High-temperature-resistant high-load softening point refractory brick and preparation method thereof

Abstract

The invention provides a high-temperature-resistant high-load softening point refractory brick which sequentially comprises a heat preservation layer and a fireproof layer from outside to inside, a supporting net frame is arranged between the heat preservation layer and the fireproof layer, and the fireproof layer comprises the following raw materials in percentage by mass: 48%-80% of high bauxite clinker large particles, 3%-5% of calcium aluminate cement, 5%-10% of titanium dioxide, 5%-10% of silicon dioxide, 5%-10% of silicon dioxide, 5%-10% of silicon dioxide and 5%-10% of silicon dioxide. The invention relates to a refractory brick with high temperature resistance and high load softening point, which comprises the following components in percentage by weight: 6-10% of alumina, 6-10% of spinel, 5-14% of kaolin micro powder and 1-3% of silicon powder, and a preparation method of the refractory brick with high temperature resistance and high load softening point comprises the steps of raw material processing, mixing, molding, drying, sintering and inspection. By improving the purity of aluminum oxide in high-alumina bauxite and adding calcium aluminate cement, titanium dioxide and spinel, the high-alumina bauxite and aluminum oxide form a stable phase state under a high-temperature condition, and the problems that the softening point of the refractory brick is reduced due to the fact that the binding force among different components of the refractory brick is not tight, and the refractory brick is difficult to crack are solved. Meanwhile, the supporting net rack is arranged between the fireproof layer and the heat preservation layer, so that the internal structures of the heat preservation layer and the fireproof layer are better fixed.

Description

Technical Field

[0001] The invention relates to the field of refractory materials, and in particular to a high-temperature resistant and high-load softening point refractory brick and a preparation method thereof. Background Art

[0002] Refractory bricks are refractory materials made by firing refractory clay or other refractory raw materials. It can withstand high temperatures without being easily softened, deformed or damaged, and is a key material for the lining of high-temperature equipment such as industrial kilns. High temperature resistance and high load softening point are important performance parameters of refractory bricks. A low softening point means that when the temperature reaches or approaches the softening point of the refractory brick, the brick body will deform. This deformation may be uneven, which will cause the structural integrity of the kiln to be destroyed. The originally regularly arranged refractory bricks may bend, collapse, etc., which will affect the internal spatial structure of the kiln. For some kiln processes that require high dimensional accuracy (such as glass kilns, where the flow and forming of the glass liquid are closely related to the internal spatial structure of the kiln), it will cause serious product quality problems.

[0003] At present, the softening point of ordinary refractory bricks is 1400℃-1500℃. In medium-sized glass kilns, ceramic kilns and other kilns, the refractoriness of refractory bricks is usually required to be between 1770℃-2000℃. Therefore, ordinary refractory bricks cannot meet the usage standards. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a high temperature resistant and high load softening point refractory brick and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: high temperature resistant and high load softening point refractory bricks, the high temperature resistant and high load softening point refractory bricks include a thermal insulation layer and a fireproof layer from the outside to the inside, a supporting grid is provided between the thermal insulation layer and the fireproof layer, and the fireproof layer includes the following raw materials in mass percentage: 48%-80% of large particles of high alumina clinker, 3%-5% of calcium aluminate cement, 5%-10% of titanium dioxide, 6%-10% of spinel, 5%-14% of kaolin powder, and 1%-3% of silicon powder.

[0006] Furthermore, the refractory bricks contain 70% of the large particles of high-alumina clinker, 4% of calcium aluminate cement, 6% of titanium dioxide, 8% of spinel, 10% of kaolin powder, and 2% of silica fume.

[0007] Furthermore, the particle size of the large particles of high-alumina clinker is 1-2 mm.

[0008] Furthermore, the particle size of the kaolin powder is less than 0.043 mm.

[0009] Furthermore, the thickness of the thermal insulation layer is half the thickness of the fireproof layer.

[0010] Furthermore, the material of the supporting grid is a high temperature resistant rigid material.

[0011] A method for preparing high temperature resistant and high load softening point refractory bricks comprises the following steps: S1: Screening large particles of high-alumina clinker and kaolin powder to appropriate sizes; S2: Mix and knead the raw materials according to the proportion; S3: filling the mixed raw materials into a mold and shaping them to obtain fireproof layer bricks; S4: adding a layer of supporting grid on the obtained fireproof layer brick; S5: pre-sintering the fireproof layer bricks and the supporting grid at 80°C-95°C to obtain unfired bricks, drying for 24-36 hours, and finally calcining at 1300-1500°C for 5-12 hours to obtain bricks; S6: pouring a thermal insulation layer on the surface of the brick, placing it in a mold to shape it, and obtaining a refractory brick; S7: calcining the refractory brick blanks at 1500-1700° C. to obtain high temperature resistant and high load softening point refractory bricks; S8: Inspection and analysis of high temperature resistant and high load softening point refractory bricks.

[0012] Furthermore, in step S6, the lower end of the support grid is fixedly connected to the fireproof layer bricks, and the upper end of the support grid is fixedly connected to the thermal insulation layer.

[0013] Furthermore, in step S5, the heating rate and cooling rate during the calcination process are controlled at 50-80° C. per hour.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: based on the prior art, the present invention improves the raw materials, binders, molding processes and additives of refractory bricks, thereby increasing the content of alumina in the raw materials, and the binder adopts calcium aluminate cement. At high temperatures, calcium aluminate can react with the raw materials to further improve the high temperature strength and stability of the brick body; the molding process and additives are optimized to further improve the softening point of the brick body; at the same time, the provision of the thermal insulation layer and the fireproof layer of the present invention enables the refractory brick to have better thermal insulation and fire resistance, which can meet the use of various furnaces and high-temperature buildings in various environments; the supporting grid contained in the refractory brick can support the overall structure of the refractory brick, prevent cracks in the thermal insulation layer, and extend the service life of the refractory brick. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A high temperature resistant and high load softening point refractory brick and a preparation method thereof according to Example 1 of the present invention; Figure 2 This is the experimental data table of Example 1; Figure 3 This is the experimental data table of Example 2; Figure 4 This is the experimental data table of Example 3; Explanation of numbers: 1-insulation layer; 2-fireproof layer; 3-support grid. DETAILED DESCRIPTION

[0016] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments. Example

[0017] The invention provides a high-temperature resistant and high-load softening point refractory brick, which comprises 70% of high-alumina clinker large particles, 4% of calcium aluminate cement, 6% of titanium dioxide, 8% of spinel, 10% of kaolin powder and 2% of silica powder.

[0018] like Figure 2 As shown in the table, the proportion of each chemical component of the raw materials is shown.

[0019] This embodiment also provides a method for preparing high temperature resistant and high load softening point refractory bricks, and the specific steps are as follows: First, the raw materials are screened separately, and 70% of large particles of high-alumina bauxite clinker, 4% of calcium aluminate cement, 6% of titanium dioxide, 8% of spinel, 10% of kaolin powder, and 2% of silica powder are mixed and stirred for 0.5-1h to obtain a mixture. After stirring, continue to add an appropriate amount of water to the mixture, stir and mix continuously to mix evenly, and age it for 24-36 hours to obtain a mixed slurry; use a brick-making mold to make bricks from the mixed slurry to obtain a brick blank, then add a layer of support grid 3 on the surface of the brick blank, insert the lower end of the support grid 3 into the brick blank 1-2CM, and then pre-sinter at 80-95℃ to obtain a brick to be fired, ensuring that the support grid 3 and the brick blank are initially fixed; finally, keep the temperature of the brick to be fired at a heating rate of 60℃ per hour until it reaches 1400℃, keep it warm and calcine it for 8 hours, and then let the brick to be fired cool at a cooling rate of 80℃ per hour. At this time, the various components in the brick to be fired have been combined together. Start; then pour a layer of insulation layer on the upper surface of the support grid 3, and shape it in the mold to ensure that the upper end of the support grid 3 enters the insulation layer 1 by 1-2CM to obtain a refractory brick blank; finally, keep the refractory brick blank at a heating rate of 70°C per hour until it reaches 1600°C, and keep it warm for 7 hours. Finally, the cooling conditions ensure uniform cooling at 120 degrees per hour to complete the second calcination, fully ensuring that the particles inside the refractory brick will be further sintered, so that the porosity is reduced, thereby increasing the volume density of the refractory brick, and at the same time making the internal crystal structure of the refractory brick more perfect, so that the heat transfer inside the brick body is more uniform and efficient. After testing, the softening point of this high temperature and high load softening point refractory brick is 1874.6°C. Compared with ordinary refractory bricks, the softening point is increased by 200-300 degrees Celsius. Example

[0020] like Figure 3 As shown, this embodiment provides a high temperature resistant and high load softening point refractory brick. The specific chemical composition ratio of the raw materials is roughly the same as that of the first embodiment. The difference is that spinel is not added in this embodiment, and the proportion of large particles of high alumina clinker is increased to 78%.

[0021] The method for preparing a high temperature resistant and high load softening point refractory brick described in this embodiment is the same as the method for preparing in embodiment 1. The high temperature resistant and high load softening point refractory brick produced in this embodiment has a softening point temperature of 1647.2°C after testing. Example

[0022] like Figure 4 As shown, this embodiment provides a high temperature resistant and high load softening point refractory brick. The specific raw material chemical composition is exactly the same as that of Example 1, and the chemical composition ratio is completely inconsistent. This embodiment includes 65% high alumina clinker large particles, 3% calcium aluminate cement, 7% titanium dioxide, 10% spinel, 12% kaolin powder, and 1% silica powder.

[0023] The method for preparing a high temperature resistant and high load softening point refractory brick described in this embodiment is the same as the method for preparing in embodiment 1. The high temperature resistant and high load softening point refractory brick produced in this embodiment has a softening point temperature of 1796.4°C after testing.

[0024] It can be seen from the above three embodiments that spinel and other chemical components play an important role in improving the softening point of refractory bricks. The present invention effectively improves the softening point of refractory bricks by adding spinel, calcium aluminate cement, titanium dioxide and other chemical materials, and makes them have the characteristics of high temperature resistance and high load.

[0025] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A high temperature resistant and high load softening point refractory brick, characterized by: The high temperature resistant and high load softening point refractory bricks comprise, from the outside to the inside, a thermal insulation layer (1) and a fireproof layer (2), a supporting grid (3) is arranged between the thermal insulation layer (1) and the fireproof layer (2), and the fireproof layer (2) comprises the following raw materials in percentage by weight: 48%-80% of large particles of high alumina clinker, 3%-5% of calcium aluminate cement, 5%-10% of titanium dioxide, 6%-10% of spinel, 5%-14% of kaolin powder, and 1%-3% of silica powder.

2. The high temperature resistant and high load softening point refractory brick according to claim 1, characterized in that: The refractory bricks contain 70% of the large particles of high-alumina clinker, 4% of calcium aluminate cement, 6% of titanium dioxide, 8% of spinel, 10% of kaolin powder and 2% of silica fume.

3. The high temperature resistant and high load softening point refractory brick according to claim 1, characterized in that: The particle size of the large particles of high-alumina clinker is 1-2 mm.

4. The high temperature resistant and high load softening point refractory brick according to claim 1, characterized in that: The particle size of the kaolin powder is less than 0.043 mm.

5. The high temperature resistant and high load softening point refractory brick according to claim 1, characterized in that The thickness of the thermal insulation layer (1) is half the thickness of the fireproof layer (2).

6. The high temperature resistant and high load softening point refractory brick according to claim 1, characterized in that The support grid (3) is made of a high temperature resistant rigid material.

7. The present invention provides a method for preparing high temperature resistant and high load softening point refractory bricks, comprising the following steps: S1: Screening large particles of high-alumina clinker and kaolin powder to appropriate sizes; S2: Mix and knead the raw materials according to the proportion; S3: filling the mixed raw materials into a mold and shaping them to obtain fireproof layer bricks; S4: adding a layer of supporting grid on the obtained fireproof layer brick; S5: pre-sintering the fireproof layer bricks and the supporting grid at 80°C-95°C to obtain unfired bricks, drying for 24-36 hours, and finally calcining at 1300-1500°C for 5-12 hours to obtain bricks; S6: pouring a thermal insulation layer on the surface of the brick, placing it in a mold to shape it, and obtaining a refractory brick; S7: calcining the refractory brick blanks at 1500-1700° C. to obtain high temperature resistant and high load softening point refractory bricks; S8: Inspection and analysis of high temperature resistant and high load softening point refractory bricks.

8. The method for preparing high temperature resistant and high load softening point refractory bricks according to claim 7, characterized in that: In step S6, the lower end of the support grid (3) is fixedly connected to the fireproof layer bricks, and the upper end of the support grid is fixedly connected to the thermal insulation layer (1).

9. The method for preparing high temperature resistant and high load softening point refractory bricks according to claim 7, characterized in that: In step S5, the heating rate and cooling rate during the calcination process are controlled at 50-80° C. per hour.

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