Environment-friendly high-performance anhydrous stemming for iron-making blast furnace and preparation method thereof

Abstract

This invention discloses an environmentally friendly, high-performance anhydrous taphole clay for blast furnaces and its preparation method, belonging to the field of refractory materials technology. It addresses the problems of existing anhydrous taphole clay, which relies on binder modification and requires improvements in bonding strength, high-temperature resistance, and environmental friendliness. The invention comprises, by weight, 30-40 parts bauxite, 5-10 parts silicon nitride micropowder, 20-30 parts silicon nitride, 3-5 parts silicon nitride iron micropowder, 6-10 parts composite inorganic micropowder, 5-10 parts modified coal tar, 1-2 parts carbon black, 3-5 parts carbon nanotubes, and 5-10 parts modified binder. This invention uses surfactants to modify coal tar, improving its combustibility, and also uses diketoxime and nano-lignin powder to modify polyurethane to prepare a modified binder with strong adhesion, environmental friendliness, and high-temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to an environmentally friendly, high-performance anhydrous taphole clay for blast furnaces and its preparation method. Background Technology

[0002] Blast furnace taphole mud is a refractory material used to seal the taphole. It is a key refractory material to ensure the smooth operation of the taphole in front of the furnace. It has the functions of stabilizing the discharge of molten iron and slag formed inside the hearth, extending the taphole depth, and protecting the hearth sidewalls. As an unshaped refractory material, blast furnace taphole mud is used in industry to seal the blast furnace taphole and is an important part of ensuring the smooth operation of the blast furnace.

[0003] Blast furnace taphole clay is a refractory material used to seal the taphole of a blast furnace during the ironmaking process. It is applied using specialized equipment in the metallurgical industry – a clay gun – which forces it into the taphole under pressure. Depending on the binder, taphole clay can be divided into aqueous taphole clay and anhydrous taphole clay. Anhydrous taphole clay uses organic materials such as tar and resin as binders. In large and medium-sized blast furnaces with high top pressure and high intensification of smelting processes, anhydrous taphole clay is often used to meet the needs of safe, stable, and high-yield blast furnaces. As blast furnaces continue to develop towards larger sizes, anhydrous taphole clay, with its superior comprehensive properties including high Marshall value, low linear shrinkage, and excellent high-temperature flexural strength, has a wider range of applications.

[0004] Anhydrous taphole clay is made primarily from high-alumina bauxite clinker, white clay, carbon black, silicon carbide, asphalt, and coke powder, and is compounded with binders. Traditional anhydrous taphole clay uses tar, anthracene oil, and asphalt as binders. The polycyclic aromatic hydrocarbons in these binders volatilize during heating, forming a pungent, acidic odor and yellow fumes containing a large number of carcinogens. Not only does it produce severe smoke, but it also poses a great threat to the environment and the health of workers during actual use. Preparing green and environmentally friendly binders with excellent adhesion properties is a technical problem that urgently needs to be solved.

[0005] Patent application CN107056260A discloses an environmentally friendly anhydrous taphole mud for sealing the taphole of an ironmaking blast furnace and its preparation method. The mud includes bauxite, recycled silica-molybdenum bricks, coke powder, silica, clay, mica, silicon carbide, silicon nitride ferronitride, pitch, recycled magnesia-carbon bricks, coal tar, and resin. The process involves uniformly mixing and extruding the above raw materials to obtain a cylindrical product, i.e., the environmentally friendly anhydrous taphole mud. The resin used is specifically phenolic resin, which improves the high-temperature resistance and environmental friendliness of the binder. However, phenolic resin has relatively few polar groups, resulting in lower bonding strength between the binder and other materials. Furthermore, improving the Massart value and linear shrinkage rate of the anhydrous taphole mud are also urgent technical problems that need to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly, high-performance anhydrous taphole clay for blast furnaces and its preparation method, in order to solve the problems in the existing anhydrous taphole clay suitable for large and medium-sized blast furnaces that lacks comprehensive performance such as high Marshall value, low linear shrinkage rate, and excellent high-temperature flexural strength, as well as the technical problems of how to improve the adhesiveness, green environmental protection characteristics, and high-temperature resistance of the binder used in the anhydrous taphole clay.

[0007] The objective of this invention can be achieved through the following technical solution: an environmentally friendly, high-performance anhydrous taphole clay for blast furnaces, comprising, by weight, 30-40 parts of bauxite, 5-10 parts of silicon nitride micro powder, 20-30 parts of silicon nitride, 3-5 parts of silicon nitride iron micro powder, 6-10 parts of composite inorganic micro powder, 5-10 parts of modified coal tar, 1-2 parts of carbon black, 3-5 parts of carbon nanotubes, and 5-10 parts of modified binder.

[0008] The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared by this invention uses bauxite and silicon nitride as aggregates.

[0009] Furthermore, the method for preparing the modified coal tar includes the following steps:

[0010] A1, N,N-dimethyl-N-octadecyloxymethylene betaine and hexadecylpropylhydroxysulfonyl betaine were mixed evenly in a mass ratio of 1:1 to obtain a composite modifier.

[0011] A2. Coal tar, water and composite modifier are mixed and stirred until uniform, and then allowed to stand naturally for 24 hours to obtain modified coal tar.

[0012] Furthermore, in step A2, the ratio of coal tar, water, and composite modifier is 80g:10-20g:5-10g; the mixing speed is 100-200r / min, and the mixing time is 10-15min.

[0013] Furthermore, the method for preparing the modified adhesive includes the following steps:

[0014] B1, ethylene glycol, dibutyltin dilaurate, dimethylamide, toluene 2,6-diisocyanate and butanedione oxime are mixed evenly and reacted at 60-70℃ for 1-2 hours to obtain the prepolymer;

[0015] A prepolymer was prepared by reacting dibutyltin dilaurate as a catalyst and dimethylformamide as an organic solvent with butanedione oxime, ethylene glycol and toluene 2,6-diisocyanate as monomers.

[0016] The reaction formula for preparing the prepolymer by reacting ethylene glycol, toluene 2,6-diisocyanate, and butanedione oxime is as follows:

[0017]

[0018] B2. Mix lignin and tetrahydrofuran evenly to obtain a lignin solution; filter the lignin solution with a filter with a pore size of 0.2-0.3 μm to obtain a lignin solution after impurity removal; inject the lignin solution after impurity removal into a dialysis bag, dialyze with deionized water for 24 h, and then freeze-dry it to obtain nano-lignin powder.

[0019] B3. Mix the nano-lignin powder and the prepolymer, and continue the reaction at 60-70℃ for 1-2 hours to obtain modified polyurethane; pour the modified polyurethane into a glass plate and let it stand at room temperature for 12 hours to obtain modified adhesive.

[0020] Taking the coniferyl alcohol monomer in nano-lignin powder as an example, the reaction formula for preparing the modified adhesive by reacting it with the prepolymer is as follows:

[0021]

[0022] Further, in step B1, the ratio of ethylene glycol, dibutyltin dilaurate, dimethylamide, toluene 2,6-diisocyanate, and dimethylglyoxime is 30g:0.05-0.1g:30-50mL:130-150g:10-20g; in step B2, the ratio of lignin and tetrahydrofuran is 5-10g:50mL.

[0023] As another aspect of the present invention, a method for preparing environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces includes the following steps:

[0024] S1. Silicon nitride is ground to 100-300 mesh to obtain silicon nitride micro powder; silicon nitride iron is ground to 1-10μm to obtain silicon nitride iron micro powder; alkaline refractory serpentine and siliceous refractory quartz ceramic are mixed in a mass ratio of 1:1 and ground to 200-300 mesh to obtain composite inorganic micro powder.

[0025] S2. Mix bauxite, silicon nitride micro powder, silicon nitride, silicon nitride iron micro powder, quartz ceramics, modified coal tar, carbon black, carbon nanotubes and composite inorganic micro powder evenly to obtain a mixture;

[0026] The bauxite selected in this invention has a particle size of 200-300 mesh, wherein the mass percentage of Al2O3 is >80%.

[0027] S3. Add the mixture to the mixing mill and dry-mill at 55-65℃ for 5-10 minutes. Then add the modified binder and continue milling for 20-30 minutes. Take a sample from the mixing mill and test the Massa value of the sample. When the Massa value of the taphole clay is 0.5-1MPa, discharge the material to obtain taphole clay. The taphole clay is extruded through a taphole clay forming machine to obtain environmentally friendly, high-performance anhydrous taphole clay for iron blast furnaces.

[0028] Furthermore, in step S3, the amount of modified adhesive used is 5-10 parts; the capacity of the clay molding machine is 0.5m³. 3 The total power of the motor's spiral blade shaft is 2.5N, and the motor power is 15-20KW.

[0029] The present invention has the following beneficial effects:

[0030] 1. The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared by this invention comprises a skeleton, reinforcing agents silicon nitride micro powder and silicon nitride iron micro powder, refractory materials serpentine rock and quartz ceramics, carbon-based materials, and modified binders. The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared by this invention uses bauxite and silicon nitride as aggregates; bauxite and silicon nitride together constitute the skeleton of the anhydrous taphole clay, preventing over-sintering of the refractory raw materials and facilitating drilling. Adding a certain amount of silicon nitride micro powder and silicon nitride iron micro powder as reinforcing agents can significantly improve the compressive strength and flexural strength of the prepared anhydrous taphole clay; silicon nitride in silicon nitride iron is chemically bonded through strong covalent bonds, resulting in high mechanical strength and hardness, and tending to be stable at high temperatures; the iron in the silicon nitride iron component forms a liquid phase at high temperatures, promoting sintering of the taphole clay; adding a certain amount of silicon nitride and silicon nitride iron micro powder can improve the taphole clay's resistance to slag and iron erosion.

[0031] 2. Serpentine, an alkaline refractory material, is primarily composed of serpentine, with secondary minerals including magnetite, ilmenite, chromite, and residual olivine and pyroxene. At 700℃, serpentine dehydrates to form forsterite and amorphous MgSiO3; at 1000℃, the amorphous MgSiO3 transforms into enstatite. As a calcium-free, magnesium oxide-rich source, serpentine can improve slag desulfurization and alkali removal capabilities. Quartz ceramics, made from fused silica, possess a low coefficient of linear expansion and excellent thermal shock resistance. Furthermore, quartz ceramics react with CaO and Al2O3 in the slag to generate a series of high-melting-point compounds, which slow down the slag erosion rate while increasing slag viscosity, thereby improving the slag resistance of the refractory material.

[0032] 3. Carbon-based materials include modified coal tar, carbon black, and carbon nanotubes. Using coal tar in anhydrous taphole clay can increase its plasticity. During use, coal tar carbonizes at high temperatures to form carbon bonds, improving the anhydrous taphole clay's resistance to slag erosion and molten iron scouring. However, coal tar contains a large number of impurities and high molecular weight compounds, resulting in slow carbonization and poor combustion. Using a mixture of two amphoteric surfactants as a composite modifier, coal tar and water are mixed. The hydrophilic groups act on water particles, and the lipophilic groups act on oil particles, causing the oil-water mixture to form an emulsion, resulting in modified coal tar. The water in the modified coal tar promotes its overall combustion performance, thereby improving the combustion characteristics of the anhydrous taphole clay. Furthermore, coal tar modified with the composite modifier can further improve its plasticity. After high-temperature calcination, the amount of amorphous carbon and other non-highly graphitized structural materials in carbon nanotubes is reduced, resulting in further purification of the carbon nanotubes. Impurity atoms in the carbon nanotubes are removed, and thermal compression occurs, making the crystals within the carbon nanotubes more ordered, which helps improve the thermal stability and mechanical strength of the carbon nanotubes. Furthermore, all of the aforementioned carbon-based materials possess abundant porosity and volume stability. These materials undergo complex reactions with other components of the clay, forming carbon bonds that stabilize the overall structure.

[0033] 4. To bond the aforementioned skeleton material, reinforcing agent, alkaline refractory material, and carbon-based material together, this invention prepares a high-performance modified adhesive. Specifically, the modified adhesive prepared by this invention is a polyurethane material. Polyurethane has high impact and shear strength, and can form a soft-hard transition layer between different substrates, playing a buffering and shock-absorbing role. Different polyurethane molecular chains all have isocyanate and urethane groups. The presence of these strongly polar functional groups gives the modified adhesive high activity, enabling it to produce high bonding strength with the skeleton material, reinforcing agent, alkaline refractory material, and carbon-based material. However, polyurethane, as a binder, has the disadvantages of being easily hydrolyzed under high temperature and high humidity conditions and having poor heat resistance. When synthesizing the prepolymer using ethylene glycol as the polyol and toluene 2,6-diisocyanate as the polyisocyanate group, butanedione oxime is introduced for modification. The isocyanate group of 2,6-diisocyanate toluene reacts with the oxime group of dimethylglyoxime to yield carbamate oxime groups. The carbamate oxime bond is dynamic, reversibly generating oxime and isocyanate groups at high temperatures. Under high-temperature conditions, the breaking and recombination of dynamic covalent bonds in the polymer chain can induce dynamic adjustments in the polymer network structure, thereby further improving the adhesive properties. Furthermore, the polyurethane prepolymer is modified with nano-lignin. Lignin has high heat resistance and possesses abundant benzene ring structures and 3D network structures. Lignin is mainly polymerized from monomers through β-aryl ether bonds, C / C bonds, etc., and numerous C / C condensation reactions occur between lignin molecules, resulting in a large number of benzene ring structures. Upon heating, lignin with high benzene ring content can form a carbon network structure through carbonization, giving the resulting clay material excellent medium-temperature and high-temperature strength. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for preparing modified coal tar for use in environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, comprising the following steps:

[0037] A1, N,N-dimethyl-N-octadecoxymethylene betaine and hexadecylpropylhydroxysulfonyl betaine were mixed evenly in a mass ratio of 1:1 to prepare a composite modifier.

[0038] N,N-dimethyl-N-octadecoxymethylene betaine and hexadecylpropyl hydroxysulfonate betaine were mixed evenly, and the mixture of the two amphoteric surfactants was used as a composite modifier.

[0039] A2. Add 80g of coal tar and 10g of water to a 250mL round-bottom flask, add 5g of composite modifier to the round-bottom flask, and stir mechanically at 100r / min for 10min to mix evenly. Then let it stand naturally for 24h to obtain modified coal tar.

[0040] Example 2

[0041] This embodiment provides a method for preparing modified coal tar for use in environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, comprising the following steps:

[0042] A1, N,N-dimethyl-N-octadecoxymethylene betaine and hexadecylpropylhydroxysulfonyl betaine were mixed evenly in a mass ratio of 1:1 to prepare a composite modifier.

[0043] A2. Add 80g of coal tar and 15g of water to a 250mL round-bottom flask, add 8g of composite modifier to the round-bottom flask, and stir mechanically at 150r / min for 12min to mix evenly. Then let it stand naturally for 24h to obtain modified coal tar.

[0044] Example 3

[0045] This embodiment provides a method for preparing modified coal tar for use in environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, comprising the following steps:

[0046] A1, N,N-dimethyl-N-octadecoxymethylene betaine and hexadecylpropylhydroxysulfonyl betaine were mixed evenly in a mass ratio of 1:1 to prepare a composite modifier.

[0047] A2. Add 80g of coal tar and 20g of water to a 250mL round-bottom flask, add 10g of composite modifier to the round-bottom flask, and stir mechanically at 200r / min for 15min to mix evenly. Then let it stand naturally for 24h to obtain modified coal tar.

[0048] Example 4

[0049] This embodiment provides a method for preparing a modified binder for environmentally friendly, high-performance anhydrous taphole clay used in ironmaking blast furnaces, comprising the following steps:

[0050] B1. Mix 30g of ethylene glycol, 0.05g of dibutyltin dilaurate, 30mL of dimethylamide, 130g of toluene 2,6-diisocyanate and 10g of dimethylglyoxime into a 250mL short-necked round-bottom flask. A stir bar is placed inside the short-necked round-bottom flask, and an electric heating mantle is placed outside the short-necked round-bottom flask. The temperature of the voltage regulating transformer connected to the electric heating mantle is set to 60℃. React at this temperature at 100r / min for 1h to obtain the prepolymer.

[0051] B2. Mix 5g of lignin and 50mL of tetrahydrofuran evenly to obtain a lignin solution; filter the lignin solution with a filter with a pore size of 0.2μm to obtain a lignin solution after impurity removal; inject the lignin solution after impurity removal into a dialysis bag, dialyze with deionized water for 24h, and then freeze-dry it to obtain nano-lignin powder.

[0052] B3. Then, 5g of nano-lignin powder was transferred to a short-necked round-bottom flask and reacted at 60°C for 1 hour to obtain modified polyurethane. The modified polyurethane was poured into a glass plate and allowed to stand at room temperature for 12 hours to obtain modified adhesive.

[0053] Example 5

[0054] This embodiment provides a method for preparing a modified binder for environmentally friendly, high-performance anhydrous taphole clay used in ironmaking blast furnaces, comprising the following steps:

[0055] B1. Mix 30g of ethylene glycol, 0.08g of dibutyltin dilaurate, 40mL of dimethylamide, 140g of toluene 2,6-diisocyanate and 15g of dimethylglyoxime into a 250mL short-necked round-bottom flask. A stir bar is placed inside the short-necked round-bottom flask, and an electric heating mantle is placed outside the short-necked round-bottom flask. The temperature of the voltage regulating transformer connected to the electric heating mantle is set to 65℃. React at this temperature at 130r / min for 1.3h to obtain the prepolymer.

[0056] B2. Mix 8g of lignin and 50mL of tetrahydrofuran evenly to obtain a lignin solution; filter the lignin solution with a filter with a pore size of 0.2μm to obtain a lignin solution after impurity removal; inject the lignin solution after impurity removal into a dialysis bag, dialyze with deionized water for 24h, and then freeze-dry it to obtain nano-lignin powder.

[0057] B3. Then, 8g of nano-lignin powder was transferred to a short-necked round-bottom flask and reacted at 62℃ for 1.3h to obtain modified polyurethane; the modified polyurethane was poured into a glass plate and allowed to stand at room temperature for 12h to obtain modified adhesive.

[0058] Example 6

[0059] This embodiment provides a method for preparing a modified binder for environmentally friendly, high-performance anhydrous taphole clay used in ironmaking blast furnaces, comprising the following steps:

[0060] B1. Mix 30g of ethylene glycol, 0.1g of dibutyltin dilaurate, 50mL of dimethylamide, 150g of toluene 2,6-diisocyanate and 20g of dimethylglyoxime into a 250mL short-necked round-bottom flask. A stir bar is placed inside the short-necked round-bottom flask, and an electric heating mantle is placed outside the short-necked round-bottom flask. The temperature of the voltage regulating transformer connected to the electric heating mantle is set to 70℃. React at this temperature at 200r / min for 2h to obtain the prepolymer.

[0061] B2. Mix 10g of lignin and 50mL of tetrahydrofuran evenly to obtain a lignin solution; filter the lignin solution with a filter with a pore size of 0.3μm to obtain a lignin solution after impurity removal; inject the lignin solution after impurity removal into a dialysis bag, dialyze with deionized water for 24h, and then freeze-dry it to obtain nano-lignin powder.

[0062] B3. Then, 10g of nano-lignin powder was transferred to a short-necked round-bottom flask and reacted at 70℃ for 2h to obtain modified polyurethane. The modified polyurethane was poured into a glass plate and allowed to stand at room temperature for 12h to obtain modified adhesive.

[0063] Example 7

[0064] This embodiment provides a method for preparing environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, including the following steps:

[0065] S1. Silicon nitride is ground to 100 mesh to obtain silicon nitride micro powder; silicon nitride iron is ground to 1 μm to obtain silicon nitride iron micro powder. Alkaline refractory serpentine and siliceous refractory quartz ceramic are mixed in a mass ratio of 1:1 and ground to 200 mesh to obtain composite inorganic micro powder.

[0066] S2. According to the weight parts, 30 parts of bauxite, 5 parts of silicon nitride micro powder, 20 parts of silicon nitride, 3 parts of silicon nitride iron micro powder, 6 parts of composite inorganic micro powder, 5 parts of modified coal tar prepared in Example 1, 1 part of carbon black and 3 parts of carbon nanotubes are mixed evenly to obtain a mixture.

[0067] S3. Add the mixture to a mixing mill. Set the temperature of the mixing mill to 55℃. Dry-mill for 5 minutes, then add 5 parts of the modified binder prepared in Example 4 and continue milling for 20 minutes. Take a sample from the mixing mill and test its Mashar value. When the Mashar value of the taphole clay is 0.5 MPa, discharge the material to obtain taphole clay. Transfer the taphole clay to the inlet of the YPC taphole clay forming machine and extrude it through the forming tube to obtain a columnar material, which is the environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces. The box capacity of the taphole clay forming machine is 0.5 m³.3 The total power of the motor's spiral blade shaft is 2.5N, and the motor power is 15KW.

[0068] Example 8

[0069] This embodiment provides a method for preparing environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, including the following steps:

[0070] S1. Silicon nitride is ground to 200 mesh to obtain silicon nitride micro powder; silicon nitride iron is ground to 5 μm to obtain silicon nitride iron micro powder. Alkaline refractory serpentine and siliceous refractory quartz ceramic are mixed in a mass ratio of 1:1 and ground to 300 mesh to obtain composite inorganic micro powder.

[0071] S2. According to the weight parts, 35 parts of bauxite, 6 parts of silicon nitride micro powder, 25 parts of silicon nitride, 4 parts of silicon nitride iron micro powder, 8 parts of composite inorganic micro powder, 6 parts of modified coal tar prepared in Example 2, 2 parts of carbon black and 4 parts of carbon nanoparticles are mixed evenly to obtain a mixture.

[0072] S3. Add the mixture to a mixing mill. Set the temperature of the mixing mill to 60℃. Dry-mill for 6 minutes, then add 6 parts of the modified binder prepared in Example 5 and continue milling for 25 minutes. Take a sample from the mixing mill and test its Mashar value. When the Mashar value of the taphole clay is 0.8 MPa, discharge the material to obtain taphole clay. Transfer the taphole clay to the inlet of the YPC taphole clay forming machine and extrude it through the forming tube to obtain a columnar material, which is the environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces. The capacity of the taphole clay forming machine is 0.5 m³. 3 The total power of the motor's spiral blade shaft is 2.5N, and the motor power is 16KW.

[0073] Example 9

[0074] This embodiment provides a method for preparing environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces, including the following steps:

[0075] S1. Silicon nitride is ground to 300 mesh to obtain silicon nitride micro powder; silicon nitride iron is ground to 10 μm to obtain silicon nitride iron micro powder. Alkaline refractory serpentine and siliceous refractory quartz ceramic are mixed in a 1:1 mass ratio and ground to 300 mesh to obtain composite inorganic micro powder.

[0076] S2. According to the weight parts, 40 parts of bauxite, 10 parts of silicon nitride micro powder, 30 parts of silicon nitride, 5 parts of silicon nitride iron micro powder, 10 parts of composite inorganic micro powder, 10 parts of modified coal tar prepared in Example 3, 2 parts of carbon black and 5 parts of carbon nanotubes are mixed evenly to obtain a mixture.

[0077] S3. Add the mixture to a mixing mill. Set the temperature of the mixing mill to 65℃. Dry-mill for 10 minutes, then add 10 parts of the modified binder prepared in Example 6 and continue milling for 30 minutes. Take a sample from the mixing mill and test the Massa value of the sample. When the Massa value of the taphole clay is 1 MPa, discharge the material to obtain taphole clay. Transfer the taphole clay to the inlet of the YPC taphole clay forming machine and extrude it through the forming tube to obtain a long cylindrical strip, which is the environmentally friendly, high-performance anhydrous taphole clay for blast furnaces. The capacity of the taphole clay forming machine is 0.5 m³. 3 The total power of the motor's spiral blade shaft is 2.5N, and the motor power is 20KW.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 9 is that carbon nanotubes were not added during the preparation of the mixture.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 9 is that, in the preparation of the mixture, the modified coal tar was replaced with an equal mass of coal tar.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 9 is that dimethylglyoxime was not added when preparing the mixture and the prepolymer.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 9 is that no composite inorganic micro powder was added when preparing the mixture.

[0086] Performance testing:

[0087] The environmentally friendly, high-performance anhydrous taphole clay prepared in Examples 7-9 and Comparative Examples 1-4 was cut to obtain 500g of cylindrical anhydrous taphole clay as samples.

[0088] 1. The anhydrous tapping mud prepared in Examples 7-9 and Comparative Examples 1-4 was placed in an oven at 50°C and kept warm for 30 minutes, and then the Marshall value was tested in a Marshall value tester.

[0089] 2. According to GB / T5988-2007 "Test Method for Permanent Linear Change of Refractory Materials under Heating", the linear shrinkage rate of the samples after combustion was tested sequentially. The apparent porosity of the samples was determined according to GB / T2997-2015 "Test Method for Bulk Density, Apparent Porosity and True Porosity of Dense-Shaped Refractory Products".

[0090] 3. The high-temperature flexural strength of the specimens was determined according to GB / T3002-2004 "Test Method for High-Temperature Flexural Strength of Refractory Materials". The specific test results are shown in Table 1.

[0091] Table 1 - Performance Test Data of Samples

[0092]

[0093] Data Analysis:

[0094] Comparative analysis of the data in Table 1 shows that the environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared in Examples 7-9 of this invention exhibits strong plasticity, as evidenced by an increase in the Massia value. This indicates that modified coal tar can increase the Massia value of the prepared taphole clay. However, in Comparative Example 2, replacing the modified coal tar with the same mass of coal tar reduced the plasticity of the coal tar itself, resulting in a decrease in the Massia value of the prepared anhydrous taphole clay.

[0095] The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared in Examples 7-9 of this invention has high anti-shrinkage ability and strong supporting force, thereby reducing the linear shrinkage rate of the prepared anhydrous taphole clay; however, the linear shrinkage rate of the anhydrous taphole clay prepared in Comparative Example 4 is significantly increased; serpentine and quartz ceramics themselves have low coefficients of linear expansion, and after removing the composite inorganic micro powder, the coefficient of linear expansion of the anhydrous taphole clay prepared in Examples 7-9 is reduced.

[0096] The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared in Examples 7-9 of this invention has a high apparent porosity, which can be further improved. However, carbon nanotubes were not added to the anhydrous taphole clay prepared in Comparative Example 1; as a carbon-based material, carbon nanotubes have abundant porosity, which can improve the apparent porosity of the anhydrous taphole clay; therefore, the apparent porosity of the anhydrous taphole clay prepared in Comparative Example 1 is reduced.

[0097] The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces prepared in Examples 7-9 of this invention exhibits excellent mechanical properties, particularly a further increase in high-temperature flexural strength. However, in Comparative Example 3, dimethylglyoxime was not added during the preparation of the modified binder, resulting in the absence of dynamically reversible bonds in the prepared binder, which reduced its adhesive performance at high temperatures, manifested as a decrease in high-temperature flexural strength.

[0098] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0099] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0100] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly, high-performance anhydrous taphole clay for blast furnaces, characterized in that, By weight, it includes 30-40 parts of bauxite, 5-10 parts of silicon nitride micro powder, 20-30 parts of silicon nitride, 3-5 parts of silicon nitride iron micro powder, 6-10 parts of composite inorganic micro powder, 5-10 parts of modified coal tar, 1-2 parts of carbon black, 3-5 parts of carbon nanotubes and 5-10 parts of modified binder. The method for preparing the modified adhesive includes the following steps: B1. Ethylene glycol, dibutyltin dilaurate, dimethylformamide, toluene 2,6-diisocyanate, and dimethylglyoxime are mixed evenly and reacted at 60-70℃ for 1-2 hours to obtain a prepolymer. The ratio of ethylene glycol, dibutyltin dilaurate, dimethylformamide, toluene 2,6-diisocyanate, and dimethylglyoxime is 30g:0.05-0.1g:30-50mL:130-150g:10-20g. B2. Mix lignin and tetrahydrofuran evenly to obtain a lignin solution; filter the lignin solution with a filter with a pore size of 0.2-0.3 μm to obtain a purified lignin solution; inject the purified lignin solution into a dialysis bag, dialyze with deionized water for 24 h, and then freeze-dry it to obtain nano-lignin powder, wherein the ratio of lignin to tetrahydrofuran is 5-10 g: 50 mL; B3. Mix the nano-lignin powder and the prepolymer, and continue the reaction at 60-70℃ for 1-2 hours to obtain modified polyurethane; pour the modified polyurethane into a glass plate and let it stand at room temperature for 12 hours to obtain modified adhesive.

2. The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces according to claim 1, characterized in that, The method for preparing the modified coal tar includes the following steps: A1, N,N-dimethyl-N-octadecoxymethylene betaine and hexadecylhydroxypropylsulfobetaine are mixed evenly in a mass ratio of 1:1 to obtain a composite modifier; A2. Coal tar, water and composite modifier are mixed and stirred until uniform, and then allowed to stand naturally for 24 hours to obtain modified coal tar.

3. The environmentally friendly, high-performance anhydrous taphole clay for blast furnaces according to claim 2, characterized in that, In step A2, the ratio of coal tar, water and composite modifier is 80g:10-20g:5-10g; the mixing speed is 100-200r / min and the mixing time is 10-15min.

4. A method for preparing an environmentally friendly, high-performance anhydrous taphole clay for blast furnaces as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Silicon nitride is ground to 100-300 mesh to obtain silicon nitride micro powder; silicon nitride iron is ground to 1-10μm to obtain silicon nitride iron micro powder; alkaline refractory serpentine and siliceous refractory quartz ceramic are mixed in a mass ratio of 1:1 and ground to 200-300 mesh to obtain composite inorganic micro powder. S2. Mix bauxite, silicon nitride micro powder, silicon nitride, silicon nitride iron micro powder, composite inorganic micro powder, modified coal tar, carbon black and carbon nanotubes evenly to obtain a mixture; S3. Add the mixture to the mixing mill and dry-mill at 55-65℃ for 5-10 minutes. Then add the modified binder and continue milling for 20-30 minutes. Take a sample from the mixing mill and test the Massa value of the sample. When the Massa value of the taphole clay is 0.5-1MPa, discharge the material to obtain taphole clay. The taphole clay is extruded through a taphole clay forming machine to obtain environmentally friendly, high-performance anhydrous taphole clay for ironmaking blast furnaces.

5. The method for preparing environmentally friendly, high-performance anhydrous taphole clay for blast furnaces according to claim 4, characterized in that, In step S3, the amount of modified adhesive used is 5-10 parts.

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