A fire-resistant magnesia gunning mixture, its preparation method and application

Abstract

The present application relates to the technical field of metallurgical refractory materials, and particularly relates to a refractory magnesia gunning mix, a preparation method and application thereof. The refractory magnesia gunning mix is composed of a base component, an additive and water, wherein the base component comprises sintered magnesia, fused magnesia and industrial solid waste containing a magnesium-based or aluminum-based component. The refractory magnesia gunning mix replaces the high-purity magnesia fine powder traditionally used by the industrial solid waste containing the magnesium-based or aluminum-based component, generates forsterite, cuspidite and magnesium-aluminum spinel complex phase reinforcers in situ at high temperatures, realizes balanced and excellent service performance, has a compressive strength at room temperature of more than 28.8 MPa, has a minimum slag erosion depth of 2.21 mm after being kept at 1600 DEG C for 3 hours, reduces the dependence on natural magnesia resources, cuts down the raw material cost, reduces the mining of natural minerals, and realizes high-value utilization of solid waste.

Description

Technical Field

[0001] This invention relates to the field of metallurgical refractory materials technology, and more particularly to a refractory magnesia spraying material, its preparation method, and its application. Background Technology

[0002] Magnesia-based spraying refractory is a core unshaped refractory material for online rapid repair of metallurgical kilns, effectively extending the service life of kiln linings, reducing the frequency of shutdowns for maintenance, and lowering operation and maintenance costs. Chinese patent CN111470853A discloses a magnesia-based spraying refractory using fused magnesia as the main raw material and aluminate cement, hydrated alumina, and aluminosilicate gel powder as the binding system to improve the room-temperature bonding strength and adhesion performance of the sprayed layer. However, this solution highly relies on high-purity magnesia raw materials (80-95 parts), resulting in high production costs. Furthermore, it does not address the material's defects of large high-temperature shrinkage and poor thermal shock resistance, making the sprayed layer prone to cracking and peeling under alternating hot and cold conditions.

[0003] Magnesia olivine and magnesium aluminate spinel are commonly used reinforcing phases in refractory materials. Introducing them into magnesia-based spraying systems can control sintering shrinkage, optimize high-temperature volume stability, and simultaneously improve mechanical strength and slag erosion resistance, representing a mainstream modification technology direction for high-performance magnesia-based spraying materials. Magnesia olivine has a moderate coefficient of thermal expansion, which can buffer thermal stress generated by rapid heating and cooling, inhibiting crack initiation and propagation; magnesium aluminate spinel has a high melting point and excellent chemical stability, which can block the penetration and erosion of molten slag and iron, strengthening the high-temperature structural stability of the material. Patent CN106116608B discloses a magnesium olivine-carbon spraying material for non-ferrous smelting furnaces, which improves slag resistance by adding magnesium olivine sand. However, this patent uses the method of adding high-purity magnesium olivine and spinel fine powder, which not only further increases the raw material cost but also suffers from problems such as uneven powder dispersion and low interfacial bonding strength between the phase and the matrix, making it difficult to fully utilize the modification advantages of the reinforcing phase.

[0004] The metallurgical industry generates a large amount of industrial solid waste during production, such as waste magnesia spinel bricks, fused magnesia processing waste, high-alumina-based waste, and corundum-based waste. The comprehensive utilization rate of this type of solid waste is low, and long-term stockpiling not only occupies land resources but also wastes mineral resources. CN119263807B discloses a magnesia spinel hot wet spraying material, its preparation method, and its application. It utilizes magnesia spinel brick waste to improve the material's volume stability and erosion resistance. However, the magnesia spinel brick waste used in this patent is residual brick from the lining of an RH circulating vacuum degassing furnace, which is covered with steel slag, molten slag, and metallic impurities. It cannot be used directly and requires multiple processes such as manual sorting, slag removal, and multi-stage iron removal. The pretreatment process is cumbersome and cannot simultaneously meet the requirements of low-cost, green production, and high-performance industrial applications.

[0005] In summary, current magnesia-based spraying materials still suffer from several shortcomings, including high raw material costs, insufficient utilization of solid waste resources, difficulty in achieving a proper balance between high-temperature densification and mechanical properties, and weak resistance to thermal shock and slag-iron erosion. These shortcomings lead to conventional products exhibiting high linear shrinkage and insufficient structural density during high-temperature service, making them prone to spraying layer detachment and service life limitations. Consequently, they are ill-suited to the long-cycle, low-carbon, and low-cost production and maintenance requirements of modern metallurgical kilns. Therefore, developing a refractory magnesia-based spraying material with balanced and excellent service performance, utilizing industrial solid waste as a substitute component, and its preparation process, possesses both significant engineering application value and ecological environmental protection significance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a refractory magnesia spraying material. This refractory magnesia spraying material utilizes magnesium- or aluminum-based industrial solid waste in its preparation, achieving balanced and excellent performance across various service aspects while reducing raw material costs and minimizing the extraction of natural minerals, thus enabling efficient resource utilization of solid waste.

[0007] Another object of the present invention is to provide a method for preparing refractory magnesia spraying material.

[0008] Another objective of this invention is to provide an application of refractory magnesia spray material in the hot repair of converter and ladle linings.

[0009] To achieve the above objectives, the present invention is accomplished through the following technical solutions.

[0010] A refractory magnesia spraying compound, wherein the refractory magnesia spraying compound is composed of the following components:

[0011] The basic components, by mass percentage, include the following components:

[0012] The industrial solid waste is either fused magnesia processing waste or high-alumina-based waste. Fused magnesia processing waste is a byproduct generated during the processing of fused magnesia of different particle sizes. High-alumina-based waste is the product of crushing high-alumina refractory materials after use in the iron and steel metallurgical process. The additive is a mixture of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite; by mass, the ratio of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite is (1~3):(0.5~1.5):(0.5~1.5).

[0013] In the above technical solution, the fused magnesia processing waste includes low-silicon content fused magnesia waste or high-silicon content fused magnesia waste. The SiO2 content in the low-silicon content fused magnesia waste is 1~5 wt%, and the SiO2 content in the high-silicon content fused magnesia waste is 5~10 wt%. The high-alumina based waste includes high-alumina recycled material or bauxite recycled material. The Al2O3 content in the high-alumina recycled material is 50~70 wt%, and the Al2O3 content in the bauxite recycled material is 80~95 wt%.

[0014] In the above technical solution, the chemical composition of the low-silicon content fused magnesia waste includes, by mass percentage: SiO2: 1~5%, Al2O3≤0.5%, Fe2O3: 1~2%, CaO: 2~3%, MgO: 92~97%.

[0015] In the above technical solution, the chemical composition of the high silicon content fused magnesia waste, by mass percentage, includes: SiO2: 5~10%, Al2O3≤0.5%, Fe2O3≤1%, CaO: 0.5~1.5%, MgO: 87~92%.

[0016] In the above technical solution, the chemical composition of the high-alumina recycled material, by mass percentage, includes: Al2O3: 50~70%, SiO2: 30~50%, CaO: 2~5%, MgO: 0.5~1%.

[0017] In the above technical solution, the chemical composition of the bauxite recycled material, by mass percentage, includes: Al2O3: 80~95%, CaO: 2~5%, SiO2: 2~5%, MgO: 1~3%.

[0018] In the above technical solution, the particle size distribution and corresponding mass percentage of the sintered magnesium oxide are as follows:

[0019] In the above technical solution, the purity of the sintered magnesium oxide is ≥95%; the purity of the fused magnesium oxide is ≥97%.

[0020] In the above technical solution, the particle size of the fused magnesium oxide is 0~1 mm; the particle size of the fused magnesia processing waste is ≤75 μm; and the particle size of the high alumina-based waste is ≤75 μm.

[0021] In the above technical solution, the water includes distilled water.

[0022] A method for preparing a refractory magnesia spraying compound specifically includes the following steps: Mix all components except water and dry stir for 1-3 minutes to initially disperse the components evenly. Then slowly add water dropwise at a rate of 5-10 mL / min. After the water dropwise addition is complete, continue wet stirring for 1-3 minutes to form a refractory magnesia spraying material with uniform texture, no obvious particle agglomeration, and suitable flowability.

[0023] In the above technical solution, before dry mixing, all components except water are premixed at a rate of 300~500 r / min for 1~3 min.

[0024] Application of a refractory magnesia spray material in hot repair of converter and ladle linings.

[0025] In the above technical solution, the refractory magnesia spraying material is coated on the converter and ladle lining.

[0026] In the above technical solution, the coating includes spraying, brushing, or roller coating.

[0027] In the above technical solution, the coating is dried at 90~110 ℃ for 24~48 h.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The refractory magnesia spray material of the present invention utilizes magnesium-based or aluminum-based industrial solid waste components to generate magnesium olivine, calcium magnesium olivine and magnesium aluminum spinel multiphase reinforcement in situ at high temperature. It can achieve uniform dispersion and interface strengthening without the need for external high-purity reinforcement phase, thereby achieving a synergistic improvement in density, room temperature strength, thermal shock resistance and erosion resistance.

[0029] (2) The refractory magnesia spraying material of the present invention replaces the traditionally used high-purity magnesia fine powder with magnesia-based or aluminum-based industrial solid waste, which significantly reduces the dependence on natural magnesia resources, reduces raw material costs, reduces the mining of natural minerals, realizes the high-value utilization of bulk solid waste, and meets the requirements of green, low-carbon and circular economic development.

[0030] (3) The present invention uses industrial solid waste components containing magnesium or aluminum as well as reasonable particle size distribution and composite additives to make refractory magnesium spraying material have good construction performance, high temperature volume stability and controllable shrinkage, which can effectively extend the service life of the spraying layer and reduce the frequency of kiln maintenance.

[0031] (4) The preparation process of the refractory magnesium spraying material of the present invention is simple, the conditions are mild, no special equipment is required, it can be adapted to the existing industrial production process, and it is easy to promote and apply. Attached Figure Description

[0032] Figure 1 The X-ray diffraction (XRD) images of magnesia sprayed blanks obtained using the refractory magnesia sprayed materials of Examples 4-6 and Comparative Example 1 of the present invention are shown. Figure 2 Scanning electron microscope (SEM) images of magnesia sprayed blanks obtained using (a) Comparative Example 1 and (b) Example 2 of the present invention; Figure 3 The image shows a cross-sectional SEM image of the refractory magnesia sprayed blank obtained using (a) Comparative Example 1 and (b) Example 1 of the present invention after static crucible slag resistance. Detailed Implementation

[0033] The following examples are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0034] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0035] In the following examples, the purity of sintered magnesium oxide is ≥95%; the purity of fused magnesium oxide is ≥97%.

[0036] In the following embodiments, the fused magnesia processing waste is a byproduct generated during the processing of fused magnesia of different particle sizes; the chemical composition of the low-silicon-content fused magnesia waste is shown in Table 1; and the chemical composition of the high-silicon-content fused magnesia waste is shown in Table 2.

[0037] Table 1

[0038] Table 2

[0039] In the following embodiments, the high-alumina-based waste is the product of crushing high-alumina refractory materials after use in the iron and steel metallurgical process. The chemical composition of the high-alumina recycled material is shown in Table 3; the chemical composition of the bauxite recycled material is shown in Table 4.

[0040] Table 3

[0041] Table 4

[0042] In the following examples, the additive is a mixture of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite, with the ratio of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite being 3:1:1 by mass.

[0043] Example 1 A refractory magnesia spraying compound comprises a base component, an additive comprising 1 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0044] The preparation method of the above-mentioned refractory magnesia spraying material includes the following steps: Accurately weigh each component using an electronic balance with an accuracy of 0.001 g. Place all components except water in a high-speed mixer and premix at 300 r / min for 3 min to ensure initial uniform dispersion. Place the premixed components in the mixing bowl of a mortar mixer and dry-mix for 1 min. Then, while maintaining the mixing state, slowly add distilled water dropwise at a rate of 5 mL / min. After the addition is complete, continue wet-mixing for 1 min to form a refractory magnesia spraying material with a uniform texture, no obvious particle agglomeration, and suitable flowability. Clean the bowl walls promptly during mixing to prevent slurry adhesion and material loss.

[0045] The flow value of the refractory magnesia spraying material in Example 1 was measured to be 185 mm.

[0046] Example 2 A refractory magnesia spraying compound comprises a base component, an additive comprising 2 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0047] The preparation method of the above-mentioned refractory magnesia spraying material includes the following steps: Accurately weigh each component using an electronic balance with an accuracy of 0.001 g. Place all components except water in a high-speed mixer and premix at 400 r / min for 2 min to ensure initial uniform dispersion. Place the premixed components in the mixing bowl of a mortar mixer and dry-mix for 2 min. Then, while maintaining the mixing state, slowly add distilled water dropwise at a rate of 7.5 mL / min. After the addition is complete, continue wet-mixing for 2 min to form a refractory magnesia spraying material with a uniform texture, no obvious particle agglomeration, and suitable flowability. Clean the bowl walls promptly during mixing to prevent slurry adhesion and material loss.

[0048] Example 3 A refractory magnesia spraying compound comprises a base component, an additive comprising 3 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0049] The preparation method of the above-mentioned refractory magnesia spraying material specifically includes the following steps: Accurately weigh each component using an electronic balance with an accuracy of 0.001 g. Place all components except water in a high-speed mixer and premix at 500 r / min for 1 min to ensure initial uniform dispersion. Place the premixed components in the mixing bowl of a mortar mixer and dry-mix for 3 min. Then, while maintaining the mixing state, slowly add distilled water dropwise at a rate of 10 mL / min. After the addition is complete, continue wet-mixing for 3 min to form a refractory magnesia spraying material with a uniform texture, no obvious particle agglomeration, and suitable flowability. Clean the bowl walls promptly during mixing to prevent slurry adhesion and material loss.

[0050] Example 4 A refractory magnesia spraying compound comprises a base component, an additive comprising 1 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0051] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 1.

[0052] Example 5 A refractory magnesia spraying compound comprises a base component, an additive comprising 2 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0053] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 2.

[0054] Example 6 A refractory magnesia spraying compound comprises a base component, an additive comprising 3 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0055] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 3.

[0056] Comparative Example 1 A refractory magnesia spraying compound comprises a base component, an additive comprising 3 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0057] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 1.

[0058] Comparative Example 2 A refractory magnesia spraying compound comprises a base component, an additive comprising 1 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0059] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 1.

[0060] Comparative Example 3 A refractory magnesia spraying compound comprises a base component, an additive comprising 1 wt% of the total mass of the base component, and water comprising 5 wt% of the total mass of the base component. The base component, by mass percentage, includes the following components:

[0061] The preparation method of the above-mentioned refractory magnesia spraying material is the same as that of Example 1.

[0062] The performance of the refractory magnesia sprayed materials in Examples 1-6 and Comparative Examples 1-3 was investigated by the following methods: Step 1, Casting: The refractory magnesia spraying material is poured uniformly into a steel mold, gently shaking the mold during pouring to avoid air bubbles. After pouring, the mold is placed on a vibration table, with a vibration frequency of 50 Hz and a vibration time of 5 s, to ensure the refractory magnesia spraying material is densely formed, guaranteeing a pore-free and uniform structure within the sample. After vibration, excess slurry is scraped off the mold surface with a scraper to ensure a smooth surface and accurate dimensions. The refractory magnesia spraying material used is one of Examples 1-6 and Comparative Examples 1-3.

[0063] Step 2, Curing: Place the mold after casting into a constant temperature and humidity curing chamber, set the temperature to 25 ℃, and cure for 48 h to ensure that the refractory magnesia sprayed material is fully hydrated and formed and obtains the initial strength that meets the demolding requirements.

[0064] Step 3, Drying: Place the demolded magnesium spraying material green sample into a drying oven and dry at a constant temperature of 110 ℃ for 24 h to completely remove the internal bound water; after drying, turn off the power and let it cool naturally to room temperature before taking it out.

[0065] Step 4, heat treatment: The dried magnesium spraying material green sample is placed in a high-temperature muffle furnace and heat-treated at 1550 ℃ for 3 h to obtain the magnesium spraying material green body.

[0066] The bulk density of the magnesium spraying blank was measured, and the diameter of the magnesium spraying blank before and after heat treatment was compared to obtain the linear shrinkage rate. The bulk density and linear shrinkage rate of the magnesium spraying blanks obtained in Examples 1-6 and Comparative Examples 1-3 are shown in Table 5.

[0067] XRD tests were performed on the magnesia sprayed blanks obtained from Examples 4-6 and Comparative Example 1, as shown in the results. Figure 1 As shown, by Figure 1 It can be seen that, compared with Comparative Example 1, the refractory magnesia spraying materials of Examples 4 to 6 generate a multiphase reinforcement of forsterite, calcium magnesium olivine and magnesium aluminum spinel in situ at high temperature, which effectively inhibits the excessive sintering of the matrix, thereby giving the magnesia spraying material blank excellent high-temperature volume stability and controllable linear shrinkage rate.

[0068] The magnesia-sprayed blanks obtained using the refractory magnesia-sprayed materials of Example 2 and Comparative Example 1 were characterized by SEM, such as... Figure 2 As shown, by Figure 2 It can be seen that the surface of the magnesium spraying material blank prepared in Example 2 is relatively flat, the grains are more tightly bonded, the number of internal pores is small and the distribution is uniform, and the overall density is good. In contrast, the magnesium spraying material blank prepared in Comparative Example 1 has a loose microstructure, the grains are of uneven size and randomly distributed, and the number of internal pores is large and the connectivity is strong. Therefore, its density is significantly worse than that of Example 2.

[0069] The room temperature compressive strength of the magnesium spraying material blank was tested. The magnesium spraying material blank was further heated to 1100 ℃ and held for half an hour, then air-cooled to room temperature. After three cycles, its room temperature compressive strength was tested again, and the residual strength retention rate was calculated. The results are shown in Table 5. The resistance to converter slag erosion depth was tested using the static crucible slag resistance method with a holding temperature of 1600 ℃ for 3 h. The results are shown in Table 5. Simultaneously, after the test, the cross-sections of the magnesia-sprayed blanks obtained using the refractory magnesia-sprayed materials of Example 1 and Comparative Example 1 were characterized by SEM. Figure 3 As shown. By Figure 3 It can be seen that the slag-liquid mixture forms three layers during the erosion process, with the top layer being the slag erosion layer. Figure 3 The middle layer is the "Erosion layer" and the middle layer is the permeation layer. Figure 3 The middle layer is called the "Penetration layer," and the bottom layer is the original refractory spraying substrate. Figure 3 (The term "Original layer" is used in the original text). After erosion, the thickness of the penetrating layer of the magnesium spraying material blank prepared in Example 1 is significantly smaller than that in Comparative Example 1, indicating that it has a superior resistance to slag erosion.

[0070] Table 5

[0071] As shown in Table 5, the embodiments of the present invention utilize magnesium-based or aluminum-based industrial solid waste to make the refractory magnesia sprayed material have more magnesium olivine phase in the magnesia sprayed material blank, which alleviates the interfacial stress concentration caused by thermal mismatch and significantly inhibits the cracking and peeling tendency of the sprayed layer, thereby greatly extending its service life. In addition, thanks to the synergistic strengthening effect of spinel phase and matrix components, the mechanical strength of refractory magnesia sprayed material at room temperature and medium and high temperature is significantly improved, fully meeting the multiple performance requirements of refractory materials under harsh high temperature conditions.

[0072] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A refractory magnesia spraying compound, characterized in that, The refractory magnesia spraying material is composed of the following components: The basic components, by mass percentage, include the following components: The industrial solid waste is either fused magnesia processing waste or high-alumina-based waste. Fused magnesia processing waste is a byproduct generated during the processing of fused magnesia of different particle sizes. High-alumina-based waste is the product of crushing high-alumina refractory materials after use in the iron and steel metallurgical process. The additive is a mixture of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite; by mass, the ratio of sodium hexametaphosphate, readily soluble sodium silicate, and sodium bentonite is (1~3):(0.5~1.5):(0.5~1.5).

2. The refractory magnesia spraying material according to claim 1, characterized in that, The fused magnesia processing waste includes low-silicon fused magnesia waste or high-silicon fused magnesia waste. The low-silicon fused magnesia waste contains 1-5 wt% SiO2, and the high-silicon fused magnesia waste contains 5-10 wt% SiO2. The high-alumina based waste includes high-alumina recycled material or bauxite recycled material. The high-alumina recycled material contains 50-70 wt% Al2O3, and the bauxite recycled material contains 80-95 wt% Al2O3.

3. The refractory magnesia spraying material according to claim 2, characterized in that, The chemical composition of the low-silicon content fused magnesia waste, by mass percentage, includes: SiO2: 1~5%, Al2O3≤0.5%, Fe2O3: 1~2%, CaO: 2~3%, MgO: 92~97%; The chemical composition of the high-silicon content fused magnesia waste, by mass percentage, includes: SiO2: 5~10%, Al2O3≤0.5%, Fe2O3≤1%, CaO: 0.5~1.5%, MgO: 87~92%; The chemical composition of the high-alumina recycled material, by mass percentage, includes: Al2O3: 50~70%, SiO2: 30~50%, CaO: 2~5%, MgO: 0.5~1%; The chemical composition of the recycled bauxite material, by mass percentage, includes: Al2O3: 80~95%, CaO: 2~5%, SiO2: 2~5%, MgO: 1~3%.

4. The refractory magnesia spraying material according to claim 1, characterized in that, The particle size distribution and corresponding mass percentage of the sintered magnesium oxide are as follows: 。 5. The refractory magnesia spraying material according to claim 1, characterized in that, The purity of the sintered magnesium oxide is ≥95%; the purity of the fused magnesium oxide is ≥97%.

6. The refractory magnesia spraying material according to claim 1, characterized in that, The particle size of the fused magnesium oxide is 0~1mm; the particle size of the fused magnesia processing waste is ≤75 μm; the particle size of the high alumina-based waste is ≤75 μm.

7. The method for preparing the refractory magnesia spraying material according to any one of claims 1 to 6, characterized in that, Specifically, the following steps are included: Mix all components of the refractory magnesia spraying material according to any one of claims 1 to 6 except water, dry stir for 1 to 3 minutes, then add water dropwise at a rate of 5 to 10 mL / min, and continue wet stirring for 1 to 3 minutes after the addition is complete to form the refractory magnesia spraying material.

8. The preparation method according to claim 7, characterized in that, Before dry mixing, all components of the refractory magnesia spraying material according to any one of claims 1 to 6, except for water, are premixed at a rate of 300 to 500 r / min for 1 to 3 min.

9. The application of the refractory magnesia spraying material according to any one of claims 1 to 6 in the hot repair of converter and ladle linings.

10. The application according to claim 9, characterized in that, The refractory magnesia spraying material is applied to the inner lining of the converter and ladle.

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