Preparation method, product and application of calcium-aluminum-based casting powder

Abstract

The invention relates to the technical field of casting powder, in particular to a preparation method, a product and application of calcium-aluminum-based casting powder. The preparation method of the calcium-aluminum-based casting powder comprises the following steps that limestone, bauxite, silica, dolomite and an accelerant are mixed to be uniform, and a mixed material is obtained; carrying out compression molding on the mixed material to obtain a block material; and after roasting the block material, crushing and grinding, and mixing with an adhesive and a carbon material to make slurry and granulate to obtain the calcium-aluminum-based casting powder. Through solid roasting, component volatilization is effectively reduced, energy consumption is reduced, and reactivity and uniformity of the casting powder are improved. Compared with a traditional pre-melting process, the prepared casting powder has higher stability and adaptability, is more suitable for being used in a continuous casting process and has remarkable economic and application advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of mold fluxes, and particularly to a preparation method, product and application of a calcium-aluminum-based mold flux. Background Art

[0002] Calcium-aluminum-based mold fluxes are widely used in the continuous casting process. Their main function is to provide effective heat insulation protection for the molten steel, reduce heat loss, optimize the fluidity and wettability of the molten steel in the mold, thereby preventing inclusions from entering the billet and improving the surface quality of the billet. Their main chemical components include CaO, Al2O3, SiO2, MgO and a small amount of alkali metal oxides. By reasonably adjusting the melting point, fluidity and wettability of the molten slag through proper proportioning, an ideal continuous casting effect can be achieved. However, in the actual production process, calcium-aluminum-based mold fluxes face problems such as difficult control of solid-phase reactions and loss of volatile components at high temperatures. These problems limit the use efficiency of the mold flux, resulting in unstable protection effect for the molten steel and even affecting the product quality. Therefore, there is an urgent need for an innovative process method to optimize the performance of the mold flux and improve its utilization efficiency and effect in the continuous casting process.

[0003] Traditional preparation processes for pre-melted mold fluxes usually achieve component homogenization and pretreatment through high-temperature melting. However, this process has high energy consumption and high production costs. At the same time, high-temperature melting also causes components to be easily volatilized at high temperatures, affecting the compositional uniformity and stability of the mold flux. To overcome these problems, the solid-state roasting process has gradually attracted attention as an alternative technology. Solid-state roasting can not only effectively reduce energy consumption but also reduce component volatilization, ensuring the uniformity and stability of the material. Currently, there have been many studies and patents on the technology of solid-state roasted mold fluxes. For example, Patent CN115069992B proposes a continuous casting production method based on preheating of solid-state mold fluxes. Before the solid-state mold flux is put into the continuous casting mold, it is preheated to a high-temperature solid state so that the mold flux carries sufficient heat to maintain continuous and stable continuous casting production. Although many technologies have explored the treatment of solid-state pre-melted mold fluxes, their processes still face problems such as complex operation, relatively high energy consumption, and difficulty in achieving continuous production. Therefore, the solid-state roasting mold flux process still faces challenges in terms of operation difficulty and practical industrial application. Summary of the Invention

[0004] Based on the above, the present invention provides a preparation method, product and application of a calcium-aluminum-based mold flux. The present invention effectively solves the problems of high energy consumption and high cost of traditional pre-melted mold fluxes by introducing a briquetting solid-state roasting process. Compared with traditional pre-melted mold fluxes, the method of the present invention not only reduces energy consumption but also improves the performance stability of the mold flux and the operability of industrial application, significantly enhancing its application value in actual production.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is a method for preparing a calcium-aluminum-based protective slag, comprising the following steps:

[0007] Mixing limestone, bauxite, silica, dolomite and an accelerator to obtain a mixed material;

[0008] Pressing the mixed material into a shape to obtain a block material;

[0009] The block material is calcined, crushed and ground, mixed with a binder and a carbonaceous material to make pulp and granulate, and the calcium-aluminum-based protective slag is obtained.

[0010] The second technical solution of the present invention is a calcium-aluminum-based protective slag prepared according to the above-mentioned preparation method.

[0011] The third technical solution of the present invention is the application of the above-mentioned calcium-aluminum-based protective slag in the continuous casting of high-aluminum steel.

[0012] The present invention discloses the following technical effects:

[0013] The present invention effectively solves the problems of high energy consumption, component volatilization, and high production cost in the high-temperature melting pretreatment process in the prior art by introducing a solid-state roasting process. The solid-state roasting method adopted by the present invention includes mixing the protective slag raw material with the promoter and pressing it into a block material, followed by solid-state roasting, crushing and grinding the material after the roasting treatment, and finally granulating it into a shape. Through this method, the reactivity and uniformity of the protective slag can be significantly improved, while reducing the high-temperature volatilization phenomenon (the volatilization rate under 1600°C can be reduced by 0.4%-0.1%, and the volatilization rate under 1300°C can be reduced by 0.6%-1.5%), reducing production energy consumption and costs. Compared with the traditional pre-melting protective slag preparation method, this method can improve the stability and application effect of the protective slag, making it more suitable for the actual needs in the continuous casting process. DETAILED DESCRIPTION

[0014] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0015] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0016] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0017] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of this invention are obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0018] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0019] The "%" mentioned in this invention, unless otherwise specified, all represent mass percentages.

[0020] The first aspect of this invention provides a preparation method of a calcium-aluminum-based mold powder, comprising the following steps:

[0021] Mix limestone, bauxite, silica, dolomite and a promoter evenly to obtain a mixed material;

[0022] Press the said mixed material into a formed body to obtain a block material;

[0023] Roast the block material, then crush and grind it, and mix it with an adhesive and a carbonaceous material to make a slurry and granulate it to obtain the calcium-aluminum-based mold powder.

[0024] In a preferred embodiment of this invention, the mass ratio of the limestone to the bauxite, silica and dolomite is (45 - 50):(30 - 38):(3 - 8):(1 - 4).

[0025] In a preferred embodiment of this invention, the promoter is calcium chloride, and the content of the promoter in the mixed material is 0.3wt% - 3wt%; the average particle size of the promoter is 0.10 - 0.15mm.

[0026] In this invention, the role of the promoter is to promote solid-state roasting, thereby reducing the phenomenon of high-temperature volatilization, and reducing production energy consumption and costs.

[0027] In a preferred embodiment of this invention, the pressure for pressing into a formed body is 22MPa - 30MPa, and the pressure stabilization time is 35s - 60s.

[0028] In a preferred embodiment of the present invention, the particle size of the bulk material is 3 mm - 5 mm; the shape of the block material is any one of a cuboid, a sphere, and an ellipsoid.

[0029] In a preferred embodiment of the present invention, the roasting is specifically heating to 900 °C - 1080 °C at a rate of 8 °C / min - 20 °C / min and holding for 20 min - 50 min; the crushing and grinding is specifically crushing and grinding to a particle size of 0.02 - 0.05 mm.

[0030] In a preferred embodiment of the present invention, the binder is one or more of glass, carboxymethyl cellulose, and bentonite; the addition amount of the binder is 0.3% - 2% of the mass of the mixed material; the carbonaceous material includes carbon black and graphite; the mass ratio of carbon black to graphite is (1 - 4):1; the addition amount of the carbonaceous material is 2% - 10% of the mass of the mixed material.

[0031] In the present invention, no special limitation is imposed on the method of making pulp and granulating, and the method of making pulp and granulating well-known to those skilled in the art can be adopted.

[0032] The second aspect of the present invention provides a calcium-aluminum-based mold powder prepared by the above preparation method.

[0033] The third aspect of the present invention provides the application of the above calcium-aluminum-based mold powder in the continuous casting of high-aluminum steel.

[0034] The present invention effectively reduces component volatilization through solid-state roasting, reduces energy consumption, and improves the reactivity and uniformity of the mold powder. Compared with the traditional pre-melting process, the prepared mold powder has higher stability and adaptability, is more suitable for use in the continuous casting process, and has significant economic and application advantages.

[0035] The technical solutions of the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are all purchased from commercial channels or have been made public.

[0036] By mass percentage, the main component composition of the limestone used in the examples of the present invention is CaCO3: 92.0% - 95.0%, MgCO3: 1.0% - 2.0%, and Al2O3: 0.3% - 1.0%; the particle size range is 0.10 mm - 0.30 mm.

[0037] By mass percentage, the main component composition of the bauxite used in the examples of the present invention is Al2O3: 86% - 90%, SiO2: 2.0% - 4%, Fe2O3: 0% - 1.5%, TiO2: 0.5% - 1.5%, and CaO: 0.5% - 1.0%; the particle size range is 0.10 mm - 0.30 mm.

[0038] By mass percentage, the main component composition of the silica used in the embodiments of the present invention is SiO2: 97.0% - 99.0%, Al2O3: 0.2% - 0.4%, and CaO: 0.2% - 0.4%; the particle size range is 0.10 mm to 0.30 mm.

[0039] By mass percentage, the main component composition of the dolomite used in the embodiments of the present invention is CaCO3: 50.0% - 56%, MgCO3: 40.0% - 42%, and SiO2: 0.0% - 1.0%; the particle size range is 0.10 mm to 0.30 mm.

[0040] The average particle size of the carbon black used in the embodiments of the present invention is 0.08 mm; the average particle size of the graphite used is 0.02 mm; the average particle size of the calcium chloride used in the embodiments of the present invention is 0.11 mm.

[0041] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0042] Example 1

[0043] The present invention provides a preparation method of a calcium-aluminum-based mold powder (block solid roasting process), and the steps are as follows:

[0044] Mix limestone, bauxite, silica, dolomite and calcium chloride in proportion to obtain a mixed material. Among them, the addition amount of calcium chloride is 0.59% of the total mass of the mixed material; the mass ratio of limestone: bauxite: silica: dolomite is 45:35:6:2. Perform a pressing operation on the mixed material, set the pressing pressure to 26.99 MPa, and the pressure stabilizing time to 45 seconds. The particle size of the pressed cuboid-shaped material is 3 - 5 mm. Subsequently, roast the pressed block-shaped material, with a heating rate of 12 °C / min. After the roasting temperature reaches 960 °C, keep it warm for 30 minutes to ensure the full reaction of the material. After roasting, crush and grind the solid-roasted material to a particle size of 0.02 - 0.05 mm, and add bentonite accounting for 0.55% of the mass of the mixed material and 4.33% of the carbonaceous material. The carbonaceous material is obtained by mixing carbon black and graphite in a weight ratio of 3:1. Finally, make a slurry of these mixed materials and granulate to obtain the final calcium-aluminum-based mold powder.

[0045] The calcium-aluminum-based mold powder prepared in this example has a good melting state on the surface of the molten steel, no large slag strips are generated, the liquid slag flows smoothly into the channel, and shows a good covering effect. The main component composition of this calcium-aluminum-based mold powder is: CaO = 42.55%, Al2O3 = 31.44%, SiO2 = 7.12%, and MgO = 1.24%; the melting temperature is 1421.33 °C.

[0046] Example 2

[0047] The present invention provides a preparation method of a calcium-aluminum-based mold powder (pressing and solid-state roasting process), and the steps are as follows:

[0048] Mix limestone, bauxite, silica, dolomite and calcium chloride in proportion to obtain a mixed material. Among them, the addition amount of calcium chloride is 1.50% of the total mass of the mixed material; the mass ratio of limestone: bauxite: silica: dolomite is 46:38:8:3. Perform a pressing operation on the mixed material, set the pressing pressure to 25.00 MPa, the pressure stabilization time to 45 seconds, and the particle size of the pressed cuboid-shaped material to 3-5 mm. Subsequently, roast the pressed block-shaped material, with a heating rate of 12 °C / min. After the roasting temperature reaches 1000 °C, keep it warm for 30 minutes to ensure the full reaction of the material. After roasting, crush and grind the solid-state roasted material to a particle size of 0.02-0.05 mm, and add bentonite accounting for 0.85% of the mass of the mixed material and carbonaceous material accounting for 3.25%. The carbonaceous material is obtained by mixing carbon black and graphite in a weight ratio of 3:1. Finally, granulate these mixed materials into slurry to obtain the final calcium-aluminum-based mold powder.

[0049] The calcium-aluminum-based mold powder prepared in this example has a good melting state on the molten steel surface, no large slag bars are generated, the liquid slag flows smoothly into the channel, and shows a good covering effect. The main component composition of this calcium-aluminum-based mold powder is: CaO = 43.28%, Al2O3 = 32.14%, SiO2 = 7.08%, and MgO = 1.21%; the complete melting temperature is 1419.58 °C.

[0050] Example 3

[0051] The present invention provides a preparation method of a calcium-aluminum-based mold powder (pressing and solid-state roasting process), and the steps are as follows:

[0052] Mix limestone, bauxite, silica, dolomite and calcium chloride in proportion to obtain a mixed material. Among them, the addition amount of calcium chloride is 1.83% of the total mass of the mixed material; the mass ratio of limestone: bauxite: silica: dolomite is 50:36:8:4. Perform briquetting on the mixed material, set the briquetting pressure at 28.00 MPa, and the pressure stabilization time at 45 seconds. The size of the pressed cuboid briquette is 3 - 5 mm. Subsequently, roast the pressed briquette, with a heating rate of 12 °C / min. After the roasting temperature reaches 1030 °C, keep it warm for 35 minutes to ensure the full reaction of the material. After roasting, crush and grind the solid roasted material to a particle size of 0.02 - 0.05 mm, and add bentonite accounting for 0.90% of the mass of the mixed material and 6.50% of the carbonaceous material. The carbonaceous material is obtained by mixing carbon black and graphite in a weight ratio of 4:1. Finally, make a slurry and granulate these mixed materials to obtain the final calcium-aluminum-based mold powder.

[0053] The calcium-aluminum-based mold powder prepared in this example has a good melting state on the molten steel surface, no large slag bars are generated, and the liquid slag flows smoothly into the channel, showing a good covering effect. The main component composition of this calcium-aluminum-based mold powder is: CaO = 46.71%, Al2O3 = 33.14%, SiO2 = 6.57%, and MgO = 1.01%; the complete melting temperature is 1423.41 °C.

[0054] Comparative Example 1

[0055] The difference from Example 3 is only that the addition of calcium chloride is omitted, and the remaining steps and parameters are the same as those in Example 3.

[0056] The calcium-aluminum-based mold powder prepared in this comparative example has a good melting state on the molten steel surface. The composition of the calcium-aluminum-based mold powder prepared in this comparative example is CaO = 47.58%, Al2O3 = 33.76%, SiO2 = 6.69%, MgO = 1.03%, and the complete melting temperature is 1424.07 °C.

[0057] Comparative Example 2

[0058] The difference from Example 3 is only that the addition amount of the carbonaceous material is 1.50% of the mass of the mixed material, and the remaining steps and parameters are the same as those in Example 3.

[0059] The calcium-aluminum-based mold powder prepared in this comparative example has a poor melting state and covering effect on the molten steel surface. The composition of the calcium-aluminum-based mold powder prepared in this comparative example is CaO = 47.42%, Al2O3 = 33.64%, SiO2 = 6.67%, MgO = 1.03%, and the complete melting temperature is 1430.23 °C.

[0060] Comparative Example 3

[0061] The difference from Example 3 is only that the addition amount of the carbonaceous material is 0.50% of the mass of the mixed materials, and the remaining steps and parameters are the same as those in Example 3.

[0062] The molten state and covering effect of the calcium-aluminum-based mold flux prepared in this comparative example on the molten steel surface are poor. The composition of the calcium-aluminum-based mold flux prepared in this comparative example is CaO = 46.94%, Al2O3 = 33.31%, SiO2 = 6.60%, MgO = 1.03%, and the complete melting temperature is 1434.42 °C.

[0063] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A preparation method of a calcium-aluminum-based mold powder, characterized in that, The following steps are involved: Mixing limestone, bauxite, silica, dolomite and an accelerator to obtain a mixed material; Pressing the mixed material into a shape to obtain a block material; The block material is calcined, crushed and ground, mixed with a binder and a carbonaceous material to make pulp and granulate, and the calcium-aluminum-based protective slag is obtained.

2. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that, The mass ratio of the limestone to the bauxite, silica and dolomite is (45-50):(30-38):(3-8):(1-4).

3. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that, The accelerator is calcium chloride, and the content of the accelerator in the mixed material is 0.3wt%-3wt%; the average particle size of the accelerator is 0.10-0.15mm.

4. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that, The pressure of the pressing molding is 22MPa-30MPa, and the pressure stabilization time is 35s-60s.

5. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that, The particle size of the block material is 3mm-5mm; the shape of the block material is a cuboid, a sphere or an ellipsoid.

6. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that The roasting is specifically to increase the temperature to 900°C-1080°C at a rate of 8°C / min-20°C / min and keep the temperature for 20min-50min; the crushing and grinding is specifically to crush and grind to a particle size of 0.02-0.05mm.

7. The preparation method of the calcium-aluminum-based mold powder according to claim 1, characterized in that The binder is one or more of glass, carboxymethyl cellulose, and bentonite; the amount of the binder added is 0.3%-2% of the mass of the mixture; the carbonaceous material includes carbon black and graphite; the mass ratio of the carbon black to the graphite is (1-4):1; the amount of the carbonaceous material added is 2%-10% of the mass of the mixture.

8. The calcium-aluminum-based protective slag prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the calcium-aluminum-based protective slag as claimed in claim 8 in high-aluminum steel continuous casting.