Ultra-light high-temperature thermal insulation material

Abstract

The invention belongs to the technical field of refractory materials, and mainly relates to an ultra-light high-temperature thermal insulation material. The ultra-light high-temperature thermal insulation material is prepared from oxides and refractory fibers, and specifically comprises the following components in percentage by weight: 1-3% of fumed silica, 3-4% of fumed alumina, 4-5% of refractory fibers, 3-5% of polymeric aluminum phosphate and 85-90% of polymeric aluminum oxalate. The volume density of the ultra-light thermal insulation material is 0.1 g / cm < 3 > or below, and the highest use temperature is 1500 DEG C. The material is simple in manufacturing process, easy to operate, low in cost and obvious in heat insulation effect, energy conservation and consumption reduction of the high-temperature kiln are effectively guaranteed, and the service life is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials, and mainly relates to an ultra-light high-temperature heat-insulating material. Background Art

[0002] Lightweight insulation materials are mainly used to prevent heat outflow loss under conditions above ambient temperature, and some are used to prevent heat inflow under conditions below ambient temperature. Due to the requirements of energy-saving work, the development of insulation refractory materials is rapid. The volume density of commonly used lightweight insulation materials is 0.6-1.0g / cm 3 For bulk density less than 0.4 g / cm 3 The material is called ultra-lightweight thermal insulation material.

[0003] In the field of refractory material technology, lightweight thermal insulation materials, as an energy-saving material, need to have both a low conductivity coefficient and a high operating temperature to achieve good energy-saving effects; therefore, the characteristics that lightweight thermal insulation materials must possess are: high specific surface area, high porosity, micro-powder-level or even nano-level pores, low bulk density, high strength and operating temperature, no cracking, good stability, and meeting the high-temperature heat treatment process requirements of metals, non-metals and their products; since lightweight thermal insulation materials are porous materials, a large amount of liquid is required during the mixing process, especially for ultra-light high-temperature thermal insulation materials with low bulk density, which are very easy to crack during the drying process, so a supercritical drying process is generally adopted, but this process is complicated and has high production costs, which is not conducive to large-scale production and application. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide an ultra-light high-temperature thermal insulation material.

[0005] The present invention adopts the following technical solutions to achieve the above-mentioned purpose: An ultra-light high-temperature thermal insulation material, characterized in that: the ultra-light high-temperature thermal insulation material uses refractory fiber as a skeleton, uses fumed silica and fumed alumina as fillers, uses polyaluminum phosphate as a binder, and uses polyaluminum oxalate as a burn-off agent to achieve the purpose of controlling the porosity and volume density of the material; the specific raw materials and mass percentages are: Fumed silica 10~15%; Fumed alumina 20~35%; Refractory fiber 10~20%; Polyaluminium phosphate 6~7%; Polyaluminium oxalate 36~48%; The specific production steps are as follows: 1) Treatment of refractory fibers: Mix refractory fibers and water in a ratio of 1:5, stir with an impeller stirrer to disperse the refractory fibers and remove the glass slag in the refractory fibers; collect and dry the treated refractory fibers for later use; 2) Preparation of refractory slurry: First, completely dissolve 6-7% polyaluminum phosphate and 36-48% polyaluminum oxalate in 400-500% water, then add 10-20% refractory fiber, stir for 10-15 minutes, and finally add 10-15% fumed silica and 20-35% fumed alumina, stir well to obtain slurry; let stand for 15-20 hours; 3) Drying and firing: Keep the prepared slurry at 110-130°C for 2-3 days to retain 35-40% of its moisture; then move it to a microwave drying oven and keep it at 80°C for 10-15 hours to obtain a primary body with a porosity of 60-65%; finally, fire the primary body at 1200-1250°C for 2-3 hours, and after cooling, it becomes an ultra-light high-temperature insulation material.

[0006] The ultra-light high-temperature thermal insulation material consists of 2-3% by volume of silicon dioxide, 6-9% by volume of aluminum oxide, 1.2-1.4% by volume of aluminum phosphate, 2-4% by volume of refractory fibers and 84-89% by volume of pores.

[0007] The particle size of the refractory fiber is 0.5-2 μm, and the chemical composition w (Al2O3+SiO2) is greater than 99.0%, and w (Al2O3) is greater than 70.0%.

[0008] The present invention proposes an ultra-light high-temperature thermal insulation material, which uses refractory fiber as a skeleton, gas-phase white carbon black and gas-phase alumina as fillers, polyaluminum phosphate as a binder, and polyaluminum oxalate as a burn-off agent to achieve the purpose of controlling the porosity and volume density of the material; the initial mud material of the present invention is an oil-water mixture. When the moisture is retained to less than 40%, the moisture exists in the form of oil-in-water, and the surface tension is very large. Conventional baking is difficult to remove the moisture and easily causes the material to collapse. During microwave baking, the material is heated evenly and a large steam pressure is formed inside, which avoids the shrinkage of the material. When drying is completed, the material also has a certain strength and can well complete the moving and handling work; the final firing completes the volatilization of the organic components and retains enough space holes, so that the material has the characteristics of high temperature resistance and low density. DETAILED DESCRIPTION The present invention takes ultra-light high-temperature thermal insulation materials of different densities as examples to illustrate their actual performance. Embodiment 1:

[0009] First, the refractory fiber and water are mixed in a ratio of 1:5, and stirred with an impeller stirrer to disperse the refractory fiber and remove the slag; the treated refractory fiber is collected and dried for later use; Dissolve 7% polyaluminium phosphate and 48% polyaluminium oxalate completely in 500% water, then add 18% refractory fibre, stir for 10-15 minutes, finally add 10% fumed silica and 17% fumed alumina, stir well, and let stand for 15 hours; Keep the prepared slurry at 110-130℃ for 2-3 days to keep its moisture content at 35-40%. Then move it to a microwave drying oven and keep it at 80℃ for 10-15 hours. When the porosity reaches 60-65%, it is used as a primary body. Sinter the primary body at 1200-1250℃, keep it for 2-3 hours, and after cooling, the volume density is 0.12-0.17g / cm 3 , an ultra-lightweight high-temperature insulation material with a thermal conductivity of 0.028 to 0.035 W / (m•K). Embodiment 2:

[0010] First, the refractory fibers and water are mixed in a ratio of 1:5, and stirred with an impeller stirrer to disperse the refractory fibers and remove the slag; the treated refractory fibers are collected and dried for later use.

[0011] Dissolve 6.5% polyaluminium phosphate and 42% polyaluminium oxalate completely in 400-500% water, then add 15% refractory fibre, stir for 10-15 minutes, finally add 13% fumed silica and 23.5% fumed alumina, stir well, and let stand for 13 hours; The prepared slurry is kept at 110-130°C for 2-3 days to retain 35-40% of its moisture; then it is moved to a microwave drying oven and kept at 80°C for 10-15 hours. When the porosity reaches 60-65%, it is used as a primary body; the primary body is fired at 1200-1250°C and kept for 2-3 hours. After cooling, the bulk density is 0.15-0.21 g / cm 3 , an ultra-lightweight high-temperature insulation material with a thermal conductivity of 0.032 to 0.039 W / (m•K). Embodiment 3:

[0012] First, the refractory fiber and water are mixed in a ratio of 1:5, and stirred with an impeller stirrer to disperse the refractory fiber and remove the slag; the treated refractory fiber is collected and dried for later use; Dissolve 6% polyaluminium phosphate and 36% polyaluminium oxalate completely in 400-500% water, then add 10% refractory fibre, stir for 10-15 minutes, finally add 15% fumed silica and 33% fumed alumina, stir well, and let stand for 10 hours; The prepared slurry is kept at 110-130°C for 2-3 days to retain 35-40% of its moisture; then it is moved to a microwave drying oven and kept at 80°C for 10-15 hours. When the porosity reaches 60-65%, it is used as a primary body; the primary body is fired at 1200-1250°C and kept for 2-3 hours. After cooling, it becomes an ultra-light high-temperature insulation material with a volume density of 0.19-0.26 g / cm3 and a thermal conductivity of 0.037-0.052 W / (m•K).

Claims

1. An ultra-light high-temperature thermal insulation material, characterized in that: The ultra-lightweight high-temperature thermal insulation material uses refractory fiber as the skeleton, fumed silica and fumed alumina as fillers, polyaluminum phosphate as a binder, and polyaluminum oxalate as a burn-off agent to achieve the purpose of controlling the porosity and volume density of the material; the specific raw materials and mass percentages are: Fumed silica 10~15%; Fumed alumina 20~35%; Refractory fiber 10~20%; Polyaluminium phosphate 6~7%; Polyaluminium oxalate 36~48%; The specific production steps are as follows: 1) Treatment of refractory fibers: Mix refractory fibers and water in a ratio of 1:5, stir with an impeller stirrer to disperse the refractory fibers and remove the glass slag in the refractory fibers; collect and dry the treated refractory fibers for later use; 2) Preparation of refractory slurry: First, completely dissolve 6-7% polyaluminum phosphate and 36-48% polyaluminum oxalate in 400-500% water, then add 10-20% refractory fiber, stir for 10-15 minutes, and finally add 10-15% fumed silica and 20-35% fumed alumina, stir well to obtain slurry; let stand for 15-20 hours; 3) Drying and firing: The prepared slurry is kept at 110-130°C for 2-3 days to retain 35-40% of its moisture; then it is moved to a microwave drying oven and kept at 80°C for 10-15 hours to obtain a primary body with a porosity of 60-65%; finally, the primary body is fired at 1200-1250°C for 2-3 hours, and after cooling, it becomes an ultra-light high-temperature thermal insulation material; The ultra-light high-temperature thermal insulation material consists of 2-3% by volume of silicon dioxide, 6-9% by volume of aluminum oxide, 1.2-1.4% by volume of aluminum phosphate, 2-4% by volume of refractory fibers and 84-89% by volume of pores.

2. The ultra-light high-temperature thermal insulation material according to claim 1, characterized in that The particle size of the refractory fiber is 0.5-2 μm, and the chemical composition w (Al2O3+SiO2) is greater than 99.0%, and w (Al2O3) is greater than 70.0%.