High-temperature-resistant mica brick and preparation method thereof
By using raw materials such as coal gangue to prepare high-temperature mica bricks, the problems of short service life and high cost in high temperature environments are solved, and the effects of high volume density, good high temperature performance and long-term stable operation are achieved.
Patent Information
- Application Number
- CN202411713553.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-02-28
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing magnesium and carbonaceous refractory bricks have short service life, high cost, high construction and use environment in high temperature and high corrosion environments, and are susceptible to water reactions, resulting in swelling and cracking of the bricks.
High-temperature resistant mica bricks are prepared using raw materials such as gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks. Through scientific material formulation and innovative sintering process, the bulk density and high-temperature performance of the material are improved.
The prepared high-temperature resistant mica bricks have high volume density, room temperature pressure resistance strength greater than 400MPa, 1000℃ high temperature fold resistance strength more than 80MPa, and fire resistance higher than 1200℃, adapting to a wide range of high temperature and harsh environments and extending the service life of the equipment.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of refractory bricks, and in particular to a high temperature resistant mica brick and a preparation method thereof. Background Art
[0002] In the existing high-titanium slag smelting technology, the high-titanium slag smelting furnace has to withstand a high-temperature, highly corrosive and highly chemically reactive environment. Therefore, the requirements for the furnace lining materials are extremely strict. Magnesium and carbon refractory materials are usually used as furnace lining materials. Magnesium refractory materials are usually used in the working layer of high-titanium slag smelting furnaces due to their high refractoriness, thermal shock resistance and erosion resistance, while carbonaceous materials are used in other parts to provide insulation due to their good thermal conductivity and thermal shock resistance. However, these materials are expensive and sensitive to the construction and use environment. For example, magnesia refractory bricks react easily when in contact with water, causing the brick body to bulge and crack. At the same time, improper construction operations and baking processes may also cause damage to refractory bricks and shorten their service life, requiring more costs for frequent repairs and replacements during the application process.
[0003] Synthetic mica is a man-made material designed to mimic the properties of natural mica while overcoming the limitations of natural mica in purity and performance consistency. Synthetic mica has excellent high temperature resistance, good electrical insulation, chemical stability, thermal stability and thermal shock resistance, and is expected to replace traditional magnesium and carbon refractory bricks. Coal gangue is a solid waste generated during coal mining and washing. Its main components include silicon dioxide (SiO2) and aluminum oxide (Al2O3), which makes coal gangue a potential silicon and aluminum resource. Using coal gangue as a raw material for refractory materials to replace part of the silicon and aluminum in synthetic mica raw materials will not only help recycle resources, but also reduce production costs. Summary of the invention
[0004] In view of this, the object of the present invention is to provide a high temperature resistant mica brick and a preparation method thereof, so as to provide a synthetic mica brick to replace the existing magnesia or carbonaceous refractory bricks.
[0005] Based on the above purpose, the present invention provides a high temperature resistant mica brick, which is prepared from the following raw materials by weight: 20-30 parts of coal gangue, 20-30 parts of quartz sand, 5-7 parts of Al2O3, 26-33 parts of MgO, 22-27 parts of K2SiF6 and 1-5 parts of straw.
[0006] Preferably, it is prepared from the following raw materials, by weight: 24 parts of coal gangue, 24 parts of quartz sand, 6 parts of Al2O3, 29 parts of MgO, 25 parts of K2SiF6 and 3 parts of straw.
[0007] Preferably, the SiO2 content in the coal gangue is higher than 50wt%, and the Al2O3 content is higher than 35wt%.
[0008] Preferably, the coal gangue is 60-100 mesh, the quartz sand is 60-100 mesh, the Al2O3 is 40-80 mesh, the MgO is 40-80 mesh, the K2SiF6 is 40-80 mesh, and the straw is 80-120 mesh.
[0009] Preferably, the straw is one or a mixture of corn straw, rice straw, sugarcane straw and wheat straw.
[0010] Preferably, the weight of the coal gangue is 1 times the weight of the quartz sand.
[0011] Furthermore, the present invention also provides a method for preparing a high temperature resistant mica brick, comprising the following steps:
[0012] (1) adding coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn straw into a ball mill, and passing through a 180-220 mesh sieve after ball milling to obtain a mixed powder;
[0013] (2) The mixed powder is added into a sintering furnace, and after gradient sintering, the temperature is cooled to room temperature, and a water jet is used for cutting to obtain a high temperature resistant mica brick.
[0014] Preferably, the gradient sintering in step (2) is to heat the material from room temperature to 550-650°C at a heating rate of 4-6°C / min, keep the temperature for 1.5-2.5h, then heat the material from 550-650°C to 1000-1100°C at a heating rate of 0.5-2°C / min, and keep the temperature for 4-6h.
[0015] Preferably, the cooling rate is 8-12°C / min.
[0016] Beneficial effects of the present invention:
[0017] The high temperature resistant mica brick of the present invention has a high volume density, a compressive strength of more than 400MPa at room temperature, a flexural strength of more than 80MPa at a high temperature of 1000°C, and a refractoriness of more than 1200°C through a scientific material formula and an innovative sintering process. This series of excellent properties ensures that the material can operate stably for a long time under a wide range of conditions including high temperature and harsh environment, and improves the stability and service life of equipment in industrial applications.
[0018] The present invention uses coal gangue to replace part of the quartz sand to effectively improve the folding resistance of the material at high temperature and enhance the adaptability of mica bricks in high-temperature applications. However, complete replacement will cause performance degradation due to impurities, and the ratio needs to be optimized. In addition, adding a small amount of corn stalks can form tiny pores during the sintering process. These pores help release residual stress, thereby improving the room temperature compressive strength and high temperature folding strength, demonstrating the flexibility and adjustment potential of the process.
[0019] The present invention optimizes the sintering process, especially the heat treatment at 600°C, which not only promotes the formation of pores, but also helps to remove unnecessary impurities in the coal gangue. The low-temperature sintering conditions limit the crystal growth mode of mica, forming fine particles, further enhancing the uniformity and density of the material. DETAILED DESCRIPTION
[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.
[0021] The composition of the coal gangue used in the examples and comparative examples of the present invention is shown in Table 1;
[0022] Table 1 Composition of coal gangue
[0023]
[0024] Example 1: The following steps were used for preparation, and the raw materials used were shown in Table 2:
[0025] Table 2 Raw materials of Example 1
[0026] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 24 24 6 29 25 3
[0027] The specific preparation steps are as follows:
[0028] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 2, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0029] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. The temperature was then increased from 600°C to 1050°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The high temperature resistant mica bricks were cut by a water jet.
[0030] Example 2: Prepared by the following steps, the raw materials used are shown in Table 3:
[0031] Table 3 Raw materials of Example 2
[0032] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 20 20 5 26 22 1
[0033] The specific preparation steps are as follows:
[0034] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 3, and pass through a 180-mesh sieve after ball milling to obtain a mixed powder;
[0035] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 550°C at a heating rate of 4°C / min, and kept at this temperature for 1.5 h. The temperature was then increased from 550°C to 1000°C at a heating rate of 0.5°C / min, and kept at this temperature for 4 h. The temperature was then decreased from 1000°C to room temperature at a cooling rate of 10°C / min. The high temperature resistant mica bricks were cut by a water jet.
[0036] Example 3: The following steps were used for preparation, and the raw materials used were shown in Table 4:
[0037] Table 4 Raw materials of Example 3
[0038] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 30 30 7 33 27 5
[0039] The specific preparation steps are as follows:
[0040] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 4, and pass through a 220-mesh sieve after ball milling to obtain a mixed powder;
[0041] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 650°C at a heating rate of 6°C / min, and kept at this temperature for 2.5 h. The temperature was then increased from 650°C to 1100°C at a heating rate of 2°C / min, and kept at this temperature for 6 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The high temperature resistant mica bricks were cut by a water jet.
[0042] Comparative Example 1:
[0043] The difference between Comparative Example 1 and Example 1 is that the raw material does not contain coal gangue.
[0044] The following steps were used for preparation, and the raw materials used are shown in Table 5:
[0045] Table 5 Raw materials list of comparative example 1
[0046] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 0 37 15 29 25 3
[0047] The specific preparation steps are as follows:
[0048] (1) Add quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 5, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0049] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. The temperature was then increased from 600°C to 1050°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The mica bricks were cut by a water jet.
[0050] Comparative Example 2:
[0051] The difference between Comparative Example 2 and Example 1 is that the raw material does not contain quartz sand;
[0052] The following steps were used for preparation, and the raw materials used are shown in Table 6:
[0053] Table 6 Raw materials list of comparative example 2
[0054] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 70 0 0 29 25 3
[0055] The specific preparation steps are as follows:
[0056] (1) Add coal gangue, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 6, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0057] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. The temperature was then increased from 600°C to 1050°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The mica bricks were cut by a water jet.
[0058] Comparative Example 3:
[0059] The difference between Comparative Example 3 and Example 1 is that the raw material does not contain corn stalks;
[0060] The following steps were used for preparation, and the raw materials used are shown in Table 7:
[0061] Table 7 Raw materials list of comparative example 3
[0062] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 24 24 6 29 25 0
[0063] The specific preparation steps are as follows:
[0064] (1) Add coal gangue, quartz sand, Al2O3, MgO and K2SiF6 into a ball mill according to the raw material dosage in Table 2, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0065] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. The temperature was then increased from 600°C to 1050°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The mica bricks were cut by a water jet.
[0066] Comparative Example 4:
[0067] The difference between Comparative Example 4 and Example 1 is that the amount of corn stalks used in the raw material is 10 kg;
[0068] The following steps were used for preparation, and the raw materials used are shown in Table 8:
[0069] Table 8 Raw materials list of comparative example 4
[0070]
[0071]
[0072] The specific preparation steps are as follows:
[0073] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 8, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0074] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. The temperature was then increased from 600°C to 1050°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. The temperature was then decreased from 1050°C to room temperature at a cooling rate of 10°C / min. The mica bricks were cut by a water jet.
[0075] Comparative Example 5:
[0076] The difference between Comparative Example 5 and Example 1 is that the temperature is directly increased from room temperature to 1050°C at a heating rate of 5°C / min;
[0077] The following steps were used for preparation, and the raw materials used are shown in Table 9:
[0078] Table 9 Raw materials list of comparative example 5
[0079] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 24 24 6 29 25 3
[0080] The specific preparation steps are as follows:
[0081] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 9, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0082] (2) The mixed powder was added into a sintering furnace, and the temperature was increased from room temperature to 1050°C at a heating rate of 5°C / min, and kept at this temperature for 5 h. Then, the temperature was decreased from 1050°C to room temperature at a cooling rate of 10°C / min, and the mica bricks were obtained by water jet cutting.
[0083] Comparative Example 6:
[0084] The difference between Comparative Example 6 and Example 1 is that the temperature is raised from room temperature to 600°C at a heating rate of 5°C / min, kept at that temperature for 2 hours, and then raised from 600°C to 1400°C at a heating rate of 1°C / min, kept at that temperature for 5 hours;
[0085] The following steps were used for preparation, and the raw materials used are shown in Table 10:
[0086] Table 10 Raw materials list of comparative example 6
[0087] raw material Coal Gangue Quartz sand <![CDATA[Al2O3]]> MgO <![CDATA[K2SiF6]]> Corn stalks Number of mesh / mesh 80 120 60 60 60 100 Dosage / kg 24 24 6 29 25 3
[0088] The specific preparation steps are as follows:
[0089] (1) Add coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn stalks into a ball mill according to the raw material dosage in Table 10, and pass through a 200-mesh sieve after ball milling to obtain a mixed powder;
[0090] (2) The mixed powder is added into a sintering furnace, and the temperature is increased from room temperature to 600°C at a heating rate of 5°C / min, and kept at this temperature for 2 h. Then, the temperature is increased from 600°C to 1400°C at a heating rate of 1°C / min, and kept at this temperature for 5 h. Then, the temperature is decreased from 1400°C to room temperature at a cooling rate of 10°C / min, and the mica bricks are cut by a water jet.
[0091] Performance Test:
[0092] The bulk density is tested according to GB / T2998-2001, the compressive strength at room temperature is tested according to GB / T 5072-2008, the high temperature flexural strength is tested according to GB / T3002-2017, and the refractoriness is tested by the cone method. The specific results are shown in Table 11.
[0093] Table 1 Performance test results
[0094]
[0095]
[0096] Data Analysis:
[0097] From the data of Examples 1-3 in Table 11, it can be seen that the high temperature resistant mica brick prepared by the present invention has a high volume density, a room temperature compressive strength of more than 400MPa, a 1000℃ high temperature flexural strength of more than 80MPa, and a refractoriness higher than 1200℃. The high temperature resistant mica brick of the present invention significantly improves its physical properties through optimized material formula and process, not only meets the requirements of pressure resistance and flexural resistance, but also adapts to long-term use in harsh environments. This brick can greatly improve the operating stability and life of high temperature equipment, and provide a more reliable material choice for industrial production.
[0098] It can be seen from the data of Example 1 and Comparative Example 1 in Table 11 that using coal gangue to replace part of the quartz sand does not reduce the physical properties of the mica brick, but instead improves the high-temperature flexural strength at 1000°C, making it more suitable for use in high-temperature environments.
[0099] It can be seen from the data of comparative example 2 of embodiment 1 in Table 11 that completely replacing quartz sand with coal gangue will reduce the physical properties of mica bricks. This is mainly due to the influence of impurities such as carbon and organic matter in the coal gangue, which makes the matrix structure loose.
[0100] It can be seen from the data of Example 1 and Comparative Example 3 in Table 11 that the addition of a small amount of corn straw will slightly reduce the volume density of the mica brick, but improve the room temperature compressive strength and 1000°C high temperature flexural strength. This is because the tiny pores generated by a small amount of corn straw during the sintering process release the residual stress.
[0101] It can be seen from the data of Example 1 and Comparative Example 4 in Table 11 that the addition of a large amount of corn straw will significantly reduce the physical properties of mica bricks, which is mainly due to the large number of pores affecting the density of mica bricks.
[0102] It can be seen from the data of Example 1 and Comparative Examples 5-6 in Table 11 that the sintering method of the present invention helps to improve the physical properties of mica bricks. This is because the insulation at 600°C helps the corn stalks to generate tiny pores, and helps to release residual stress in the later stage, while helping to remove impurities such as carbon and organic matter in the coal gangue. In addition, the lower sintering temperature helps to prevent the mica from growing into large sheets of layered mica during the crystallization process, and can only form crystalline fine particles. This fine particle structure helps to improve the density and uniformity of the material, thereby enhancing the overall strength of the mica brick.
[0103] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.
Claims
1. A high temperature resistant mica brick, characterized in that: The invention is prepared from the following raw materials by weight: 20-30 parts of coal gangue, 20-30 parts of quartz sand, 5-7 parts of Al2O3, 26-33 parts of MgO, 22-27 parts of K2SiF6 and 1-5 parts of straw.
2. The high temperature resistant mica brick according to claim 1, characterized in that: The raw materials are as follows: 24 parts of coal gangue, 24 parts of quartz sand, 6 parts of Al2O3, 29 parts of MgO, 25 parts of K2SiF6 and 3 parts of straw.
3. The high temperature resistant mica brick according to claim 1, characterized in that: The coal gangue has a SiO2 content higher than 50wt%, and an Al2O3 content higher than 35wt%.
4. The high temperature resistant mica brick according to claim 1, characterized in that: The coal gangue is 60-100 mesh, the quartz sand is 60-100 mesh, the Al2O3 is 40-80 mesh, the MgO is 40-80 mesh, the K2SiF6 is 40-80 mesh, and the straw is 80-120 mesh.
5. The high temperature resistant mica brick according to claim 1, characterized in that: The straw is one of corn straw, rice straw, sugarcane straw and wheat straw, or a mixture of several of them.
6. The high temperature resistant mica brick according to claim 1, characterized in that: The weight of the coal gangue is 1 times the weight of the quartz sand.
7. A method for preparing high temperature resistant mica bricks according to claim 1, characterized in that: The following steps are involved: (1) adding coal gangue, quartz sand, Al2O3, MgO, K2SiF6 and corn straw into a ball mill, and passing through a 180-220 mesh sieve after ball milling to obtain a mixed powder; (2) The mixed powder is added into a sintering furnace, and after gradient sintering, the temperature is cooled to room temperature, and a water jet is used for cutting to obtain a high temperature resistant mica brick.
8. The method for preparing high temperature resistant mica bricks according to claim 7, characterized in that: In the step (2), the gradient sintering is to heat the material from room temperature to 550-650°C at a heating rate of 4-6°C / min, keep the temperature for 1.5-2.5h, and then heat the material from 550-650°C to 1000-1100°C at a heating rate of 0.5-2°C / min, and keep the temperature for 4-6h.
9. The method for preparing high temperature resistant mica bricks according to claim 7, characterized in that: The cooling rate is 8-12°C / min.