Breathable seating brick repair material for steel ladle and preparation method of permeable seating brick repair material

Abstract

The invention relates to the technical field of steelmaking steel ladle refractory materials, and discloses a steel ladle breathable seating brick repairing material and a preparation method thereof, the steel ladle breathable seating brick repairing material comprises the following raw materials by weight: 70-90% of sintered corundum particles and fine powder, 1-5% of active magnesium oxide powder, 5-15% of active alpha aluminum oxide micro powder, 5-10% of sodium metasilicate, and 1-5% of paraffin powder. Sodium metasilicate and paraffin powder are introduced, sodium metasilicate is decomposed at the temperature of 300 DEG C or above to discharge a large amount of water and water vapor, paraffin is melted to drive the repairing material to flow and fill gaps, sodium metasilicate is used for replacing cement to achieve a bonding effect, and sodium salt formed after sodium metasilicate is decomposed plays a role of a bonding agent; the strength of the repairing material is high after the repairing material is decomposed and dried, the anti-scouring capability is high, the air brick core is effectively protected, and the service life of the air brick core is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory materials for steel ladles in steelmaking, and particularly relates to a repairing material for a breathable seat brick for a steel ladle and a preparation method thereof. Background Art

[0002] The breathable brick of the steel ladle is the most critical functional refractory material in the bottom blowing argon process. The service conditions are relatively harsh, and high requirements are imposed on the blow-through rate and service life of the product, especially for the smelting of varieties. In order to meet the requirements of different smelting conditions, the breathable bricks are divided into two categories according to the structure: the built-in breathable brick and the external breathable brick. For the external breathable brick, it is necessary to first remove the breathable brick core that has reached the service life under the condition that the temperature of the steel ladle reaches about 800 °C, then install a new breathable brick core, and finally repair the gap between the breathable brick core and the breathable seat brick. At present, the method for repairing the gap is as follows: adding water and stirring manually or by a mixer until the repairing material is evenly mixed and has very good self-flowability, then packaging it with a plastic bag and throwing it into the small head part of the breathable brick core (i.e., the working end of the breathable brick core and the breathable seat brick). After the plastic bag is quickly melted by high temperature, the repairing material freely flows to fill the gap between the breathable brick core and the breathable seat brick.

[0003] However, when the traditional repairing material is constructed, it is necessary to add water or other binders and mix and stir on site. If manually stirred, it is time-consuming and laborious, and the mixing effect is poor; if mechanically stirred, professional equipment and space are required. If the site is narrow, it will cause inconvenient mixing and uneven mixing, which is uneconomical and time-consuming, seriously affecting the repairing effect and even the operation efficiency of the steel ladle.

[0004] Therefore, in order to improve the convenience of construction and the repairing effect, the applicant has proposed a repairing material for a breathable seat brick for a steel ladle and a preparation method thereof. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a repairing material for a breathable seat brick for a steel ladle and a preparation method thereof.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A repairing material for a breathable seat brick for a steel ladle, the raw material composition includes: by weight percentage, 70-90% of sintered corundum particles and fine powder, 1-5% of active magnesium oxide powder, 5-15% of active α-aluminum trioxide fine powder, 5-10% of sodium metasilicate, and 1-5% of paraffin powder.

[0008] Further, the sintered corundum particles and fine powder include sintered corundum particles with a particle size of 1-6 mm and sintered corundum fine powder with a particle size <0.15 mm, 50-60% of the sintered corundum particles, and 20-30% of the sintered corundum fine powder.

[0009] Further, the particle size of the activated magnesium oxide powder is < 0.045 mm.

[0010] Further, the particle size of the activated α-aluminum oxide fine powder is < 0.005 mm.

[0011] Further, the particle size of the sodium metasilicate is < 1 mm.

[0012] Further, the sodium metasilicate is sodium metasilicate nonahydrate.

[0013] Further, the particle size of the paraffin powder is < 0.074 mm.

[0014] Further, its chemical composition is: by weight percentage, Al 2 O 3 +MgO ≥ 80%.

[0015] Further, the apparent porosity of the repair material is ≤ 35%, the normal temperature compressive strength at 110°C * 24 h ≥ 30 MPa, the normal temperature compressive strength at 1500°C * 3 h ≥ 80 MPa, the normal temperature flexural strength at 110°C * 24 h ≥ 5 MPa, the normal temperature flexural strength at 1500°C * 3 h ≥ 18 MPa, and the bulk density ≥ 2.4 g / cm 3 .

[0016] Based on the above-mentioned preparation method of the breathable seat brick repair material for ladles, it includes the following steps:

[0017] S1. Weigh each raw material according to the weight ratio. After checking and weighing correctly, add them into a mixer for stirring and mixing. Add the particles first and then the fine powder in the feeding order. After adding all the materials, mix for 3 - 5 minutes. Wait until the materials are evenly mixed and then discharge them.

[0018] S2. Seal and package the finished product with plastic bags. Package it with moisture-proof plastic bags at 10 kg / bag, and then package it with ton bags. Store it in a cool place for storage and transportation, and the shelf life is more than 24 months.

[0019] Compared with the prior art, the present invention provides a breathable seat brick repair material for ladles and its preparation method, which has the following beneficial effects:

[0020] 1. By introducing sodium metasilicate and paraffin powder, the present invention utilizes the decomposition of sodium metasilicate above 300°C to discharge a large amount of water and water vapor, and the melting of paraffin drives the flow of the repair material to fill the gaps. Using sodium metasilicate instead of cement to achieve the binding effect, the sodium salt formed after the decomposition of sodium metasilicate acts as a binder, enabling the repair material to quickly generate strength.

[0021] 2. The breathable seat brick repair material for ladles provided by the present invention is a dry repair material, which can be directly filled and used without adding water for stirring. The operation labor intensity is low, the construction is convenient, and the quality fluctuation caused by uneven mixing is avoided.

[0022] 3. The repair material for the porous seat brick of the ladle provided by the present invention can be used as needed without the need to add water and stir, so there is no need for stirring equipment and site, which improves the repair efficiency and solves the problems such as time-consuming and laborious manual on-site stirring due to the small amount of repair material used during on-site construction.

[0023] 4. The repair material for the porous seat brick of the ladle provided by the present invention has a short decomposition and drying time, does not burst, and has high strength and strong erosion resistance after decomposition and drying, effectively protecting the core of the porous brick and extending its service life.

[0024] 5. The repair material for the porous seat brick of the ladle provided by the present invention can generate fluidity at temperatures above 300°C. The repair material uses the heat of the ladle itself to quickly melt and flow automatically to fill the gaps, and can also use the heat of the ladle itself (1000 - 1200°C) to quickly sinter the repair material, ensuring the dual effects of air permeability and repair of the core of the porous brick. Specific Embodiments

[0025] The present invention will be further described below in conjunction with embodiments:

[0026] The embodiment of the present invention provides a repair material for the porous seat brick of the ladle, and the raw material composition includes: by weight percentage, 70 - 90% of sintered corundum particles and fine powder, 1 - 5% of active magnesium oxide powder, 5 - 15% of active α-aluminum trioxide fine powder, 5 - 10% of sodium metasilicate, and 1 - 5% of paraffin powder.

[0027] In this embodiment, the sintered corundum particles and fine powder include sintered corundum particles with a particle size of 1 - 6 mm and sintered corundum fine powder with a particle size < 0.15 mm. The sintered corundum particles account for 50 - 60%, and the sintered corundum fine powder accounts for 20 - 30%.

[0028] In this embodiment, the particle size of the active magnesium oxide powder < 0.045 mm.

[0029] In this embodiment, the particle size of the active α-aluminum trioxide fine powder < 0.005 mm.

[0030] In this embodiment, the particle size of the sodium metasilicate < 1 mm.

[0031] In this embodiment, the sodium metasilicate is sodium metasilicate nonahydrate.

[0032] Specifically, the sodium metasilicate must be sodium metasilicate nonahydrate because the sodium content of sodium metasilicate nonahydrate is lower than that of sodium metasilicate pentahydrate and sodium metasilicate heptahydrate, but the crystal water content is higher. After adding an equal amount, the fluidity of the repair material will be better, and the low-temperature liquid phase formed after high-temperature sintering is less, and the erosion resistance to molten steel is better.

[0033] In this embodiment, the particle size of the paraffin powder is less than 0.074 mm. Specifically, the particle size of the paraffin powder is less than 0.074 mm. After being evenly mixed, the dispersibility is better and the added amount is correspondingly less, thereby improving the utilization rate of the raw materials.

[0034] In this embodiment, the chemical composition is as follows: by weight percentage, Al 2 O 3 +MgO≥80%.

[0035] In this embodiment, the apparent porosity of the repair material is ≤35%, the compressive strength at room temperature is 110℃*24h≥30MPa, the compressive strength at room temperature is 1500℃*3h≥80MPa, the flexural strength at room temperature is 110℃*24h≥5MPa, the flexural strength at room temperature is 1500℃*3h≥18MPa, and the bulk density is ≥2.4g / cm 3 .

[0036] The above data are the physical and chemical index standards of the repair material, which are organized into a table as shown in Table 1 below:

[0037] Table 1 Chemical index standards for ladle air-permeable brick repair

[0038]

[0039] The method for preparing the above-mentioned air-permeable seat brick repair material for the ladle comprises the following steps:

[0040] S1. Weigh each raw material according to the weight ratio, add it into the mixer after the weight is correct, and stir and mix it. The order of adding the granules first and then the fine powder is to mix for 3-5 minutes after adding the materials. Discharge the materials after the materials are evenly mixed;

[0041] S2. The finished products are sealed in plastic bags, packaged in 10kg / bag moisture-proof plastic bags, and then packaged in ton bags. They are stored and transported in a cool place with a shelf life of more than 24 months.

[0042] Usage method of the breathable seat brick repair material for ladle in the present invention: During construction, place the hot ladle horizontally on the ladle turning machine, connect the backflush gas pipe of the breathable brick core and open the valve, clean the steel and slag adhering to the working end of the breathable brick core and the breathable seat brick with an oxygen lance or a coal-oxygen lance, close the backflush gas and unplug the gas pipe, remove the locking mechanism of the breathable brick core, pull out the used breathable brick core, reinstall the new breathable brick core, then install the locking mechanism of the breathable brick core, connect the gas pipe of the breathable brick core again and open the valve, check whether the breathable brick core is installed in place and the air permeability is normal, if normal, close the gas and unplug the gas pipe. Hoist the treated ladle to the repair position of the breathable seat brick, throw the packaged breathable seat brick repair material from the ladle opening to the working end of the heat-exchanged breathable brick core and the breathable seat brick, wait until the repair material fills the gap between the breathable brick core and the breathable seat brick and fills the height of the breathable seat brick to be basically flush with the bottom of the ladle, and after placing for 5 minutes, the ladle can be put into normal use again. This repair material has good self-flowing performance, excellent sintering performance, good air permeability, fast and convenient construction, and is firmly bonded to the breathable seat brick without falling off.

[0043] Example 1

[0044] A breathable seat brick repair material for ladle, the raw material composition includes: by weight percentage, 50% of sintered corundum particles, 20% of sintered corundum fine powder, 5% of active magnesium oxide powder, 10% of active α-aluminum trioxide fine powder, 10% of sodium metasilicate, and 5% of paraffin powder.

[0045] Preparation method of the breathable seat brick repair material for ladle, including the following steps:

[0046] S1. Weigh each raw material according to the weight ratio, after verifying the weight is correct, add it to the mixer for stirring and mixing, add the particles first and then the fine powder in the feeding order, after adding the materials, mix for 5 minutes, and discharge the materials after the materials are evenly mixed;

[0047] S2. Seal and package the finished product with plastic bags, package it with moisture-proof plastic bags of 10 kg / bag, and then package it with ton bags, store it in a cool place for storage and transportation, and the shelf life is more than 24 months.

[0048] Example 2

[0049] A breathable seat brick repair material for ladle, the raw material composition includes: by weight percentage, 60% of sintered corundum particles, 28% of sintered corundum fine powder, 1% of active magnesium oxide powder, 5% of active α-aluminum trioxide fine powder, 5% of sodium metasilicate, and 1% of paraffin powder.

[0050] Preparation method of the breathable seat brick repair material for ladle, including the following steps:

[0051] S1. Weigh each raw material according to the weight ratio. After verifying the weight is correct, add them to a mixer for stirring and mixing. Add the granular materials first and then the fine powders in this charging order. After adding all the materials, mix for 5 minutes. Wait until the materials are evenly mixed and then discharge them.

[0052] S2. Seal and package the finished product with plastic bags. Package it with moisture-proof plastic bags at 10 kg / bag, and then package it with ton bags. Store it in a cool place for storage and transportation, and the shelf life is more than 24 months.

[0053] Example 3

[0054] A repair material for the breathable seat brick of a ladle, the raw material composition includes: by weight percentage, 55% of sintered corundum particles, 23% of sintered corundum fine powder, 2% of active magnesium oxide powder, 10% of active α-aluminum trioxide fine powder, 7% of sodium metasilicate, and 3% of paraffin powder.

[0055] The preparation method of the repair material for the breathable seat brick of a ladle includes the following steps:

[0056] S1. Weigh each raw material according to the weight ratio. After verifying the weight is correct, add them to a mixer for stirring and mixing. Add the granular materials first and then the fine powders in this charging order. After adding all the materials, mix for 5 minutes. Wait until the materials are evenly mixed and then discharge them.

[0057] S2. Seal and package the finished product with plastic bags. Package it with moisture-proof plastic bags at 10 kg / bag, and then package it with ton bags. Store it in a cool place for storage and transportation, and the shelf life is more than 24 months.

[0058] The following Table 2 shows the detection indexes of several examples of the repair material for the breathable seat brick of the ladle of the present invention

[0059] Table 2 Detection indexes of examples

[0060]

[0061]

[0062] In the present invention, by introducing sodium metasilicate and paraffin powder, a large amount of water and water vapor are discharged due to the decomposition of sodium metasilicate above 300 °C, and the melting of paraffin drives the flow of the repair material to fill the gaps. Sodium metasilicate is used to replace cement to achieve a binding effect, and the sodium salt formed after the decomposition of sodium metasilicate acts as a binder, enabling the repair material to quickly generate strength;

[0063] The repair material for the breathable seat brick of the ladle provided by the present invention is a dry repair material, which can be directly put into use for repair without adding water for stirring. The operation labor intensity is low, the construction is convenient, and the quality fluctuation caused by uneven mixing is avoided;

[0064] The ladle breathable seat brick repair material provided by the present invention can be taken and used at any time, without the need for water stirring, nor the need for stirring equipment and sites, improving the repair efficiency and solving the problems such as time-consuming and laborious manual on-site stirring due to the small amount of repair material used during on-site construction.

[0065] The ladle breathable seat brick repair material provided by the present invention has a short decomposition and drying time, does not burst, and has high strength and strong erosion resistance after decomposition and drying, effectively protecting the breathable brick core and extending its service life.

[0066] The ladle breathable seat brick repair material provided by the present invention can generate fluidity at temperatures above 300°C. The repair material uses the heat of the ladle itself to quickly melt and flow automatically to fill the gaps, and can also use the heat of the ladle itself (1000 - 1200°C) to quickly sinter the repair material, ensuring the dual effects of air permeability and repair of the breathable brick core.

[0067] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on these embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still, without conflict and without creative efforts, combine, add or delete the features in the embodiments of the present invention according to the circumstances, or make other adjustments, so as to obtain different technical solutions that are essentially not divorced from the concept of the present invention, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A breathable seat brick repair material for a ladle, characterized in that: The raw material composition includes: by weight percentage, 70-90% of sintered corundum particles and fine powder, 1-5% of active magnesium oxide powder, 5-15% of active α-aluminum oxide micropowder, 5-10% of sodium metasilicate, and 1-5% of paraffin powder.

2. The air-permeable seat brick repair material for ladle according to claim 1, characterized in that: The sintered corundum particles and fine powder include sintered corundum particles with a particle size of 1-6 mm and sintered corundum fine powder with a particle size less than 0.15 mm, wherein the sintered corundum particles account for 50-60% and the sintered corundum fine powder accounts for 20-30%.

3. The air-permeable seat brick repair material for ladle according to claim 1, characterized in that: The particle size of the active magnesium oxide powder is less than 0.045 mm.

4. The air-permeable seat brick repair material for ladle according to claim 1, characterized in that: The particle size of the active α-alumina micropowder is less than 0.005 mm.

5. The air-permeable seat brick repair material for ladle according to claim 1, characterized in that: The particle size of the sodium metasilicate is less than 1 mm.

6. The air-permeable seat brick repair material for ladle according to claim 5, characterized in that: The sodium metasilicate is sodium metasilicate nonahydrate.

7. The breathable seat brick repair material for ladle according to claim 1, characterized in that: The particle size of the paraffin powder is less than 0.074 mm.

8. The breathable seat brick repair material for ladle according to claim 1, characterized in that: Its chemical composition is: by weight percentage, Al2O3+MgO≥80%.

9. The air-permeable seat brick repair material for ladle according to claim 1, characterized in that: The apparent porosity of the repair material is ≤35%, the compressive strength at room temperature is 110℃*24h≥30MPa, the compressive strength at room temperature is 1500℃*3h≥80MPa, the flexural strength at room temperature is 110℃*24h≥5MPa, the flexural strength at room temperature is 1500℃*3h≥18MPa, and the volume density is ≥2.4g / cm 3 .

10. The method for preparing the air-permeable seat brick repair material for ladle according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Weigh each raw material according to the weight ratio, add it into the mixer after the weight is correct, and stir and mix it. The order of adding the granules first and then the fine powder is to mix for 3-5 minutes after adding the materials. Discharge the materials after the materials are evenly mixed; S2. The finished products are sealed in plastic bags, packaged in 10kg / bag moisture-proof plastic bags, and then packaged in ton bags. They are stored and transported in a cool place with a shelf life of more than 24 months.

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