An annealing release agent for oriented silicon steel and a method for preparing the same

Abstract

The application relates to the technical field of silicon steel processing process, and discloses an oriented silicon steel magnesium oxide annealing release agent and a preparation method thereof. The oriented silicon steel magnesium oxide annealing release agent comprises the following components in mass parts: epoxy propyl alcohol modified magnesium oxide 40-240 parts, titanium dioxide 2-6 parts, boric acid 1-3 parts and water 320-2400 parts. Through the technical scheme, the problem that the oriented silicon steel magnesium oxide in related technology has poor suspensibility in water, easily forms a precipitate, and thus causes the magnetic performance of the oriented silicon steel to be poor and the iron loss to increase is solved.

Description

Technical Field

[0001] This invention relates to the field of silicon steel processing technology, specifically to a magnesium oxide annealing release agent for oriented silicon steel and its preparation method. Background Technology

[0002] Grain-oriented silicon steel is an important product in the national strategic development materials list, and is a core component or core material for the power industry and transformers. The magnesium coating and high-temperature annealing process for grain-oriented silicon steel serves as an insulating layer, ensuring the surface quality of the steel and is a crucial step in its production.

[0003] Magnesium oxide in oriented silicon steel possesses excellent magnetic permeability and insulation properties, enabling the formation of a good insulating layer and magnetic medium on the surface of silicon steel sheets to suppress and overcome eddy currents and iron losses in the silicon steel core of transformers. However, existing magnesium oxide in oriented silicon steel has poor suspension properties in water. When mixed with water to form a slurry for coating, it easily forms sediment, resulting in uneven coating and affecting the magnetic properties and iron losses of the oriented silicon steel. Summary of the Invention

[0004] This invention proposes an annealing isolator for magnesium oxide in oriented silicon steel and its preparation method, which solves the problem in related technologies that magnesium oxide in oriented silicon steel has poor suspension in water and is prone to precipitation, resulting in poor magnetic properties and increased iron loss in oriented silicon steel.

[0005] The technical solution of the present invention is as follows:

[0006] An annealing release agent for oriented silicon steel magnesium oxide comprises the following components in parts by weight: 40-240 parts of glycidol-modified magnesium oxide, 2-6 parts of titanium dioxide, 1-3 parts of boric acid, and 320-2400 parts of water.

[0007] In this invention, glycidol-modified magnesium oxide, titanium dioxide, boric acid, and water are used as components of the magnesium oxide annealing release agent for grain-oriented silicon steel. Glycidol-modified magnesium oxide plays a crucial role in the annealing process of silicon steel, acting not only as a physical release agent but also reacting with the silica on the silicon steel surface to form a magnesium silicate insulating layer, significantly improving the insulation performance of the silicon steel, reducing current leakage and energy loss, and increasing equipment efficiency. Furthermore, it can remove impurities such as nitrogen and sulfur from the steel, improving the purity and magnetic properties of the silicon steel. Titanium dioxide decomposes into oxygen during high-temperature annealing, improving the atmosphere between steel strips. The oxygen can combine with aluminum diffused from the steel, preventing aluminum from damaging the silica film, thus ensuring the formation of a good magnesium silicate underlayer, improving the adhesion of the underlayer, and enhancing the underlayer's ability to absorb nitrogen. Boric acid acts as a regulator in the annealing release agent; water is used to adjust the viscosity and flowability of the annealing release agent. By optimizing the components and their dosage, the magnesium oxide annealing release agent for grain-oriented silicon steel exhibits excellent comprehensive performance.

[0008] As a further technical solution, the magnesium oxide in the glycidol-modified magnesium oxide is spherical magnesium oxide.

[0009] As a further technical solution, the spherical magnesium oxide is composed of spherical magnesium oxide with a particle size of 50-200 nm and spherical magnesium oxide with a particle size of 250-300 nm in a mass ratio of 3:7 to 1:1, and preferably is composed of spherical magnesium oxide with a particle size of 100 nm and spherical magnesium oxide with a particle size of 300 nm in a mass ratio of 2:3.

[0010] In this invention, the raw materials for propylene oxide-modified magnesium oxide include magnesium oxide and propylene oxide in a mass-to-volume ratio of 1g:1~3mL. For example, the mass-to-volume ratio of magnesium oxide to propylene oxide can be 1g:1mL, 1g:1.5mL, 1g:2mL, 1g:2.5mL or 1g:3mL, and the preferred mass-to-volume ratio of magnesium oxide to propylene oxide is 1g:1.5~2.5mL.

[0011] As a further technical solution, the preparation method of the glycidol-modified magnesium oxide includes the following steps: mixing magnesium oxide, catalyst, glycidol and solvent, modifying, filtering and collecting the solid, washing, drying, and obtaining glycidol-modified magnesium oxide.

[0012] In this invention, during the preparation of propylene oxide-modified magnesium oxide, magnesium oxide, catalyst, propylene oxide, and solvent are mixed and then modified. During the modification process, in the presence of the catalyst, the epoxy groups in the propylene oxide react with the hydroxyl groups on the surface of magnesium oxide, thereby grafting onto the surface of magnesium oxide. The modified magnesium oxide is collected by filtration, then washed to remove the catalyst and high-boiling-point solvent, and finally dried to remove the detergent, thus obtaining propylene oxide-modified magnesium oxide.

[0013] As a further technical solution, the catalyst is a tertiary amine.

[0014] As a further technical solution, the mass ratio of magnesium oxide to catalyst is 1:0.01~0.05, and the mass-volume ratio of magnesium oxide to solvent is 1g:15~25mL.

[0015] As a further technical solution, the modification temperature is 110~130℃, and the modification time is 2~5h.

[0016] As a further technical solution, the washing process specifically involves using ethanol for washing.

[0017] As a further technical solution, the following components by weight are also included: 0.5 to 5 parts of sodium polyacrylate.

[0018] In this invention, sodium polyacrylate is added. Sodium polyacrylate acts as a dispersant, further improving the suspension of magnesium oxide in water, thereby further enhancing the magnetic properties of the grain-oriented silicon steel and further reducing iron loss. This is because, after adding sodium polyacrylate, it adsorbs onto the surface of the magnesium oxide particles, greatly reducing the attractive force between particles, preventing particle aggregation and sedimentation, which would otherwise affect the magnetic properties of the grain-oriented silicon steel and increase iron loss.

[0019] As a further technical solution, the mass ratio of the glycidol-modified magnesium oxide to the sodium polyacrylate is 200:1.5~3.

[0020] The present invention further specifies that the mass ratio of glycidol-modified magnesium oxide to sodium polyacrylate is 200:1.5~3, which further improves the quality and adhesion of the coating.

[0021] The present invention also proposes a method for preparing a magnesium oxide annealing release agent for oriented silicon steel, which includes the following steps: mixing raw materials evenly to obtain the magnesium oxide annealing release agent for oriented silicon steel.

[0022] The working principle and beneficial effects of this invention are as follows:

[0023] This invention adds glycidol to modify magnesium oxide, increasing the hydrophilicity of the magnesium oxide surface and thus improving the suspension of magnesium oxide in water, thereby enhancing the magnetic properties of grain-oriented silicon steel and reducing iron loss. The reason is that the epoxy groups in glycidol react with the hydroxyl groups on the magnesium oxide surface, achieving hydrophilic surface modification of magnesium oxide. Although hydroxyl groups are consumed during the modification process, the number of hydroxyl groups on the surface of modified magnesium oxide increases compared to unmodified magnesium oxide, because glycidol itself contains hydroxyl groups, and the reaction between epoxy groups and hydroxyl groups also generates hydroxyl groups. Therefore, the modified magnesium oxide has increased hydrophilic groups on its surface, thus increasing its hydrophilicity, making it less prone to aggregation and more dispersible in water, thereby improving the magnetic properties of grain-oriented silicon steel and reducing iron loss. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples: magnesium oxide is composed of spherical magnesium oxide with a particle size of 100 nm and spherical magnesium oxide with a particle size of 300 nm in a mass ratio of 2:3.

[0026] Example 1

[0027] A1. Magnesium oxide, benzyl dimethylamine, and glycidol were added to N,N-dimethylformamide and mixed (the ratio of magnesium oxide, benzyl dimethylamine, glycidol, and N,N-dimethylformamide was 1g:0.01g:1.5mL:15mL). The mixture was stirred at 500rpm and reacted at 110℃ for 5h. After filtration, the solid was washed with ethanol and dried to obtain glycidol-modified magnesium oxide.

[0028] A2. Mix 100 parts of glycidol-modified magnesium oxide, 6 parts of titanium dioxide, 3 parts of boric acid, and 700 parts of water evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0029] Example 2

[0030] A1. Magnesium oxide, benzyl dimethylamine, and glycidol were added to N,N-dimethylformamide and mixed (the ratio of magnesium oxide, benzyl dimethylamine, glycidol, and N,N-dimethylformamide was 1g:0.03g:2mL:20mL). The mixture was stirred at 700rpm and reacted at 120℃ for 4h. After filtration, the solid was washed with ethanol and dried to obtain glycidol-modified magnesium oxide.

[0031] A2. Mix 200 parts of glycidol-modified magnesium oxide, 5 parts of titanium dioxide, 2.5 parts of boric acid, and 1600 parts of water evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0032] Example 3

[0033] A1. Magnesium oxide, benzyl dimethylamine, and glycidol were added to N,N-dimethylformamide and mixed (the ratio of magnesium oxide, benzyl dimethylamine, glycidol and N,N-dimethylformamide was 1g:0.05g:2mL:25mL). The mixture was stirred at 600rpm and reacted at 125℃ for 3h. After filtration, the solid was washed with ethanol and dried to obtain glycidol-modified magnesium oxide.

[0034] A2. Mix 240 parts of glycidol-modified magnesium oxide, 5 parts of titanium dioxide, 2.5 parts of boric acid, and 2400 parts of water evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0035] Example 4

[0036] A1. Magnesium oxide, benzyl dimethylamine, and glycidol were added to N,N-dimethylformamide and mixed (the ratio of magnesium oxide, benzyl dimethylamine, glycidol, and N,N-dimethylformamide was 1g:0.02g:2.5mL:25mL). The mixture was stirred at 500rpm and reacted at 130℃ for 2h. After filtration, the solid was washed with ethanol and dried to obtain glycidol-modified magnesium oxide.

[0037] A2. Mix 40 parts of glycidol-modified magnesium oxide, 2 parts of titanium dioxide, 1 part of boric acid, and 320 parts of water evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0038] Example 5

[0039] A1. Magnesium oxide, benzyl dimethylamine, and glycidol were added to N,N-dimethylformamide and mixed (the ratio of magnesium oxide, benzyl dimethylamine, glycidol, and N,N-dimethylformamide was 1g:0.03g:2mL:20mL). The mixture was stirred at 700rpm and reacted at 120℃ for 4h. After filtration, the solid was washed with ethanol and dried to obtain glycidol-modified magnesium oxide.

[0040] A2. Mix 200 parts of glycidol-modified magnesium oxide, 5 parts of titanium dioxide, 2.5 parts of boric acid, 0.5 parts of sodium polyacrylate, and 1600 parts of water evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0041] Example 6

[0042] The only difference from Example 5 is that 1.5 parts of sodium polyacrylate were used.

[0043] Example 7

[0044] The only difference from Example 5 is that it contains 3 parts sodium polyacrylate.

[0045] Example 8

[0046] The only difference from Example 5 is that it contains 5 parts of sodium polyacrylate.

[0047] Comparative Example 1

[0048] 200 parts of magnesium oxide, 5 parts of titanium dioxide, 2.5 parts of boric acid, and 1600 parts of water were mixed evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0049] Comparative Example 2

[0050] 200 parts of magnesium oxide, 5 parts of titanium dioxide, 2.5 parts of boric acid, 1.5 parts of sodium polyacrylate, and 1600 parts of water were mixed evenly to obtain a magnesium oxide annealing release agent for oriented silicon steel.

[0051] The magnesium oxide annealing release agent for oriented silicon steel obtained in Examples 1-8 and Comparative Examples 1-2 was used at a concentration of 10 g / m 2 The coating amount was applied to the surface of decarburized annealed grain-oriented silicon steel (the grain-oriented silicon steel is composed of the following components by weight percentage: C 0.007%, Si 3.5%, Mn 0.006%, Al 0.03%, N 0.0075%, with the remainder being Fe and unavoidable impurities), dried, and then annealed at 800℃ for 1 min. The following performance tests were then performed:

[0052] (1) Magnetic induction intensity: The magnetic induction intensity under an 800 A / m magnetic field was measured in accordance with GB / T 13789-2022 "Method for measuring the magnetic properties of electrical steel strips (sheets) using a single-piece tester";

[0053] (2) Iron loss: The iron loss under a 50Hz alternating magnetic field with a magnetic induction intensity of 1.7T was measured in accordance with GB / T 13789-2022 "Method for measuring the magnetic properties of electrical steel strips (sheets) using a single-piece tester";

[0054] The test results are recorded in Table 1.

[0055] Table 1. Performance test results of magnesium oxide annealing release agent for grain-oriented silicon steel.

[0056]

[0057] As can be seen from Table 1, the magnetic induction intensity of the magnesium oxide annealing release agent for oriented silicon steel obtained by applying Examples 1-8 is higher than that of Comparative Examples 1-2, and the iron loss is lower than that of Comparative Examples 1-2. This indicates that after magnesium oxide is modified with glycidol, the magnetic properties of oriented silicon steel are improved and the iron loss is reduced.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnesium oxide annealing release agent for grain-oriented silicon steel, characterized in that, The composition comprises the following components in parts by weight: 40-240 parts of glycidol-modified magnesium oxide, 2-6 parts of titanium dioxide, 1-3 parts of boric acid, 320-2400 parts of water, and 0.5-5 parts of sodium polyacrylate; the raw materials for the glycidol-modified magnesium oxide include magnesium oxide and glycidol in a mass-to-volume ratio of 1g:1.5-2.5mL; the preparation method of the glycidol-modified magnesium oxide includes the following steps: mixing magnesium oxide, catalyst, glycidol and solvent, modifying, filtering and collecting the solid, washing, and drying to obtain glycidol-modified magnesium oxide; the catalyst is a tertiary amine; the mass ratio of magnesium oxide to catalyst is 1:0.01-0.05, and the mass-to-volume ratio of magnesium oxide to solvent is 1g:15-25mL; the modification temperature is 110-130℃, and the modification time is 2-5h.

2. The magnesium oxide annealing release agent for oriented silicon steel according to claim 1, characterized in that, The washing process specifically involves washing with ethanol.

3. The magnesium oxide annealing release agent for oriented silicon steel according to claim 1, characterized in that, The mass ratio of the glycidol-modified magnesium oxide to the sodium polyacrylate is 200:1.5~3.

4. A method for preparing an annealing release agent for oriented silicon steel magnesium oxide, used to prepare the annealing release agent for oriented silicon steel magnesium oxide as described in any one of claims 1 to 3, characterized in that, Includes the following steps: The raw materials are mixed evenly to obtain magnesium oxide annealing release agent for oriented silicon steel.

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