A high-temperature resistant steel ladle castable and its preparation method

Abstract

This invention relates to the field of castable technology, and proposes a high-temperature resistant ladle castable and its preparation method. The high-temperature resistant ladle castable comprises the following components by weight: 60-80 parts high-alumina bauxite, 2-5 parts magnesia, 10-15 parts magnesia-alumina spinel, 4-8 parts alumina, 2-5 parts fused magnesia, 1-5 parts calcium aluminate cement, 0.5-1.5 parts silica fume, 0.2-0.5 parts water-reducing agent, 8-15 parts silicon carbide whiskers, 2-4 parts dispersant, 1-2 parts zirconium oxide, and 0.5-1.7 parts neodymium oxide. This technical solution solves the problem in existing technologies where the incorporation of magnesia-alumina spinel leads to a decrease in the slag erosion resistance of the castable.

Description

Technical Field

[0001] This invention relates to the field of castable technology, specifically to a high-temperature resistant steel ladle castable and its preparation method. Background Technology

[0002] As the cornerstone of national industrialization, the steel industry occupies a core position in the national economy. In the ironmaking and steelmaking processes, the steel ladle, as a crucial container holding molten steel at high temperatures, directly impacts production safety and efficiency due to the performance of its lining material. Compared to traditional shaped refractories, ladle castables stand out with significant advantages such as simplified production processes, controllable manufacturing costs, and excellent construction fluidity. These unshaped refractories can be cast on-site according to the complex structure of the ladle, effectively eliminating defects in brick joints, significantly reducing the risk of molten steel leakage, and significantly improving safety and structural integrity.

[0003] However, the high-temperature service environment poses severe challenges to ladle castables, with weak thermal shock resistance being a major technical bottleneck restricting their application. Currently, magnesium aluminate spinel is often added to refractory materials to improve the thermal shock resistance of castables. However, the addition of magnesium aluminate spinel reduces the material's resistance to slag erosion, severely affecting the service life of the ladle. Therefore, there is a need to develop a high-temperature resistant ladle castable with good thermal shock resistance and slag erosion resistance. Summary of the Invention

[0004] This invention proposes a high-temperature resistant ladle castable and its preparation method, which solves the problem that the inclusion of magnesium aluminum spinel in the existing technology leads to a decrease in the slag erosion resistance of the castable.

[0005] The technical solution of the present invention is as follows:

[0006] This invention proposes a high-temperature resistant steel ladle castable, comprising the following components by weight: 60-80 parts high-alumina bauxite, 2-5 parts magnesia, 10-15 parts magnesium aluminum spinel, 4-8 parts alumina, 2-5 parts fused magnesia, 1-5 parts calcium aluminate cement, 0.5-1.5 parts silica fume, 0.2-0.5 parts water-reducing agent, 8-15 parts silicon carbide whiskers, 2-4 parts dispersant, 1-2 parts zirconium oxide, and 0.5-1.7 parts neodymium oxide.

[0007] As a further technical solution, the dispersant is composed of sodium oleate and alkyl glycoside, wherein the alkyl glycoside is composed of alkyl glycoside APG0810 and alkyl glycoside APG1214.

[0008] Sodium oleate, an inorganic electrolyte dispersant, adsorbs onto the surface of silicon carbide whiskers, significantly increasing the absolute value of the whisker surface potential. This generates an electrostatic repulsion effect within the electric double layer, resulting in a stable dispersion of the whiskers. Alkyl glycosides, nonionic dispersants, adsorb onto the surface of silicon carbide whiskers, forming an adsorption layer of a certain thickness. The steric hindrance repulsion effect achieves dispersion. Alkyl glycosides APG0810 and APG1214, when combined, can enhance dispersibility through complementary molecular structures. APG0810 is highly hydrophilic and diffuses rapidly, while APG1214 is hydrophobic and readily adsorbs particles. The two alkyl glycosides synergistically improve the dispersibility of silicon carbide whiskers and other powders in the castable, thereby enhancing the thermal shock resistance of the castable.

[0009] As a further technical solution, the mass ratio of sodium oleate to alkyl glycoside is 3:5.

[0010] As a further technical solution, the mass ratio of the alkyl glycoside APG0810 to the alkyl glycoside APG1214 is 1:1~5.

[0011] In this invention, when the content of alkyl glycoside APG1214 in the ladle castable is too high, the solubility of the composite alkyl glycoside composed of alkyl glycosides APG0810 and APG1214 decreases, making it prone to self-polymerization and reducing the adsorption rate on the silicon carbide surface, thereby reducing the dispersion effect. When the content of alkyl glycoside APG1214 is too low, the steric hindrance effect of the composite alkyl glycoside composed of alkyl glycosides APG0810 and APG1214 is weak when adsorbed on the particle surface, resulting in poor dispersion stability. When the mass ratio of APG0810 to APG1214 is 1:1 to 5, it can exhibit better dispersibility, thereby further improving the thermal shock resistance of the ladle castable.

[0012] As a further technical solution, the mass ratio of alkyl glycoside APG0810 to alkyl glycoside APG1214 is 1:3. When the mass ratio of alkyl glycoside APG0810 to alkyl glycoside APG1214 is 1:3, a stronger dispersion effect can be exhibited, thereby further improving the thermal shock resistance of the ladle castable.

[0013] As a further technical solution, the alumina content in the calcium aluminate cement is 73.5wt%~75.5wt%. When calcium aluminate cement with an alumina content of 73.5wt%~75.5wt% is used as a castable, it exhibits high refractoriness, good high-temperature strength retention, excellent thermal shock resistance, strong resistance to alkaline slag erosion, and superior sintering volume stability, making it suitable for harsh high-temperature conditions.

[0014] As a further technical solution, the water-reducing agent is a lignin sulfonate water-reducing agent, which includes one or more of sodium lignin sulfonate, calcium lignin sulfonate, and magnesium lignin sulfonate. When used in castables, lignin sulfonate water-reducing agents can reduce water consumption, improve fluidity, and enhance workability; they can also delay setting time, facilitating operation; and they can lower the water-cement ratio, increasing structural density, thereby improving the strength and erosion resistance of the castable, while also being relatively low in cost.

[0015] As a further technical solution, the alumina micro powder has a particle size of 2~3μm. When alumina micro powder with a particle size of 2~3μm is used in ladle castables, it can fill the gaps between particles, reduce porosity, and increase density and strength; improve matrix fluidity and enhance construction performance; promote sintering at high temperatures, and improve the thermal shock resistance and slag erosion resistance of ladle castables. Moreover, the moderate particle size balances filling effect and cost advantages.

[0016] As a further technical solution, the silicon carbide whiskers have a diameter of 100~500nm and a length of 10~50μm. Adding silicon carbide whiskers to ladle castables can form a bridging and toughening network through a nanoscale one-dimensional structure, significantly improving the thermal shock resistance of the ladle castables through crack deflection, pinning, and pull-out mechanisms. Its high thermal conductivity reduces thermal stress concentration, its chemical stability enhances resistance to slag erosion, and it also improves the material's wear resistance and structural toughness, thereby enhancing the ladle castables' resistance to slag erosion, wear resistance, and toughness.

[0017] This invention also proposes a method for preparing a high-temperature resistant steel ladle castable, comprising the following steps:

[0018] S1. After the components of the high-temperature resistant steel ladle castable are mixed evenly, a mixture is obtained;

[0019] S2. After mixing the mixture and water evenly, put it into the mold, vibrate to form, demold and dry to obtain high temperature resistant steel ladle casting material.

[0020] As a further technical solution, the mass ratio of the mixture to water is 1:10.

[0021] The working principle and beneficial effects of this invention are as follows:

[0022] This invention relates to a high-temperature resistant ladle castable prepared from high-alumina bauxite, magnesia, magnesium aluminum spinel, alumina micro powder, fused magnesia, calcium aluminate cement, silica micro powder, water-reducing agent, silicon carbide whiskers, dispersant, zirconium oxide, and neodymium oxide. This high-temperature resistant castable exhibits strong thermal shock resistance and slag erosion resistance. The reasons are as follows: Firstly, the addition of zirconium oxide to the ladle castable can achieve a phase transformation toughening effect, absorbing crack propagation energy and inhibiting the propagation of erosive cracks, thereby improving the erosion resistance of the ladle castable. Secondly, the simultaneous addition of magnesium aluminum spinel, zirconium oxide, and neodymium oxide can sinter neodymium zirconate at high temperatures. As a second phase added to the castable, it can play a heterogeneous nucleation role during sintering, increasing nucleation sites, promoting matrix grain refinement, thereby reducing the difference in thermal expansion within individual grains and reducing stress concentration. Simultaneously, it increases the number of grain boundaries, hindering crack propagation and dispersing stress, thus improving the thermal shock resistance of the castable. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, the following materials were used: high-alumina bauxite (particle size 74 μm, alumina content 88%), magnesia (particle size 3-5 mm), magnesium aluminum spinel (particle size 0.6-0.12 mm), alumina (particle size 3 μm, purity 99.6%), fused magnesia (particle size 74 μm), calcium aluminate cement CA75 (purchased from Zhengzhou Jinghua Special Cement Co., Ltd.), silica fume (particle size 44 μm, purity 97%), silicon carbide whiskers (diameter 100-500 nm, length 10-50 μm), zirconium oxide (particle size 1 μm, purity 99.9%), and neodymium oxide (particle size 40 nm, purity 99.9%).

[0025] Example 1

[0026] A high-temperature resistant steel ladle castable comprises the following components by weight: 60 parts high-alumina bauxite, 2 parts magnesia, 10 parts magnesium aluminum spinel, 4 parts alumina, 2 parts fused magnesia, 1 part calcium aluminate cement, 0.5 parts silica fume, 0.2 parts sodium lignosulfonate, 8 parts silicon carbide whiskers, 2 parts dispersant, 1 part zirconium oxide, and 0.5 parts neodymium oxide, wherein the dispersant is sodium oleate;

[0027] A method for preparing a high-temperature resistant steel ladle castable includes the following steps:

[0028] S1. After the components of the high-temperature resistant steel ladle castable are mixed evenly, a mixture is obtained;

[0029] S2. After mixing the mixture and water evenly, put it into the mold, vibrate to form, demold and dry to obtain high temperature resistant steel ladle casting material; wherein the mass ratio of water to mixture is 1:10.

[0030] Example 2

[0031] Compared with Example 1, the only difference in Example 2 is that the high-temperature resistant steel ladle castable in this example includes the following components by weight: 70 parts high-alumina bauxite, 4 parts magnesia, 12 parts magnesium aluminum spinel, 6 parts alumina, 4 parts fused magnesia, 3 parts calcium aluminate cement, 1 part silica fume, 0.4 parts calcium lignosulfonate, 10 parts silicon carbide whiskers, 3 parts dispersant, 1.5 parts zirconium oxide, and 1.3 parts neodymium oxide, wherein the dispersant is sodium oleate.

[0032] Example 3

[0033] Compared with Example 1, the only difference in Example 3 is that the high-temperature resistant steel ladle castable in this example includes the following components by weight: 80 parts high-alumina bauxite, 5 parts magnesia, 15 parts magnesium aluminum spinel, 8 parts alumina, 5 parts fused magnesia, 5 parts calcium aluminate cement, 1.5 parts silica fume, 0.5 parts magnesium lignosulfonate, 15 parts silicon carbide whiskers, 4 parts dispersant, 2 parts zirconium oxide, and 1.7 parts neodymium oxide, wherein the dispersant is sodium oleate.

[0034] Example 4

[0035] Compared with Example 2, the only difference in Example 4 is that the dispersant in this example is composed of sodium oleate and alkyl glycoside in a mass ratio of 3:5, and the alkyl glycoside is composed of alkyl glycoside APG0810 and alkyl glycoside APG1214 in a mass ratio of 1:1.

[0036] Example 5

[0037] Compared with Example 2, the only difference in Example 5 is that the dispersant in this example is composed of sodium oleate and alkyl glycoside in a mass ratio of 3:5, and the alkyl glycoside is composed of alkyl glycoside APG0810 and alkyl glycoside APG1214 in a mass ratio of 1:3.

[0038] Example 6

[0039] Compared with Example 2, the only difference in Example 6 is that the dispersant in this example consists of sodium oleate and alkyl glycoside in a mass ratio of 3:5, and the alkyl glycoside consists of alkyl glycoside APG0810 and alkyl glycoside APG1214 in a mass ratio of 1:5.

[0040] Example 7

[0041] Compared with Example 2, the only difference in Example 7 is that the dispersant in this example is only an alkyl glycoside, wherein the alkyl glycoside is composed of alkyl glycoside APG0810 and alkyl glycoside APG1214 in a mass ratio of 1:3.

[0042] Comparative Example 1

[0043] The only difference between this comparative example and Example 1 is that zirconium oxide is replaced with an equal amount of neodymium oxide in this comparative example.

[0044] Comparative Example 2

[0045] The only difference between this comparative example and Example 1 is that neodymium oxide is replaced with an equal amount of zirconium oxide in this comparative example.

[0046] Comparative Example 3

[0047] The only difference between this comparative example and Example 1 is that zirconium oxide and neodymium oxide were not added in this comparative example.

[0048] Comparative Example 4

[0049] The only difference between this comparative example and Example 1 is that neodymium oxide is replaced with an equal amount of lanthanum oxide (particle size 40 nm, purity 99.9%).

[0050] The ladle castables prepared in Examples 1-7 and Comparative Examples 1-4 were tested according to the following method:

[0051] 1. Thermal shock resistance: The thermal shock resistance of the samples was tested according to Method 1: Water quenching method for straight brick samples, as specified in GB / T 30873-2014 "Test Method for Thermal Shock Resistance of Refractory Materials".

[0052] 2. Slag erosion resistance: The slag erosion rate of the sample is tested by slag immersion and aeration method as specified in GB / T8931-2007 "Test Method for Slag Resistance of Refractory Materials";

[0053] The measurement results are shown in Tables 1 and 2.

[0054] Table 1. Performance test results of ladle castables in Examples 1-3 and Comparative Examples 1-4

[0055]

[0056] Table 2. Performance test results of ladle castables in Examples 2, 4-7

[0057]

[0058] As shown in Tables 1-2, the high-temperature resistant ladle castable prepared by this invention exhibits high thermal shock resistance and good slag erosion resistance. A comparison of Example 1 with Comparative Examples 1-4 demonstrates that the addition of zirconium oxide and neodymium oxide significantly improves the thermal shock resistance and slag erosion resistance of the ladle castable. A comparison of Example 2 with Examples 4-7 shows that when the alkyl glycosides are composed of alkyl glycosides APG0810 and APG1214 in a mass ratio of 1:3, the thermal shock resistance of the ladle castable can be further enhanced.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high temperature resistant ladle casting material, characterized by, The composition comprises the following components by weight: high bauxite 60-80 parts, magnesia 2-5 parts, magnesium aluminate spinel 10-15 parts, alumina 4-8 parts, fused magnesia 2-5 parts, calcium aluminate cement 1-5 parts, silica fume 0.5-1.5 parts, water reducing agent 0.2-0.5 parts, silicon carbide whisker 8-15 parts, dispersant 2-4 parts, zirconia 1-2 parts, neodymium oxide 0.5-1.7 parts. The dispersant is composed of sodium oleate and alkyl glycoside, and the alkyl glycoside is composed of alkyl glycoside APG0810 and alkyl glycoside APG1214.

2. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The mass ratio of sodium oleate and alkyl glycoside is 3:5-6.

3. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The mass ratio of alkyl glycoside APG0810 and alkyl glycoside APG1214 is 1:1-5.

4. A high temperature resistant steel ladle castable according to claim 3, characterized in that, The mass ratio of alkyl glycoside APG0810 and alkyl glycoside APG1214 is 1:

3.

5. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The content of alumina in the calcium aluminate cement is 73.5wt%-75.5wt%.

6. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The water reducing agent is a lignosulfonate water reducing agent, and the lignosulfonate water reducing agent includes one or more of sodium lignosulfonate, calcium lignosulfonate and magnesium lignosulfonate.

7. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The particle size of the alumina is 2-3μm.

8. A high temperature resistant steel ladle castable according to claim 1, characterized in that, The diameter of the silicon carbide whisker is 100-500nm, and the length is 10-50μm.

9. A method for producing a high temperature resistant ladle castable for producing the high temperature resistant ladle castable according to any one of claims 1 to 8, characterized by, The method comprises the following steps: S1, uniformly mixing the components of the high-temperature-resistant ladle castable to obtain a mixture; S2, uniformly mixing the mixture and water, placing them in a mold, vibration forming, demolding and drying to obtain the high-temperature-resistant ladle castable.

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