A kind of KR stir head with castable, KR stir head preform and preparation method thereof

Abstract

The application provides a KR stirring head castable, a KR stirring head prefabricated part and a preparation method thereof. The KR stirring head castable comprises the following components in parts by mass: 25-45 parts of fused mullite, 2-15 parts of andalusite, 20-50 parts of tabular corundum, 2-15 parts of silicon carbide, 0.5-15 parts of alumina micropowder, 2-10 parts of cement, 0.02-0.18 parts of organic fiber, 1-8 parts of steel fiber, 0.05-2 parts of water reducing agent, 0.2-1.8 parts of metallic silicon powder and 0.01-0.5 parts of metallic aluminum powder. The KR stirring head castable, the KR stirring head prefabricated part and the preparation method thereof reduce the internal thermal stress of the material, prolong the service life of the castable, make the castable have good thermal shock resistance in intermittent operation, and have excellent properties such as erosion resistance, corrosion resistance and long service life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hot metal desulphurization, and particularly relates to a castable for a KR stirring head, a KR stirring head preform and a preparation method thereof. BACKGROUND

[0002] KR desulphurization is a widely used and relatively mature hot metal desulphurization method, which involves immersing a refractory stirring head into a hot metal ladle to stir the hot metal and generate a vortex, and adding a certain proportion of desulfurizer from a feeder into the ladle, so that the calcium oxide-based desulfurizing powder is fully contacted with the hot metal to achieve the purpose of desulphurization. KR method has excellent desulphurization kinetics, and the desulphurization rate can reach more than 90%, which can achieve very deep desulphurization. The desulphurization effect is relatively stable, and has the advantages of high efficiency and low consumption, and is suitable for smelting of very low sulfur steel.

[0003] The refractory stirring head is made of refractory material cast on the surface of steel structure and baked. The stirring paddle core is a steel structure, and the working lining is integrally cast by refractory castable. At present, the existing KR stirring paddle has insufficient erosion resistance and corrosion resistance, and the main damage part of the KR stirring paddle is the molten loss and spalling of the blade. In the middle and later stages of use, due to more erosion of the blade, the stirring effect is obviously decreased, and the desulphurization effect must be ensured by prolonging the stirring time, increasing the rotating speed and other methods. The repair workload and the amount of repair material increase, and the labor intensity of workers increases. Moreover, compared with the early stage, the temperature of the stirring paddle rises sharply in use, the expansion amount of the steel structure increases, the expansion amount difference between the refractory and the steel structure is large, and the stirring head spalling is serious.

[0004] Therefore, it is necessary to provide a KR stirring head castable with erosion resistance and corrosion resistance. SUMMARY

[0005] The technical problem solved by the present application is to provide a KR stirring head castable, a KR stirring head preform and a preparation method thereof, which reduces the internal thermal stress of the material, prolongs the service life of the castable, has good thermal shock resistance in intermittent operation, and has excellent properties such as erosion resistance, corrosion resistance and long service life.

[0006] In order to solve the above problems, the first aspect of the present application provides a KR stirring head castable, which comprises the following components by mass fraction:

[0007] Electric melting mullite 25-45 parts, andalusite 2-15 parts, tabular corundum 20-50 parts, silicon carbide 2-15 parts, alumina micropowder 0.5-15 parts, cement 2-10 parts, organic fiber 0.02-0.18 parts, steel fiber 1-8 parts, water reducing agent 0.05-2 parts, metallic silicon powder 0.2-1.8 parts, and metallic aluminum powder 0.01-0.5 parts.

[0008] Preferably, the KR mixing head with castable includes the following components by mass fraction:

[0009] Electric-melting mullite 30-40 parts, Andalusite 4-10 parts, tabular corundum 30-40 parts, silicon carbide 5-10 parts, alumina micropowder 1-10 parts, cement 3-6 parts, organic fiber 0.05-0.15 parts, steel fiber 3-5 parts, water reducing agent 0.1-1 part, metallic silicon powder 0.5-1.5 parts, and metallic aluminum powder 0.01-0.1 part.

[0010] Preferably, the electric-melting mullite includes electric-melting mullite with a particle size of 20mm≥particle size>8mm, electric-melting mullite with a particle size of 8mm≥particle size>5mm, and electric-melting mullite with a particle size of 5mm≥particle size>3mm;

[0011] The mass ratio of electric-melting mullite with a particle size of 20mm≥particle size>8mm, electric-melting mullite with a particle size of 8mm≥particle size>5mm, and electric-melting mullite with a particle size of 5mm≥particle size>3mm is 1-3:1-3:2-4;

[0012] The content of alumina in the electric-melting mullite is >70wt%.

[0013] Preferably, the tabular corundum includes tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh;

[0014] The mass ratio of tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh is 3-4:3-4:3-4;

[0015] The content of alumina in the tabular corundum is >99wt%.

[0016] Preferably, the mass ratio of Andalusite to alumina micropowder is 1:0.6-2.

[0017] Preferably, the mass ratio of silicon carbide to metallic silicon powder is 6-9:1.

[0018] Preferably, the particle size of Andalusite is 3mm≥particle size>1mm; the content of alumina in Andalusite is >57wt%.

[0019] The particle size of silicon carbide is 325 mesh.

[0020] The alumina micropowder includes alumina micropowder with a particle size of 1μm and alumina micropowder with a particle size of 3μm; the mass ratio of active alumina micropowder with a particle size of 1μm to active alumina micropowder with a particle size of 3μm is 1-2:1-2.

[0021] The particle size of the metal silicon powder is 325 mesh; and the particle size of the metal aluminum powder is 200 mesh.

[0022] Preferably, the organic fiber is a high molecular weight polyethylene fiber; and the steel fiber is a 446# steel fiber.

[0023] The water reducing agent is one or a mixture of both of sodium tripolyphosphate and sodium hexametaphosphate.

[0024] The second aspect of the present application provides a KR stir head preform prepared from the KR stir head castable described above.

[0025] The third aspect of the present application provides a preparation method of the KR stir head preform described above, comprising the following steps:

[0026] S1. Mixing the KR stir head castable with water to obtain a mixed material;

[0027] S2. Injecting the mixed material into a mold to form a shaped material;

[0028] S3. Successively curing and baking the shaped material to obtain the KR stir head preform.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The KR stir head castable of the present application mainly uses high-purity capacitive mullite as aggregate, and is combined with tabular corundum and andalusite. Andalusite can be converted into mullite and silicon dioxide at high temperature, and is accompanied by a volume expansion of about 7.5%, thereby reducing the expansion difference between the refractory body of the stir head and the steel structure at high temperature, reducing the internal thermal stress of the material, and reducing the risk of cracking of the refractory by the steel structure. At the same time, the silicon dioxide decomposed from andalusite reacts with aluminum oxide powder to form part of mullite, thereby increasing the content of mullite in the material; a certain content of silicon carbide can improve the thermal shock resistance of the material and prolong the service life of the stir head; further adding metal silicon powder, which can prevent the oxidation of silicon carbide, thereby helping to improve the thermal shock resistance of the material. The KR stir head working lining prepared from the KR stir head castable of the present application has excellent properties of erosion resistance, corrosion resistance, and long service life, and has good thermal shock resistance in intermittent use operation. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] The first aspect of the embodiment of the present application provides a castable for KR stirrer, which comprises the following components in mass fraction:

[0033] Electric melting mullite 25-45 parts, andalusite 2-15 parts, tabular corundum 20-50 parts, silicon carbide 2-15 parts, alumina micropowder 0.5-15 parts, cement 2-10 parts, organic fiber 0.02-0.18 parts, steel fiber 1-8 parts, water reducing agent 0.05-2 parts, metallic silicon powder 0.2-1.8 parts, and metallic aluminum powder 0.01-0.5 parts.

[0034] The castable for KR stirrer of the embodiment of the present application mainly comprises high-purity electric capacity mullite, tabular corundum and andalusite. The andalusite can be converted into mullite and silicon dioxide at high temperature, and is accompanied by a volume expansion of about 7.5%, thereby reducing the expansion difference between the refractory body of the stirrer and the steel structure at high temperature, reducing the internal thermal stress of the material, and reducing the risk of cracking of the refractory by the steel structure. At the same time, the silicon dioxide decomposed from the andalusite reacts with the alumina micropowder to generate part of the mullite, thereby increasing the content of mullite in the material. A certain content of silicon carbide can improve the thermal shock resistance of the material and prolong the service life of the stirrer. Further, the metallic silicon powder is added, which can prevent the oxidation of silicon carbide, thereby helping to improve the thermal shock resistance of the material. The KR stirrer working lining prepared from the castable for KR stirrer of the embodiment of the present application has excellent properties of erosion resistance, corrosion resistance and long service life, and has good thermal shock resistance in intermittent use operation.

[0035] In some embodiments, the castable for KR stirrer comprises the following components in mass fraction:

[0036] Electric melting mullite 30-40 parts, andalusite 4-10 parts, tabular corundum 30-40 parts, silicon carbide 5-10 parts, alumina micropowder 1-10 parts, cement 3-6 parts, organic fiber 0.05-0.15 parts, steel fiber 3-5 parts, water reducing agent 0.1-1 parts, metallic silicon powder 0.5-1.5 parts, and metallic aluminum powder 0.01-0.1 parts.

[0037] The mass fraction of each component in the castable for KR stirrer is further optimized in the embodiment of the present application. When the components in the above mass fraction are used, the KR stirrer working lining prepared therefrom has better erosion resistance, corrosion resistance and thermal shock resistance, and has a longer service life.

[0038] In some embodiments, the mass ratio of andalusite to alumina micropowder is 1:0.6-2. Andalusite can be converted into mullite and silica at high temperature, accompanied by a volume expansion of about 7.5%, while silica and alumina micropowder can further react to form mullite at a certain ratio, which can improve the erosion resistance and corrosion resistance of the castable. If the amount of andalusite is too large, the volume expansion of the working lining of the stirring head is too large, which is not conducive to reducing the expansion difference between the refractory body of the stirring head and the steel structure at high temperature, and can cause the working lining of the stirring head to crack. If the amount of andalusite is too small, or the ratio of andalusite to alumina micropowder is not appropriate, the generation of mullite phase will be reduced, which is not conducive to improving the erosion resistance and corrosion resistance of the castable. Research has found that the mass ratio of andalusite to alumina micropowder in the above range can make the KR stirring head castable have better erosion resistance, higher corrosion resistance, and longer service life, and be less prone to swelling and cracking.

[0039] In some embodiments, the mass ratio of silicon carbide to silicon metal powder is 6-9:1.

[0040] In some embodiments, the electrically fused mullite includes electrically fused mullite with a particle size of 20mm≥particle size>8mm, electrically fused mullite with a particle size of 8mm≥particle size>5mm, and electrically fused mullite with a particle size of 5mm≥particle size>3mm; the mass ratio of electrically fused mullite with a particle size of 20mm≥particle size>8mm, electrically fused mullite with a particle size of 8mm≥particle size>5mm, and electrically fused mullite with a particle size of 5mm≥particle size>3mm is 1-3:1-3:2-4. When the electrically fused mullite adopts the above particle size grading, the strength of the stirring head working lining prepared from the castable is higher.

[0041] In some embodiments, the content of alumina in the electrically fused mullite is >70wt%.

[0042] In some embodiments, the particle size of andalusite is 3mm≥particle size>1mm; the content of alumina in andalusite is >57wt%.

[0043] In some embodiments, the tabular corundum includes tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh; the mass ratio of tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh is 3-4:3-4:3-4.

[0044] In some embodiments, the content of alumina in the tabular corundum is >99wt%.

[0045] In some embodiments, the particle size of silicon carbide is 325 mesh.

[0046] In some embodiments, the alumina micropowder includes alumina micropowder with a particle size of 1 μm and alumina micropowder with a particle size of 3 μm; the mass ratio of the active alumina micropowder with a particle size of 1 μm to the active alumina micropowder with a particle size of 3 μm is 1-2:1-2.

[0047] In some embodiments, the particle size of the metal silicon powder is 325 mesh; the particle size of the metal aluminum powder is 200 mesh.

[0048] In some embodiments, the organic fiber can adopt various types of existing explosion-proof organic fibers, preferably, the organic fiber is a high molecular weight polyethylene fiber.

[0049] In some embodiments, the steel fiber can adopt various types of existing steel fibers, preferably, the steel fiber is a 446# steel fiber.

[0050] In some embodiments, the water reducing agent can adopt various types of existing water reducing agents, preferably, the water reducing agent is one or a mixture of both of sodium tripolyphosphate and sodium hexametaphosphate.

[0051] The second aspect of the present application provides a KR stirring head prefabricated piece prepared by using the KR stirring head castable described above. The KR stirring head prefabricated piece of the embodiment of the present application has excellent properties of erosion resistance, corrosion resistance, and long service life, and has good thermal shock resistance in intermittent operation.

[0052] The third aspect of the present application provides a preparation method of the KR stirring head prefabricated piece described above, including the following steps:

[0053] S1. mixing each of the KR stirring head castables with water to obtain a mixed material;

[0054] S2. injecting the mixed material into a mold to form a shaped material;

[0055] S3. sequentially performing curing and baking treatment on the shaped material to obtain the KR stirring head prefabricated piece.

[0056] In some embodiments, the curing is mold curing at room temperature (20-30℃) for 12-36 h, and demolding curing for 12-36 h.

[0057] Further, the temperature of the baking treatment is 300-340℃, and the time of the baking treatment is 24-72 h.

[0058] In each of the following embodiments, the content of alumina in the electrically fused mullite is >70wt%; the content of alumina in the andalusite is >57wt%; and the content of alumina in the tabular corundum is >99wt%.

[0059] Example 1

[0060] The KR stirring head casting material described in the embodiment comprises the following components in mass fraction:

[0061] 20mm≥particle size>8mm of fused mullite 10 parts, 8mm≥particle size>5mm of fused mullite 10 parts, 5mm≥particle size>3mm of fused mullite 15 parts, 3mm≥particle size>1mm of andalusite 7.5 parts, 1mm≥particle size>0mm of tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 7.5 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 7.5 parts, alumina micropowder with particle size of 1μm 3 parts, alumina micropowder with particle size of 3μm 3 parts, cement 4 parts, high molecular weight polyethylene fiber 0.12 parts, 446# steel fiber 4 parts, sodium tripolyphosphate 0.35 parts, metal silicon powder with particle size of 325 mesh 1 part, metal aluminum powder with particle size of 200 mesh 0.03 parts.

[0062] The preparation method of the KR stirring head preform of the embodiment comprises the following steps:

[0063] S1. The raw materials of the casting material are mixed according to the set proportion and particle size, and then dry-mixed for 5 minutes, and 5wt% of water is additionally stirred for 1 minute to obtain a mixture;

[0064] S2. The mixture is placed in a mold (including the steel structural part of the stirring head) and vibrated to form, so as to discharge the air bubbles in the casting material until the casting material is fully vibrated and compacted, and then point-vibrated for 4-6 times, and then left to stand to obtain a formed material;

[0065] S3. The formed material is cured together with the mold at 25℃ for 24 hours, and then naturally cured for 24 hours after demolding to obtain a semi-finished product of the preform; the semi-finished product is heated to 320℃ according to a curve in an oven, and the heating time is 48 hours to obtain a KR stirring head preform.

[0066] Example 2

[0067] The KR stirring head casting material described in the embodiment comprises the following components in mass fraction:

[0068] 20mm≥ particle size > 8mm fused mullite 10 parts, 8mm≥ particle size > 5mm fused mullite 15 parts, 5mm≥ particle size > 3mm fused mullite 10 parts, 3mm≥ particle size > 1mm andalusite 7.5 parts, 1mm≥ particle size > 0mm tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 7.5 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 7.5 parts, alumina micropowder with particle size of 1 μm 3 parts, alumina micropowder with particle size of 3 μm 3 parts, cement 4 parts, high molecular weight polyethylene fiber 0.12 parts, 446# steel fiber 4 parts, sodium tripolyphosphate 0.35 parts, metal silicon powder with mesh of 325 1 part, metal aluminum powder with mesh of 200 0.03 parts.

[0069] The preparation method of the KR stirrer head preform of the present embodiment is the same as that of Embodiment 1.

[0070] Embodiment 3

[0071] The castable for KR stirrer head of the present embodiment comprises the following components in mass fraction:

[0072] 20mm≥ particle size > 8mm fused mullite 10 parts, 8mm≥ particle size > 5mm fused mullite 15 parts, 5mm≥ particle size > 3mm fused mullite 10 parts, 3mm≥ particle size > 1mm andalusite 7.5 parts, 1mm≥ particle size > 0mm tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 7.5 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 7.5 parts, alumina micropowder with particle size of 1 μm 3 parts, alumina micropowder with particle size of 3 μm 3 parts, cement 5 parts, high molecular weight polyethylene fiber 0.12 parts, 446# steel fiber 3 parts, sodium tripolyphosphate 0.35 parts, metal silicon powder with mesh of 325 1 part, metal aluminum powder with mesh of 200 0.03 parts.

[0073] The preparation method of the KR stirrer head preform of the present embodiment is the same as that of Embodiment 1.

[0074] Embodiment 4

[0075] The castable for KR stirrer head of the present embodiment comprises the following components in mass fraction:

[0076] 20mm≥ particle size > 8mm fused mullite 10 parts, 8mm≥ particle size > 5mm fused mullite 10 parts, 5mm≥ particle size > 3mm fused mullite 10 parts, 3mm≥ particle size > 1mm andalusite 10 parts, 1mm≥ particle size > 0mm tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 10 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 8.5 parts, alumina micropowder with particle size of 1 μm 3 parts, alumina micropowder with particle size of 3 μm 3 parts, cement 3 parts, high molecular weight polyethylene fiber 0.09 parts, 446# steel fiber 3 parts, sodium tripolyphosphate 1 part, metal silicon powder with particle size of 325 mesh 1.4 parts, metal aluminum powder with particle size of 200 mesh 0.01 parts.

[0077] The preparation method of the KR stirrer head preform of the present embodiment is the same as that of Embodiment 1.

[0078] Embodiment 5

[0079] The castable for KR stirrer head of the present embodiment comprises the following components in mass fraction:

[0080] 20mm≥ particle size > 8mm fused mullite 10 parts, 8mm≥ particle size > 5mm fused mullite 10 parts, 5mm≥ particle size > 3mm fused mullite 10 parts, 3mm≥ particle size > 1mm andalusite 10 parts, 1mm≥ particle size > 0mm tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 10 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 8.5 parts, alumina micropowder with particle size of 1 μm 3 parts, alumina micropowder with particle size of 3 μm 3 parts, cement 3 parts, high molecular weight polyethylene fiber 0.09 parts, 446# steel fiber 3 parts, sodium tripolyphosphate 1 part, metal silicon powder with particle size of 325 mesh 1.4 parts, metal aluminum powder with particle size of 200 mesh 0.01 parts.

[0081] The preparation method of the KR stirrer head preform of the present embodiment is the same as that of Embodiment 1.

[0082] Embodiment 6

[0083] The castable for KR stirrer head of the present embodiment comprises the following components in mass fraction:

[0084] 20mm≥ particle size > 8mm of fused mullite 10 parts, 8mm≥ particle size > 5mm of fused mullite 10 parts, 5mm≥ particle size > 3mm of fused mullite 20 parts, 3mm≥ particle size > 1mm of andalusite 5 parts, 1mm≥ particle size > 0mm of tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 5 parts, tabular corundum fine powder with particle size of 325 mesh 5 parts, silicon carbide with particle size of 325 mesh 5 parts, alumina micropowder with particle size of 1 μm 5 parts, alumina micropowder with particle size of 3 μm 5 parts, cement 6 parts, high molecular weight polyethylene fiber 0.05 parts, 446# steel fiber 3 parts, sodium tripolyphosphate 0.1 part, metal silicon powder with mesh of 325 0.8 parts, metal aluminum powder with mesh of 200 0.05 parts.

[0085] The preparation method of the KR stir head preform of the present embodiment is the same as that of Embodiment 1.

[0086] Embodiment 7

[0087] The castable for KR stir head of the present embodiment comprises the following components in mass fraction:

[0088] 20mm≥ particle size > 8mm of fused mullite 10 parts, 8mm≥ particle size > 5mm of fused mullite 10 parts, 5mm≥ particle size > 3mm of fused mullite 5 parts, 3mm≥ particle size > 1mm of andalusite 15 parts, 1mm≥ particle size > 0mm of tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 20 parts, tabular corundum fine powder with particle size of 325 mesh 10 parts, silicon carbide with particle size of 325 mesh 2 parts, alumina micropowder with particle size of 1 μm 0.3 parts, alumina micropowder with particle size of 3 μm 0.3 parts, cement 2 parts, high molecular weight polyethylene fiber 0.18 parts, 446# steel fiber 2 parts, sodium tripolyphosphate 2 parts, metal silicon powder with mesh of 325 0.72 parts, metal aluminum powder with mesh of 200 0.5 parts.

[0089] The preparation method of the KR stir head preform of the present embodiment is the same as that of Embodiment 1.

[0090] Embodiment 8

[0091] The castable for KR stir head of the present embodiment comprises the following components in mass fraction:

[0092] 20 parts of fused mullite with particle size of 20 mm > 8 mm, 20 parts of fused mullite with particle size of 8 mm > 5 mm, 3 parts of fused mullite with particle size of 5 mm > 3 mm, 2 parts of andalusite with particle size of 3 mm > 1 mm, 10 parts of tabular corundum particles with particle size of 1 mm > 0 mm, 5 parts of tabular corundum fine powder with particle size of 200 mesh, 5 parts of tabular corundum fine powder with particle size of 325 mesh, 13 parts of silicon carbide with particle size of 325 mesh, 6 parts of alumina micropowder with particle size of 1 μm, 6 parts of alumina micropowder with particle size of 3 μm, 2 parts of cement, 0.02 parts of high molecular weight polyethylene fiber, 6 parts of 446# steel fiber, 0.05 parts of sodium tripolyphosphate, 1.8 parts of metallic silicon powder with particle size of 325 mesh, and 0.13 parts of metallic aluminum powder with particle size of 200 mesh.

[0093] The KR stirrer head preform of the present embodiment is prepared in the same manner as in Example 1.

[0094] Example 9

[0095] The KR stirrer head castable of the present embodiment is different from that of Example 1 in that the mass ratio of andalusite to alumina micropowder is different, and the other components and mass fractions are the same as those of Example 1. In the present embodiment, andalusite is 8.5 parts, alumina micropowder with particle size of 1 μm is 2.5 parts, and alumina micropowder with particle size of 3 μm is 2.5 parts.

[0096] Example 10

[0097] The KR stirrer head castable of the present embodiment is different from that of Example 1 in that the mass ratio of andalusite to alumina micropowder is different, and the other components and mass fractions are the same as those of Example 1. In the present embodiment, andalusite is 4.5 parts, alumina micropowder with particle size of 1 μm is 4.5 parts, and alumina micropowder with particle size of 3 μm is 4.5 parts.

[0098] Example 11

[0099] The KR stirrer head castable of the present embodiment is different from that of Example 1 in that the mass ratio of andalusite to alumina micropowder is different, and the other components and mass fractions are the same as those of Example 1. In the present embodiment, andalusite is 9.5 parts, alumina micropowder with particle size of 1 μm is 2 parts, and alumina micropowder with particle size of 3 μm is 2 parts.

[0100] Example 12

[0101] The KR stirrer head castable of the present embodiment is different from that of Example 1 in that the mass ratio of andalusite to alumina micropowder is different, and the other components and mass fractions are the same as those of Example 1. In the present embodiment, andalusite is 4 parts, alumina micropowder with particle size of 1 μm is 4.75 parts, and alumina micropowder with particle size of 3 μm is 4.75 parts.

[0102] Example 13

[0103] The difference between the castable for KR stirring head described in this example and example 1 is that the mass ratio of silicon carbide to metal silicon powder is different, and the rest of the components and mass fractions are the same as those in example 1. In this example, the mass of silicon carbide is 7.3 parts, and the mass of metal silicon powder is 1.2 parts.

[0104] Example 14

[0105] The difference between the castable for KR stirring head described in this example and example 1 is that the mass ratio of silicon carbide to metal silicon powder is different, and the rest of the components and mass fractions are the same as those in example 1. In this example, the mass of silicon carbide is 7.6 parts, and the mass of metal silicon powder is 0.9 parts.

[0106] Example 15

[0107] The difference between the castable for KR stirring head described in this example and example 1 is that the mass ratio of silicon carbide to metal silicon powder is different, and the rest of the components and mass fractions are the same as those in example 1. In this example, the mass of silicon carbide is 7 parts, and the mass of metal silicon powder is 1.5 parts.

[0108] Example 16

[0109] The difference between the castable for KR stirring head described in this example and example 1 is that the mass ratio of silicon carbide to metal silicon powder is different, and the rest of the components and mass fractions are the same as those in example 1. In this example, the mass of silicon carbide is 8 parts, and the mass of metal silicon powder is 0.5 parts.

[0110] Comparative Example 1

[0111] The castable for KR stirring head of this comparative example comprises the following components in mass fractions:

[0112] 20mm≥particle size>8mm of fused mullite 10 parts, 8mm≥particle size>5mm of fused mullite 10 parts, 5mm≥particle size>3mm of fused mullite 15 parts, 1mm≥particle size>0mm of tabular corundum particles 20 parts, tabular corundum fine powder with particle size of 200 mesh 7.5 parts, tabular corundum fine powder with particle size of 325 mesh 7 parts, silicon carbide with particle size of 325 mesh 7.5 parts, alumina micropowder with particle size of 1 μm 3 parts, alumina micropowder with particle size of 3 μm 3 parts, cement 4 parts, high molecular weight polyethylene fiber 0.12 parts, 446# steel fiber 4 parts, sodium tripolyphosphate 0.35 parts, metal silicon powder with particle size of 325 mesh 1 part, metal aluminum powder with particle size of 200 mesh 0.03 parts.

[0113] The strength performance, thermal shock resistance, and cracking of the refractory and steel structure at the use temperature of the stir head preform obtained in each of the above examples and comparative examples were tested. The cracking test conditions were 1400°C for 3h. The results are shown in Table 1 below. Comparative Example 1 differs from Example 1 in that no microcrystalline andalusite is added. In the test conditions, the refractory and steel structure cracked obviously, and the erosion resistance, corrosion resistance, and thermal shock resistance of the stir head preform were significantly lower than those of Example 1 (the erosion resistance and corrosion resistance are mainly reflected by the bending strength and compressive strength performance). The performance of the stir head preform of each of the examples of the present application is significantly improved compared with Comparative Example 1. Examples 1-6 differ from Examples 7 and 8 in the mass fraction of each component. The strength performance, erosion resistance, corrosion resistance, and thermal shock resistance of Examples 1-6 are significantly better than those of Examples 7 and 8, indicating that the mass fraction of each component in Examples 1-6 is in the preferred range.

[0114] Examples 1, 9-12 differ from each other in the mass ratio of microcrystalline andalusite to alumina powder. The strength performance, erosion resistance, corrosion resistance, and thermal shock resistance of the stir head preforms of Examples 1, 9, and 10 are significantly better, and the stir head working lining is less likely to crack and expand. In Example 11, the proportion of microcrystalline andalusite is too high, the volume expansion of the stir head working lining is too large, and the stir head working lining cracks to some extent, and the strength performance and thermal shock resistance are also reduced. In Example 12, the proportion of microcrystalline andalusite is too low, and the generation of mullite phase is less, so the strength performance, erosion resistance, and corrosion resistance are poor.

[0115] Examples 1, 13-16 differ from each other in the mass ratio of silicon carbide to metallic silicon powder. The thermal shock resistance of the stir head preforms of Examples 1, 13, and 14 is better. In Examples 15 and 16, the mass ratio of silicon carbide to metallic silicon powder is too low or too high, and the metallic silicon powder is oxidized more, so the thermal shock resistance of the stir head preform is reduced.

[0116] Table 1

[0117]

[0118] Obviously, the above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, those skilled in the art can make other different forms of changes or modifications. All embodiments do not need to be exhausted here. The obvious changes or modifications derived therefrom are still within the protection scope of the present application.

Claims

1. A castable for a KR stirrer, characterized by, The components include the following mass fractions: electro-fused mullite 30-40 parts, andalusite 4-10 parts, tabular corundum 30-40 parts, silicon carbide 5-10 parts, alumina micropowder 1-10 parts, cement 3-6 parts, organic fiber 0.05-0.15 parts, steel fiber 3-5 parts, water reducing agent 0.1-1 part, metallic silicon powder 0.5-1.5 parts, and metallic aluminum powder 0.01-0.1 part; the mass ratio of andalusite to alumina micropowder is 1:0.6-2; the mass ratio of silicon carbide to metallic silicon powder is 6-9:1; the electro-fused mullite includes electro-fused mullite with a particle size of 20mm≥particle size>8mm, electro-fused mullite with a particle size of 8mm≥particle size>5mm, and electro-fused mullite with a particle size of 5mm≥particle size>3mm; the mass ratio of electro-fused mullite with a particle size of 20mm≥particle size>8mm, electro-fused mullite with a particle size of 8mm≥particle size>5mm, and electro-fused mullite with a particle size of 5mm≥particle size>3mm is 1-3:1-3:2-4; the content of alumina in the electro-fused mullite is >70wt%; the tabular corundum includes tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh; the mass ratio of tabular corundum particles with a particle size of 1mm≥particle size>0mm, tabular corundum fine powder with a particle size of 200 mesh, and tabular corundum fine powder with a particle size of 325 mesh is 3-4:3-4:3-4; the content of alumina in the tabular corundum is >99wt%; the particle size of andalusite is 3mm≥particle size>1mm; the content of alumina in andalusite is >57wt%; the particle size of silicon carbide is 325 mesh; the alumina micropowder includes active alumina micropowder with a particle size of 1μm and active alumina micropowder with a particle size of 3μm; the mass ratio of active alumina micropowder with a particle size of 1μm to active alumina micropowder with a particle size of 3μm is 1-2:1-2; the particle size of the metallic silicon powder is 325 mesh; the particle size of the metallic aluminum powder is 200 mesh.

2. The KR stir head castable according to claim 1, characterized in that: the organic fiber is a high-molecular-weight polyethylene fiber; the steel fiber is marked as 446#; the water reducing agent is one or a mixture of both of sodium tripolyphosphate and sodium hexametaphosphate.

3. A KR stir head preform prepared by using the KR stir head castable according to claim 1 or 2.

4. A method of making a KR stirrer head preform as claimed in claim 3, characterized in that, including the following steps: S1. mixing the components of the KR stir head castable with water to obtain a mixture; S2. injecting the mixture into a mold to perform molding to obtain a molded material; S3. sequentially performing curing and baking treatment on the molded material to obtain the KR stir head preform.

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