Preparation method of high-oxidation-resistance and high-bonding-quality quoin

Abstract

The application belongs to the technical field of refractory materials, and discloses a preparation method of high-oxidation-resistance and high-bonding mortar; through silane coupling agent modification and 80-100 DEG C temperature control stirring process, the problem of easy agglomeration of nano silicon carbide is solved, the dispersion uniformity of the nano silicon carbide in the mortar matrix is improved, and the oxidation resistance is strengthened. The corundum-titanium calcium aluminate-electrically fused magnesia composite aggregate is innovatively adopted, the titanium calcium aluminate special drying pretreatment is matched, the interface bonding force of the aggregate is improved through the precise dry mixing process, and the foundation of high structural stability is laid. The phenolic resin-modified lignin compound system is used to replace the traditional binder, and through water bath pot 60-80 DEG C temperature control stirring, the uniform compounding is realized, the bonding strength and environmental protection are considered, and the harmful volatilization is reduced. The application is applied to the double improvement of the oxidation resistance and bonding performance of the blast furnace mortar, and the service life of the mortar is further improved.

Description

A method for preparing a high-antioxidant and high-binding-strength shotcrete Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a method for preparing a highly antioxidant and highly binding gunning compound. Background Technology

[0002] Taphole clay is the core refractory material for sealing the blast furnace taphole. Its performance directly determines the stability and safety of blast furnace tapping and is crucial for the long-term smooth operation of the blast furnace. With the development of larger and more efficient blast furnaces, the taphole area faces higher temperatures, stronger slag and iron erosion, and more severe oxidation corrosion, which places stringent requirements on the bonding strength and oxidation resistance of the taphole clay.

[0003] In existing technologies, commonly used binders for taphole clay include tar, traditional phenolic resin, and asphalt. While tar-based binders offer some plasticity, they contain the carcinogen benzo[a]pyrene, have poor environmental performance, and have limited coking value at high temperatures. Furthermore, they easily form pores after carbonization, leading to decreased bond strength. Traditional phenolic resins suffer from poor plasticity, rapid hardening, and short shelf life, making them unsuitable for the construction requirements of large blast furnaces. Regarding oxidation resistance, existing taphole clays often improve performance by adding single carbonaceous materials or ordinary silica powder. However, these are prone to carbon oxidation at high temperatures, generating pores that result in a loose structure and significantly reduced erosion resistance, making them unsuitable for long-term high-temperature operations.

[0004] In recent years, environmentally friendly binders and high-efficiency antioxidant additives have become research hotspots. Studies have shown that liquid environmentally friendly resins and modified vegetable oil derivatives can improve the environmental friendliness and plasticity of drilling mud, but when used alone, their high-temperature residual carbon rate is insufficient, limiting the improvement in bonding strength. Boron-containing additives can promote in-situ mullite formation, forming an interwoven network structure to compensate for volume shrinkage, while silicon nitride can react to generate SiC to strengthen the matrix, improving high-temperature strength and oxidation resistance. However, how to scientifically compound these new materials to synergistically improve the bonding strength and oxidation resistance of drilling mud, while also considering environmental friendliness and construction plasticity, remains a pressing technical challenge.

[0005] "A Titanium-Containing Anhydrous Taper Clay for Blast Furnaces and Its Preparation Method" (Xu Yibiao, Wang Xinjie, Ma Yihang, Ding Liangsheng, Li Yawei, Xu Haoran. A Titanium-Containing Anhydrous Taper Clay for Blast Furnaces and Its Preparation Method [P]. 2025.08, CN202511203555.0). The raw materials include titanium corundum, silicon carbide, silicon nitride iron fine powder, titanium dioxide fine powder, vanadium titanium slag fine powder, coke fine powder, elemental silicon fine powder, spherical clay micro powder, aluminum nitrate micro powder, and magnesium allon micro powder. At high temperatures, the elemental silicon fine powder and magnesium allon micro powder in the raw materials will form Si(g), Al(g), and Mg(g) gaseous substances in the taper clay. These substances react with CO and N2 in the environment to generate ceramic whiskers such as SiC, Si3N4, AlN, and MgAl2O4. The generated ceramic whiskers are interspersed and fill the pores of the taper clay, significantly improving the high-temperature strength and volume stability of the taper clay.

[0006] "A Method for Preparing Metal-Toughened Silicon Carbide-Silicon Nitride Slurry Material" (Zuo Liangzhu; Zhao Ming; Tian Shixiu. A Method for Preparing Metal-Toughened Silicon Carbide-Silicon Nitride Slurry Material [P]. 2025.05, CN120329013A). This invention first prepares a modified phenolic resin composition, then dry-kneads refractory aggregates, dispersants, additives, and composite carbon powder, and finally adds the modified phenolic resin composition, mixes, grinds, extrudes, and cuts to obtain the finished metal-toughened silicon carbide-silicon nitride slurry material. Summary of the Invention

[0007] To address the problems of insufficient antioxidant properties, low bonding strength, poor environmental performance, and difficulty in balancing performance in existing tapping clay, this invention provides a tapping clay with high antioxidant properties and high bonding strength, as well as its preparation method. By optimizing the combination of binder system and antioxidant additives, the room temperature bonding strength, high temperature sintering strength, and antioxidant performance of the tapping clay are synergistically improved, while reducing the emission of harmful volatile substances.

[0008] The technical solution adopted in this invention is: a method for preparing a high-antioxidant and high-binding clay is as follows:

[0009] Step 1: Raw material pretreatment: Place nano-silicon carbide with a particle size of 50-100 nm in a high-speed mixer, add silane coupling agent (0.1-0.5% of the mass of nano-silicon carbide), stir at 80-100℃ for 30-50 min for surface modification, cool, and mix evenly with borate at a mass ratio of 7:3 to obtain an antioxidant composite additive for later use; dry calcium titanate particles at 110℃ for 2 h to remove moisture for later use.

[0010] Step 2, Preparation of premix: Add corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia to a mixer; the mass ratio of corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia is 4:3:3, wherein the particle size of corundum particles is 1-3 mm, the particle size of calcium aluminate titanate particles is 0.5-1 mm, and the particle size of fused magnesia is 0.1-0.5 mm; dry mix for 15-35 min to obtain mixed aggregate;

[0011] The following ingredients are added by mass: silicon carbide fine powder, silicon nitride iron fine powder, carbon black, antioxidant composite additive, and dispersant, in the following proportions: silicon carbide 8-20 parts, silicon nitride iron fine powder 2-6 parts, carbon black 1-4 parts, antioxidant composite additive 1.5-5 parts, and dispersant 0.1-0.5 parts. The mixture is then added to a planetary mixer and dry-mixed for 25-45 minutes to achieve uniform dispersion and obtain a mixed matrix.

[0012] Step 3: Preparation of the clay: According to the mass fraction, add 45-65 parts of mixed aggregate to 35-55 parts of mixed matrix, stir for 10-30 minutes, then slowly add 8-16 parts of composite binder, and continue stirring for 30-50 minutes to obtain a uniform clay blank; extrude the blank into clay to obtain a clay with high oxidation resistance and high binding strength.

[0013] In step one, the borate is one or more of borax, magnesium borate, and calcium borate.

[0014] In step two, the dispersant is one or more of polyacrylic acid, polymaleic acid, and polyaspartic acid.

[0015] The composite binder is a mixture of phenolic resin and modified lignin in a mass ratio of 5:3. The phenolic resin is of the low free phenol type, and the modified lignin is one or two of nickel-modified lignin, iron-modified lignin, and lanthanum-modified lignin.

[0016] The composite binder is prepared by placing phenolic resin and modified lignin in a water bath and stirring at 60-80℃ for 20-40 minutes until they are mixed evenly to obtain the composite binder.

[0017] This invention employs a surface-modified nano-silicon carbide and borate composite antioxidant system.

[0018] The silane coupling agent of this invention undergoes a clear chemical modification reaction when added to the surface of nano-silicon carbide (SiC), rather than simple physical adsorption. Due to its small particle size and large specific surface area, nano-SiC spontaneously forms a large number of hydroxyl (-OH) active groups on its surface during preparation or post-treatment. When the silane coupling agent comes into contact with water, it undergoes hydrolysis to generate reactive silanol groups (Si-OH). The Si-OH generated by hydrolysis undergoes a dehydration condensation reaction with the -OH on the surface of nano-SiC to form stable Si-Si covalent bonds, thereby chemically grafting the silane coupling agent onto the SiC surface. Simultaneously, a self-condensation reaction occurs between the Si-OH bound to the SiC surface, forming a dense organosilicon coating layer on the SiC surface. This effectively solves the problem of nano-silicon carbide particle agglomeration and ensures its uniform dispersion in the slurry matrix.

[0019] The modified nano-silicon carbide and calcium titanate have a synergistic effect. Under the high temperature environment of use, calcium titanate reacts with SiO2 to form a liquid phase that coats the particle surface, blocks the pores and wraps the SiC particles. At the same time, TiO2 is transformed into TiCN and distributed at the slag-sludge interface, blocking the slag penetration and oxidation reaction, thus reducing the oxidation weight loss rate of the sludge at 1500℃.

[0020] At high temperatures, calcium aluminate reacts with SiO2 to form a liquid phase. Within the high-temperature service range of 1300~1500℃, calcium aluminate in the gunning mud matrix undergoes a solid-phase reaction with free SiO2 in the system, generating a low-melting-point calcium-silicon-aluminum-titanium composite glass phase. This phase rapidly coats the surface of modified nano-SiC, silicon carbide fine powder, and other particles, forming a dense liquid phase film that blocks the contact channels between the particles and external O2 and slag. It also spontaneously fills the capillary pores and gaps inside the gunning mud matrix, reducing the apparent porosity of the material and constructing a dual densification structure of "particle coating-pore blocking," providing a stable reaction environment for the subsequent in-situ generation of the TiCN phase.

[0021] In this invention, TiO2 originates from the lattice dissociation of calcium aluminate titanate and raw material impurities. Its conversion to TiCN is an in-situ gas-solid reaction, which requires the carbon and nitrogen sources within the clay system and the coating environment of the aforementioned composite liquid phase. The specific reaction pathway is as follows:

[0022] The carbon black in the clay matrix and the pyrolysis products of the modified organic layer on the surface of the modified nano-SiC provide carbon (C) for the reaction; the nitrogen produced by the high-temperature decomposition of silicon nitride iron powder provides nitrogen for the reaction. This process is initiated above 1200℃, and the reaction formula is: Si3N4→3Si+2N2.

[0023] At 1500℃, the free TiO2 from the dissociation of calcium titanate reacts with C and N2 in a gas-solid reaction at the slag-slurry interface to form a solid solution TiCN. Titanium carbide (TiCN) has properties such as high melting point (>350°C), high hardness (Hv3000-4000), excellent corrosion resistance and oxidation resistance.

[0024] The generated TiCN is a nanoscale plate-like crystal (particle size 50~200nm). Due to the interfacial adsorption of the composite liquid phase, it preferentially accumulates at the contact interface between the slag and the slurry, forming a continuous TiCN barrier layer.

[0025] In this invention, borates first melt at 900~1100℃ to form a low-viscosity borosilicate liquid phase, which penetrates into the contact gap between calcium aluminate titanate and SiO2 particles, serving as an ion diffusion channel, reducing the activation energy of the solid-phase reaction, and lowering the formation temperature of the composite liquid phase by 150~200℃. The borates and the calcium-silicon-aluminate-titanium composite liquid are mutually soluble, significantly improving the wetting angle of the liquid phase on the modified nano-SiC particles, ensuring that the liquid phase film uniformly coats the particle surface, and avoiding local "bare particle" oxidation.

[0026] The composite binder adopts a phenolic resin-modified lignin compound system. The phenolic resin provides a high-strength cross-linking structure, while the modified lignin improves plasticity and environmental friendliness. The synergistic effect of the two increases the room temperature compressive strength of the taphole clay and enhances its bonding strength with the taphole clay residue, effectively preventing cracking and detachment.

[0027] This invention is applied to improve both the oxidation resistance and bonding properties of blast furnace taphole clay, thereby further extending the service life of the taphole clay.

[0028] This invention innovatively solves the problem of easy agglomeration of nano-silicon carbide by modifying it with a silane coupling agent and using a temperature-controlled stirring process at 80-100℃, thereby improving its dispersion uniformity in the clay matrix and enhancing its antioxidant performance. It innovatively adopts a composite aggregate of corundum-calcium aluminate-fused magnesia, combined with a dedicated drying pretreatment for calcium aluminate, and a precise dry-mixing process to improve the interfacial bonding strength of the aggregate, laying the foundation for high structural stability. A phenolic resin-modified lignin compound system replaces the traditional binder, and uniform compounding is achieved through temperature-controlled stirring in a water bath at 60-80℃, balancing bonding strength and environmental friendliness while reducing harmful volatilization. Attached Figure Description

[0029] Figure 1 is a photograph of the highly antioxidant and highly bound clay prepared in Example 1. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments.

[0031] Example 1

[0032] A method for preparing a highly antioxidant and highly binding shotcrete is as follows:

[0033] Step 1: Raw material pretreatment: Place nano-silicon carbide in a high-speed mixer. The nano-silicon carbide particle size is 50-100nm. Add silane coupling agent at a mass ratio of 0.1% of the nano-silicon carbide. Stir at 80℃ for 30min to perform surface modification. After cooling, mix with borax at a mass ratio of 7:3 to obtain an antioxidant composite additive for later use. Dry calcium titanate particles at 110℃ for 2h to remove moisture for later use.

[0034] Step 2, Preparation of premix: Add corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia to a mixer; the mass ratio of corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia is 4:3:3, wherein the particle size of corundum particles is 1-3 mm, the particle size of calcium aluminate titanate particles is 0.5-1 mm, and the particle size of fused magnesia is 0.1-0.5 mm; dry mix for 35 min to obtain mixed aggregate;

[0035] The following ingredients were added by mass: silicon carbide fine powder, silicon nitride iron fine powder, carbon black, antioxidant composite additive, and dispersant, in the following proportions: 8 parts silicon carbide, 6 parts silicon nitride iron fine powder, 4 parts carbon black, 1.5 parts antioxidant composite additive, and 0.5 parts polyacrylic acid. The mixture was then added to a planetary mixer and dry-mixed for 45 minutes to achieve uniform dispersion and obtain a mixed matrix.

[0036] Step 3: Preparation of the composite binder: Phenolic resin and nickel-modified lignin are placed in a water bath at a mass ratio of 5:3 and stirred at 70°C for 20 minutes until uniformly mixed to obtain the composite binder; Preparation of the gunning clay: According to the mass percentage, 45 parts of mixed aggregate are added to 55 parts of mixed matrix and stirred for 10 minutes. Then, 16 parts of the composite binder are slowly added and stirred for another 30 minutes to obtain a uniform gunning clay blank; The blank is extruded into clay to obtain gunning clay with high oxidation resistance and high binding strength.

[0037] The clay prepared in this embodiment has a Massia value of 0.65 MPa and a bulk density of 2.85 g / cm³. 3 Its room temperature compressive strength after calcination at 1450℃ reaches 18.5MPa.

[0038] Example 2

[0039] A method for preparing a highly antioxidant and highly binding shotcrete is as follows:

[0040] Step 1: Raw material pretreatment: Place nano-silicon carbide (50-100nm particle size) in a high-speed mixer, add silane coupling agent (0.5% of the mass of nano-silicon carbide), stir at 100℃ for 50min for surface modification, cool, and then mix with calcium borate at a mass ratio of 7:3 to obtain an antioxidant composite additive for later use; dry calcium titanate particles at 110℃ for 2h to remove moisture for later use.

[0041] Step 2, Preparation of premix: Add corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia to a mixer; the mass ratio of corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia is 4:3:3, wherein the particle size of corundum particles is 1-3 mm, the particle size of calcium aluminate titanate particles is 0.5-1 mm, and the particle size of fused magnesia is 0.1-0.5 mm; dry mix for 15 min to obtain mixed aggregate;

[0042] The following ingredients were added by mass: silicon carbide fine powder, silicon nitride iron fine powder, carbon black, antioxidant composite additive, and dispersant, in the following proportions: 20 parts silicon carbide, 2 parts silicon nitride iron fine powder, 1 part carbon black, 5 parts antioxidant composite additive, and 0.1 parts polyaspartic acid. The mixture was then added to a planetary mixer and dry-mixed for 45 minutes to achieve uniform dispersion and obtain a mixed matrix.

[0043] Step 3: Preparation of the composite binder: Phenolic resin and iron-modified lignin are placed in a water bath at a mass ratio of 5:3 and stirred at 60°C for 40 minutes until uniformly mixed to obtain the composite binder; Preparation of the gunning clay: 65 parts by mass of mixed aggregate are added to 35 parts by mass of mixed matrix and stirred for 30 minutes. Then, 8 parts by mass of composite binder are slowly added and stirred for another 50 minutes to obtain a uniform gunning clay blank; The blank is extruded into clay to obtain gunning clay with high oxidation resistance and high binding strength.

[0044] The clay prepared in this embodiment has a Massia value of 0.68 MPa and a bulk density of 2.87 g / cm³. 3 Its room temperature compressive strength after calcination at 1450℃ reaches 19.2MPa.

[0045] Example 3

[0046] A method for preparing a highly antioxidant and highly binding shotcrete is as follows:

[0047] Step 1: Raw material pretreatment: Place nano-silicon carbide in a high-speed mixer. The nano-silicon carbide particle size is 50-100nm. Add a silane coupling agent at a mass ratio of 0.3% of the nano-silicon carbide. Stir at 90℃ for 45min to perform surface modification. After cooling, mix it evenly with magnesium borate at a mass ratio of 7:3 to obtain an antioxidant composite additive for later use. Dry the calcium aluminate granules at 110℃ for 2h to remove moisture for later use.

[0048] Step 2, Preparation of premix: Add corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia to a mixer; the mass ratio of corundum particles, pretreated calcium aluminate titanate particles, and fused magnesia is 4:3:3, wherein the corundum particles have a particle size of 1-3 mm, the calcium aluminate particles have a particle size of 0.5-1 mm, and the fused magnesia particles have a particle size of 0.1-0.5 mm; dry mix for 25 min to obtain mixed aggregate;

[0049] The following ingredients were added by mass: silicon carbide fine powder, silicon nitride iron fine powder, carbon black, antioxidant composite additive, and dispersant, in the following proportions: silicon carbide 16 parts, silicon nitride iron fine powder 5 parts, carbon black 3 parts, antioxidant composite additive 3 parts, and polyacrylic acid 0.2 parts. The mixture was then added to a planetary mixer and dry-mixed for 30 minutes to achieve uniform dispersion and obtain a mixed matrix.

[0050] Step 3: Preparation of the composite binder: Phenolic resin and lanthanum-modified lignin are placed in a water bath at a mass ratio of 5:3 and stirred at 80°C for 35 minutes until homogeneous to obtain the composite binder; Preparation of the gunning clay: According to the mass percentage, 55 parts of mixed aggregate are added to 45 parts of mixed matrix and stirred for 25 minutes. Then, 10 parts of the composite binder are slowly added and stirred for another 45 minutes to obtain a uniform gunning clay blank; The blank is extruded into clay to obtain gunning clay with high oxidation resistance and high binding strength.

[0051] The clay prepared in this embodiment has a Massia value of 0.66 MPa and a bulk density of 2.90 g / cm³. 3 Its room temperature compressive strength after calcination at 1450℃ reaches 18.7MPa.

[0052] The above preparation method has the following advantages: the raw materials are non-toxic, harmless and easy to obtain, so the production cost is relatively low; the preparation process only requires stirring and molding, so the process is simple.

[0053] Figure 1 is a photograph of the highly antioxidant and highly bound potting mud prepared in Example 1.

[0054] The parts of this invention not described in detail are prior art. The above embodiments will help those skilled in the art to further understand this invention, but do not limit this invention in any way. Various changes in form, detail, or equivalents made using this invention without departing from the scope of the appended claims are all within the protection scope of this invention.

Claims

1. A method for preparing a high-antioxidant, high-binding-strength potting mix, characterized in that: Step 1: Raw Material Pretreatment: Place nano-silicon carbide in a high-speed mixer, add silane coupling agent (0.1-0.5% of the mass of nano-silicon carbide), stir at 80-100℃ for 30-50 min for surface modification, cool, and mix evenly with borate at a mass ratio of 7:3 to obtain an antioxidant composite additive for later use; dry calcium aluminate particles at 110℃ for 2 h to remove moisture for later use. Step 2: Preparation of Premix: Add corundum particles, pretreated calcium aluminate particles, and fused magnesia to a mixer; the corundum particle size is 1-3 mm, the calcium aluminate particle size is 0.5-1 mm, and the fused magnesia particle size is 0.1-0.5 mm; dry mix for 15-35 min to obtain a mixed aggregate. Materials: Add silicon carbide fine powder, silicon nitride iron fine powder, carbon black, antioxidant composite additive, and dispersant in the following proportions by mass: silicon carbide 8-20 parts, silicon nitride iron fine powder 2-6 parts, carbon black 1-4 parts, antioxidant composite additive 1.5-5 parts, and dispersant 0.1-0.5 parts. Add to a planetary mixer and dry mix for 25-45 minutes to uniformly disperse and obtain a mixed matrix. Step 3: Preparation of gunning clay: Add 45-65 parts of the mixed aggregate to 35-55 parts of the mixed matrix by mass, stir for 10-30 minutes, then slowly add 8-16 parts of the composite binder and continue stirring for 30-50 minutes to obtain a uniform gunning clay blank. Extrude the blank into clay to obtain high-oxidation-resistant and high-binding gunning clay.

2. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: The particle size of nano-silicon carbide is 50-100nm.

3. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: The mixture of corundum particles, pretreated calcium titanate particles, and fused magnesia is in a mass ratio of 4:3:

3.

4. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: In step one, the borate is one or more of borax, magnesium borate, and calcium borate.

5. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: In step two, the dispersant is one or more of polyacrylic acid, polymaleic acid, and polyaspartic acid.

6. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: The composite binder is a mixture of phenolic resin and modified lignin in a mass ratio of 5:

3. The phenolic resin is of the low free phenol type, and the modified lignin is one or two of nickel-modified lignin, iron-modified lignin, and lanthanum-modified lignin.

7. The method for preparing a high-antioxidant, high-binding clay according to claim 6, characterized in that: The composite binder is prepared by placing phenolic resin and modified lignin in a water bath and stirring at 60-80℃ for 20-40 minutes until they are mixed evenly to obtain the composite binder.

8. The method for preparing a high-antioxidant, high-binding clay according to claim 1, characterized in that: The highly antioxidant and highly bound gunning mud obtained in step three reacts with calcium aluminate and SiO2 to form a liquid phase that coats the particle surface, blocks the pores and encapsulates the SiC particles, while TiO2 is transformed into TiCN and distributed at the slag-gunning mud interface under high temperature conditions.

Images