A quartz-based refractory casting material for steel ladles and its preparation process

Abstract

This invention provides a quartz-based refractory castable material for steel ladles and its preparation process, belonging to the field of refractory materials technology. The process includes the following steps: S1, preparing composite aggregate; S2, preparing modified fused silica fiber; S3, mixing pre-fired quartz, composite aggregate, alumina micropowder, silica micropowder, modified fused silica fiber, aluminum hexametaphosphate, additives, and deionized water to obtain the quartz-based refractory castable material for steel ladles. This invention can improve the overall material strength while exhibiting good resistance to slag erosion.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a quartz-based steel ladle refractory casting material and its preparation process. Background Technology

[0002] The ladle is an indispensable smelting vessel in the iron and steel metallurgical production process. Its main tasks include bearing high-temperature molten steel, completing deoxidation and alloying reactions, providing intermediate buffering for the molten steel, and providing a stable transition between converters, electric furnaces, and continuous casting. During service, the ladle is typically exposed to high-temperature environments above 1300℃, simultaneously enduring multiple coupled effects such as severe temperature fluctuations, slag erosion, molten steel scouring, and mechanical vibration. Therefore, the performance of the ladle's refractory casting materials directly determines the ladle's service life, the purity of the molten steel, energy consumption levels, and the safety and stability of the entire steelmaking process. With the modern steelmaking industry developing towards longer service life, lower consumption, and higher efficiency, higher requirements are being placed on the comprehensive performance of ladle refractory materials.

[0003] Among the various refractory material systems for steel ladles, quartz-based refractory castables have gradually gained attention due to their abundant raw material resources, low coefficient of thermal expansion, good refractory and heat insulation properties, and convenient construction, especially showing certain application potential under certain acidic or neutral slag conditions. However, due to the extremely harsh service environment of steel ladles, traditional quartz-based castables still exhibit significant shortcomings under high-temperature conditions, falling far short of meeting the requirements for long service life and high stability operation of steel ladles.

[0004] First, quartz (SiO2) undergoes multiple crystal transformations at high temperatures, accompanied by significant volume changes. This easily leads to thermal stress concentration within the material, causing microcrack initiation and propagation, thus weakening the overall strength and reducing thermal shock stability. Second, quartz gradually softens above approximately 1200℃, forming a low-viscosity glassy phase. Its viscous flow behavior causes creep and deformation under the hydrostatic pressure and thermal load of molten steel, leading to lining sinking, local instability, and even spalling, severely impacting ladle safety. Furthermore, quartz-based refractories are highly sensitive to the chemical corrosion of steel slag. Common alkaline slag systems in ladles, such as CaO-FeO-MnO, react with SiO2 to form low-melting-point calcium silicates, deepening the erosion layer of the final quartz-based refractories and accelerating material loss, failing to meet the requirements for medium- to long-life ladles.

[0005] Therefore, there is a need to provide a quartz-based refractory casting material for steel ladles and its preparation process to solve the problems existing in the prior art. Summary of the Invention

[0006] In view of this, the present invention provides a quartz-based refractory casting material for steel ladles and its preparation process, which can improve the overall material strength while having good resistance to slag erosion.

[0007] To achieve the above objectives, the present invention provides a preparation process for a quartz-based refractory castable material for steel ladles, comprising the following steps:

[0008] S1. Alumina colloidal sol and high-purity quartz sand are mixed and stirred, allowed to stand, separated, dried and sintered at high temperature to obtain composite aggregate.

[0009] S2. Mix ZrOCl2·8H2O, Y(NO3)3·6H2O, deionized water and anhydrous ethanol, add citric acid solution and ethylene glycol, stir at high temperature, cool, add pretreated fused silica fiber and stir magnetically, remove the fiber, let stand, dry, heat treat, cool, and obtain modified fused silica fiber.

[0010] S3. Mix pre-fired quartz stone, composite aggregate, alumina powder, silica powder, modified fused silica fiber, aluminum hexametaphosphate, additives, and deionized water to obtain quartz stone-based steel ladle refractory casting material.

[0011] This invention introduces a novel preparation process. First, an alumina nanoparticle coating is applied to the surface of quartz sand, followed by high-temperature sintering and solidification to form a core-shell structured composite aggregate. The alumina shell, acting as a refractory secondary phase, provides rigid constraint at high temperatures, inhibiting softening and the formation of a low-viscosity glassy phase, which further leads to viscous flow and improves high-temperature creep resistance. Simultaneously, the alumina shell suppresses abrupt volume changes and stress concentrations caused by quartz crystal transformation. Furthermore, during high-temperature sintering and solidification, SiO2 and Al2O3 partially react at the interface to form mullite. This mullite layer further pins the interface and inhibits particle migration, thereby enhancing the overall high-temperature stability and thermal shock resistance. At the same time, the alumina shell and the interfacial mullite exhibit excellent chemical inertness relative to alkaline steel slag, effectively blocking slag erosion and the penetration of active SiO2 cores, thus improving the overall material's resistance to slag erosion.

[0012] This invention utilizes a sol-gel method to uniformly complex and disperse Zr and Y elements, followed by high-temperature pyrolysis and crystallization to form a continuous and dense Y₂Zr₂O₇ ceramic coating on the surface of fused silica fibers. Y₂Zr₂O₇ is a defective fluorite structure with oxygen vacancies, possessing both high melting point, high strength, and excellent thermal stability, significantly improving the structural stability and mechanical retention of fused silica fibers under high-temperature conditions. Furthermore, the semi-weak interface structure between the Y₂Zr₂O₇ ceramic coating and the fibers effectively induces crack deflection, bifurcation, and passivation, delaying crack propagation and consuming more energy, thereby improving the flexural strength and thermal shock resistance of the casting material. Moreover, the high strength and low thermal expansion characteristics of fused silica fibers are further enhanced by Y₂Zr₂O₇ modification. The fused silica fibers form a uniformly distributed three-dimensional reinforcing network within the casting material, providing load-bearing and buffering effects on the matrix, thus improving the overall thermal shock resistance.

[0013] Meanwhile, Y2Zr2O7 itself is a stable phase with high chemical inertness to steel slag components, which significantly reduces the wettability and dissolution rate of steel slag on fibers. Therefore, modified fused silica fibers can not only act as a reinforcing phase in the matrix, but also form a uniformly distributed corrosion-resistant skeleton, effectively blocking the penetration path of molten slag and delaying the expansion of the erosion front into the depth of the material.

[0014] Optionally, the alumina colloidal sol is obtained by adding 40-50 parts by weight of nano-alumina to 150-200 parts by weight of deionized water, mixing and stirring for 5-10 minutes, and then ultrasonically treating for 10-15 minutes.

[0015] Optionally, in step S1, alumina colloidal sol and 80-90 parts by weight of high-purity quartz sand are stirred at room temperature for 4-6 hours, allowed to stand for 2 hours, then separated into solid and liquid, the precipitate is dried, and sintered at 1100-1300℃ for 2-3 hours to obtain composite aggregate.

[0016] Optionally, the pretreated fused silica fiber is obtained by immersing fused silica fiber in an aqueous ethanol solution with a volume concentration of 70%, ultrasonically treating it for 10-15 minutes, removing it, rinsing it with deionized water 1-3 times, and drying it in an oven at 80-100°C for 1-2 hours.

[0017] This pretreatment, through ultrasonic treatment with an ethanol-water solution, removes impurities and oil from the surface of fused silica fibers, increases their surface activity and roughness, and enhances the wettability and adhesion of the subsequent mixed sol on the fiber surface.

[0018] Optionally, in step S2, ZrOCl2·8H2O, Y(NO3)3·6H2O, deionized water and anhydrous ethanol are mixed and magnetically stirred at a rate of 200-300 rpm for 10-20 min. Citric acid solution is added dropwise, and the mixture is stirred continuously at 70°C for 30-50 min. Ethylene glycol is then added, and the mixture is heated to 85°C and stirred for 3-5 h. After cooling to room temperature, a mixed sol is obtained. Pretreated fused silica fibers are added, and the mixture is magnetically stirred at a rate of 200-300 rpm for 1-2 h at room temperature. The fibers are then removed, allowed to stand for 2-3 h, dried at 100-120°C for 2 h, and placed in a muffle furnace. The temperature is increased to 600°C at a rate of 2°C / min and held for 1 h. The temperature is then increased to 1350°C at a rate of 5°C / min and held for 2 h. After cooling to room temperature, modified fused silica fibers are obtained.

[0019] During the preparation process, the segmented heat treatment method can gradually decompose the precursors in the sol and form a stable Y2Zr2O7 phase. The low-temperature stage removes organic matter and residual solvents to prevent cracking on the surface of the fused silica fiber. The high-temperature stage promotes grain growth and coating densification, making the modified fused silica fiber structure more stable and the bonding stronger, further improving thermal shock resistance and corrosion resistance.

[0020] Optionally, the modified fused silica fiber comprises the following raw materials in parts by weight: 28-30 parts ZrOCl2·8H2O, 22-24 parts Y(NO3)3·6H2O, 100-120 parts deionized water, 40-50 parts anhydrous ethanol, 22-25 parts citric acid solution, 18-20 parts ethylene glycol, and 15-20 parts pretreated fused silica fiber; wherein the citric acid solution has a mass concentration of 7.8%.

[0021] Optionally, the pre-calcined quartz stone is prepared by coarsely crushing 70-80 parts by weight of natural quartz stone in a pulverizer, rinsing it 2-4 times with deionized water, drying it at 100-120℃ for 18-24 hours, placing it in a muffle furnace, heating it to 300-400℃ at a rate of 3℃ / min and holding it for 1-2 hours, then heating it to 1000-1100℃ at a rate of 5℃ / min and holding it for 2-3 hours, then heating it to 1250-1300℃ and holding it for 1-2 hours, and finally slowly cooling it to room temperature in the furnace.

[0022] This invention, through the pre-firing treatment of natural quartz, can effectively remove impurities and water of crystallization, eliminate internal residual stress, promote the transformation of quartz crystal form from α-quartz to a high-temperature stable phase, and improve the structural stability and thermal shock stability of quartz.

[0023] Optionally, in step S3, pre-fired quartz stone, composite aggregate, alumina micro powder, silica micro powder, modified fused silica fiber, and aluminum hexametaphosphate are placed into a mortar mixer and mixed for 2-5 minutes. Then, additives and deionized water are added and mixed for 5-10 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0024] Optionally, the additive is a tar-silica sol suspension, which is prepared by mixing 3-5 parts by weight of tar and 10 parts by weight of silica sol and stirring for 5 minutes, then adding 0.16 parts by weight of aluminum dihydrogen phosphate and stirring continuously for 5-10 minutes, followed by ultrasonic treatment for 10 minutes.

[0025] This invention utilizes tar as a carbon source and silica sol as a continuous dispersion medium. Aluminum dihydrogen phosphate improves the wetting and dispersion of tar in the silica sol system, thereby achieving uniform dispersion of the carbon source in the overall material and filling the pores. During subsequent high-temperature treatment and high-temperature service, SiC whiskers are formed in situ with the silicon source within the pores, resulting in uniform distribution of SiC whiskers within the system. This improves the overall mechanical strength while reducing the porosity of the overall material and inhibiting oxygen penetration.

[0026] The present invention also provides a quartz-based refractory casting material for steel ladles, comprising the following raw materials in parts by weight: 40-50 parts pre-fired quartz, 30-35 parts composite aggregate, 1-5 parts alumina micro powder, 4-8 parts silica micro powder, 10-15 parts modified fused silica fiber, 1.5-2 parts aluminum hexametaphosphate, 5-10 parts deionized water, and 13.16-15.16 parts additives.

[0027] The composition of this invention constructs a dense skeleton through a multi-level particle system of pre-fired quartz, composite aggregate, and silicon and alumina micro powder. Modified fused silica fiber enhances crack resistance and thermal shock resistance. Composite aggregate and modified fused silica fiber together improve the overall slag erosion resistance. Aluminum hexametaphosphate improves dispersibility and binding force. The synergistic effect of multiple components gives the material high strength, erosion resistance, and good high-temperature stability.

[0028] The above-described technical solution of the present invention has at least the following beneficial effects:

[0029] 1. This invention improves the overall high-temperature stability and crack resistance of composite aggregates by forming an alumina shell layer and an interfacial mullite layer on the surface of quartz sand. The alumina layer provides rigid constraints and suppresses abrupt volume changes and stress concentrations caused by quartz crystal transformation, while the mullite layer enhances interfacial bonding. Both layers are chemically inert to alkaline steel slag, further improving the material's resistance to slag erosion and high-temperature creep.

[0030] 2. This invention employs a sol-gel method to form a dense and uniform Y2Zr2O7 ceramic coating on the surface of fused silica fibers. Y2Zr2O7 possesses a high melting point, excellent thermal stability, and chemical inertness, significantly enhancing the structural stability and mechanical retention of the fibers at high temperatures. The semi-weak interface formed between the coating and the fibers effectively induces crack deflection, passivation, and energy dissipation, thereby enhancing the overall fracture toughness and thermal shock resistance of the material. Furthermore, the modified fused silica fibers form a three-dimensional reinforcing network within the matrix, acting as a load-bearing and buffering agent; simultaneously, the slag erosion resistance of Y2Zr2O7 constructs a stable and corrosion-resistant skeleton, blocking the penetration path of steel slag and significantly improving the overall erosion resistance and service life. Attached Figure Description

[0031] Figure 1 The above are high-temperature creep curves of Embodiment 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0033] Example 1

[0034] By mass, 50 parts of nano alumina were added to 180 parts of deionized water and mixed for 10 min. After ultrasonic treatment for 15 min, alumina colloidal sol was obtained. 85 parts of high-purity quartz sand were added and stirred at room temperature for 6 h. After standing for 2 h, solid-liquid separation was performed, the precipitate was dried, and sintered at 1250℃ for 3 h to obtain composite aggregate.

[0035] Thirty parts of fused silica fiber were immersed in 500 parts of a 70% (v / v) ethanol aqueous solution, sonicated for 15 min, removed, rinsed three times with deionized water, and dried in a 90℃ oven for 2 h to obtain pretreated fused silica fiber. Thirty parts of ZrOCl2·8H2O, 24 parts of Y(NO3)3·6H2O, 120 parts of deionized water, and 50 parts of anhydrous ethanol were mixed and magnetically stirred at 300 rpm for 20 min. Then, 25 parts of a 7.8% (w / w) citric acid solution were added dropwise, and the mixture was dried at 70℃. After stirring continuously for 50 min, 20 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 5 h. After cooling to room temperature, a mixed sol was obtained. 20 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 300 rpm for 2 h at room temperature. The fiber was then removed, allowed to stand for 3 h, dried at 120℃ for 2 h, and then placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 h. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 h. After cooling to room temperature, modified fused silica fiber was obtained.

[0036] A tar-silica sol suspension was prepared by mixing 3.5 parts of tar and 10 parts of silica sol for 5 minutes, then adding 0.16 parts of aluminum dihydrogen phosphate and stirring continuously for 10 minutes, followed by ultrasonic treatment for 15 minutes. 80 parts of natural quartz were coarsely crushed in a pulverizer, rinsed four times with deionized water, dried at 110℃ for 24 hours, and then placed in a muffle furnace. The temperature was increased to 300℃ at a rate of 3℃ / min and held for 2 hours, followed by further heating to 110℃ at a rate of 5℃ / min. Pre-fired quartz stone was obtained by holding the material at 0℃ for 3 hours, raising the temperature to 1250℃, holding it at 1250℃ for 2 hours, and then slowly cooling it to room temperature in the furnace. 40 parts of pre-fired quartz stone, 35 parts of composite aggregate, 3 parts of alumina micro powder, 5 parts of silica micro powder, 15 parts of modified fused silica fiber, and 2 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 5 minutes. Then, 13.46 parts of tar-silica sol suspension and 5 parts of deionized water were added and mixed for 10 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0037] Example 2

[0038] By weight, 40 parts of nano alumina were added to 150 parts of deionized water and mixed for 5 minutes. After ultrasonic treatment for 10 minutes, alumina colloidal sol was obtained. 80 parts of high-purity quartz sand were added and stirred at room temperature for 4 hours. After standing for 2 hours, solid-liquid separation was performed, the precipitate was dried, and sintered at 1100℃ for 2 hours to obtain composite aggregate.

[0039] Twenty parts of fused silica fiber were immersed in 500 parts of a 70% (v / v) ethanol aqueous solution, sonicated for 10 min, removed, rinsed once with deionized water, and dried in an oven at 80℃ for 1 h to obtain pretreated fused silica fiber. Twenty-eight parts of ZrOCl2·8H2O, 22 parts of Y(NO3)3·6H2O, 100 parts of deionized water, and 40 parts of anhydrous ethanol were mixed and magnetically stirred at 200 rpm for 10 min. Then, 22 parts of a 7.8% (w / w) citric acid solution were added dropwise, and the mixture was dried at 70℃. After stirring continuously for 30 minutes, 18 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 3 hours. After cooling to room temperature, a mixed sol was obtained. 15 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 200 rpm for 1 hour at room temperature. The fiber was then removed, allowed to stand for 2 hours, dried at 100℃ for 2 hours, and placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 hour. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 hours. After cooling to room temperature, modified fused silica fiber was obtained.

[0040] Three parts of tar and ten parts of silica sol were mixed and stirred for 5 minutes. Then, 0.16 parts of aluminum dihydrogen phosphate were added and stirred continuously for 5 minutes. The mixture was then sonicated for 10 minutes to obtain a tar-silica sol suspension. Seventy parts of natural quartz were coarsely crushed in a pulverizer, rinsed twice with deionized water, dried at 100°C for 18 hours, and then placed in a muffle furnace. The temperature was increased to 350°C at a rate of 3°C / min and held for 1 hour. Finally, the temperature was increased to 1000°C at a rate of 5°C / min. The material was kept at a constant temperature for 2 hours, then heated to 1250℃ and kept at that temperature for 1 hour. It was then slowly cooled to room temperature in the furnace to obtain pre-fired quartz stone. 45 parts of pre-fired quartz stone, 30 parts of composite aggregate, 1 part of alumina micro powder, 4 parts of silica micro powder, 10 parts of modified fused silica fiber, and 1.5 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 2 minutes. Then, 13.16 parts of tar-silica sol suspension and 7 parts of deionized water were added and mixed for 5 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0041] Example 3

[0042] By mass, 48 ​​parts of nano alumina were added to 200 parts of deionized water, mixed and stirred for 7 minutes, and ultrasonically treated for 12 minutes to obtain alumina colloidal sol. 90 parts of high-purity quartz sand were added and stirred at room temperature for 5 hours. After standing for 2 hours, solid and liquid were separated, the precipitate was dried, and sintered at 1200℃ for 2.5 hours to obtain composite aggregate.

[0043] 26 parts of fused silica fiber were immersed in 500 parts of 70% (v / v) ethanol aqueous solution, sonicated for 12 min, removed, rinsed twice with deionized water, and dried in an oven at 90℃ for 1.5 h to obtain pretreated fused silica fiber; 28.5 parts of ZrOCl2·8H2O, 23 parts of Y(NO3)3·6H2O, 110 parts of deionized water and 45 parts of anhydrous ethanol were mixed and magnetically stirred at 220 rpm for 18 min, and 23 parts of 7.8% (w / w) citric acid solution were added dropwise at 70℃. After stirring continuously for 40 min, 19 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 4 h. After cooling to room temperature, a mixed sol was obtained. 16 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 220 rpm for 1.5 h at room temperature. The fiber was then removed, allowed to stand for 2.5 h, dried at 110℃ for 2 h, and then placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 h. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 h. After cooling to room temperature, modified fused silica fiber was obtained.

[0044] Five parts of tar and ten parts of silica sol were mixed and stirred for 5 minutes. Then, 0.16 parts of aluminum dihydrogen phosphate were added and stirred continuously for 7 minutes. The mixture was then ultrasonically treated for 13 minutes to obtain a tar-silica sol suspension. Seventy-five parts of natural quartz were coarsely crushed in a pulverizer, rinsed three times with deionized water, dried at 110°C for 20 hours, and then placed in a muffle furnace. The temperature was increased to 350°C at a rate of 3°C / min and held for 1.5 hours. Finally, the temperature was increased to 1100°C at a rate of 5°C / min. The material was kept at a constant temperature for 2.5 hours, then heated to 1300℃ and kept at that temperature for 1.5 hours. It was then slowly cooled to room temperature in the furnace to obtain pre-fired quartz stone. 50 parts of pre-fired quartz stone, 33 parts of composite aggregate, 5 parts of alumina micro powder, 8 parts of silica micro powder, 12 parts of modified fused silica fiber, and 2 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 3 minutes. Then, 15.16 parts of tar-silica sol suspension and 10 parts of deionized water were added and mixed for 7 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0045] Example 4

[0046] By weight, 47 parts of nano alumina were added to 180 parts of deionized water, mixed and stirred for 7 minutes, and ultrasonically treated for 12 minutes to obtain alumina colloidal sol. 85 parts of high-purity quartz sand were added and stirred at room temperature for 4.5 hours. After standing for 2 hours, solid and liquid were separated, the precipitate was dried, and sintered at 1200℃ for 2.5 hours to obtain composite aggregate.

[0047] 27 parts of fused silica fiber were immersed in 500 parts of 70% (v / v) ethanol aqueous solution, ultrasonically treated for 12 min, removed, rinsed twice with deionized water, and dried in an oven at 90℃ for 1.5 h to obtain pretreated fused silica fiber; 29 parts of ZrOCl2·8H2O, 23 parts of Y(NO3)3·6H2O, 110 parts of deionized water and 47 parts of anhydrous ethanol were mixed and magnetically stirred at 260 rpm for 15 min, and 22 parts of 7.8% (w / w) citric acid solution were added dropwise, and stirring was continued at 70℃. After stirring for 45 min, 19.5 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 4.5 h. After cooling to room temperature, a mixed sol was obtained. 18 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 260 rpm for 1.5 h at room temperature. The fiber was then removed, allowed to stand for 2.2 h, dried at 115℃ for 2 h, and then placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 h. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 h. After cooling to room temperature, modified fused silica fiber was obtained.

[0048] A tar-silica sol suspension was prepared by mixing 4.5 parts of tar and 10 parts of silica sol for 5 minutes, adding 0.16 parts of aluminum dihydrogen phosphate, stirring continuously for 8 minutes, and then sonicating for 14 minutes. A coarse crushing of 76 parts of natural quartz was then performed in a pulverizer, followed by rinsing three times with deionized water, drying at 105℃ for 20 hours, and then heating in a muffle furnace to 400℃ at a rate of 3℃ / min and holding for 1.5 hours, followed by heating to 1050℃ at a rate of 5℃ / min. The material was kept at a constant temperature for 2.2 hours, then heated to 1280℃ and kept at that temperature for 1.5 hours. It was then slowly cooled to room temperature in the furnace to obtain pre-fired quartz stone. 42 parts of pre-fired quartz stone, 34 parts of composite aggregate, 2 parts of alumina micro powder, 6 parts of silica micro powder, 11 parts of modified fused silica fiber, and 1.8 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 4 minutes. Then, 14.66 parts of tar-silica sol suspension and 6 parts of deionized water were added and mixed for 9 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0049] Example 5

[0050] By mass, 42 parts of nano alumina were added to 180 parts of deionized water, mixed and stirred for 10 min, and ultrasonically treated for 10 min to obtain alumina colloidal sol. 80 parts of high-purity quartz sand were added and stirred at room temperature for 6 h. After standing for 2 h, solid-liquid separation was performed, the precipitate was dried, and sintered at 1300℃ for 2.2 h to obtain composite aggregate.

[0051] 25 parts of fused silica fiber were immersed in 500 parts of 70% (v / v) ethanol aqueous solution, sonicated for 15 min, removed, rinsed once with deionized water, and dried in an oven at 80℃ for 1.6 h to obtain pretreated fused silica fiber; 30 parts of ZrOCl2·8H2O, 22 parts of Y(NO3)3·6H2O, 105 parts of deionized water and 42 parts of anhydrous ethanol were mixed and magnetically stirred at 300 rpm for 10 min, and 22 parts of 7.8% (w / w) citric acid solution were added dropwise, and the mixture was kept at 70℃. After stirring for 50 min, 18 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 5 h. After cooling to room temperature, a mixed sol was obtained. 15 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 300 rpm for 1.5 h at room temperature. The fiber was then removed, allowed to stand for 2.2 h, dried at 100℃ for 2 h, and then placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 h. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 h. After cooling to room temperature, modified fused silica fiber was obtained.

[0052] A tar-silica sol suspension was prepared by mixing 3.5 parts of tar and 10 parts of silica sol for 5 minutes, then adding 0.16 parts of aluminum dihydrogen phosphate and stirring continuously for 5 minutes, followed by ultrasonic treatment for 15 minutes. 80 parts of natural quartz were coarsely crushed in a pulverizer, rinsed twice with deionized water, dried at 105℃ for 24 hours, and then placed in a muffle furnace. The temperature was increased to 310℃ at a rate of 3℃ / min and held for 1.2 hours, followed by further increasing to 106℃ at a rate of 5℃ / min. Pre-fired quartz stone was obtained by holding the material at 0℃ for 2.5 hours, raising the temperature to 1260℃, holding it at 1 hour, and then slowly cooling it to room temperature in the furnace. 40 parts of pre-fired quartz stone, 32 parts of composite aggregate, 1 part of alumina micro powder, 8 parts of silica micro powder, 10 parts of modified fused silica fiber, and 2 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 2 minutes. Then, 13.66 parts of tar-silica sol suspension and 7 parts of deionized water were added and mixed for 10 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0053] Example 6

[0054] By weight, 42 parts of nano alumina were added to 160 parts of deionized water, mixed and stirred for 8 minutes, and ultrasonically treated for 12 minutes to obtain alumina colloidal sol. 88 parts of high-purity quartz sand were added and stirred at room temperature for 5.5 hours. After standing for 2 hours, solid and liquid were separated, the precipitate was dried, and sintered at 1180℃ for 2.5 hours to obtain composite aggregate.

[0055] Twenty parts of fused silica fiber were immersed in 500 parts of a 70% (v / v) ethanol aqueous solution, sonicated for 15 min, removed, rinsed three times with deionized water, and dried in a 95℃ oven for 2 h to obtain pretreated fused silica fiber. Twenty-eight parts of ZrOCl2·8H2O, 23.5 parts of Y(NO3)3·6H2O, 105 parts of deionized water, and 42 parts of anhydrous ethanol were mixed and magnetically stirred at 220 rpm for 15 min. Twenty-four parts of a 7.8% (w / w) citric acid solution were then added dropwise, and the mixture was kept at 70℃. After stirring for 35 minutes, 19 parts of ethylene glycol were added, the temperature was raised to 85℃ and stirring was continued for 4 hours. After cooling to room temperature, a mixed sol was obtained. 16 parts of pretreated fused silica fiber were added, and the mixture was magnetically stirred at 220 rpm for 1.5 hours at room temperature. The fiber was then removed, allowed to stand for 2.5 hours, dried at 110℃ for 2 hours, and placed in a muffle furnace. The temperature was raised to 600℃ at a rate of 2℃ / min and held for 1 hour. The temperature was then raised to 1350℃ at a rate of 5℃ / min and held for 2 hours. After cooling to room temperature, modified fused silica fiber was obtained.

[0056] After coarsely crushing 80 parts of natural quartz stone in a pulverizer, it was rinsed twice with deionized water, dried at 120℃ for 18 hours, and then placed in a muffle furnace. The temperature was raised to 400℃ at a rate of 3℃ / min and held for 1 hour, then raised to 1100℃ at a rate of 5℃ / min and held for 2 hours, and then raised to 1250℃ and held for 2 hours. The temperature was then slowly cooled to room temperature in the furnace to obtain pre-fired quartz stone. 50 parts of pre-fired quartz stone, 30 parts of composite aggregate, 5 parts of alumina micro powder, 4 parts of silica micro powder, 15 parts of modified fused silica fiber, and 1.5 parts of aluminum hexametaphosphate were placed in a mortar mixer and mixed for 5 minutes. Then 10 parts of deionized water were added and mixed for 5 minutes to obtain quartz stone-based steel ladle refractory casting material.

[0057] The present invention also includes comparative examples and related experiments.

[0058] Comparative Example 1

[0059] Compared with Example 1, the only difference is that quartz stone is used directly instead of composite aggregate, while the other preparation methods and components are completely consistent, and finally quartz stone-based steel ladle refractory casting material is obtained.

[0060] Comparative Example 2

[0061] Compared with Example 1, the only difference is that fused silica fiber is used directly instead of modified fused silica fiber. The other preparation methods and components are completely the same, and finally, quartz-based steel ladle refractory casting material is obtained.

[0062] Comparative Example 3

[0063] Compared with Example 1, the only difference is that no modified fused silica fiber was added. The other preparation methods and components are completely the same, and the quartz-based steel ladle refractory casting material is finally obtained.

[0064] Performance testing

[0065] The quartz-based steel ladle refractory castables prepared in Examples 1-6 and Comparative Examples 1-3 were further tested using the following specific experimental procedures:

[0066] The quartz-based steel ladle refractory castables prepared in Examples 1-6 and Comparative Examples 1-3 were placed into molds, poured in layers, and vibrated to form the refractory material. After the surface was smoothed, the materials were allowed to cure at room temperature for 24 hours. After demolding, the materials were dried at 80°C for 12 hours, then preheated at 200°C and held at that temperature. Subsequently, the materials were placed in a muffle furnace and heated to 600°C at a rate of 5°C / min, held at that temperature for 1 hour, and then heated to 1350°C and held at that temperature for 2 hours. The materials were then cooled to room temperature with the furnace to obtain densely formed refractory material samples. The obtained samples were cut and polished to the specified dimensions and then used to test indicators such as bulk density, apparent porosity, room temperature compressive strength, high temperature flexural strength, thermal shock resistance, and slag erosion resistance.

[0067] The basic properties of the samples at room temperature were tested according to GB / T2997-2015 "Test Methods for Bulk Density, Apparent Porosity and True Porosity of Dense Shaped Refractory Products", GB / T5072-2023 "Test Methods for Compressive Strength of Refractory Materials at Room Temperature", and GB / T3001-2017 "Test Methods for Flexural Strength of Refractory Materials at Room Temperature". The specific test results of the basic properties are shown in Table 1.

[0068] Table 1: Basic Performance Test Results

[0069]

[0070] As shown in Table 1, the samples prepared using Examples 1-6 of the present invention have good mechanical properties. Example 6, due to the absence of the tar-silica sol suspension, has some impact on its bulk density and mechanical properties, but it is still significantly better than Comparative Examples 1-3. In Comparative Example 1, the mechanical strength is significantly reduced without the use of composite aggregate, and in Comparative Example 3, the mechanical strength is the worst without the addition of modified fused silica fiber.

[0071] The procedure for setting up thermal shock resistance tests on the samples finally prepared using the quartz-based steel ladle refractory castables obtained in Examples 1-6 and Comparative Examples 1-3 is as follows: The samples are placed in a furnace preheated to 1500℃ and held for 20 minutes. They are then immediately removed and immersed in cold water for 3 minutes. Subsequently, they are placed in air to dry naturally for more than 5 minutes. The above process is repeated until the end breaks to measure the thermal shock resistance of the samples. The slag erosion resistance test is carried out in accordance with GB / T8931-2007 "Test Method for Slag Resistance of Refractory Materials". The erosion area percentage C and penetration area percentage P are calculated to evaluate the slag erosion resistance. The specific calculation formulas for the erosion area percentage C (%) are shown in Equation (I) and the specific calculation formulas for the penetration area percentage P (%) are shown in Equation (II).

[0072] C= (I)

[0073] P= (II)

[0074] Where S is the total area of ​​the sample profile (mm²) 2 C1 represents the area (mm²) of the eroded sample profile. 2 P1 represents the area (mm²) of the sample cross-section that was penetrated. 2 The final test results for thermal shock resistance and slag erosion resistance are shown in Table 2.

[0075] Table 2: Test Results of Thermal Shock Resistance and Slag Erosion Resistance

[0076]

[0077] As shown in Table 2, the samples prepared using Examples 1-6 of the present invention have good thermal shock resistance and slag erosion resistance. Among them, Example 6 has a slightly lower slag erosion resistance due to the absence of tar-silica sol suspension. Comparative Example 1 has a significantly lower thermal shock resistance and a significantly higher percentage of eroded / penetrated area due to the absence of composite aggregate. In Comparative Example 3, the absence of modified fused silica fiber also significantly reduces the thermal shock resistance. This further illustrates that composite aggregate and modified fused silica fiber are the key components for achieving the thermal shock resistance and slag erosion resistance of the samples.

[0078] In addition, the samples finally prepared using the quartz-based steel ladle refractory casting materials prepared in Example 1 and Comparative Example 1 were tested at high temperature (1500℃) according to GB / T34218-2017 "Test Method for High Temperature Compressive Strength of Refractory Materials" and GBT3002-2017 "Test Method for High Temperature Flexural Strength of Refractory Materials" to evaluate their high temperature stability. The specific test results are shown in Table 3.

[0079] Table 3: High-Temperature Mechanical Property Test Results

[0080]

[0081] As shown in Table 3, the samples prepared using Examples 1-6 of the present invention can still maintain good mechanical strength at high temperature (1500℃) and have good high-temperature stability. The lack of composite aggregate in Comparative Example 1 significantly reduced the mechanical properties at high temperature. The use of fused silica fiber instead of modified fused silica fiber in Comparative Example 2 also significantly affected the mechanical properties at high temperature. This shows that modifying the surface of quartz sand and fused silica fiber can significantly improve the overall high-temperature stability of the sample.

[0082] Furthermore, the high-temperature creep resistance performance was tested according to the test method of GB / T5073-2022 Refractory Materials Compression Creep Test Method, and the final results were plotted as creep curves, such as... Figure 1 As shown; from Figure 1 It can be clearly seen that during the 124-hour test, the creep deformation of Example 1 was always significantly lower than that of Comparative Example 1. Its curve showed a slight increase, and the peak creep deformation remained within 0.62 mm within 124 hours, which was much lower than the creep deformation of Comparative Example 1, which rapidly increased to more than 0.70 mm in the later stage.

[0083] In summary, the quartz-based steel ladle refractory casting material prepared by this invention can achieve good high-temperature creep resistance and exhibits good mechanical strength and slag erosion resistance.

[0084] The above are preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of a quartzite-based ladle refractory castable material, characterized in that, The method comprises the following steps: S1, mixing and stirring alumina colloidal sol and high-purity quartz sand, standing, separating, drying, high-temperature sintering to obtain composite aggregate; S2, mixing ZrOCl2.8H2O, Y(NO3)3.6H2O, deionized water and anhydrous ethanol, adding citric acid solution dropwise, high-temperature stirring with ethylene glycol, cooling, adding pretreated fused quartz fiber and magnetically stirring, taking out the fiber, standing, drying, heat treatment, cooling to obtain modified fused quartz fiber; the heat treatment is: heating at a rate of 2℃ / min to 600℃ for 1h, continuing to heat at a rate of 5℃ / min to 1350℃ for 2h, cooling to room temperature to obtain modified fused quartz fiber S3, mixing and uniformly mixing pre-sintered quartz stone, composite aggregate, alumina powder, silicon powder, modified fused quartz fiber, aluminum hexametaphosphate, additives and deionized water to obtain quartz stone-based ladle refractory casting material; the modified fused quartz fiber comprises the following mass parts of raw materials: 28-30 parts of ZrOCl2.8H2O, 22-24 parts of Y(NO3)3.6H2O, 100-120 parts of deionized water, 40-50 parts of anhydrous ethanol, 22-25 parts of citric acid solution, 18-20 parts of ethylene glycol and 15-20 parts of pretreated fused quartz fiber; the mass concentration of the citric acid solution is 7.8%.

2. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, The alumina colloidal sol is obtained by mixing and stirring 40-50 mass parts of nano-alumina in 150-200 volume parts of deionized water for 5-10 min and ultrasonic treatment for 10-15 min.

3. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, In the step S1, the alumina colloidal sol and 80-90 mass parts of high-purity quartz sand are stirred at room temperature for 4-6h, and after standing for 2h, the solid-liquid separation is performed, the precipitate is dried, and sintering is performed at 1100-1300℃ for 2-3h to obtain the composite aggregate.

4. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, The pretreated fused quartz fiber is obtained by immersing the fused quartz fiber in an ethanol aqueous solution with a volume concentration of 70%, ultrasonic treatment for 10-15 min, taking out, washing with deionized water for 1-3 times, and drying in an oven at 80-100℃ for 1-2h.

5. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, In the step S2, ZrOCl2.8H2O, Y(NO3)3.6H2O, deionized water and anhydrous ethanol are mixed, magnetically stirred at a rate of 200-300rpm for 10-20 min, citric acid solution is added dropwise, and after continuous stirring at 70℃ for 30-50 min, ethylene glycol is added, the temperature is increased to 85℃, and the stirring is continued for 3-5h, the mixture is cooled to room temperature to obtain a mixed sol, the pretreated fused quartz fiber is added, and after magnetically stirring at a rate of 200-300rpm for 1-2h at room temperature, the fiber is taken out, stands for 2-3h, dried at 100-120℃ for 2h, placed in a muffle furnace, heated at a rate of 2℃ / min to 600℃ for 1h, and then heated at a rate of 5℃ / min to 1350℃ for 2h, and cooled to room temperature to obtain modified fused quartz fiber.

6. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, The pre-fired quartz stone is obtained by the following steps: 70-80 parts by mass of natural quartz stone is coarsely crushed in a crusher, then washed with deionized water for 2-4 times, dried at 100-120 DEG C for 18-24 hours, then placed in a muffle furnace, heated at a rate of 3 DEG C / min to 300-400 DEG C, kept for 1-2 hours, then heated at a rate of 5 DEG C / min to 1000-1100 DEG C, kept for 2-3 hours, heated to 1250-1300 DEG C, kept for 1-2 hours, and then slowly cooled to room temperature in the furnace.

7. The process for preparing a quartzite-based steel ladle refractory castable material according to claim 1, characterized in that, In the step S3, the pre-fired quartz stone, the composite aggregate, the alumina micropowder, the silica micropowder, the modified fused quartz fiber and the aluminum hexametaphosphate are placed in a mortar mixer, mixed and stirred for 2-5 minutes, then the additives and deionized water are added and mixed and stirred for 5-10 minutes, thereby obtaining the quartz stone-based ladle refractory casting material.

8. The process for preparing a quartzite based steel ladle refractory castable material as claimed in claim 1 wherein, The additives are a tar-silica sol suspension, which is prepared by mixing and stirring 3-5 parts by mass of tar and 10 parts by mass of silica sol for 5 minutes, then continuously stirring 0.16 parts by mass of aluminum dihydrogen phosphate for 5-10 minutes, and then ultrasonic treatment for 10 minutes.

9. A quartzite-based ladle refractory castable material, characterized in that, The quartz stone-based ladle refractory casting material is prepared by the preparation process of any one of claims 1-8, and includes the following raw materials: 40-50 parts by mass of pre-fired quartz stone, 30-35 parts by mass of composite aggregate, 1-5 parts by mass of alumina micropowder, 4-8 parts by mass of silica micropowder, 10-15 parts by mass of modified fused quartz fiber, 1.5-2 parts by mass of aluminum hexametaphosphate, 5-10 parts by mass of deionized water, and 13.16-15.16 parts by mass of additives.

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