A microporous refractory insulating material and a method for its production

Abstract

The application belongs to the technical field of heat-insulating materials, and discloses a microporous fire-resistant heat-insulating material and a preparation method thereof.The microporous fire-resistant heat-insulating material comprises the following components in percentage by mass: 50-85% of fumed silica, 10-40% of inorganic additives and 1-10% of inorganic fibers; the inorganic additives comprise zirconium silicate with a purity of 40-58%, and the mass percentage of zirconium silicate in the inorganic additives is 30-70%; and the specific surface area of the fumed silica is 150-250 m 2 / g. The microporous fire-resistant heat-insulating material provided by the application has excellent high-temperature resistance and heat preservation performance, and the thermal conductivity coefficient thereof is less than 0.036 / W / (m·K) at 800 DEG C, and the permanent linear change after heating for 960 DEG C / 24h is less than 1.60%. Moreover, the microporous fire-resistant heat-insulating material provided by the application does not add nano-alumina, and the cost thereof can be reduced by more than 15%, and the market acceptance is high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thermal insulation materials, and particularly relates to a microporous refractory thermal insulation material and a preparation method thereof. BACKGROUND

[0002] The refractory thermal insulation material is applied to various fields of the national economy such as steel, non-ferrous metal, glass, cement, ceramics, petrochemical, machinery, boiler, light industry, electric power, military industry, etc., is an essential basic material for guaranteeing the production operation and technical development of various industries, and plays an irreplaceable important role in the development of high-temperature industrial production. In the high-temperature industries such as metallurgical high-temperature equipment, petrochemical cracking furnace, building material industrial kiln and environmental protection (power generation) incinerator, in order to achieve the goal of energy saving and cost reduction, it is necessary to improve the thermal insulation performance of the equipment to reduce energy consumption and save energy cost. However, with the continuous improvement of energy saving requirements, the traditional thermal insulation material has been unable to meet the needs of high efficiency, low carbon and energy saving.

[0003] The microporous thermal insulation material commonly used at present which can withstand a temperature of 900 DEG C and above for a long time usually adds nano alumina as high-temperature refractory micropowder. If the microporous thermal insulation material lacks the refractory micropowder substance mainly composed of nano alumina, although it can still maintain excellent thermal insulation performance, it cannot be used at a high temperature of 800 DEG C-1250 DEG C for a long time. When used at a high temperature for a long time, gaps will inevitably occur at the joint, reducing the overall thermal insulation performance of the thermal insulation layer. However, due to the high price of nano alumina, the cost of the refractory thermal insulation material is relatively high, and the market acceptance is relatively low. Therefore, it is of great significance to the development of high-temperature industries to research a refractory thermal insulation material which has excellent high-temperature resistance, low cost and high market acceptance. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a microporous refractory thermal insulation material and a preparation method thereof. The microporous refractory thermal insulation material provided by the present application not only has excellent high-temperature resistance and thermal insulation performance, but also can effectively reduce the cost.

[0005] The present application provides a microporous refractory thermal insulation material.

[0006] Specifically, a microporous refractory thermal insulation material comprises the following components in terms of mass percentage:

[0007] 50%-85% of fumed silica, 10%-40% of inorganic additives and 1%-10% of inorganic fibers;

[0008] The inorganic additive comprises zirconium silicate, the mass percentage of the zirconium silicate in the inorganic additive is 40%-70%, the content of Zr(Hf)O2 in the zirconium silicate is 40%-58%, and the content of AlO is 1%-8%;

[0009] The specific surface area of the fumed silica is 150-250 m 2 / g.

[0010] Preferably, the specific surface area of the fumed silica is 150-200 m 2 / g.

[0011] Preferably, the purity of the zirconium silicate is 45%-55%.

[0012] Preferably, the microporous refractory thermal insulation material further comprises microsilica powder. The main component of the microsilica powder is silicon dioxide, and it also contains impurities such as sodium oxide, calcium oxide, magnesium oxide, iron oxide, and aluminum oxide. By replacing part of the fumed silica with microsilica powder, not only can the high-temperature resistance (900℃ and above) of the microporous refractory thermal insulation material be improved, but also the heating permanent linear change rate of the material can be reduced. Moreover, because the price of microsilica powder is much lower than that of fumed silica, the cost of the material can be reduced.

[0013] Preferably, the mass of the microsilica powder accounts for 5%-20% of the fumed silica; further preferably, the mass of the microsilica powder accounts for 5%-10% of the fumed silica.

[0014] Preferably, the particle size of the microsilica powder is 0.1-5.5μm.

[0015] Preferably, the inorganic additive further comprises at least one of silicon carbide, zirconium silicate powder, iron oxide, diatomite, or titanium dioxide; further preferably, the inorganic additive further comprises at least one of silicon carbide, zirconium silicate powder, or titanium dioxide.

[0016] Preferably, the purity of the silicon carbide is ≥90%, and the particle size of the silicon carbide is 1-10μm.

[0017] Preferably, the particle size of the zirconium silicate powder is less than 10μm.

[0018] Preferably, the particle size of the iron oxide is less than 45μm.

[0019] Preferably, the particle size of the diatomite is less than 45μm.

[0020] Preferably, the particle size of the titanium dioxide is less than 15μm.

[0021] Preferably, the microporous refractory thermal insulation material comprises the following components by mass percentage: 54%-75% fumed silica, 20%-45% inorganic additives, and 1%-6% inorganic fibers; further preferably, the microporous refractory thermal insulation material comprises the following components by mass percentage: 60%-70% fumed silica, 25%-38% inorganic additives, and 2%-6% inorganic fibers.

[0022] Preferably, the zirconium silicate accounts for 45%-65% of the mass percentage of the inorganic additives; further preferably, the zirconium silicate accounts for 50%-60% of the mass percentage of the inorganic additives.

[0023] Preferably, the particle size of the zirconium silicate is less than 10 μm.

[0024] Preferably, the content of Zr(Hf)O2 in the zirconium silicate is 40%-58%, the content of AlO is 1%-8%, the content of SiO2 is 25%-40%, the content of TiO2 is 0.5-8%, and the content of Fe2O3 is 0.5-5%; further preferably, the content of Zr(Hf)O2 in the zirconium silicate is 45%-55%, the content of AlO is 2%-8%, the content of SiO2 is 25%-38%, the content of TiO2 is 0.5-8%, and the content of Fe2O3 is 1-4%. More preferably, the content of Zr(Hf)O2 in the zirconium silicate is 50%, the content of AlO is 6%, the content of SiO2 is 35%, the content of TiO2 is 6%, and the content of Fe2O3 is 3%.

[0025] Preferably, the inorganic fibers comprise at least one of glass fibers, basalt fibers, high-silica fibers, and ceramic fibers.

[0026] Preferably, the diameter of the inorganic fibers is 1-30 μm; further preferably, the diameter of the inorganic fibers is 3-25 μm.

[0027] Preferably, the inorganic fibers have a weight loss of 2%-10% after being dried at 105°C.

[0028] The application also provides a preparation method of a microporous refractory thermal insulation material.

[0029] Specifically, the preparation method of the microporous refractory thermal insulation material comprises the following steps:

[0030] The components are mixed and pressed to obtain the microporous refractory thermal insulation material.

[0031] Preferably, the linear speed of the mixing is 36-53 m / s; and the mixing time is 5-15 min.

[0032] More specifically, a method for preparing a microporous refractory thermal insulation material, comprising the following steps: weighing fumed silica, inorganic additives and inorganic fibers, then conveying them into a mixer, mixing at a linear speed of 36-53 m / s for 5-15 min, and then conveying them into a hydraulic forming device for pressing to obtain the microporous refractory thermal insulation material.

[0033] The research finds that, by taking fumed silica and inorganic additives containing zirconium silicate as main components, and by controlling the specific surface area of the fumed silica to be 150-250 m 2 / g (especially 150-200 m 2 / g), the high-temperature resistance of the material can be effectively improved, and the permanent linear change rate of the microporous refractory thermal insulation material after heating can be greatly reduced; meanwhile, by taking zirconium silicate as the main inorganic additive, and by controlling the purity of the zirconium silicate, the high-temperature resistance of the material can be further improved, and the permanent linear change rate of the material after heating can be reduced. The zirconium silicate contains Zr(Hf)O2, AIO, and impurities such as SiO2, TiO2 and Fe2O3, and the doped aluminum trioxide, iron trioxide and titanium dioxide can act as infrared light shielding agents to improve the heat resistance of the material. The research finds that, when the content of Zr(Hf)O2 in the zirconium silicate is controlled to be 40%-58% and the content of AIO is controlled to be 1%-8%, the heat resistance of the material can be optimized; when the content of Zr(Hf)O2 in the zirconium silicate is more than 60% or less than 40%, the other impurities change greatly and cannot play a synergistic effect with Zr(Hf)O2 in improving the heat resistance of the material, and the permanent linear change rate of the prepared microporous refractory thermal insulation material after heating will obviously increase.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] (1) The microporous refractory thermal insulation material provided by the present application takes fumed silica and inorganic additives containing zirconium silicate as main components, and inorganic fibers are used in combination; and by controlling the purity of the zirconium silicate and the specific surface area of the fumed silica, a microporous refractory thermal insulation material with excellent high-temperature resistance and heat preservation performance can be prepared; and the microporous refractory thermal insulation material provided by the present application uses zirconium silicate with a purity of 40%-58% to replace nano-aluminum oxide, which can effectively reduce the cost of the thermal insulation material and improve the market acceptability.

[0036] (2) The microporous refractory thermal insulation material provided by the present application has a thermal conductivity coefficient of less than 0.036 / W / (m·K) at 800℃, a permanent linear change after heating of less than 1.60% at 960℃ / 24h, and a permanent linear change after heating of less than 2.00% at 1200℃ / 8h. Compared with the refractory thermal insulation material added with nano-aluminum oxide, the microporous refractory thermal insulation material provided by the present application can reduce the cost by more than 15%, and has high market acceptability. DETAILED DESCRIPTION

[0037] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be noted that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0038] The raw materials, reagents or devices used in the following examples, if not specifically stated, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0039] Example 1

[0040] A microporous refractory thermal insulation material, comprising the following components by mass percentage: 65% fumed silica, 4% microsilica, 14% zirconium silicate, 14% silicon carbide, 1% glass fiber and 2% basalt fiber;

[0041] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the microsilica is 0.1-3 μm; the zirconium silicate contains Zr(Hf)O2 50%, SiO2 35%, AIO 6%, TiO2 6%, Fe2O3 3%, and the particle size of the zirconium silicate is less than 6 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0042] The preparation method of the microporous refractory thermal insulation material comprises the following steps: weighing the fumed silica, the microsilica, the zirconium silicate, the silicon carbide, the glass fiber and the basalt fiber, then conveying them into a high-speed mixer, mixing them at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous refractory thermal insulation material.

[0043] Example 2

[0044] A microporous refractory thermal insulation material, comprising the following components by mass percentage: 65% fumed silica, 4% microsilica, 18% zirconium silicate, 10% silicon carbide, 1% glass fiber and 2% basalt fiber;

[0045] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the microsilica is 0.1-3 μm; the zirconium silicate contains Zr(Hf)O2 50%, SiO2 35%, AIO 6%, TiO2 6%, Fe2O3 3%, and the particle size of the zirconium silicate is less than 6 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0046] The preparation method of the microporous fire-resistant and heat-insulating material comprises the following steps: weighing the fumed silica, microsilica powder, zirconium silicate, silicon carbide, glass fiber and basalt fiber, then conveying them into a high-speed mixer, mixing at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous fire-resistant and heat-insulating material.

[0047] Example 3

[0048] The microporous fire-resistant and heat-insulating material comprises the following components in percentage by mass: 65% of fumed silica, 4% of microsilica powder, 14% of zirconium silicate, 14% of titanium dioxide, 1% of glass fiber and 2% of basalt fiber.

[0049] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the microsilica powder is 0.1-3 μm; the zirconium silicate contains Zr(Hf)O2 50%, SiO2 35%, AIO 6%, TiO2 6% and Fe2O3 3%, and the particle size of the zirconium silicate is less than 6 μm; the particle size of the titanium dioxide is 5-10 μm; and the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0050] The preparation method of the microporous fire-resistant and heat-insulating material comprises the following steps: weighing the fumed silica, microsilica powder, zirconium silicate, silicon carbide, glass fiber and basalt fiber, then conveying them into a high-speed mixer, mixing at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous fire-resistant and heat-insulating material.

[0051] Example 4

[0052] The microporous fire-resistant and heat-insulating material comprises the following components in percentage by mass: 57% of fumed silica, 12% of microsilica powder, 14% of zirconium silicate, 14% of silicon carbide, 1% of glass fiber and 2% of basalt fiber.

[0053] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the microsilica powder is 0.1-3 μm; the zirconium silicate contains Zr(Hf)O2 50%, SiO2 35%, AIO 6%, TiO2 6% and Fe2O3 3%, and the particle size of the zirconium silicate is less than 6 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; and the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0054] The preparation method of the microporous fire-resistant and heat-insulating material comprises the following steps: weighing the fumed silica, microsilica powder, zirconium silicate, silicon carbide, glass fiber and basalt fiber, then conveying them into a high-speed mixer, mixing at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous fire-resistant and heat-insulating material.

[0055] Comparative Example 1

[0056] A microporous fire-resistant and heat-insulating material comprises the following components in percentage by mass: 61% of fumed silica, 4% of microsilica powder, 14% of zirconium silicate, 18% of silicon carbide, 1% of glass fiber and 2% of basalt fiber.

[0057] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the zirconium silicate is 2-8 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0058] The preparation method of the microporous fire-resistant and heat-insulating material comprises the following steps: weighing the fumed silica, microsilica powder, zirconium silicate, silicon carbide, glass fiber and basalt fiber, then conveying them into a high-speed mixer, mixing at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous fire-resistant and heat-insulating material.

[0059] Comparative Example 2

[0060] A microporous fire-resistant and heat-insulating material comprises the following components in percentage by mass: 65% of fumed silica, 4% of microsilica powder, 14% of zirconium silicate, 14% of silicon carbide, 1% of glass fiber and 2% of basalt fiber.

[0061] The specific surface area of the fumed silica is 150-200 m 2 / g; the particle size of the zirconium silicate is 2-8 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0062] The preparation method of the microporous fire-resistant and heat-insulating material comprises the following steps: weighing the fumed silica, microsilica powder, zirconium silicate, silicon carbide, glass fiber and basalt fiber, then conveying them into a high-speed mixer, mixing at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous fire-resistant and heat-insulating material.

[0063] Comparative Example 3

[0064] A microporous refractory thermal insulation material, comprising the following components by mass percentage: 65% fumed silica, 4% microsilica, 14% zirconium silicate, 14% silicon carbide, 1% glass fiber and 2% basalt fiber;

[0065] The specific surface area of the fumed silica is 250-300 m 2 / g; the particle size of the microsilica is 0.1-3 μm; the zirconium silicate contains Zr(Hf)O2 50%, SiO2 35%, AlO 6%, TiO2 6% and Fe2O3 3%, and the particle size of the zirconium silicate is less than 6 μm; the purity of the silicon carbide is 95%, and the particle size of the silicon carbide is 2-8 μm; the diameters of the glass fiber and the basalt fiber are 3-20 μm.

[0066] The preparation method of the microporous refractory thermal insulation material comprises the following steps: weighing the fumed silica, the microsilica, the zirconium silicate, the silicon carbide, the glass fiber and the basalt fiber, then conveying them into a high-speed mixer, mixing them at a linear speed of 45 m / s for 10 min, and then conveying them into a hydraulic forming equipment for pressing to obtain the microporous refractory thermal insulation material.

[0067] The microporous refractory thermal insulation materials prepared in Examples 1-4 and Comparative Examples 1-3 are subjected to performance detection, and the detection items include the thermal conductivity coefficient at 800℃, the heating permanent linear change at 960℃ / 24h and the heating permanent linear change at 1200℃ / 8h. The test method refers to GB / T 17911-2018. The test results are shown in Table 1.

[0068] Table 1

[0069]

[0070] As shown in Table 1, the high-temperature resistance and thermal insulation performance of the microporous refractory thermal insulation material prepared in the examples of the present application are obviously better than those of the comparative examples.

[0071] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A microporous refractory insulating material, characterized in that, According to the mass percentage, the following components are included: 50%-85% fumed silica, 10%-40% inorganic additive, and 1%-10% inorganic fiber; The inorganic additive includes zirconium silicate, the mass percentage of the zirconium silicate in the inorganic additive is 40%-70%, the content of Zr(Hf)O2 in the zirconium silicate is 40%-58%, and the content of Al2O3 is 1%-8%. The specific surface area of the fumed silica is 150-250 m 2 / g.

2. The microporous refractory insulating material of claim 1, wherein, The specific surface area of the fumed silica is 150-200 m 2 / g.

3. The microporous refractory thermal insulating material according to claim 1 or 2, characterized in that, The microporous refractory insulation material further includes microsilica powder, and the mass of the microsilica powder accounts for 5%-20% of the fumed silica.

4. The microporous fire resistant thermal insulation material according to claim 1 or 2, characterized in that, The inorganic additive further includes at least one of silicon carbide, zirconium silicate powder, iron oxide, diatomite, or titanium dioxide.

5. The microporous fire resistant insulating material of claim 4, wherein, The purity of the silicon carbide is ≥90%, and the particle size of the silicon carbide is 1-10 μm; the particle size of the zirconium silicate powder is less than 10 μm.

6. The microporous fire resistant thermal insulation material of claim 1 or 2, wherein, According to the mass percentage, the microporous refractory insulation material includes the following components: 54%-75% fumed silica, 20%-45% inorganic additive, and 1%-6% inorganic fiber.

7. The microporous fire resistant insulating material of claim 6, wherein, According to the mass percentage, the microporous refractory insulation material includes the following components: 60%-70% fumed silica, 25%-38% inorganic additive, and 2%-6% inorganic fiber.

8. The microporous fire resistant insulating material of claim 7, wherein, The mass percentage of the zirconium silicate in the inorganic additive is 45%-65%.

9. The microporous fire resistant thermal insulation material of claim 1 or 2, wherein, The inorganic fiber includes at least one of glass fiber, basalt fiber, high-silica fiber, and ceramic fiber.

10. A method for preparing the microporous refractory insulation material according to any one of claims 1-9, comprising the following steps: Mixing the components, pressing, and obtaining the microporous refractory insulation material.

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