A high temperature resistant and vibration resistant coating and its preparation method and application

Abstract

The present invention belongs to the technical field of refractory materials, and discloses a high temperature resistant and vibration resistant coating, and a preparation method and application thereof. The high temperature resistant and vibration resistant coating is composed of component A, component B and component C in a mass ratio of (0.8-1):(1-1.5):1, wherein component A includes sodium silicate aqueous solution and trimethoxysilane; component B includes corundum powder, nano-alumina and calcium hexaaluminate; component C includes zirconium oxide, magnesium oxide and a dispersion stabilizer. The present invention, through the design of raw material components and the control of the consolidation process during application, enables the coating to have good anti-reduction and anti-thermal shock properties while being resistant to high temperatures. It can be used as a protective coating for blast furnace hearth temperature measuring thermocouples, and can also be used as a blast furnace upper lining coating and other equipment coatings under high temperature and impact conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials, and in particular relates to a high temperature resistant and vibration resistant coating and a preparation method and application thereof. Background Art

[0002] Blast furnace tuyere coke sampling is to use mechanical or hydraulic power to insert the sampling tube from the tuyere of the blast furnace into the center of the blast furnace to take out coke, slag and other materials. It is one of the important methods to study the tuyere whirlpool area and the dead material column of the blast furnace. Installing a thermocouple in the sampling tube can measure the blast furnace hearth temperature while taking samples such as coke. The hearth temperature has an important influence on the fluidity and chemical reaction of the slag and iron in the lower part of the blast furnace.

[0003] The sampling of coke at the tuyere of a blast furnace is usually done after the blast furnace is shut down. The thermocouples arranged in the sampling tube are usually armored S-class thermocouples, and the protection tube of the thermocouple wire is made of high-temperature alloy steel. When measuring temperature, the outer surface of the protection tube of the thermocouple wire contacts high-temperature coke, molten slag and other materials. After the blast furnace is shut down, the furnace temperature at the tuyere plane is above 1350℃. The metal protection tube of the thermocouple wire is easily softened or damaged at high temperature, and cannot effectively protect the thermocouple wire, affecting the temperature measurement function of the thermocouple.

[0004] In order to solve the above problems, it is necessary to add a refractory coating to the outer surface of the metal protection tube of the thermocouple to effectively protect the thermocouple. However, since the sampling process requires a vibrator to push the sampling tube, the refractory material needs to be able to withstand high temperatures above 1350°C and also needs to be vibration-resistant to ensure that the coating does not fall off during sampling and vibration. Some existing inorganic refractory materials such as magnesium oxide, plate-shaped corundum, and high clay have poor vibration resistance under high temperature conditions and are difficult to adapt to actual application scenarios.

[0005] Therefore, a high temperature resistant and vibration resistant coating is needed, which is coated on the outer surface of the thermocouple metal protection tube to form a high temperature resistant and vibration resistant coating to ensure effective protection of the blast furnace hearth temperature measuring thermocouple. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high temperature resistant and vibration resistant coating and its preparation method and application in view of the deficiencies in the prior art. By designing the raw material components and controlling the consolidation process during application, the coating is made to have good anti-reduction and anti-thermal shock properties while being resistant to high temperatures.

[0007] In order to solve the technical problem raised by the present invention, the present invention provides a high temperature resistant and vibration resistant coating, which is composed of component A, component B and component C in a mass ratio of (0.8-1):(1-1.5):1, wherein component A includes a sodium silicate aqueous solution and trimethoxysilane, component B includes corundum powder, nano-alumina and calcium hexaaluminate, and component C includes zirconium oxide, magnesium oxide and a dispersion stabilizer.

[0008] In the above scheme, the SiO2 content of the sodium silicate aqueous solution is 25-30%, the Na2O content is 8-15%, and the modulus is 2-4.5.

[0009] In the above scheme, the mass of the trimethoxysilane is 5-8% of the mass of the sodium silicate aqueous solution.

[0010] In the above scheme, the Al2O3 content of the corundum powder is ≥93%, and the particle size is ≤0.15mm.

[0011] In the above solution, the particle size of the nano-alumina is 50 to 200 nm.

[0012] In the above scheme, the particle size of the calcium hexaaluminate is ≤0.2 mm.

[0013] In the above scheme, the mass ratio of the corundum powder, nano-alumina and calcium hexaaluminate is 1:(1.5-2):1.

[0014] In the above solution, the particle size of the zirconium oxide and magnesium oxide is ≤0.3 mm.

[0015] In the above scheme, the dispersion stabilizer is an aluminate coupling agent or o-benzoylsulfonimide.

[0016] In the above scheme, the mass ratio of zirconium oxide, magnesium oxide and dispersion stabilizer is 0.5:(0.3-0.5):1.

[0017] In the above scheme, the Na2O content in the powders such as corundum powder, nano-alumina, calcium hexaaluminate, zirconium oxide, and magnesium oxide is less than 0.3%.

[0018] The present invention also provides a method for preparing a high temperature resistant and vibration resistant coating, comprising the following steps:

[0019] First, component A, component B, and component C are mixed evenly according to their respective raw materials, then component B is added to component A and mixed evenly, and finally mixed evenly with component C to obtain a high temperature resistant and vibration resistant coating.

[0020] The present invention also provides an application method of the high temperature resistant and vibration resistant coating, comprising the following steps:

[0021] 1) Apply a layer of high temperature resistant and vibration resistant paint on the outer surface of the metal protection tube of the thermocouple, heat and solidify, apply another layer, heat and solidify, and repeat this process until the coating formed by solidification reaches a predetermined thickness;

[0022] 2) The coating is heated again to form a high temperature resistant and vibration resistant coating.

[0023] In the above solution, the single coating thickness of the high temperature resistant and vibration resistant coating is 1 to 2 mm.

[0024] In the above solution, the total thickness of the high temperature resistant and vibration resistant coating is 3 to 5 mm.

[0025] In the above scheme, the heating temperature in step 1) is 100-150° C., and the single consolidation time is 16-24 hours.

[0026] In the above scheme, the heating temperature in step 2) is 100-150° C. and the heating time is 72-96 hours.

[0027] The main technical concepts of the present invention are as follows:

[0028] 1) After component A and component C are mixed and heated to form an inorganic high-temperature glue; at the same time, the nano-alumina in component B and the zirconium oxide and magnesium oxide in component C are used together to significantly enhance the seismic resistance of the coating under high temperature conditions; the particle size of the corundum powder in component B must be strictly controlled below 0.15mm, otherwise the seismic resistance will be significantly deteriorated; the addition of calcium hexaaluminate in component B makes the coating have better anti-reduction properties, because the thermocouple is used inside the blast furnace hearth, the blast furnace hearth temperature exceeds 1350℃, and the blast furnace gas contains CO2 reducing gas. Fe2O3 in corundum powder and other powders is prone to reduction reaction, affecting the seismic resistance of the coating.

[0029] 2) Strictly control the Na2O content in various powders because Na2O will affect the density of the coating. Na2O combines with Al2O3 to generate β-Al2O3 with a certain conductivity, which will affect the performance of the coating.

[0030] 3) During application, the temperature and time of heating and consolidation must be guaranteed to ensure that the moisture content of the coating is controlled below 0.05%. Otherwise, under high temperature conditions, H2O will react with Al2O3 to generate Al(OH)3, and Al(OH)3 will undergo a reduction reaction with CO2 in blast furnace gas under high temperature conditions, affecting the seismic performance of the coating.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The invention makes the coating have good anti-reduction and anti-thermal shock properties while being resistant to high temperatures through the design of raw material components and the control of the consolidation process during application. The coating can be used as a protective coating for a thermocouple for measuring temperature in a blast furnace hearth. The coating does not fall off under conditions of a temperature above 1350°C, a vibration impact energy of 200kg, and an impact frequency of 200 to 300 times / min, thereby effectively protecting the thermocouple for measuring temperature. The coating can also be used as a coating for the lining of the upper part of a blast furnace and as a coating for equipment under other high temperature and impact conditions. DETAILED DESCRIPTION

[0033] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0034] In the following examples, the Na2O content in the powders of corundum powder, nano-alumina, calcium hexaaluminate, zirconium oxide, magnesium oxide, etc. used is less than 0.3%.

[0035] Example 1

[0036] A high temperature resistant and vibration resistant coating, comprising the following raw materials:

[0037] 1) Component A: sodium silicate aqueous solution (SiO2 content 25%, Na2O content 10%, modulus 2.58), 5% trimethoxysilane by mass of the sodium silicate aqueous solution;

[0038] 2) Component B: corundum powder (Al2O3 content 95%, particle size ≤ 0.1mm), nano alumina (particle size 50nm), calcium hexaaluminate (particle size ≤ 0.15mm), mass ratio 1:1.8:1;

[0039] 3) Component C: zirconium oxide (particle size ≤ 0.2 mm), magnesium oxide (particle size ≤ 0.2 mm), aluminate coupling agent, mass ratio 0.5:0.4:1;

[0040] The mass ratio of component A, component B and component C is 0.9:1.2:1.

[0041] The preparation method of the high temperature resistant and vibration resistant coating comprises the following steps: firstly, evenly mixing component A, component B and component C according to their respective raw materials, then adding component B to component A and evenly mixing, and finally evenly mixing with component C to obtain the high temperature resistant and vibration resistant coating.

[0042] The high temperature resistant and vibration resistant coating is used to protect the blast furnace hearth temperature measuring thermocouple. The application method is:

[0043] 1) Apply a layer of high temperature resistant and vibration resistant paint on the outer surface of the metal protection tube of the thermocouple. The thickness of a single coating is 1mm. Curing at 120℃ for 16h, then apply another layer and curing at 120℃ for 16h. Repeat this process until the total thickness of the coating formed by curing is 3mm.

[0044] 2) The coating is kept at a constant temperature of 120°C for 72 hours to form a high temperature resistant and vibration resistant coating.

[0045] The temperature measuring thermocouple was used to measure the temperature of the blast furnace hearth. Under the conditions of temperature above 1350°C, vibration impact energy of 200kg and impact frequency of 200-300 times / min, no shedding of the high-temperature resistant and vibration-resistant coating on the outer surface of the metal protection tube of the temperature measuring thermocouple was found, indicating that the thermal shock resistance is good.

[0046] Example 2

[0047] A high temperature resistant and vibration resistant coating, comprising the following raw materials:

[0048] 1) Component A: sodium silicate aqueous solution (SiO2 content 30%, Na2O content 8%, modulus 3.88), 7% trimethoxysilane by mass of the sodium silicate aqueous solution;

[0049] 2) Component B: corundum powder (Al2O3 content 95%, particle size 0.1mm), nano alumina (particle size 100nm), calcium hexaaluminate (particle size 0.15mm), mass ratio 1:2:1;

[0050] 3) Component C: zirconium oxide (particle size 0.2 mm), magnesium oxide (particle size 0.2 mm), o-benzoylsulfonyl imide, mass ratio 0.5:0.5:1;

[0051] The mass ratio of component A, component B and component C is 1:1.5:1.

[0052] The preparation method of the high temperature resistant and vibration resistant coating comprises the following steps: firstly, evenly mixing component A, component B and component C according to their respective raw materials, then adding component B to component A and evenly mixing, and finally evenly mixing with component C to obtain the high temperature resistant and vibration resistant coating.

[0053] The high temperature resistant and vibration resistant coating is used to protect the blast furnace hearth temperature measuring thermocouple. The application method is:

[0054] 1) Apply a layer of high temperature resistant and vibration resistant paint on the outer surface of the metal protection tube of the thermocouple. The thickness of a single coating is 2 mm. Curing at a constant temperature of 150°C for 18 hours, then apply another layer and curing at a constant temperature of 150°C for 18 hours. Repeat this process until the total thickness of the coating formed by curing is 4 mm.

[0055] 2) The coating is kept at a constant temperature of 150°C for 84 hours to form a high temperature resistant and vibration resistant coating.

[0056] The temperature measuring thermocouple was used to measure the temperature of the blast furnace hearth. Under the conditions of temperature above 1350°C, vibration impact energy of 200kg and impact frequency of 200-300 times / min, no shedding of the high-temperature resistant and vibration-resistant coating on the outer surface of the metal protection tube of the temperature measuring thermocouple was found, indicating that the thermal shock resistance is good.

[0057] Example 3

[0058] A high temperature resistant and vibration resistant coating, comprising the following raw materials:

[0059] 1) Component A: sodium silicate aqueous solution (SiO2 content 28%, Na2O content 14%, modulus 2.07), 8% of the mass of the sodium silicate aqueous solution of trimethoxysilane;

[0060] 2) Component B: corundum powder (Al2O3 content 95%, particle size 0.05mm), nano alumina (particle size 200nm), calcium hexaaluminate (particle size 0.1mm), mass ratio 1:1.5:1;

[0061] 3) Component C: zirconium oxide (particle size 0.1 mm), magnesium oxide (particle size 0.1 mm), aluminate coupling agent, mass ratio 0.5:0.3:1;

[0062] The mass ratio of component A, component B and component C is 0.8:1:1.

[0063] The preparation method of the high temperature resistant and vibration resistant coating comprises the following steps: firstly, evenly mixing component A, component B and component C according to their respective raw materials, then adding component B to component A and evenly mixing, and finally evenly mixing with component C to obtain the high temperature resistant and vibration resistant coating.

[0064] The high temperature resistant and vibration resistant coating is used to protect the blast furnace hearth temperature measuring thermocouple. The application method is:

[0065] 1) Apply a layer of high temperature resistant and vibration resistant paint on the outer surface of the metal protection tube of the temperature measuring thermocouple. The thickness of a single coating is 1.5mm. Curing at a constant temperature of 100℃ for 24h, then apply another layer and curing at a constant temperature of 100℃ for 24h. Repeat this process until the total thickness of the coating formed by curing is 4.5mm.

[0066] 2) The coating is kept at a constant temperature of 100°C for 96 hours to form a high temperature resistant and vibration resistant coating.

[0067] The temperature measuring thermocouple was used to measure the temperature of the blast furnace hearth. Under the conditions of temperature above 1350°C, vibration impact energy of 200kg and impact frequency of 200-300 times / min, no shedding of the high-temperature resistant and vibration-resistant coating on the outer surface of the metal protection tube of the temperature measuring thermocouple was found, indicating that the thermal shock resistance is good.

[0068] The above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above descriptions. It is not necessary and impossible to list all the implementation methods here, and the obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A high temperature resistant and vibration resistant coating, characterized in that: The invention comprises component A, component B and component C in a mass ratio of (0.8-1): (1-1.5): 1; the component A comprises a sodium silicate aqueous solution and trimethoxysilane, the mass of the trimethoxysilane being 5-8% of the mass of the sodium silicate aqueous solution; the component B comprises corundum powder, nano-alumina and calcium hexaaluminate in a mass ratio of 1: (1.5-2): 1, the particle size of the corundum powder being ≤ 0.15 mm; the component C comprises zirconium oxide, magnesium oxide and a dispersion stabilizer in a mass ratio of 0.5: (0.3-0.5): 1, the dispersion stabilizer being an aluminate coupling agent or o-benzoylsulfonimide; When used, apply a layer of the high temperature resistant and vibration resistant coating, heat and solidify, apply another layer, heat and solidify, and repeat this process until the solidified coating reaches a predetermined thickness, and heat the coating again to form a high temperature resistant and vibration resistant coating; wherein the heating and solidification temperature is 100~150°C, and the single solidification time is 16~24h; the heating treatment temperature is 100~150°C, and the time is 72~96h.

2. The high temperature resistant and vibration resistant coating according to claim 1, characterized in that: The sodium silicate aqueous solution has a SiO2 content of 25-30%, a Na2O content of 8-15%, and a modulus of 2-4.

5.

3. The high temperature resistant and vibration resistant coating according to claim 1, characterized in that: The Al2O3 content of the corundum powder is ≥93%; the particle size of the nano-alumina is 50-200nm; the particle size of the calcium hexaaluminate is ≤0.2mm; and the particle sizes of the zirconium oxide and magnesium oxide are ≤0.3mm.

4. The high temperature resistant and vibration resistant coating according to claim 1, characterized in that: The Na2O content in the corundum powder, nano-alumina, calcium hexaaluminate, zirconium oxide and magnesium oxide is less than 0.3%.

5. A method for preparing the high temperature resistant and vibration resistant coating according to any one of claims 1 to 4, characterized in that: The following steps are involved: First, component A, component B, and component C are mixed evenly according to their respective raw materials, then component B is added to component A and mixed evenly, and finally mixed evenly with component C to obtain a high temperature resistant and vibration resistant coating.

6. An application method of the high temperature resistant and vibration resistant coating according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Apply a layer of high temperature resistant and vibration resistant paint on the outer surface of the metal protection tube of the temperature measuring thermocouple, heat and solidify, apply another layer, heat and solidify, and repeat this process until the coating formed by solidification reaches the predetermined thickness; the heating and solidification temperature is 100~150℃, and the single solidification time is 16~24h; 2) The coating is heated again at a temperature of 100-150°C for a time of 72-96 hours to form a high temperature resistant and vibration resistant coating.

7. The application method of the high temperature resistant and vibration resistant coating according to claim 6, characterized in that: The single coating thickness of the high temperature resistant and vibration resistant coating is 1-2 mm, and the total coating thickness formed is 3-5 mm.