High-purity spinel dry vibration material production method for cast steel intermediate frequency furnace

Abstract

The invention relates to the field of spinel production, in particular to a production method of a high-purity spinel dry vibration material for a cast steel intermediate frequency furnace, and the production of the high-purity spinel dry vibration material is realized through the steps of raw material selection, raw material mixing, additive adding, presintering, synthetic reaction, material crushing, screening and the like. According to the high-purity spinel dry vibration material production method for the cast steel intermediate frequency furnace, high-purity magnesium oxide and aluminum oxide micro powder are selected, it is ensured that the raw materials are high in activity and free of impurities, a continuous mixer and a microwave-assisted heating technology are adopted, the hydrogen protective atmosphere is matched, sintering is accelerated, and generation of bad by-products is prevented; meanwhile, fine crushing and screening are performed, so that the particle size uniformity is ensured, the flowability is enhanced, the binding power and thermal shock resistance are improved, no harmful residue is ensured at high temperature, the product performance is remarkably improved, and the requirements of high-performance refractory materials are met.

Description

Technical Field

[0001] The invention relates to the field of spinel production, in particular to a method for producing high-purity spinel dry vibration material for a steel casting medium frequency furnace. Background Art

[0002] In the application of steel casting medium frequency furnace, the quality of refractory materials is directly related to the service life and production efficiency of the furnace lining. Although the traditional high-purity spinel dry vibration material production process can meet the use requirements to a certain extent, it still has many shortcomings in raw material selection, mixing uniformity, sintering technology and additive application.

[0003] First, the purity of the raw materials of magnesium oxide (MgO) and aluminum oxide (Al2O3) used in the traditional process usually does not exceed 99.5%, which inevitably leads to a certain amount of impurities in the final product, affecting the purity and reactivity of the material. In addition, the uniform distribution of the two components cannot be fully guaranteed during the mixing process, which makes the problem of local uneven composition occur from time to time, thus affecting the overall performance of the material. Secondly, in the synthesis reaction stage, the traditional method mostly uses electric heating for sintering. This heating method not only has high energy consumption, but also has uneven temperature distribution, which is easy to cause poor crystal growth and affect the microstructure and mechanical strength of the product. More importantly, the lack of effective atmosphere control measures makes magnesium oxide prone to premature reaction or generation of undesirable by-products at high temperatures, reducing the purity and stability of the material. Furthermore, the crushing and screening processes in the prior art are relatively extensive, and the particle size distribution of the final product cannot be accurately controlled, resulting in poor material fluidity and compaction characteristics, and it is difficult to adapt to the requirements of complex lining construction. At the same time, the grinding media commonly used in the ball milling process may introduce metal contamination, further weakening the purity of the material. Finally, regarding the application of additives, traditional practices often fail to find a suitable combination of binders and expanders, or even if suitable additives are found, the proportion of additives is not reasonable and the role of additives cannot be fully utilized. For example, some additives may leave harmful substances at high temperatures, which may pose a potential threat to the environment and human health.

[0004] Therefore, how to overcome the above-mentioned technical problems and defects becomes a key issue that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects described in the background technology, thereby realizing a method for producing high-purity spinel dry vibration material for cast steel medium frequency furnace. By selecting high-purity magnesium oxide and aluminum oxide powders, the raw materials are ensured to be highly active and free of impurities. A continuous mixer and microwave-assisted heating technology are used, combined with a hydrogen protective atmosphere, to accelerate sintering and prevent the formation of undesirable by-products. At the same time, fine crushing and screening are performed to ensure uniform particle size, enhance fluidity, improve adhesion and thermal shock resistance, and ensure no harmful residues at high temperatures, thereby significantly improving product performance and meeting the needs of high-performance refractory materials.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is: a method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace, comprising the following steps: Step 1: Select raw materials, such as magnesium oxide MgO with a purity greater than 99.6% and aluminum oxide powder Al2O3 with a purity greater than 99.6%, ensuring that both are highly active and free of impurities. Polyvinyl alcohol is used as a binder and wollastonite is used as an expansion agent.

[0007] Step 2: Mix the raw materials. Accurately weigh magnesium oxide and aluminum oxide according to a molar ratio of 1:2, and then put the two into a high-speed mixer and mix them evenly for 65 minutes.

[0008] Step 3: Add additives, add polyvinyl alcohol and wollastonite after the magnesium oxide and the aluminum oxide are fully mixed. The addition ratios of polyvinyl alcohol and wollastonite are between 0.8%-1.8% and 3.5%-7.8% of the total weight, respectively.

[0009] Step 4: Pre-sintering: The mixed powder is placed in a resistance furnace and kept at 1150°C for 6.5 hours to remove moisture and other volatile substances and promote initial reactions. It is then cooled naturally to room temperature.

[0010] Step 5: Synthesis reaction: put the pretreated mixture into a high-temperature electric furnace and perform a sintering reaction at 1550°C with a heating rate of 150°C per hour. After reaching the set temperature, keep the constant temperature for 11 hours.

[0011] Step 6: Material crushing: Use a jaw crusher to crush the block material after synthesis to a maximum particle size of no more than 10 mm, and use a ball mill to further refine the material until the average particle size reaches 0.08 mm-0.5 mm.

[0012] Step 7: Screening: The fine powder is graded through a vibrating screen to ensure that the particle size distribution meets the requirements and the particle size of the powder is controlled to be 230-280 mesh.

[0013] In the above-mentioned method for producing high-purity spinel dry vibration material for steel casting medium-frequency furnace, the magnesium oxide and aluminum oxide are mixed using a continuous mixer to ensure that the two components are completely fused.

[0014] In the above-mentioned method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace, the high-temperature electric furnace sintered the mixture by microwave assisted heating technology.

[0015] In the above-mentioned method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace, hydrogen is supplied to the interior of the high-temperature electric furnace when it is in use to prevent magnesium oxide from reacting prematurely or generating undesirable by-products.

[0016] In the above-mentioned method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace, the grinding medium in the ball mill is zirconia balls, and the ball-to-material ratio is 4:1.

[0017] Compared with the prior art, the method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention has at least the following beneficial effects: The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention ensures that the two key raw materials not only have extremely high purity but also maintain high reactivity by strictly selecting magnesium oxide (MgO) and aluminum oxide powder (Al2O3) with a purity greater than 99.6% and taking a series of chemical analysis and physical property evaluation measures, which helps to improve the performance of the final product and reduce the influence of impurities on the material structure and function.

[0018] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention adopts a continuous mixer for mixing treatment for up to 65 minutes, ensuring that the two components of magnesium oxide and aluminum oxide can be fully and evenly fused together. Compared with traditional methods, this method can more effectively avoid the problem of local uneven composition, thereby improving the consistency and stability of the material.

[0019] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention uses microwave assisted heating technology instead of traditional electric heating method in the synthesis reaction stage. This heating method not only accelerates the sintering speed and reduces energy consumption, but more importantly, it can provide a more uniform temperature distribution, promote the quality of crystal growth, and thus improve the comprehensive performance of the product.

[0020] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention supplies hydrogen as protective gas in the high-temperature electric furnace, which effectively prevents magnesium oxide from reacting prematurely or generating undesirable by-products, which is crucial for maintaining the purity of the material, and also ensures the integrity of the spinel phase formation.

[0021] The method for producing high-purity spinel dry vibration material for cast steel medium frequency furnace of the present invention utilizes a jaw crusher to crush the block material to a maximum particle size of no more than 10 mm, and further refines it to an average particle size between 0.08 mm and 0.5 mm through a ball mill, and then undergoes grading treatment through a vibrating screen to ensure that the particle size distribution of the final product meets strict industrial standards. The use of 230-280 mesh fine powder allows the material to have better fluidity and compaction properties, and is suitable for the construction of furnace linings of complex shapes.

[0022] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention selects zirconia balls as grinding media during ball milling, and the ball-to-material ratio is set to 4:1. Such a combination not only improves the grinding efficiency, but also reduces the risk of metal contamination, thereby further improving the purity of the product.

[0023] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention reasonably adds polyvinyl alcohol as a binder and wollastonite as an expansion agent, and the addition ratios thereof are 0.8%-1.8% and 3.5%-7.8% of the total weight respectively. The selection and dosage of these additives are carefully designed, which not only enhances the bonding force and thermal shock resistance of the material, but also ensures complete decomposition at high temperature without leaving any harmful residue. DETAILED DESCRIPTION

[0024] The following is a more detailed description of the method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of the present invention through specific implementation methods.

[0025] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace of this embodiment selects high-purity magnesium oxide and aluminum oxide powder to ensure that the raw material activity is high and free of impurities, adopts continuous mixer and microwave assisted heating technology, cooperates with hydrogen protective atmosphere, accelerates sintering and prevents the generation of undesirable by-products, and finely grinds and screens to ensure uniform particle size, enhance fluidity, improve adhesion and thermal shock resistance, and ensure no harmful residue at high temperature, significantly improve product performance, and meet the demand for high-performance refractory materials. In this embodiment, it mainly includes the following steps: Step 1: Select raw materials, select magnesium oxide MgO with a purity greater than 99.6% and aluminum oxide micropowder Al2O3 with a purity greater than 99.6%, and ensure that both are highly active and free of impurities. High-purity raw materials can significantly improve the purity and performance of the final product, and have good thermal and chemical stability. Polyvinyl alcohol is used as a binder and wollastonite is used as an expansion agent.

[0027] Step 2: Mix the raw materials, accurately weigh magnesium oxide and aluminum oxide according to a molar ratio of 1:2, and then put the two into a high-speed mixer and mix them evenly for 65 minutes. The magnesium oxide and aluminum oxide are mixed using a continuous mixer to ensure that the two components are completely fused.

[0028] Step 3: Add additives. Add polyvinyl alcohol and wollastonite after the magnesium oxide and aluminum oxide are fully mixed. The addition ratio of polyvinyl alcohol and wollastonite is between 0.8%-1.8% and 3.5%-7.8% of the total weight, respectively. Polyvinyl alcohol can help the material maintain its shape during construction and provide a certain initial strength. The specific amount depends on the required bonding force and construction conditions. If a stronger bonding effect or longer working time is required, the amount can be appropriately increased. Wollastonite is added together with the binder. Wollastonite can compensate for the thermal shrinkage of the material during heating, thereby preventing cracks from forming. The amount added depends on the expected expansion rate and the characteristics of the material used. Excessive use may cause excessive expansion and affect the stability of the structure; insufficient use cannot effectively compensate for shrinkage.

[0029] Step 4: Pre-sintering: Place the mixed powder in a resistance furnace and keep it at 1150°C for 6.5 hours to remove moisture and other volatile substances and promote initial reactions. Then cool naturally to room temperature. Optimized temperature and time parameters help improve the effect of pre-sintering and reduce the generation of undesirable by-products in the subsequent synthesis process.

[0030] Step 5: Synthesis reaction, put the pretreated mixture into a high-temperature electric furnace, and carry out sintering reaction at 1550°C, with a heating rate of 150°C per hour, and maintain a constant temperature for 11 hours after reaching the set temperature. The high-temperature electric furnace sintered the mixture by microwave assisted heating technology. When the high-temperature electric furnace is in use, hydrogen is supplied to it to prevent magnesium oxide from reacting prematurely or generating undesirable by-products. Compared with traditional heating methods, microwave heating can provide more uniform heat distribution and improve the quality of crystal growth. At the same time, the supply of hydrogen can significantly improve the purity and performance of the product.

[0031] Step 6: Material crushing: Use a jaw crusher to crush the block material after synthesis to a maximum particle size of no more than 10mm. Finer particle size is conducive to subsequent fine grinding. Use a ball mill to further refine the material until the average particle size reaches 0.08mm-0.5mm. The grinding medium in the ball mill uses zirconium oxide balls with a ball-to-material ratio of 4:1. This combination not only improves grinding efficiency, but also reduces the risk of metal contamination, further improving the purity of the product.

[0032] Step 7: Screening, the fine powder is graded through a vibrating screen to ensure that the particle size distribution meets the requirements, and the particle size of the powder is controlled to 230-280 mesh. The higher screening accuracy ensures more consistent product quality.

[0033] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by a person of ordinary skill in the field to which the invention belongs. The use of "one" or "an" and other similar words in the specification and claims of this application does not necessarily indicate a quantitative limitation. "Include" or "comprises" and other similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0034] The exemplary implementation modes of the present invention are described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations can be made to the above-mentioned specific embodiments, and various combinations of the technical features and structures proposed in the present invention can be made without exceeding the protection scope of the present invention.

Claims

1. A method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace, characterized in that: The steps include: Step 1: Select raw materials, select magnesium oxide MgO with a purity greater than 99.6% and aluminum oxide micropowder Al2O3 with a purity greater than 99.6%, ensure that both are highly active and free of impurities, select polyvinyl alcohol as a binder, and select wollastonite as an expansion agent; Step 2: Mix the raw materials, accurately weigh magnesium oxide and aluminum oxide according to a molar ratio of 1:2, and then put the two into a high-speed mixer and mix them evenly for 65 minutes; Step 3: Add additives, add polyvinyl alcohol and wollastonite after the magnesium oxide and the aluminum oxide are fully mixed, and the addition ratios of polyvinyl alcohol and wollastonite are respectively between 0.8% and 1.8% and between 3.5% and 7.8% of the total weight; Step 4: Pre-sintering: the mixed powder is placed in a resistance furnace and kept at 1150°C for 6.5 hours to remove moisture and other volatile substances and promote the initial reaction, followed by natural cooling to room temperature; Step 5: Synthesis reaction: put the pretreated mixture into a high-temperature electric furnace and perform sintering reaction at 1550°C with a heating rate of 150°C per hour. After reaching the set temperature, keep the constant temperature for 11 hours. Step 6: Material crushing: Use a jaw crusher to crush the block material after synthesis to a maximum particle size of no more than 10mm, and use a ball mill to further refine the material until the average particle size reaches 0.08mm-0.5mm; Step 7: Screening: The fine powder is graded through a vibrating screen to ensure that the particle size distribution meets the requirements and the particle size of the powder is controlled to be 230-280 mesh.

2. The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace according to claim 1, characterized in that: The magnesium oxide and the aluminum oxide are mixed using a continuous mixer to ensure that the two components are completely blended.

3. The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace according to claim 1, characterized in that: The high temperature electric furnace sintered the mixture by microwave assisted heating technology.

4. The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace according to claim 1, characterized in that: When the high-temperature electric furnace is in use, hydrogen is supplied to the interior thereof to prevent the magnesium oxide from reacting prematurely or generating undesirable byproducts.

5. The method for producing high-purity spinel dry vibration material for steel casting medium frequency furnace according to claim 1, characterized in that: The grinding medium in the ball mill is zirconia balls, and the ball-to-material ratio is 4:1.