Acidic dry material for intermediate frequency furnace based on micronized raw materials and preparation method of acidic dry material

Abstract

The invention belongs to the field of acidic dry materials, and particularly provides a micronized raw material-based acidic dry material for an intermediate frequency furnace and a preparation method of the micronized raw material-based acidic dry material. The invention discloses a micronized raw material-based acidic dry material for an intermediate frequency furnace. The micronized raw material-based acidic dry material comprises the following raw materials in parts by mass: 70-80 parts of silica aggregate, 20-25 parts of micronized silicon powder and 0.7-0.85 part of a sintering agent, the micronized silicon powder is prepared by the following steps: S1, taking small-grain silica, drying, and coarsely grinding to obtain a coarsely ground material; and S2, adding high-purity silicon dioxide powder and nano zirconium oxide into the coarse grinding material, uniformly mixing, and continuously grinding to obtain the high-purity silicon dioxide nano zirconium oxide grinding material. The prepared acidic dry material for the intermediate frequency furnace based on the micronized raw materials has the advantages of being good in sintering state, excellent in high temperature resistance and resistant to corrosion.

Description

Technical Field

[0001] The present application belongs to the technical field of acidic dry materials, and in particular relates to an acidic dry material for a medium frequency furnace based on micronized raw materials and a preparation method thereof. Background Art

[0002] In modern industrial production, melting equipment plays a key role in the development of numerous industries. Medium-frequency furnaces, with their advantages of rapid heating, high melting efficiency, and precise temperature control, hold a prominent position in the metal melting field. For example, in the steel industry, they are used for melting specialty steels and alloy steels, enabling precise adjustment of molten steel composition to meet the quality requirements of different steel grades. In the nonferrous metals industry, such as copper and aluminum, medium-frequency furnaces enable efficient metal melting and refining processes for melting and casting.

[0003] With the development of industry, the performance requirements for medium-frequency furnaces are constantly increasing. They are expected not only to further improve melting efficiency and reduce energy consumption, but also to ensure stable operation of the equipment and reduce downtime for maintenance due to problems such as lining damage. Currently, the material used in the crucible of medium-frequency furnaces is mainly dry ramming material, which comes in three types: acidic, alkaline, and neutral. During use, the material is vibrated and formed in the furnace by ramming, and then the furnace is baked to obtain strength for smelting operations.

[0004] Among them, acidic dry materials have become an important choice for medium frequency furnace linings due to their good resistance to acidic slag corrosion, convenient construction, and short baking time. Traditional acidic dry materials are mainly made of quartz sand and other materials as the main raw materials, and are prepared by adding appropriate binders and additives. However, in actual use, the existing acidic dry materials still have some problems that need to be solved: on the one hand, their thermal shock resistance is insufficient. During the frequent heating and cooling process of the medium frequency furnace, the furnace lining is prone to cracks, resulting in slag penetration, which in turn affects the service life of the furnace lining. On the other hand, their high-temperature strength is limited. Under high-temperature smelting conditions, the furnace lining may soften and deform, reducing the protective effect on the furnace body and increasing safety hazards. These problems limit the application of acidic dry materials under more demanding smelting conditions, and also prompt the industry to continuously explore ways to improve the performance of acidic dry materials.

[0005] To improve the performance of acidic dry materials, micronization of raw materials has become an important research area. This micronization process, based on the theory of micropowders in refractory materials, allows fine particles to pack more densely during sintering, reducing porosity and increasing the material's density. This not only enhances the material's strength but also effectively blocks slag penetration, improving the erosion resistance of the furnace lining. Micronization also accelerates chemical reactions. During the reaction between the binder and the raw materials, finer raw material particles allow for a more complete reaction, forming a more stable and robust binding phase, thereby improving the overall performance of the acidic dry materials.

[0006] However, the micronized raw materials have the following problems: 1. Poor dispersibility; 2. Single erosion resistance. In view of the importance of intermediate frequency furnaces in industrial production and the problems existing in acid dry materials and micronized raw materials, there is an urgent need to develop a new acid dry material for intermediate frequency furnaces. Summary of the Invention

[0007] In view of the above problems, in order to further improve the technical defects of micronized raw materials and enhance the overall performance of acid dry materials, the present application provides an acid dry material for intermediate frequency furnaces based on micronized raw materials and a preparation method thereof.

[0008] The present application first provides a preparation method of an acid dry material for intermediate frequency furnaces based on micronized raw materials, including the following raw materials in parts by mass: 70-80 parts of silica aggregate, 20-25 parts of micronized silicon powder, and 0.7-0.85 parts of sintering agent; the micronized silicon powder is prepared by the following steps: S1: Take small-grained silica, dry it and first perform rough grinding to obtain rough ground material; S2: Add high-purity silica powder and nano-zirconia to the rough ground material, mix evenly, and continue grinding to obtain it.

[0009] Further, in the step S1, the grain size of the small-grained silica is less than 50 μm; And / or, in the step S1, the average particle size of the rough ground material is 150-300 μm; And / or, in the step S1, the content of silica in the small-grained silica is greater than 99.8%;

[0010] Further, in the step S2, the mass ratio of the rough ground material, high-purity silica powder, and nano-zirconia is 1:(0.1-0.15):(0.005-0.01); And / or, in the step S2, the average particle size of the high-purity silica powder is 5-10 μm; And / or, in the step S2, the purity of the high-purity silica powder is greater than 99.95%; And / or, in the step S2, the average particle size of the nano-zirconia is 50-100 nm; And / or, in the step S2, the average particle size of the micronized silicon powder prepared after grinding is less than 38 μm.

[0011] Further, the sintering agent includes the following raw materials in parts by weight: 20-35 parts of boric anhydride, 5-10 parts of boric acid, and 10-15 parts of modified silicon carbide nanosheets.

[0012] Further, the modified silicon carbide nanosheets are prepared by the following method: 1) Mix deionized water, tetrabutylphosphonium hydroxide, hydroxyethyl cellulose, and N-hydroxysuccinimide evenly to obtain a base liquid; 2) Add silicon carbide and amino-modified graphene to the base liquid. After dispersing evenly, ball mill at a speed of 200 - 350 rpm / min for 1 - 1.5 h to obtain an intermediate liquid; 3) Take the intermediate liquid for vacuum degassing, then dry the obtained solid material, crush and grind it. After grinding, press to obtain a green body, and then sinter, crush, and ball mill the green body to obtain the product.

[0013] Further, in the step 1), the content of tetrabutylphosphonium hydroxide in the base liquid is 2 - 3 wt%; And / or, in the step 1), the content of hydroxyethyl cellulose in the base liquid is 5 - 10 wt%; And / or, in the step 1), the content of N-hydroxysuccinimide in the base liquid is 0.2 - 0.25 wt%.

[0014] Further, in the step 2), the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene is (100 - 150) mL : (65 - 100) g : (15 - 20) g; And / or, in the step 2), the average particle size of silicon carbide is 750 - 900 nm; And / or, in the step 2), the amino-modified graphene is amino acid-modified graphene.

[0015] Further, in the step 3), an infiltration liquid is sprayed during the grinding process. The infiltration liquid includes deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder; the spraying amount of the infiltration liquid is 1.5 - 2% of the mass of silicon carbide.

[0016] Further, in the infiltration liquid, the mass ratio of deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder is 1 : (0.05 - 0.08) : (0.1 - 0.2) : (0.5 - 0.65).

[0017] This application also provides a preparation method of an acidic dry material for intermediate frequency furnace based on micronized raw materials, including the following steps: Weigh silica aggregate, micronized silicon powder, and sintering agent in proportion and mix evenly.

[0018] Compared with the prior art, this application has the following beneficial effects: 1. The micronized silicon powder obtained by introducing a new process in this application regulates the phase change speed during the heating process of the acidic dry ramming mix, strengthens the bonding, reduces the probability of aggregate cracking, etc., improves the sintering performance of the furnace lining and the slag penetration resistance, and obtains a new type of acidic dry ramming mix with excellent physical properties. The performance can reach SiO2 ≥ 97%, bulk density ≥ 2.0 g / cm 3, the linear change is ≤ 7.8% at 1550°C for 3 hours, and the compressive strength is ≥ 10 MPa at 1550°C. In terms of actual applications, when smelting ductile iron, the lining life of the intermediate frequency furnace is ≥ 250 furnaces; when smelting plain carbon steel, the lining life of the intermediate frequency furnace is ≥ 40 furnaces.

[0019] 2. In this application, although the added micro - refined silicon powder has high reactivity, it has poor dispersion performance, single anti - corrosion effect, large expansion, and is prone to cracking at high temperatures. To address this, the applicant introduced a multi - component compound sintering agent based on boric anhydride and boric acid, and added modified silicon carbide nanosheets, which can form a three - dimensional interlocking structure within the sintering layer, playing a very good role in suppressing pull - out stress and crack deflection, dissipating the energy generated by the high - low temperature cyclic impact of the furnace lining, playing a very good role in strengthening and toughening, improving the slag penetration and erosion resistance and anti - cracking performance of the furnace lining. The linear change of the sample after firing is ≤ 5%, and the compressive strength after firing is ≥ 10 MPa.

[0020] 3. During the preparation of the modified silicon carbide nanosheets in this application, firstly, the base liquid can provide a stable physical and chemical environment for silicon carbide and amino - modified graphene, enabling the two to be fully and uniformly dispersed and fused; secondly, during the drying process, the driving force generated by the evaporation of water molecules can be balanced by the base liquid, improving the orientation degree of silicon carbide and amino - modified graphite, contributing to the formation of a bridge - connection structure between silicon carbide and amino - modified graphene, with stronger interfacial bonding force between the interlayer components, inhibiting the transformation of the system from a layered structure to a porous structure; thirdly, during the sintering process, the sheet - layer structure state can be improved through mass transfer, enhancing the mechanical stability of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the compressive strength test data of the samples of Examples 1 - 3 and Control Group 1 of this application; Figure 2 It is a schematic diagram of the XRD analysis of the fired product phase of the sample of Example 2 of this application; Figure 3 It is a schematic diagram of the XRD analysis of the fired product phase of the sample of Example 3 of this application; Figure 4 It is a schematic diagram of the anti - molten slag erosion and penetration test of the samples of Examples 1 - 3 and Control Group 1 of this application; Figure 5 It is a schematic diagram of the SEM test of the sample of Control Group 1 of this application.

[0022] Figure 6 It is a schematic diagram of the SEM test of the sample of Example 2 of this application.

[0023] [[ID=3l]] Figure 7 It is a schematic diagram of the SEM test of the sample of Example 3 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] After extensive experimental research, the present application provides an acidic dry material for a medium frequency furnace based on micronized raw materials, comprising the following raw materials by weight: 70-80 parts of silica aggregate, 20-25 parts of micronized silicon powder, and 0.7-0.85 parts of a sintering agent; the micronized silicon powder is prepared by the following steps: S1: Take small-grain silica, dry it, and then coarsely grind it to obtain coarse abrasive; S2: Add high-purity silicon dioxide powder and nano-zirconium oxide to the coarse abrasive, mix evenly, and continue grinding.

[0026] Furthermore, in step S1, the grain size of the small-grain silica is less than 50 μm; And / or, in step S1, the average particle size of the coarse abrasive is 150-300 μm; And / or, in step S1, the silicon dioxide content in the small-grain silica is greater than 99.8%.

[0027] In some specific embodiments, under normal circumstances, the acidic dry material for the medium frequency furnace based on micronized raw materials includes the following raw materials in parts by weight: 80 parts of silica aggregate, 20 parts of micronized silicon powder, and 0.8 parts of sintering agent, which can obtain better experimental results.

[0028] In some specific embodiments, in step S1, the average particle size of the coarse abrasive can be 150 μm, 200 μm, 250 μm, or 30 μm. Generally, a better experimental effect can be obtained when the average particle size of the coarse abrasive is 200 μm.

[0029] In some specific embodiments, in step S1, the small-grain silica is made from high-quality silica. In the embodiment of the present application, the small-grain silica is made from high-quality silica produced in Gucheng County, Xiangyang City.

[0030] Furthermore, in step S2, the mass ratio of the coarse abrasive, high-purity silica powder, and nano-zirconium oxide is 1:(0.1-0.15):(0.005-0.01); And / or, in step S2, the average particle size of the high-purity silicon dioxide powder is 5-10 μm; And / or, in step S2, the purity of the high-purity silicon dioxide powder is greater than 99.95%; And / or, in the step S2, the average particle size of the nano-zirconia is 50-100 nm; And / or, in the step S2, the average particle size of the micronized silica powder prepared after grinding is less than 38 μm.

[0031] In some specific embodiments, in the step S2, the mass ratio of the coarse abrasive, the high-purity silica powder, and the nano-zirconia can be 1:0.1:0.005, 1:0.12:0.005, 1:0.13:0.005, 1:0.15:0.005, 1:0.1:0.006, 1:0.1:0.007, 1:0.1:0.008, 1:0.1:0.009, 1:0.1:0.01, 1:0.12:0.006, 1:0.12:0.007, 1:0.12:0.008, 1:0.12:0.009, 1:0.12:0.01, 1:0.15:0.006, 1:0.15:0.007, 1:0.15:0.008, 1:0.15:0.009, 1:0.15:0.01. Usually, when the mass ratio of the coarse abrasive, the high-purity silica powder, and the nano-zirconia is 1:0.15:0.005, better experimental results can be obtained.

[0032] More preferably, usually, in the step S2, when the average particle size of the high-purity silica powder is 10 μm and the average particle size of the nano-zirconia is 50 nm, the experimental results are better.

[0033] Furthermore, the sintering agent includes the following raw materials in parts by weight: 20-35 parts of boric anhydride, 5-10 parts of boric acid, and 10-15 parts of modified silicon carbide nanosheets.

[0034] Furthermore, the modified silicon carbide nanosheets are prepared by the following method: 1) Mix deionized water, tetrabutylphosphonium hydroxide, hydroxyethyl cellulose, and N-hydroxysuccinimide evenly to prepare a base liquid; 2) Add silicon carbide and amino-modified graphene to the base liquid, disperse evenly, and then ball-mill at a speed of 200-350 rpm / min for 1-1.5 h to obtain an intermediate liquid; 3) Take the intermediate liquid for vacuum degassing, then dry, crush and grind the obtained solid material, press the ground material to obtain a green body, and sinter, crush and ball-mill the green body to obtain the product.

[0035] Furthermore, in the step 1), the content of tetrabutylphosphonium hydroxide in the base liquid is 2-3 wt%; And / or, in the step 1), the content of hydroxyethyl cellulose in the base liquid is 5-10 wt%; And / or, in step 1), the content of N-hydroxysuccinimide in the base liquid is 0.2-0.25 wt%.

[0036] In some specific embodiments, in step 1), the content of tetrabutylphosphonium hydroxide in the base liquid can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%. Usually, when the content of tetrabutylphosphonium hydroxide in the base liquid is 2.8%, better experimental results can be obtained.

[0037] In some specific embodiments, in step 1), the content of hydroxyethyl cellulose in the base liquid can be 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%. Usually, when the content of hydroxyethyl cellulose in the base liquid is 8.5%, the experimental effect is the best.

[0038] In some specific embodiments, in step 1), the content of N-hydroxysuccinimide in the base liquid can be 0.2 wt%, 0.21 wt%, 0.22 wt%, 0.23 wt%, 0.24 wt%, 0.25 wt%. Usually, when the content of N-hydroxysuccinimide in the base liquid is 0.25 wt%, a better effect can be achieved.

[0039] Further, in step 2), the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene is (100-150) mL: (65-100) g: (15-20) g; And / or, in step 2), the average particle size of silicon carbide is 750-900 nm; And / or, in step 2), the amino-modified graphene is amino acid-modified graphene.

[0040] In some specific embodiments, in step 2), the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene can be 100 mL: 65 g: 15 g, 120 mL: 65 g: 15 g, 150 mL: 65 g: 15 g, 120 mL: 80 g: 15 g, 150 mL: 80 g: 15 g, 120 mL: 65 g: 17.5 g, 120 mL: 65 g: 20 g, 150 mL: 65 g: 17.5 g, 150 mL: 65 g: 20 g, 120 mL: 100 g: 15 g, 120 mL: 100 g: 17.5 g, 120 mL: 100 g: 20 g, 150 mL: 100 g: 15 g, 150 mL: 100 g: 17.5 g, 150 mL: 100 g: 20 g, 150 mL: 80 g: 15 g. Usually, when the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene is 150 mL: 100 g: 15 g, better experimental results can be obtained. More preferably, the average particle size of silicon carbide is 800 nm.

[0041] In some specific embodiments, the amino acid-modified graphene can be L-hydroxyproline-modified graphene, aspartic acid-modified graphene, or tyrosine-modified graphene. Usually, better experimental results can be obtained when the amino acid-modified graphene is aspartic acid-modified graphene.

[0042] Further, in step 3), a penetrant is sprayed during the grinding process. The penetrant includes deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder; the spraying amount of the penetrant is 1.5 - 2% of the mass of silicon carbide.

[0043] Further, in the penetrant, the mass ratio of deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder is 1: (0.05 - 0.08): (0.1 - 0.2): (0.5 - 0.65). Usually, when the mass ratio of deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder is 1: 0.05: 0.15: 0.55, better experimental results can be obtained.

[0044] Further, the modified yttrium powder is prepared by the following steps: Ⅰ. Add 100 mL of N,N-dimethylformamide and 2 g of terephthalic acid into a beaker to prepare a mixed solution for use. Ⅱ. Add 3.5 g of yttrium chloride hexahydrate to the mixed solution, stir rapidly for 30 min, then add 30 g of yttrium powder, heat to 120 °C, keep warm for 3 h, then filter, and wash the filtrate for use. Ⅲ. Prepare 150 mL of 10% sodium methyl silicate solution, add 0.2 g of octadecyl phosphoric acid, then add the washed filtrate, stir for 2 h, then filter and dry to obtain. Example 1

[0045] The acidic dry material for medium-frequency furnace based on micronized raw materials in this embodiment includes the following masses: 80 kg of silica aggregate, 20 kg of micronized silicon powder, and 0.8 kg of sintering agent.

[0046] The micronized silicon powder in this embodiment is prepared by the following steps: S1: Take small-grained silica with a silica content greater than 99.8% and place it in a drying room. Dry it with hot air at a temperature of 200 °C, then pre-crush it into small granular form, and then transfer it to a ball mill for rough grinding. After sieving, obtain the rough grinding material, and the average particle size of the rough grinding material is 200 μm; S2: Add high-purity silica powder and nano-zirconia to the rough grinding material and mix evenly. When the average particle size of the high-purity silica powder is 10 μm and the average particle size of the nano-zirconia is 50 nm, control the mass ratio of the rough grinding material, high-purity silica powder, and nano-zirconia to be 1:0.15:0.005. Continue grinding and sieving to make the average particle size of the micronized silicon powder obtained after grinding less than 38 μm, then it is obtained.

[0047] The sintering agent in this embodiment includes the following raw materials by weight: 632 g of boric anhydride and 168 g of boric acid.

[0048] The preparation method of the acidic dry material for medium-frequency furnace based on micronized raw materials in this embodiment includes the following steps: Weigh the silica aggregate, micronized silicon powder, and sintering agent in proportion and mix them evenly. Example 2

[0049] The acidic dry material for medium-frequency furnace based on micronized raw materials in this embodiment includes the following masses: 80 kg of silica aggregate, 20 kg of micronized silicon powder, and 0.8 kg of sintering agent.

[0050] The micronized silicon powder in this embodiment is prepared by the following steps: S1: Take small-grained silica with a silica content greater than 99.8% and place it in a drying room. Dry it with hot air at a temperature of 200 °C, then pre-crush it into small granular form, and then transfer it to a ball mill for rough grinding. After sieving, obtain the rough grinding material, and the average particle size of the rough grinding material is 200 μm; S2: Add high-purity silica powder and nano-zirconia to the rough grinding material and mix evenly. When the average particle size of the high-purity silica powder is 10 μm and the average particle size of the nano-zirconia is 50 nm, control the mass ratio of the rough grinding material, high-purity silica powder, and nano-zirconia to be 1:0.15:0.005. Continue grinding and sieving to make the average particle size of the micronized silicon powder obtained after grinding less than 38 μm, then it is obtained.

[0051] The sintering agent of this embodiment comprises raw materials with the following weights: 500 g of boric anhydride, 133 g of boric acid, and 167 g of modified silicon carbide nanosheets.

[0052] The modified silicon carbide nanosheets of this embodiment are prepared by the following method: 1) Deionized water, tetrabutylphosphonium hydroxide, hydroxyethyl cellulose, and N-hydroxysuccinimide are added into a stirring kettle and mixed evenly at a speed of 350 rpm to obtain a base liquid; in the base liquid: the content of tetrabutylphosphonium hydroxide is 2.8%, the content of hydroxyethyl cellulose is 8.5%, and the content of N-hydroxysuccinimide is 0.25 wt%. 2) The base liquid is added into a ball mill, then silicon carbide and amino-modified graphene are added. After being dispersed evenly, ball milling is carried out at a speed of 300 rpm / min for 1.5 h to obtain an intermediate liquid; when the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene is 150 mL: 100 g: 15 g; the average particle size of silicon carbide is 800 nm; the amino acid-modified graphene is aspartic acid-modified graphene. 3) The intermediate liquid is taken for vacuum degassing under a vacuum degree of -0.05, and then the solid material obtained by vacuum drying at a temperature of 100 °C is crushed and ground. After grinding, it is put into a stainless steel mold for pressing to obtain a green body. The green body is placed in a muffle furnace and heated to 1250 °C at a heating rate of 10 °C / min for sintering for 3.5 h. After sintering, it is naturally cooled, crushed, and ball milled to obtain the product.

[0053] The preparation method of the acid dry material for intermediate frequency furnace based on micronized raw materials of this embodiment comprises the following steps: Weigh silica aggregate, micronized silicon powder, and sintering agent in proportion and mix them evenly. Example 3

[0054] The acid dry material for intermediate frequency furnace based on micronized raw materials of this embodiment comprises the following masses: 80 kg of silica aggregate, 20 kg of micronized silicon powder, and 0.8 kg of sintering agent.

[0055] The micronized silicon powder of this embodiment is prepared by the method with the following steps: S1: Small-grained silica with a silicon dioxide content greater than 99.8% is placed in a drying room and hot air dried at a temperature of 200 °C, then pre-crushed into small granular shapes, and then transferred to a ball mill for rough grinding. After sieving, rough grinding materials are obtained, and the average particle size of the rough grinding materials is 200 μm. S2: High-purity silica powder and nano-zirconia are added to the rough grinding materials and mixed evenly. When the average particle size of the high-purity silica powder is 10 μm and the average particle size of the nano-zirconia is 50 nm, the mass ratio of the rough grinding materials, high-purity silica powder, and nano-zirconia is controlled to be 1: 0.15: 0.005. Continue grinding and sieving to make the average particle size of the micronized silicon powder prepared after grinding less than 38 μm, then the product is obtained.

[0056] The sintering agent of this embodiment comprises raw materials with the following weights: 453 g of boric anhydride, 121 g of boric acid, and 226 g of modified silicon carbide nanosheets.

[0057] The modified silicon carbide nanosheets of this embodiment are prepared by the following method: 1) Add deionized water, tetrabutylphosphonium hydroxide, hydroxyethyl cellulose, and N-hydroxysuccinimide into a stirring kettle, and mix them evenly at a speed of 350 rpm to obtain a base liquid; in the base liquid: the content of tetrabutylphosphonium hydroxide is 2.8%, the content of hydroxyethyl cellulose is 8.5%, and the content of N-hydroxysuccinimide is 0.25 wt%. 2) Add the base liquid into a ball mill, then add silicon carbide and amino-modified graphene, disperse them evenly, and ball mill at a speed of 300 rpm / min for 1.5 h to obtain an intermediate liquid; when the mass-volume ratio of the base liquid, silicon carbide, and amino-modified graphene is 150 mL:100 g:15 g; the average particle size of silicon carbide is 800 nm; the amino acid-modified graphene is aspartic acid-modified graphene. 3) Take the intermediate liquid to carry out vacuum degassing under a vacuum degree of -0.05, then vacuum dry the obtained solid material at a temperature of 100 °C, crush and grind it. During the grinding process, spray a penetrant. The penetrant is composed of deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder according to a mass ratio of 1:0.05:0.15:0.55. The spraying amount of the penetrant is 1.65% of the mass of silicon carbide. After grinding, put it into a stainless steel mold and press to obtain a green body. Place the green body in a muffle furnace, heat it to 1250 °C at a heating rate of 10 °C / min and sinter for 3.5 h. After sintering, cool it naturally, crush and ball mill to obtain the product.

[0058] The modified yttrium powder of this embodiment is prepared by the following steps: Ⅰ. Add 100 mL of N,N-dimethylformamide and 2 g of terephthalic acid into a beaker to prepare a mixed solution for later use. Ⅱ. Add 3.5 g of yttrium chloride hexahydrate to the mixed solution, quickly stir for 30 min, then add 30 g of yttrium powder, heat to 120 °C, keep it warm for 3 h, then filter, and wash the filtrate for later use. Ⅲ. Prepare 150 mL of 10% methyl sodium silicate solution, add 0.2 g of octadecyl phosphoric acid, then add the washed filtrate, stir for 2 h, then filter and dry to obtain the product.

[0059] The preparation method of the acidic dry material for intermediate frequency furnace based on micronized raw materials in this embodiment comprises the following steps: Weigh silica aggregate, micronized silicon powder, and sintering agent in proportion and mix them evenly.

[0060] Control Group 1 The acid dry material for intermediate frequency furnace in this control group includes the following masses: 100 kg of quartz sand and 0.8 kg of sintering agent.

[0061] The particle size and gradation of the quartz sand are as follows: 4 - 2 mm, 12.6%; 2 - 1 mm, 13.8%; 1 - 0.2 mm, 45.3%; 0.2 - 0.06 mm, 19.7%; ≤0.06 mm, 8.6%.

[0062] The sintering agent in this control group includes raw materials with the following weights: 632 g of boric anhydride and 168 g of boric acid.

[0063] The preparation method of the acid dry material for intermediate frequency furnace based on micronized raw materials in this control group includes the following steps: Weigh the quartz sand and sintering agent according to the proportion and mix them evenly.

[0064] Performance testing 1. Take the acid dry materials for intermediate frequency furnace based on micronized raw materials in Examples 1 - 3 and the acid dry material for intermediate frequency furnace in Control Group 1. Adopt the dry pressing forming method with a forming pressure of 150 MPa and a holding pressure time of 1 min to make a cylindrical blank with a diameter of Φ50 mm. Then, keep it warm and sinter for 3 h at 1150 °C and 1550 °C respectively to make specimens, and then conduct compressive strength tests on a universal mechanical testing machine according to GB / T 5072 - 2008. The results are as Figure 1 shown. And analyze the phase composition of the specimens after sintering in Example 2 and Example 3. The results are as Figure 2 and Figure 3 shown. It can be seen that more cristobalite is generated in the specimen phase of Example 3, and the phase change state is better.

[0065] 2. Take the acid dry materials for intermediate frequency furnace based on micronized raw materials in Examples 1 - 3 and the acid dry material for intermediate frequency furnace in Control Group 1. Pour the materials into the mold and press - form them under a pressure of 76 MPa to obtain a crucible specimen with a size of Φ\(50×50\) mm and small holes (Φ\(18×24\) mm) at the top. The formed green crucible blank is placed in an oven and dried at 110 °C, and then conduct an anti - slag erosion and penetration experiment on the material by the static crucible method according to the standard of GB / T 8931 - 2007, and observe the erosion state of the specimen surface. The test results are as Figure 4 shown. It can be seen that after adding modified silicon carbide nanosheets in Example 2 and Example 3 of this application, the anti - erosion ability of the specimen can be effectively improved.

[0066] 3. Take the specimens of Control Group 1, Example 2 and Example 3, conduct brittle fracture, grinding, and then perform scanning electron microscope tests. The test results are as Figure 5 , Figure 6 and Figure 7 shown, where Figure 5 is Control Group 1.Figure 6 For Example 2, Figure 7 For Example 3, it can be seen that the sintered structure of Control Group 1 is loose and there are many pores between the aggregate particles. The sintered structures of Example 2 and Example 3 are relatively delicate and uniform, and the compatibility between the modified silicon carbide nanosheets and the matrix is good. Moreover, in the preparation process of the modified silicon carbide nanosheets in Example 3, a penetrating liquid is added, which can improve the sintered structure of the specimen, the compatibility between various components is better, the structure is more delicate, and the interfacial bonding force is stronger.

[0067] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present invention.

Claims

1. An acidic dry material for intermediate frequency furnace based on micronized raw materials, characterized in that: It comprises raw materials in the following parts by mass: 70 - 80 parts of silica aggregate, 20 - 25 parts of micronized silica powder, and 0.7 - 0.85 part of sintering agent; the micronized silica powder is prepared by the following method: S1: Take small - grained silica, dry it and then carry out coarse grinding to obtain coarse abrasive; S2: Add high - purity silica powder and nano - zirconia into the coarse abrasive, mix them evenly, and continue grinding to obtain it; The sintering agent comprises raw materials in the following parts by weight: 20 - 35 parts of boric anhydride, 5 - 10 parts of boric acid, and 10 - 15 parts of modified silicon carbide nanosheets; The modified silicon carbide nanosheets are made by the following method: 1) Mix deionized water, tetrabutylphosphonium hydroxide, hydroxyethyl cellulose, and N - hydroxysuccinimide evenly to prepare a base liquid; 2) Add silicon carbide and amino - modified graphene into the base liquid, disperse them evenly and then ball - mill at a speed of 200 - 350 rpm / min for 1 - 1.5 h to obtain an intermediate liquid; 3) Take the intermediate liquid for vacuum degassing, then dry it, crush and grind the obtained solid material, press the ground material to obtain a green body, sinter the green body and then crush and ball - mill it to obtain.

2. The acid dry material for intermediate frequency furnace based on micronized raw materials according to claim 1, characterized in that: In the step S1, the grain size of the small - grained silica is less than 50 μm; And / or, in the step S1, the average particle size of the coarse abrasive is 150 - 300 μm; And / or, in the step S1, the content of silicon dioxide in the small - grained silica is greater than 99.8%; 3. The acid dry material for medium-frequency furnace based on micronized raw materials according to claim 1, wherein: In the step S2, the mass ratio of the coarse abrasive, high - purity silica powder, and nano - zirconia is 1:(0.1 - 0.15):(0.005 - 0.01); And / or, in the step S2, the average particle size of the high - purity silica powder is 5 - 10 μm; And / or, in the step S2, the purity of the high - purity silica powder is greater than 99.95%; And / or, in the step S2, the average particle size of the nano - zirconia is 50 - 100 nm; And / or, in the step S2, the average particle size of the micronized silica powder prepared after grinding is less than 38 μm.

4. The acid dry material for medium frequency furnace based on micronized raw materials according to claim 1, characterized in that: In the step 1), the content of tetrabutylphosphonium hydroxide in the base liquid is 2 - 3 wt%; And / or, in the step 1), the content of hydroxyethyl cellulose in the base liquid is 5 - 10 wt%; And / or, in the step 1), the content of N - hydroxysuccinimide in the base liquid is 0.2 - 0.25 wt%.

5. The acidic dry material for intermediate frequency furnace based on micronized raw materials according to claim 1, characterized in that: In the step 2), the mass - volume ratio of the base liquid, silicon carbide, and amino - modified graphene is (100 - 150) mL:(65 - 100) g:(15 - 20) g; And / or, in the step 2), the average particle size of the silicon carbide is 750 - 900 nm; And / or, in the step 2), the amino - modified graphene is amino - acid - modified graphene.

6. The acid dry material for medium frequency furnace based on micronized raw materials according to claim 1, characterized in that: In the step 3), a penetrant is sprayed during the grinding process. The penetrant comprises deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder; the spraying amount of the penetrant is 1.5 - 2% of the mass of the silicon carbide.

7. The acid dry material for medium frequency furnace based on micronized raw materials according to claim 6, characterized in that: In the penetrant, the mass ratio of deionized water, ammonium carbonate, hydroxytyrosol, and modified yttrium powder is 1:(0.05 - 0.08):(0.1 - 0.2):(0.5 - 0.65).

8. A preparation method of an acid dry material for an intermediate frequency furnace based on micronized raw materials as described in claim 1, characterized in that: It includes the following steps: Weigh the silica aggregate, micronized silica powder, and sintering agent in proportion and mix them evenly.

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