A kind of iron ditch castable for hot jacket repair of drop point and its using method

Abstract

The application discloses a baking-free iron ditch castable for hot sleeve repair of a falling iron point and a use method thereof. The castable bone powder material comprises the following components in percentage by mass: brown corundum aggregate 60-66%; wettable graphite 2-4%; special carbon black 0.16-0.2%; special alumina micropowder 10-14%; silicon carbide 0.1-1mm: 4-10%; silicon carbide powder 6-10%; boron carbide powder 0.2-0.4%; metal silicon powder 1-1.5%; explosion-proof fiber 0.08-0.12%; dense corundum powder 4-8%; and externally added silica sol 5.4-5.8%. At a construction site, the time for molten iron to contact the castable is delayed by smearing an aluminum-silicon carbide carbonaceous slurry combined with submicron SiO2 micropowder in a U-shaped mold, the castable is uniformly baked well, the innovative baking-free hot sleeve repair of the falling iron point is realized without curing and demolding, and the construction time is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of amorphous refractory, and particularly relates to a baking-free iron channel castable for hot sleeve repair of iron drop point and a use method thereof. BACKGROUND

[0002] The iron channel of the blast furnace casthouse is a necessary passage for the high-temperature molten iron to flow from the blast furnace tapping hole to the iron ladle or torpedo tank. The iron drop point of the main iron channel is subjected to severe erosion of high-temperature molten iron and slag for a long time. The erosion speed of the working lining at the iron drop point is significantly faster than that of the rear half of the main channel, which becomes the core factor restricting the service life of the whole iron channel. In order to improve the service efficiency of the whole main iron channel, the iron drop point area often needs to be repaired separately by hot sleeve. Since the material of the repair area has high requirements on the high-temperature performance of the castable, the domestic general-purpose corundum silicon carbide carbonaceous iron channel castable containing about 3% mass ball pitch combined with cement is used.

[0003] However, the time for the blast furnace to separately repair the iron drop point area by hot sleeve is usually very limited, and even the blast furnace is forced to make concessions to the hot sleeve repair of the iron drop point area at the expense of the tapping amount and the operation index of the blast furnace. Since the hot sleeve repair usually needs four indispensable links of pouring, curing, demolding and baking, how to greatly reduce the time for the hot sleeve repair of the iron drop point is a technical problem that has not been broken through by the iron front operation. Moreover, when the traditional iron channel castable is used for hot sleeve repair of the iron drop point, the volatilization of the pitch contained in the castable produces carcinogenic irritating gas, pollutes the air and adversely affects the health of the furnace front operators.

[0004] 201811417432.7 discloses an iron channel castable for long-life hot repair, which comprises, by mass percentage: brown corundum 56%-64%; silicon carbide 5%-13%; ball pitch 2%-3%; pure calcium aluminate cement 1.5%-2.5%; alumina powder 8%-12%; silica powder 1.5%-2.5%; silicon carbide powder 11%-13%; composite antioxidant 1%-2%; metal aluminum powder 0.1%-0.3%; anti-explosion fiber less than 0.1%; dispersing agent 0.2%-0.4%; and coagulant less than 0.08%. The scheme uses a new coagulant to make the metal aluminum powder in the iron channel castable produce hydrogen gas in advance, opens the exhaust hole at the time when the castable does not produce solidified strength, and cooperates with the appropriate metal aluminum powder and low-solubility anti-explosion fiber to ensure that the castable has excellent high-temperature use performance while meeting the construction conditions. However, since the cement is combined, the four indispensable links of pouring, curing, demolding and baking are needed, the construction time is long, and the pitch is not environmentally friendly.

[0005] 202110708755.7 discloses an ammonium ion stable type silicon sol combined iron runner castable, the composition is as follows in mass percentage: brown corundum 55-70%; silicon carbide 15-30%; ball pitch 1-3%; composite siliconized graphite 0.5-3%; alumina micropowder 5-10%; antioxidant 1-5%; wherein, additional ammonium ion stable type silicon sol 5-7wt%. The invention uses ammonium ion stable type silicon sol binder, which reduces the introduction of harmful impurities such as alkaline oxides as much as possible, but cannot achieve the explosion resistance of super sol. Although the castable is faster than the cement combined iron runner castable in construction speed, it still needs four indispensable links of casting, curing, demolding and baking, and the construction time is still long, and it contains pitch which is not environmentally friendly.

[0006] 201010185737.7 discloses an explosion-proof iron runner castable. It contains the following raw material components in weight percentage: fused tabular corundum 55-80%, silicon carbide 10-30%, soft clay 1-5%, pure calcium aluminate cement 2-5%, ultrafine powder 1-7%, explosion-proof agent 0.5-1.5%, and water reducing agent 0.05-0.15%. The explosion-proof agent is a mixture of aluminum powder, aluminum lactate, explosion-proof fiber, and boron carbide powder in a weight ratio of 1-2:2.5-4:1-2.5:2-4. The castable has no cracks after demolding and drying, and no explosion during baking. The safe explosion-proof temperature of the castable is increased from 500℃ to 800℃, which can meet the requirements of rapid construction and use of small and medium-sized single iron mouth blast furnace iron runner. The castable has a long service life, can improve the environment of the cast house, greatly reduce the labor intensity of workers, improve the quality of molten iron, and enhance the safety factor of the iron runner. Although the cement combined iron runner castable has improved explosion resistance, it still needs four indispensable links of casting, curing, demolding and baking, which takes a long time to construct and cannot achieve the effect of baking-free.

[0007] Therefore, how to research an environmentally friendly baking-free iron runner castable for hot sleeve repair of the falling iron point has become an important topic for several thousand iron runners in China. SUMMARY

[0008] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a baking-free iron runner castable for hot sleeve repair of the falling iron point and a use method. The castable has the characteristics of fast curing speed, good explosion resistance, environmental protection, no pollution, long service life, and realizes no curing, no demolding, and baking-free for hot sleeve repair of the falling iron point, which greatly reduces the construction time.

[0009] To solve the above technical problems, the present application adopts the following technical scheme:

[0010] The application provides a baking-free iron channel pouring material for hot repair of a falling iron point, which comprises bone powder and a silica sol binder.

[0011] The components of the bone powder are as follows in percentage by mass:

[0012] Among them:

[0013] The D90 of the special alumina powder is less than or equal to 4.5 microns; the main chemical components are as follows: Al2O3 is greater than or equal to 99.5wt%, and Na2O is less than or equal to 0.1wt%; the crystal diameter of the alumina primary crystal is controlled to be 0.45-0.55 microns, and the alpha phase conversion rate is greater than or equal to 95%.

[0014] The silica sol is prepared from elemental Si, and the average particle size is 9.5-11.5nm.

[0015] The anti-explosion fiber is a water-soluble polyvinyl alcohol fiber with a length of 5.5-6.5mm and a diameter of 16-18 microns.

[0016] According to the above scheme, the wettability graphite has a particle size of 0.1-0.5mm and a C content of greater than or equal to 80wt%, is obtained by changing the wettability of natural flake graphite by changing the wetting angle with water, and replaces the traditional ball pitch in the iron channel pouring material, so that the carbon content of the raw material can be increased, the oxidation resistance, high-temperature strength and explosion resistance of the pouring material can be enhanced, and the slag erosion speed of the rotary anti-sludge is reduced by nearly half compared with the traditional ball pitch.

[0017] According to the above scheme, in the silica sol, SiO2 is greater than or equal to 30%, Na2O is less than or equal to 0.35%, the PH value is 9.5-10.5, and the viscosity (25℃, mpa.s) is 4-5.

[0018] According to the above scheme, the brown corundum aggregate is smelted by a 7500kW tilting furnace, and the Al2O3 content is greater than or equal to 95wt%, the CaO content is less than or equal to 0.3wt%, the SiO2 content is less than or equal to 0.9wt%, the C content is less than or equal to 0.1wt%, the S content is less than or equal to 0.05wt%, and the bulk density is greater than or equal to 3.85g / cm 3 ; wherein the proportion of the particles with a particle size of 8-5mm, the particles with a particle size of 5-3mm, the particles with a particle size of 3-1mm and the particles with a particle size of 1-0.1mm is 20-24:16-20:12-16:6-12.

[0019] According to the above scheme, the particle size of the silicon carbide is 0.1-1mm, and the SiC content is greater than or equal to 98.5wt%, and the Fe2O3 content is less than or equal to 0.3wt%.

[0020] According to the above scheme, the SiC content in the silicon carbide powder is greater than or equal to 98%, and the fineness is less than or equal to 74um.

[0021] According to the above scheme, the special carbon black is N990R type from Germany.

[0022] According to the above scheme, the boron carbide powder content B4C≥94%, and the fineness is ≤45um.

[0023] According to the above scheme, the particle size of the metal silicon powder is ≤74um, and the Si content is ≥98.5%.

[0024] According to the above scheme, the dense corundum powder has a fineness of ≤74um, contains Al2O3≥98.5wt%, and Fe2O3≤0.3wt%.

[0025] A method for using the above baking-free iron channel castable for hot repair of iron falling points is provided, comprising the following steps:

[0026] 1) On site, mix the bone powder and silica sol evenly to obtain the baking-free iron channel castable;

[0027] 2) A layer of aluminum silicon carbide carbonaceous slurry combined with submicron SiO2 powder is applied to the inner wall of the U-shaped temporary mold in advance, and the mold is heated to evaporate the water in the slurry;

[0028] 3) After the heated U-shaped temporary mold in step 2) is placed on the main iron channel where the molten iron flows, the baking-free iron channel castable obtained in step 1) is poured, and after pouring is completed, demolding and baking are not required, and the repair of the iron falling point is completed.

[0029] According to the above scheme, in the aluminum silicon carbide carbonaceous slurry combined with submicron SiO2 powder, the water content is ≤10%, Al2O3≥60%, SiC≥18%, and the purity of the main components Al2O3+SiC+SiO2+C+Si+B4C≥98%.

[0030] According to the above scheme, the aluminum silicon carbide carbonaceous slurry combined with submicron SiO2 powder has the following components in mass percentage: dense corundum fine aggregate 22-44%; dense corundum powder 15-30%; alumina powder 6-10%; submicron SiO2 powder 9-11%; silicon carbide dust 20-25%; nano carbon black 3-5%; boron carbide powder 0.5-1%; metal silicon powder 1.5-2.5%; and dispersing agent 0.3-0.7%.

[0031] Preferably, the submicron SiO2 powder is high-purity silica powder with SiO2>99wt%, pH value less than 4, and volume average particle size less than 0.3 microns.

[0032] Preferably, the dispersing agent is a mixture of polyacrylic acid salt, polycarboxylic acid, and alumina powder, which is a high-efficiency composite water reducing agent.

[0033] According to the above scheme, in the step 2), the U-shaped temporary mold is made of a 10-14mm thick steel plate.

[0034] According to the above scheme, in the step 2), the thickness of the mud coating is 5-8mm.

[0035] According to the above scheme, in the step 2), the mold is heated to above 100℃ for standby. Preferably, the temperature is 100-500℃.

[0036] According to the above scheme, in the step 3), the iron channel castable is one ton per package, and one ton per package is stirred.

[0037] According to the above scheme, in the step 1), three portions of the non-baking iron channel castable are configured. In the first portion of the iron channel castable, 12-15% of the silicon sol is added to the bone powder material as the first package of the castable (one ton per package). In the second portion of the iron channel castable, 8-10% of the silicon sol is added to the bone powder material as the second package of the castable. In the third portion of the iron channel castable, 5.4-5.8% of the silicon sol is added to the bone powder material. In the step 3), when the non-baking iron channel castable obtained in the step 1) is started to be poured, the first portion of the iron channel castable is added first, then the second portion of the iron channel castable is added, and finally the third portion of the iron channel castable is added until the pouring is completed.

[0038] The application provides a non-baking iron channel castable for hot repair of a falling iron point.

[0039] The application improves the explosion resistance of the castable by selecting the silicon sol + selected polyvinyl alcohol fiber + special alumina powder combination, and provides a material solution for accelerating the hot sleeve repair speed of the falling iron point. Among them: the selected spherical silica sol with good sphericity and an average particle size of about 10nm has higher drying strength and better explosion resistance when added to the castable; in combination with the selected polyvinyl alcohol fiber, the explosion resistance temperature of the castable can be significantly improved; at the same time, the special alumina powder reduces the liquid addition amount, improves the strength and density of the castable, and can also adjust the curing time of the castable. At the same time, the application uses wettable graphite to replace the traditional ball pitch in the iron channel castable, which increases the content of carbonaceous raw materials, enhances the oxidation resistance, high temperature strength, explosion resistance and slag resistance of carbon in the castable, and also reduces the liquid addition amount, and enhances the density of the castable.

[0040] The application adopts a special U-shaped temporary mold, and a layer of sub-micron SiO2 micro powder combined with aluminum silicon carbide carbon slurry is coated in the mold. Because the sub-micron SiO2 micro powder is obviously acidic when the pH value is about 3.5, which can corrode the mold, the slurry can firmly become an integral whole with the mold, avoiding the slurry from falling off due to baking the mold and pouring vibration. During pouring, the groove wall and the mold have high temperature, the pouring material solidifies quickly when heated, and a large amount of gas channels are generated by the rapid melting of polyvinyl alcohol fiber, which not only helps the water to be discharged, but also quickly transmits the heat of the groove wall and the mold to the inside of the pouring material. After the pouring material is poured, most of the pouring surface has been solidified and quickly discharges water vapor. After the iron starts to be poured, the high-temperature molten iron cannot immediately contact the pouring material which has been basically solidified due to the blocking of the aluminum silicon carbide carbon slurry and the mold, and the pouring material is uniformly baked. When the molten iron completely contacts the pouring material, the pouring material has been completely solidified and baked thoroughly, and at this time, the pouring material is in the high-temperature strength time of sol combined, so the ability of the pouring material to resist slag and iron erosion at the iron dropping point is greatly improved.

[0041] Further, when pouring the iron dropping point, the first tank of pouring material silicon sol binder is added by 12-15%, the second tank of pouring material silicon sol binder is added by 8-10%, and the silicon sol binder in the subsequent pouring material is added by 5.4-5.8% normally. Because when the powder content in the pouring material is too high, the combined gap or "point combination" caused by the rapid solidification of the combined pouring material after being heated leads to the falling off, and the hot groove surface is difficult to form effective surface combination; therefore, the powder content in the first tank of pouring material is reduced to slow down the solidification speed, the powder content in the second tank is gradually increased, and the powder content in the subsequent pouring material is continuously increased according to the normal ratio, which is beneficial to the full "surface combination" with the groove lining, ensures the use effect of the hot pouring, and improves the stability of the pouring quality.

[0042] Compared with the prior art, the application has the following beneficial effects:

[0043] 1. The application provides a baking-free iron groove pouring material for iron dropping point hot repair, which improves the explosion resistance, strength, density and oxidation resistance of the pouring material by selecting silicon sol + selected polyvinyl alcohol fiber + special aluminum oxide powder + wettable graphite, completely solves the problem of environmental pollution caused by the volatilization of asphalt contained in the traditional iron groove pouring material, avoids the adverse effects of carcinogenic irritating gas on the health of furnace operators, is green and environmentally friendly, and has a wide application prospect.

[0044] 2. The application provides a use method of a baking-free iron channel castable for hot repair of a falling iron point, which delays the time of molten iron contacting the castable by smearing an aluminum silicon carbide carbonaceous slurry combined with submicron SiO2 powder in a U-shaped mold, has a good uniform baking effect on the castable, and realizes baking-free hot repair of the falling iron point without curing and demolding, greatly reduces the construction time, and breaks through the technical bottleneck of baking-free iron channel castable which cannot be broken through for a long time. DETAILED DESCRIPTION

[0045] In order to better understand the application, the content of the application is further illustrated below in combination with examples, but the content of the application is not limited to the examples only.

[0046] In the following examples, the indexes of each raw material are as follows:

[0047] The brown corundum aggregate is smelted by a 7500-kilowatt tilting furnace, and Al2O3 is greater than or equal to 95wt%, CaO is less than or equal to 0.3wt%, SiO2 is less than or equal to 0.9wt%, C is less than or equal to 0.1wt%, and S is less than or equal to 0.05wt%, and the bulk density is greater than or equal to 3.85g / cm 3 The proportions of the particles with a particle size of 8-5mm, 5-3mm, 3-1mm and 1-0.1mm are 22:18:14:8-12.

[0048] The silicon carbide 0.1-1mm contains SiC greater than or equal to 98.5wt% and Fe2O3 less than or equal to 0.3wt%.

[0049] The wettability graphite has a particle size of 0.1-0.5mm, C is greater than or equal to 80wt%, and is a WFGS-95D type from Luoyang Zhushi Kiln Industry Co., Ltd.

[0050] The special alumina powder is a microcrystalline phase inversion alumina powder, D90 is less than or equal to 4.5 microns, the main chemical components are Al2O3 greater than or equal to 99.5wt% and Na2O less than or equal to 0.1wt%, the crystal diameter of the original crystal of the alumina is controlled to be 0.45-0.55 microns, and the alpha phase conversion rate is greater than 95%. The alumina powder has excellent filling performance and activity through the microcrystalline phase inversion process, the drying strength is increased by 30%-50% compared to domestic ordinary alumina powder, the activity is very stable, has better water-reducing performance, good fluidity and strength development.

[0051] The special carbon black is a N990R type from Germany.

[0052] The SiC content in the silicon carbide powder is greater than or equal to 98%, and the fineness is less than or equal to 74um.

[0053] The B4C content in the boron carbide powder is greater than or equal to 94%, and the fineness is less than or equal to 45um.

[0054] The particle size of the metal silicon powder is ≤74 μm, and the Si content is ≥98.5%.

[0055] The polyvinyl alcohol fiber is a water-soluble fiber with good dispersibility at 80°C, 5.5-6.5 mm long, 16-18 microns in diameter, and good anti-explosion performance.

[0056] The dense corundum powder has a fineness of ≤74 um, contains Al2O3≥98.5 wt%, and Fe2O3≤0.3 wt%.

[0057] The silicon sol is prepared from elemental Si, contains SiO2≥30%, Na2O≤0.35%, has a pH value of 9.5-10.5, a viscosity (25°C, mpa.s) of 4-5, and an average particle size of 9.5-11.5 nm. The silicon sol prepared from elemental Si has a relatively uniform particle size distribution and a better spherical shape, and the particle size is controlled at about 10 nm, so that the silicon sol has higher drying strength and better anti-explosion performance when added to the castable.

[0058] The sub-micron SiO2 micro-powder combined aluminum silicon carbide carbon slurry is obtained according to the application number 202010047107.7, and the specific components and their mass percentages are as follows: dense corundum aggregate 44%; alumina micro-powder 6%; high-purity silicon dioxide micro-powder 9.7% (high-purity silicon dioxide micro-powder, SiO2>99 wt%, pH value less than 4, volume average particle size less than 0.3 microns); silicon carbide dust 20%; nano carbon black 3%; dispersing agent 0.5% (dispersing agent is a mixture of polyacrylate, polycarboxylic acid and alumina powder); metal silicon powder 1.5%; boron carbide powder 0.5%; dense corundum powder 15%. The raw materials are weighed and fully mixed according to the above ratio; then two-thirds of the slurry is fully stirred and mixed with 8.8% of water to a very dilute state, and the remaining one-third of the slurry is slowly added to the mixed material to a better construction state.

[0059] Example 1

[0060] An iron channel castable for hot sleeve repair of a falling iron point without baking, comprising a bone powder and a silicon sol binder; wherein:

[0061] The components of the bone powder and their mass percentages are as follows:

[0062]

[0063] The raw materials are weighed and fully mixed according to the above ratio; an additional 5.4% of the bone powder is stirred and mixed with the silicon sol to obtain an iron channel castable sample without baking.

[0064] The performance of the no-baking iron channel castable sample prepared in this embodiment for hot repair of the drop point is detected, and the results are shown in Table 1. The performance detection method adopted is in accordance with the current national standard or industry standard, and the detection results obtained are the average detection results of three times (hereinafter the same).

[0065] Table 1. Performance detection results of the no-baking iron channel castable sample prepared in Example 1 for hot repair of the drop point

[0066]

[0067] In field use, three no-baking iron channel castable samples are prepared. In the first no-baking iron channel castable sample, 15% of the silicon sol is added to the bone meal by mass, which is used as the first tank castable (one ton per tank). In the second no-baking iron channel castable sample, 10% of the silicon sol is added to the bone meal by mass, which is used as the second tank castable. In the third no-baking iron channel castable sample, 5.4% of the silicon sol is added to the bone meal by mass.

[0068] Firstly, a U-shaped temporary mold is made of a 12mm thick steel plate. The inner wall of the mold is coated with an 8mm aluminum carbide silicon carbonaceous mud combined with sub-micron SiO2 powder in advance, and the mold is placed on the branch channel or the slag channel and heated to dry to remove water. When repairing the drop point, the slag iron is cleaned first, then the above-mentioned heated U-shaped temporary mold is placed, and the no-baking iron channel castable is poured. First, the first no-baking iron channel castable is added, then the second no-baking iron channel castable is added, and finally the third no-baking iron channel castable is added until the pouring is completed. After pouring, demolding is not required, and the iron can be poured without baking. Compared with the traditional iron channel castable, the construction time of the iron channel castable obtained in this embodiment is shortened by 60%, and the service life is improved by 20%.

[0069] Example 2

[0070] A no-baking iron channel castable for hot repair of a drop point, comprising a bone meal and a silicon sol binder; wherein:

[0071] The components of the bone meal and the mass percentage thereof are as follows:

[0072]

[0073]

[0074] The raw materials are weighed according to the above-mentioned ratio and fully mixed; 5.6% of the silicon sol is added to the bone meal by mass to prepare a no-baking iron channel castable sample.

[0075] The performance of the no-baking iron channel castable sample prepared in this embodiment for hot repair of the drop point is detected, and the results are shown in Table 2. The performance detection method adopted is in accordance with the current national standard or industry standard, and the detection results obtained are the average detection results of three times (hereinafter the same).

[0076] Table 2. Performance test results of the no-baking iron runner castable sample prepared in Example 2 for hot repair of a falling iron point

[0077]

[0078] In field use, three no-baking iron runner castables are prepared. In the first iron runner castable, 12% of the silicon sol by mass of the bone meal is added, as the first tank castable (one ton per tank); in the second iron runner castable, 9% of the silicon sol by mass of the bone meal is added; and in the third iron runner castable, 5.6% of the silicon sol by mass of the bone meal is added.

[0079] First, a U-shaped temporary mold is made of a 12 mm thick steel plate, the inner wall of which is coated with a 6.5 mm aluminum carbide silicon carbonaceous slurry combined with sub-micron SiO2 powder in advance, and the mold is placed on a branch channel or a slag channel and heated to dry to remove moisture. When repairing the falling iron point, the slag iron is cleaned first, and then the above-mentioned heated U-shaped temporary mold is placed, and the no-baking iron runner castable is poured. First, the first iron runner castable is added, then the second iron runner castable is added, and finally the third iron runner castable is added until the pouring is completed. After pouring is completed, no demolding is required, and no baking is required to have the conditions for tapping.

[0080] Example 3

[0081] A no-baking iron runner castable for hot repair of a falling iron point, comprising a bone meal and a silicon sol binder; wherein:

[0082] The components of the bone meal and the mass percentage thereof are as follows:

[0083]

[0084]

[0085] The raw materials are weighed according to the above-mentioned ratio and fully mixed; 5.8% of the silicon sol by mass of the bone meal is added and stirred uniformly to prepare the no-baking iron runner castable sample.

[0086] The no-baking iron runner castable sample prepared in this example for hot repair of a falling iron point is subjected to performance testing, and the results are shown in Table 3. The performance testing methods used are in accordance with the current national standards or industry standards, and the test results obtained are the average test results of three times (hereinafter the same).

[0087] Table 3. Performance test results of the no-baking iron runner castable sample prepared in Example 3 for hot repair of a falling iron point

[0088]

[0089] In field use, three portions of the no-baking iron runner castable are prepared. In the first portion of the iron runner castable, 13.5% of the silicon sol by mass of the bone meal is stirred to serve as the first tank castable (one tank per ton); in the second portion of the iron runner castable, 8% of the silicon sol by mass of the bone meal is stirred to serve as the second tank castable; and in the third portion of the iron runner castable, 5.8% of the silicon sol by mass of the bone meal is stirred.

[0090] First, a U-shaped temporary mold is made of a 12 mm thick steel plate, the inner wall of which is coated with a 5 mm aluminum carbide silicon carbonaceous mud combined with sub-micron SiO2 powder in advance, and the mold is placed on a runner or a slag runner and heated to dry to remove moisture. When repairing a falling iron point, the slag iron is cleaned first, and then the U-shaped temporary mold that has been heated is placed on the runner, and the no-baking iron runner castable is poured. First, the first portion of the iron runner castable is added, then the second portion of the iron runner castable is added, and finally the third portion of the iron runner castable is added until the pouring is completed. After pouring is completed, demolding is not required, and the iron runner castable has the conditions for tapping without baking.

[0091] Example 4

[0092] A no-baking iron runner castable for repairing a falling iron point by hot sleeving, comprising a bone meal and a silicon sol binder; wherein:

[0093] The components of the bone meal and the mass percentage thereof are as follows:

[0094]

[0095] The raw materials are weighed according to the above-mentioned proportions and fully mixed; 5.6% of the silicon sol by mass of the bone meal is stirred to obtain a no-baking iron runner castable sample.

[0096] The no-baking iron runner castable sample for repairing a falling iron point by hot sleeving prepared in this example is subjected to performance detection, and the results are shown in Table 4. The performance detection methods used are in accordance with the current national standards or industry standards, and the detection results obtained are the average detection results of three times (hereinafter the same).

[0097] Table 4. Performance detection results of the no-baking iron runner castable sample for repairing a falling iron point by hot sleeving prepared in Example 4

[0098]

[0099] In field use, three portions of the no-baking iron runner castable are prepared. In the first portion of the iron runner castable, 13.5% of the silicon sol by mass of the bone meal is stirred to serve as the first tank castable (one tank per ton); in the second portion of the iron runner castable, 8% of the silicon sol by mass of the bone meal is stirred to serve as the second tank castable; and in the third portion of the iron runner castable, 5.8% of the silicon sol by mass of the bone meal is stirred.

[0100] The U-shaped temporary mold is made of 12mm thick steel plate, the inner wall of the mold is coated with 6.5mm sub-micron SiO2 micro powder combined with aluminum silicon carbide carbon slurry in advance, and the mold is placed on the branch ditch or slag ditch and heated to dry to remove moisture. When repairing the fallen iron point, the slag iron is cleaned first, then the U-shaped temporary mold is placed on the heated mold, and the baking-free iron channel casting material is poured. First, the first portion of the iron channel casting material is added, then the second portion of the iron channel casting material is added, and finally the third portion of the iron channel casting material is added until the pouring is completed. After pouring is completed, demolding is not required, and baking is not required to have the iron tapping condition.

[0101] The above results show that the baking-free iron channel casting material for hot repair of the fallen iron point has the characteristics of short construction time, high strength after burning, high thermal strength, environmental protection and no pollution.

[0102] Obviously, the above examples are only examples for clearly illustrating, but not limit the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments are not required and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method of using a bake-free iron channel castable for hot-spot repair of a fallen iron, characterized in that, The iron runner castable comprises a bone powder and a silica sol binder; components of the bone powder are as follows in percentage by mass: brown corundum aggregate 60-66%, wettable graphite 2-4%, special carbon black 0.16-0.2%, special alumina micropowder 10-14%, silicon carbide 0.1-1mm 4-10%, silicon carbide powder 6-10%, boron carbide powder 0.2-0.4%, metallic silicon powder 1-1.5%, explosion-proof fiber 0.08-0.12%, dense corundum powder 4-8%, and silica sol 5.4-5.8% added externally; wherein: The special alumina micropowder has D90≤4.5 microns, Al2O3≥99.5wt%, Na2O≤0.1wt%, the crystal diameter of the alumina primary crystal is controlled to be 0.45-0.55 microns, and the alpha phase conversion rate is above 95%; the silica sol is prepared from elemental Si and has an average particle size of 9.5-11.5nm; the explosion-proof fiber is 80℃ water-soluble polyvinyl alcohol fiber, 5.5-6.5mm long and 16-18 microns in diameter; The use method comprises the following steps: 1) on site, mix the bone powder and the silica sol uniformly to obtain the baking-free iron runner castable; 2) apply a layer of alumina-silicon carbide carbonaceous slurry mixed with submicron SiO2 micropowder on the inner wall of a U-shaped temporary mold in advance, and heat the mold to evaporate the water in the slurry; 3) after the heated U-shaped temporary mold in step 2) is placed on the main iron runner at the iron drop point where the molten iron flows, start pouring the baking-free iron runner castable obtained in step 1), and after pouring is completed, no demolding or baking is needed, and the iron drop point repair is completed.

2. The method of use of claim 1, wherein, The alumina-silicon carbide carbonaceous slurry mixed with submicron SiO2 micropowder has water addition amount ≤10%, Al2O3≥60%, SiC≥18%, and the purity of the main components Al2O3+SiC+SiO2+C+Si+B4C≥98%.

3. The method of use of claim 1, wherein, In step 2), the U-shaped temporary mold is made of a 10-14mm thick steel plate; the slurry coating has a thickness of 5-8mm.

4. The method of use of claim 1, wherein, In step 1), three portions of the baking-free iron runner castable are configured; in the first portion of the iron runner castable, 12-15% of the silica sol is added to the bone powder as the first tank castable; in the second portion of the iron runner castable, 8-10% of the silica sol is added to the bone powder as the second tank castable; and in the third portion of the iron runner castable, 5.4-5.8% of the silica sol is added to the bone powder; in step 3), when the pouring of the baking-free iron runner castable obtained in step 1) is started, the first portion of the iron runner castable is added first, then the second portion of the iron runner castable is added, and finally the third portion of the iron runner castable is added until the pouring is completed.

5. The method of use of claim 1, wherein, The wettable graphite has a particle size of 0.1-0.5mm and C≥80wt%.

6. The method of use of claim 1, wherein, In the silica sol, SiO2≥30%, Na2O≤0.35%, pH value 9.5-10.5, and viscosity at 25℃ 4-5 mpa.s.

7. The method of use of claim 1, wherein, The brown corundum aggregate contains Al2O3≥95wt%, CaO≤0.3wt%, SiO2≤0.9wt%, C≤0.1wt%, S≤0.05wt%, and the bulk density is ≥3.85g / cm 3 ; wherein the proportion of the particles with a particle size of 8-5mm: the particles with a particle size of 5-3mm: the particles with a particle size of 3-1mm: the particles with a particle size of 1-0.1mm is 20-24:16-20:12-16:6-12; the dense corundum powder fineness is ≤74um; and the Al2O3 content is ≥98.5wt%, and the Fe2O3 content is ≤0.3wt%.

8. The method of use of claim 1, wherein, The silicon carbide 0.1-1mm particle size is 0.1-1mm, wherein SiC is greater than or equal to 98.5% by weight, and Fe2O3 is less than or equal to 0.3% by weight; the silicon carbide powder has a SiC content greater than or equal to 98% and a fineness of less than or equal to 74um; and the boron carbide powder has a B4C content greater than or equal to 94% and a fineness of less than or equal to 45um.

9. The method of use of claim 1, wherein, The special carbon black is N990R produced in Germany; and the particle size of the metal silicon powder is less than or equal to 74um, and the Si content is greater than or equal to 98.5%.

Images