CN115259871B

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Publication number: CN115259871B
Application number: CN202210936840.3A
Authority: CN
Inventors: 李振方; 李保勤; 李洪城; 苏朝炬; 苏利学
Original assignee: Qinghe Chenglin Refractory Co ltd; Shandong Chenglin Refractory Co ltd
Current assignee: Qinghe Chenglin Refractory Co ltd; Shandong Chenglin Refractory Co ltd
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2023-05-12
Anticipated expiration: 2042-08-05
Also published as: CN115259871A

Abstract

The invention provides a magnesium insulation board, a preparation method and application thereof, wherein pore diameters of pores in the magnesium insulation board are distributed gradually, and the pore sizes and the porosities of the pores are gradually increased from the bottom to the top of the magnesium insulation board; the raw materials of the magnesium insulation board comprise magnesite aggregate, magnesite powder, soft clay, silica micropowder, metal aluminum powder and sugar solution; the invention combines the thermal foaming technology, and utilizes the weight of the blank body to form a structure with gradually changed air holes; the magnesite is used as a main raw material, the sugar solution is used as a binding agent, and a specific drying mode is utilized, so that the production cost is reduced, and the binding strength is improved; the obtained magnesium heat-insulating plate has excellent heat-insulating performance and erosion resistance, high breaking strength, low heat conductivity coefficient, low cost and simple preparation process, and can greatly prolong the service life of the heat-insulating plate by being used as a refractory material, thereby having good application prospect.

Description

Magnesia heat insulation plate and preparation method and application thereof

Technical Field

The invention belongs to the technical field of refractory materials, and particularly relates to a magnesium insulation board and a preparation method and application thereof.

Background

The magnesium heat-insulating plate is a common refractory material at the parts of a tundish and the like, the refractory material at the parts can be directly contacted with molten steel, slag, covering agent and the like in the steelmaking continuous casting production process, and the magnesium heat-insulating plate needs to bear the erosion, scouring and penetration of the molten steel and slag, and has more severe service conditions. The magnesium insulation board has the characteristics of small volume density, high porosity, low heat conductivity, good heat preservation effect and the like, and has the capability of purifying molten steel.

CN101544506B discloses a raw material formulation of a tundish insulation board, wherein the raw materials (mass percent) comprise 30-50% of olive sand, 15-25% of magnesia, 25-40% of waste magnesia bricks, 4-8% of magnesium chloride and 0.2-0.5% of hardener; the method comprises the following steps of adopting the raw material formula of the tundish heat-insulating plate to manufacture the tundish heat-insulating plate: 1) Preparing raw materials, mixing and stirring; 2) Adding water accounting for 5.5-7.5% of the total mass of the raw materials into the stirred raw materials, mixing and stirring for 3-5min, and then placing the raw materials into a mould for vibration molding; 3) Demolding after molding for 1-2 hours; 4) And the demoulded tundish insulating board enters a drying room for baking, wherein the baking temperature is 120-150 ℃ and the baking time is 6-8 hours. The method adopts magnesium chloride as a binding agent, has no smoke and pungent smell in baking and use, is suitable for smelting clean steel and ultra-low carbon steel, and simplifies the production process, reduces operators and reduces the production cost and equipment investment due to the casting molding of the die.

CN110563474B discloses an aluminum-magnesium refractory insulation board, which comprises the following components in mass: 100 parts of refractory fiber, 1-15 parts of calcium aluminate, 1-20 parts of silanol, 1-15 parts of aluminum sulfate, 1-3 parts of oxalic acid, 0.5-2 parts of polyacrylamide and 200-500 parts of water; has the effects of fire resistance and heat insulation, light weight and good construction performance.

However, in the prior art, the magnesia heat insulation plate has high porosity and low heat conductivity coefficient, but the high porosity also reduces the slag erosion and penetration resistance of the refractory material. In addition, the current magnesia heat-insulating plate takes electric melting or sintering magnesia as a main raw material, and a large amount of energy is consumed in the preparation process of the raw materials, so that the preparation cost of the magnesia heat-insulating plate is increased.

In order to solve the problems, there is a need to develop a magnesium insulation board with excellent erosion resistance and penetration resistance, excellent heat insulation performance and low cost, which meets the development requirement of continuous casting production.

Disclosure of Invention

The invention aims to provide a magnesia heat-insulating plate and a preparation method and application thereof, wherein magnesite is used as a main raw material, so that the preparation cost of a refractory material is reduced; the sugar solution is used as a binding agent, so that the binding strength between blanks is improved; the prepared magnesium insulation board has excellent heat insulation performance and erosion resistance, high flexural strength, low heat conductivity coefficient, low cost and simple preparation process, can be used as a refractory material to greatly prolong the service life, and has good application prospect.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

in a first aspect, the invention provides a magnesium insulation board, wherein pore diameters of pores in the magnesium insulation board are distributed gradually, and pore sizes and porosities of the pores are gradually increased from the bottom to the top of the magnesium insulation board;

the raw materials of the magnesium insulation board comprise magnesite aggregate, magnesite powder, soft clay, silica micropowder, metal aluminum powder and sugar solution.

In the magnesium insulation board, the side with smaller air holes is relatively compact, can be directly contacted with molten steel, ensures erosion resistance, is relatively loose, and can further improve the heat insulation performance of the magnesium insulation board.

According to the invention, magnesite is used as a main raw material, magnesium oxide formed by the magnesite in the baking process is in a porous structure, pore diameters of air holes generated by decomposition are small, and the magnesia heat insulation plate is endowed with more excellent heat insulation performance; in addition, the pores generated by the decomposition of magnesite are mostly of closed pore structures, so that slag cannot permeate into the pores, and the integral erosion resistance of the magnesia heat insulation plate is ensured; finally, the magnesite contains a small amount of CaO and SiO₂ 、Fe₂ O₃ 、Al₂ O₃ The impurities can form a low-melting phase in the service process, so that the sintering of the magnesium insulation board is promoted, and the structural integrity of the material is improved.

As a preferable technical scheme of the invention, the raw materials of the magnesium insulation board comprise 60-70 parts by mass of magnesite aggregate, 8-16 parts by mass of magnesite powder, 8-12 parts by mass of soft clay, 6-12 parts by mass of silica micropowder, 2-6 parts by mass of metal aluminum powder and 4-12 parts by mass of sugar solution.

The magnesite aggregate is 60-70 parts, such as 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts or 70 parts; the magnesite powder is 8-16 parts, for example, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or 16 parts; the soft clay is 8-12 parts, for example, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts; the silicon micropowder is 6-12 parts, for example, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts; 2-6 parts of metal aluminum powder, such as 2 parts, 3 parts, 4 parts, 5 parts or 6 parts; the sugar solution may be 4 to 12 parts, for example, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts, but is not limited to the listed values, and other non-listed values within the above-mentioned range are equally applicable.

As a preferable technical scheme of the invention, in the magnesite aggregate, the content of the magnesite aggregate with the grain size of 3-5mm is 35-50wt%, the content of the magnesite aggregate with the grain size of 1-3mm is 25-40wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 10-25wt%.

The magnesite aggregate has a particle size of 3-5mm, the magnesite aggregate content is 35-50wt%, the particle size is 3-5mm, for example, 3mm, 3.2mm, 3.6mm, 4mm, 4.3mm, 4.7mm or 5mm, the magnesite aggregate content is 35-50wt%, for example, 35wt%, 40wt%, 42wt%, 46wt%, 50wt%, 53wt% or 55wt%; the magnesite aggregate with the grain size of 1-3mm is 25-40wt%, the grain size of 1-3mm, such as 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.7mm or 3mm, and the content of 25-40wt%, such as 25wt%, 27wt%, 30wt%, 32wt%, 35wt%, 38wt% or 40wt%; the magnesite aggregate having a particle size of 0.1-1mm is contained in an amount of 10-25wt%, the particle size is 0.1-1mm, for example, 0.1mm, 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm or 1mm, and the magnesite aggregate having a particle size of 10-25wt%, for example, 10wt%, 12wt%, 14wt%, 18wt%, 20wt%, 22wt% or 25wt%, but the present invention is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are applicable.

It is worth noting that, in the invention, the magnesite aggregate with the grain size of 3-5mm does not comprise the magnesite aggregate with the grain size of 3 mm; the magnesite aggregate with the grain size of 1-3mm comprises magnesite aggregate with the grain size of 3mm and does not comprise magnesite aggregate with the grain size of 1 mm; the magnesite aggregate with the grain size of 0.1-1mm comprises magnesite aggregate with the grain size of 1 mm.

In a preferred embodiment of the present invention, the particle size of the magnesite powder is not more than 0.088mm, and may be, for example, 0.001mm, 0.010mm, 0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm or 0.088mm, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned numerical ranges are equally applicable.

Preferably, the MgO content in the magnesite powder is not less than 50wt%, for example, 50wt%, 53wt%, 56wt%, 60wt%, 65wt%, 70wt%, 72wt%, 77wt%, 80wt%, 83wt%, 86wt%, 90wt%, 92wt% or 96wt%, but is not limited to the recited values, and other non-recited values within the above-mentioned range are equally applicable.

The particle size of the soft clay is preferably not more than 0.088mm, and may be, for example, 0.001mm, 0.010mm, 0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm or 0.088mm, but not limited to the above-mentioned values, and other values not mentioned in the above-mentioned numerical ranges are equally applicable.

Preferably, in the soft clay, al₂ O₃ The content of (C) may be 30wt%, 33wt%, 37wt%, 40wt%, 42wt%, 46wt%, 50wt%, 54wt%, 58wt%, 60wt%, 64wt%, 68wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt% or 95wt%, for example, but is not limited to the recited values, and other non-recited values within the above-recited ranges may be equally applied.

In a preferred embodiment of the present invention, the particle size of the fine silica powder is not more than 1. Mu.m, for example, 0.1. Mu.m, 0.2. Mu.m, 0.3. Mu.m, 0.4. Mu.m, 0.5. Mu.m, 0.6. Mu.m, 0.7. Mu.m, 0.8. Mu.m, 0.9. Mu.m, or 1. Mu.m, but the fine silica powder is not limited to the above-mentioned values, and other values not listed in the above-mentioned numerical ranges are similarly applicable.

PreferablyIn the silicon micropowder, siO₂ The content of (C) may be 95wt%, 95.5wt%, 96wt%, 96.5wt%, 97wt%, 97.5wt%, 98wt%, 98.5wt%, 99wt% or 99.5wt%, for example, but is not limited to the values recited, and other values not recited in the above ranges are equally applicable.

The particle diameter of the metal aluminum powder is preferably not more than 5. Mu.m, and may be, for example, 0.5. Mu.m, 1. Mu.m, 1.5. Mu.m, 2. Mu.m, 2.5. Mu.m, 3. Mu.m, 3.5. Mu.m, 4.5. Mu.m, or 5. Mu.m, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned value ranges are equally applicable.

Preferably, the aluminum content of the metal aluminum powder is equal to or greater than 99wt%, and may be, for example, 99wt%, 99.1wt%, 99.2wt%, 99.3wt%, 99.4wt%, 99.5wt%, 99.6wt%, 99.7wt%, 99.8wt%, or 99.9wt%, but is not limited to the recited values, and other non-recited values within the above-recited values are equally applicable.

In a preferred embodiment of the present invention, the sugar solution has a solute content of 20 to 60wt%, for example, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%, but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned ranges are equally applicable.

Preferably, the solute of the sugar solution comprises any one or a combination of at least two of sucrose, glucose, fructose or maltose, typical but non-limiting examples of which include a combination of sucrose and glucose, a combination of sucrose and fructose, a combination of sucrose and maltose, a combination of glucose and fructose, a combination of glucose and maltose, and a combination of fructose and maltose.

Preferably, the solvent of the sugar solution comprises water.

In a second aspect, the present invention provides a method for preparing the magnesium insulation board according to the first aspect, the method comprising the following steps:

(1) Firstly mixing magnesite aggregate and a sugar solution to obtain a first mixed material; carrying out second mixing on magnesite powder, soft clay, silicon micropowder and metal aluminum powder with the first mixed material to obtain a second mixed material;

(2) The second mixed material in the step (1) is subjected to material trapping and compression molding in sequence to obtain a biscuit;

(3) And (3) sequentially carrying out first drying and second drying on the biscuit in the step (2) to obtain the magnesium insulation board.

The invention combines the thermal foaming technology, and utilizes the weight of the blank body to form a gradual change structure with one side of big air holes and one side of small air holes; according to the invention, sugar solution is used as a binding agent, and sugar is dehydrated and condensed to generate caramel and carbon dioxide during first drying, so that the blank body starts to expand to different degrees to form a gradual porous structure; and in the second drying process, the residual caramel is further reacted with air and oxidized into carbon dioxide and water, organic components are completely oxidized, and meanwhile, the metal aluminum powder starts to oxidize and melt, so that the bonding strength between blanks is improved.

In a preferred embodiment of the present invention, the time of the first mixing in the step (1) is 5-15min, for example, 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, and 15min, but the present invention is not limited to the above-mentioned values, and other values not listed in the above-mentioned value ranges are equally applicable.

Preferably, the second mixing time in step (1) is 15-20min, for example, 15min, 15.5min, 16min, 16.5min, 17min, 17.5min, 18min, 18.5min, 19min, 19.5min or 20min, but not limited to the recited values, and other non-recited values within the above range are equally applicable.

The temperature of the trapped material in the step (2) is preferably 10 to 30 ℃, and may be, for example, 10 ℃, 12 ℃, 14 ℃, 16 ℃, 18 ℃, 20 ℃, 22 ℃, 24 ℃, 26 ℃, 28 ℃ or 30 ℃, but is not limited to the values listed, and other values not listed in the above-mentioned value ranges are equally applicable.

Preferably, the time of the trapping material in the step (2) is 12-24h, for example, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or 24h, but not limited to the listed values, and other non-listed values in the above range are equally applicable.

Preferably, the pressure of the press molding in the step (2) is 20 to 50MPa, for example, 20MPa, 23MPa, 25MPa, 27MPa, 30MPa, 33MPa, 35MPa, 38MPa, 40MPa, 42MPa, 45MPa, 47MPa or 50MPa, but the pressure is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value ranges are equally applicable.

In a preferred embodiment of the present invention, the temperature of the first drying in the step (3) is 190 to 240. DegreeC, for example, 190. DegreeC, 195. DegreeC, 200. DegreeC, 205. DegreeC, 210. DegreeC, 215. DegreeC, 220. DegreeC, 225. DegreeC, 230. DegreeC, 235. DegreeC, 240. DegreeC, but not limited to the values listed, and other values not listed in the above-mentioned value range are equally applicable.

Preferably, the time of the first drying in the step (3) is 3-6h, for example, 3h, 3.2h, 3.7h, 4h, 4.3h, 4.6h, 5h, 5.4h, 5.8h or 6h, but not limited to the recited values, and other non-recited values in the above range are equally applicable.

Preferably, the temperature of the second drying in the step (3) is 400-700 ℃, for example, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃ or 700 ℃, but the second drying is not limited to the listed values, and other non-listed values in the above-mentioned range are equally applicable.

Preferably, the second drying time in step (3) is 3-8h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8h, but not limited to the recited values, and other non-recited values within the above range are equally applicable.

The preparation method of the magnesium insulation board is worth to be explained, and comprises the following steps:

(1) Firstly mixing 60-70 parts of magnesite aggregate and 4-12 parts of sugar solution for 5-15min to obtain a first mixed material; mixing 8-16 parts of magnesite powder with the particle size less than or equal to 0.088mm, 8-12 parts of soft clay with the particle size less than or equal to 0.088mm, 6-12 parts of silicon micro powder with the particle size less than or equal to 1 mu m, 2-6 parts of metal aluminum powder with the particle size less than or equal to 5 mu m with the first mixed material for 15-20min to obtain a second mixed material;

wherein, the content of the magnesite aggregate with the grain diameter of 3-5mm in the magnesite aggregate is 35-50wt%,the content of the magnesite aggregate with the grain size of 1-3mm is 25-40wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 10-25wt%; the content of solute in the sugar solution is 20-60wt%; the solute of the sugar solution comprises any one or a combination of at least two of sucrose, glucose, fructose or maltose, and the solvent comprises water; the MgO content in the magnesite powder is more than or equal to 50wt%; al in soft clay₂ O₃ The content of (2) is more than or equal to 30wt%; siO in the silicon micropowder₂ The content of (2) is more than or equal to 95wt%; the aluminum content of the metal aluminum powder is more than or equal to 99wt%;

(2) The second mixed material is trapped for 12-24 hours at the temperature of 10-30 ℃; pressing and forming at 20-50MPa to obtain a biscuit;

(3) The biscuit in the step (2) is first dried for 3 to 6 hours at the temperature of 190 to 240 ℃; and (3) drying for 3-8 hours at 400-700 ℃ to obtain the magnesium insulation board.

In a third aspect, the present invention provides the use of a magnesium insulation panel according to the first aspect as a refractory material.

The numerical ranges recited herein include not only the above-listed point values, but also any point values between the above-listed numerical ranges that are not listed, and are limited in space and for the sake of brevity, the present invention is not intended to be exhaustive of the specific point values that the stated ranges include.

Compared with the prior art, the invention has the following beneficial effects:

(1) According to the magnesium insulation board and the preparation method thereof, the weight of a blank body is utilized to form a structure with gradually changed air holes by combining a thermal foaming technology; the magnesite is used as a main raw material, the sugar solution is used as a binding agent, and a specific drying mode is utilized, so that the production cost is reduced, and the binding strength between blanks is improved;

(2) The magnesia heat-insulating plate has excellent heat-insulating performance and erosion resistance, high breaking strength, low heat conductivity coefficient, low cost and simple preparation process, can greatly prolong the service life of the magnesia heat-insulating plate by being used as a refractory material, and has good application prospect.

Drawings

FIG. 1 is a cross-sectional view of a magnesium insulation panel according to example 1 of the present invention;

FIG. 2 is a graph showing the pore size distribution of the bottom of the magnesium insulation panel according to example 1 of the present invention;

fig. 3 is a graph showing the pore size distribution of the top of the magnesium insulation panel obtained in example 1 of the present invention.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

It is worth noting that in the specific embodiment of the invention, the grain size of the magnesite powder is less than or equal to 0.088mm; the particle size of the soft clay is less than or equal to 0.088mm; the grain diameter of the silicon micropowder is less than or equal to 1 mu m; the grain diameter of the metal aluminum powder is less than or equal to 5 mu m.

Example 1

The embodiment provides a magnesium insulation board and a preparation method thereof, wherein the preparation method of the magnesium insulation board comprises the following steps:

(1) Carrying out first mixing on 60 parts of magnesite aggregate and 12 parts of sugar solution for 15min to obtain a first mixed material; mixing 10 parts of magnesite powder, 10 parts of soft clay, 8 parts of silicon micropowder and 2 parts of metal aluminum powder with the first mixed material for 20min to obtain a second mixed material;

wherein, in the magnesite aggregate, the content of the magnesite aggregate with the grain size of 3-5mm is 50wt%, the content of the magnesite aggregate with the grain size of 1-3mm is 40wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 10wt%; the content of solute in the sugar solution was 50wt%; the solute of the sugar solution is sucrose, and the solvent is water; the MgO content in the magnesite powder is 70wt%; al in soft clay₂ O₃ The content of (2) is 35wt%; siO in the silicon micropowder₂ The content of (2) is 98wt%; the aluminum content of the metal aluminum powder is 99wt%;

(2) The second mixed material is trapped for 24 hours at 20 ℃ in the step (1); pressing and forming at 50MPa to obtain a biscuit;

(3) The biscuit in the step (2) is first dried for 6 hours at 220 ℃; and (5) drying for 5 hours at 550 ℃ to obtain the magnesium insulation board.

The cross-sectional morphology of the magnesium insulation board obtained in the embodiment is shown in fig. 1, and as can be seen from fig. 1, the pore diameter of the top air hole is obviously larger than that of the bottom air hole, and the pore diameters of the magnesium insulation board are distributed gradually from top to bottom; the pore size distribution of the bottom of the obtained magnesium insulation board is shown in figure 2, and as can be obtained from figure 2, the average pore size of the bottom of the magnesium insulation board is 2.4 mu m; the pore size distribution of the top of the obtained magnesium insulation panel is shown in fig. 3, and as can be seen from fig. 3, the average pore size of the top of the magnesium insulation panel is 19.6 μm.

Example 2

(1) Carrying out first mixing on 70 parts of magnesite aggregate and 10 parts of sugar solution for 10min to obtain a first mixed material; carrying out second mixing on 16 parts of magnesite powder, 12 parts of soft clay, 12 parts of silica micropowder and 3 parts of metal aluminum powder with the first mixed material for 15min to obtain a second mixed material;

wherein, in the magnesite aggregate, the content of the magnesite aggregate with the grain size of 3-5mm is 50wt%, the content of the magnesite aggregate with the grain size of 1-3mm is 25wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 25wt%; the content of solute in the sugar solution was 60wt%; the solute of the sugar solution is glucose, and the solvent is water; the MgO content in the magnesite powder is 50wt%; al in soft clay₂ O₃ The content of (2) is 30wt%; siO in the silicon micropowder₂ The content of (2) is 95wt%; the aluminum content of the metal aluminum powder is 99wt%;

(2) The second mixed material is trapped for 12 hours at the temperature of 30 ℃; pressing and forming at 20MPa to obtain a biscuit;

(3) The biscuit in the step (2) is first dried for 3 hours at 240 ℃; and (5) performing secondary drying at 400 ℃ for 8 hours to obtain the magnesium insulation board.

Example 3

(1) Carrying out first mixing on 65 parts of magnesite aggregate and 4 parts of sugar solution for 5min to obtain a first mixed material; carrying out second mixing on 8 parts of magnesite powder, 8 parts of soft clay, 6 parts of silicon micropowder and 6 parts of metal aluminum powder with the first mixed material for 20min to obtain a second mixed material;

wherein, in the magnesite aggregate, the content of the magnesite aggregate with the grain size of 3-5mm is 35wt%, the content of the magnesite aggregate with the grain size of 1-3mm is 40wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 25wt%; the content of solute in the sugar solution was 20wt%; the solute of the sugar solution is sucrose and glucose, and the solvent is water; the MgO content in the magnesite powder is 80wt%; al in soft clay₂ O₃ The content of (2) is 50wt%; siO in the silicon micropowder₂ The content of (2) is 95wt%; the aluminum content of the metal aluminum powder is 99wt%;

(2) The second mixed material is trapped for 20 hours at the temperature of 10 ℃; compacting and forming at 40MPa to obtain a biscuit;

(3) The biscuit in the step (2) is first dried for 6 hours at 190 ℃; and (3) drying for 3 hours at 700 ℃ to obtain the magnesium insulation board.

Comparative example 1

This comparative example provides a magnesium insulation board and a method for manufacturing the same, which is different from the method for manufacturing example 1 only in that: the equal mass of the sugar solution in the step (1) is replaced by phenolic resin.

Comparative example 2

This comparative example provides a magnesium insulation board and a method for manufacturing the same, which is different from the method for manufacturing example 1 only in that: in the step (1), the equal mass of the magnesite aggregate is replaced by forsterite aggregate, and the equal mass of the magnesite powder is replaced by forsterite powder.

The performance of the magnesium insulation panels obtained in the above examples and comparative examples was tested as follows:

pore diameters of pores at the top and the bottom of the magnesium insulation board: measured using an Autopore 9501 type IV mercury porosimeter from Mickey corporation;

volume density of top and bottom of magnesium insulation panel: measuring by adopting an Archimedes drainage method;

thermal conductivity of the top and the bottom of the magnesium insulation board: measuring by adopting a flat plate heat conduction method;

flexural strength of magnesium insulation board: the three-point bending method is adopted for measurement;

the results of the above tests are shown in Table 1.

TABLE 1

From table 1, the following points can be found:

(1) It can be seen from examples 1 to 3 that the top and bottom of the magnesium insulation panel obtained by the present invention have different pore sizes, bulk densities and thermal conductivities; the top air hole has large size, small volume density, low heat conductivity and excellent heat insulation performance; the bottom air hole has small size, large volume density, high heat conductivity and excellent erosion resistance; not only meets the corrosion resistance requirement of the magnesium heat-insulating plate, but also realizes the heat-insulating performance;

(2) Comparing example 1 with comparative example 1, the comparative example 1 replaces the equal mass of the sugar solution with phenolic resin, so that the difference of the pore structures at the top and the bottom of the magnesium insulation board is not large, and the requirements of corrosion resistance, heat insulation and heat preservation of the magnesium insulation board cannot be met at the same time;

(3) Comparing example 1 with comparative example 2, the top heat insulation performance and bottom erosion resistance of the composite material are reduced because the comparative example 2 replaces the equal mass of magnesite aggregate with forsterite aggregate and the equal mass of magnesite powder with forsterite powder.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. The magnesium insulation board is characterized in that pore diameters of pores in the magnesium insulation board are distributed gradually, and the pore sizes and the porosities of the pores are gradually increased from the bottom to the top of the magnesium insulation board;

the raw materials of the magnesium insulation board comprise 60-70 parts by mass of magnesite aggregate, 8-16 parts by mass of magnesite powder, 8-12 parts by mass of soft clay, 6-12 parts by mass of silica micropowder, 2-6 parts by mass of metal aluminum powder and 4-12 parts by mass of sugar solution;

in the magnesite aggregate, the content of the magnesite aggregate with the grain size of 3-5mm is 35-50wt%, the content of the magnesite aggregate with the grain size of 1-3mm is 25-40wt%, and the content of the magnesite aggregate with the grain size of 0.1-1mm is 10-25wt%;

the magnesium insulation board is prepared by adopting the following preparation method, and the preparation method comprises the following steps:

(3) Sequentially carrying out first drying and second drying on the biscuit in the step (2) to obtain a magnesium insulation board;

the temperature of the first drying in the step (3) is 190-240 ℃;

the temperature of the second drying in the step (3) is 400-700 ℃.

2. A magnesium insulation panel according to claim 1 wherein the particle size of the magnesite powder is less than or equal to 0.088mm.

3. A magnesium insulation panel according to claim 1 wherein the MgO content of the magnesite powder is greater than or equal to 50wt%.

4. The magnesium insulation panel according to claim 1, wherein the particle size of the soft clay is 0.088mm or less.

5. The magnesium insulation panel according to claim 1, wherein Al in the soft clay₂ O₃ The content of (2) is more than or equal to 30wt%.

6. A magnesium insulation panel according to claim 1 wherein the particle size of the fine silica powder is 1 μm or less.

7. A magnesium insulation panel according to claim 1, wherein said fine silica powder comprises SiO₂ The content of (2) is more than or equal to 95 weight percent.

8. The magnesium insulation panel according to claim 1, wherein the particle size of the metal aluminum powder is 5 μm or less.

9. The magnesium insulation panel according to claim 1, wherein the aluminum content of the metal aluminum powder is not less than 99wt%.

10. A magnesium insulation panel according to claim 1 wherein the solute content of the sugar solution is 20-60wt%.

11. The magnesium insulation panel of claim 1 wherein the solute of the sugar solution comprises any one or a combination of at least two of sucrose, glucose, fructose or maltose.

12. A magnesium insulation panel according to claim 1 wherein the solvent of the sugar solution comprises water.

13. A method of producing a magnesium insulation panel according to any one of claims 1 to 12, wherein the method comprises the steps of:

the temperature of the first drying in the step (3) is 190-240 ℃;

the temperature of the second drying in the step (3) is 400-700 ℃.

14. The method of claim 13, wherein the first mixing in step (1) is for a period of time ranging from 5 to 15 minutes.

15. The method of claim 13, wherein the second mixing in step (1) is for a period of 15-20 minutes.

16. The method of claim 13, wherein the temperature of the trapped material in step (2) is 10-30 ℃.

17. The method of claim 13, wherein the time for the trapping in step (2) is 12-24 hours.

18. The method according to claim 13, wherein the pressure of the press molding in the step (2) is 20 to 50MPa.

19. The method of claim 13, wherein the first drying in step (3) is for a period of 3 to 6 hours.

20. The method of claim 13, wherein the second drying in step (3) is performed for a period of 3 to 8 hours.

21. Use of a magnesium insulation panel according to any of claims 1-12, wherein the magnesium insulation panel is used as a refractory material.