Tundish dry material and preparation method thereof

Abstract

The invention belongs to the technical field of refractory material preparation, and particularly relates to a tundish dry material and a preparation method thereof. The tundish dry material consists of the following raw materials: a material A, a material B, magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder, silica powder, nano titanium oxide and nano zirconium oxide. According to the tundish dry material, the material A and the material B are compounded for use, the material A plays a role in framework continuity, the material B plays a role in nanometer blocking, a mixture of magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silica powder serves as a sintering agent, and it is ensured that the tundish dry material has excellent breaking strength; and nano titanium oxide and nano zirconium oxide are added to further improve the slag penetration resistance of the prepared tundish dry material, so that the synergistic effect among the raw materials ensures that the prepared tundish dry material has excellent breaking strength and slag penetration resistance.

Description

Technical Field

[0001] This invention belongs to the field of refractory material preparation technology, specifically relating to a dry tundish material and its preparation method. Background Technology

[0002] The tundish is a transitional device between the crystallizer and the ladle in the continuous casting process of steelmaking. Using the tundish allows molten steel to be injected into the crystallizer more effectively and smoothly, ensuring the stability of the molten steel. Therefore, the tundish plays a crucial role in the steelmaking process. The refractory lining of the tundish mainly consists of an insulation layer, a permanent layer, and a working layer.

[0003] Dry refractory lining in tundishes is the material used as the working lining layer. It comes into direct contact with molten steel and slag and is an unshaped refractory material formed by vibration without the addition of water or liquid binders. Under vibration, the material forms a dense and uniform whole. Upon heating, it gains strength through thermosetting binders or ceramic sintering agents. Dry vibratory refractory lining consists of refractory aggregates, powders, sintering agents, and additives. Its characteristics include: easy flow under vibration; the powders can fill the tiny pores between particles even under very small vibration forces, resulting in a dense body with high packing density. During use, heating forms a working surface with a certain strength, while the non-working surface remains partially unsintered, retaining its original dense packing structure. This structure helps reduce stress caused by expansion or contraction; helps prevent crack propagation and extension; helps prevent the intrusion of molten metal; and facilitates unpacking and cleaning. This material is applied on-site using a vibration method, which is simple to apply, has a short construction period, requires no curing or baking, and can be directly and quickly heated to sinter the working layer for use.

[0004] Currently, the solid phenolic resin-bonded dry tundish charge widely used in steel plants is a refractory material developed primarily from magnesia, with added calcium-containing materials, various sintering aids, and high-temperature modifiers. Because dry tundish charges are water-free and contain no large amounts of high-temperature, low-melting-point substances, they have a long service life. However, the residual carbon and hydrogen produced during the baking and use of solid phenolic resin in dry tundish charges can increase the carbon and hydrogen content of the molten steel, affecting the quality of the billet. Furthermore, it generates large amounts of harmful and irritating gases, polluting the environment and failing to meet the requirements for clean steelmaking and high-quality, environmentally friendly steel billet production.

[0005] Currently, dry tundish materials used in continuous casting generally suffer from low strength and short service life (number of consecutive castings). In particular, because dry tundish materials contain trace amounts of carbon, water, phenols, aldehydes, etc., they are prone to causing secondary pollution to the molten steel in the tundish (the carbon and other elements contained in the product can affect the purity of the molten steel). Furthermore, hydration and cracking sometimes occur during the baking process (and may even produce a small number of cracked scraps). Therefore, it is necessary to develop a new type of dry tundish material. Summary of the Invention

[0006] The purpose of this invention is to provide a dry tundish material with excellent flexural strength and slag penetration resistance. In addition, this invention also provides a method for its preparation.

[0007] The dry intermediate ladle material of this invention, by mass percentage, comprises the following raw materials: Material A 63-65%, Material B 26.0-28.2%, Magnesium dihydrogen phosphate 3.8-4.0%, Activated magnesium oxide 0.2%, Micron-sized glass powder 0.7-0.9%, Silica powder 3.0-3.2%, Nano titanium dioxide 0.4-0.5%, and Nano zirconium oxide 0.4-0.5%; Material A, by mass percentage, comprises the following raw materials: Magnesia olivine 48%, Fused magnesium calcium sand 27%, and Magnesia aluminum spinel hollow spheres 25%, wherein, when distributed according to particle size, 3mm ≤ particle size < The raw material with a particle size of 5mm contains 17% forsterite, 10% fused magnesia-calcium sand, and 8% hollow magnesia-alumina spinel spheres; the raw material with a particle size of 1mm ≤ particle size < 3mm contains 17% forsterite, 10% fused magnesia-calcium sand, and 12% hollow magnesia-alumina spinel spheres; the raw material with a particle size of 0.074mm ≤ particle size ≤ 1mm contains 14% forsterite, 7% fused magnesia-calcium sand, and 5% magnesia-alumina spinel spheres; the B material is a mixture of 53% forsterite, 25% fused magnesia-calcium sand, and 22% hollow magnesia-alumina spinel spheres by mass percentage, which is then ground and sieved to control the particle size of the mixture to ≤ 0.074mm.

[0008] in: The manufacturer of the activated magnesium oxide is Hebei Magnesium God Technology Co., Ltd., and the model is Activated Magnesium Oxide Class I Active-120.

[0009] The method for preparing the micron-sized glass powder is as follows: calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate are mixed and passed through a 60-mesh sieve. The mixture is then melted at 1350℃ for 30 minutes to obtain molten glass. The molten glass is poured into deionized water at 20℃ for water quenching, then dried at 120℃ for 2 hours and crushed. Finally, it is wet-milled to d50=10 microns and spray-dried to obtain micron-sized glass powder.

[0010] In the preparation process of the micron-sized glass powder, the mass ratio of calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate is 41.76 : 15.35 : 44.68 : 2.72 : 0.42 : 0.46.

[0011] The micron-sized glass powder has the following chemical composition by mass percentage: CaO 29.3%, B2O3 10.8%, SiO2 56.2%, Al2O3 2.1%, MgO 0.5%, P2O5 0.4%, Fe2O3 0.5%, Na2O 0.2%.

[0012] The wet ball milling process involves adding ethanol to the ball mill. The mass ratio of the crushed glass powder, ethanol, and zirconium balls is 1:1.1:4. The wet ball milling speed is 300 r / min, and the wet ball milling time is 3.5 h.

[0013] The spray drying process involves an inlet air temperature of 210°C, an outlet air temperature of 90°C, a feed rate of 12 mL / min, and a residence time of 12 s.

[0014] The preparation method of the intermediate bag dry material of the present invention consists of the following steps: (1) The magnesium olivine, fused magnesium calcium sand and magnesium aluminum spinel hollow spheres are batched according to the particle size of 3mm≤particle size<5mm, 1mm≤particle size<3mm and 0.074mm<particle size≤1mm, and then mixed to prepare material A; (2) By mass percentage, 53% of magnesium olivine, 25% of fused magnesium calcium sand and 22% of magnesium aluminum spinel hollow spheres are mixed, ground and sieved to control the particle size of the mixture to ≤0.074mm, and material B is prepared. (3) Mix magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder evenly, and then add nano titanium oxide and nano zirconium oxide to mix and prepare a mixture. (4) Mix A material, B material and the mixture to prepare the intermediate dry material.

[0015] Wherein: the mixing time in step (1) is 10-12 min.

[0016] In step (3), magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder are mixed evenly for 5-7 minutes. Then, nano-titanium oxide and nano-zirconia are added and mixed for 5-7 minutes.

[0017] The mixing time in step (4) is 10-12 min.

[0018] Compared with the prior art, the present invention has the following advantages: (1) The tundish dry material of the present invention uses material A and material B in combination. Material A plays a continuous role in the skeleton, and material B plays a nano-blocking role. A mixture of magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder is used as a sintering agent to ensure that the tundish dry material has excellent flexural strength. Nano titanium oxide and nano zirconium oxide are added to further improve the slag penetration resistance of the prepared tundish dry material. Thus, the raw materials work synergistically to ensure that the prepared tundish dry material has excellent flexural strength and slag penetration resistance.

[0019] (2) The intermediate dry material of the present invention uses a compound of material A and material B. Material A plays a role in the continuity of the skeleton, and material B plays a role in the nano-blocking. A coarse skeleton layer is constructed with a particle size of 5-3 mm. Magnesia olivine (17%) and fused magnesium calcium sand (10%) form a high melting point hard skeleton, providing early compressive strength and CaO self-healing source. Hollow magnesia spinel spheres form a lightweight support, which also takes into account the primary heat insulation. The proportion of hollow magnesia spinel spheres is controlled to only 8%, so as not to weaken the compressive strength of coarse particles. The 3-1 mm particle size undertakes the secondary skeleton and macropore filling functions: Magnesia olivine (17%) and fused magnesium calcium sand (10%) continue to ensure the continuity of the skeleton; hollow magnesia spinel spheres (12%) serve as the main body of heat insulation, and their rough surface enhances particle interlocking and suppresses vibration segregation. The 1-0.074mm particle size serves as a micropore filler and lubricant. The magnesium olivine (14%) and fused magnesium calcium sand (7%) are homogeneous fillers with thermal expansion matching. The proportion of magnesium aluminum spinel hollow spheres is only 5%, which prevents the excessively fine hollow spheres from being crushed during vibration and losing their cavity structure, ensuring micro-insulation effect and avoiding pore blockage and weight increase.

[0020] (3) The intermediate dry material of the present invention uses a mixture of ammonium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silica powder as sintering agent. In the medium and low temperature range, ammonium dihydrogen phosphate and active magnesium oxide form a phosphate gel network that wraps around the surface of the aggregate, which can provide early strength and reduce the interparticle interface stress at high temperature through the "wrapping effect". In the medium temperature range, the prepared micron-sized glass powder fills the microcracks in liquid phase, enhances the interparticle bonding, and hinders the thermal shock propagation. Ammonium dihydrogen phosphate forms high viscosity Mg2P2O7 to ensure that the medium temperature strength does not decrease. In the high temperature range, silica powder fills the micropores. At the same time, silica powder and calcium oxide in magnesium calcium sand, alumina in micron-sized glass powder and magnesium oxide undergo in-situ high temperature sintering reaction to form dicalcium silicate-calcium hexaaluminate-calcium magnesium olivine composite ceramic skeleton, which improves the flexural strength, slag resistance and thermal shock resistance of the dry material.

[0021] (4) The tundish dry material of the present invention is further improved by adding a mixture of nano-titanium oxide and nano-zirconia. Nano-titanium oxide and calcium oxide form perovskite at high temperature. The plate-like grain boundaries block the micropores. Its plate-like crystal structure can penetrate between the micropores and physically block the slag liquid penetration path. Nano-zirconia reacts with calcium oxide to form zirconium oxide. This phase has a high melting point and high viscosity at high temperature. It can form a "high viscosity barrier" at the material-slag liquid interface, which chemically hinders the further penetration of slag liquid. Thus, there is a synergistic effect between nano-titanium oxide and nano-zirconia.

[0022] (5) The preparation method of the intermediate dry material of the present invention is simple, easy to realize industrial production, and the prepared intermediate dry material has stable performance. Detailed Implementation

[0023] Example 1 The intermediate ladle dry material described in Example 1 has the following raw material composition by mass percentage: Material A 64%, Material B 27.1%, Magnesium dihydrogen phosphate 3.9%, Active magnesium oxide 0.2%, Micron-sized glass powder 0.8%, Silica powder 3.1%, Nano titanium oxide 0.45%, and Nano zirconium oxide 0.45%. Material A, by mass percentage, consists of the following raw materials: Magnesia olivine 48%, Fused magnesium calcium sand 27%, and Magnesia aluminum spinel hollow spheres 25%. When distributed according to particle size, Magnesia olivine accounts for a significant portion of the raw materials with a particle size of 3mm ≤ particle size < 5mm. The raw materials are: 17% fused magnesia-calcium sand, 10% fused magnesia-calcium sand, and 8% hollow magnesia-alumina spinel spheres; for raw materials with a particle size of 1mm ≤ particle size < 3mm, 17% ferrolithite, 10% fused magnesia-calcium sand, and 12% hollow magnesia-alumina spinel spheres; for raw materials with a particle size of 0.074mm ≤ particle size ≤ 1mm, 14% ferrolithite, 7% fused magnesia-calcium sand, and 5% magnesia-alumina spinel spheres; the B material is a mixture of 53% ferrolithite, 25% fused magnesia-calcium sand, and 22% hollow magnesia-alumina spinel spheres by mass percentage, which is then ground and sieved to control the particle size of the mixture to ≤ 0.074mm.

[0024] in: The method for preparing the micron-sized glass powder is as follows: calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate are mixed and passed through a 60-mesh sieve. The mixture is then melted at 1350℃ for 30 minutes to obtain molten glass. The molten glass is poured into deionized water at 20℃ for water quenching, then dried at 120℃ for 2 hours and crushed. Finally, it is wet-milled to d50=10 microns and spray-dried to obtain micron-sized glass powder.

[0025] In the preparation process of the micron-sized glass powder, the mass ratio of calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate is 41.76 : 15.35 : 44.68 : 2.72 : 0.42 : 0.46.

[0026] The micron-sized glass powder has the following chemical composition by mass percentage: CaO 29.3%, B2O3 10.8%, SiO2 56.2%, Al2O3 2.1%, MgO 0.5%, P2O5 0.4%, Fe2O3 0.5%, Na2O 0.2%.

[0027] The wet ball milling process involves adding ethanol to the ball mill. The mass ratio of the crushed glass powder, ethanol, and zirconium balls is 1:1.1:4. The wet ball milling speed is 300 r / min, and the wet ball milling time is 3.5 h.

[0028] The spray drying process involves an inlet air temperature of 210°C, an outlet air temperature of 90°C, a feed rate of 12 mL / min, and a residence time of 12 s.

[0029] The preparation method of the intermediate bag dry material described in Example 1 consists of the following steps: (1) The magnesium olivine, fused magnesium calcium sand and magnesium aluminum spinel hollow spheres are batched according to the particle size of 3mm≤particle size<5mm, 1mm≤particle size<3mm and 0.074mm<particle size≤1mm, and then mixed to prepare material A; (2) By mass percentage, 53% of magnesium olivine, 25% of fused magnesium calcium sand and 22% of magnesium aluminum spinel hollow spheres are mixed, ground and sieved to control the particle size of the mixture to ≤0.074mm, and material B is prepared. (3) Mix magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder evenly, and then add nano titanium oxide and nano zirconium oxide to mix and prepare a mixture. (4) Mix A material, B material and the mixture to prepare the intermediate dry material.

[0030] The mixing time in step (1) is 11 min.

[0031] In step (3), magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder are mixed evenly for 6 minutes. Then, nano-titanium oxide and nano-zirconia are added and mixed for 6 minutes.

[0032] The mixing time in step (4) is 11 min.

[0033] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Example 1 at 110℃ was 12.7 MPa, and the flexural strength at 1400℃ was 9.6 MPa. According to GB / T 8931-2007, the static crucible erosion area percentage of the dry tundish material prepared in Example 1 at 1500℃ was 1.9%. According to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Example 1 at 1100℃ was 8.

[0034] Example 2 The intermediate dry material described in Example 2 has the following raw material composition by mass percentage: 65% A material, 26.0% B material, 3.8% magnesium dihydrogen phosphate, 0.2% activated magnesium oxide, 0.9% micron-sized glass powder, 3.2% silicon micropowder, 0.4% nano-titanium oxide, and 0.5% nano-zirconia. Material A, by mass percentage, consists of the following raw materials: 48% forsterite, 27% fused magnesia-calcium sand, and 25% hollow magnesium aluminum spinel spheres. When distributed according to particle size, forsterite accounts for 1% of the raw materials with a particle size of 3mm ≤ particle size < 5mm. 7%, fused magnesia-calcium sand accounts for 10%, and hollow magnesia-alumina spinel spheres account for 8%; in the raw materials with a particle size of 1mm ≤ particle size < 3mm, forsterite accounts for 17%, fused magnesia-calcium sand accounts for 10%, and hollow magnesia-alumina spinel spheres account for 12%; in the raw materials with a particle size of 0.074mm ≤ particle size ≤ 1mm, forsterite accounts for 14%, fused magnesia-calcium sand accounts for 7%, and magnesia-alumina spinel accounts for 5%; the B material is a mixture of 53% forsterite, 25% fused magnesia-calcium sand, and 22% hollow magnesia-alumina spinel spheres by mass percentage, which is then ground and sieved to control the particle size of the mixture to ≤ 0.074mm.

[0035] in: The method for preparing the micron-sized glass powder is as follows: calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate are mixed and passed through a 60-mesh sieve. The mixture is then melted at 1350℃ for 30 minutes to obtain molten glass. The molten glass is poured into deionized water at 20℃ for water quenching, then dried at 120℃ for 2 hours and crushed. Finally, it is wet-milled to d50=10 microns and spray-dried to obtain micron-sized glass powder.

[0036] In the preparation process of the micron-sized glass powder, the mass ratio of calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate is 41.76 : 15.35 : 44.68 : 2.72 : 0.42 : 0.46.

[0037] The micron-sized glass powder has the following chemical composition by mass percentage: CaO 29.3%, B2O3 10.8%, SiO2 56.2%, Al2O3 2.1%, MgO 0.5%, P2O5 0.4%, Fe2O3 0.5%, Na2O 0.2%.

[0038] The wet ball milling process involves adding ethanol to the ball mill. The mass ratio of the crushed glass powder, ethanol, and zirconium balls is 1:1.1:4. The wet ball milling speed is 300 r / min, and the wet ball milling time is 3.5 h.

[0039] The spray drying process involves an inlet air temperature of 210°C, an outlet air temperature of 90°C, a feed rate of 12 mL / min, and a residence time of 12 s.

[0040] The preparation method of the intermediate bag dry material described in Example 2 consists of the following steps: (1) The magnesium olivine, fused magnesium calcium sand and magnesium aluminum spinel hollow spheres are batched according to the particle size of 3mm≤particle size<5mm, 1mm≤particle size<3mm and 0.074mm<particle size≤1mm, and then mixed to prepare material A; (2) By mass percentage, 53% of magnesium olivine, 25% of fused magnesium calcium sand and 22% of magnesium aluminum spinel hollow spheres are mixed, ground and sieved to control the particle size of the mixture to ≤0.074mm, and material B is prepared. (3) Mix magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder evenly, and then add nano titanium oxide and nano zirconium oxide to mix and prepare a mixture. (4) Mix A material, B material and the mixture to prepare the intermediate dry material.

[0041] Wherein: the mixing time in step (1) is 12 min.

[0042] In step (3), magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder are mixed evenly for 7 minutes. Then, nano-titanium oxide and nano-zirconia are added and mixed for 7 minutes.

[0043] The mixing time in step (4) is 10 min.

[0044] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Example 2 at 110℃ was 13.0 MPa, and the flexural strength at 1400℃ was 10.1 MPa. According to GB / T 8931-2007, the percentage of static crucible erosion area of ​​the dry tundish material prepared in Example 2 at 1500℃ was 1.8%. According to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Example 2 at 1100℃ was 8.

[0045] Example 3 The intermediate dry material described in Example 3 has the following raw material composition by mass percentage: Material A 63%, Material B 28.2%, Magnesium dihydrogen phosphate 4.0%, Active magnesium oxide 0.2%, Micron-sized glass powder 0.7%, Silica powder 3.0%, Nano titanium oxide 0.5%, and Nano zirconium oxide 0.4%. Material A, by mass percentage, consists of the following raw materials: Magnesia olivine 48%, Fused magnesium calcium sand 27%, and Magnesia aluminum spinel hollow spheres 25%. When distributed according to particle size, Magnesia olivine accounts for 1% of the raw materials with a particle size of 3mm ≤ particle size < 5mm. 7%, fused magnesia-calcium sand accounts for 10%, and hollow magnesia-alumina spinel spheres account for 8%; in the raw materials with a particle size of 1mm ≤ particle size < 3mm, forsterite accounts for 17%, fused magnesia-calcium sand accounts for 10%, and hollow magnesia-alumina spinel spheres account for 12%; in the raw materials with a particle size of 0.074mm ≤ particle size ≤ 1mm, forsterite accounts for 14%, fused magnesia-calcium sand accounts for 7%, and magnesia-alumina spinel accounts for 5%; the B material is a mixture of 53% forsterite, 25% fused magnesia-calcium sand, and 22% hollow magnesia-alumina spinel spheres by mass percentage, which is then ground and sieved to control the particle size of the mixture to ≤ 0.074mm.

[0046] in: The method for preparing the micron-sized glass powder is as follows: calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate are mixed and passed through a 60-mesh sieve. The mixture is then melted at 1350℃ for 30 minutes to obtain molten glass. The molten glass is poured into deionized water at 20℃ for water quenching, then dried at 120℃ for 2 hours and crushed. Finally, it is wet-milled to d50=10 microns and spray-dried to obtain micron-sized glass powder.

[0047] In the preparation process of the micron-sized glass powder, the mass ratio of calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate is 41.76 : 15.35 : 44.68 : 2.72 : 0.42 : 0.46.

[0048] The micron-sized glass powder has the following chemical composition by mass percentage: CaO 29.3%, B2O3 10.8%, SiO2 56.2%, Al2O3 2.1%, MgO 0.5%, P2O5 0.4%, Fe2O3 0.5%, Na2O 0.2%.

[0049] The wet ball milling process involves adding ethanol to the ball mill. The mass ratio of the crushed glass powder, ethanol, and zirconium balls is 1:1.1:4. The wet ball milling speed is 300 r / min, and the wet ball milling time is 3.5 h.

[0050] The spray drying process involves an inlet air temperature of 210°C, an outlet air temperature of 90°C, a feed rate of 12 mL / min, and a residence time of 12 s.

[0051] The preparation method of the intermediate bag dry material described in Example 3 consists of the following steps: (1) The magnesium olivine, fused magnesium calcium sand and magnesium aluminum spinel hollow spheres are batched according to the particle size of 3mm≤particle size<5mm, 1mm≤particle size<3mm and 0.074mm<particle size≤1mm, and then mixed to prepare material A; (2) By mass percentage, 53% of magnesium olivine, 25% of fused magnesium calcium sand and 22% of magnesium aluminum spinel hollow spheres are mixed, ground and sieved to control the particle size of the mixture to ≤0.074mm, and material B is prepared. (3) Mix magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder evenly, and then add nano titanium oxide and nano zirconium oxide to mix and prepare a mixture. (4) Mix A material, B material and the mixture to prepare the intermediate dry material.

[0052] Wherein: the mixing time in step (1) is 10 min.

[0053] In step (3), magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder are mixed evenly for 5 minutes, and then nano-titanium oxide and nano-zirconia are added and mixed for 5 minutes.

[0054] The mixing time in step (4) is 12 min.

[0055] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Example 3 at 110℃ was 12.5 MPa, and the flexural strength at 1400℃ was 9.3 MPa. According to GB / T 8931-2007, the percentage of static crucible erosion area of ​​the dry tundish material prepared in Example 3 at 1500℃ was 2.0%. According to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Example 3 at 1100℃ was 8.

[0056] Comparative Example 1 The preparation method of the tundish dry material described in Comparative Example 1 is the same as that in Example 1, the only difference being the raw material composition. The tundish dry material described in Comparative Example 1, by mass percentage, has the following raw material composition: 68.1% A material, 27.1% B material, 0.8% micron-sized glass powder, 3.1% silicon micropowder, 0.45% nano-titanium oxide, and 0.45% nano-zirconia; wherein A material, B material, and micron-sized glass powder are the same as in Example 1.

[0057] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Comparative Example 1 at 110℃ was 8.1 MPa, and the flexural strength at 1400℃ was 6.5 MPa. According to GB / T 8931-2007, the percentage of static crucible erosion area of ​​the dry tundish material prepared in Comparative Example 1 at 1500℃ was 4.2%. According to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Comparative Example 1 at 1100℃ was 5.

[0058] Comparative Example 2 The preparation method of the tundish dry material described in Comparative Example 2 is the same as that in Example 1, the only difference being the raw material composition. The tundish dry material described in Comparative Example 2, by mass percentage, has the following raw material composition: A material 64.8%, B material 27.1%, magnesium dihydrogen phosphate 3.9%, activated magnesium oxide 0.2%, silicon micropowder 3.1%, nano titanium oxide 0.45%, and nano zirconium oxide 0.45%; wherein materials A and B are the same as in Example 1.

[0059] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Comparative Example 2 at 110℃ was 9.8 MPa; the flexural strength at 1400℃ was 7.2 MPa; according to GB / T 8931-2007, the percentage of static crucible erosion area of ​​the dry tundish material prepared in Comparative Example 2 at 1500℃ was 2.9%; and according to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Comparative Example 2 at 1100℃ was 6.

[0060] Comparative Example 3 The preparation method of the tundish dry material described in Comparative Example 3 is the same as that in Example 1, the only difference being the raw material composition. The tundish dry material described in Comparative Example 3, by mass percentage, has the following raw material composition: 67.1% A material, 27.1% B material, 3.9% magnesium dihydrogen phosphate, 0.2% activated magnesium oxide, 0.8% micron-sized glass powder, 0.45% nano-titanium oxide, and 0.45% nano-zirconia; wherein materials A, B material, and micron-sized glass powder are the same as in Example 1.

[0061] According to GB / T 3001-2017, the flexural strength of the dry tundish material prepared in Comparative Example 3 at 110℃ was 10.5 MPa, and the flexural strength at 1400℃ was 7.0 MPa. According to GB / T 8931-2007, the percentage of static crucible erosion area of ​​the dry tundish material prepared in Comparative Example 3 at 1500℃ was 2.6%. According to GB / T 30873-2014, the number of water-cooled thermal shock cycles of the dry tundish material prepared in Comparative Example 3 at 1100℃ was 6.

[0062] The comparison shows that the performance of the intermediate bag dry materials prepared in Examples 1-3 is better than that of Comparative Examples 1-3. The performance of the intermediate bag dry materials prepared in Comparative Examples 1-3 is greatly reduced due to the lack of any component in the sintering agent, such as magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder, or silicon micro powder.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A dry-type intermediate batch material, characterized in that: The raw material composition, by mass percentage, is as follows: Material A 63-65%, Material B 26.0-28.2%, Magnesium dihydrogen phosphate 3.8-4.0%, Active magnesium oxide 0.2%, Micron-sized glass powder 0.7-0.9%, Silica powder 3.0-3.2%, Nano titanium dioxide 0.4-0.5%, Nano zirconium oxide 0.4-0.5%; Material A, by mass percentage, consists of the following raw materials: Magnesia olivine 48%, Fused magnesium calcium sand 27%, and Magnesia aluminum spinel hollow spheres 25%, wherein, when distributed according to particle size, the raw materials with a particle size of 3mm ≤ particle size < 5mm... The raw material comprises 17% magnesia olivine, 10% fused magnesia-calcium sand, and 8% hollow magnesia-alumina spinel spheres; for raw materials with a particle size of 1mm ≤ particle size < 3mm, the raw material comprises 17% magnesia olivine, 10% fused magnesia-calcium sand, and 12% hollow magnesia-alumina spinel spheres; for raw materials with a particle size of 0.074mm ≤ particle size ≤ 1mm, the raw material comprises 14% magnesia olivine, 7% fused magnesia-calcium sand, and 5% magnesia-alumina spinel spheres; the B material is a mixture of 53% magnesia olivine, 25% fused magnesia-calcium sand, and 22% hollow magnesia-alumina spinel spheres by mass percentage, which is then ground and sieved to control the particle size of the mixture to ≤ 0.074mm.

2. The tundish dry material according to claim 1, characterized in that: The method for preparing the micron-sized glass powder is as follows: calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate are mixed and passed through a 60-mesh sieve. The mixture is then melted at 1350℃ for 30 minutes to obtain molten glass. The molten glass is poured into deionized water at 20℃ for water quenching, then dried at 120℃ for 2 hours and crushed. Finally, it is wet-milled to d50=10 microns and spray-dried to obtain micron-sized glass powder.

3. The tundish dry material according to claim 2, characterized in that: In the preparation process of the micron-sized glass powder, the mass ratio of calcium carbonate, boric acid, quartz sand, aluminum hydroxide, magnesium oxide, and ammonium dihydrogen phosphate is 41.76 : 15.35 : 44.68 : 2.72 : 0.42 : 0.

46.

4. The tundish dry material according to claim 2, characterized in that: The micron-sized glass powder has the following chemical composition by mass percentage: CaO 29.3%, B2O3 10.8%, SiO2 56.2%, Al2O3 2.1%, MgO 0.5%, P2O5 0.4%, Fe2O3 0.5%, Na2O 0.2%.

5. The tundish dry material according to claim 2, characterized in that: The wet ball milling process involves adding ethanol to the ball mill. The mass ratio of the crushed glass powder, ethanol, and zirconium balls is 1:1.1:

4. The wet ball milling speed is 300 r / min, and the wet ball milling time is 3.5 h.

6. The tundish dry material according to claim 2, characterized in that: The spray drying process involves an inlet air temperature of 210°C, an outlet air temperature of 90°C, a feed rate of 12 mL / min, and a residence time of 12 s.

7. A method for preparing the intermediate package dry material according to claim 1, characterized in that: It consists of the following steps: (1) The magnesium olivine, fused magnesium calcium sand and magnesium aluminum spinel hollow spheres are batched according to the particle size of 3mm≤particle size<5mm, 1mm≤particle size<3mm and 0.074mm<particle size≤1mm, and then mixed to prepare material A; (2) By mass percentage, 53% of magnesium olivine, 25% of fused magnesium calcium sand and 22% of magnesium aluminum spinel hollow spheres are mixed, ground and sieved to control the particle size of the mixture to ≤0.074mm, and material B is prepared. (3) Mix magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder evenly, and then add nano titanium oxide and nano zirconium oxide to mix and prepare a mixture. (4) Mix A material, B material and the mixture to prepare the intermediate dry material.

8. The method for preparing the intermediate batch dry feed according to claim 7, characterized in that: The mixing time in step (1) is 10-12 min.

9. The method for preparing the intermediate batch dry feed according to claim 7, characterized in that: In step (3), magnesium dihydrogen phosphate, active magnesium oxide, micron-sized glass powder and silicon powder are mixed evenly for 5-7 minutes. Then, nano-titanium oxide and nano-zirconia are added and mixed for 5-7 minutes.

10. The method for preparing the intermediate batch dry feed according to claim 7, characterized in that: The mixing time in step (4) is 10-12 min.