Anti-erosion carbon furnace silica brick and preparation method thereof

Abstract

The invention discloses an anti-erosion carbon furnace silica brick and a preparation method thereof, and the anti-erosion carbon furnace silica brick comprises the following raw materials by mass: 20-30 parts of silica sand particles with a particle size of 2.18-1.5 mm; 15-25 parts of silica sand particles with the particle size of 1.5-0.5 mm; 20-30 parts of silica sand particles with the particle size of 0.5-0.1 mm; 3-15 parts of waste brick particles with the particle size of 2.18 mm, and 20-30 parts of silica sand fine powder with the particle size of less than 0.088 mm; 1-5 parts of silica powder; 2-3 parts of calcium hydroxide powder; 1-2 parts of fluorite powder; 1 to 3 parts of pyrophyllite; and 0.8 to 1.5 parts of a binding agent. The invention has the following beneficial effects: in the formula design, a mineralizer iron scale commonly used in traditional coke oven silica bricks and carbon furnace silica bricks is removed, the iron content of the roasted silica bricks is only about 0.3%, the iron content of the silica bricks is natural ore, and the relatively low iron content is beneficial for improving the erosion resistance of the carbon furnace silica bricks.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory material preparation, and particularly relates to an erosion-resistant carbon furnace silica brick and a preparation method thereof. Background Art

[0002] The carbon furnace is the main thermal equipment in the production of carbon products. Silica brick is an important raw material for building carbon furnaces. With the continuous development of modern industry, the continuous progress of science and technology, and the continuous improvement of environmental protection requirements, higher requirements are put forward for the erosion resistance and service life of carbon furnaces. In the actual production process, silica bricks are prone to erosion and damage, thus affecting their service life. The main factors affecting the service life of carbon furnaces are as follows: ① The quality of silica bricks. For example, if the residual quartz content in the bricks is relatively high, crystal form transformation occurs at high temperatures, resulting in brick body deformation or expansion and cracking; ② In addition, during the calcination process, although moisture and volatile components are removed, there is a residual sulfur content, which may also be an inducement for melting and damage. The reason is that silica bricks may be eroded under the action of sulfur, and the higher the sulfur content, the more obvious the erosion effect on silica bricks.

[0003] In the prior art, in view of the above analysis, improvements can be made from the following aspects to improve the service life of silica bricks in carbon furnaces: ① Select high-quality silica raw materials. Specifically, because the purity, density, and quartz crystal content of different quartzites are different, and their transformation speeds are also different during actual use, appropriate selection can be made according to the actual situation; ② Select special composite mineralizers, such as iron scale and clay, and then use the mineralizers and silicon dioxide to form a low-melting-point high-temperature liquid phase to promote the transformation of quartz into tridymite and cristobalite during the transformation process.

[0004] Specifically in the method of ②, although using iron scale and clay as mineralizers can enhance the strength of silica bricks, due to the general lubrication ability of iron scale and clay, there will be a large frictional resistance between the silica bricks and the template during the forming stage, resulting in a general density of the semi-finished blank, and ultimately leading to poor high-temperature performance of the fired product. Summary of the Invention

[0005] The purpose of the present invention is to provide an erosion-resistant carbon furnace silica brick and a preparation method thereof to solve the above problems, as elaborated below.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: An erosion-resistant carbon furnace silica brick provided by the present invention comprises the following raw materials in parts by mass: Among them, 20 - 30 parts of silica sand particles with a particle size of 2.18 - 1.5 mm; 15 - 25 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 20 - 30 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 3 - 15 parts of waste brick particles with a particle size of 2.18 mm; 20 - 30 parts of silica sand fine powder with a particle size < 0.088 mm; 1 - 5 parts of silica powder; 2 - 3 parts of calcium hydroxide powder; 1 - 2 parts of fluorite powder; 1 - 3 parts of pyrophyllite; 0.8 - 1.5 parts of binder.

[0007] Preferably, the chemical formula of the pyrophyllite is Al 2 [Si 4 O 10 (OH) 2 , where by weight: the theoretical content of Al 2 O 3 is 28.3%, SiO 2 is 66.7%, and H 2 O is 5.0%.

[0008] Preferably, the binder is one or a mixture of yellow dextrin, white dextrin and water.

[0009] The preparation method of the above anti - erosion carbon furnace silica brick includes the following steps: S110, dry mixing: Fill silica sand particles with a particle size of 2.18 - 1.5 mm, silica sand particles with a particle size of 1.5 - 0.5 mm, silica sand particles with a particle size of 0.5 - 0.1 mm; waste brick particles with a particle size of 2.18 mm, silica sand fine powder with a particle size < 0.088 mm, silica powder, calcium hydroxide powder, fluorite powder, pyrophyllite and binder into a high - speed mixer according to the raw material ratio, and dry mix for 1 - 3 min; S120, wet mixing: Fill the dry - mixed material into a roller mill equipment, add 4.5 - 6.5% water according to the material amount, and mix for 10 - 20 min to form a mud; S130, brick making: Press the mud into a blank, and send it into a dryer for drying to form a brick blank; S140, firing: Place the dried brick blank in a tunnel kiln for firing, and keep it at a temperature of 1380℃ - 1440℃ for 20 - 30 h after the temperature rises, and then cool it naturally to room temperature with the furnace to obtain the product.

[0010] Preferably, in step S130, the temperature range of the dryer is 60 - 110℃, and the drying duration range is 24 - 48 h.

[0011] Preferably, in step S140, the total firing time of the silica brick is 189 hours, and the holding time in the high-temperature zone is 32 hours.

[0012] The beneficial effects are as follows: 1. In the formulation design of the present invention, the mineralizer iron scale commonly used in traditional coke oven silica bricks and carbon furnace silica bricks is removed. After roasting, the iron content in the silica brick is only about 0.3%, which is the iron impurity content in natural ore. The lower iron content is beneficial to improving the erosion resistance of the carbon furnace silica brick. Thermodynamically, Fe 2 O 3 will react with C at high temperature: 2Fe 2 O 3 +3C = 4Fe + 3CO 2 ↑. The generated Fe reacts with S in the petroleum coke to form Fe 2 S 3 . At the same time, α-Fe 2 0 3 ·H 2 O in the iron oxide can react with H 2 S in the carbon furnace flue at room temperature. Fe 2 O 3 ·H 2 O + 3H 2 S → Fe 2 S 3 ·H 2 O + 3H 2 O. The lower iron content is beneficial to improving the erosion resistance of the carbon furnace silica brick; 2. At the same time, in the formulation design, pyrophyllite is used to replace the traditional mineralizer bentonite or clay. Utilizing the high lubricity and low potassium and sodium chemical properties of pyrophyllite, during the process of pressing the semi-finished silica brick, the friction resistance with the template is reduced, which is beneficial to improving the density of the semi-finished product body. At the same time, it ensures that micropores can be formed after the body is fired, improving the high-temperature performance and erosion resistance of the product, thereby helping to extend the service life of the carbon furnace. Specific Embodiments

[0013] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts fall within the scope protected by the present invention.

[0014] An erosion-resistant carbon furnace silica brick provided by the present invention comprises the following raw materials in parts by mass: Among them, 20-30 parts of silica sand particles with a particle size of 2.18-1.5 mm; 15 - 25 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 20 - 30 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 3 - 15 parts of waste brick particles with a particle size of 2.18 mm; 20 - 30 parts of silica sand fine powder with a particle size < 0.088 mm; 1 - 5 parts of silica powder; 2 - 3 parts of calcium hydroxide powder; 1 - 2 parts of fluorite powder; 1 - 3 parts of pyrophyllite; 0.8 - 1.5 parts of binder.

[0015] For the above - mentioned solution, the following more specific optimizations are carried out. Specifically, the chemical formula of the pyrophyllite is Al 2 [Si 4 O 10 (OH) 2 , in which, by weight: the theoretical content of Al 2 O 3 is 28.3%, SiO 2 is 66.7%, and H 2 O is 5.0%, so as to accurately add pyrophyllite with a suitable chemical specification according to the above parameters. Optionally, the binder is one or more mixtures of yellow dextrin, white dextrin and water. In this way, firstly, it is convenient to obtain the binder easily, and at the same time, since the binder uses industrial raw materials, the procurement cost of the binder is ensured to be low.

[0016] Specifically for the preparation method, a preparation method of erosion - resistant carbon furnace silica brick includes the following steps: S110, dry mixing: Fill silica sand particles with a particle size of 2.18 - 1.5 mm, silica sand particles with a particle size of 1.5 - 0.5 mm, silica sand particles with a particle size of 0.5 - 0.1 mm; waste brick particles with a particle size of 2.18 mm, silica sand fine powder with a particle size < 0.088 mm, silica powder, calcium hydroxide powder, fluorite powder, pyrophyllite and binder into a high - speed mixer according to the raw material ratio, and dry mix for 1 - 3 min; S120, wet mixing: Fill the dry - mixed materials into a roller mill equipment, add 4.5 - 6.5% water according to the amount of materials, and mix for 10 - 20 min to form a mud; S130, blank making: Press the mud into a blank, and send it into a dryer for drying to form a brick blank; S140, Firing: Place the dried brick blanks in a tunnel kiln for firing. Keep them in the tunnel kiln until the temperature rises to 1380°C - 1440°C and then hold for 20 - 30 hours. After firing, let them cool naturally in the furnace to room temperature to obtain the product.

[0017] In the above method, natural silica particles with a critical particle size of 3.5 are used as the aggregate, calcium hydroxide powder and fluorite powder are used as mineralizers, and pyrophyllite and a catalyst are introduced. Sintering is carried out at high temperature. Utilizing the high lubricity and low potassium and sodium chemical properties of pyrophyllite, during the forming process, the frictional resistance with the mold is reduced, which is beneficial to improving the density of the semi-finished product blank. After firing, micro-pores are formed, enhancing the high-temperature performance of the product, thereby increasing the service life of the carbon furnace.

[0018] The following more specific optimizations were carried out for the above preparation method. Specifically, in step S130, the temperature range of the dryer is 60 - 110°C, and the drying duration range is 24 - 48H. Set like this, firstly, it is convenient to ensure that there are reference technical indicators when making silica bricks by the way of the barrel cover clearly knowing the working parameters of the dryer, and at the same time, it is convenient to ensure that the dryer can completely dry the blank. Further optionally, in step S140, the total firing time of the silica brick is 189 hours, and the holding time in the high-temperature zone is 32 hours. The function of setting like this is to ensure that the firing time of the silica brick has a clearly referenceable duration, which is convenient for batch firing of silica bricks.

[0019] Implement and verify according to the following embodiments with the help of this solution. The specific embodiments are as follows: Example 1: It includes the following parts of raw materials: 26 parts of silica sand particles with a particle size of 2.18 - 1.5 mm; 17 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 22 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 30 parts of silica sand fine powder with a particle size < 0.088 mm; 5 parts of waste brick particles with a particle size of 2.18 mm; 3.5 parts of silica powder; 2.3 parts of calcium hydroxide powder; 1.1 parts of fluorite powder; 1.5 parts of pyrophyllite; One or more of yellow dextrin, white dextrin or water are added as binders, and the total addition amount is 1 part.

[0020] Example 2: It includes the following parts of raw materials: 24 parts of silica sand particles with a particle size of 2.18 - 1.5 mm; 22 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 25 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 25 parts of silica sand fine powder with a particle size < 0.088 mm; 4 parts of waste brick particles with a particle size of 2.18 mm; 2 parts of silica powder; 2.5 parts of calcium hydroxide powder; 1.5 parts of fluorite powder; 1.3 parts of pyrophyllite; One or more of yellow dextrin, white dextrin or water are added as binders, and the total addition amount is 0.8 part.

[0021] Example 3: It includes the following parts by weight of raw materials: 28 parts of silica sand particles with a particle size of 2.18 - 1.5 mm; 18 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 28 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 23 parts of silica sand fine powder with a particle size < 0.088 mm; 3 parts of waste brick particles with a particle size of 2.18 mm; 3 parts of silica powder; 2 parts of calcium hydroxide powder; 1.3 parts of fluorite powder; 1.7 parts of pyrophyllite; One or more of yellow dextrin, white dextrin or water are added as binders, and the total addition amount is 0.8 part.

[0022] Comparative example: It includes the following parts by weight of raw materials: 27 parts of silica sand particles with a particle size of 2.18 - 1.5 mm; 18 parts of silica sand particles with a particle size of 1.5 - 0.5 mm; 27 parts of silica sand particles with a particle size of 0.5 - 0.1 mm; 23 parts of silica sand fine powder with a particle size < 0.088 mm; 5 parts of waste brick particles with a particle size of 2.18 mm; 3 parts of silica powder; 2 parts of calcium hydroxide powder; 5 parts of iron scale; One or two of bentonite or clay are added as mineralizing agents, and the total addition amount is 4 parts.

[0023] In actual preparation, the silica bricks prepared according to the above examples were tested for the following test indexes, and the specific data are shown in Table 1:

[0024] According to the test indexes shown in the above table, it can be clearly obtained that in the above examples, the thermal conductivity of the product obtained in Example 1 can reach 2.58 W / m·K after testing, the thermal conductivity of the product obtained in Example 2 can reach 2.53 W / m·K after testing, and the thermal conductivity of the product obtained in Example 3 can reach 2.55 W / m·K after testing. All these three examples have extremely high thermal conductivity coefficients. Compared with the comparative example, the high-temperature performance of the product is significantly improved, and its fired compressive strength, permanent linear change on heating and load softening temperature have all been effectively and reliably improved, and then it can better meet the refractory performance requirements of the carbon furnace for silica bricks.

[0025] More specifically, in the present application, in the formulation design, the mineralizing agent iron scale commonly used in traditional coke oven silica bricks and carbon furnace silica bricks is removed. After roasting, compared with the iron content of 0.6% - 1.0% in current market coke oven silica bricks and carbon furnace silica bricks, the iron content of the erosion-resistant carbon furnace silica bricks of the present application is only about 0.3%, which is the iron impurity content contained in natural ore. The lower iron content is beneficial to improving the erosion resistance of carbon furnace silica bricks. Thermodynamically, Fe 2 O 3 will react with C at high temperature: 2Fe 2 O 3 + 3C = 4Fe + 3CO 2 ↑, and the generated Fe reacts with S in petroleum coke to generate Fe 2S 3 At the same time, α-Fe in iron oxide 2 0 3 ·H 2 O can react with H in the carbonaceous furnace flue at room temperature 2 S, and Fe 2 O 3 ·H 2 O + 3H 2 S → Fe 2 S 3 ·H 2 O + 3H 2 O. A lower iron content is beneficial to improving the erosion resistance of silica bricks in carbonaceous furnaces.

[0026] Moreover, in the formulation design, pyrophyllite is used to replace the traditional mineralizer bentonite or clay. By utilizing the high lubricity and low potassium and sodium chemical properties of pyrophyllite, during the process of mechanically pressing semi-finished silica bricks, the frictional resistance with the mold is reduced, which is beneficial to improving the density of the semi-finished billet. At the same time, it ensures that micro-pores can be formed after the billet is fired, enhancing the high-temperature performance and erosion resistance of the product, thereby contributing to improving the service life of the carbonaceous furnace.

[0027] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A corrosion-resistant carbon furnace silicon brick, characterized in that: Including the following raw materials by weight composition: Among them, 20 to 30 parts of silica sand particles with a particle size of 2.18 to 1.5 mm; 15-25 parts of silica sand particles with a particle size of 1.5-0.5 mm; 20-30 parts of silica sand particles with a particle size of 0.5-0.1 mm; 3 to 15 parts of waste brick particles with a particle size of 2.18 mm; 20-30 parts of silica sand fine powder with particle size less than 0.088mm; 1-5 parts of silicon powder; Calcium hydroxide powder 2-3 parts; 1-2 parts of fluorite powder; 1-3 parts of pyrophyllite; 0.8 to 1.5 parts of binder.

2. The corrosion-resistant carbon furnace silicon brick according to claim 1, characterized in that: The chemical formula of pyrophyllite is Al2[Si4O 10 ](OH)2, in which, by weight: the theoretical content of Al2O3 is 28.3%, SiO2 is 66.7%, and H2O is 5.0%.

3. The corrosion-resistant carbon furnace silicon brick according to claim 1, characterized in that: The binder is a mixture of one or more of yellow dextrin, white dextrin and water.

4. A method for preparing a corrosion-resistant carbon furnace silicon brick according to any one of claims 1 to 3, characterized in that: The following steps are involved: S110, dry mixing: according to the raw material ratio, silica sand particles with a particle size of 2.18-1.5 mm, silica sand particles with a particle size of 1.5-0.5 mm, silica sand particles with a particle size of 0.5-0.1 mm, waste brick particles with a particle size of 2.18 mm, silica sand fine powder with a particle size of less than 0.088 mm, silicon powder, calcium hydroxide powder, fluorite powder, pyrophyllite and a binder are filled into a high-speed mixer and dry mixed for 1-3 minutes; S120, wet mixing: the dry mixed materials are put into the roller mill equipment, 4.5-6.5% water is added according to the amount of materials, and mixed for 10-20 minutes to form mud; S130, blank making: pressing the clay into a blank, sending it into a dryer for drying, and forming a brick blank; S140, firing: Place the dried bricks in a tunnel kiln for firing, and keep the temperature at 1380℃~1440℃ for 20~30h. After firing, cool naturally to room temperature with the kiln to obtain the product.

5. The method for preparing a corrosion-resistant carbon furnace silicon brick according to claim 4, characterized in that: In step S130, the temperature range of the dryer is 60-110°C, and the drying time range is 24-48 hours.

6. The method for preparing a corrosion-resistant carbon furnace silicon brick according to claim 4, characterized in that: In step S140, the total sintering time of the silicon bricks is 189 hours, and the insulation time in the high temperature zone is 32 hours.

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