Chromium drainage agent for electrical steel and preparation method of chromium drainage agent

Abstract

The invention discloses an electrical steel chromium drainage agent and a preparation method thereof, and belongs to the technical field of metallurgical auxiliary materials, and the preparation method of the drainage agent comprises the following steps: weighing chromium sand A, chromium sand B, desert sand, ceramsite and a functional agent, feeding into a belt weigher, re-checking, mixing and stirring, adding water, medium carbon graphite and carbon black, stirring, and drying. The functional agent is formed by mixing graphene, forsterite powder, silicon nitride and titanium boride, and aims at improving the self-opening rate and optimizing the refractoriness. Compared with the prior art, the obtained drainage agent has the excellent self-opening rate and is suitable for the continuous casting process of electrical steel, and the production efficiency and the molten steel quality are improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical auxiliary materials, and in particular to a chromium drainage agent for electrical steel and a preparation method thereof. Background Art

[0002] In the field of metallurgical auxiliary materials technology, electrical steel is an indispensable soft magnetic material in the power industry, and its production efficiency and product quality have always been highly valued by the industry. In the production process of electrical steel, drainage agents play a vital role, which directly affects the fluidity of molten steel and the self-opening rate of the ladle, thereby affecting the quality of steel and production efficiency.

[0003] At present, the existing chromium drainers for electrical steel on the market usually have some problems. For example, Chinese invention patent CN109202055A discloses a high-quality steel drainer and its preparation method, which belongs to the technical field of metallurgical refractory materials. A high-quality steel drainer is made of the following raw materials in parts by weight: 22 to 75 parts of natural zircon sand with a particle size of 0.1 to 0.5 mm, 8 to 40 parts of chromium ore sand with a particle size of 0.1 to 0.5 mm, 15 to 35 parts of desert sand with a particle size of 0.3 to 0.6 mm, and 1 to 3 parts of liquid graphite. The high-quality steel drainer of the invention can effectively improve the product pouring rate. Compared with the existing drainers, the self-opening rate can be increased by more than 10%, and the basic self-opening rate can reach 100%. This method meets the needs of existing special steel grades with many different components and long smelting time, especially for military, nuclear power and special fine steel grades. Although this method meets the production needs to a certain extent, the self-opening rate and refractoriness of the drainage agent prepared by it at high temperature are still not ideal. This is mainly because the components and preparation process of the drainage agent in the existing technology fail to fully consider the performance requirements under high temperature and high flow conditions, resulting in the drainage agent being prone to rapid wear and insufficient refractoriness in actual applications, which limits its use in certain high-temperature operation scenarios.

[0004] In addition, another limitation of the prior art is that the raw material ratio and drying process in the preparation method are not precisely controlled, resulting in large fluctuations in the performance of the final product, which cannot meet the increasingly stringent industrial standards. Therefore, developing a chromium drainage agent for electrical steel with a higher self-opening rate and better refractoriness, while ensuring the consistency and stability of product quality, has become a technical problem that urgently needs to be solved in the industry. Summary of the invention

[0005] In view of the defects of the prior art, the present invention aims to provide a chromium drainage agent for electrical steel and a preparation method thereof, so as to solve the problem of insufficient performance of the drainage agent in the prior art. The present invention improves the fluidity of molten steel and the self-opening rate of the ladle through a carefully designed raw material ratio and preparation process, and introduces a specific functional agent, thereby ensuring stability and durability in a high-temperature operating environment.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A method for preparing a chromium drainage agent for electrical steel is as follows, in parts by weight: Step 1, weigh chrome sand A, chrome sand B, desert sand, and gemstone sand into a belt scale, and then enter the mixer after a second check of the belt scale to start mixing; start adding water after all the materials from the silo are put into the mixer; stir for 1 to 5 minutes after adding water, add medium carbon graphite and carbon black, stir for 5 to 10 minutes, and then put them into the mixer; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean and dry in the drying tower. If the moisture content exceeds the limit, it will be considered unqualified and will be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel.

[0007] The weight proportions of the substances are 40-60 parts of chromium sand A, 20-40 parts of chromium sand B, 5-15 parts of desert sand, 5-15 parts of gemstone sand, 0.5-0.7 parts of medium carbon graphite, 0.3-0.5 parts of carbon black, and 10-20 parts of water.

[0008] Preferably, the preparation method of the chromium drainage agent for electrical steel is: Step 1, weigh chrome sand A, chrome sand B, desert sand, gem sand, and functional agent into a belt scale, and then enter the mixer once after the belt scale is double-checked, and start stirring; after all the materials from the silo are put into the mixer, start adding water; after adding water, stir for 1 to 5 minutes, add medium carbon graphite and carbon black, stir for 5 to 10 minutes, and then put it down; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean and dry in the drying tower. If the moisture content exceeds the limit, it will be considered unqualified and will be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel.

[0009] The weight proportions of the substances are 40-60 parts of chromium sand A, 20-40 parts of chromium sand B, 5-15 parts of desert sand, 5-15 parts of gem sand, 0.1-0.3 parts of functional agent, 0.5-0.7 parts of medium carbon graphite, 0.3-0.5 parts of carbon black, and 10-20 parts of water.

[0010] The drying tower is used for drying, and the drying temperature is 400-600°C and the exhaust air temperature is 110-150°C.

[0011] The functional agent is a mixture of graphene, forsterite powder, silicon nitride and titanium boride in a mass ratio of 0.5-2:2-4:2-4:2-4.

[0012] The moisture content exceeding 0.3% is considered unqualified.

[0013] The particle size of the chrome sand A is 20-70 meshes; the particle size of the chrome sand B is 20-80 meshes; and the particle size of the desert sand is 0.4-0.9 mm.

[0014] In the preparation method of the chromium draining agent for electrical steel of the present invention, the functions of various substances are as follows: Chrome sand A and Chrome sand B are the main components of drainage agent, providing necessary chemical composition and physical properties such as fire resistance and wear resistance. Chromium can improve the high temperature resistance and corrosion resistance of the material.

[0015] Desert sand may be selected because of its purity and particle size distribution, which helps improve the flow and filling properties of the drainage agent.

[0016] The jelly sand helps to improve the flow of the mixture, reduce friction, and may improve the filling performance of the drainage agent.

[0017] The functional agent includes graphene, forsterite powder, silicon nitride, and titanium boride. This combination is intended to enhance the high-temperature performance and self-opening rate of the drainage agent.

[0018] As a part of the functional agent, graphene can help reduce the flow resistance of molten steel and improve the self-opening rate due to its excellent thermal conductivity and lubricity.

[0019] Forsterite powder provides good fire resistance and thermal shock resistance, helping to maintain the structural integrity of the drainage agent at high temperatures.

[0020] Silicon nitride enhances the chemical stability and wear resistance of the material, slowing down the wear of the material at high temperatures.

[0021] Titanium boride increases hardness and strength, providing excellent wear resistance.

[0022] Water Water added during the mixing process may be used to adjust the viscosity of the mixture and improve fluidity, aiding the mixing and shaping process.

[0023] The addition of medium carbon graphite and carbon black may be intended to improve the thermal stability and electrical conductivity of the mixture, and may also help control the sintering process of the flow-discharging agent.

[0024] Drying is to remove moisture from the mixture and ensure that the final product of the drainage agent has good thermal properties and structural strength.

[0025] Through this preparation method, the synergistic effect of each component is aimed at improving the performance of the chromium drain additive for electrical steel, especially the self-opening rate and refractoriness at high temperatures, which are crucial for the continuous casting of molten steel.

[0026] Compared with the prior art, it has the following beneficial effects: 1) By adding a specific functional agent, the chromium drain agent for electrical steel of the present invention achieves a higher self-opening rate and a more ideal refractoriness; this improvement means that the drain agent can more effectively guide the flow of molten steel during the molten steel casting process, reduce blockage and stagnation, and maintain structural integrity at high temperatures, thereby improving production efficiency and molten steel quality.

[0027] 2) The present invention optimizes the performance of the drainage agent by precisely controlling the raw material ratio and the preparation process, so that the obtained electrical steel chromium drainage agent exhibits better fluidity and self-opening rate during the molten steel casting process, while ensuring stability and durability in a high-temperature operating environment, thereby improving the drainage efficiency and molten steel quality and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the appearance of the chromium drainage agent for electrical steel prepared in Example 1. DETAILED DESCRIPTION

[0029] Main sources of substances: Chrome sand A: particle size is 20~70 mesh.

[0030] Chrome sand B: particle size is 20~80 mesh.

[0031] Desert sand: particle size is 0.4~0.9mm.

[0032] Baozhu sand: particle size is 40~70 mesh.

[0033] Medium carbon graphite: fixed carbon content 90-94%, volatile matter ≤2.5%, moisture ≤0.5%; particle size: 325 mesh.

[0034] Carbon black: Product No.: GB-0814, Ningbo Yushun Plastic Chemical Co., Ltd.

[0035] Graphene: surface area > 500 m 2 / g, thickness: <3 layers, lateral size: 0.5-5 μm, purchased from Merck.

[0036] Forsterite powder: Item No.: 1585, Hebei Zongrun Mineral Products Co., Ltd.

[0037] Silicon nitride: Model: ZZY-Si3N4, Particle size: 150-325 mesh, Qinghe County Zhongzhou Alloy Material Co., Ltd.

[0038] Titanium boride: particle size: 200 mesh, brand: TiB2, Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0039] The design idea of ​​the present invention is to optimize the performance of the chromium drain agent for electrical steel by using a specific combination of functional agents, especially to improve the self-opening rate and refractoriness. By carefully selecting and proportioning the four materials of graphene, forsterite powder, silicon nitride and titanium boride, the invention aims to combine the unique properties of each component to achieve a synergistic effect, thereby improving the performance of the drain agent under high temperature and high flow conditions. Graphene is selected for its excellent thermal conductivity and lubricity, which helps to reduce the flow resistance of molten steel and improve the self-opening rate; forsterite powder provides the material with high temperature stability due to its good refractoriness and thermal shock resistance; silicon nitride and titanium boride enhance the high temperature performance and wear resistance of the material with their high hardness and wear resistance. Mixing according to a specific mass ratio is intended to balance the properties of these materials to ensure that the drain agent has good fluidity during the molten steel casting process and can maintain structural integrity and performance stability at high temperatures. Through the functional agent ratio guided by the principles of material science, the comprehensive performance of the chromium drain agent for electrical steel is optimized to meet the needs of efficient and stable steel production. Example 1

[0040] A method for preparing a chromium drainage agent for electrical steel: Step 1, weigh 500kg chrome sand A, 300kg chrome sand B, 100kg desert sand, and 100kg gem sand into the belt scale, and then enter the mixer once after the belt scale is double-checked, and start stirring; after all the materials from the silo are put into the mixer, start adding 20kg water; after adding water, stir for 3 minutes, add 6kg medium carbon graphite and 4kg carbon black, stir for 10 minutes, and then put it down; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean. The drying tower temperature is 500°C, and the exhaust temperature is 130°C. The moisture content after drying and cooling should not be higher than 0.30%. If the moisture content exceeds this limit, it will be deemed unqualified and must be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel. Example 2

[0041] A method for preparing a chromium drainage agent for electrical steel: Step 1, weigh 500kg chrome sand A, 300kg chrome sand B, 100kg desert sand, 100kg gem sand, and 2kg functional agent into a belt scale, and then enter the mixer once after the belt scale is double-checked, and start stirring; after all the materials from the silo are put into the mixer, start adding 20kg water; after adding water, stir for 3 minutes, add 6kg medium carbon graphite and 4kg carbon black, stir for 10 minutes, and then put it down; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean. The drying tower temperature is 500°C, and the exhaust temperature is 130°C. The moisture content after drying and cooling should not be higher than 0.30%. If the moisture content exceeds this limit, it will be deemed unqualified and must be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel.

[0042] The functional agent is a mixture of 0.2 kg of graphene, 0.6 kg of forsterite powder, 0.6 kg of silicon nitride, and 0.6 kg of titanium boride. Example 3

[0043] The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0044] The functional agent is a mixture of 0.2 kg of graphene, 0.4 kg of forsterite powder, 0.7 kg of silicon nitride, and 0.7 kg of titanium boride. Example 4

[0045] The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0046] The functional agent is a mixture of 0.2 kg of graphene, 0.8 kg of forsterite powder, 0.5 kg of silicon nitride, and 0.5 kg of titanium boride.

[0047] Comparative Example 1 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0048] The functional agent is a mixture of 0.6667 kg of forsterite powder, 0.6667 kg of silicon nitride, and 0.6667 kg of titanium boride.

[0049] Comparative Example 2 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0050] The functional agent is a mixture of 0.2 kg of graphene, 0.9 kg of silicon nitride and 0.9 kg of titanium boride.

[0051] Comparative Example 3 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0052] The functional agent is a mixture of 0.2 kg of graphene, 0.9 kg of forsterite powder, and 0.9 kg of titanium boride.

[0053] Comparative Example 4 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0054] The functional agent is a mixture of 0.2 kg of graphene, 0.9 kg of forsterite powder, and 0.9 kg of silicon nitride.

[0055] Comparative Example 5 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0056] The functional agent is a mixture of 0.2 kg of graphene and 1.8 kg of forsterite powder.

[0057] Comparative Example 6 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0058] The functional agent is a mixture of 0.2 kg of graphene and 1.8 kg of silicon nitride.

[0059] Comparative Example 7 The preparation method of a chromium drainage agent for electrical steel is basically the same as that of Example 2, the only difference being the difference in the functional agent.

[0060] The functional agent is a mixture of 0.2 kg of graphene and 1.8 kg of titanium boride.

[0061] Test Example 1 The chromium drainage agent for electrical steel produced by the schemes of the embodiment and the comparative example is used in a steel plant, the ladle capacity is 150T, the inner diameter of the water nozzle is 60mm, the steel type is electrical steel, the refining method is RH (vacuum degassing), the steel waiting time is 1 to 10 hours, and the average self-opening rate over three months is calculated.

[0062] The test results are shown in Table 1.

[0063] Table 1 Experimental protocol Self-opening rate (%) Example 1 96.2 Example 2 99.7 Example 3 98.4 Example 4 98.3 Comparative Example 1 97.5 Comparative Example 2 97.6 Comparative Example 3 97.4 Comparative Example 4 97.6 Comparative Example 5 97.0 Comparative Example 6 97.1 Comparative Example 7 96.9 Test Example 2 Folding resistance: The test was conducted using a paper folding resistance tester (Jinan Sanquan Zhongshi Experimental Instrument Co., Ltd., China). Test parameters: At room temperature, paper cut into 5cm×1cm pieces was folded back and forth until the paper broke.

[0064] The test results are shown in Table 2.

[0065] Table 2 Experimental protocol Refractoriness (℃) Example 1 1668 Example 2 1754 Example 3 1798 Example 4 1712 Comparative Example 1 1694 Comparative Example 2 1777 Comparative Example 3 1774 Comparative Example 4 1732 Comparative Example 5 1721 Comparative Example 6 1735 Comparative Example 7 1804 It can be seen from the data in Tables 1 and 2 that the chromium drainage agent for electrical steel prepared in Example 2 has the highest self-opening rate and more suitable refractoriness.

[0066] The reason why the functional agent ratio in Example 2 (0.2kg graphene, 0.6kg forsterite powder, 0.6kg silicon nitride, and 0.6kg titanium boride) can bring a higher self-opening rate and a more ideal refractoriness may be that this specific combination and ratio produce the best synergistic effect. The addition of graphene provides excellent thermal conductivity and lubricity, which helps to reduce the flow resistance of molten steel, improve fluidity, and thus improve the self-opening rate. Forsterite powder provides good refractoriness and thermal shock resistance, which helps to maintain the structural integrity of the drainage agent at high temperatures. The addition of silicon nitride and titanium boride further enhances the high temperature performance and wear resistance of the material. This specific mass ratio may optimize the balance between the thermal and mechanical properties of the material, making the performance of the drainage agent more outstanding under the harsh conditions of high temperature and molten steel flushing. Forsterite powder, silicon nitride and titanium boride may provide better refractoriness and structural strength, while the proportion of graphene provides the required thermal lubricity just right, without excessively increasing or reducing any one component, thereby avoiding possible negative effects.

[0067] Forsterite powder has excellent fire resistance and thermal shock resistance, and can effectively improve the stability of materials at high temperatures. When forsterite powder coexists with silicon nitride and titanium boride, a synergistic effect may occur, in which forsterite powder provides a good refractory substrate, which helps to maintain physical stability at high temperatures of molten steel. Silicon nitride enhances the chemical stability and wear resistance of the material, and slows down the wear of the material at high temperatures. Titanium boride further enhances hardness and strength, and provides excellent wear resistance. This synergistic effect may make the functional agent of Example 2 more effective in improving the self-opening rate, because the addition of forsterite powder balances the lubricating effect of graphene, and the addition of silicon nitride and titanium boride improves the refractoriness and wear resistance of the material. In contrast, lack of forsterite powder or lack of silicon nitride and titanium boride may not achieve the same high temperature stability and wear resistance, thereby affecting the self-opening rate and refractoriness. Therefore, the synergistic effect of forsterite powder with silicon nitride and titanium boride may be the key reason why Example 2 shows better performance.

Claims

1. A method for preparing a chromium drainage agent for electrical steel, characterized in that: The method is as follows, in parts by weight: Step 1, weigh chrome sand A, chrome sand B, desert sand, and gemstone sand into a belt scale, and then enter the mixer after a second check of the belt scale to start mixing; start adding water after all the materials from the silo are put into the mixer; stir for 1 to 5 minutes after adding water, add medium carbon graphite and carbon black, stir for 5 to 10 minutes, and then put them into the mixer; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean and dry in the drying tower. If the moisture content exceeds the limit, it will be considered unqualified and will be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel.

2. The method for preparing the chromium drainage agent for electrical steel according to claim 1, characterized in that: The weight proportions of the substances are 40-60 parts of chromium sand A, 20-40 parts of chromium sand B, 5-15 parts of desert sand, 5-15 parts of gemstone sand, 0.5-0.7 parts of medium carbon graphite, 0.3-0.5 parts of carbon black, and 10-20 parts of water.

3. The method for preparing the chromium drainage agent for electrical steel according to claim 1, characterized in that: The preparation method of the chromium drainage agent for electrical steel: Step 1, weigh chrome sand A, chrome sand B, desert sand, gem sand, and functional agent into a belt scale, and then enter the mixer once after the belt scale is double-checked, and start stirring; after all the materials from the silo are put into the mixer, start adding water; after adding water, stir for 1 to 5 minutes, add medium carbon graphite and carbon black, stir for 5 to 10 minutes, and then put it down; Step 2: Before drying, ensure that the site, storage tanks, cyclone dust collectors, passages, slag coolers, belts, elevators, and finished product tanks are clean and dry in the drying tower. If the moisture content exceeds the limit, it will be considered unqualified and will be returned for re-drying. The qualified product is the chromium drainage agent for electrical steel.

4. The method for preparing the chromium drainage agent for electrical steel according to claim 3, characterized in that: The weight proportions of the substances are 40-60 parts of chromium sand A, 20-40 parts of chromium sand B, 5-15 parts of desert sand, 5-15 parts of gem sand, 0.1-0.3 parts of functional agent, 0.5-0.7 parts of medium carbon graphite, 0.3-0.5 parts of carbon black, and 10-20 parts of water.

5. The method for preparing the chromium drainage agent for electrical steel according to claim 3, characterized in that: The functional agent is a mixture of graphene, forsterite powder, silicon nitride and titanium boride in a mass ratio of 0.5-2:2-4:2-4:2-4.

6. The method for preparing the chromium drainage agent for electrical steel according to claim 1 or 3, characterized in that: The drying tower is used for drying, and the drying temperature is 400-600°C and the exhaust air temperature is 110-150°C.

7. The method for preparing the chromium drainage agent for electrical steel according to claim 1 or 3, characterized in that: The moisture content exceeding 0.3% is considered unqualified.

8. The method for preparing the chromium drainage agent for electrical steel according to claim 1 or 3, characterized in that: The particle size of the chrome sand A is 20-70 meshes; the particle size of the chrome sand B is 20-80 meshes; and the particle size of the desert sand is 0.4-0.9 mm.

9. A chromium drainage agent for electrical steel, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

Images