An erosion-resistant carbon furnace silica brick and its preparation method

Abstract

The present invention discloses an erosion-resistant carbon furnace silica brick and a preparation method thereof, which comprise 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 fume; 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. The beneficial effects are as follows: 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.

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. The silica brick is an important raw material for building the carbon furnace. 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 the carbon furnace. In the actual production process, the silica brick is prone to erosion and damage, thus affecting its service life. The main factors affecting the service life of the carbon furnace are as follows: ① The quality of the silica brick. For example, if the residual quartz content in the brick 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 the silica brick may be eroded under the action of sulfur, and the higher the sulfur content, the more obvious the erosion effect on the silica brick.

[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 the silica brick of the carbon furnace: ① Select high-quality silica raw materials. Specifically, because the purity, density, and quartz crystal content of different quartzites are different, and the 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 mineralizer 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] However, in the specific method of ②, although using iron scale and clay as mineralizers can enhance the strength of the silica brick, due to the general lubricating ability of iron scale and clay, the silica brick will have a large frictional resistance with 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 described in detail below.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] An erosion-resistant carbon furnace silica brick provided by the present invention comprises the following raw materials in parts by mass:

[0008] Among them, 20 - 30 parts of silica sand particles with a particle size of 2.18 - 1.5 mm;

[0009] 15 - 25 parts of silica sand particles with a particle size of 1.5 - 0.5 mm;

[0010] 20 - 30 parts of silica sand particles with a particle size of 0.5 - 0.1 mm;

[0011] 3 - 15 parts of waste brick particles with a particle size of 2.18 mm;

[0012] 20 - 30 parts of silica sand fine powder with a particle size < 0.088 mm;

[0013] 1 - 5 parts of silica fume;

[0014] 2 - 3 parts of calcium hydroxide powder;

[0015] 1 - 2 parts of fluorite powder;

[0016] 1 - 3 parts of pyrophyllite;

[0017] 0.8 - 1.5 parts of binder.

[0018] Preferably, the chemical formula of the 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%.

[0019] Preferably, the binder is one or a mixture of yellow dextrin, white dextrin and water.

[0020] The preparation method of the above anti - erosion carbon furnace silica brick includes the following steps:

[0021] 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 fume, 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;

[0022] S120, wet mixing: Fill the dry - mixed material into a roller mill equipment, add 4.5 - 6.5% water according to the amount of the material, and mix for 10 - 20 min to form a mud;

[0023] S130, blank making: Press the mud into a blank, and send it into a dryer for drying to form a brick blank;

[0024] 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, and then cool it naturally in the furnace to room temperature to obtain the product.

[0025] Preferably, in step S130, the temperature range of the dryer is 60-110°C, and the drying duration range is 24-48H.

[0026] Preferably, in step S140, the total firing time of the silica brick is 189 hours, and the heat preservation time in the high-temperature zone is 32 hours.

[0027] 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, Fe2O3 in the silica brick will react with C at high temperature: 2Fe2O3 + 3C = 4Fe + 3CO2↑. The generated Fe reacts with S in the petroleum coke to form Fe2S3. At the same time, α-Fe203·H2O in the iron oxide can react with H2S in the carbon furnace flue at room temperature, Fe2O3·H2O + 3H2S → Fe2S3·H2O + 3H2O. The lower iron content is beneficial to improving the erosion resistance of the carbon furnace silica brick;

[0028] 2. At the same time, in the formulation design, pyrophyllite is used to replace the traditional mineralizer bentonite or clay. Utilizing the high lubrication performance and low potassium and sodium chemical properties of pyrophyllite, during the process of mechanically pressing the semi-finished silica brick, the frictional resistance with the template is reduced, which is beneficial to improving the density of the semi-finished product blank. At the same time, it ensures that micropores can be formed after the blank is fired, improving the high-temperature performance and erosion resistance of the product, and thus helping to improve the service life of the carbon furnace. Specific Embodiments

[0029] 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 embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0030] An erosion-resistant carbon furnace silica brick provided by the present invention comprises the following raw materials in parts by mass:

[0031] Among them, 20-30 parts of silica sand particles with a particle size of 2.18-1.5 mm;

[0032] 15-25 parts of silica sand particles with a particle size of 1.5-0.5 mm;

[0033] 20-30 parts of silica sand particles with a particle size of 0.5-0.1 mm;

[0034] 3 - 15 parts of waste brick particles with a particle size of 2.18 mm;

[0035] 20 - 30 parts of silica sand fine powder with a particle size < 0.088 mm;

[0036] 1 - 5 parts of silica powder;

[0037] 2 - 3 parts of calcium hydroxide powder;

[0038] 1 - 2 parts of fluorite powder;

[0039] 1 - 3 parts of pyrophyllite;

[0040] 0.8 - 1.5 parts of binder.

[0041] For the above - mentioned scheme, the following more specific optimizations are carried out. Specifically, the chemical formula of the 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%, so as to accurately add pyrophyllite with a suitable chemical specification according to the above parameters. Optionally, the binder is one or a mixture 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.

[0042] Specifically for the preparation method, a preparation method of erosion - resistant carbon furnace silica brick includes the following steps:

[0043] 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;

[0044] 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;

[0045] S130, blank making: Press the mud into a blank, and send it into a dryer for drying to form a brick blank;

[0046] 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 in the furnace to room temperature to obtain the product.

[0047] 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 mineralizing agents, pyrophyllite and a catalyst are introduced, and sintering is carried out at high temperature. Utilizing the high lubricity performance and low potassium and sodium chemical properties of pyrophyllite, during the forming process, the frictional resistance with the template is reduced, which is beneficial to improving the density of the semi-finished blank. After firing, micro-pores are formed to enhance the high-temperature performance of the product, thereby increasing the service life of the carbon furnace.

[0048] 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. With such settings, first, it is convenient for the bucket lid to ensure the technical indicators for reference when making silica bricks by clarifying the working parameters of the dryer. 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 such settings is to ensure that the firing time of the silica brick has a clear and referenceable duration, facilitating the batch firing of silica bricks.

[0049] With the help of this solution and according to the following embodiments for implementation verification, the specific embodiments are as follows:

[0050] 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.

[0051] 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 5 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.

[0052] Example 3: It includes raw materials in the following parts by weight: 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 fume; 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.

[0053] Comparative Example: It includes raw materials in the following parts by weight: 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 fume; 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.

[0054] 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:

[0055]

[0056] It can be clearly obtained from the test indexes shown in the above table 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 cold crushing strength, permanent linear change on heating and load softening temperature are effectively and reliably improved, and then it can better meet the refractory performance requirements of the carbon furnace for silica bricks.

[0057] More specifically, in the present application, in the formulation design, the mineralizer 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 brick of the present application 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, Fe2O3 in the silica brick will react with C at high temperature: 2Fe2O3 + 3C = 4Fe + 3CO2↑. The generated Fe reacts with S in the petroleum coke to form Fe2S3. At the same time, α-Fe203·H2O in the iron oxide can react with H2S in the carbon furnace flue at room temperature, Fe2O3·H2O + 3H2S → Fe2S3·H2O + 3H2O. The lower iron content is beneficial to improving the erosion resistance of the carbon furnace silica brick.

[0058] Moreover, in the formulation design, pyrophyllite is used to replace the traditional mineralizer bentonite or clay. Utilizing the high lubrication performance and low potassium and sodium chemical properties of pyrophyllite, during the process of mechanically pressing the semi-finished silica brick, the frictional resistance with the template is reduced, which is beneficial to improving the density of the semi-finished blank. At the same time, it ensures that micro-pores can be formed after the blank is fired, enhancing the high-temperature performance and erosion resistance of the product, thus contributing to improving the service life of the carbon furnace.

[0059] The above 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 claimed rights.

Claims

1. An erosion-resistant carbon furnace silica brick, characterized in that: Comprising raw materials in the following parts by mass Composition: 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.

2. The anti-corrosion carbon furnace silica brick according to claim 1, wherein: The pyrophyllite has the chemical formula Al2[Si4O 10 (OH)2, wherein, by weight parts, the theoretical content of Al2O3 is 28.3%, SiO2 is 66.7%, and H2O is 5.0%.

3. The anti-corrosion carbon furnace silica brick according to claim 1, wherein: The binder is one or a mixture of yellow dextrin, white dextrin and water.

4. The preparation method of an erosion-resistant carbon furnace silica brick according to any one of claims 1-3, characterized in that: Including the following steps: S110, Dry mixing: According to the raw material ratio, 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, and dry mix for 1 - 3 min; S120, Wet mixing: Fill the dry - mixed material into a roller compactor, add 4.5 - 6.5% water according to the amount of the material, and mix for 10 - 20 min to form a mud; S130, Molding: 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 naturally cool it to room temperature with the furnace after firing to obtain the product.

5. The preparation method of an erosion-resistant carbon furnace silica brick according to claim 4, characterized in that: In step S130, the temperature range of the dryer is 60 - 110℃, and the drying duration range is 24 - 48 h.

6. The preparation method of an erosion-resistant carbon furnace silica brick according to claim 4, wherein: 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.

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