Method for preparing tundish permanent lining from high-silica magnesite tailings

Abstract

The application discloses a method for preparing a tundish permanent lining from high-silicon magnesite tailings, and the tundish permanent lining is prepared from high-silicon magnesite tailings, light-burned magnesium powder and silica sol as main raw materials through pretreatment, screening, mixing and heat preservation treatment. The tundish permanent lining is prepared by taking the high-silicon magnesite tailings as the main raw material through a simple preparation process with low energy consumption and low cost, and the effective chemical components of the high-silicon magnesite tailings are fully utilized, so that the tundish permanent lining with good erosion resistance and heat preservation effect is prepared, the resource recycling is realized, the manufacturing cost is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of magnesite tailings recycling technology, specifically a method for preparing a permanent liner for an intermediate ladle from high-silicon magnesite tailings. Background Technology

[0002] The tundish in continuous casting is an essential vessel in short-process steelmaking. Molten steel poured from the ladle is distributed to various crystallizers through the tundish nozzle. Due to frequent impacts from the molten steel during use, especially on the permanent lining, the service life of the permanent lining directly affects the overall service life of the tundish. Currently, tundish permanent linings mostly use heavy castables, which have high density and thermal conductivity, resulting in poor heat insulation. If the molten steel casting temperature in the tundish is too low, the viscosity of the molten steel increases, making it difficult for inclusions to float and resulting in poor billet surface quality. Therefore, it is necessary to increase the molten steel temperature to maintain the tundish temperature, thus increasing steelmaking costs.

[0003] Therefore, by fully utilizing the effective components in high-silica magnesite tailings, optimizing the preparation process of the permanent lining of the tundish, reducing the cooling during the tundish casting process and obtaining a more stable temperature fluctuation, it is possible to achieve resource recycling, ensure good insulation effect of the tundish, and achieve long service life and low-cost operation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a permanent liner for an intermediate bag from high-silica magnesite tailings, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a permanent liner for an tundish from high-silica magnesite tailings, using high-silica magnesite tailings, lightly calcined magnesia powder, and silica sol as main raw materials. After raw material pretreatment, screening, mixing, and heat preservation treatment, a permanent liner for the tundish is obtained. The specific steps are as follows:

[0006] Step 1: Raw material pretreatment: The high-silicon magnesite tailings are crushed into large particles using a jaw crusher; the large particles are further crushed into small particles with a particle size of 0.2-2mm using a roller crusher.

[0007] Step 2, Screening: The crushed high-silica magnesite tailings from Step 1 are screened into three specifications: particles with a diameter of 3-5mm, particles with a diameter of 1-3mm, and micro powder with a diameter of 0.088mm.

[0008] Step 3: Mixing: Weigh the following raw materials by weight percentage: 15-25 parts of tailings particles with a diameter of 3-5mm, 30-45 parts of tailings particles with a diameter of 1-3mm, 25-40 parts of tailings powder with a diameter <1mm, and 5-10 parts of lightly calcined magnesium powder. Mix them thoroughly in a mixer, then add 3-5% of the total amount of the above mixture with silica sol, stir evenly, and vibrate to form the final product.

[0009] Step 4, heat preservation: The cured mixture obtained in Step 3 is kept at 90-110℃ for 12-24 hours to obtain the permanent lining of the tundish.

[0010] Preferably, the MgO content of the lightly calcined magnesium powder is ≥82%, and the SiO2 content of the silicon micropowder is ≥92%.

[0011] Preferably, the curing process in step three is carried out at room temperature for 12-24 hours.

[0012] Preferably, in step one, a portion of the small particles are selected and finely ground into micro powder with a particle size of 0.088 mm using a ball mill.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The tundish permanent lining of the present invention has a simple preparation process, uses high-silicon magnesite tailings as the main raw material with low energy consumption and low cost, and makes full use of the effective chemical components of high-silicon magnesite tailings to prepare a tundish permanent lining with good erosion resistance and heat preservation effect, realizes resource recycling, reduces production costs and extends service life. Detailed Implementation

[0015] 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.

[0016] To achieve the above objectives, the present invention provides the following technical solution:

[0017] Example 1:

[0018] A method for preparing a permanent liner for an tundish using high-silica magnesite tailings, using high-silica magnesite tailings, lightly calcined magnesia powder, and silica sol as main raw materials, involves raw material pretreatment, screening, mixing, and heat preservation treatment to obtain the permanent liner for the tundish. The specific steps are as follows:

[0019] Step 1: Raw material pretreatment: The high-silicon magnesite tailings are crushed into large particles using a jaw crusher; the large particles are further crushed into small particles with a particle size of 0.2-2mm using a roller crusher; some of the small particles are then finely ground into micro powder with a particle size of 0.088mm using a ball mill.

[0020] Step 2, Screening: The crushed high-silica magnesite tailings from Step 1 are screened into three specifications: particles with a diameter of 3-5mm, particles with a diameter of 1-3mm, and micro powder with a diameter of 0.088mm.

[0021] Step 3: Mixing: Weigh the following raw materials by weight percentage: 20 parts of tailings particles with a diameter of 3-5mm, 40 parts of tailings particles with a diameter of 1-3mm, 35 parts of tailings powder with a diameter <1mm, and 5 parts of lightly calcined magnesia powder. Mix them thoroughly in a mixer, then add 4% of the total amount of the above mixture with silica sol, stir evenly, vibrate to form, and cure at room temperature for 24 hours.

[0022] Step 4, heat preservation: The cured mixture obtained in Step 3 is kept at 110℃ for 24 hours to obtain the permanent lining of the tundish.

[0023] The MgO content of lightly calcined magnesium powder is ≥82%, and the SiO2 content of silicon micropowder is ≥92%.

[0024] The permanent liner of the intermediate ladle prepared in this embodiment was found to have a bulk density of 3.20 g / cm³ after firing at 1500°C for 3 hours. 3 It has a compressive strength of 80MPa and retains 95% of its residual strength after a single thermal shock test with water cooling at 1300℃.

[0025] Implementation: 2:

[0026] A method for preparing a permanent liner for an tundish using high-silica magnesite tailings, using high-silica magnesite tailings, lightly calcined magnesia powder, and silica sol as main raw materials, involves raw material pretreatment, screening, mixing, and heat preservation treatment to obtain the permanent liner for the tundish. The specific steps are as follows:

[0027] Step 1: Raw material pretreatment: The high-silicon magnesite tailings are crushed into large particles using a jaw crusher; the large particles are further crushed into small particles with a particle size of 0.2-2mm using a roller crusher; some of the small particles are then finely ground into micro powder with a particle size of 0.088mm using a ball mill.

[0028] Step 2, Screening: The crushed high-silica magnesite tailings from Step 1 are screened into three specifications: particles with a diameter of 3-5mm, particles with a diameter of 1-3mm, and micro powder with a diameter of 0.088mm.

[0029] Step 3: Mixing: Weigh the following raw materials by weight percentage: 25 parts of tailings particles with a diameter of 3-5mm, 40 parts of tailings particles with a diameter of 1-3mm, 25 parts of tailings powder with a diameter <1mm, and 10 parts of lightly calcined magnesia powder. Mix them thoroughly in a mixer, then add 5% of the total amount of the above mixture with silica sol, stir evenly, vibrate to form, and cure at room temperature for 16 hours.

[0030] Step 4, heat preservation: The cured mixture obtained in Step 3 is kept at 110℃ for 24 hours to obtain the permanent lining of the tundish.

[0031] The MgO content of lightly calcined magnesium powder is ≥82%, and the SiO2 content of silicon micropowder is ≥92%.

[0032] The permanent liner of the intermediate ladle prepared in this embodiment, after being kept at 1350℃ for 3 hours, had a bulk density of 3.22 g / cm³. 3 The compressive strength is 85MPa. After five thermal shock tests with water cooling at 1100℃, the residual room temperature compressive strength of the product is 75%.

[0033] Implementation: 3:

[0034] A method for preparing a permanent liner for an tundish using high-silica magnesite tailings, using high-silica magnesite tailings, lightly calcined magnesia powder, and silica sol as main raw materials, involves raw material pretreatment, screening, mixing, and heat preservation treatment to obtain the permanent liner for the tundish. The specific steps are as follows:

[0035] Step 1: Raw material pretreatment: The high-silicon magnesite tailings are crushed into large particles using a jaw crusher; the large particles are further crushed into small particles with a particle size of 0.2-2mm using a roller crusher; some of the small particles are then finely ground into micro powder with a particle size of 0.088mm using a ball mill.

[0036] Step 2, Screening: The crushed high-silica magnesite tailings from Step 1 are screened into three specifications: particles with a diameter of 3-5mm, particles with a diameter of 1-3mm, and micro powder with a diameter of 0.088mm.

[0037] Step 3: Mixing: Weigh the following raw materials by weight percentage: 20 parts of tailings particles with a diameter of 3-5mm, 40 parts of tailings particles with a diameter of 1-3mm, 30 parts of tailings powder with a diameter <1mm, and 10 parts of lightly calcined magnesia powder. Mix them thoroughly in a mixer, then add 5% of the total amount of the above mixture with silica sol, stir evenly, vibrate to form, and cure at room temperature for 24 hours.

[0038] Step 4, heat preservation: The cured mixture obtained in Step 3 is kept at 110℃ for 12 hours to obtain the permanent lining of the tundish.

[0039] The MgO content of lightly calcined magnesium powder is ≥82%, and the SiO2 content of silicon micropowder is ≥92%.

[0040] The permanent liner of the intermediate ladle prepared in this embodiment was tested and found to have a bulk density of 3.23 g / cm³ after firing at 1500°C for 3 hours. 3 The compressive strength is 88MPa, and the residual strength remains at 96% after a single thermal shock test with water cooling at 1300℃.

[0041] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a permanent liner for an intermediate bag from high-silica magnesite tailings, characterized in that: Using high-silica magnesite tailings, lightly calcined magnesia powder, and silica sol as main raw materials, a permanent lining for an tundish is prepared after raw material pretreatment, screening, mixing, and heat preservation. The specific steps are as follows: Step 1: Raw material pretreatment: The high-silicon magnesite tailings are crushed into large particles using a jaw crusher; the large particles are further crushed into small particles with a particle size of 0.2-2mm using a roller crusher. In step one, select a portion of the small particles and grind them into micro powder with a particle size of 0.088 mm using a ball mill; Step 2, Screening: The crushed high-silica magnesite tailings from Step 1 are screened into three specifications: particles with a diameter of 3-5mm, particles with a diameter of 1-3mm, and micro powder with a diameter of 0.088mm. Step 3: Mixing: Weigh the following raw materials by weight percentage: 15-25 parts of tailings particles with a diameter of 3-5mm, 30-45 parts of tailings particles with a diameter of 1-3mm, 25-40 parts of tailings powder with a diameter <1mm, and 5-10 parts of lightly calcined magnesium powder. Mix them thoroughly in a mixer, then add 3-5% of the total amount of the above mixture with silica sol, stir evenly, and vibrate to form the final product. Step 4, heat preservation: The cured mixture obtained in Step 3 is kept at 90-110℃ for 12-24 hours to obtain the permanent lining of the tundish.

2. The method for preparing a permanent liner for an intermediate bag from high-silica magnesite tailings according to claim 1, characterized in that: The lightly calcined magnesium powder has an MgO content of ≥82%, and the silica sol has an SiO2 content of ≥92%.

3. The method for preparing a permanent liner for an intermediate bag from high-silica magnesite tailings according to claim 1, characterized in that: In step three, cure at room temperature for 12-24 hours.