A refractory material resistant to manganese-iron corrosion and its preparation method

Abstract

This invention relates to the field of refractory materials, specifically to a refractory material resistant to manganese ferroalloy (MFC) erosion and its preparation method. It addresses the problems of existing refractory materials suffering from long-term MFC erosion, carbon oxidation leading to micropores, and unstable boundary conditions causing a decrease in the melting point of the reactive metamorphic layer, resulting in MFC erosion growing inwards and a short service life. The working layer, by weight, consists of 80-95 parts of ASC brick base material, 2-7 parts of modified filler, and 10-20 parts of interface isolation material. The modified filler is barium zirconate or zirconium silicate, and the modified material is tantalum nitride. The mass ratio of filler to tantalum nitride is 1-6:1. The interface isolation material is composed of magnesium phosphate, aluminum phosphate, and tungsten carbide, with a mass ratio of magnesium phosphate, aluminum phosphate, and tungsten carbide of 4-6:4-6:8-12. This invention enables the refractory material to possess extremely high MFC resistance, significantly extending its service life.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a refractory material resistant to manganese-iron corrosion and its preparation method. Background Technology

[0002] The development of refractory materials involves multiple stages. Initially, high-alumina bricks were used, which contain silicon dioxide, leading to an increase in the silicon content of molten steel. This led to the development of alumina-magnesia-carbon bricks. However, carbon composites have poor oxidation resistance and low strength, so silicon carbide composites were used instead. But carbon leads to an increase in carbon in molten steel, so the development of low-carbon magnesium aluminum nitride oxides was pursued, which can effectively support high-temperature molten iron. Currently, the development and research of medium and high manganese steel show that manganese steel has excellent strength and wear resistance, making it a key material for heavy industry and machinery manufacturing.

[0003] However, the presence of manganese in ferromanganese molten iron has a significant destructive effect on refractory materials. A large amount of blackish-green substance often forms on the surface of refractory materials in contact with high-manganese steel. This substance is manganese monoxide impurities formed by the oxidation of manganese in the steel. Therefore, the use of silica-based inorganic refractory materials is not advisable. Currently, ASC bricks are widely used as the mainstream choice for supporting ferromanganese molten iron. However, long-term use has revealed that the actual service life of this material is not long. The oxidation rate of carbon is affected by the oxides of manganese and iron, accelerating the oxidation of carbon. Since carbon accounts for approximately 30% of the content in ASC bricks, long-term use... Under interstitial corrosion, numerous micropores are generated. In addition, all other refractory materials are composed of oxides. Under high-temperature conditions, refractory oxides will dissolve or decompose, thereby increasing the content of other impurity elements in the molten steel. As dissolution proceeds, an interfacial isolation layer will gradually form between the molten steel and the refractory material. Manganese elements will transfer back into the refractory material. During the transfer of manganese elements, they react with the oxidizing substances in the interfacial isolation layer to generate a reaction-modified layer with a lower melting point, causing the stable interfacial isolation layer to collapse. This allows the manganese molten steel to penetrate into the new refractory material, promoting the growth of the interfacial isolation layer into the interior of the refractory material.

[0004] The above are the problems that existing refractory materials face when dealing with molten manganese iron. One is that carbon is oxidized to form pores, and molten steel penetrates inward along the pores. The other is that the melting point of the interfacial barrier layer formed between the molten steel and the refractory material decreases, causing it to erode inward. Summary of the Invention

[0005] To address the problems of long-term manganese-ferromanganese erosion in existing refractory materials, the formation of micropores due to carbon oxidation, and the instability of the reactive metamorphic layer on the refractory surface due to a decrease in melting point, leading to manganese-ferromanganese erosion growing into the interior of the refractory material and a short service life, this invention provides a refractory material resistant to manganese-ferromanganese erosion and its preparation method.

[0006] The technical solution adopted in this invention is as follows:

[0007] A refractory material resistant to manganese-iron corrosion includes a permanent layer and a working layer, wherein the working layer is composed of 80-95 parts by weight of ASC brick base material, 2-7 parts by weight of modified filler and 10-20 parts by weight of interface isolation material.

[0008] The modified filler is barium zirconate or zirconium silicate, and the modifying material is tantalum nitride. The mass ratio of the filler to the tantalum nitride is 1-6:1.

[0009] The interface isolation material is composed of magnesium phosphate, aluminum phosphate and tungsten carbide, with a mass ratio of magnesium phosphate, aluminum phosphate and tungsten carbide of 4-6:4-6:8-12.

[0010] This application uses barium zirconate or zirconium silicate, high-melting-point materials, to construct a complex anti-corrosion filling layer on the basis of existing ASC bricks. The surface of the layer is modified with tantalum nitride to block the pores, thereby preventing carbon from being oxidized and forming corrosion paths. Using barium zirconate or zirconium silicate as the filling layer not only provides high material strength for long-term use, but also enhances the density of the ASC brick surface during the modification process, making it more resistant to manganese and iron corrosion.

[0011] Zirconium can form a high-melting-point protective barrier at high temperatures, significantly improving the material's corrosion resistance. It also has a certain coefficient of thermal expansion at high temperatures, which can seal gaps and prevent molten manganese and iron from corroding the interior. Tantalum, as a filler material, plays a crucial role due to its extremely high melting point, far exceeding that of metals. It will not react with molten steel, protecting the internal "filler" barium zirconate or zirconium silicate from damage. Furthermore, tantalum forms tantalum nitride during subsequent preparation. TaN has a density about 10% lower than Ta, greatly increasing the density of the porous material and effectively sealing the pores.

[0012] Secondly, magnesium phosphate, aluminum phosphate, and tungsten carbide are used as the outermost layer of the refractory material. The tungsten carbide skeleton and the immiscible magnesium phosphate and aluminum phosphate phases serve as a dynamic isolation layer to prevent corrosion from molten manganese steel. Magnesium phosphate and aluminum phosphate melt at 1200-1400°C to form a semi-solid viscous layer. This viscous layer can flow and fill microcracks, thus maintaining the integrity of the refractory material surface. Most importantly, magnesium phosphate and aluminum phosphate are in an ionic state at high temperatures, belonging to an ionic structure, while molten steel is a metallic structure. The two are immiscible, so this dynamic liquid phase layer of magnesium phosphate and aluminum phosphate prevents direct contact between molten steel and the refractory material, preventing the dissolution and collapse of the refractory material and extending its service life.

[0013] Preferably, the ASC brick base material is sintered by mixing 45-65 parts corundum, 15-25 parts silicon carbide, 10-20 parts graphite, 8-12 parts aluminum dihydrogen phosphate, and 2-3 parts pure aluminum powder.

[0014] Preferably, the graphite has a particle size of 0.125-0.500 mm, wherein the proportion of graphite with a particle size of 0.125-0.300 mm is 60%, and the proportion of graphite with a particle size of 0.300 mm-0.500 mm is 40%.

[0015] This specific gravity of graphite can create enough pores to supply the filling formation of barium zirconate or zirconium silicate and tantalum nitride, with pores that are neither too few nor too large.

[0016] Preferably, the permanent layer is composed of 60-70 parts by weight of alumina, 5-10 parts by weight of aluminum silicate, 5-8 parts by weight of silicon powder, 15-20 parts by weight of silicon dioxide, and 0.1-1 parts by weight of sodium tripolyphosphate.

[0017] This application also provides a method for preparing the above-mentioned refractory material resistant to manganese-iron corrosion, the specific preparation steps of which are as follows:

[0018] S1. Construction of the microporous structure of ASC bricks: ASC bricks are heated to 650-750℃ for heat treatment in an oxygen atmosphere for 2-4 hours with an atmosphere introduction rate of 5-10 L / min, and then cooled to obtain a porous surface material.

[0019] S2. Preparation of modified filler: The surface porous matrix is ​​placed in an aqueous solution of zirconium oxychloride and ammonia is added dropwise to form a precipitate. Then the surface porous matrix is ​​taken out and placed in an ethylenediamine solution of barium salt. After stirring, it is heated and reacted at 160-220℃ for 12-36h. After washing, the loaded porous matrix is ​​obtained.

[0020] The loaded porous matrix is ​​then modified, and the specific modification steps are as follows:

[0021] Tantalum powder was coated onto the surface of a supported porous substrate, then heat-treated at high temperature in an ammonia atmosphere, and then placed in a nitrogen-containing electrolyte for electrolytic treatment for 0.5-2 hours with a pulse current of 10-100 kHz to obtain a modified filler.

[0022] S3. Preparation of interface isolation material: Weigh magnesium phosphate, aluminum phosphate and tungsten carbide and mix them to obtain an isolation material. Press the isolation material onto the outside of the modified filler by cold isostatic pressing to form a rough blank. Heat treat the rough blank to form an interface isolation material.

[0023] This application removes graphite from the surface of ASC bricks through heat treatment in an oxygen atmosphere, creating numerous small micropores that serve as filling sites for the filler. The filler is then applied using a hydrothermal treatment with a solution of zirconium oxychloride and barium salts, forming a solid precipitate that settles within the micropores. Subsequent tantalum nitride modification employs electrolytic treatment, resulting in a denser nitride layer and repairing surface defects from the previous hydrothermal treatment. The selected pulsed current promotes rapid diffusion of nitrogen atoms, and the volume expansion during nitride does not disrupt the surface continuity but rather grows along the micropores and the gaps in the filler, thus obtaining a high-quality nitride layer with exceptional corrosion resistance.

[0024] Preferably, in step S1, the cooling is performed at a uniform rate of 50°C / h.

[0025] Preferably, the ratio of zirconium oxychloride to barium salt is 1:1, and the concentrations of both zirconium oxychloride and barium salt are 5-50 mmol / mL, while the concentration of ammonia water is 30 wt%.

[0026] Preferably, the temperature of the high-temperature treatment in the ammonia atmosphere in step S2 is 800-1000℃.

[0027] Preferably, the nitrogen-containing electrolyte in step S2 is an organic-inorganic composite electrolyte, wherein the organic substance is urea, ethylenediamine or melamine, and the inorganic material is ammonium nitrate, potassium nitrate, ammonium sulfate or ammonium phosphate.

[0028] Preferably, in step S3, the pressure of cold isostatic pressing of the isolation material is 300-600 MPa, the cold isostatic pressing time is 5-10 min, the heat treatment temperature is 1200-1350℃, the heat treatment time is 3-12 h, and Co or Ni is added as a sintering binder, with the amount of sintering binder used being 2-4%.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. This application coarsens the graphite component on the surface of the refractory material, which is easily oxidized, and uses a hydrothermal reaction to fill the micropores with a high-melting-point blocking substance. Furthermore, it electrolyzes a layer of tantalum nitride with an extremely high melting point on the surface and utilizes its volume expansion under electrochemical changes to densify the surface of the refractory material. This greatly increases the corrosion resistance of the refractory material and is a solution to prevent molten steel from penetrating into the interior of the refractory material along the pores.

[0031] 2. This application uses magnesium phosphate and aluminum phosphate, which are in an ionic state at high temperatures, and are immiscible with molten manganese steel, serving as a dynamic isolation layer. Furthermore, the tungsten carbide framework serves as the support framework for the liquid-phase magnesium phosphate and aluminum phosphate, which can stabilize the liquid-phase layer of magnesium phosphate and aluminum phosphate from the influence of other external forces. Attached Figure Description

[0032] Figure 1 The figures show experimental data from embodiments and comparative examples of the present invention.

[0033] Figure 2 The figures show experimental data from embodiments and comparative examples of the present invention. Detailed Implementation

[0034] The following will refer to the attached reference. Figures 1 to 2 The various embodiments of the present invention will be described in detail below. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] Preparation Example 1

[0036] Preparation of ASC bricks

[0037] Weigh 50 parts corundum, 20 parts silicon carbide, 15 parts graphite, 10 parts aluminum dihydrogen phosphate, and 2.5 parts pure aluminum powder. Select graphite with a particle size of 0.125-0.500 mm, of which 60% is graphite with a particle size of 0.125-0.300 mm and 40% is graphite with a particle size of 0.300 mm-0.500 mm. Crush the lumps into particles with a particle size of 0.5-5 mm. Mix all the weighed materials and add 12% water by weight of the dry materials to prepare a rough blank. Place it in a sintering furnace for oxygen-free firing at a firing temperature of 1650℃ for 12 hours to obtain ASC brick base material.

[0038] Preparation Example 2 – Using Graphite with Extremely Small Particle Size

[0039] Preparation of ASC bricks

[0040] Weigh 45 parts corundum, 15 parts silicon carbide, 10 parts graphite, 8 parts aluminum dihydrogen phosphate, and 2 parts pure aluminum powder. Select graphite powder with a particle size of less than 0.125 mm. Crush the lumps into particles with a particle size of 0.5-5 mm. Mix all the weighed materials and add 12% water by weight of the dry materials to prepare a rough blank. Place it in a sintering furnace for oxygen-free firing at a firing temperature of 1500℃ for 10 hours to obtain ASC brick base material.

[0041] Preparation Example 3 – Graphite Particle Size Too Large

[0042] Preparation of ASC bricks

[0043] Weigh 65 parts corundum, 25 parts silicon carbide, 20 parts graphite, 12 parts aluminum dihydrogen phosphate, and 3 parts pure aluminum powder. Select graphite with a particle size greater than 0.500 mm. Crush the lumps into particles with a particle size of 0.5-5 mm. Mix all the weighed materials and add 12% water by weight of the dry materials to prepare a rough blank. Place it in a sintering furnace for oxygen-free firing at a firing temperature of 1750℃ for 20 hours to obtain ASC brick base material.

[0044] Example 1

[0045] Preparation of refractory materials resistant to manganese-iron corrosion

[0046] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0047] S2. Weigh 90 parts by weight of the surface porous substrate and place it in a 20 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 20 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 200°C for 20 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is 3 parts by weight more than that of the surface porous substrate in S1.

[0048] Tantalum powder with a particle size of 20-50 micrometers was coated onto the surface of a supported porous substrate and heat-treated to 900℃ in an ammonia atmosphere. Then, a 60wt% inorganic nitrogen ammonium nitrate aqueous solution was prepared. Organic nitrogen urea was weighed and added to the 60wt% inorganic nitrogen ammonium nitrate aqueous solution to form a composite electrolyte with a urea concentration of 30wt%. The supported porous substrate was placed in the electrolyte, and the composite electrolyte was energized with a pulse current of 60kHz for 1 hour to obtain a modified filler. The modified filler was 1 part by weight more than the supported porous substrate.

[0049] S3. Weigh and mix magnesium phosphate, aluminum phosphate and tungsten carbide in a mass ratio of 5:5:10 to obtain a separator material. Press 15 parts by weight of the separator material onto the outside of the modified filler to form a rough blank by cold isostatic pressing at a pressure of 450 MPa for 8 minutes. Heat treat the rough blank at a temperature of 1300℃ for 8 hours to form an interface separator material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0050] Example 2

[0051] Preparation of refractory materials resistant to manganese-iron corrosion

[0052] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 650°C for 2 hours. The oxygen was introduced at a rate of 5 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0053] S2. Weigh 80 parts by weight of the surface porous substrate and place it in a 5 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 5 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 160°C for 12 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is increased by 1 part by weight compared with the surface porous substrate in S1.

[0054] Tantalum powder with a particle size of 20-50 micrometers was coated onto the surface of a supported porous substrate and heat-treated to 800℃ in an ammonia atmosphere. Then, a 60wt% inorganic nitrogen ammonium sulfate aqueous solution was prepared. An organic nitrogen ethylenediamine was weighed and added to the 60wt% inorganic nitrogen ammonium sulfate aqueous solution to form a composite electrolyte with an ethylenediamine concentration of 30wt%. The supported porous substrate was placed in the electrolyte, and the composite electrolyte was energized with a pulse current of 10kHz for 0.5h to obtain a modified filler. The modified filler was 1 part by weight more than the supported porous substrate.

[0055] S3. Weigh and mix magnesium phosphate, aluminum phosphate and tungsten carbide in a mass ratio of 4:4:12 to obtain a separator material. Press 10 parts by weight of the separator material onto the outside of the modified filler to form a rough blank by cold isostatic pressing at a pressure of 300 MPa for 5 minutes. Heat treat the rough blank at a temperature of 1200℃ for 3 hours to form an interface separator material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0056] Example 3

[0057] Preparation of refractory materials resistant to manganese-iron corrosion

[0058] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 750°C for 4 hours. The oxygen was introduced at a rate of 10 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0059] S2. Weigh 95 parts by weight of the surface porous substrate and place it in a 50 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 50 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 220°C for 36 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is 6 parts by weight more than that of the surface porous substrate in S1.

[0060] Tantalum powder with a particle size of 20-50 micrometers was coated onto the surface of a supported porous substrate and heat-treated to 1000℃ in an ammonia atmosphere. Then, a 60wt% inorganic nitrogen ammonium phosphate aqueous solution was prepared. Organic nitrogen melamine was weighed and added to the 60wt% inorganic nitrogen ammonium phosphate aqueous solution to form a composite electrolyte with a melamine concentration of 30wt%. The supported porous substrate was placed in the electrolyte, and the composite electrolyte was energized with a pulse current of 100kHz for 2 hours to obtain a modified filler. The modified filler was 1 part by weight more than the supported porous substrate.

[0061] S3. Weigh and mix magnesium phosphate, aluminum phosphate, and tungsten carbide in a mass ratio of 6:6:8 to obtain a separator material. Mix 20 parts by weight of the separator material with 3% of the total weight of Co sintering binder and then press it onto the outside of the modified filler by cold isostatic pressing to form a rough blank. The pressure is 600 MPa and the cold isostatic pressing time is 10 min. The rough blank is then heat-treated at a temperature of 1350℃ for 12 h to form an interface separator material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0062] Comparative Example 1 – ASC bricks were prepared from Preparation Example 2

[0063] Preparation of refractory materials resistant to manganese-iron corrosion

[0064] S1. The ASC brick prepared in Preparation Example 2 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0065] The remaining steps are the same as the preparation steps in Example 1.

[0066] Comparative Example 2 – ASC bricks were prepared from Preparation Example 3

[0067] Preparation of refractory materials resistant to manganese-iron corrosion

[0068] S1. The ASC brick prepared in Preparation Example 3 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0069] The remaining steps are the same as the preparation steps in Example 1.

[0070] Comparative Example 3 – ASC bricks did not have a microporous structure.

[0071] Preparation of refractory materials resistant to manganese-iron corrosion

[0072] S1. Weigh 90 parts by weight of the ASC brick prepared in Example 1 and place it in a 20 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the ASC brick and place it in an ethylenediamine solution of barium salt with a concentration of 20 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring the reaction, heat the ASC brick and the ethylenediamine solution of barium salt at 200°C for 20 h. After washing with water, the loaded ASC brick is obtained. The loaded ASC brick is 3 parts by weight more than the ASC brick in S1.

[0073] Tantalum powder with a particle size of 20-50 micrometers was coated onto the surface of the supported ASC brick. The brick was then heat-treated at 900°C in an ammonia atmosphere. A 60wt% inorganic nitrogen ammonium nitrate aqueous solution was prepared by weighing and adding organic nitrogen urea to the 60wt% inorganic nitrogen ammonium nitrate aqueous solution to form a composite electrolyte with a urea concentration of 30wt%. The ASC brick was placed in the composite electrolyte, and an electric current of 60kHz was applied to the composite electrolyte for 1 hour to obtain a modified ASC brick. The modified ASC brick was 1 part by weight more than the supported ASC brick.

[0074] S2. Weigh and mix magnesium phosphate, aluminum phosphate and tungsten carbide in a mass ratio of 5:5:10 to obtain a separating material. Press 15 parts by weight of the separating material onto the outside of the modified ASC brick to form a rough blank by cold isostatic pressing at a pressure of 450 MPa for 8 minutes. Heat treat the rough blank at a temperature of 1300℃ for 8 hours to form an interface separating material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0075] Comparative Example 4 – Filler without tantalum nitride modification

[0076] Preparation of refractory materials resistant to manganese-iron corrosion

[0077] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0078] S2. Weigh 90 parts by weight of the surface porous substrate and place it in a 20 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 20 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 200°C for 20 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is 3 parts by weight more than that of the surface porous substrate in S1.

[0079] S3. Weigh and mix magnesium phosphate, aluminum phosphate and tungsten carbide in a mass ratio of 5:5:10 to obtain a separator material. Press 15 parts by weight of the separator material onto the outside of the load porous matrix to form a rough blank by cold isostatic pressing at a pressure of 450 MPa for 8 minutes. Heat treat the rough blank at a temperature of 1300℃ for 8 hours to form an interface separator material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0080] Comparative Example 5 – No tungsten carbide was used in the interface isolation material.

[0081] Preparation of refractory materials resistant to manganese-iron corrosion

[0082] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0083] S2. Weigh 90 parts by weight of the surface porous substrate and place it in a 20 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 20 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 200°C for 20 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is 3 parts by weight more than that of the surface porous substrate in S1.

[0084] Tantalum powder with a particle size of 20-50 micrometers was coated onto the surface of a supported porous substrate and heat-treated to 900℃ in an ammonia atmosphere. Then, a 60wt% inorganic nitrogen ammonium nitrate aqueous solution was prepared. Organic nitrogen urea was weighed and added to the 60wt% inorganic nitrogen ammonium nitrate aqueous solution to form a composite electrolyte with a urea concentration of 30wt%. The supported porous substrate was placed in the electrolyte, and the composite electrolyte was energized with a pulse current of 60kHz for 1 hour to obtain a modified filler. The modified filler was 1 part by weight more than the supported porous substrate.

[0085] S3. Weigh and mix magnesium phosphate and aluminum phosphate in a mass ratio of 5:5 to obtain a separator material. Press 15 parts by weight of the separator material onto the outside of the modified filler to form a rough blank. The pressure is 450 MPa and the cold isostatic pressing time is 8 min. Heat treat the rough blank at a temperature of 1300℃ for 8 h to form an interface separator material and obtain a refractory material resistant to manganese and iron corrosion.

[0086] Comparative Example 6 – Nitrogen-containing electrolyte was not used during the electrochemical treatment of tantalum powder.

[0087] Preparation of refractory materials resistant to manganese-iron corrosion

[0088] S1. The ASC brick prepared in Preparation Example 1 was placed in oxygen and heated to 700°C for 3 hours. The oxygen was introduced at a rate of 8 L / min. Then, it was cooled to room temperature at a rate of 50°C / h to obtain a porous surface substrate.

[0089] S2. Weigh 90 parts by weight of the surface porous substrate and place it in a 20 mmol / mL zirconium oxychloride aqueous solution. Add 30 wt% ammonia water to the solution. After the reaction is complete, take out the surface porous substrate and place it in an ethylenediamine solution of barium salt with a concentration of 20 mmol / mL. The molar ratio of zirconium oxychloride to barium salt is 1:1. After stirring and reacting, heat the surface porous substrate and the ethylenediamine solution of barium salt at 200°C for 20 h. After washing with water, the loaded porous substrate is obtained. The weight of the loaded porous substrate is 3 parts by weight more than that of the surface porous substrate in S1.

[0090] Tantalum powder with a particle size of 20-50 micrometers was coated on the surface of the supported porous matrix and heat-treated to 900℃ in an ammonia atmosphere. Then, a 60wt% lithium hexafluorophosphate electrolyte was prepared. The supported porous matrix was placed in the electrolyte, and the electrolyte was energized with a pulse current of 60kHz for 1 hour to obtain the modified filler. The modified filler was 1 part by weight more than the supported porous matrix.

[0091] S3. Weigh and mix magnesium phosphate, aluminum phosphate and tungsten carbide in a mass ratio of 5:5:10 to obtain a separator material. Press 15 parts by weight of the separator material onto the outside of the modified filler to form a rough blank by cold isostatic pressing at a pressure of 450 MPa for 8 minutes. Heat treat the rough blank at a temperature of 1300℃ for 8 hours to form an interface separator material, thus obtaining a refractory material resistant to manganese-iron corrosion.

[0092] Experiments and Data

[0093] The refractory materials resistant to manganese-iron corrosion prepared in the above embodiments and comparative examples were used as linings and combined with an integrally cast permanent layer to form a manganese-iron molten iron ladle. The permanent layer consisted of 65 parts by weight of alumina, 7 parts by weight of aluminum silicate, 6 parts by weight of silica powder, 18 parts by weight of silicon dioxide, and 0.5 parts by weight of sodium tripolyphosphate. The refractory materials were subjected to relevant tests to ensure they could withstand the manganese-iron molten iron. The specific experiments are as follows:

[0094] Thermal shock resistance test: The test was conducted in accordance with GB / T30873-2014 standard, and the unit is the residual strength retention rate: %.

[0095] Antioxidant resistance test: The test was conducted in accordance with GB / T17732-2008 standard. The unit is oxide layer thickness: mm. The erosion rate in Table 1 was tested under the background of 2h pouring time, 1580℃ pouring temperature and 13.5% manganese content.

[0096] Corrosion resistance test: Tested according to GB / T8931-2007 standard, unit is corrosion rate: %.

[0097] The specific data is shown in Table 1 below:

[0098] Table 1

[0099]

[0100]

[0101] Line graphs were plotted to represent the residual strength retention rate and erosion rate in Table 1 above, as shown below. Figure 1 As shown.

[0102] A bar chart was plotted to represent the oxide layer thicknesses in Table 1 above, as shown below. Figure 2 As shown.

[0103] analyze

[0104] According to the data in Table 1, the refractory materials resistant to manganese-iron corrosion in Examples 1, 2 and 3 can withstand high-temperature molten iron with a manganese content of 15% and maintain good strength. They are less corroded and have very little oxidation, which can greatly improve their resistance to manganese-iron molten iron and greatly extend the service life of the refractory materials.

[0105] According to the data in Table 1, the refractory material prepared in Comparative Example 1 showed a significant decrease in residual strength retention, a moderate oxide layer thickness, and a reduced erosion rate. The difference between Comparative Example 1 and Example 1 lies in the fact that the graphite particles in the ASC brick have a particle size of less than 0.125 mm. The graphite particle size is related to the subsequent heat treatment and can significantly control the size of the pores generated during the heat treatment process. This demonstrates that a suitable graphite particle size can ensure the entry of filler and the sealing effect of tantalum nitride, thereby improving the refractory performance of the refractory material.

[0106] According to the data in Table 1, the refractory material prepared in Comparative Example 2 showed a significant decrease in residual strength retention, a moderate oxide layer thickness, and a substantial decrease in erosion rate. The difference between Comparative Example 2 and Example 1 is that the graphite particles in the ASC brick have a particle size greater than 0.500 mm. This demonstrates that a suitable graphite particle size ensures that the micropores are not too large, and that the appropriate particle size allows the heat treatment to achieve its maximum effect without retaining carbon elements that are oxidized by manganese and iron to form new pores. This significantly improves the strength and erosion resistance of the refractory material.

[0107] According to the data in Table 1, the refractory material prepared in Comparative Example 3 showed a smaller decrease in residual strength retention, a larger oxide layer thickness, and a significant decrease in erosion rate. The difference between Comparative Example 3 and Example 1 is that the ASC brick did not have a microporous structure. This proves that the establishment of a microporous structure can provide sufficient specific surface area, thereby depositing sufficient filling material to block the pores and provide strong blocking when subjected to manganese-iron erosion, thus improving the resistance to manganese-iron erosion.

[0108] According to the data in Table 1, the refractory material prepared in Comparative Example 4 showed a smaller decrease in residual strength retention, a moderate oxide layer thickness, and a significant decrease in erosion rate. The difference between Comparative Example 4 and Example 1 is that the filler was not modified with tantalum nitride. This demonstrates that the modification with tantalum nitride can effectively seal the gaps caused by heat treatment. The volume expansion from tantalum to tantalum nitride can greatly reduce the damage caused by manganese-iron erosion, thereby improving the performance of the refractory material.

[0109] According to the data in Table 1, the refractory material prepared in Comparative Example 5 showed a significant decrease in residual strength retention, a smaller oxide layer thickness, and a certain degree of reduction in erosion rate. The difference between Comparative Example 5 and Example 1 is that tungsten carbide was not used in the interface isolation material. This proves that the presence of tungsten carbide can ensure the stability of the outer liquid phase isolation layer to a certain extent, thereby indirectly improving the refractory performance of the refractory material, maintaining the isolation stability of magnesium phosphate and aluminum phosphate ion phases, and thus improving the erosion resistance to manganese-iron molten iron.

[0110] According to the data in Table 1, the refractory material prepared in Comparative Example 6 showed very little decrease in residual strength retention, a lower oxide layer thickness, and a certain degree of decrease in erosion rate. The difference between Comparative Example 6 and Example 1 is that a nitrogen-containing electrolyte was not used when the tantalum powder was electrolyzed. This proves that the nitriding treatment method can ensure that the amount of tantalum nitride generated is sufficient, and can fill and repair the tiny gaps that are not completely covered, thereby isolating the erosion of manganese iron molten iron and improving the performance of the refractory material.

[0111] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a refractory material resistant to manganese-iron corrosion, characterized in that, The material comprises a permanent layer and a working layer, wherein the specific preparation steps of the working layer are as follows: S1. Construction of the microporous structure of ASC bricks: ASC bricks are heated to 650-750℃ for heat treatment in an oxygen atmosphere for 2-4 hours with an atmosphere introduction rate of 5-10 L / min, and then cooled to obtain a porous surface material. S2. Preparation of the supported porous matrix: The surface porous matrix is ​​placed in an aqueous solution of zirconium oxychloride and ammonia is added dropwise to form a precipitate. Then the surface porous matrix is ​​taken out and placed in an ethylenediamine solution of barium salt. After stirring, it is heated and reacted at 160-220℃ for 12-36 hours. After washing, the supported porous matrix is ​​obtained. The loaded porous matrix is ​​then modified, and the specific modification steps are as follows: Tantalum powder was coated onto the surface of a supported porous substrate, then heat-treated at high temperature in an ammonia atmosphere, and then placed in a nitrogen-containing electrolyte for electrolytic treatment for 0.5-2 hours with a pulse current of 10-100 kHz to obtain a modified filler. S3. Preparation of the isolation material: Weigh magnesium phosphate, aluminum phosphate and tungsten carbide and mix them to obtain the isolation material. Press the isolation material onto the outside of the modified filler by cold isostatic pressing to form a rough blank. Heat treat the rough blank to form the isolation material. The insulating material is composed of magnesium phosphate, aluminum phosphate and tungsten carbide, with a mass ratio of magnesium phosphate, aluminum phosphate and tungsten carbide of 4-6:4-6:8-12.

2. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, The ASC brick is made by sintering a mixture of 45-65 parts corundum, 15-25 parts silicon carbide, 10-20 parts graphite, 8-12 parts aluminum dihydrogen phosphate, and 2-3 parts pure aluminum powder by weight.

3. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 2, characterized in that, The graphite has a particle size of 0.125-0.500 mm, of which 60% is graphite with a particle size of 0.125-0.300 mm and 40% is graphite with a particle size of 0.300 mm-0.500 mm.

4. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, The permanent layer is composed of 60-70 parts by weight of alumina, 5-10 parts by weight of aluminum silicate, 5-8 parts by weight of silicon powder, 15-20 parts by weight of silicon dioxide, and 0.1-1 parts by weight of sodium tripolyphosphate.

5. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, In step S1, the cooling is performed at a uniform rate of 50°C / h.

6. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, The ratio of zirconium oxychloride to barium salt is 1:1, and the concentrations of both zirconium oxychloride and barium salt are 5-50 mmol / mL, while the concentration of ammonia water is 30 wt%.

7. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, The high-temperature treatment in the ammonia atmosphere in step S2 is at a temperature of 800-1000℃.

8. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, In step S2, the nitrogen-containing electrolyte is an organic-inorganic composite electrolyte. The organic substance is urea, ethylenediamine, or melamine, and the inorganic material is ammonium nitrate, potassium nitrate, ammonium sulfate, or ammonium phosphate.

9. The method for preparing a refractory material resistant to manganese-iron corrosion according to claim 1, characterized in that, In step S3, the pressure of cold isostatic pressing of the isolation material is 300-600 MPa, the time of cold isostatic pressing is 5-10 min, the heat treatment temperature is 1200-1350℃, the heat treatment time is 3-12 h, and Co or Ni is added as a sintering binder, with the amount of sintering binder used being 2-4%.

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