A fire resistant aluminium silicate blanket and a method of making the same

Abstract

This invention relates to the field of refractory materials technology, and proposes a refractory aluminosilicate blanket and its preparation method. The refractory aluminosilicate blanket uses calcined coal gangue and calcined kaolin as raw materials. The calcined coal gangue is composed of the following components: calcined coal gangue with a particle size of 0.5mm ≤ < 3mm, calcined coal gangue with a particle size of 3mm ≤ < 6mm, calcined coal gangue with a particle size of 6mm ≤ < 10mm, calcined coal gangue with a particle size of 10mm ≤ < 15mm, and calcined coal gangue with a particle size of 15mm ≤ < 20mm. The calcined kaolin is composed of the following components: calcined kaolin with a particle size of 0.5mm ≤ < 3mm, calcined kaolin with a particle size of 3mm ≤ < 6mm, calcined kaolin with a particle size of 6mm ≤ < 10mm, calcined kaolin with a particle size of 10mm ≤ < 15mm, and calcined kaolin with a particle size of 15mm ≤ < 20mm. The above solution solves the problems of low tensile strength and high slag ball content in the related technologies of aluminosilicate blankets.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a refractory aluminosilicate blanket and its preparation method. Background Technology

[0002] Aluminosilicate fibers possess advantages such as high temperature resistance, good thermal stability, low thermal conductivity, small heat capacity, low thermal expansion, and good thermal insulation properties, making them suitable for the manufacture of refractory blankets. Refractory aluminosilicate blankets are refractory fiber products made from aluminosilicate fibers using a dry needle-punching process. They are primarily used for lining high-temperature industrial furnaces and covering high-temperature pipelines.

[0003] The properties of aluminosilicate fibers directly determine the properties of aluminosilicate blankets. Traditional raw materials for preparing aluminosilicate fibers include calcined alumina and kaolin, but the resulting aluminosilicate fibers have low tensile strength and high slag content, leading to low tensile strength and high slag content in the processed aluminosilicate blankets. Summary of the Invention

[0004] This invention proposes a refractory aluminosilicate blanket and its preparation method, which solves the problems of low tensile strength and high slag ball content in related technologies.

[0005] The technical solution of the present invention is as follows: A refractory aluminosilicate blanket, the raw materials of which include calcined coal gangue and calcined kaolin; The calcined coal gangue is composed of the following components by mass percentage: 3%~7% calcined coal gangue with a particle size of 0.5mm ≤ <3mm, 50%~55% calcined coal gangue with a particle size of 3mm ≤ <6mm, 3%~7% calcined coal gangue with a particle size of 6mm ≤ <10mm, 30%~35% calcined coal gangue with a particle size of 10mm ≤ <15mm, and the balance being calcined coal gangue with a particle size of 15mm ≤ <20mm. The calcined kaolin is composed of the following components by mass percentage: 10%~15% calcined kaolin with a particle size of 0.5mm ≤ <3mm, 15%~20% calcined kaolin with a particle size of 3mm ≤ <6mm, 50%~55% calcined kaolin with a particle size of 6mm ≤ <10mm, 10%~15% calcined kaolin with a particle size of 10mm ≤ <15mm, and the balance being calcined kaolin with a particle size of 15mm ≤ <20mm.

[0006] Coal gangue is a waste that is difficult to biodegrade naturally, and direct stockpiling would occupy a large amount of land and cause environmental pollution. This invention uses calcined coal gangue as part of the raw material for aluminosilicate blankets, realizing the resource utilization of solid waste. The calcined kaolin contains a high proportion of active SiO2 and Al2O3, and has an ideal chemical composition in the high-temperature molten state, enabling the formation of structurally stable aluminosilicate fibers, laying the foundation for the excellent performance of the aluminosilicate blankets. The mass ratio of calcined coal gangue to calcined kaolin can be any conventional ratio in the art, for example, 8:2 to 7:3, preferably 7:3.

[0007] As a further technical solution, the calcination temperature of the calcined coal gangue with a particle size <10mm is 850~950℃, and the calcination temperature of the calcined coal gangue with a particle size ≥10mm is 750~800℃.

[0008] As a further technical solution, the calcination temperature of the calcined kaolin with a particle size <10mm is 750~800℃, and the calcination temperature of the calcined kaolin with a particle size ≥10mm is 700℃.

[0009] In this invention, coal gangue and kaolin with high calcination temperature are used as small-particle-size raw materials, while coal gangue and kaolin with low calcination temperature are used as large-particle-size raw materials. This further improves the tensile strength of the aluminosilicate blanket and further reduces the slag ball content.

[0010] This invention also proposes a method for preparing a refractory aluminosilicate blanket, comprising the following steps: S1. After mixing calcined coal gangue and calcined kaolin, melt them, centrifuge and spin them into fibers to obtain aluminum silicate fibers; S2. Spray softening liquid onto the surface of the aluminosilicate fiber, collect cotton, needle punch, and heat set to obtain a refractory aluminosilicate blanket.

[0011] The specific preparation method is as follows: Calcined coal gangue and calcined kaolin are transported to the feeding port of the electric resistance furnace using a conveyor belt. The amount of calcined coal gangue and calcined kaolin added is controlled by controlling the conveyor belt speed. After the two raw materials are put into the electric resistance furnace, they are melted by the current generated between the resistors. During the melting process, circulating cooling water is used to prevent the temperature of the electric resistance furnace from getting too high. The melt flows out from the bottom of the electric resistance furnace and enters the spinning machine. Under the action of a high-speed centrifuge, fibers are formed to obtain aluminosilicate fibers. A softening liquid is sprayed on the surface of the aluminosilicate fibers using a sprayer. After being transferred to a cotton collector for cotton collection, the fibers are needled by a needle punching machine. Then, they are heat-set and cured, and cut longitudinally and transversely to obtain refractory aluminosilicate blankets.

[0012] As a further technical solution, the melting temperature is 1800~2000℃ and the melting time is 1.5~2h.

[0013] As a further technical solution, the rotation speed of the centrifugal spinning is 9000~12000 rpm.

[0014] As a further technical solution, the softening liquid is composed of water and softening agent in a mass ratio of 7~9:1; the amount of softening liquid used is 5~10 kg / t based on the weight of aluminum silicate fiber.

[0015] Newly produced aluminosilicate fibers are hard and require the addition of a softener to make them more flexible before further processing. The softener can be any conventional softener in the field, but is preferably the aluminosilicate needled blanket softener from KST Lubrication Technology Co., Ltd.

[0016] As a further technical solution, the frequency of the acupuncture is 60-90 times / min.

[0017] In the needle punching machine, the up-and-down movement of the needle hook drives the fibers. The movement frequency of the needle hook is 60~90 times / min, which makes the cotton fiber layers tightly interwoven, providing the aluminosilicate blanket with a certain tensile strength and wind erosion resistance.

[0018] As a further technical solution, the heat setting temperature is 500~600℃ and the time is 15~25min.

[0019] The working principle and beneficial effects of this invention are as follows: This invention involves particle size distribution and control of calcined coal gangue and calcined kaolin, which increases the bulk density of the raw material mixture, reduces the porosity during the mixing process, and ensures uniform heating of the raw materials during melting. Controlling the proportion of small-sized (0.5~3mm) and large-sized (15~20mm) raw materials avoids both excessive melting and agglomeration, as well as insufficient melting, which leads to the formation of "slag balls". It also helps with stretching and solidification during the spinning process, resulting in fibers with better continuity and fewer defects. This achieves the effect of improving the tensile strength of aluminosilicate blankets and reducing the slag ball content. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In the following embodiments and comparative examples: Coal gangue: 45.02 wt% silica, 34.7 wt% alumina, 0.222 wt% iron oxide, 0.599 wt% titanium dioxide, 0.0857 wt% calcium oxide, and 0.0915 wt% magnesium oxide; Kaolin: 54.01 wt% silica, 41.43 wt% alumina, 0.89 wt% iron oxide, 0.21 wt% calcium oxide, 0.23 wt% magnesium oxide, 0.22 wt% potassium oxide, 0.61 wt% titanium dioxide, and 0.06 wt% sodium oxide; Softener: Softener specifically for aluminum silicate needled blankets, purchased from KST Lubrication Technology Co., Ltd.

[0022] Example 1 A refractory aluminosilicate blanket, the raw materials of which include calcined coal gangue and calcined kaolin in a mass ratio of 7:3; Calcined coal gangue is obtained by calcining coal gangue at 950℃ for 50 minutes; calcined kaolin is obtained by calcining kaolin at 800℃ for 90 minutes. Calcined coal gangue is composed of the following components by mass percentage: 3% calcined coal gangue with a particle size of 0.5mm ≤ < 3mm, 50% calcined coal gangue with a particle size of 3mm ≤ < 6mm, 7% calcined coal gangue with a particle size of 6mm ≤ < 10mm, 35% calcined coal gangue with a particle size of 10mm ≤ < 15mm, and the balance being calcined coal gangue with a particle size of 15mm ≤ < 20mm. Calcined kaolin is composed of the following components by mass percentage: 10% calcined kaolin with a particle size of 0.5mm ≤ < 3mm, 15% calcined kaolin with a particle size of 3mm ≤ < 6mm, 55% calcined kaolin with a particle size of 6mm ≤ < 10mm, 15% calcined kaolin with a particle size of 10mm ≤ < 15mm, and the balance being calcined kaolin with a particle size of 15mm ≤ < 20mm. It is prepared by the following method: S1. After mixing calcined coal gangue and calcined kaolin evenly, melt at 2000℃ for 1.5h, and centrifuge at 10000rpm to obtain aluminum silicate fibers. S2. Spray softening liquid onto the surface of aluminosilicate fibers. The amount of softening liquid used in each ton of alumina fibers is 10 kg. The softening liquid is composed of water and softening agent in a mass ratio of 9:1. Collect the fibers and perform needle punching at a frequency of 90 times / min. Heat set at 600℃ for 15 min. Cut longitudinally and transversely to obtain a refractory aluminosilicate blanket with a length of 3600 mm × width of 610 mm × thickness of 50 mm.

[0023] Example 2 A refractory aluminosilicate blanket, the raw materials of which include calcined coal gangue and calcined kaolin in a mass ratio of 7:3; Calcined coal gangue is obtained by calcining coal gangue at 950℃ for 50 minutes; calcined kaolin is obtained by calcining kaolin at 800℃ for 90 minutes. Calcined coal gangue is composed of the following components by mass percentage: 7% calcined coal gangue with a particle size of 0.5mm ≤ < 3mm, 55% calcined coal gangue with a particle size of 3mm ≤ < 6mm, 3% calcined coal gangue with a particle size of 6mm ≤ < 10mm, 30% calcined coal gangue with a particle size of 10mm ≤ < 15mm, and the balance being calcined coal gangue with a particle size of 15mm ≤ < 20mm. Calcined kaolin is composed of the following components by mass percentage: 15% calcined kaolin with a particle size of 0.5mm ≤ < 3mm, 20% calcined kaolin with a particle size of 3mm ≤ < 6mm, 50% calcined kaolin with a particle size of 6mm ≤ < 10mm, 10% calcined kaolin with a particle size of 10mm ≤ < 15mm, and the balance being calcined kaolin with a particle size of 15mm ≤ < 20mm. It is prepared by the following method: S1. After mixing calcined coal gangue and calcined kaolin evenly, melt at 1800℃ for 2 hours, and centrifuge and spin at 12000 rpm to obtain aluminum silicate fibers. S2. Spray softening liquid onto the surface of aluminosilicate fibers. The amount of softening liquid used in each ton of alumina fibers is 5 kg. The softening liquid is composed of water and softening agent in a mass ratio of 7:1. Collect the fibers and perform needle punching at a frequency of 60 times / min. Heat set at 500℃ for 25 min. Cut longitudinally and transversely to obtain a refractory aluminosilicate blanket with a length of 3600mm × width of 610mm × thickness of 50mm.

[0024] Example 3 The only difference from Example 1 is: Calcined coal gangue is obtained by calcining coal gangue at 800℃ for 50 minutes; calcined kaolin is obtained by calcining kaolin at 700℃ for 90 minutes.

[0025] Example 4 The only difference from Example 1 is: Calcined coal gangue with a particle size <10mm is obtained by calcining coal gangue at 800℃ for 50min, and calcined coal gangue with a particle size ≥10mm is obtained by calcining coal gangue at 950℃ for 50min. Calcined kaolin with a particle size <10mm is obtained by calcining kaolin at 700℃ for 90min, and calcined kaolin with a particle size ≥10mm is obtained by calcining kaolin at 800℃ for 90min.

[0026] Example 5 The only difference from Example 1 is: Calcined coal gangue with a particle size <10mm is obtained by calcining coal gangue at 950℃ for 50min, and calcined coal gangue with a particle size ≥10mm is obtained by calcining coal gangue at 800℃ for 50min. Calcined kaolin with a particle size <10mm is obtained by calcining kaolin at 800℃ for 90min, and calcined kaolin with a particle size ≥10mm is obtained by calcining kaolin at 700℃ for 90min.

[0027] Example 6 The only difference from Example 2 is that: Calcined coal gangue with a particle size <10mm is obtained by calcining coal gangue at 850℃ for 50min, and calcined coal gangue with a particle size ≥10mm is obtained by calcining coal gangue at 750℃ for 50min. Calcined kaolin with a particle size <10mm is obtained by calcining kaolin at 750℃ for 90min, and calcined kaolin with a particle size ≥10mm is obtained by calcining kaolin at 700℃ for 90min.

[0028] Comparative Example 1 The only difference from Example 1 is: Calcined coal gangue is composed of the following components by mass percentage: 30% calcined coal gangue with a particle size of 0 < ≤ 2 mm and 70% calcined coal gangue with a particle size of 2 mm < ≤ 5 mm; Calcined kaolin is composed of the following components by mass percentage: 30% calcined kaolin with a particle size of 0 < ≤ 2 mm and 70% calcined kaolin with a particle size of 2 mm < ≤ 5 mm.

[0029] Comparative Example 2 The only difference from Example 1 is: Calcined coal gangue is composed of the following components by mass percentage: 10% calcined coal gangue with a particle size of 0.5mm ≤ < 3mm, 15% calcined coal gangue with a particle size of 3mm ≤ < 6mm, 55% calcined coal gangue with a particle size of 6mm ≤ < 10mm, 15% calcined coal gangue with a particle size of 10mm ≤ < 15mm, and the balance being calcined coal gangue with a particle size of 15mm ≤ < 20mm. Calcined kaolin is composed of the following components by mass percentage: 3% calcined kaolin with a particle size of 0.5mm ≤ < 3mm, 50% calcined kaolin with a particle size of 3mm ≤ < 6mm, 7% calcined kaolin with a particle size of 6mm ≤ < 10mm, 35% calcined kaolin with a particle size of 10mm ≤ < 15mm, and the balance being calcined kaolin with a particle size of 15mm ≤ < 20mm.

[0030] Comparative Example 3 The only difference from Example 1 is: Calcined coal gangue is composed of the following components by mass percentage: 30% calcined coal gangue with a particle size <6mm, 50% calcined coal gangue with a particle size ≤6mm and <10mm, and the balance being calcined coal gangue with a particle size ≥10mm. Calcined kaolin is composed of the following components by mass percentage: 30% calcined kaolin with a particle size <6mm, 50% calcined kaolin with a particle size ≤6mm and <10mm, and the balance being calcined kaolin with a particle size ≥10mm.

[0031] Performance testing: (1) Slag ball content: The slag ball content (particle size > 0.212 mm) was tested according to the method in GB / T 5480-2017. The separation process (dry method) was as follows: the pressed sample was taken out and placed directly into the sample sieve. Mechanical vibration was used until all the fibers passed through the sieve and the remaining slag balls were removed. (2) Tensile strength: The tensile strength shall be tested in accordance with the method in GB / T 17911-2018; The test results are recorded in Table 1.

[0032] Table 1. Slag ball content and tensile strength test results of aluminosilicate blankets

[0033] As can be seen from Table 1, compared with Comparative Examples 1-3, the aluminosilicate blankets obtained in Examples 1-6 have lower slag ball content and higher tensile strength. This indicates that the present invention improves the tensile strength of the aluminosilicate blanket by grading the particle size distribution of calcined coal gangue and calcined kaolin and controlling the content of each particle size distribution, while reducing the slag ball content.

[0034] Furthermore, the aluminosilicate blankets obtained in Examples 1-6 have smooth surfaces without defects such as holes, honeycombs, or visible cracks. The bulk density (GB / T 5480-2017) of the aluminosilicate blanket in Example 1 is 128 kg / m³. 3 The thermal conductivity (GB / T 10294-2008, 500℃) is 0.135W / m·K, and the permanent linear change upon heating (GB / T 17911-2018, 1000℃, 24h, heating method: hot furnace method) is 1.5%, indicating that the aluminosilicate blanket provided by this invention has good fire resistance.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fire resistant aluminum silicate blanket characterized by, The raw materials include calcined coal gangue and calcined kaolin; The calcined coal gangue is composed of the following components by mass percentage: 3%~7% calcined coal gangue with a particle size of 0.5mm ≤ <3mm, 50%~55% calcined coal gangue with a particle size of 3mm ≤ <6mm, 3%~7% calcined coal gangue with a particle size of 6mm ≤ <10mm, 30%~35% calcined coal gangue with a particle size of 10mm ≤ <15mm, and the balance being calcined coal gangue with a particle size of 15mm ≤ <20mm. The calcined kaolin is composed of the following components by mass percentage: 10%~15% calcined kaolin with a particle size of 0.5mm ≤ <3mm, 15%~20% calcined kaolin with a particle size of 3mm ≤ <6mm, 50%~55% calcined kaolin with a particle size of 6mm ≤ <10mm, 10%~15% calcined kaolin with a particle size of 10mm ≤ <15mm, and the balance being calcined kaolin with a particle size of 15mm ≤ <20mm.

2. A fire resistant aluminium silicate blanket according to claim 1, characterised in that, The calcination temperature of the calcined coal gangue with a particle size <10mm is 850~950℃, and the calcination temperature of the calcined coal gangue with a particle size ≥10mm is 750~800℃.

3. A fire resistant alumina silica blanket according to claim 1, wherein, The calcination temperature of the calcined kaolin with a particle size <10mm is 750~800℃, and the calcination temperature of the calcined kaolin with a particle size ≥10mm is 700℃.

4. A fire resistant alumina silica blanket according to claim 1, wherein, The mass ratio of calcined coal gangue to calcined kaolin is 7:

3.

5. A method for preparing a refractory aluminosilicate blanket, used to prepare the refractory aluminosilicate blanket according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. After mixing calcined coal gangue and calcined kaolin, melt them, centrifuge and spin them into fibers to obtain aluminum silicate fibers; S2. Spray softening liquid onto the surface of the aluminosilicate fiber, collect cotton, needle punch, and heat set to obtain a refractory aluminosilicate blanket.

6. The method for preparing a refractory aluminosilicate blanket according to claim 5, characterized in that, The melting temperature is 1800~2000℃, and the melting time is 1.5~2h.

7. The method for preparing a refractory aluminosilicate blanket according to claim 5, characterized in that, The centrifugal spinning speed is 9000~12000 rpm.

8. The method for preparing a refractory aluminosilicate blanket according to claim 5, characterized in that, The softening solution is composed of water and softening agent in a mass ratio of 7~9:1; the amount of softening solution used is 5~10 kg / t based on the weight of aluminum silicate fiber.

9. The method for preparing a refractory aluminosilicate blanket according to claim 5, characterized in that, The frequency of the acupuncture is 60-90 times / min.

10. The method for preparing a refractory aluminosilicate blanket according to claim 5, characterized in that, The heat setting temperature is 500~600℃, and the time is 15~25min.

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