A toasting bag drainage sand and a preparation method thereof

Abstract

The application provides a kind of supplementary ladle drainage sand and a preparation method thereof, and belongs to the technical field of steelmaking continuous casting.A kind of supplementary ladle drainage sand is made of the following raw materials by weight: chrome ore sand 0-75 parts, quartz sand 0-75 parts, zircon sand 0-50 parts, fused magnesite 0-50 parts, light-burned dolomite sand 10-25 parts, diatomite 3-7 parts, carbonaceous material 1-3 parts, and contains at least one of chrome ore sand, quartz sand, zircon sand and fused magnesite.The application is used to solve the practical problems of relatively high moisture and low self-opening rate after replacing the upper nozzle of the supplementary ladle, so that the ladle does not need to be baked after replacing the upper nozzle and applying fire clay, and after directly adding the supplementary ladle drainage sand, the phenomenon of self-opening rate reduction caused by the gasification and escape of moisture in the nozzle fire clay does not occur.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking continuous casting technology, specifically relating to a ladle priming sand and its preparation method. Background Technology

[0002] Ladle guide sand is a refractory material used to fill the ladle nozzle. Its function is to allow molten steel, after refining to target requirements, to be poured. During pouring, the ladle slide is opened, and the lower guide sand flows out, forming a cavity in the lower part of the nozzle seat brick. The static pressure of the molten steel breaks through the sintered layer of guide sand on the upper part of the nozzle seat brick, forcing it out of the nozzle and achieving automatic pouring. If the sintered layer of guide sand is too thick, and its compressive strength exceeds the static pressure of the molten steel, the molten steel cannot flow out automatically. An operator must use an oxygen tube to ignite and assist in the flow, a process known as oxygen burning. Oxygen burning has a significant impact on the quality of molten steel, causing problems such as over-oxidation and alloy loss. Most steel produced after oxygen burning faces downgrading or scrapping. Furthermore, the oxygen burning operation poses a risk of burns to operators. If the oxygen burning operation is unsuccessful, it can interrupt continuous pouring, causing huge economic losses and safety hazards to steel companies.

[0003] To improve the automatic start-up rate of steel ladles, industry technicians have optimized ladle scheduling measures, such as shortening the residence time of molten steel and increasing the nozzle diameter. Simultaneously, they have continuously improved the design of the sprue sand, such as adjusting its refractoriness, reducing its thermal conductivity, and adjusting its sintering speed, to enhance its adaptability to the service environment. These measures have generally yielded positive results. However, statistical analysis of the ladle automatic start-up rate shows a significant deficiency for newly commissioned ladles with short baking times and ladles undergoing mid-life nozzle replacements (i.e., reheated ladles or minor repair ladles). Currently, the industry's solutions to the low automatic start-up rate of reheated ladles include minimizing the moisture content of the sprue sand or extending the baking time of the ladle after nozzle replacement, which can improve the automatic start-up rate. However, the actual problems are as follows: (1) The moisture content of the diversion sand product is already very low, usually below 0.5%, and there is very limited room for further reduction. It can only be achieved through strict production control and process upgrades. For diversion sand production enterprises, this means a significant increase in product costs; (2) Extending the ladle baking time not only increases fuel and energy consumption, but also affects the effective scheduling of the ladle and delays the production rhythm. The direct and indirect economic costs are huge.

[0004] Therefore, based on actual production needs, it is also necessary to develop corresponding diversion sand products to address the current situation of relatively high moisture content and low self-opening rate after replacing the water inlet of the baking bag, in order to make up for the shortcoming of low self-opening rate. Summary of the Invention

[0005] In view of this, the present invention provides a priming sand to solve the practical problems of relatively high moisture content and low self-opening rate after the priming ladle is replaced with a water inlet. This allows the ladle to be directly filled with priming sand after the water inlet is replaced and fire putty is applied without baking, and the self-opening rate will not decrease due to the vaporization and escape of moisture from the fire putty inside the water inlet.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a kind of slag for filling and drying bags, which is made from the following raw materials in parts by weight: 0-75 parts of chromite sand, 0-75 parts of quartz sand, 0-50 parts of zircon sand, 0-50 parts of fused magnesia, 10-25 parts of lightly calcined dolomite sand, 3-7 parts of diatomaceous earth, and 1-3 parts of carbonaceous material, and contains at least one of chromite sand, quartz sand, zircon sand and fused magnesia.

[0007] Preferably, the chromite sand contains ≥45% Cr2O3 by weight, ≤28% Fe2O3 by weight, ≤16% Al2O3 by weight, ≤9% MgO by weight, and has a particle size of 0.2mm-0.5mm.

[0008] Preferably, the quartz sand contains ≥95% SiO2 by weight and has a particle size of 0.3mm-1.5mm.

[0009] Preferably, the zircon sand contains ≥58% ZrO2 by weight, ≤38% SiO2 by weight, and has a particle size of 0.1mm-0.5mm.

[0010] Preferably, the fused magnesia contains ≥97% MgO by weight and has a particle size of 0.3mm-1.5mm.

[0011] Preferably, the lightly calcined dolomite sand contains ≥55% MgO by weight, ≥38% CaO by weight, and has a particle size of 0.3mm-1.5mm.

[0012] Preferably, the diatomaceous earth contains ≥88% SiO2 by weight, ≤8% Al2O3 by weight, and has a bulk density ≤0.5 g / cm³. 3 The particle size is 0.1mm-0.5mm.

[0013] Preferably, the carbonaceous material is any one or a mixture of two of carbon black or flake graphite, containing C. 固 The weight percentage is ≥98%.

[0014] Preferably, the effective components of the supplementary baking bag guiding sand are as follows by mass percentage: MgO: 6.0%-65.0%, SiO2: 3.0%-85.0%, ZrO2: 0%-30.0%, Cr2O3: 0%-34.0%, Fe2O3: 0%-21.0%, CaO: 3.5%-10.0%, Al2O3: 0.2%-12.5%, with the remainder being unavoidable impurities.

[0015] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide at least one of chromite sand, quartz sand, zircon sand and fused magnesia, as well as lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportion, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product. The moisture content of the dried product is <0.1%. Cool it naturally to below 60°C to obtain the finished product. Package it according to the required quantity.

[0016] Preferably, the air supply temperature for the drying process is 200℃-450℃.

[0017] The inventors discovered in practice that the self-opening rate of the tundish is generally low. Through long-term in-depth observation and comprehensive analysis, they found that the main reason for the low self-opening rate is that before replacing and installing the tundish nozzle, in order to prevent the "steel penetration" accident during the operation of the ladle, a large amount of fire clay is usually applied to the outer wall of the nozzle core before it is installed into the nozzle seat brick. After the slide plate is closed, the inner cavity of the nozzle becomes a closed space. The moisture in the fire clay is vaporized and dispersed in the high temperature environment inside the ladle nozzle seat brick (the temperature in this area can reach 500-1500℃ when the ladle is filled with steel). It penetrates into the guide sand with extremely high gas partial pressure and forms holes. After the molten steel flows through the holes, it mixes with the guide sand to form a mixture of solidified steel and sintered block (sand), which blocks the nozzle channel and causes the oxygen burning and drainage phenomenon.

[0018] Based on this, this invention, combined with the novel discovery that the large amount of fire clay applied during the replacement of the ladle's upper nozzle causes high moisture content inside the nozzle cavity, introduces two specific materials—diatomite and lightly calcined dolomite—in addition to the conventional chromium, zirconium, or magnesia-based guide sand as the main material. Diatomite, a porous, loose, natural siliceous rock with a refractoriness of 1650-1750℃, is particularly known for its excellent water absorption. In this invention, its function is to absorb excess moisture (vapor) in the inner cavity of the nozzle seat brick, reducing the gas partial pressure of water at high temperatures. Furthermore, its high refractoriness significantly improves the ladle's self-opening rate. Lightly calcined dolomite is obtained by calcining dolomite raw materials at 1000℃ to release gases. It is a porous raw material containing MgO and CaO. In the guide sand of this invention, its main function is to supplement and enhance the water adsorption effect of diatomaceous earth. At the same time, considering that the water content of the fire clay used for ladle baking varies with environmental factors such as weather and production site temperature, if the water content in the inner cavity of some ladle nozzles is too high, the diatomaceous earth in the guide sand cannot be completely adsorbed and will continue to vaporize and diffuse into the guide sand. The CaO component in lightly calcined dolomite has a strong adsorption capacity for water vapor and will quickly undergo hydration upon encountering water vapor, producing cracks. This effectively reduces the gas partial pressure of water and forms uniform cracks inside the guide sand to reduce the compressive strength of the sintered layer, thereby improving the ladle self-opening rate.

[0019] The chromite sand, quartz sand, zircon sand and fused magnesia used in the diversion sand of this invention are all commonly used raw materials in the production of conventional chromite, zircon or magnesia diversion sand, and can be flexibly selected and matched according to the specific steel grades and process requirements of steel enterprises.

[0020] The diversion sand product of this invention can be directly added to the sprue after replacing the sprue nozzle and applying fire clay, without the need for baking. The amount added should be based on the nozzle orifice diameter, enough to fill the nozzle and naturally form a 15cm high sand mound. This diversion sand product can also be used on normally operating ladles.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) Among the raw materials used in the diversion sand of this invention, diatomaceous earth is a highly absorbent refractory material. When combined with lightly calcined dolomite, it forms a complementary effect of low-temperature and high-temperature water absorption, which completely solves the problem of high moisture content in the inner cavity of the sprue seat brick of the repair and baking ladle. After the sprue is replaced, the repair and baking ladle can be used directly with sand without baking, which greatly improves the overall turnover efficiency of the ladle and avoids the decline in self-opening rate caused by excessive moisture in the repair and baking ladle.

[0022] 2) During the heat load of the diversion sand in this invention, after the diatomaceous earth absorbs water, the internal temperature of the diversion sand rises with the heat transfer, and the gas partial pressure of water increases continuously. During the dispersion process, it is absorbed by CaO in the lightly calcined dolomite and quickly hydrates, forming cracks inside the diversion sand. This can reduce the flexural and compressive strength of the sintered layer of the diversion sand, which is conducive to the static pressure of molten steel breaking through the sintered layer to achieve automatic pouring of steel in the ladle.

[0023] 3) The diatomaceous earth used in this invention has a refractoriness of over 1650℃. It is a powdery, porous, and lightweight material with a thermal conductivity of 0.0219 W / m·K at 800℃. When introduced into the diversion sand in an appropriate proportion, it can be uniformly mixed between the diversion sand particles. It is a good heat-resistant and heat-insulating material in the diversion sand, which can effectively reduce the internal heat flux of the diversion sand during the molten steel retention period and delay the occurrence of excessive sintering of the diversion sand. For ladles with complex processing technology and long molten steel retention time, the self-opening rate is significantly improved, reaching about 97%, and the ladle preparation time is shortened to about 12 minutes, with efficiency improved by more than 100%. Detailed Implementation

[0024] To better understand the present invention, the following embodiments further illustrate the content of the invention, but the scope of protection of the present invention is not limited to the following embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0025] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0026] Unless otherwise specified, all raw materials are derived from commercially available products and do not contain any unspecified components other than unavoidable impurities.

[0027] In the following implementation scheme, the chromite sand contains ≥45% by weight of Cr2O3, ≤28% by weight of Fe2O3, ≤16% by weight of Al2O3, ≤9% by weight of MgO, and has a particle size of 0.2mm-0.5mm.

[0028] Quartz sand contains ≥95% SiO2 by weight and has a particle size of 0.3mm-1.5mm.

[0029] Zircon sand contains ≥58% ZrO2 by weight, ≤38% SiO2 by weight, and has a particle size of 0.1mm-0.5mm.

[0030] The fused magnesia contains ≥97% MgO by weight and has a particle size of 0.3mm-1.5mm.

[0031] Lightly calcined dolomite sand contains ≥55% MgO by weight, ≥38% CaO by weight, and has a particle size of 0.3mm-1.5mm.

[0032] Diatomaceous earth contains ≥88% SiO2 by weight, ≤8% Al2O3 by weight, and has a bulk density ≤0.5 g / cm³. 3 The particle size is 0.1mm-0.5mm.

[0033] The calcium slag contains ≥55% CaO by weight, ≤38% Al2O3 by weight, ≤2% SiO2 by weight, and ≤2% MgO by weight.

[0034] Expanded perlite contains ≥70% SiO2 by weight, ≤15% Al2O3 by weight, ≤0.1% H2O by weight, and has a particle size of 0.15mm-0.5mm.

[0035] Carbonaceous materials contain C 固 The weight percentage is ≥98%.

[0036] Example 1: A type of slurry for repairing baking bags, made from the following raw materials in parts by weight: 75 parts chromite sand, 19 parts lightly calcined dolomite sand, 5 parts diatomaceous earth, and 1 part carbonaceous material. The carbonaceous material is carbon black.

[0037] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide chromite sand, lightly calcined dolomite sand and diatomaceous earth, mix them according to the ratio, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 300℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0038] Example 2: A type of slurry sand for baking bags, made from the following raw materials in parts by weight: 75 parts quartz sand, 20 parts lightly calcined dolomite sand, 3 parts diatomaceous earth, and 2 parts carbonaceous material. The carbonaceous material is flake graphite.

[0039] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide quartz sand, lightly calcined dolomite sand and diatomaceous earth, mix them according to the ratio, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 200℃. The moisture content of the dried product is <0.1%. Allow it to cool naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0040] Example 3: A type of slurry sand for baking bags, made from the following raw materials in parts by weight: 40 parts quartz sand, 30 parts zircon sand, 23 parts lightly calcined dolomite sand, 4 parts diatomaceous earth, and 3 parts carbonaceous material. The carbonaceous material is carbon black.

[0041] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide at least one of chromite sand, quartz sand, zircon sand and fused magnesia, as well as lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportion, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 450℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0042] Example 4: A type of slurry for filling baking bags, made from the following raw materials in parts by weight: 15 parts chromite sand, 10 parts quartz sand, 50 parts fused magnesia, 17 parts lightly calcined dolomite sand, 6 parts diatomaceous earth, and 2 parts carbonaceous material. The carbonaceous material is a mixture of carbon black and flake graphite in a weight ratio of 1:1.

[0043] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide at least one of chromite sand, quartz sand, zircon sand and fused magnesia, as well as lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportion, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 260℃. The moisture content of the dried product is <0.1%. Allow it to cool naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0044] Example 5: A type of slurry for baking bags, made from the following raw materials in parts by weight: 50 parts quartz sand, 30 parts fused magnesia, 12 parts lightly calcined dolomite sand, 7 parts diatomaceous earth, and 1 part carbonaceous material. The carbonaceous material is a mixture of carbon black and flake graphite in a weight ratio of 1:3.

[0045] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide quartz sand, fused magnesia, lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportions, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 370℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0046] Example 6: A type of slurry for filling baking bags, made from the following raw materials in parts by weight: 40 parts chromite sand, 40 parts fused magnesia, 10 parts lightly calcined dolomite sand, 7 parts diatomaceous earth, and 3 parts carbonaceous material. The carbonaceous material is a mixture of carbon black and flake graphite in a weight ratio of 3:1.

[0047] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide chromite sand, fused magnesia, lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportions, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 400℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0048] Example 7: A type of slurry for filling baking bags, made from the following raw materials in parts by weight: 50 parts zircon sand, 20 parts fused magnesia, 25 parts lightly calcined dolomite sand, 3 parts diatomaceous earth, and 2 parts carbonaceous material. The carbonaceous material is carbon black.

[0049] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide zircon sand, fused magnesia, lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportions, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 420℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0050] Example 8: A type of slurry for filling baking bags, made from the following raw materials in parts by weight: 53 parts chromite sand, 20 parts quartz sand, 5 parts zircon sand, 15 parts lightly calcined dolomite sand, 6 parts diatomaceous earth, and 1 part carbonaceous material. The carbonaceous material is flake graphite.

[0051] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide chromite sand, quartz sand, zircon sand, lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportions, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 280℃. The moisture content of the dried product is <0.1%. Allow it to cool naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0052] Example 9: A type of slurry for filling baking bags, made from the following raw materials in parts by weight: 30 parts chromite sand, 18 parts quartz sand, 20 parts zircon sand, 5 parts fused magnesia, 5 parts lightly calcined dolomite sand, 21 parts diatomaceous earth, and 4 parts carbonaceous material. The carbonaceous material is flake graphite.

[0053] The preparation method of the above-mentioned supplementary baking bag drainage sand includes the following steps: Step S1: Provide chromite sand, quartz sand, zircon sand, fused magnesia, lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportions, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product with an air supply temperature of 350℃. The moisture content of the dried product is <0.1%. Cool it naturally to below 60℃ to obtain the finished product, which is then measured and packaged as needed.

[0054] The effective components of the drainage sand prepared in Examples 1-9 above are shown in the table below: Comparative Example 1: This comparative example is a type of drainage sand, which differs from Example 1 in that diatomaceous earth is omitted, and the amount of lightly calcined dolomite sand is 24 parts by weight. The remaining raw materials and their weight parts are the same as in Example 1. The preparation method is the same as in Example 1.

[0055] Comparative Example 2: This comparative example is a type of drainage sand, which differs from Example 2 in that diatomaceous earth is omitted, and the amount of lightly calcined dolomite sand is 23 parts by weight. The remaining raw materials and their weight proportions are the same as in Example 2. The preparation method is the same as in Example 2.

[0056] Comparative Example 3: This comparative example is a type of drainage sand, which differs from Example 3 in that it contains 10 parts by weight of lightly calcined dolomite sand and 17 parts by weight of diatomaceous earth, while the remaining raw materials and their weight proportions are the same as in Example 3. The preparation method is the same as in Example 3.

[0057] Comparative Example 4: This comparative example is a type of drainage sand, which differs from Example 4 in that it contains 9 parts by weight of lightly calcined dolomite sand and 14 parts by weight of diatomaceous earth, while the remaining raw materials and their weight proportions are the same as in Example 4. The preparation method is the same as in Example 4.

[0058] Comparative Example 5: This comparative example is a type of drainage sand, which differs from Example 5 in that: lightly calcined dolomite sand is omitted, diatomaceous earth is 19 parts by weight, and the remaining raw materials and their weight parts are the same as in Example 5. Its preparation method is the same as in Example 5.

[0059] Comparative Example 6: This comparative example is a type of drainage sand, which differs from Example 6 in that diatomaceous earth is omitted, 17 parts by weight of lightly calcined dolomite sand is used, and the remaining raw materials and their weight proportions are the same as in Example 6. Its preparation method is the same as in Example 6.

[0060] Comparative Example 7: This comparative example is a type of diversion sand, which differs from Example 7 in that calcium slag is used instead of lightly calcined dolomite sand. Its preparation method is the same as in Example 7.

[0061] Comparative Example 8: This comparative example is a drainage sand, which differs from Example 8 in that expanded perlite is used instead of diatomaceous earth. Its preparation method is the same as in Example 8.

[0062] Comparative Example 9: This comparative example is a type of drainage sand, which differs from Example 9 in that it contains 8 parts by weight of lightly calcined dolomite sand, 17 parts by weight of diatomaceous earth, and the remaining raw materials and their weight proportions are the same as in Example 9. Its preparation method is the same as in Example 9.

[0063] The effective components of the drainage sand prepared in Comparative Examples 1-9 above are shown in the table below: The drainage sand prepared in Examples 1-9 and Comparative Examples 1-9 was used for drainage operations of different supplementary baking bags, and the preparation time and self-opening rate of the supplementary baking bags in the drainage operations were statistically analyzed.

[0064] Ladle preparation time refers to the period from the start of hot repairs on the ladle (including nozzle replacement) to the completion of sand addition and readiness for casting. This time interval includes ladle maintenance, preparation work, and the final sand addition operation, and is a crucial step in the continuous casting process. The length of ladle preparation time affects the steel plant's production efficiency and the casting rhythm of the continuous casting machine. A prolonged preparation time may cause the continuous casting machine to wait, disrupting the continuity of the production process. Therefore, steel plants typically strive to minimize ladle preparation time to improve production efficiency.

[0065] The experimental and statistical results of this invention are as follows: The above data shows that, under the same number of test furnaces, the self-opening rate of the diversion sand of the present invention is significantly improved, averaging about 97%. At the same time, under the condition of a higher self-opening rate, the preparation time of the diversion sand of the present invention for the seat bricks of the refilling ladle is shorter, averaging less than 12 minutes, which is at least half the time of the comparative example, and the operating efficiency is more than doubled, showing significant superiority.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A type of drainage sand for repairing baking bags, characterized in that: It is made from the following raw materials in parts by weight: 0-75 parts chromite sand, 0-75 parts quartz sand, 0-50 parts zircon sand, 0-50 parts fused magnesia, 10-25 parts lightly calcined dolomite sand, 3-7 parts diatomite, and 1-3 parts carbonaceous material, and contains at least one of chromite sand, quartz sand, zircon sand and fused magnesia.

2. The drainage sand for repairing baking bags as described in claim 1, characterized in that: The chromite sand contains ≥45% Cr2O3 by weight, ≤28% Fe2O3 by weight, ≤16% Al2O3 by weight, and ≤9% MgO by weight, with a particle size of 0.2mm-0.5mm.

3. The drainage sand for repairing baking bags as described in claim 2, characterized in that: The quartz sand contains ≥95% SiO2 by weight and has a particle size of 0.3mm-1.5mm.

4. The drainage sand for repairing baking bags as described in claim 3, characterized in that: The zircon sand contains ≥58% ZrO2 by weight, ≤38% SiO2 by weight, and has a particle size of 0.1mm-0.5mm.

5. The drainage sand for repairing baking bags as described in claim 4, characterized in that: The fused magnesia contains ≥97% MgO by weight and has a particle size of 0.3mm-1.5mm.

6. The drainage sand for repairing baking bags as described in claim 5, characterized in that: The lightly calcined dolomite sand contains ≥55% MgO by weight, ≥38% CaO by weight, and has a particle size of 0.3mm-1.5mm.

7. The drainage sand for repairing baking bags as described in claim 6, characterized in that: The diatomaceous earth contains ≥88% SiO2 by weight, ≤8% Al2O3 by weight, and has a bulk density ≤0.5 g / cm³. 3 The particle size is 0.1mm-0.5mm.

8. The drainage sand for repairing baking bags as described in claim 7, characterized in that: The carbonaceous material is any one or a mixture of two of carbon black or flake graphite, containing C. 固 The weight percentage is ≥98%.

9. The drainage sand for repairing baking bags as described in claim 8, characterized in that: The effective components of the supplementary baking bag diverting sand are as follows by mass percentage: MgO: 6.0%-65.0%, SiO2: 3.0%-85.0%, ZrO2: 0%-30.0%, Cr2O3: 0%-34.0%, Fe2O3: 0%-21.0%, CaO: 3.5%-10.0%, Al2O3: 0.2%-12.5%, with the remainder being unavoidable impurities.

10. A method for preparing a supplementary baking bag drainage sand as described in any one of claims 1-9, characterized in that: Includes the following steps: Step S1: Provide at least one of chromite sand, quartz sand, zircon sand and fused magnesia, as well as lightly calcined dolomite sand and diatomaceous earth, mix them according to the proportion, stir to obtain a mixture; Step S2: Add carbonaceous material to the mixture and stir again to obtain a semi-finished product; Step S3: Dry the semi-finished product. The moisture content of the dried product is <0.1%. Cool it naturally to below 60°C to obtain the finished product. Package it according to the required quantity.

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