A water-free environmentally friendly hot patching material and its preparation method and use method

Abstract

The present invention relates to the technical field of refractory materials, and provides a water-free environmentally friendly hot patching material, a preparation method thereof, and a method for using the same. The present invention uses fused magnesia as the main raw material, aluminum-silicon composite ultrafine powder as a binder, and simultaneously adds a self-flowing agent and a sintering agent. The obtained water-free environmentally friendly hot patching material has good hot self-flowing properties, good adhesion, short sintering time, and a long service life of the furnace body after repair. Compared with traditional hot patching materials, the water-free environmentally friendly hot patching material provided by the present invention does not contain harmful substances such as asphalt, tar, benzene, anthracene, etc., and there is no black smoke or harmful substance emissions during the furnace repair process, which is safe and environmentally friendly. Compared with water-based hot patching materials, the water-free environmentally friendly hot patching material provided by the present invention does not require on-site stirring, will not spray a large amount of water vapor when repairing the furnace, and has no safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory materials, and in particular to a water-free environmentally friendly hot patching material and a preparation method and a use method thereof. Background Art

[0002] At present, new technologies in the steel industry at home and abroad are developing rapidly, and the service life of steelmaking furnaces is an important technical and economic indicator. It is particularly important to increase the service life of furnaces and improve the safety factor of equipment.

[0003] Hot patch material (also known as hot patch material) is a refractory material commonly used in steel mills for rapid furnace repairs. Because the repairs are performed while the furnace is in operation, it's called hot patching. Traditional hot patch materials typically use fused magnesia or magnesium-calcium as the primary raw materials, modified asphalt as a binder, and flow aids and sintering agents. Once packaged as required, they are ready for use. Traditional hot patch materials produce large amounts of black smoke during the repair process, emitting large amounts of CO2, SO2, soot, and toxic and hazardous substances such as benzene and aldehydes, significantly impacting the environment. Furthermore, the sintering time is long, shortening the service life of the repaired furnace, which can last for only 20 cycles.

[0004] With increasing national environmental protection requirements, traditional hot patching materials using asphalt binders are gradually being phased out of the market, while environmentally friendly water-based hot patching materials are becoming the dominant product. These materials omit asphalt and instead utilize binders such as sodium tripolyphosphate and sodium hexametaphosphate. While these materials offer advantages such as smoke-free operation, fast sintering times, and a long service life, they are complex to use and require a considerable amount of on-site space for a mixer. After mixing with water and bagging, if the mixing time exceeds 30 minutes, water-material stratification will occur, seriously affecting the effectiveness of the patching process. If the mixing time exceeds 60 minutes, the material becomes unusable. The addition of 8% to 10% water during mixing can cause gas corrosion in high-temperature furnaces, especially when patching the bottom of the furnace, which often results in water splashing. This poses a significant risk to nearby workers and poses a safety risk. Summary of the Invention

[0005] In view of this, the present invention provides a water-free, environmentally friendly hot patching material and its preparation and use methods. The water-free, environmentally friendly hot patching material provided by the present invention is safe and environmentally friendly, does not require the addition of water, and will not cause problems such as water accumulation and splashing during use, thus posing no safety risks.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A water-free, environmentally friendly hot patch material, comprising the following components by mass: 75-80 parts of 96 fused magnesia, 8-10 parts of 97 fused magnesia, 5-7 parts of alumina micropowder, 4-6 parts of aluminum silicon composite ultrafine powder, 1-5 parts of sintering agent, and 0.2-1.1 parts of self-flowing agent;

[0008] The sintering agent is one or both of ferrosilicon nitride and metallic silicon; the self-flowing agent is one or both of magnesium stearate and polyacrylamide.

[0009] Preferably, the 96 fused magnesia is obtained by compounding a first 96 fused magnesia, a second 96 fused magnesia and a third 96 fused magnesia, the particle size of the first 96 fused magnesia is greater than 3 mm and less than or equal to 5 mm, the particle size of the second 96 fused magnesia is greater than 1 mm and less than or equal to 3 mm, the particle size of the third 96 fused magnesia is greater than 0 and less than or equal to 1 mm, and the mass ratio of the first 96 fused magnesia, the second 96 fused magnesia and the third 96 fused magnesia is 18-22:30-35:25-28.

[0010] Preferably, the mesh size of the 97 fused magnesia is 200 meshes.

[0011] Preferably, the particle size of the alumina powder is 1.5 to 5 μm.

[0012] Preferably, the particle size of the aluminum-silicon composite ultrafine powder is 0.5 to 1.5 μm.

[0013] Preferably, the mesh size of the ferrosilicon nitride is 200-325 meshes, and the mesh size of the metallic silicon is 200-325 meshes.

[0014] Preferably, the sintering agent includes ferrosilicon nitride and metallic silicon, and the mass ratio of the ferrosilicon nitride to metallic silicon is 2-3:2-1.

[0015] Preferably, the self-flowing agent comprises magnesium stearate and polyacrylamide, and the mass ratio of magnesium stearate to polyacrylamide is 3-4:2-1.

[0016] The present invention also provides a method for preparing the anhydrous environmentally friendly hot patching material described in the above scheme, comprising the following steps:

[0017] The water-free environmentally friendly hot patch material is obtained by mixing 96 fused magnesia, 97 fused magnesia, alumina fine powder, aluminum silicon composite ultrafine powder, a sintering agent and a self-flowing agent.

[0018] The present invention also provides a method for using the water-free environmentally friendly hot patching material described in the above scheme, comprising the following steps:

[0019] Without stopping the furnace, the water-free environmentally friendly hot patching material described in the above scheme is directly put into the steelmaking furnace to be repaired and sintered for 15 to 25 minutes.

[0020] The present invention provides an anhydrous, environmentally friendly hot patch material, comprising the following components by weight: 75-80 parts of 96% fused magnesia, 8-10 parts of 97% fused magnesia, 5-7 parts of alumina powder, 4-6 parts of aluminum-silicon composite ultrafine powder, 1-5 parts of a sintering agent, and 0.2-1.1 parts of a flow agent; the sintering agent is one or both of ferrosilicon nitride and metallic silicon; and the flow agent is one or both of magnesium stearate and polyacrylamide. The present invention utilizes fused magnesia as the primary raw material, aluminum-silicon composite ultrafine powder as a binder, and both a flow agent and a sintering agent. The resulting anhydrous, environmentally friendly hot patch material exhibits excellent hot flowability, good adhesion, a short sintering time, and a long service life for the repaired furnace body. Compared with traditional hot patching materials, the water-free environmentally friendly hot patching materials provided by the present invention do not contain harmful substances such as asphalt, tar, benzene, anthracene, etc., and there is no black smoke or harmful substance emissions during the furnace patching process, which is safe and environmentally friendly. Compared with water-based hot patching materials, the water-free environmentally friendly hot patching materials provided by the present invention do not require on-site stirring, do not spray a large amount of water vapor during the furnace patching, and have no safety hazards. In addition, the sintering time of a traditional hot patching material is 40 to 50 minutes. The water-based hot patching material will reduce the furnace temperature due to the emission of a large amount of water vapor, which is not conducive to the continuous production of the steel plant. The water-free environmentally friendly hot patching materials provided by the present invention only take 15 to 25 minutes to repair once, and will not reduce the furnace temperature, which is conducive to the continuous production of the steel plant. In addition, the service life of the furnace body repaired with the hot patching material of the present invention is long. Under the same conditions, the service life of the furnace body repaired with the hot patching material of the present invention is twice that of the traditional repairing material. DETAILED DESCRIPTION

[0021] The present invention provides an anhydrous environmentally friendly hot patch material, which is composed of the following components in parts by mass: 75-80 parts of 96 fused magnesia, 8-10 parts of 97 fused magnesia, 5-7 parts of alumina micropowder, 4-6 parts of aluminum silicon composite ultrafine powder, 1-5 parts of sintering agent, and 0.2-1.1 parts of self-flowing agent;

[0022] The sintering agent is one or both of ferrosilicon nitride and metallic silicon; the self-flowing agent is one or both of magnesium stearate and polyacrylamide.

[0023] Unless otherwise specified, all raw materials used in the present invention are commercially available products.

[0024] The anhydrous environmentally friendly hot patch material provided by the present invention comprises 75 to 80 parts of 96 fused magnesia in parts by mass; in the present invention, the mass fraction of magnesium oxide in the 96 fused magnesia is ≥96%, the mass fraction of calcium oxide is ≤2%, the mass fraction of silicon dioxide is ≤1%, the mass fraction of aluminum oxide is ≤0.5%, the loss on ignition is ≤0.3wt%, and the bulk density is ≥3.25g / cm 3In the present invention, the 96 fused magnesia is obtained by compounding a first 96 fused magnesia, a second 96 fused magnesia and a third 96 fused magnesia. The particle size of the first 96 fused magnesia is greater than 3 mm and less than or equal to 5 mm (denoted as 3-5 mm), the particle size of the second 96 fused magnesia is greater than 1 mm and less than or equal to 3 mm (denoted as 1-3 mm), and the particle size of the third 96 fused magnesia is greater than 0 and less than or equal to 1 mm (denoted as 0-1 mm). The mass ratio of the first 96 fused magnesia, the second 96 fused magnesia and the third 96 fused magnesia is preferably 18-22:30-35:25-28, and more preferably 20:35:25.

[0025] Based on the mass fraction of 96 fused magnesia, the water-free environmentally friendly hot patch material provided by the present invention includes 8 to 10 parts of 97 fused magnesia, preferably 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts. In the present invention, the mass fraction of magnesium oxide in the 97 fused magnesia is ≥97%, the mass fraction of calcium oxide is ≤1.5%, the mass fraction of silicon dioxide is ≤1%, the mass fraction of aluminum oxide is ≤0.5%, the loss on ignition is ≤0.3wt%, and the bulk density is ≥3.25g / cm 3 ; The mesh size of the 97 fused magnesia is preferably 200 meshes.

[0026] The anhydrous, environmentally friendly hot patch material provided by the present invention comprises 5 to 7 parts, preferably 5, 5.5, 6, 6.5, or 7 parts, of alumina powder, based on the mass fraction of 96% fused magnesia. In the present invention, the particle size of the alumina powder is preferably 1.5 to 5 μm, more preferably 3 to 5 μm, and the mass fraction of aluminum oxide in the alumina powder is ≥ 99%. In the present invention, the alumina powder can quickly react chemically with the magnesia under the action of a sintering agent to form spinel. As the amount of spinel increases, the material's slag resistance improves, its density increases, and its erosion and wear resistance improve.

[0027] Based on the mass fraction of 96 fused magnesia, the water-free environmentally friendly hot repair material provided by the present invention includes 4 to 6 parts of aluminum-silicon composite ultrafine powder, preferably 4 parts, 4.5 parts, 5 parts, 5.5 parts or 6 parts. In the present invention, the particle size of the aluminum-silicon composite ultrafine powder is preferably 0.5 to 1.5 μm, more preferably 0.5 to 1 μm; the mass fraction of aluminum oxide in the aluminum-silicon composite ultrafine powder is preferably 45 to 48%, and the mass fraction of silicon dioxide is preferably 52 to 55%; the aluminum-silicon composite ultrafine powder used in the present invention is a commercially available product of Qingdao Shouxin Metallurgical Auxiliary Materials Technology Co., Ltd. The present invention uses aluminum-silicon composite ultrafine powder as an auxiliary flow aid and binder, which can quickly improve the fluidity of the hot repair material under low temperature conditions. After self-leveling, as the temperature rises, a strong cubic Si-O bond is formed, and spinel is generated at the same time, which not only improves the strength of the material but also improves the slag resistance of the material.

[0028] Based on the mass fraction of 96 fused magnesia, the water-free environmentally friendly hot patch material provided by the present invention includes 1 to 5 parts of a sintering agent, preferably 2 to 4 parts. In the present invention, the sintering agent includes one or both of ferrosilicon nitride and metallic silicon; the mesh size of the ferrosilicon nitride is preferably 200 to 325 mesh, more preferably 200 to 250 mesh, and the mesh size of the metallic silicon is preferably 200 to 325 mesh, more preferably 250 to 325 mesh; when the sintering agent is ferrosilicon nitride, the mass fraction of the ferrosilicon nitride is preferably 2 to 3 parts, and when the sintering agent is metallic silicon, the mass fraction of the metallic silicon is preferably 1 to 2 parts; when the sintering agent includes both ferrosilicon nitride and metallic silicon, the mass ratio of the ferrosilicon nitride to metallic silicon is preferably 2 to 3:1 to 2. Ferrosilicon nitride contains ductile particles that can enhance the iron-metal compound ferrosilicide. Ferrosilicon promotes the sintering of the hot patch material and improves the bonding strength between oxides and non-oxides. As the amount of ferrosilicon nitride added to the hot patch material increases, the high-temperature flexural strength also increases significantly. However, beyond a certain amount, the porosity of the hot patch material also increases, and the high-temperature strength decreases accordingly. Metallic silicon is a gray-black powdered amorphous silicon. Its chemical properties are active, reacting violently with oxygen and reacting with metals such as magnesium, calcium, and iron to form silicides, which promote further sintering of the hot patch material and improve its sintering strength. The present invention strictly controls the particle size of each raw material in the water-free, environmentally friendly hot patch material, ensuring good fluidity and rapid leveling.

[0029] Based on the mass fraction of 96 fused magnesia sand, the water-free environmentally friendly hot patch material provided by the present invention includes 0.2 to 1.1 parts of self-flowing agent, preferably 0.5 to 1 parts. In the present invention, the self-flowing agent is one or both of magnesium stearate and polyacrylamide, and the magnesium stearate and polyacrylamide are preferably in powder form; when the self-flowing agent is magnesium stearate, the mass fraction of the magnesium stearate is preferably 0.2 to 0.6 parts, preferably 0.5 parts; when the self-flowing agent is polyacrylamide, the mass fraction of the polyacrylamide is preferably 0.3 to 0.5 parts; when the self-flowing agent includes both magnesium stearate and polyacrylamide, the mass ratio of magnesium stearate to polyacrylamide is preferably 4 to 5:2 to 3. The present invention adopts the above-mentioned self-flowing agent to improve the self-leveling performance of the hot patch material at high temperature.

[0030] The present invention also provides a method for preparing the anhydrous environmentally friendly hot patching material described in the above scheme, comprising the following steps:

[0031] The water-free environmentally friendly hot patch material is obtained by mixing 96 fused magnesia, 97 fused magnesia, alumina fine powder, aluminum silicon composite ultrafine powder, a sintering agent and a self-flowing agent.

[0032] The present invention has no special requirements on the specific method of mixing, as long as the above raw materials can be mixed evenly.

[0033] The present invention also provides a method for using the water-free environmentally friendly hot patching material described in the above scheme, comprising the following steps:

[0034] Without stopping the furnace, the water-free environmentally friendly hot patching material described in the above scheme is directly put into the steelmaking furnace to be repaired and sintered for 15 to 25 minutes.

[0035] In the present invention, the sintering is preferably performed at the temperature of the steelmaking furnace itself without adjusting the temperature of the steelmaking furnace. In a specific embodiment of the present invention, the temperature of the steelmaking furnace is 1250-1450°C.

[0036] The present invention has no special requirements on the specific type of the kiln. All commonly used steelmaking furnaces in steel mills can be repaired using the water-free environmentally friendly hot patching material of the present invention, such as converters, electric furnaces, heating furnaces, etc.

[0037] In the present invention, the amount of the water-free environmentally friendly hot patching material is preferably determined according to the damage of the repaired surface. In a specific embodiment of the present invention, the amount used each time is preferably 1 to 2 tons. The present invention does not require stopping the furnace during repair. The hot patching material can be directly poured into the furnace using a scrap steel trough, and can be put into use after sintering for 15 to 25 minutes using residual heat.

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] The indicators of the fused magnesia, alumina fine powder and aluminum silicon composite ultrafine powder used in the examples are shown in Table 1.

[0040] Table 1 Performance indicators of fused magnesia, alumina powder and aluminum silicon composite ultrafine powder (wt%)

[0041]

[0042] The 96 fused magnesia used in the embodiment is obtained by compounding 96 fused magnesia with particle sizes of 3-5 mm, 1-3 mm and 0-1 mm, 97 fused magnesia is 200 mesh, the particle size of alumina micropowder is 5 μm, the particle size of aluminum silicon composite ultrafine powder is 0.5 μm, ferrosilicon nitride is 200 mesh, metallic silicon is 325 mesh, and magnesium stearate and polyacrylamide are both powdered.

[0043] Examples 1 to 6

[0044] According to the ratio in Table 2, 96 fused magnesia, 97 fused magnesia, alumina powder, aluminum silicon composite ultrafine powder, sintering agent and self-flowing agent were weighed and mixed evenly to obtain anhydrous environmentally friendly hot patching materials. The obtained anhydrous environmentally friendly hot patching materials were sequentially recorded as 1# to 6#.

[0045] Table 2 Raw material ratios of the anhydrous environmentally friendly hot patching materials of Examples 1 to 6 (parts by mass)

[0046]

[0047]

[0048] Comparative Examples 1-2

[0049] The raw materials were weighed according to the ratio in Table 3 and mixed evenly to obtain the traditional asphalt hot patch material and the water-based environmentally friendly hot patch material.

[0050] Table 3 Raw material ratios of traditional asphalt hot patching material and water-based environmentally friendly hot patching material (mass fractions)

[0051]

[0052] In Table 3, modified asphalt is mixed with resin, high molecular polymer and other modifiers, and produced through a specific production process to produce asphalt with better high and low temperature performance. It not only retains the properties of asphalt, but also broadens the product's operating temperature and stability. The modified asphalt used in Table 3 is SBS modified asphalt.

[0053] Performance testing:

[0054] 1. The physical properties of the anhydrous environmentally friendly hot patching materials prepared in Examples 1 to 6 were tested in accordance with national standards GB / 3001-2007 and GB / 3002-2004. The results are shown in Table 4.

[0055] Table 4 Performance test results of the water-free environmentally friendly hot patching materials obtained in Examples 1 to 6

[0056] project condition 1# 2# 3# 4# 5# 6# <![CDATA[MgO+Al2O3%]]> / 88.28 87.62 87.89 88.32 87.92 88.32 Compressive strength / MPa 1450℃×3h 18.76 19.38 20.02 20.19 20.53 20.80 Flexural strength / MPa 1450℃×3h 7.42 7.83 8.26 8.28 8.41 8.65 Hot flow value 1250℃×0.5h 150 160 180 180 185 200

[0057] It can be seen from Table 4 that the water-free environmentally friendly hot patching material prepared by the present invention has high compressive strength and flexural strength and good hot fluidity.

[0058] 2. Repair experiments were conducted using the water-free environmentally friendly hot patching material prepared in Example 6 and the traditional asphalt hot patching material and water-based environmentally friendly hot patching material prepared in Comparative Examples 1 and 2. The furnace to be repaired was a steelmaking converter, and the area to be repaired was roughly the same, both 8m 2 The service life of the steelmaking furnace after repair was tested, and the hot self-flowing property, adhesion, sintering property, environmental protection, safety, operating performance and net steel performance of the three hot-patch materials were tested. The results are shown in Table 5.

[0059] Table 5 Performance evaluation results of different hot patching materials

[0060]

[0061] According to the data in Table 5, it can be seen that the water-free environmentally friendly hot patch material provided by the present invention has good self-leveling properties, short sintering time, long service life, and is superior to traditional asphalt hot patch materials in terms of environmental protection, safety and clean steel performance. It is also easy to operate, better than water-based hot patch materials, not prone to splashing, and safer than water-based hot patch materials.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A water-free environmentally friendly hot patching material, characterized in that: The invention is composed of the following components in parts by mass: 75-80 parts of 96 fused magnesia, 8-10 parts of 97 fused magnesia, 5-7 parts of alumina micropowder, 4-6 parts of aluminum silicon composite ultrafine powder, 1-5 parts of sintering agent, and 0.2-1.1 parts of self-flowing agent; The sintering agent is one or both of ferrosilicon nitride and metallic silicon; the self-flowing agent is one or both of magnesium stearate and polyacrylamide; the particle size of the aluminum-silicon composite ultrafine powder is 0.5-1.5 μm; the mass fraction of aluminum oxide in the aluminum-silicon composite ultrafine powder is 45-48%, and the mass fraction of silicon dioxide is 52-55%.

2. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The 96 fused magnesia is obtained by compounding a first 96 fused magnesia, a second 96 fused magnesia and a third 96 fused magnesia. The particle size of the first 96 fused magnesia is greater than 3 mm and less than or equal to 5 mm, the particle size of the second 96 fused magnesia is greater than 1 mm and less than or equal to 3 mm, and the particle size of the third 96 fused magnesia is greater than 0 and less than or equal to 1 mm. The mass ratio of the first 96 fused magnesia, the second 96 fused magnesia and the third 96 fused magnesia is 18~22:30~35:25~28.

3. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The mesh number of the 97 fused magnesia is 200 meshes.

4. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The particle size of the alumina powder is 1.5-5 μm.

5. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The mesh size of the ferrosilicon nitride is 200-325 meshes, and the mesh size of the metallic silicon is 200-325 meshes.

6. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The sintering agent includes ferrosilicon nitride and metallic silicon, and the mass ratio of the ferrosilicon nitride to metallic silicon is 2-3:2-1.

7. The water-free environmentally friendly hot patching material according to claim 1, characterized in that: The self-flowing agent comprises magnesium stearate and polyacrylamide, and the mass ratio of the magnesium stearate to the polyacrylamide is 3-4:2-1.

8. The method for preparing the anhydrous environmentally friendly hot patching material according to any one of claims 1 to 7, characterized in that: The following steps are involved: The water-free environmentally friendly hot patch material is obtained by mixing 96 fused magnesia, 97 fused magnesia, alumina fine powder, aluminum silicon composite ultrafine powder, a sintering agent and a self-flowing agent.

9. The method for using the anhydrous environmentally friendly hot patching material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Without stopping the furnace, the water-free environmentally friendly hot patching material according to any one of claims 1 to 7 is directly put into the steelmaking furnace to be repaired and sintered for 15 to 25 minutes.

Images