Preparation method of medium-low temperature wear-resistant castable for lithium salt industry

Abstract

The invention discloses a preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry. The preparation method comprises the following steps: S1, dry mixing of raw materials; S2, preparation of a wear-resistant composite material; and S3, wet mixing and stirring. According to the method disclosed by the invention, the wear resistance of the castable is enhanced by compounding the light mullite and the phenolic resin, and the thermal shock resistance of the material is improved by floating a low-density light mullite sheet to form a wear-resistant surface layer; the tensile strength and toughness of the material are effectively enhanced and the crack resistance of the castable is improved through the surface activation treatment and hot pressing process of the carbon fibers; through the synergistic effect of SiC and ZrO2, SiC provides high hardness and wear resistance, ZrO2 enhances the toughness and thermal stability of the material, and the comprehensive performance of the castable under the medium and low temperature working conditions is remarkably improved by combining the accurate proportioning of the dry blend and the ultrasonic wet mixing and stirring technology.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of castable preparation, in particular to a preparation method of a medium-low temperature wear-resistant castable for a lithium salt industry. BACKGROUND

[0002] As an important part of the new energy industry, the lithium salt industry has rapidly grown in recent years with the rapid development of energy storage systems and electronic devices, especially in high-temperature process such as lithium salt smelting, electrolysis and recycling. The lining materials of equipment and devices are subjected to extreme temperature and wear challenges.

[0003] As a key refractory material, the performance of the medium-low temperature wear-resistant castable directly affects the production efficiency, safety and cost. Although the traditional castable performs excellently in some aspects, its limitations become obvious when it faces the high corrosiveness and complex thermodynamic environment unique to the lithium salt industry, mainly in the aspects of insufficient wear resistance, poor thermal stability and easy structural degradation under medium-low temperature working conditions.

[0004] In the lithium salt production process, under the combined action of high temperature and corrosive medium, the castable is prone to chemical erosion, which leads to the degradation of the performance of the lining material and affects the stable operation of the equipment. The flow of materials and the flow of air in lithium salt production test the wear resistance of the castable, and severe wear will shorten the maintenance cycle of the equipment and increase the maintenance cost. Under the medium-low temperature environment, the material has insufficient thermal stability and is prone to cracking and peeling, especially when the temperature changes suddenly, the material has poor thermal shock stability, which easily leads to the damage of the lining.

[0005] The existing wear-resistant castable construction process is complex, has a long solidification time, has high requirements for the construction environment, and is difficult to repair quickly during maintenance, thereby affecting the production efficiency. SUMMARY

[0006] In order to solve the above problems, the application provides a preparation method of a medium-low temperature wear-resistant castable for a lithium salt industry.

[0007] The technical scheme of the application is as follows: a preparation method of a medium-low temperature wear-resistant castable for a lithium salt industry, comprising the following steps:

[0008] S1, dry mixing of raw materials:

[0009] 10-15% of SiC, 6-10% of ZrO2, 6-10% of CA-70 silicate cement, 5-10% of SiO2, 6-8% of corundum, 4-6% of pure calcium aluminate cement, 3-5% of auxiliary agent, 2-4% of alumina micropowder, 1-3% of silicon micropowder and the balance of brown corundum powder are uniformly mixed for 5-15 min according to the mass percentage to obtain a dry mixture;

[0010] S2, preparation of wear-resistant composite material:

[0011] S2-1, light mullite powder with particle size of 0.1-0.5mm is introduced into a mold, and after vibration forming, the light mullite sheet is obtained by demolding and sintering;

[0012] S2-2, the phenolic resin agent is prepared, the light mullite sheet is immersed in the phenolic resin agent, and then cured at 115-125℃ for 1-3h, and then cured at 175-185℃ for 1.5-2.5h to obtain a phenolic resin composite mullite material;

[0013] S2-3, the carbon fiber is surface-activated, the surface-activated carbon fiber is laid on the surface of the phenolic resin composite mullite material, and the average thickness of the laid carbon fiber is 1-4mm; then the carbon fiber is placed in a hot press for hot pressing, the hot pressing temperature is 175-185℃, the pressure is 5-8MPa, and the pressing time is 10-15min to obtain a wear-resistant composite material;

[0014] S3, wet mixing and stirring:

[0015] In the dry mixture described in S1, the wear-resistant composite material accounts for 10-28wt% of the dry mixture, the nano material accounts for 10-15wt%, the polymeric aluminum oxalate accounts for 5-10wt%, and the water accounts for 30-48wt%, and then ultrasonic stirring is performed to obtain a wear-resistant castable.

[0016] Description: By controlling the composition and ratio of raw materials, the high strength and wear resistance of the castable are ensured, the wear resistance is improved, the light mullite sheet provides additional wear resistance and light weight characteristics, the overall density is reduced, and the thermal stress is reduced; the phenolic resin is cured at high temperature to enhance the adhesion and heat resistance of the material; through surface activation and hot pressing treatment, the carbon fiber and the phenolic resin form a strong bond, which significantly improves the tensile strength and crack resistance of the castable.

[0017] Further, according to the mass fraction, the SiC described in S1 includes 2-3 parts of SiC with particle size of 300-325 mesh, 2-3 parts of SiC with particle size of 0-1mm, 1-2 parts of SiC with particle size of 1-3mm, and 3-4 parts of SiC with particle size of 3-5mm; the brown corundum powder includes 10-11 parts of brown corundum powder with particle size of 180-190 mesh, 11-12 parts of brown corundum powder with particle size of 0-1mm, 12-13 parts of brown corundum powder with particle size of 1-3mm, and 18-19 parts of brown corundum powder with particle size of 3-5mm; the particle size of ZrO2 is 0.02-0.08mm, the particle size of SiO2 is 0.001-0.05mm, the particle size of corundum is 300-325 mesh, and the particle size of alumina micropowder is 300-325 mesh.

[0018] Explanation: Larger-diameter SiC particles provide good wear resistance and compressive strength while maintaining material flowability, facilitating construction; nano-sized ZrO2 significantly enhances the material's toughness and thermal stability, and its smaller particle size helps improve the density of the castable and reduce the formation of microcracks; ultrafine SiO2 particles can fill smaller pores, further improving the density and wear resistance of the castable, while promoting internal chemical bonding; smaller-diameter brown corundum powder improves the wear resistance of the castable surface, medium-diameter particles provide the structural framework of the castable, enhancing compressive and impact resistance, and larger particle sizes help improve the thermal stability and crack resistance of the castable, while reducing the overall coefficient of thermal expansion.

[0019] Furthermore, the auxiliary agent mentioned in S1 is composed of water-reducing agent, UEA expanding agent, and explosion-proof agent in a mass ratio of 1:1 to 1.5:1.

[0020] Explanation: By precisely controlling the ratio of water-reducing agent, UEA expanding agent, and explosion-proof agent, the synergistic effect among them is optimized, maintaining the high strength and low porosity of the castable while effectively controlling the shrinkage and cracks that may occur during the hardening process, and ensuring the thermal stability and safety of the material.

[0021] Furthermore, the vibration frequency of S2-1 is 30-50Hz, the amplitude is 1-2mm, and the vibration molding time is 8-15min; the average length of the lightweight mullite sheet is 1-8mm, the width is 1-6mm, and the thickness is 0.5-2mm.

[0022] Note: By precisely controlling the vibration frequency, amplitude, and time, the microstructure of lightweight mullite flakes is optimized, improving the material's density and strength, reducing porosity, and enhancing wear resistance and thermal stability.

[0023] Further, the sintering method described in S2-1 is as follows: the temperature is increased from room temperature to 200-300℃ at a heating rate of 10-15℃ / min, held for 1-2 hours, and then increased to 1400-1600℃ at a heating rate of 5-10℃ / min, held for 3-4 hours, and then cooled naturally.

[0024] Explanation: Rapid preheating removes moisture and any potential organic matter from the material, preventing porosity or cracks during high-temperature sintering. Holding at 200–300°C allows for the pre-adjustment of the material's microstructure, preparing it for subsequent high-temperature sintering. Controlling the heating rate ensures uniform heating within the material, promoting the transformation of the mullite crystal phase and accelerating grain densification, reducing porosity and improving the material's strength and wear resistance. Prolonged high-temperature holding promotes grain growth and microstructure optimization, enhancing the material's thermal stability and thermal shock resistance. Slow natural cooling helps release internal stress, reducing stress concentration and crack formation caused by rapid cooling, thus ensuring the integrity of the lightweight mullite sheets.

[0025] Further, the surface activation treatment method for the carbon fiber described in S2-3 is as follows: ultrasonic cleaning of the carbon fiber using acetone, wherein the ultrasonic cleaning frequency is 35-45 kHz, the cleaning time is 10-20 min, and the power density is 0.3-3 W / cm². 2 Then, at 60–80°C, the cleaned carbon fibers are immersed in a concentrated nitric acid solution for 1–3 hours to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane is dissolved in ethanol, with the concentration of γ-glycidyltrimethoxysilane in ethanol controlled at 1–10%, to obtain a grafting agent solution. The oxidized carbon fibers are immersed in the grafting agent solution at 50–100°C and stirred for 10–20 hours to perform surface treatment. After completion, the carbon fibers are removed, washed with deionized water, and then dried at 75–85°C to remove residual solvent and moisture from the surface.

[0026] Note: Acetone effectively removes oil and dust from the carbon fiber surface, and ultrasonic cleaning further enhances the cleaning effect, ensuring efficient subsequent processing. At 60–80°C, carbon fibers in concentrated nitric acid solution undergo oxidation treatment, increasing surface functional groups such as carboxyl or hydroxyl groups, thus improving surface activity and reactivity. The interfacial bonding between the oxidized carbon fibers and the matrix material is strengthened, improving the overall performance of the composite material. γ-glycidyltrimethoxysilane dissolves in ethanol to form a grafting agent solution; the carbon fibers react with this solution at 50–100°C to form chemical bonds, further enhancing surface activity. The compatibility and adhesion between the grafted carbon fibers and the phenolic resin-mullite composite material are significantly enhanced, improving the mechanical properties and durability of the composite material. Drying ensures that the surface of the treated carbon fibers is free of residual solvent and moisture, preventing performance instability during subsequent use.

[0027] Furthermore, the ultrasonic stirring speed described in S3 is 300-600 rpm / min, and the stirring time is 15-30 min.

[0028] Explanation: Ultrasonic stirring at a rate of 300–600 rpm / min generates a strong cavitation effect through high-frequency vibration, effectively breaking up agglomerates in the liquid, resulting in uniform dispersion of powder particles and improved mixing homogeneity. Ultrasonic waves accelerate the diffusion of reactants at the interface, promoting interfacial reactions and facilitating the formation of a more stable composite structure. A stirring time of 15–30 minutes is sufficient to ensure adequate contact and reaction between reactants, reducing unmixed areas and improving material homogeneity. Ultrasonic stirring results in more uniform material mixing and more complete interfacial reactions, significantly improving the mechanical properties and thermal stability of composite materials. Reasonable control of stirring rate and time optimizes the material preparation process, improving production efficiency and material quality.

[0029] Furthermore, the nanomaterial described in S3 consists of 35–45 wt% nanographite, 20–30 wt% MXene, and the balance TiB2 nanoparticles.

[0030] Explanation: The high electrical conductivity of MXene combined with the high strength and high hardness of TiB2 significantly enhances the electrical and mechanical properties of the material; nano-graphite not only optimizes the microstructure and improves the wear resistance of the material, but also improves the interfacial bonding. Together with TiB2 and MXene, it further optimizes the electrical conductivity, mechanical properties, thermal stability and wear resistance. By finely controlling the proportion of each component and the microstructure, the wear resistance of the castable is improved.

[0031] The beneficial effects of this invention are:

[0032] (1) The method of the present invention utilizes the synergistic effect of SiC and ZrO2. SiC provides high hardness and wear resistance, while ZrO2 enhances the toughness and thermal stability of the material. The combined use significantly improves the comprehensive performance of the castable under medium and low temperature conditions. The composite of lightweight mullite and phenolic resin enhances the wear resistance of the castable by combining lightweight mullite flakes with phenolic resin. The formation of a wear-resistant surface layer by the floating of low-density lightweight mullite flakes improves the thermal shock resistance of the material. The surface activation treatment and hot pressing process of carbon fiber effectively enhance the tensile strength and toughness of the material and improve the crack resistance of the castable.

[0033] (2) The combination of precise proportioning of dry mix with ultrasonic wet mixing technology ensures uniform distribution of material components, avoids the generation of pores and cracks, and improves the density and stability of castable; the addition of nanomaterials refines the microstructure, enhances the wear resistance and corrosion resistance of castable, and at the same time, the high activity of nanomaterials promotes the formation of chemical bonds and improves the bonding strength of the material. Detailed Implementation

[0034] Example 1: A method for preparing a medium-low temperature wear-resistant castable for the lithium salt industry, comprising the following steps:

[0035] S1. Dry mixing of raw materials:

[0036] By mass percentage, take 12.5% ​​SiC, 8% ZrO2, 8% CA-70 silicate cement, 7.5% SiO2, 7% corundum, 5% pure calcium aluminate cement, 4% additives, 3% alumina powder, 2% silica powder, and the balance brown corundum powder and mix them evenly for 10 minutes to obtain dry mix.

[0037] By mass fraction, the SiC in S1 comprises: 2 parts SiC with a particle size of 310-315 mesh, 2 parts SiC with a particle size of 0.5-0.8 mm, 1 part SiC with a particle size of 1.5-2 mm, and 2 parts SiC with a particle size of 3.5-4.5 mm; the brown fused alumina powder comprises: 10 parts brown fused alumina powder with a particle size of 185-186 mesh, 11 parts brown fused alumina powder with a particle size of 0.5-0.8 mm, 12 parts brown fused alumina powder with a particle size of 1.5-2 mm, and 18 parts brown fused alumina powder with a particle size of 3.5-4 mm; the ZrO2 has a particle size of 0.05-0.06 mm, the SiO2 has a particle size of 0.003-0.04 mm, the fused alumina has a particle size of 310-315 mesh, and the alumina micro powder has a particle size of 310-315 mesh.

[0038] The auxiliary agent is composed of water-reducing agent, UEA expanding agent, and explosion-proof agent in a mass ratio of 1:1.25:1;

[0039] S2. Preparation of wear-resistant composite materials:

[0040] S2-1. Lightweight mullite powder with a particle size of 0.3-0.4 mm is introduced into a mold, vibrated and molded, then demolded and sintered to obtain lightweight mullite sheets; the vibration frequency is 40 Hz, the amplitude is 1.5 mm, and the vibration molding time is 11.5 min; the average length of the lightweight mullite sheets is 4.5 mm, the width is 3.5 mm, and the thickness is 12.5 mm; the sintering method is as follows: the temperature is increased from room temperature to 250℃ at a heating rate of 12.5℃ / min, held for 1.5 h, then increased to 1500℃ at a heating rate of 7.5℃ / min, held for 3.5 h, and then naturally cooled;

[0041] S2-2. Prepare phenolic resin agent, immerse lightweight mullite sheets in phenolic resin agent, cure at 120℃ for 2 hours, and then continue to cure at 180℃ for 2 hours to obtain phenolic resin composite mullite material.

[0042] S2-3. Surface-activated carbon fibers are then laid on the surface of a phenolic resin composite mullite material, with an average thickness of 2 mm. Subsequently, the material is hot-pressed in a hot press at a temperature of 180℃, a pressure of 6.5 MPa, and a pressing time of 12.5 min to obtain a wear-resistant composite material. The surface activation treatment method for the carbon fibers is as follows: ultrasonic cleaning of the carbon fibers using acetone at a frequency of 40 kHz for 15 min at a power density of 2 W / cm². 2 Then, at 70°C, the cleaned carbon fibers were immersed in a concentrated nitric acid solution for 2 hours to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane was dissolved in ethanol, and the concentration of γ-glycidyltrimethoxysilane in ethanol was controlled at 5% to obtain a grafting agent solution. The oxidized carbon fibers were immersed in the grafting agent solution at 75°C and stirred for 15 hours to perform surface treatment. After completion, the carbon fibers were taken out, washed with deionized water, and then dried at 80°C to remove residual solvent and moisture from the surface.

[0043] S3. Wet mixing:

[0044] In the dry mix described in S1, 19 wt% of the wear-resistant composite material, 12.5 wt% of the nanomaterial, 7.5 wt% of the polymeric aluminum oxalate, and 39 wt% of water were added, and then ultrasonic stirring was performed to obtain the wear-resistant castable. The ultrasonic stirring rate was 450 rpm / min, and the stirring time was 22.5 min. The nanomaterial consisted of 40 wt% nano-graphite, 25 wt% MXene, and the balance TiB2 nanoparticles.

[0045] Example 2: This example differs from Example 1 in that: by mass percentage, 10% SiC, 6% ZrO2, 6% CA-70 silicate cement, 5% SiO2, 6% corundum, 4% pure calcium aluminate cement, 3% additives, 2% alumina micro powder, 1% silica micro powder, and the remainder brown corundum powder are uniformly mixed for 5 minutes to obtain a dry mix.

[0046] Example 3: This example differs from Example 1 in that: by mass percentage, 15% SiC, 10% ZrO2, 10% CA-70 silicate cement, 10% SiO2, 8% corundum, 6% pure calcium aluminate cement, 5% additives, 4% alumina micro powder, 3% silica micro powder, and the remainder brown corundum powder are uniformly mixed for 15 minutes to obtain a dry mix.

[0047] Example 4: This example differs from Example 1 in the following ways: S2-1, Lightweight mullite powder with a particle size of 0.1-0.2 mm is introduced into a mold; S2-2, A phenolic resin agent is prepared, and the lightweight mullite flakes are immersed in the phenolic resin agent, cured at 115°C for 1 hour, and then cured at 175°C for another 1.5 hours to obtain a phenolic resin composite mullite material; S2-3, Carbon fibers are surface-activated, and the surface-activated carbon fibers are laid on the surface of the phenolic resin composite mullite material with an average thickness of 1 mm; then, it is placed in a hot press for hot pressing at a temperature of 175°C, a pressure of 5 MPa, and a pressing time of 10 minutes to obtain a wear-resistant composite material.

[0048] Example 5: This example differs from Example 1 in the following ways: S2-1, Lightweight mullite powder with a particle size of 0.4-0.5 mm is introduced into a mold; S2-2, A phenolic resin agent is prepared, and lightweight mullite flakes are immersed in the phenolic resin agent, cured at 125°C for 3 hours, and then cured at 185°C for another 2.5 hours to obtain a phenolic resin composite mullite material; S2-3, Carbon fibers are surface-activated, and the surface-activated carbon fibers are laid on the surface of the phenolic resin composite mullite material with an average thickness of 4 mm; then, it is placed in a hot press for hot pressing at a temperature of 185°C, a pressure of 8 MPa, and a pressing time of 15 minutes to obtain a wear-resistant composite material.

[0049] Example 6: This example differs from Example 1 in that: 10 wt% of the wear-resistant composite material, 10 wt% of the nanomaterial, 5 wt% of the polymeric aluminum oxalate, and 30 wt% of water are added to the dry mixture described in S1, and then ultrasonic stirring is performed to obtain the wear-resistant castable.

[0050] Example 7: This example differs from Example 1 in that: 28 wt% of the wear-resistant composite material, 15 wt% of nanomaterials, 10 wt% of polyaluminum oxalate and 48 wt% of water are added to the dry mixture described in S1, and then ultrasonic stirring is performed to obtain the wear-resistant castable.

[0051] Example 8: This example differs from Example 1 in that, by mass parts, the SiC in S1 comprises: 2-2.5 parts of SiC with a particle size of 300-310 mesh, 2 parts of SiC with a particle size of 0-0.5 mm, 1 part of SiC with a particle size of 1-1.5 mm, and 3 parts of SiC with a particle size of 3-3.5 mm; the brown fused alumina powder comprises: 10 parts of brown fused alumina powder with a particle size of 180-185 mesh, 11 parts of brown fused alumina powder with a particle size of 0-0.5 mm, 12 parts of brown fused alumina powder with a particle size of 1-1.5 mm, and 18 parts of brown fused alumina powder with a particle size of 3-3.5 mm; the ZrO2 has a particle size of 0.02-0.04 mm, the SiO2 has a particle size of 0.001-0.03 mm, the fused alumina has a particle size of 300-310 mesh, and the alumina micro powder has a particle size of 300-310 mesh.

[0052] Example 9: This example differs from Example 1 in that, by mass parts, the SiC in S1 comprises: 3 parts SiC with a particle size of 315-325 mesh, 3 parts SiC with a particle size of 0.8-1 mm, 2 parts SiC with a particle size of 2.5-3 mm, and 3.5-4 parts SiC with a particle size of 4.5-5 mm; the brown fused alumina powder comprises: 11 parts brown fused alumina powder with a particle size of 185-190 mesh, 12 parts brown fused alumina powder with a particle size of 0.8-1 mm, 13 parts brown fused alumina powder with a particle size of 2.5-3 mm, and 19 parts brown fused alumina powder with a particle size of 4.5-5 mm; the ZrO2 has a particle size of 0.05-0.08 mm, the SiO2 has a particle size of 0.003-0.05 mm, the fused alumina has a particle size of 315-325 mesh, and the alumina micro powder has a particle size of 315-325 mesh.

[0053] Example 10: The difference between this example and Example 1 is that the auxiliary agent mentioned in S1 is composed of water-reducing agent, UEA expansion agent and explosion-proof agent in a mass ratio of 1:1:1.

[0054] Example 11: The difference between this example and Example 1 is that the auxiliary agent mentioned in S1 is composed of water-reducing agent, UEA expansion agent and explosion-proof agent in a mass ratio of 2:3:2.

[0055] Example 12: This example differs from Example 1 in that: the vibration frequency of S2-1 is 30Hz, the amplitude is 1mm, and the vibration molding time is 8min; the average length of the lightweight mullite sheet is 1mm, the width is 1mm, and the thickness is 0.5mm.

[0056] Example 13: The difference between this example and Example 1 is that the vibration frequency of S2-1 is 50Hz, the amplitude is 2mm, and the vibration molding time is 15min; the average length of the lightweight mullite sheet is 8mm, the width is 6mm, and the thickness is 2mm.

[0057] Example 14: The difference between this example and Example 1 is that the sintering method described in S2-1 is as follows: the temperature is increased from room temperature to 200°C at a heating rate of 10°C / min, held for 1 hour, and then increased to 1400°C at a heating rate of 5°C / min, held for 3 hours, and then cooled naturally.

[0058] Example 15: The difference between this example and Example 1 is that the sintering method described in S2-1 is as follows: the temperature is increased from room temperature to 300°C at a heating rate of 15°C / min, held for 2 hours, and then increased to 1600°C at a heating rate of 10°C / min, held for 4 hours, and then cooled naturally.

[0059] Example 16: This example differs from Example 1 in that the surface activation treatment method for the carbon fiber described in S2-3 is as follows: the carbon fiber is ultrasonically cleaned using acetone at a frequency of 35 kHz for 10 minutes, with a power density of 0.3 W / cm². 2 Then, at 60°C, the cleaned carbon fibers were immersed in a concentrated nitric acid solution for 1 hour to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane was dissolved in ethanol, with the concentration of γ-glycidyltrimethoxysilane in ethanol controlled at 1%, to obtain a grafting agent solution. The oxidized carbon fibers were immersed in the grafting agent solution at 50°C and stirred for 10 hours to perform surface treatment. After completion, the carbon fibers were removed, washed with deionized water, and then dried at 75°C to remove residual solvent and moisture from the surface.

[0060] Example 17: This example differs from Example 1 in that the surface activation treatment method for the carbon fiber described in S2-3 is as follows: the carbon fiber is ultrasonically cleaned using acetone at a frequency of 45 kHz for 20 minutes, with a power density of 3 W / cm². 2 Then, at 80°C, the cleaned carbon fibers were immersed in a concentrated nitric acid solution for 3 hours to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane was dissolved in ethanol, with the concentration of γ-glycidyltrimethoxysilane in ethanol controlled at 10%, to obtain a grafting agent solution. The oxidized carbon fibers were immersed in the grafting agent solution at 100°C and stirred for 20 hours to perform surface treatment. After completion, the carbon fibers were removed, washed with deionized water, and then dried at 85°C to remove residual solvent and moisture from the surface.

[0061] Example 18: The difference between this example and Example 1 is that the ultrasonic stirring rate in S3 is 300 rpm / min and the stirring time is 15 min.

[0062] Example 19: The difference between this example and Example 1 is that the ultrasonic stirring rate in S3 is 600 rpm / min and the stirring time is 30 min.

[0063] Example 19: This example differs from Example 1 in that the nanomaterial described in S3 consists of 35 wt% nano-graphite, 20 wt% MXene, and the remainder TiB2 nanoparticles.

[0064] Example 20: This example differs from Example 1 in that the nanomaterial described in S3 consists of 45 wt% nanographite, 30 wt% MXene, and the remainder TiB2 nanoparticles.

[0065] Comparative Example 1: Referring to Example 1, step S2 is omitted, and no wear-resistant composite material is added in step S3.

[0066] Comparative Example 2: Referring to Example 1, in S3, 5 wt% of the wear-resistant composite material, 5 wt% of the nanomaterial, 2 wt% of the polymeric aluminum oxalate and 20 wt% of water were added to the dry mixture, and then ultrasonic stirring was performed to obtain the wear-resistant castable.

[0067] Comparative Example 3: Referring to Example 1, in S3, 35 wt% of the wear-resistant composite material, 25 wt% of the nanomaterial, 15 wt% of the polymeric aluminum oxalate and 53 wt% of water were added to the dry mixture, and then ultrasonic stirring was performed to obtain the wear-resistant castable.

[0068] Comparative Example 4: Referring to Example 1, carbon fibers after surface activation treatment were laid on the surface of phenolic resin composite mullite material, with an average thickness of 0.5 mm.

[0069] Comparative Example 5: Referring to Example 1, carbon fibers after surface activation treatment were laid on the surface of phenolic resin composite mullite material, with an average thickness of 5 mm.

[0070] Comparative Example 6: Referring to Example 1, no surface activation treatment was performed on the carbon fiber in S2-3.

[0071] Comparative Example 7: Referring to Example 1, the surface activation treatment method for the carbon fiber described in S2-3 is as follows: the carbon fiber is ultrasonically cleaned with acetone at a frequency of 30 kHz for 5 minutes, and the power density is 0.2 W / cm². 2Then, at 50°C, the cleaned carbon fibers were immersed in a concentrated nitric acid solution for 0.5 hours to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane was dissolved in ethanol, and the concentration of γ-glycidyltrimethoxysilane in ethanol was controlled at 0.5% to obtain a grafting agent solution. The oxidized carbon fibers were immersed in the grafting agent solution at 40°C and stirred for 8 hours to perform surface treatment. After completion, the carbon fibers were taken out, washed with deionized water, and then dried at 60°C to remove residual solvent and moisture from the surface.

[0072] To investigate the wear-resistant castable properties of Examples 1-7, 12-17, and Control Examples 1-7, the main materials were determined according to the experimental formula, and samples were prepared for testing. The test results are shown in Tables 1-4. The specific investigation is as follows:

[0073] 1. Investigate the influence of processing parameters in steps S1 to S3 on the properties of castables:

[0074] Table 1. Performance test results of samples from Examples 1 to 7

[0075]

[0076] As shown in Table 1, a comparison of Examples 1 to 7 shows that: at 100℃ for 3 hours, Example 1 exhibits the highest strength of 19 MPa, while Example 4 has the lowest strength of 14 MPa; at 800℃ for 4 hours, Example 1 also shows the best strength of 22 MPa, while Example 6 has the lowest strength of 11 MPa; it can be seen that the sample prepared using the wet mixing process parameters of Example 6 has the worst strength.

[0077] Example 1 has the lowest abrasion value, indicating that it has the best abrasion resistance; Example 4 has the highest abrasion value, indicating that its abrasion resistance is relatively poor; Example 1 has the best process parameters for preparing abrasion-resistant composite materials; Example 1 exhibits the best performance in both flexural strength and abrasion resistance under all test conditions, indicating that the optimization of its formulation and process parameters is significant.

[0078] 2. Investigate the effect of adding wear-resistant composite materials on the properties of castables:

[0079] Table 2. Performance test results of Examples 12-15 and Control Examples 1-3

[0080]

[0081]

[0082] As shown in Table 2, a comparison between Examples 12-15 and Control Examples 1-3 reveals that: Example 12 exhibits the highest flexural strength of 21 MPa at 100°C for 3 hours, while Control Example 1 shows the lowest strength under the same conditions; at 800°C for 4 hours, Example 13 exhibits the highest flexural strength, indicating good structural stability under high-temperature conditions; Example 13 also shows the lowest abrasion value of 3.1 cm. 3 This demonstrates the best wear resistance; Control Example 1 showed the highest wear value, reaching 4.2 cm. 3 Example 1 showed the worst wear resistance at high temperatures; Examples 12 and 13 showed excellent performance in both flexural strength and wear resistance, especially in high-temperature environments, indicating that the formulation and process design were reasonable; Control Example 1 showed the worst performance in both flexural strength and wear resistance, especially in high-temperature wear resistance, indicating that the addition of wear-resistant composite material has a certain impact on the performance of the castable sample.

[0083] 3. Investigate the effects of carbon fiber processing parameters and treatment on castable properties:

[0084] Table 3. Performance test results of samples from Examples 16 and 17 and Control Examples 4–7.

[0085]

[0086] As shown in Table 3, a comparison of Examples 16 and 17 with Control Examples 4-7 reveals the following: Example 16 exhibits a flexural strength of 17 MPa at 100°C for 3 hours and 14 MPa at 800°C for 4 hours, demonstrating good strength characteristics. Example 17 shows slightly lower flexural strength under the same conditions, at 15 MPa and 12 MPa respectively. Among the control examples, Control Example 5 exhibits high flexural strength in both conditions, at 18 MPa and 16 MPa respectively, but the other control examples show weaker performance, particularly in high-temperature environments. The abrasion values ​​of Examples 16 and 17 at 1100°C for 4 hours are 3.6 cm. 3 and 3.8cm 3 The results showed good wear resistance; among the control examples, Control Examples 4 and 7 had the highest wear values, at 4.1 cm and 4.1 cm, respectively. 3 and 4.0cm 3 It has poor wear resistance; it can be seen that the thickness of carbon fiber and the process parameters of surface treatment have a certain impact on strength and wear resistance.

Claims

1. A method for preparing a medium- and low-temperature wear-resistant castable for the lithium salt industry, characterized in that, Includes the following steps: S1. Dry mixing of raw materials: By mass percentage, take 10-15% SiC, 6-10% ZrO2, 6-10% CA-70 silicate cement, 5-10% SiO2, 6-8% corundum, 4-6% pure calcium aluminate cement, 3-5% additives, 2-4% alumina powder, 1-3% silica powder, and the balance brown corundum powder and mix them evenly for 5-15 minutes to obtain a dry mix. S2. Preparation of wear-resistant composite materials: S2-1. Take lightweight mullite powder with a particle size of 0.1 to 0.5 mm, put it into a mold, vibrate to form it, demold and sinter it to obtain lightweight mullite flakes. S2-2. Prepare phenolic resin agent by immersing lightweight mullite sheets in phenolic resin agent and curing at 115-125℃ for 1-3 hours, and then continuing to cure at 175-185℃ for 1.5-2.5 hours to obtain phenolic resin composite mullite material. S2-3. Surface-activation treatment of carbon fiber is carried out. The surface-activated carbon fiber is laid on the surface of phenolic resin composite mullite material with an average thickness of 1-4 mm. Then, it is placed in a hot press for hot pressing. The hot pressing temperature is 175-185℃, the pressure is 5-8 MPa, and the pressing time is 10-15 min to obtain wear-resistant composite material. S3. Wet mixing: Add the wear-resistant composite material, nanomaterials, polymeric aluminum oxalate, and water in an amount of 10-28 wt% of the dry mixture described in S1, and then perform ultrasonic stirring to obtain the wear-resistant castable.

2. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, By mass fraction, the SiC in S1 comprises: 2-3 parts SiC with a particle size of 300-325 mesh, 2-3 parts SiC with a particle size of 0-1 mm, 1-2 parts SiC with a particle size of 1-3 mm, and 3-4 parts SiC with a particle size of 3-5 mm; the brown fused alumina powder comprises: 10-11 parts brown fused alumina powder with a particle size of 180-190 mesh, 11-12 parts brown fused alumina powder with a particle size of 0-1 mm, 12-13 parts brown fused alumina powder with a particle size of 1-3 mm, and 18-19 parts brown fused alumina powder with a particle size of 3-5 mm; the ZrO2 has a particle size of 0.02-0.08 mm, the SiO2 has a particle size of 0.001-0.05 mm, the fused alumina has a particle size of 300-325 mesh, and the alumina micro powder has a particle size of 300-325 mesh.

3. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The auxiliary agent described in S1 is composed of water-reducing agent, UEA expanding agent, and explosion-proof agent in a mass ratio of 1:1 to 1.5:

1.

4. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The vibration frequency of S2-1 is 30-50Hz, the amplitude is 1-2mm, and the vibration molding time is 8-15min; the average length of the lightweight mullite sheet is 1-8mm, the width is 1-6mm, and the thickness is 0.5-2mm.

5. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The sintering method described in S2-1 is as follows: the temperature is increased from room temperature to 200-300℃ at a heating rate of 10-15℃ / min, held for 1-2 hours, and then increased to 1400-1600℃ at a heating rate of 5-10℃ / min, held for 3-4 hours, and then cooled naturally.

6. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The surface activation treatment method for carbon fibers described in S2-3 is as follows: Carbon fibers are ultrasonically cleaned with acetone, and then immersed in a 65-70 wt% concentrated nitric acid solution at 60-80°C for 1-3 hours to obtain oxidized carbon fibers. γ-glycidyltrimethoxysilane is dissolved in ethanol, with the concentration of γ-glycidyltrimethoxysilane in ethanol controlled at 1-10%, to obtain a grafting agent solution. The oxidized carbon fibers are immersed in the grafting agent solution at 50-100°C and stirred for 10-20 hours to perform surface treatment. After completion, the carbon fibers are removed, washed with deionized water, and then dried at 75-85°C to remove residual solvent and moisture from the surface.

7. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The ultrasonic stirring speed described in S3 is 300-600 rpm / min, and the stirring time is 15-30 min.

8. The preparation method of a medium-low temperature wear-resistant castable for the lithium salt industry according to claim 1, characterized in that, The nanomaterial described in S3 consists of 35–45 wt% nanographite, 20–30 wt% MXene, and the balance TiB2 nanoparticles.

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