阅读说明：本技术 一种高温管道系统用低导热耐火材料及其制备方法 (Low-heat-conductivity refractory material for high-temperature pipeline system and preparation method thereof ) 是由 董红芹 樊效乐 李建涛 于 2021-09-13 设计创作，主要内容包括：本发明涉及一种高温管道系统用低导热耐火材料及其制备方法,所述耐火材料可选自包括以质量分数计的如下组分：10％～30％的微孔烧结刚玉、10％～15％的莫来石、10％～45％的红柱石、30％～36％的红柱石粉、4％～10％的氢氧化铝。该耐火材料以红柱石作为主材料,充分利用红柱石是网状的莫来石中间夹杂高纯石英相的微观结构,有利于降低导热；此外采用具有微孔结构的微孔烧结刚玉为部分原料,并搭配微米级氢氧化铝,利用氢氧化铝高温气相挥发留下空隙,营造微孔效果,从而降低耐火材料的导热性并提高抗热震稳定性。(The invention relates to a low-heat-conductivity refractory material for a high-temperature pipeline system and a preparation method thereof, wherein the refractory material can be selected from the following components in parts by mass: 10 to 30 percent of micropore sintering corundum, 10 to 15 percent of mullite, 10 to 45 percent of andalusite, 30 to 36 percent of andalusite powder and 4 to 10 percent of aluminum hydroxide. The refractory material takes andalusite as a main material, fully utilizes the microstructure that the andalusite is reticular mullite and is mixed with high-purity quartz phase in the middle, and is beneficial to reducing heat conduction; in addition, the microporous sintered corundum with a microporous structure is used as a part of raw materials, micron-sized aluminum hydroxide is matched, and gaps are left by utilizing high-temperature gas-phase volatilization of the aluminum hydroxide to create a microporous effect, so that the heat conductivity of the refractory material is reduced, and the thermal shock resistance is improved.)

1. A low-heat-conductivity refractory material for high-temperature pipeline systems is characterized by being selected from the following components in percentage by mass: 10 to 30 percent of micropore sintering corundum, 10 to 15 percent of mullite, 10 to 45 percent of andalusite, 30 to 36 percent of andalusite powder and 4 to 10 percent of aluminum hydroxide.

2. The refractory of claim 1, wherein the microporous sintered corundum includes not less than 99% by mass Al₂O₃And Fe with the mass content not higher than 0.1%₂O₃The apparent porosity of the micropore sintered corundum is less than or equal to 5 percent, and the closed porosity is more than or equal to 6 percent.

3. The refractory of claim 1, wherein the mullite includes not less than 72% Al by mass₂O₃And Fe with the mass content not higher than 0.5%₂O₃The mass content of the mullite is more than or equal to 92 percent.

4. The refractory according to claim 1, wherein the andalusite and andalusite powders each include Al in an amount of not less than 57% by mass₂O₃And Fe with a mass content of not more than 1%₂O₃。

5. The refractory according to claim 2, wherein the 10% to 30% of the microporous sintered corundum includes 10% to 20% of microporous sintered corundum having a particle size distribution of 1 to 3mm and 0% to 10% of microporous sintered corundum having a particle size of 1mm or less.

6. The refractory of claim 3, wherein the mullite has a particle size distribution of 1 to 3 mm.

7. The refractory according to claim 4, wherein the 10% to 45% andalusite comprises 10% to 30% andalusite having a particle size distribution of 1 to 3mm and 0% to 15% andalusite having a particle size of 1mm or less, and the andalusite powder has a particle size of 0.08mm or less.

8. The refractory of any one of claims 1 to 7, wherein the aluminum hydroxide has a particle size of 5 μm or less.

9. The preparation method of the low-heat-conductivity refractory material for the high-temperature pipeline system as claimed in any one of claims 1 to 8, wherein the preparation method comprises the following process steps of feeding, dry mixing, adding aluminum dihydrogen phosphate with the mass fraction of 4-6%, uniformly mixing, punch forming, drying and sintering.

10. The preparation method according to claim 9, wherein the drying process comprises drying at a temperature of 80-120 ℃ for 24-48 h, and the firing process comprises maintaining at 1450 ℃ for 12 h.

Technical Field

The invention relates to the technical field of refractory material preparation, in particular to a low-heat-conductivity refractory material for a high-temperature pipeline system and a preparation method thereof.

Background

Common high-temperature pipelines, such as blast furnace hot blast stove pipelines, generally adopt heavy aluminum silicon series refractory materials, such as corundum mullite bricks, corundum andalusite bricks, sillimanite bricks and the like, and the lower the porosity, the better the bulk density and the higher the porosity in the design and quality control of the materials. The low porosity and high compactness are favorable for high temperature resistance, but do not have low heat conduction performance and are not favorable for heat preservation; the higher the temperature is, the more obvious the influence of the thermal conductivity on the temperature drop is, so the significance of reducing the thermal conductivity of the working lining on the premise of not reducing the high-temperature performance is great.

The heat conductivity of the refractory material is closely related to the composition, porosity and the like of the refractory material. The pipeline without slag resistance requirement is distributed between the blast furnace and the hot blast stove, the length of the pipeline is about 50-80 m, the load is not high, but the hot blast is conveyed in a long distance, so that the pipeline has good heat insulation performance, temperature fluctuation can occur under normal working conditions, and certain thermal shock resistance stability is required.

Based on the special requirement of a high-temperature pipeline on a refractory material, the invention provides the refractory material which is suitable for the working condition and has low thermal conductivity and high thermal shock resistance stability, and is also suitable for a high-temperature furnace lining which is not contacted with a melt.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a low-heat-conduction refractory material for a high-temperature pipeline system and a preparation method thereof.

In order to achieve the above purpose, the technical scheme adopted by the invention comprises the following steps:

according to a first aspect of the present invention, a low thermal conductivity refractory for high temperature piping systems is disclosed, said refractory being selected from the group consisting of: 10 to 30 percent of micropore sintering corundum, 10 to 15 percent of mullite, 10 to 45 percent of andalusite, 30 to 36 percent of andalusite powder and 4 to 10 percent of aluminum hydroxide.

Further, the microporous sintered corundum preferably includes Al in an amount of not less than 99% by mass₂O₃And Fe with the mass content not higher than 0.1%₂O₃The apparent porosity of the micropore sintered corundum is less than or equal to 5 percent, and the closed porosity is more than or equal to 6 percent.

Further, the mullite preferably comprises not less than 72 percent of mass contentAl of (2)₂O₃And Fe with the mass content not higher than 0.5%₂O₃The mass content of the mullite phase of the mullite is more than or equal to 92 percent.

Further, the andalusite and the andalusite powder preferably include Al in a mass content of not less than 57%, respectively₂O₃And Fe with a mass content of not more than 1%₂O₃。

Further, the 10-30% of microporous sintered corundum preferably comprises 10-20% of microporous sintered corundum with particle size distribution of 1-3 mm and 0-10% of microporous sintered corundum with particle size less than or equal to 1 mm.

Furthermore, the particle size distribution of the mullite is preferably 1-3 mm.

Further, the 10% -45% of andalusite preferably comprises 10% -30% of andalusite with the particle size distribution of 1-3 mm and 0% -15% of andalusite with the particle size of less than or equal to 1mm, and the particle size of andalusite powder is preferably less than or equal to 0.08 mm.

Further, the particle size of the aluminum hydroxide is preferably 5 μm or less.

According to the second aspect of the invention, the preparation method of the low-heat-conductivity refractory material for the high-temperature pipeline system comprises the following process steps of feeding, dry mixing, adding aluminum dihydrogen phosphate with the mass fraction of 4-6%, uniformly mixing, punch forming, drying and sintering.

Further, the drying process preferably comprises drying for 24-48 hours at a temperature range of 80-120 ℃, and the firing process preferably comprises heat preservation for 12 hours at 1450 ℃.

The invention has the beneficial effects that:

the low-heat-conduction refractory material for the high-temperature pipeline system takes andalusite as a main material, adopts homologous multiphase composition, fully utilizes the microstructure that the andalusite is reticular mullite and is mixed with high-purity quartz phase in the middle, and is beneficial to reducing heat conduction; in addition, the microporous sintered corundum with a microporous structure is used as a part of raw materials, micron-sized aluminum hydroxide is matched, and gaps are left by utilizing high-temperature gas-phase volatilization of the aluminum hydroxide to create a microporous effect, so that the heat conductivity of the refractory material is reduced, and the thermal shock resistance is improved.

Detailed Description

Research shows that the more compact the refractory material is, the better the refractory material is, and some properties of the refractory material are in a balance, for example, the lower the porosity of the material is, the more compact the material is, the poorer the thermal shock resistance of the material is, and the higher the thermal conductivity of the material is. According to the invention, firstly, a material with low thermal conductivity is selected on the basis of a thermal conduction principle, and then micropores are created in a material matrix, so that the thermal shock resistance stability of the material is improved and the thermal conductivity of the material is reduced under the conditions that the material is not changed and the high-temperature performance is not reduced, thereby improving the energy-saving effect.

The technical principle of the invention is as follows: the thermal conductivity of a material is closely related to the phase composition, phase distribution, and in particular the porosity. The higher the silicon content, the higher the porosity, and the lower the thermal conductivity of the aluminum-silicon-based refractory material, and this is related to the structure of the material. The thermal conductivity of the material, typically single crystalline, is less than that of polycrystalline; the more complex the structure of the material, the lower the thermal conductivity of the material; air has a low thermal conductivity relative to solids, and thus, porosity can significantly reduce the thermal conductivity of a material. According to the principles, the andalusite is selected as the main material firstly, and the microstructure of the andalusite is that a high-purity quartz phase is mixed in the middle of reticular mullite, so that the heat conduction is reduced; in addition, microporous sintered corundum with a microporous structure is used as part of raw materials, and during the burdening process, the matrix and the aggregate are not made of single-phase materials, and homologous multiphase mixed raw materials are used; the most important is that micron aluminum hydroxide is added, and gaps are left by utilizing high-temperature gas phase volatilization of the micron aluminum hydroxide, so that micropores are created, the heat conduction is reduced, and the thermal shock stability is improved.

For a clearer understanding of the contents of the present invention, reference will be made to the following examples.

Example 1

A low-heat-conductivity refractory material for high-temperature pipeline systems is selected from the following components in percentage by mass: 10% of microporous sintered corundum, 10% of mullite, 40% of andalusite, 36% of andalusite powder and 4% of aluminum hydroxide. Wherein the micropore firingThe corundum has a grain size distribution of 1-3 mm and contains Al with a mass content of not less than 99%₂O₃And Fe with the mass content not higher than 0.1%₂O₃The apparent porosity of the micropore sintered corundum is less than or equal to 5 percent, and the closed porosity is more than or equal to 6 percent; the mullite has the particle size distribution of 1-3 mm and contains Al with the mass content not less than 72%₂O₃And Fe with the mass content not higher than 0.5%₂O₃And the mass content of the mullite is more than or equal to 92 percent; the andalusite comprises 25% of andalusite with the particle size distribution of 1-3 mm and 15% of andalusite with the particle size of less than or equal to 1mm, the granularity of andalusite powder is less than or equal to 0.08mm, and the andalusite powder respectively comprise Al with the mass content of not less than 57%₂O₃And Fe with a mass content of not more than 1%₂O₃(ii) a The particle size of the aluminum hydroxide is less than or equal to 5 microns.

Preferably, the preparation method of the low-heat-conductivity refractory material for the high-temperature pipeline system comprises the steps of mixing the raw materials in a dry mode for 3-5 minutes, adding aluminum dihydrogen phosphate with the mass percentage of 4% -6%, mixing the raw materials in a mixing roll for 15 minutes, performing punch forming according to the weight of 2-3 hammers/kilogram after mixing, drying the mixture in a dryer at the temperature of 80-120 ℃ for 24-48 hours until the moisture content is less than 0.5%, sintering the mixture until the temperature is kept at 1450 ℃ for 12 hours.

Example 2

A low-heat-conductivity refractory material for high-temperature pipeline systems is selected from the following components in percentage by mass: 20% of microporous sintered corundum, 12% of mullite, 28% of andalusite, 34% of andalusite powder and 6% of aluminum hydroxide. Wherein the micropore sintered corundum comprises 15% of micropore sintered corundum with granularity distribution of 1-3 mm and 5% of micropore sintered corundum with granularity of less than or equal to 1mm, and the micropore sintered corundum comprises Al with mass content of not less than 99%₂O₃And Fe with the mass content not higher than 0.1%₂O₃The apparent porosity of the micropore sintered corundum is less than or equal to 5 percent, and the closed porosity is more than or equal to 6 percent; the mullite has the particle size distribution of 1-3 mm and contains Al with the mass content not less than 72%₂O₃Quality of harmonyFe in an amount of not more than 0.5%₂O₃And the mass content of the mullite is more than or equal to 92 percent; the andalusite comprises 18% of andalusite with the particle size distribution of 1-3 mm and 10% of andalusite with the particle size of less than or equal to 1mm, the granularity of andalusite powder is less than or equal to 0.08mm, and the andalusite powder respectively comprise Al with the mass content of not less than 57%₂O₃And Fe with a mass content of not more than 1%₂O₃(ii) a The particle size of the aluminum hydroxide is less than or equal to 5 microns.

Preferably, the preparation method of the low-heat-conductivity refractory material for the high-temperature pipeline system comprises the steps of mixing the raw materials in a dry mode for 3-5 minutes, adding aluminum dihydrogen phosphate with the mass percentage of 4% -6%, mixing the raw materials in a mixing roll for 15 minutes, performing punch forming according to the weight of 2-3 hammers/kilogram after mixing, drying the mixture in a dryer at the temperature of 80-120 ℃ for 24-48 hours until the moisture content is less than 0.5%, sintering the mixture until the temperature is kept at 1450 ℃ for 12 hours.

Example 3

A low-heat-conductivity refractory material for high-temperature pipeline systems is selected from the following components in percentage by mass: 30% of microporous sintered corundum, 10% of mullite, 20% of andalusite, 30% of andalusite powder and 10% of aluminum hydroxide. Wherein the micropore sintered corundum comprises 20% of micropore sintered corundum with granularity distribution of 1-3 mm and 10% of micropore sintered corundum with granularity of less than or equal to 1mm, and the micropore sintered corundum comprises Al with mass content of not less than 99%₂O₃And Fe with the mass content not higher than 0.1%₂O₃The apparent porosity of the micropore sintered corundum is less than or equal to 5 percent, and the closed porosity is more than or equal to 6 percent; the mullite has the particle size distribution of 1-3 mm and contains Al with the mass content not less than 72%₂O₃And Fe with the mass content not higher than 0.5%₂O₃And the mass content of the mullite is more than or equal to 92 percent; the andalusite comprises 15% of andalusite with the particle size distribution of 1-3 mm and 5% of andalusite with the particle size of less than or equal to 1mm, the granularity of andalusite powder is less than or equal to 0.08mm, and the andalusite powder respectively comprise Al with the mass content of not less than 57%₂O₃And Fe with a mass content of not more than 1%₂O₃(ii) a The particle size of the aluminum hydroxide is less than or equal to 5 microns.

Preferably, the preparation method of the low-heat-conductivity refractory material for the high-temperature pipeline system comprises the steps of mixing the raw materials in a dry mode for 3-5 minutes, adding aluminum dihydrogen phosphate with the mass percentage of 4% -6%, mixing the raw materials in a mixing roll for 15 minutes, performing punch forming according to the weight of 2-3 hammers/kilogram after mixing, drying the mixture in a dryer at the temperature of 80-120 ℃ for 24-48 hours until the moisture content is less than 0.5%, sintering the mixture until the temperature is kept at 1450 ℃ for 12 hours.

Tests show that the refractory products obtained in the above examples 1 to 3 all meet the requirements of apparent porosity of less than or equal to 20%, refractoriness under load of more than or equal to 1650 ℃, thermal shock, 1100 ℃ water cooling of more than or equal to 20 times, and thermal conductivity of more than or equal to 2.1w/mk, and completely meet the use requirements of high-temperature pipelines. The results of physical and chemical measurements of the refractory products obtained in examples 1 to 3 are shown in Table 1.

TABLE 1 Performance index of low thermal conductivity refractory for high temperature pipeline system

	Air ratio,% of	Refractoriness under load onset temperature, DEG C	Thermal conductivity, 1200 ℃, w/mk	Thermal shock, 1100 deg.C water cooling
					Example 1	18.9	1670	2.01	Not less than 20 times
Example 2	19.4	1660	2.03	Not less than 20 times
					Example 3	19.5	1660	1.97	Not less than 20 times

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.