Preparation method of thermal insulation cover lining of torpedo tank car and thermal insulation refractory castable

Abstract

The preparation method comprises the following steps: preparing raw materials: mixing and stirring mullite fine powder, tabular corundum fine powder, active SiO2 micro powder, a-Al2O3 micro powder, kyanite, Guangxi white mud and CA-70 calcium aluminate cement to obtain premixed fine powder; the preparation method comprises the following steps: stirring microporous mullite particles, alumina hollow balls and tabular corundum particles, sequentially adding premixed fine powder, surface modified stainless steel fibers, explosion-proof fibers and an additive, and continuously stirring to obtain the heat-insulating refractory castable, adding water into the heat-insulating refractory castable, injecting into the cover body of the heat-insulating cover, and vibrating and compacting to form a lining green body; curing the lining blank at room temperature, and baking to obtain the thermal insulation cover lining of the torpedo tank car; the thermal insulation refractory castable prepared by the invention and the torpedo car thermal insulation cover lining prepared based on the thermal insulation refractory castable have the comprehensive properties of light weight, low thermal conductivity, high strength, long service life and the like.

Description

Technical Field

[0001] This invention relates to the field of refractory castable technology, specifically to a method for preparing a heat-insulating cover liner for a torpedo tanker and a heat-insulating refractory castable. Background Technology

[0002] Torpedo ladle cars (also known as molten iron cars), with their large capacity and excellent insulation, have become the mainstream equipment for transporting molten iron in steel enterprises. Adding an insulated cover to the torpedo ladle car can not only effectively reduce the temperature drop of the molten iron and the precipitation of cold slag inside the ladle, but also extend the service life of the refractory materials, thus achieving significant energy-saving and consumption-reducing effects. By equipping the torpedo ladle car with an automatic cover-adding and removing device to control the insulated cover, the operation of adding and removing the insulated cover can be realized.

[0003] Most existing thermal insulation covers are composed of metal structural components and fire-resistant insulation linings. As the core of the thermal insulation cover's performance, the fire-resistant insulation lining is generally made of heavy materials with high strength and low thermal conductivity to ensure its structural strength and thermal insulation effect. This results in the large overall weight of existing thermal insulation covers, which not only increases transportation energy consumption, but also has an adverse effect on the telescopic arm, lifting mechanism, support and electrical system of the automatic covering device.

[0004] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0005] To address the aforementioned technical deficiencies, the present invention provides a method for preparing an insulation cover liner for a torpedo tanker, comprising the following steps: S1. Prepare raw materials, which include the following components in parts by weight: 100 parts of main material, 0.1-0.3 parts of additives, and 0.1-0.2 parts of explosion-proof fiber; the main material includes the following components in parts by weight: 35-50 parts of microporous mullite particles, 10-15 parts of hollow alumina spheres, 3-5 parts of tabular corundum particles, 12-20 parts of fine mullite powder, 6-8 parts of fine tabular corundum powder, 4-7 parts of activated SiO2 micro powder, 3-6 parts of α-Al2O3 micro powder, 3-6 parts of kyanite, 2-4 parts of Guangxi white clay, 3-6 parts of CA-70 calcium aluminate cement, and 0.5-1.5 parts of surface-modified stainless steel fiber; S2, the mullite fine powder, the tabular corundum fine powder, the active SiO2 micro powder, the α-Al2O3 micro powder, the kyanite, the Guangxi white clay and the CA-70 calcium aluminate cement are mixed and stirred to obtain a premixed fine powder. S3, after stirring the microporous mullite particles, the alumina hollow spheres and the tabular corundum particles, the premixed fine powder, the surface-modified stainless steel fiber, the explosion-proof fiber and the additive are added in sequence, and stirring is continued for 10 min to 30 min to obtain heat-insulating refractory castable. S4. Add 10% to 15% water to the heat-insulating refractory castable, stir evenly and then pour it into the heat-insulating cover body, and vibrate to compact it to form the inner lining blank. S5, after the inner lining blank is cured at room temperature for 24h~30h, the cured inner lining blank is then baked at 200℃~300℃ for 50h~60h. After baking, the torpedo tanker insulation cover inner lining is obtained.

[0006] Preferably, in step S1, the particle size of the tabular corundum particles is 2mm~3mm; the Al2O3 content in the mullite fine powder is ≥70%, and the particle size is ≤0.074mm; the particle size of the tabular corundum fine powder is ≤0.074mm.

[0007] Preferably, in step S1, the microporous mullite aggregate includes first microporous mullite with a particle size of 5mm~15mm, second microporous mullite with a particle size of 1mm~5mm, and third microporous mullite with a particle size of 0mm~1mm. The first microporous mullite accounts for 40%~50% of the microporous mullite aggregate, the second microporous mullite accounts for 45%~55% of the microporous mullite aggregate, and the third microporous mullite accounts for 3%~5% of the microporous mullite aggregate.

[0008] Preferably, in step S1, the particle size of the kyanite is set to 190 mesh to 210 mesh.

[0009] Preferably, in step S1, the surface modification method of the surface-modified stainless steel fiber is as follows: the steel fiber is first immersed in an aluminum sol with a concentration of 3% to 6% and then dried; then immersed in a silica sol with a concentration of 2% to 3% and dried again to obtain the surface-modified stainless steel fiber.

[0010] Preferably, in step S1, the explosion-proof fiber is a polypropylene fiber, and the length of the explosion-proof fiber is 3mm~5.5mm and the diameter is 25μm~35μm.

[0011] Preferably, in step S1, the additive is a polycarboxylate superplasticizer or a melamine superplasticizer.

[0012] Preferably, a heat-insulating refractory castable is prepared by steps S1 to S3 in the preparation method of the heat-insulating cover liner of the torpedo tanker.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the heat-insulating refractory castable prepared by the present invention and the heat-insulating cover liner of the torpedo tank car prepared based on the heat-insulating refractory castable have comprehensive properties such as lightweight, low thermal conductivity, high strength and long service life. Attached Figure Description

[0014] Figure 1 A schematic flowchart illustrating the preparation method of the insulation cover liner for the torpedo tanker; Figure 2 The image shows the XRD pattern of the heat-insulating refractory castable described in Example 1 after firing at 1400℃ for 3 hours. Figure 3 This is an optical micrograph of the heat-insulating refractory castable described in Example 1 after firing at 1400℃ for 3 hours. Detailed Implementation

[0015] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0016] like Figure 1 As shown, Figure 1 A schematic flowchart illustrating the preparation method of the insulation cover liner for the torpedo tanker.

[0017] The method for preparing the heat-insulating cover liner of the torpedo tanker of the present invention includes the following steps: S1. Prepare raw materials, which include the following components in parts by weight: 100 parts of main material, 0.1-0.3 parts of additives, and 0.1-0.2 parts of explosion-proof fiber; the main material includes the following components in parts by weight: 35-50 parts of microporous mullite particles, 10-15 parts of hollow alumina spheres, 3-5 parts of tabular corundum particles, 12-20 parts of fine mullite powder, 6-8 parts of fine tabular corundum powder, 4-7 parts of activated SiO2 micro powder, 3-6 parts of α-Al2O3 micro powder, 3-6 parts of kyanite, 2-4 parts of Guangxi white clay, 3-6 parts of CA-70 calcium aluminate cement, and 0.5-1.5 parts of surface-modified stainless steel fiber (containing high nickel chromium); S2, the mullite fine powder, the tabular corundum fine powder, the active SiO2 micro powder, the α-Al2O3 micro powder, the kyanite, the Guangxi white clay and the CA-70 calcium aluminate cement are mixed and stirred to obtain a premixed fine powder. S3, after stirring the microporous mullite particles, the alumina hollow spheres and the tabular corundum particles, the premixed fine powder, the surface-modified stainless steel fiber, the explosion-proof fiber and the additive are added in sequence, and stirring is continued for 10 min to 30 min to obtain heat-insulating refractory castable. S4. Add 10% to 15% water to the heat-insulating refractory castable, adjust the flow value to the vibration molding requirements, and inject it into the heat-insulating cover body, then vibrate to compact it to form the inner lining blank. S5, after the inner lining blank is cured at room temperature for 24h~30h, the cured inner lining blank is then baked at 200℃~300℃ for 50h~60h. After baking, the torpedo tanker insulation cover inner lining is obtained.

[0018] Preferably, the particle size of the tabular corundum particles is 2mm~3mm; the Al2O3 content in the mullite fine powder is ≥70%, and the particle size is ≤0.074mm; the particle size of the tabular corundum fine powder is ≤0.074mm.

[0019] Preferably, the microporous mullite aggregate comprises first microporous mullite with a particle size of 5mm to 15mm, second microporous mullite with a particle size of 1mm to 5mm, and third microporous mullite with a particle size of 0mm to 1mm. The first microporous mullite accounts for 40% to 50% of the microporous mullite aggregate, the second microporous mullite accounts for 45% to 55% of the microporous mullite aggregate, and the third microporous mullite accounts for 3% to 5% of the microporous mullite aggregate.

[0020] Preferably, the particle size of the kyanite is set to 190 mesh to 210 mesh.

[0021] Preferably, the surface modification method of the surface-modified stainless steel fiber is as follows: the steel fiber is first immersed in an aluminum sol with a concentration of 3% to 6% and then dried; then immersed in a silica sol with a concentration of 2% to 3% and dried again to obtain the surface-modified stainless steel fiber.

[0022] Preferably, the explosion-proof fiber is a polypropylene fiber, and the length of the explosion-proof fiber is 3mm~5.5mm and the diameter is 25μm~35μm.

[0023] Preferably, the additive is a polycarboxylate superplasticizer or a melamine superplasticizer.

[0024] This invention uses lightweight microporous mullite and alumina hollow spheres as aggregates, laying the foundation for lightweight materials and low thermal conductivity. At the same time, by adding tabular corundum (utilizing its rich active edge surface and asymmetrical shape) and a high-efficiency water-reducing agent (reducing water consumption), the thixotropic properties of the castable are synergistically controlled, so that moisture is directionally discharged during the baking of the molded body, inducing the formation of a large number of closed pores, further reducing the thermal conductivity.

[0025] This invention achieves structural densification and volume compensation simultaneously through high-temperature reaction enhancement—the sintering aid α-Al2O3 micro powder reacts with the hydration products of calcium aluminate cement (CaO∙Al2O3, CaO∙2Al2O3) at service temperature to generate high-melting-point CaO∙6Al2O3; in-situ toughening—the expansion agent kyanite phase transformation and the reaction of α-Al2O3 with active SiO2 to generate needle-like mullite whiskers significantly improve flexural strength and volume compensation; and long-term reinforcement—surface-modified stainless steel fibers form a three-dimensional network support, maintaining the strength stability of the matrix over a long period.

[0026] This invention utilizes active SiO2 micro powder and kyanite, which function as both expansion agents, to generate controllable volume expansion through high-temperature crystal transformation. This precisely counteracts the inherent sintering shrinkage of lightweight castables, improves the high-temperature volume stability of the castable, and completely avoids the risk of crack propagation caused by shrinkage stress.

[0027] The thermally insulating refractory castable prepared using this invention, and the torpedo tank car insulation cover liner prepared based on the thermally insulating refractory castable, possess comprehensive properties such as lightweight, low thermal conductivity, high strength, and long service life. Through precise material composition design and process control, a dual optimization mechanism is achieved: in the low-temperature stage—a large number of closed pores are induced during the low-temperature baking process, significantly reducing the thermal conductivity of the castable; in the high-temperature stage—under high-temperature service conditions, kyanite and active SiO2 undergo crystal transformation and in-situ generate needle-like mullite, which, combined with the synergistic effect of modified stainless steel fibers, simultaneously improves the material's room temperature / high-temperature strength and volume stability. Example 1

[0028] In this embodiment, the raw materials and their contents are as follows: 37 parts of microporous mullite granules, 15 parts of alumina hollow spheres, 4 parts of corundum granules, 14 parts of mullite fine powder, 8 parts of corundum fine powder, 5 parts of activated SiO2 micro powder, 5 parts of α-Al2O3 micro powder, 5 parts of kyanite, 3 parts of Guangxi white clay, 4 parts of calcium aluminate cement, 1 part of modified stainless steel fiber, and 0.1% of polycarboxylate superplasticizer and 0.15% of explosion-proof fiber, accounting for 0.1% of the total amount of the above raw materials.

[0029] The preparation method of the heat insulation cover lining of the torpedo tanker is as follows: First, the raw materials are prepared according to the above-mentioned proportions; then, microporous mullite, alumina hollow spheres and plate-shaped corundum particles are added to a vertical forced mixer and stirred evenly. Then, premixed powder, stainless steel fiber, explosion-proof fiber and additives are added one by one to the rotating mixer. After all the powder is poured in, the mixture is stirred for 30 minutes to obtain the heat insulation refractory castable of the present invention. Then, 10% water is added to the castable and stirred evenly. The castable with suitable fluidity is added to the cover body of the heat insulation cover, and the heat insulation cover refractory castable is vibrated and molded using a vibrator. Finally, the molded blank is cured at room temperature for 24 hours and then baked. After baking, it is put into production.

[0030] The torpedo tanker insulation cover lining prepared in this embodiment, after curing at 110℃ for 2 hours, had an apparent porosity of 35.2% and a bulk density of 1.724 g / cm³. 3 The compressive strength is 21.9 MPa, and the flexural strength is 4.4 MPa. Figure 2 and Figure 3 As shown, Figure 2 The image shows the XRD pattern of the heat-insulating refractory castable described in Example 1 after firing at 1400℃ for 3 hours. Figure 3 The image shows an optical micrograph of the heat-insulating refractory castable described in Example 1 after firing at 1400℃ for 3 hours. After heat treatment at 1400℃ for 3 hours, the compressive strength is 49.5 MPa, the flexural strength is 10.0 MPa, the linear shrinkage rate is 0.075%, and the thermal conductivity is 0.35 W / (m∙K). Example 2

[0031] In this embodiment, the raw materials and their contents are as follows: 45 parts of microporous mullite granules, 11 parts of alumina hollow spheres, 8 parts of corundum granules, 11 parts of fine mullite powder, 6 parts of fine corundum powder, 6 parts of activated SiO2 micro powder, 3 parts of α-Al2O3 micro powder, 4 parts of kyanite, 2 parts of Guangxi white clay, 5 parts of calcium aluminate cement, 1 part of modified stainless steel fiber, and 0.2% of polycarboxylate superplasticizer and 0.2% of explosion-proof fiber, accounting for 0.2% of the total amount of the above raw materials.

[0032] The preparation method of the heat insulation cover liner of the torpedo tanker described in this embodiment is the same as that in Embodiment 1.

[0033] The torpedo tanker insulation cover lining prepared in this embodiment has a compressive strength of 26.2 MPa and a flexural strength of 5.2 MPa after curing at 110 ℃ for 2 hours. After heat treatment at 1400 ℃ for 3 hours, the compressive strength is 45.4 MPa, the flexural strength is 8.7 MPa, the linear shrinkage rate is 0.045%, and the thermal conductivity is 0.45 W / (m∙K). Example 3

[0034] In this embodiment, the raw materials and their contents are as follows: 50 parts of microporous mullite granules, 10 parts of corundum granules, 15 parts of mullite fine powder, 5 parts of corundum fine powder, 8 parts of activated SiO2 micro powder, 2.9 parts of α-Al2O3 micro powder, 3 parts of Guangxi white clay, 5 parts of calcium aluminate cement, 1.0 part of modified stainless steel fiber, 0.1 part of explosion-proof fiber, and 0.15% of melamine water-reducing agent and 0.1% of explosion-proof fiber, accounting for the total amount of the above raw materials.

[0035] The preparation method of the heat insulation cover liner of the torpedo tanker described in this embodiment is the same as that in Embodiment 1.

[0036] The torpedo tank car insulation cover lining prepared in this embodiment has a compressive strength of 25.2 MPa and a flexural strength of 5.8 MPa after curing at 110 ℃ for 2 hours. After heat treatment at 1400 ℃ for 3 hours, the compressive strength is 42.1 MPa, the flexural strength is 9.1 MPa, the linear shrinkage rate is 0.10%, and the thermal conductivity is 0.52 W / (m∙K).

[0037] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A method for preparing an insulating cover liner for a torpedo tanker, characterized in that, Including the following steps: S1. Prepare raw materials, which include the following components in parts by weight: 100 parts of main material, 0.1-0.3 parts of additives, and 0.1-0.2 parts of explosion-proof fiber; the main material includes the following components in parts by weight: 35-50 parts of microporous mullite particles, 10-15 parts of hollow alumina spheres, 3-5 parts of tabular corundum particles, 12-20 parts of fine mullite powder, 6-8 parts of fine tabular corundum powder, 4-7 parts of activated SiO2 micro powder, 3-6 parts of α-Al2O3 micro powder, 3-6 parts of kyanite, 2-4 parts of Guangxi white clay, 3-6 parts of CA-70 calcium aluminate cement, and 0.5-1.5 parts of surface-modified stainless steel fiber; S2, the mullite fine powder, the tabular corundum fine powder, the active SiO2 micro powder, the α-Al2O3 micro powder, the kyanite, the Guangxi white clay and the CA-70 calcium aluminate cement are mixed and stirred to obtain a premixed fine powder; S3, after stirring the microporous mullite particles, the alumina hollow spheres and the tabular corundum particles, the premixed fine powder, the surface-modified stainless steel fiber, the explosion-proof fiber and the additive are added in sequence, and stirring is continued for 10 min to 30 min to obtain heat-insulating refractory castable. S4. Add 10% to 15% water to the heat-insulating refractory castable, stir evenly and then pour it into the heat-insulating cover body, and vibrate to compact it to form the inner lining blank. S5, after the inner lining blank is cured at room temperature for 24h~30h, the cured inner lining blank is then baked at 200℃~300℃ for 50h~60h. After baking, the torpedo tanker insulation cover inner lining is obtained.

2. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the particle size of the tabular corundum particles is 2mm~3mm; the Al2O3 content in the mullite fine powder is ≥70%, and the particle size is ≤0.074mm; the particle size of the tabular corundum fine powder is ≤0.074mm.

3. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the microporous mullite aggregate includes first microporous mullite with a particle size of 5mm to 15mm, second microporous mullite with a particle size of 1mm to 5mm, and third microporous mullite with a particle size of 0mm to 1mm. The first microporous mullite accounts for 40% to 50% of the microporous mullite aggregate, the second microporous mullite accounts for 45% to 55% of the microporous mullite aggregate, and the third microporous mullite accounts for 3% to 5% of the microporous mullite aggregate.

4. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the particle size of the kyanite is set to 190 mesh to 210 mesh.

5. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the surface modification method of the surface-modified stainless steel fiber is as follows: the steel fiber is first immersed in an aluminum sol with a concentration of 3% to 6% and then dried; then immersed in a silica sol with a concentration of 2% to 3% and then dried again to obtain the surface-modified stainless steel fiber.

6. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the explosion-proof fiber is polypropylene fiber, and the length of the explosion-proof fiber is 3mm~5.5mm and the diameter is 25μm~35μm.

7. The method for preparing the heat-insulating cover liner of the torpedo tanker as described in claim 1, characterized in that, In step S1, the additive is a polycarboxylate superplasticizer or a melamine superplasticizer.

8. A heat-insulating refractory castable, characterized in that, It is prepared by using steps S1 to S3 of the preparation method of the heat insulation cover liner of the torpedo tanker as described in any one of claims 1 to 7.

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