Unburned casted corundum spinel slide plate brick and its preparation method

Abstract

The present application relates to a kind of slide plate unburned pouring corundum spinel quality slide plate brick and its preparation method, wherein unburned pouring corundum spinel quality slide plate brick, including the following weight percentage of components: sintered corundum 50%~80%, magnesium aluminate spinel 5%~25%, fused corundum 8%~11%, fused spinel 3%~5%, active alumina powder 5%~10%, pure calcium aluminate cement 5%~10%, medium-temperature sintering agent 1%~3%, polycarboxylic acid water reducing agent 1%~3%, explosion-proof fiber 0.05%~0.15%, in addition, preparation method, by weighing, mixing and forming step preparation the finished product.The present application is mainly to adjust product component, shorten and adjust product preparation cycle at the same time, reduce preparation process, green production without firing, without oil immersion, meet the modern production demand of low carbon environmental protection.

Description

Technical Field

[0001] This invention relates to the field of sliding block technology, specifically to a non-fired cast corundum spinel sliding block and its preparation method. Background Technology

[0002] With the development of steel smelting technology and the continuous increase in market demand for steel, the types of steel are constantly increasing, such as low carbon steel, ultra-low carbon steel, pure steel, and high oxygen steel. The carbon content in some steels has even dropped to 10 ppm. Traditional aluminum-carbon or aluminum-zirconium-carbon refractory squeegees can no longer meet the casting requirements of all steel types. Therefore, it is necessary to develop more carbon-free refractory squeegee materials to meet the casting needs.

[0003] Many steel mills require the use of carbon-free refractory materials for the entire ladle and also have specific requirements for slide plates. However, many carbon-free slide plates are either ineffective or too expensive (such as zirconium-based ones) when used in continuous casting, and their production process is complex, requiring firing in addition to normal forming processes such as clamping and casing, which consumes a lot of energy. Therefore, the development of non-fired carbon-free slide plates is needed to reduce carbon pollution of molten steel, reduce emissions during production, and improve their performance.

[0004] Traditional sliding gate bricks use phenolic resin as a binder and are fired to increase strength. For example, in the prior art, the invention patent with application number 201410091958.6, entitled "A New Type of Automatic Slag-Blocking Sliding Gate Brick for Converter and Its Preparation Method", discloses that the sliding gate bricks contain resin as a binder. In its manufacturing process, firing, oil immersion, and dry distillation are required. As is well known, the resin decomposes when heated during the production process, producing VOCs emissions and polluting the environment. In addition, firing requires a lot of energy and emits pollutants such as sulfur dioxide and nitrogen oxides. The oil immersion and dry distillation processes also require energy. At the same time, the fumes and waste asphalt produced by asphalt pollute the environment and are also detrimental to human health. The steel hoop also requires heating, which consumes energy, and drying is required after the steel shell is installed, which also consumes energy.

[0005] Therefore, it is necessary to research and develop a new type of non-fired cast corundum spinel slide block, adjust the composition of the slide block, reduce the preparation process accordingly, and shorten the production cycle. The main purpose is to significantly reduce the degree of environmental pollution caused by the production process, which is in line with the green and environmentally friendly development trend of modern production. Summary of the Invention

[0006] To address the aforementioned problems, the main objective of this invention is to provide a non-fired cast corundum spinel slide block and its preparation method. This method primarily involves adjusting the product composition, shortening and adjusting the product preparation cycle, reducing preparation steps, and achieving green production without firing or oil immersion, thus meeting the needs of low-carbon and environmentally friendly modern production.

[0007] To achieve the above objectives, the non-fired castable corundum spinel sliding plate brick of the present invention comprises the following components by weight percentage: 50%–80% sintered corundum, 5%–25% magnesium aluminum spinel, 8%–11% fused corundum, 3%–5% fused spinel, 5%–10% activated alumina micro powder, 5%–10% pure calcium aluminate cement, 1%–3% medium-temperature sintering agent, 1%–3% polycarboxylate superplasticizer, and 0.05%–0.15% explosion-proof fiber. The sum of the weights of all components in the above formula is 100%, with an additional 4%–6% water by weight.

[0008] Furthermore, the particle size distribution of each component is as follows: the particle diameter of sintered corundum is (5-3, 3-1, 1-0) mm; magnesium aluminum spinel includes particles and fine powder, wherein the particle diameter of magnesium aluminum spinel is 1-0 mm, the fine powder of magnesium aluminum spinel is 20 μm, the particle diameter of fused corundum is 1-0 mm, the active alumina micro powder is 2 μm, the medium-temperature sintering agent is 325 mesh, and the pure calcium aluminate cement is 325 mesh.

[0009] Furthermore, the sintered corundum particle size distribution by weight percentage is as follows: 5–3 mm, 15%–22%; 3–1 mm, 20%–30%; 1–0 mm, 16%–19%; and the magnesium aluminum spinel particle and fine powder size distribution by weight percentage is as follows: 1–0 mm, 5%–20%; 20 μm, 3%–10%.

[0010] Furthermore, the composition and content of each component are as follows: Sintered corundum: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.5%, Na2O content ≤ 0.2%; Fused corundum: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.5%, Na2O content ≤ 0.1%; Magnesium aluminum spinel: Al2O3 content ≥ 75%, MgO content ≥ 20%; Activated alumina micro powder: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.2%; Pure calcium aluminate cement: Al2O3 content ≥ 68%, CaO content ≥ 28%; Medium-temperature sintering agent: MgO content ≥ 20%, Al2O3 content ≥ 50%; Water is natural water with pH = 7.

[0011] In addition, the present invention also proposes a method for preparing non-fired cast corundum spinel sliding plate bricks, comprising the following steps:

[0012] Step S1: Weighing

[0013] According to the weight percentage of each component, sintered corundum, fused corundum, fused spinel, magnesium aluminum spinel, activated alumina micro powder, pure calcium aluminate cement, medium-temperature sintering agent, polycarboxylate superplasticizer, explosion-proof fiber and water are weighed separately.

[0014] Step S2: Mixing

[0015] Weigh out sintered corundum, fused corundum, magnesium aluminum spinel, pure calcium aluminate cement, activated alumina micro powder, explosion-proof fiber, polycarboxylate superplasticizer, medium-temperature sintering agent and water and add them to a mixer to mix and stir to obtain a mud mixture.

[0016] Step S3: Molding

[0017] The clay mixture from the above steps is poured into a mold, cured, and then placed in a drying kiln to dry for 46–60 hours at a temperature of 100–220°C. After drying, the product is cooled to room temperature, and finally, it is ground and coated with lubricant.

[0018] Furthermore, in step S3, the mud mixture is injected into the steel shell, first vibrated for 1-2 minutes, cured for 5-8 hours, demolded, and then cured for another 8-12 hours. During the drying process in step S3, the product after demolding and curing is gradually and evenly heated to 100°C within 12 hours; then kept at 100°C for 8 hours; next, the temperature is gradually and evenly increased from 100°C to 220°C within 20 hours; and kept at 220°C for 6-15 hours; finally, it is cooled to room temperature.

[0019] Furthermore, step S2 mixing also includes the following sub-steps:

[0020] Step S21: First, add the weighed sintered corundum, fused corundum, magnesium aluminum spinel, pure calcium aluminate cement, activated alumina micro powder, explosion-proof fiber and water to the mixer for the first mixing.

[0021] Step S22: Then add the polycarboxylate superplasticizer to the mixer for a second mixing;

[0022] Step S23: Then add the medium-temperature sintering agent to the above mixer for a third mixing to obtain a mud mixture.

[0023] Furthermore, the first mixing time in step S21 is 3-5 minutes; the second mixing time in step S22 is 2-3 minutes; and the third mixing time in step S23 is 2-3 minutes.

[0024] Furthermore, step S2 mixing also includes the following sub-steps:

[0025] Step S24: First, weigh each component according to step S1, then divide the water into two equal parts. Add the weighed sintered corundum, fused corundum, fused spinel, magnesium aluminum spinel, pure calcium aluminate cement and explosion-proof fiber, and one of the two equal parts of water to the mixer for mixing to obtain a premix.

[0026] Step S25: Add the medium-temperature sintering agent and polycarboxylate superplasticizer to the reactor, add the remaining water, mix thoroughly, and prepare a suspension;

[0027] Step S26: Add the suspension to the mixer and mix it with the mixture to obtain a mud mixture.

[0028] Furthermore, the mixing time in step S24 is 3-5 minutes; the mixing time in step S26 is 2-3 minutes.

[0029] The technical effects that can be achieved by the present invention through the above technical solution include:

[0030] The product components of this invention do not contain phenolic resin or the like as binders, so that no related gaseous pollutants are generated during its preparation.

[0031] The production process of the sliding plate brick of this invention is simple, eliminating the steps of firing, oil immersion and roasting, thus preventing the generation of pollutants such as sulfur dioxide and nitrogen oxides during the production process. At the same time, the production steps are simplified, eliminating the need for steel hoops, and the brick is directly cast into a steel shell without the need for a steel shell after molding. This reduces the drying steps, saves energy, and improves the product qualification rate.

[0032] The finished sliding plate brick obtained by the preparation method of the present invention has high fire resistance and compressive strength, good erosion resistance and scour resistance. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Example 1

[0035] This embodiment describes a method for preparing non-fired castable corundum spinel sliding block bricks. The raw materials for preparing the non-fired castable corundum spinel sliding block bricks, by weight percentage, include: 50%–80% sintered corundum, 5%–25% magnesium aluminum spinel, 8%–11% fused corundum, 3%–5% fused spinel, 5%–10% activated alumina micropowder, 5%–10% pure calcium aluminate cement, 1%–3% medium-temperature sintering agent, 1%–3% polycarboxylate superplasticizer, and 0.05%–0.15% explosion-proof fiber. The sum of the weights of all components in the above formula is 100%, with additional weight percentages not included. The mixture contains 4%–6% water, wherein the particle size distribution of sintered corundum by weight percentage is: 5–3 mm, 15%–22%, 3–1 mm, 20%–30%, 1–0 mm, 16%–19%, and magnesium aluminum spinel includes particles and fine powder, wherein the magnesium aluminum spinel particles have a diameter of 1–0 mm and a weight percentage of 5%–20%, the magnesium aluminum spinel fine powder has a diameter of 20 μm and a weight percentage of 3%–10%, the fused alumina particles have a diameter of 1–0 mm, the activated alumina micro powder has a diameter of 2 μm, the medium-temperature sintering agent has a mesh size of 325, and the pure calcium aluminate cement has a mesh size of 325.

[0036] In addition, the composition and content of each component are as follows: sintered corundum: Al2O3 content ≥98.5%, Fe2O3 content ≤0.5%, Na2O content ≤0.2%; fused alumina: Al2O3 content ≥98.5%, Fe2O3 content ≤0.5%, Na2O content ≤0.1%; magnesium aluminum spinel: Al2O3 content ≥75%, MgO content ≥20%; activated alumina micro powder: Al2O3 content ≥98.5%, Fe2O3 content ≤0.2%; pure calcium aluminate cement: Al2O3 content ≥68%, CaO content ≥28%; medium-temperature sintering agent: MgO content ≥20%, Al2O3 content ≥50%; in addition, the water is natural water with a pH value of 7.

[0037] Specifically, the preparation method of unfired cast corundum spinel sliding plate bricks is as follows:

[0038] Step S1: Weighing

[0039] According to the above requirements, weigh out the following components by weight: 60% sintered corundum, 10% magnesium aluminum spinel, 9% fused corundum, 4% fused spinel, 6.5% activated alumina micro powder, 6.4% pure calcium aluminate cement, 2% medium-temperature sintering agent, 2% polycarboxylate superplasticizer, and 0.1% explosion-proof fiber, plus an additional 6% water by weight.

[0040] Step S2: Mixing

[0041] Weigh out sintered corundum, fused corundum, magnesium aluminum spinel, pure calcium aluminate cement, activated alumina micro powder, explosion-proof fiber, polycarboxylate superplasticizer, medium-temperature sintering agent and water and add them to a mixer for 12 minutes to obtain a mud mixture.

[0042] Step S3: Molding

[0043] The clay mixture from the above steps is poured into a steel shell. First, it is vibrated for 2 minutes and cured for 7 hours before demolding. After demolding, it is cured for another 10 hours before proceeding to the drying step. During the drying process, the product after demolding and curing is gradually and evenly heated to 100°C over 12 hours, and then kept at 100°C for 8 hours. Next, the temperature is gradually and evenly increased from 100°C to 220°C over 20 hours and kept at 220°C for 6 to 15 hours. Finally, it is cooled to room temperature.

[0044] Comparative Examples 1-5

[0045] Comparative Examples 1-5 are methods for preparing unfired cast corundum spinel sliding block bricks. The preparation methods in these comparative examples are basically the same as those in Example 1, except that the types or contents of certain components are different in each comparative example, as detailed in the table below:

[0046] Table 1. Comparison of component parameters between Example 1 and Comparative Examples 1-5

[0047]

[0048] The other contents of Comparative Examples 1 to 5 are exactly the same as those of Example 1, and will not be repeated here.

[0049] According to the "Sampling Inspection Rules for Acceptance of Shaped Refractory Products" (GB / T 10325-2012), the sliding block P1 obtained in Example 1 and the sliding blocks D1 to D5 obtained in each comparative example were tested, and the test results are as follows:

[0050] Table 2 Comparison of Product Test Data between Example 1 and Comparative Examples 1-5

[0051]

[0052] Analysis of the test results of Example 1 and Comparative Examples 1-5 shows that when the raw materials fused alumina and fused spinel were removed in Comparative Example 1, the refractoriness of the final product did not meet the national standard value within ±0.5%, and the compressive strength and erosion resistance were significantly reduced. This indicates that the addition of fused alumina and fused spinel improved the hardness and erosion resistance of the finished sliding plate brick. In Comparative Example 2, the removal of the raw material activated alumina powder resulted in poor impermeability of the final product. Even with a higher activated alumina powder content in Comparative Example 1, the impermeability of the final product was not enhanced. Therefore, the activated alumina powder content in Example 1 is considered optimal. In Comparative Example 3... Removing the explosion-proof fiber from the raw material revealed that the product cracked under the same specific testing conditions. In Comparative Example 4, removing the polycarboxylate superplasticizer from the raw material affected the wear resistance, compressive strength, and erosion resistance of the final product. This is understandable, as the polycarboxylate superplasticizer affects the hydration process and may alter the formation rate and morphology of hydration products, thus impacting the overall performance of the final product. In Comparative Example 5, removing the medium-temperature sintering agent from the raw material is problematic. The medium-temperature sintering agent allows the product to form a dense morphology at relatively low temperatures, enabling the raw material to form a liquid phase at lower temperatures, thereby promoting the sintering process of the sliding plate bricks. The absence of this component also resulted in certain deviations in the performance of the final product.

[0053] Example 2

[0054] Example 2 is a method for preparing unfired cast corundum spinel sliding block. The raw material dosage is exactly the same as in Example 1, and the preparation steps are basically the same as in Example 1. The difference is that in this example, step S2 mixing includes the following sub-steps:

[0055] Step S21: First, add the weighed sintered corundum, fused corundum, magnesium aluminum spinel, pure calcium aluminate cement, activated alumina micro powder, explosion-proof fiber and water to the mixer for the first mixing and stirring for 5 minutes.

[0056] Step S22: Then add the polycarboxylate superplasticizer to the mixer for a second mixing and stirring for 3 minutes;

[0057] Step S23: Then add the medium-temperature sintering agent to the above mixer for a third mixing and stirring for 3 minutes to obtain a mud mixture, and then proceed to the next step of preparation.

[0058] Example 3

[0059] Example 3 is a method for preparing unfired cast corundum spinel sliding block. The raw material dosage is exactly the same as in Example 1, and the preparation steps are basically the same as in Example 1. The difference is that in this example, step S2 mixing includes the following sub-steps:

[0060] Step S24: First, weigh each component according to step S1, then divide the water into two equal parts. Add the weighed sintered corundum, fused corundum, fused spinel, magnesium aluminum spinel, pure calcium aluminate cement and explosion-proof fiber, and one of the two equal parts of water to the mixer for mixing. The mixing time is 5 minutes to obtain a premix.

[0061] Step S25: Add the medium-temperature sintering agent and polycarboxylate superplasticizer to the reactor, add the remaining water, mix thoroughly, and prepare a suspension;

[0062] Step S26: Add the suspension to the mixer and mix it with the mixture for 3 minutes to obtain a mud mixture, and then proceed to the next step of preparation.

[0063] Table 3 Comparison of Product Test Data for Each Embodiment

[0064]

[0065] Analysis of the test results from Examples 1, 2, and 3 shows that while the method of directly mixing all raw materials in Example 1 to prepare sliding plate bricks has achieved the high fire resistance, compressive strength, and erosion resistance of sliding plate bricks compared to existing technologies, adjustments to step S2 are necessary. In Example 2, the mixing is performed in stages. In step S21, some raw materials are first thoroughly mixed, and then the water-reducing agent and sintering agent are added separately and mixed evenly. Although this simply adds a mixing step by adding the two components separately, the polycarboxylate superplasticizer and the medium-temperature sintering agent have a significant effect. The polycarboxylate superplasticizer molecules adsorb onto the surface of cement particles, giving the cement particles a negative charge, thus generating electrostatic repulsion. This promotes the dispersion of cement particles, destroys the flocculation structure, and releases the water that was originally trapped within the flocculation structure, allowing it to participate in the flow of other mixtures. The COO2 in the polycarboxylate superplasticizer... - With Ca2 +The formation of ions into complexes reduces the concentration of calcium ions in the mixture slurry, delays the crystallization of Ca(OH)2, and reduces the formation of CSH gel, thereby slowing down the hydration process of the substances. In addition, the phased addition and thorough mixing of the medium-temperature binder and polycarboxylate superplasticizer can improve the utilization rate of these two substances and improve the final compressive strength and erosion resistance of the product. Although it is a simple adjustment of the order of component addition and the number of stirrings, the technical effect achieved is significantly enhanced. Furthermore, in Example 3, water is added in two stages, with one stage mixed with most of the raw materials, and the remaining water mixed with the medium-temperature sintering agent and polycarboxylate superplasticizer to form a suspension. The principle is still the same as that of Example 2. The medium-temperature sintering agent and polycarboxylate superplasticizer prepared as a suspension react more fully with the other raw material mixture, which improves the utilization rate of these two substances in another way and enhances the performance of various indicators of the final product.

[0066] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A non-fired cast corundum spinel sliding plate brick, characterized in that, The sliding brick comprises the following components by weight percentage: 50%–80% sintered corundum, 5%–25% magnesium aluminum spinel, 8%–11% fused corundum, 3%–5% fused spinel, 5%–10% activated alumina micro powder, 5%–10% pure calcium aluminate cement, 1%–3% medium-temperature sintering agent, 1%–3% polycarboxylate superplasticizer, and 0.05%–0.15% explosion-proof fiber. The sum of the weights of all components in the above formula is 100%, plus 4%–6% water by weight. The particle size distribution of each component is as follows: sintered corundum has particle diameters of 5-3 mm, 3-1 mm, and 1-0 mm; magnesium aluminum spinel includes particles and fine powder, wherein the magnesium aluminum spinel particles have a diameter of 1-0 mm, the magnesium aluminum spinel fine powder has a diameter of 20 μm, the fused corundum particles have a diameter of 1-0 mm, the activated alumina micro powder has a diameter of 2 μm, the medium-temperature sintering agent has a diameter of 325 mesh, and the pure calcium aluminate cement has a diameter of 325 mesh. A method for preparing a non-fired cast corundum spinel sliding plate brick includes the following steps: Step S1: Weighing According to the weight percentage of each component, sintered corundum, fused corundum, fused spinel, magnesium aluminum spinel, activated alumina micro powder, pure calcium aluminate cement, medium-temperature sintering agent, polycarboxylate superplasticizer, explosion-proof fiber and water are weighed separately. Step S2: Mixing Weigh out sintered corundum, fused corundum, fused spinel, magnesium aluminum spinel, pure calcium aluminate cement, activated alumina micro powder, explosion-proof fiber, polycarboxylate superplasticizer, medium-temperature sintering agent and water and add them to a mixer for mixing to obtain a mud mixture. Step S3: Molding The clay mixture from the above steps is poured into a mold, cured, and then placed in a drying kiln to dry for 46-60 hours at a temperature of 100-220°C. After drying, the product is cooled to room temperature and then polished and coated with lubricant. In step S3, the clay mixture is injected into a steel shell, vibrated for 1-2 minutes, cured for 5-8 hours, demolded, and then cured for another 8-12 hours. During the drying process in step S3, the product after demolding and curing is gradually and uniformly heated to 100°C over 12 hours; then kept at 100°C for 8 hours; next, the temperature is gradually and uniformly increased from 100°C to 220°C over 20 hours; and kept at 220°C for 6-15 hours; finally, it is cooled to room temperature. The composition of the medium-temperature sintering agent is: MgO content ≥ 20%, Al2O3 content ≥ 50%.

2. The unfired cast corundum spinel sliding plate brick according to claim 1, characterized in that, The sintered corundum particle size distribution, by weight percentage, is as follows: 5–3 mm, 15%–22%; 3~1mm, 20%~30%; 1~0mm, 16%~19%; The magnesium aluminum spinel particles and fine powder gradation are as follows by weight percentage: 1~0mm, 5%~20%; 20μm, 3%~10%.

3. The unfired cast corundum spinel sliding plate brick according to claim 1, characterized in that, The content of each component is as follows: The sintered corundum has the following composition: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.5%, Na2O content ≤ 0.2%; the fused alumina has the following composition: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.5%, Na2O content ≤ 0.1%; the magnesium aluminum spinel has the following composition: Al2O3 content ≥ 75%, MgO content ≥ 20%; the activated alumina micropowder has the following composition: Al2O3 content ≥ 98.5%, Fe2O3 content ≤ 0.2%; the pure calcium aluminate cement has the following composition: Al2O3 content ≥ 68%, CaO content ≥ 28%. The water is natural water with a pH of 7.

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