for 12 hours to obtain the upper inner core 1 and the lower inner core 4, assemble the upper inner core 1 and the lower inner core 4 in position to obtain the inner core, and during installation, the concentricity of the upper inner core 1 and the lower inner core 4 is within 1mm.

[0063] S2. Preparation of green bricks for ladle nozzle seat:

[0064] A. After evenly brushing oil on the inner wall of the block mold, place it on the vibration table and put the inner core into the block mold;

[0065] B. After the high-purity chrome-magnesium-corundum castable is prepared according to the components, dry-mix for 4 minutes, and after mixing evenly, add 6% of the total weight of the material into water, wet-mix for 5 minutes, and mix evenly to obtain the mud;

[0066] C. Add the mud between the inner core and the base brick mold, vibrate while adding the mud until the mud is level with the upper edge of the base brick mold, and continue vibrating until the surface is dense and slurry is formed;

[0067] D. After curing for 4 days at a temperature of 15-25°C and a humidity greater than 90%, demoulding is performed to obtain the green bricks of the ladle nozzle seat.

[0068] S3. The green bricks of the ladle nozzle seat are heated from room temperature to 140°C at a heating rate of 10°C / h, and kept warm for 24 hours; then the green bricks are heated from 140°C to 260°C at a heating rate of 10°C / h, and kept warm for 10 hours; then the green bricks are heated from 260°C to 650°C at a heating rate of 15°C / h, and kept warm for 10 hours. The green bricks are then cooled naturally for 24 hours to obtain composite high-life ladle nozzle seat bricks for steelmaking and refining.

[0069] The composite high-life ladle nozzle seat brick for steelmaking and refining prepared in Example 2 has a service life of 90-92 times.

[0070] Example 3

[0071] A composite high-life ladle nozzle seat brick for steelmaking and refining, comprising a seat brick inner core, the inner core is cylindrical, a steel flow hole 3 is arranged from top to bottom in the center of the inner core, the top diameter of the steel flow hole 3 is larger than the bottom diameter, the inner core comprises an upper inner core 1 and a lower inner core 4 which are aligned and matched, the upper inner core 1 and the lower inner core 4 are formed by machine pressing, both of which have an outer diameter of 300 mm, the upper inner core 1 is 180 mm high, a 15 mm high boss 2 is arranged at the bottom center of the upper inner core 1, the outer diameter of the boss 2 is 270 mm, the upper inner diameter of the steel flow hole 3 of the upper inner core 1 is 110 mm, and the lower inner diameter is 108 mm; the lower inner core 4 is 190 mm high, a 15 mm high groove 5 is arranged at the top center of the lower inner core 4, and the groove 5 is aligned and matched with the boss 2. A lower inner core 4 is arranged outside the inner core, and the lower inner core 4 is flush with the top end surface of the inner core. The bottom of the lower inner core 4 extends downwardly to the bottom of the inner core. A mounting hole 7 is arranged at the center of the bottom of the lower inner core 4. The mounting hole 7 includes an upper truncated cone channel and a lower cylindrical channel. The diameter of the mounting hole 7 is larger than the diameter of the steel flow hole 3, and the mounting hole 7 is coaxial with the steel flow hole 3. The above structure is Figure 1-2 Same, only different size.

[0072] The inner core comprises the following raw material components in weight percentage: 14% of 96% magnesia, 64% of 97% magnesia, 18% of 97% graphite, 4% of metal aluminum silicon powder, and 1% of phenolic resin. The particle size of 96% magnesia is 9-24mm; the particle size of 97% magnesia is 3-5mm, 1-3mm, 0-1mm and 200 mesh fine powder, and the weight percentage of each particle size in 97% magnesia is 35%, 22%, 18% and 25% respectively.

[0073] The lower inner core 4 is made of high-purity chrome-magnesium corundum castable, including the following raw material components in mass percentage: 30% fused white corundum with a particle size of 10mm≦<15mm, 10.07% fused white corundum with a particle size of 5mm≦<10mm, 8% fused white corundum with a particle size of 3mm≦<5mm, 11% fused white corundum with a particle size of 1mm≦<3mm, 8% fused white corundum with a particle size of 0.088mm≦<1mm, and 0.044mm≦ 10% of plate-like corundum fine powder <0.088mm, 4% of plate-like corundum micropowder <0.044mm, 0.8% of fused magnesia fine powder with particle size 0.088mm≦<0.5mm, 3% of fused magnesia micropowder with particle size ≦0.044mm, 6% of fused Cr2O3 micropowder, 4% of fused spinel micropowder with particle size <0.044mm, 5% of pure calcium aluminate cement, 0.1% of sodium hexametaphosphate, and 0.03% of heat-resistant steel fiber.

[0074] A method for preparing a composite high-life ladle nozzle seat brick for steelmaking and refining, comprising the following steps:

[0075] S1. Preparation of upper inner core 1 and lower inner core 4:

[0076] a. Weigh the raw materials according to the formula, put 96% magnesia and 97% magnesia as aggregate into the mixer, then put the phenolic resin, premix for 4 minutes, put 97% graphite and metal aluminum silicon powder into the mixer, mix for 18 minutes to obtain a mixture;

[0077] b. The mixed mixture was added to the mold for compression molding, first struck 3 times with a force of 2800kN, and then struck 6 times with a force of 6200kN, so that the inner core size reached the standard, to obtain an upper core 1 embryo and a lower core 4 embryo;

[0078] c. Dry the raw embryos of the upper inner core 1 and the lower inner core 4 in sections, bake them from room temperature at a heating rate of 40°C / h, and when the temperature reaches 200°C, continue to keep warm and bake for 10 hours, and then bake them at a cooling rate of 11°C / h for 12 hours to obtain the upper inner core 1 and the lower inner core 4, and assemble the upper inner core 1 and the lower inner core 4 to obtain the inner core.

[0079] S2. Preparation of green bricks for ladle nozzle seat:

[0080] A. After evenly brushing oil on the inner wall of the block mold, place it on the vibration table and put the inner core into the block mold;

[0081] B. After the high-purity chrome-magnesium corundum castable is prepared according to the components, dry-mix for 9 minutes, and after mixing evenly, add 5.5% of the total weight of water, wet-mix for 10 minutes, and mix evenly to obtain the mud;

[0082] C. Add the mud between the inner core and the base brick mold, vibrate while adding the mud until the mud is level with the upper edge of the base brick mold, and continue vibrating until the surface is dense and slurry is formed;

[0083] D. After curing for 3 days at a temperature of 20-25°C and a humidity greater than 90%, demoulding is performed to obtain the green bricks of the ladle nozzle seat.

[0084] S3. The green bricks of the ladle nozzle seat are heated from room temperature to 160°C at a heating rate of 10°C / h, and kept warm for 12 hours; then the green bricks are heated from 160°C to 240°C at a heating rate of 10°C / h, and kept warm for 12 hours; then the green bricks are heated from 240°C to 630°C at a heating rate of 15°C / h, and kept warm for 11 hours. The green bricks are then cooled naturally for 18 hours to obtain composite high-life ladle nozzle seat bricks for steelmaking and refining.

[0085] The composite high-life ladle nozzle seat brick for steelmaking and refining prepared in Example 3 has a service life of 93-96 times.

[0086] Performance testing:

[0087] The physical and chemical properties of the inner core and the outer casting prepared in Example 1 were tested, and the results are shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] As shown in Table 1, the inner core and the castings meet the standard requirements in all aspects. The inner core has low porosity, high bulk density, high compressive strength and high temperature flexural strength. The outer castings have high compressive strength at high temperatures, low thermal expansion, and good dimensional stability.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite high-life ladle nozzle seat brick for steelmaking and refining, characterized in that: It includes a seat brick inner core, which is cylindrical, and a flow steel hole is arranged in the center of the inner core from top to bottom. The inner core includes an upper inner core and a lower inner core that are aligned and fit together, and the upper inner core and the lower inner core are formed by machine pressing. A casting is arranged on the outer side of the inner core, and the casting is flush with the top end surface of the inner core. The bottom of the casting extends to the bottom of the inner core. A mounting hole is arranged in the center of the bottom of the casting, and the diameter of the mounting hole is larger than the diameter of the flow steel hole, and the mounting hole is coaxial with the flow steel hole.

2. The composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 1 is characterized in that: The height of the upper inner core is 175-190 mm, a boss is provided at the bottom center of the upper inner core, the height of the lower inner core is 200-210 mm, a groove is provided at the top center of the lower inner core, and the groove is aligned with the boss.

3. The composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 1 is characterized in that: The inner core comprises the following raw material components in weight percentage: 7-14% of 96% magnesia, 60-75% of 97% magnesia, 7-18% of 97% graphite, 4-7% of metal aluminum silicon powder, and 1-4% of phenolic resin.

4. The composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 3 is characterized in that: The particle size of the 96% magnesia sand is 9-24mm; the particle size of the 97% magnesia sand is 3-5mm, 1-3mm, 0-1mm and 200 mesh fine powder, and the weight percentage of each particle size in the 97% magnesia sand is 20-35%, 20-25%, 15-25% and 25-35% respectively.

5. The composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 1 is characterized in that: The casting adopts high-purity chrome-magnesium corundum casting material, including the following raw material components in mass percentage: 20-30% of fused white corundum with a particle size of 10mm≦<15mm, 10-12% of fused white corundum with a particle size of 5mm≦<10mm, 8-11% of fused white corundum with a particle size of 3mm≦<5mm, 9-11% of fused white corundum with a particle size of 1mm≦<3mm, 8-15% of fused white corundum with a particle size of 0.088mm≦<1mm, and plate-shaped corundum with a particle size of 0.044mm≦<0.088mm. Fine powder 10-13%, plate-shaped corundum powder with particle size <0.044mm 4-7%, fused magnesia fine powder with particle size 0.088mm≦<0.5mm 0.8-3.5%, fused magnesia powder with particle size ≦0.044mm 1.0-3.0%, fused Cr2O3 powder 4.0-6.0%, fused spinel powder with particle size <0.044mm 2.0-4.0%, pure calcium aluminate cement 3-5%, sodium hexametaphosphate 0.1-0.3%, and heat-resistant steel fiber 0.03-0.08%.

6. A method for preparing a composite long-life ladle nozzle seat brick for steelmaking and refining according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The upper inner core and the lower inner core are prepared by machine compression molding, and the upper inner core and the lower inner core are aligned and assembled to obtain an inner core; S2. The assembled inner core is placed in a block mold, and then a high-purity chromium-magnesium-corundum castable is poured between the inner core and the block mold to obtain a green embryo of a ladle nozzle block; S3. The green bricks of the ladle nozzle seat are baked and cooled to obtain composite high-life ladle nozzle seat bricks for steelmaking and refining.

7. The method for preparing the composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 6, characterized in that: The specific steps of step S1 include: a. Weigh the raw materials according to the formula, put 96% magnesia and 97% magnesia into the mixer, then put the phenolic resin, premix for 3-5min, put 97% graphite and metal aluminum silicon powder into the mixer, mix for 15-20min to obtain a mixture; b. The mixed material is added to a mold for compression molding to obtain an upper core embryo and a lower core embryo; c. Drying the upper inner core embryo and the lower inner core embryo in sections to obtain the upper inner core and the lower inner core, and aligning and assembling the upper inner core and the lower inner core to obtain the inner core.

8. The method for preparing the composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 7, characterized in that: The specific steps of the segmented drying in step c include: baking from room temperature at a heating rate of 35-40°C / h, when the temperature reaches 200°C, continuing to keep warm and bake for 8-10 hours, and then baking at a cooling rate of 11°C / h for 12 hours.

9. The method for preparing the composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 6, characterized in that: The specific steps of step S2 include: A. After evenly brushing oil on the inner wall of the block mold, place it on a vibration table and put the inner core into the block mold; B. After the high-purity chrome-magnesium-corundum castable is prepared according to the components, dry-mix for 4-9 minutes, and after mixing evenly, add 5-6% of the total weight of the material into water, wet-mix for 5-10 minutes, and mix evenly to obtain the mud; C. Add the mud between the inner core and the base brick mold, vibrate while adding the mud until the mud is flush with the upper edge of the base brick mold, and continue vibrating until the surface is dense and slurry is formed; D. After curing for 3-4 days at a temperature of 15-29°C and a humidity greater than 90%, demoulding is performed to obtain the green brick of the ladle nozzle seat.

10. The method for preparing the composite long-life ladle nozzle seat brick for steelmaking and refining according to claim 6, characterized in that: The specific steps of S3 include: heating the green brick of the ladle nozzle seat from room temperature to 140-160°C at a heating rate of 10°C / h, and keeping it warm for 12-24h; then heating from 140-160°C to 240-260°C at a heating rate of 10°C / h, and keeping it warm for 10-12h; then heating from 240-260°C to 600-650°C at a heating rate of 15°C / h, and keeping it warm for 10-12h, then stopping the fire and cooling naturally for 12-24h, so as to obtain the composite high-life ladle nozzle seat brick for steelmaking and refining.

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