Lightweight repair material for the working layer of the lining of a steel rolling furnace

Abstract

The application relates to a light repairing material for a working layer of a rolling steel heating furnace lining, and belongs to the technical field of refractory materials. The light repairing material for the working layer of the rolling steel heating furnace lining comprises the following raw materials in parts by mass: 3-5 parts of fine powder material prepared by mixing magnesite and silica powder, 7-10 parts of light aggregate prepared by mixing magnesite and silica powder, 5-10 parts of light composite ceramic and 3-5 parts of a binder. The preparation method of the light composite ceramic is as follows: SiAlON powder, zirconium dioxide powder and CoCrFeNiTi powder are mixed to obtain mixed powder, a solvent is added into the mixed powder, ball milling is uniformly carried out, then expanded vermiculite and a foaming agent are added and uniformly mixed to obtain slurry, the slurry is spray dried and granulated, green bodies are obtained after compression molding, and the green bodies are vacuum sintered to obtain the light composite ceramic. The light repairing material for the working layer of the rolling steel heating furnace lining has a low heat preservation coefficient, heat emission in the rolling steel heating furnace is avoided, energy saving is achieved, and cost is saved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractory materials, and particularly relates to a light repair material for a working layer of a rolling steel heating furnace lining. BACKGROUND

[0002] The rolling steel heating furnace needs continuous high-temperature heating, and the refractory material of the rolling steel heating furnace lining is generally casted by castable. Under the effects of high-temperature long-time erosion, rapid cooling and heating cycle and chemical erosion, the refractory material of the rolling steel heating furnace lining will crack to generate cracks or the castable will fall off, which leads to damage of the rolling steel heating furnace lining and affects the use of the rolling steel heating furnace. The existing technology uses a repair material to repair the lining, and the repair material is generally a refractory material which can withstand high temperature, wear and chemical corrosion. However, the existing repair material is generally a heavy repair material which has high compactness, high bulk density and high thermal conductivity, and the furnace temperature of the rolling steel heating furnace will be dissipated. The fuel cost of a medium-sized heating furnace is about 100 million yuan per year, and the furnace heat dissipation will increase the fuel cost. Therefore, a repair material which can keep warm and save energy is needed to avoid the heat dissipation of the rolling steel heating furnace lining to the external environment. SUMMARY

[0003] The application aims to provide a light repair material for a working layer of a rolling steel heating furnace lining to solve the technical problem of the existing repair material which cannot keep warm and save energy.

[0004] In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

[0005] A light repair material for a working layer of a rolling steel heating furnace lining comprises the following raw materials in parts by mass: 3-5 parts of fine powder material prepared by mixing magnesite and silica powder, 7-10 parts of light aggregate prepared by mixing magnesite and silica powder, 5-10 parts of light composite ceramic and 3-5 parts of binder.

[0006] The preparation method of the light composite ceramic is as follows: SiAlON powder, zirconium dioxide powder and CoCrFeNiTi powder are mixed to obtain mixed powder, a solvent is added to the mixed powder, and the mixture is ball milled and uniformly mixed. Subsequently, expanded vermiculite and a foaming agent are added and uniformly mixed to obtain slurry. The slurry is spray dried and granulated, and then green bodies are obtained by compression molding. The green bodies are vacuum sintered to obtain the light composite ceramic.

[0007] Further, the mass fraction of Co in the CoCrFeNiTi powder is 20-25 %, the mass fraction of Cr is 20-22 %, the mass fraction of Fe is 20-22 %, the mass fraction of Ni is 20-25 %, and the mass fraction of Ti is 10-12 %.

[0008] Further, the mass ratio of the SiAlON powder, the zirconium dioxide powder and the CoCrFeNiTi powder is 1:1-2:0.1-0.2, the foaming agent accounts for 3-5 % of the mass of the mixed powder, the expanded vermiculite accounts for 2-5 % of the mass of the mixed powder; the foaming agent is ammonium bicarbonate.

[0009] Further, the temperature of the vacuum sintering is 1350-1520 DEG C, and the time of the vacuum sintering is 1-5h.

[0010] Further, the lightweight aggregate prepared by mixing magnesite and silica powder includes, in percentage by mass, 15-35 % of lightweight aggregate with a particle size of 0-1 mm, 30-50 % of lightweight aggregate with a particle size of 1-3 mm, and 15-35 % of lightweight aggregate with a particle size of 3-5 mm; and the preparation method of the lightweight aggregate is as follows: mixing magnesite and silica powder in a mass ratio of 2-3:1 to prepare green powder, and crushing the green powder after high-temperature sintering.

[0011] Further, the temperature of the high-temperature sintering is 1300-1350 DEG C.

[0012] Further, the fine powder material prepared by mixing magnesite and silica powder includes, in percentage by mass, 10-15 % of green powder and 85-90 % of lightweight aggregate prepared by mixing magnesite and silica powder.

[0013] Further, the particle size of the silica powder is ≤0.045 mm, the particle size of the magnesite is ≤0.088 mm, and the particle size of the lightweight composite ceramic is 20-500 nm.

[0014] Further, the binder is a mixture of silica sol and aluminum dihydrogen phosphate.

[0015] The beneficial effects of the present application are as follows:

[0016] The main component of the magnesite in the present application is magnesium carbonate, which is decomposed into carbon dioxide and magnesium oxide at high temperature, and the carbon dioxide escapes to reduce the mass of the lightweight repair material for the working layer of the rolling steel heating furnace, and at the same time, forms dense nanometer pores to increase the airtightness and heat preservation of the lightweight repair material for the working layer of the rolling steel heating furnace, and reduces heat loss.

[0017] When the lightweight composite ceramic is prepared, ammonium bicarbonate is decomposed at low temperature to produce carbon dioxide to escape, which reduces the mass and at the same time forms open pores and closed pores in the slurry; when the slurry is vacuum sintered, the expanded vermiculite expands under heat to increase the volume and reduce the mass, and at the same time, the expanded vermiculite expands under heat to extrude the slurry, forcing the slurry near the pores to adhere, reducing the open porosity in the slurry and increasing the heat preservation.

[0018] The light repair material for the working layer of the furnace lining of the steel rolling heating furnace has a low heat preservation coefficient, avoids heat emission in the steel rolling heating furnace, is more energy-saving, and saves cost. DETAILED DESCRIPTION

[0019] The application will be further described below in combination with the embodiments of the application.

[0020] CoCrFeNiTi 0.2 The mass fraction of Co is 25.07 %, the mass fraction of Cr is 22.12 %, the mass fraction of Fe is 23.76 %, the mass fraction of Ni is 24.97 %, and the mass fraction of Ti is 4.07 %.

[0021] CoCrFeNiTi 0.4 The mass fraction of Co is 23.63 %, the mass fraction of Cr is 20.85 %, the mass fraction of Fe is 22.39 %, the mass fraction of Ni is 23.53 %, and the mass fraction of Ti is 9.60 %.

[0022] CoCrFeNiTi 0.6 The mass fraction of Co is 23.18 %, the mass fraction of Cr is 20.46 %, the mass fraction of Fe is 21.97 %, the mass fraction of Ni is 23.09 %, and the mass fraction of Ti is 11.30 %.

[0023] CoCrFeNiTi 0.8 The mass fraction of Co is 22.34 %, the mass fraction of Cr is 19.72 %, the mass fraction of Fe is 21.17 %, the mass fraction of Ni is 22.25 %, and the mass fraction of Ti is 14.52 %.

[0024] CoCrFeNiMo 0.2 The mass fraction of Co is 24.03 %, the mass fraction of Cr is 21.13 %, the mass fraction of Fe is 22.93 %, the mass fraction of Ni is 23.99 %, and the mass fraction of Mo is 7.92 %.

[0025] CoCrFeNiAl 0.2 The mass fraction of Co is 25.53 %, the mass fraction of Cr is 22.52 %, the mass fraction of Fe is 24.19 %, the mass fraction of Ni is 25.42 %, and the mass fraction of Al is 2.34 %.

[0026] The preparation method of the SiAlON powder is as follows: 89.4% Si3N4 powder, 5.58% Al2O3 powder, 2.24% AlN powder and 2.78% Sm2O3 powder are mixed according to the mass percentage, and then are ground in a Si3N4 ball and a polyamide tank in a water-free molecular water, followed by drying, and then are ground through a 100-mesh screen.

[0027] Example 1

[0028] The lightweight repair material for the working layer of the furnace lining of the steel rolling heating furnace in Example 1 comprises the following raw materials: 3 kg of fine powder material prepared by mixing magnesite and silica powder, 7 kg of lightweight composite ceramic, 7 kg of lightweight aggregate prepared by mixing magnesite and silica powder, and 3 kg of binder, wherein the binder comprises 1 kg of silica sol and 2 kg of aluminum dihydrogen phosphate. The particle size of the silica powder is ≤0.045 mm, and the particle size of the magnesite is ≤0.088 mm. The particle size of the lightweight composite ceramic is 20-500 nm.

[0029] The lightweight aggregate prepared by mixing magnesite and silica powder comprises, according to the mass percentage, 35% of lightweight aggregate with a particle size of 0-1 mm, 30% of lightweight aggregate with a particle size of 1-3 mm, and 35% of lightweight aggregate with a particle size of 3-5 mm.

[0030] The preparation method of the lightweight aggregate is as follows: 12 kg of magnesite and 4 kg of silica powder are uniformly mixed to obtain raw powder, and the raw powder is sintered at 1350°C for 3 h, and then is broken to obtain lightweight aggregate with different particle sizes.

[0031] The fine powder material prepared by mixing magnesite and silica powder comprises 0.3 kg of the above-mentioned raw powder and 2.7 kg of lightweight aggregate prepared by mixing magnesite and silica powder.

[0032] The preparation method of the lightweight composite ceramic is as follows: 10 kg of SiAlON powder, 10 kg of zirconium dioxide powder and 1 kg of CoCrFeNiTi powder are mixed to obtain mixed powder, anhydrous ethanol is added to the mixed powder, and ball milling is performed at a ball-to-material ratio of 10:1 and a rotation speed of 200 r / min for 24 h, then 0.7 kg of expanded vermiculite and 0.5 kg of ammonium bicarbonate are uniformly mixed to obtain slurry, the slurry is spray-dried and granulated, and a green body is obtained by compression molding at 150 MPa, and then the green body is sintered in a vacuum at 1350°C for 2 h to obtain the lightweight composite ceramic. In the CoCrFeNiTi powder, the mass fraction of Co is 23.18%, the mass fraction of Cr is 20.46%, the mass fraction of Fe is 21.97%, the mass fraction of Ni is 23.09%, and the mass fraction of Ti is 11.30%.

[0033] Example 2

[0034] The light repair material for the working layer of the furnace lining of the steel rolling heating furnace of embodiment 2 comprises the following raw materials: 5 kg of fine powder material prepared by mixing magnesite and silica powder, 5 kg of light composite ceramic, 10 kg of light aggregate prepared by mixing magnesite and silica powder, and 5 kg of binder, wherein the binder comprises 2.5 kg of silica sol and 2.5 kg of aluminum dihydrogen phosphate. The particle size of the silica powder is ≤0.045 mm, and the particle size of the magnesite is ≤0.088 mm. The particle size of the light composite ceramic is 20-500 nm.

[0035] The light aggregate prepared by mixing magnesite and silica powder comprises, by mass percentage, 15 % of light aggregate with a particle size of 0-1 mm, 50 % of light aggregate with a particle size of 1-3 mm, and 35 % of light aggregate with a particle size of 3-5 mm.

[0036] The preparation method of the light aggregate is as follows: 8 kg of magnesite and 4 kg of silica powder are uniformly mixed to obtain raw powder, and the raw powder is sintered at 1300 ℃ for 3 h and then broken to obtain light aggregate with different particle sizes.

[0037] The fine powder material prepared by mixing magnesite and silica powder comprises 0.75 kg of the above-mentioned raw powder and 4.25 kg of light aggregate prepared by mixing magnesite and silica powder.

[0038] The preparation method of the light composite ceramic is as follows: 10 kg of SiAlON powder, 20 kg of zirconium dioxide powder, and 2 kg of CoCrFeNiTi powder are mixed to obtain a mixed powder, anhydrous ethanol is added to the mixed powder, ball milling is performed for 24 h at a ball-to-powder ratio of 10:1 and a rotation speed of 200 r / min, then 1.6 kg of expanded vermiculite and 1.6 kg of ammonium bicarbonate are uniformly mixed to obtain a slurry, the slurry is spray-dried and granulated, and a green body is obtained by compression molding at 150 MPa, and the green body is sintered in vacuum at 1520 ℃ for 1 h. In the CoCrFeNiTi powder, the mass fraction of Co is 23.18 %, the mass fraction of Cr is 20.46 %, the mass fraction of Fe is 21.97 %, the mass fraction of Ni is 23.09 %, and the mass fraction of Ti is 11.30 %.

[0039] Embodiment 3

[0040] The lightweight repair material for the working layer of the furnace lining of the steel rolling heating furnace of Example 3 comprises the following raw materials: 4 kg of fine powder material prepared by mixing magnesite and silica powder, 10 kg of lightweight composite ceramic, 8 kg of lightweight aggregate prepared by mixing magnesite and silica powder, and 4 kg of binder, wherein the binder comprises 1 kg of silica sol and 3 kg of aluminum dihydrogen phosphate. The particle size of the silica powder is ≤0.045 mm, and the particle size of the magnesite is ≤0.088 mm. The mass fraction of Co in the CoCrFeNiTi powder is 23.18 %, the mass fraction of Cr is 20.46 %, the mass fraction of Fe is 21.97 %, the mass fraction of Ni is 23.09 %, and the mass fraction of Ti is 11.30 %.

[0041] The lightweight aggregate prepared by mixing magnesite and silica powder comprises, by mass percentage, 20 % of lightweight aggregate with a particle size of 0-1 mm, 45 % of lightweight aggregate with a particle size of 1-3 mm, and 35 % of lightweight aggregate with a particle size of 3-5 mm.

[0042] The preparation method of the lightweight aggregate is as follows: 8 kg of magnesite and 4 kg of silica powder are uniformly mixed to obtain raw powder, and the raw powder is sintered at 1350 ℃ for 3 h and then broken to obtain lightweight aggregate with different particle sizes.

[0043] The fine powder material prepared by mixing magnesite and silica powder comprises 0.4 kg of the above-mentioned raw powder and 3.6 kg of lightweight aggregate prepared by mixing magnesite and silica powder.

[0044] The preparation method of the lightweight composite ceramic is as follows: 10 kg of SiAlON powder, 10 kg of zirconium dioxide powder, and 2 kg of CoCrFeNiTi powder are mixed to obtain a mixed powder, anhydrous ethanol is added to the mixed powder, ball milling is performed for 24 h at a ball-to-powder ratio of 10:1 and a rotation speed of 200 r / min, then 0.88 kg of expanded vermiculite and 0.88 kg of ammonium bicarbonate are uniformly mixed to obtain a slurry, the slurry is spray-dried and granulated, and a green body is obtained by compression molding at 150 MPa, and the green body is sintered in vacuum at 1400 ℃ for 5 h.

[0045] Comparative Example 1

[0046] The lightweight repair material for the working layer of the furnace lining of the steel rolling heating furnace of Comparative Example 1 is substantially the same as that of Example 1, and the difference between the lightweight repair material for the working layer of the furnace lining of the steel rolling heating furnace of Comparative Example 1 and that of Example 1 is that no zirconium dioxide powder is added in Comparative Example 1, and the mass is made up according to the proportion of SiAlON powder and CoCrFeNiTi powder in Example 1.

[0047] Comparative Example 2

[0048] The working layer of the rolling heating furnace lining of Comparative Example 2 was made of the same lightweight repair material as that of Example 1, except that no SiAlON powder was added in Comparative Example 2, and the mass was made up according to the ratio of the zirconium dioxide powder to the CoCrFeNiTi powder of Example 1.

[0049] Comparative Example 3

[0050] The working layer of the rolling heating furnace lining of Comparative Example 3 was made of the same lightweight repair material as that of Example 1, except that no CoCrFeNiTi powder was added in Comparative Example 3, and the mass was made up according to the ratio of the zirconium dioxide powder to the SiAlON powder of Example 1.

[0051] The working layer of the rolling heating furnace lining of Comparative Examples 4-7 was made of the same lightweight repair material as that of Example 1, except that the differences between Comparative Examples 4-7 and Example 1 were as shown in Table 1.

[0052] Table 1: Amount of each substance added in Comparative Examples 4-7

[0053]

[0054] Comparative Example 8

[0055] The working layer of the rolling heating furnace lining of Comparative Example 8 was made of the same lightweight repair material as that of Example 1, except that no expanded vermiculite was added in Comparative Example 8.

[0056] Test Example 1

[0057] Effect of different raw materials on the thermal conductivity of the repair material

[0058] Table 2: Effect of different raw materials on the thermal conductivity of the repair material

[0059]

[0060] 10 kg of SiAlON powder, 10 kg of zirconium dioxide powder, and 1 kg of each of the raw materials listed in Table 2 were mixed separately to obtain a mixed powder. Anhydrous ethanol was added to the mixed powder, and the mixture was ball-milled for 24 h to obtain a slurry with a ball-to-powder ratio of 10:1 and a rotation speed of 200 r / min. The slurry was spray-dried and granulated, then pressed into green bodies at 150 MPa. After vacuum sintering at 1350 ℃ for 2 h, a composite ceramic was obtained. 3 kg of fine powder prepared by mixing magnesite and silica micro powder, 7 kg of composite ceramic, 7 kg of lightweight aggregate prepared by mixing magnesite and silica micro powder, and 3 kg of binder were mixed evenly to form a colloidal substance. This substance was then dried at 120 ℃ for 12 h, sintered at 550 ℃ for 2 h, sintered at 1350 ℃ for 1 h, and finally naturally cooled to obtain repair materials one through three. As shown in Table 2, repair material one has the lowest thermal conductivity.

[0061] Experimental Example 2

[0062] The Influence of Different CoCrFeNiTi Compositions on the Thermal Conductivity of Repair Material

[0063] Table 3. Effect of different CoCrFeNiTi compositions on the thermal conductivity of the repair material.

[0064]

[0065] 10 kg of SiAlON powder, 10 kg of zirconium dioxide powder, and 1 kg of the raw materials listed in Table 3 were mixed separately to obtain a mixed powder. Anhydrous ethanol was added to the mixed powder, and the mixture was ball-milled for 24 h to obtain a slurry with a ball-to-powder ratio of 10:1 and a rotation speed of 200 r / min. The slurry was spray-dried and granulated, then pressed into green bodies at 150 MPa. After vacuum sintering at 1350 ℃ for 2 h, a composite ceramic was obtained. 3 kg of fine powder prepared by mixing magnesite and silica micro powder, 7 kg of composite ceramic, 7 kg of lightweight aggregate prepared by mixing magnesite and silica micro powder, and 3 kg of binder were mixed evenly to form a colloidal substance. This substance was then dried at 120 ℃ for 12 h, sintered at 550 ℃ for 2 h, sintered at 1350 ℃ for 1 h, and finally naturally cooled to obtain repair materials four to seven. As shown in Table 3, repair material six has the lowest thermal conductivity.

[0066] Experimental Example 3

[0067] The repair materials of Examples 1-3 and Comparative Examples 1-8 were coated on the working layer of the furnace lining of the steel rolling heating furnace, dried at 120 °C for 12 h, sintered at 550 °C for 2 h, sintered at 1350 °C for 1 h, and finally cooled naturally with the furnace.

[0068] Compressive strength was tested according to GB / T5072-2008;

[0069] The bending strength was tested according to GB / T 3002-1982;

[0070] The linear change after burning (1350℃, 3h) was tested according to GB / T 3997.1-1998;

[0071] The thermal shock stability (1100℃, air cooling) was tested according to YB / T 3761-95;

[0072] The test results are shown in Table 4.

[0073] Table 4 Performance test results of the repair materials of Examples 1-3 and Comparative Examples 1-8

[0074]

[0075] As can be seen from Examples 1-3 and Comparative Examples 1-8, only when the SiAlON powder, zirconia powder and CoCrFeNiTi powder coexist, and the ratio of the SiAlON powder, zirconia powder and CoCrFeNiTi powder is between 1:1-2:0.1-0.2, the thermal conductivity of the prepared lightweight repair material for the working layer of the rolling steel heating furnace lining is the lowest.

Claims

1. A lightweight repair material for the working layer of a steel rolling heating furnace lining, characterized in that, The raw materials included by weight are: 3-5 parts of fine powder material prepared by mixing magnesite and silica powder, 7-10 parts of lightweight aggregate prepared by mixing magnesite and silica powder, 5-10 parts of lightweight composite ceramics, and 3-5 parts of binder. The preparation method of the lightweight composite ceramic is as follows: SiAlON powder, zirconium dioxide powder, and CoCrFeNiTi powder are mixed to obtain a mixed powder. A solvent is added to the mixed powder, and the mixture is ball-milled and mixed evenly. Then, expanded vermiculite and a foaming agent are added and mixed evenly to obtain a slurry. The slurry is spray-dried and granulated, pressed into shape to obtain a green body, and then vacuum sintered to obtain the final product. The mass ratio of SiAlON powder, zirconium dioxide powder, and CoCrFeNiTi powder is 1:1-2:0.1-0.

2.

2. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 1, characterized in that, The CoCrFeNiTi powder contains 20-25% Co, 20-22% Cr, 20-22% Fe, 20-25% Ni, and 10-12% Ti by mass.

3. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 1, characterized in that, The foaming agent accounts for 3-5% of the mass of the mixed powder, and the expanded vermiculite accounts for 2-5% of the mass of the mixed powder; the foaming agent is ammonium bicarbonate.

4. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 1, characterized in that, The vacuum sintering temperature is 1350-1520 ℃, and the vacuum sintering time is 1-5 h.

5. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 1, characterized in that, The lightweight aggregate prepared by mixing magnesite and silica micro powder comprises, by mass percentage: 15-35% lightweight aggregate with a particle size of 0-1 mm, 30-50% lightweight aggregate with a particle size of 1-3 mm, and 15-35% lightweight aggregate with a particle size of 3-5 mm. The preparation method of the lightweight aggregate is as follows: magnesite and silica micro powder are mixed at a mass ratio of 2-3:1 to form raw powder, which is then sintered at high temperature and crushed to obtain the final product.

6. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 5, characterized in that, The high-temperature sintering temperature is 1300-1350 ℃.

7. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 5, characterized in that, The fine powder material prepared by mixing magnesite and silica powder comprises, by mass percentage: 10-15% raw powder and 85-90% lightweight aggregate prepared by mixing magnesite and silica powder.

8. The lightweight repair material for the working layer of the furnace lining of a steel rolling heating furnace according to any one of claims 1-7, characterized in that, The silica micro powder has a particle size ≤0.045 mm, the magnesite has a particle size ≤0.088 mm, and the lightweight composite ceramic has a particle size of 20-500 nm.

9. The lightweight repair material for the working layer of the steel rolling heating furnace lining according to claim 1, characterized in that: The binder is a mixture of silica sol and aluminum dihydrogen phosphate.

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