JP2018039939A - Coke oven blast furnace bottom repairing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blast furnace bottom repairing material forming a construction body which is smooth and parallel without damaging a repaired surface of a blast furnace bottom of a coke oven, having high adhesive strength and excellent in durability.SOLUTION: There is provided a blast furnace bottom repairing material used for flame coating method by using a mixture of a SiO2 fire refractory powder, a metal powder as a burning material and a quicklime powder as a main raw material and spraying the same together with oxygen to repair a surface to be repaired. Content of the quicklime powder is 22 to 40 mass% based on total amount of the main raw material, particle diameter thereof is 5 mass% or less of particles with more than 355 μm, 7 to 20 mass% of particles with 75 μm or less and the balance particles with 75 to 355 μm, mass percentage of a CaO component contained in the quicklime powder (purity) is generally 90 to 99% or more. There is provided a blast furnace bottom repairing material where SiO2 fire refractory powder is 40 to 68 mass% based on total amount of the main raw material and the metal powder is 10 to 20 mass% based on total amount of the main raw material when metal silicon powder is used.SELECTED DRAWING: None

Description

  The present invention relates to a repair material for a furnace bottom of an industrial kiln, and more particularly to a powder repair material for melting a refractory powder using oxidation reaction heat of a metal powder.

  A coke oven is a furnace for producing coke by carbonizing coal. The size of the carbonization chamber of the coke oven is about 5 m in height, about 15 m in length, and 45 to 50 cm in width, and both ends thereof, that is, 5 m in height and 45 to 50 cm in width are sealed with a coke oven lid. . When the dry distillation of coal is completed, the furnace lids on both sides are released, the coke is pushed from one side by an extruder, and the coke is taken out from the other end. Then, the furnace lid is closed, fresh coal is charged and dry distillation is performed. This cycle is performed about once a day.

  The bottom of the coke oven has a flat plate shape with a width of 45 to 50 cm and a length of about 15 m.

  The bottom of the coke oven tends to wear out due to the effect of shear stress applied during coke extrusion, or spalls due to a sudden temperature change or impact during charging of the raw material coal. When it becomes larger, resistance at the time of extrusion of coke increases, and in order to avoid a situation where it cannot be pushed out (called clogging), it is operated while repeating repairs using a short time between operations.

  Techniques for repairing the bottom of the furnace while continuing the operation include a thermal spray repair method, a dry method in which the powder repair material is directly repaired, and a wet method in which the powder repair material is mixed with water for repair.

  As a thermal spray repair method, a thermal spray method using a metal oxidation exothermic reaction is generally used in recent years. For example, Patent Documents 1 to 3 describe a thermal spray material in which a mixture of metal powder (combustion agent) and refractory powder is transported with oxygen and sprayed on a high-temperature repair surface. The sprayed mixture forms a refractory composition by an oxidative exothermic reaction of the metal powder caused by heat received from the repair surface and melts and adheres to the repair surface.

  The dry method is described in, for example, Patent Document 4, and a repair material containing two kinds of fluxes of powdered frit and a granular low melting point compound in a powder mainly composed of silica and alumina at 350 ° C. It is described as a repairing method in which the material is flattened horizontally and flatly after being laid in the concave portion of the surface of the refractory material of the carbonization chamber hearth at 600 ° C.

  The wet method is described in, for example, Patent Document 5 and increases strength by mixing a frit, silica fine powder, and phosphate with a refractory aggregate such as fused alumina and kneading it with water to form a slurry. It is described to suppress wear.

  In general, since the operating temperature of the coke oven is 900 ° C. to 1300 ° C., a silica brick having a large thermal expansion coefficient from room temperature to about 600 ° C. but having a thermal expansion coefficient of almost zero at 700 ° C. or higher is used. Due to the characteristics of such silica bricks, if the surface temperature falls sharply, it will be cracked and damaged by thermal shock. Therefore, it is preferable that the repair is performed hot so as not to lower the surface temperature of the brick, and the thermal spraying method is widely used as a kind of hot repair.

JP 61-275170 A Patent No. 4464804 JP 2009-120406 A JP 2007-145890 A JP 2004-168586 A

  The above-mentioned materials used for conventional coke oven bottom repair are not sufficient to satisfy all the above-mentioned various characteristics required for coke oven bottom repair materials. In particular, in coke oven furnace bottom repair, it is desirable that the surface after the repair is as horizontal as possible and does not form significant irregularities.

  The thermal spray material disclosed in Patent Document 1 desirably includes a welded layer having a material having a chemical composition similar to that of a refractory substrate. In the case of the bottom of a coke oven, it becomes siliceous. In the case of thermal spray material mainly composed of siliceous material, the melting point is not sufficiently low compared to the temperature at the time of thermal spraying, and the composition becomes highly viscous, so it is not smooth and difficult to finish horizontally. Not suitable for.

  Moreover, since the thermal spray material which patent document 2 discloses is a thermal spray material for the furnace wall repair use which is a perpendicular | vertical surface, it has the design which hold | maintains to an adhesion site | part after adhering to a furnace wall. Therefore, when the bottom of the furnace is sprayed with the same material, the material adhering to the sprayed portion is fixed on the spot, and it is not smooth and level, so it is not suitable for repairing the bottom of the furnace.

Patent Document 4 discloses that a powder repair material for a coke oven carbonization chamber hearth disclosed in Patent Document 4 is cooled to 350 ° C. to 600 ° C. and spread in a recess, and then applied to level and flat. Although this method can shorten the construction time itself, it is necessary to wait until it is allowed to cool, and it is not suitable for repair in a limited time between operations, and the center of the kiln is released from 350 ° C to 600 ° C. When it is cold, the vicinity of the kiln becomes 200 ° C. or lower, and the silica brick rapidly contracts, resulting in a crack, which is damaged rather than repaired. In addition, although it is described in the examples that melting is performed at 900 ° C., the melting point of the construction body is too low because it may be 1000 ° C. or more in actual operation, and when it peels off with the coke that is pushed out. Conceivable. In addition, it is considered that sufficient adhesive strength is necessary to withstand the shear stress during extrusion, but Patent Document 4 describes that the adhesive strength is a maximum of 203 kgf with respect to an adhesive area of 36 cm ² . The adhesive strength when divided by the adhesive area is 0.55 MPa, which is not sufficient.

  The refractory for coke oven hearth disclosed in Patent Document 5 makes it possible to smooth the hearth by pouring slurry-like repair material into the damaged part of the coke oven hearth, but moisture evaporates. By doing so, if the silica brick at the bottom of the furnace is deprived of heat and cooled down to 300 ° C. or less, the silica brick rapidly contracts, which may cause a crack and may be damaged.

  The present invention has been proposed in view of the above-mentioned conventional circumstances, and can form a smooth and horizontal construction body without damaging the work surface, and has a high adhesive strength and excellent durability. The purpose is to provide repair materials.

  The present invention is premised on a furnace bottom repair material used in a thermal spraying method in which a repaired surface is repaired by spraying together with oxygen using a mixture of a refractory powder of SiO 2, metal powder and quicklime powder as a main raw material.

  The content of the quicklime powder is 22 to 40% by mass with respect to the total amount of the main raw material, and the particle diameter is 5% by mass or less for particles larger than 355 μm and 75 μm or less for the whole furnace bottom repair material. 7 to 20% by mass, and the balance is 75 to 355 μm. The mass ratio (purity) of the CaO component contained in the quicklime powder is generally 90 to 99% or more.

  The SiO2 refractory powder is 40 to 68 mass% with respect to the total amount of the main raw material, and the metal powder is 10 to 20 mass with respect to the total amount of the main raw material when metal silicon powder is used. %.

  Furthermore, as an ignition accelerator, a metal powder having a function of assisting an initial amount of heat necessary for the oxidation reaction of the metal silicon powder can be added. The metal powder is 0.1 to 1.5% by mass based on the total amount of the main raw material. As such a metal powder, for example, iron powder, manganese powder, vanadium powder, magnesium powder, titanium powder, or a powder of these alloys can be preferably used. These metal powders may be used alone or in combination of two or more.

  In addition, as a combustion auxiliary agent, a metal oxide having a function of supplying oxygen during combustion of the furnace bottom repair material to oxidize metal silicon powder as a combustion agent on the work piece is used with respect to the total amount of the main raw material. Further, 0.3 to 2.0% by mass can be further blended as an outer shell. Examples of such metal oxides include transition metal oxides, particularly first transition metal oxides (scandium oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, oxidation Copper) and alkaline earth metal peroxides (lithium peroxide, calcium peroxide, magnesium peroxide, strontium peroxide, barium peroxide) can be preferably used. In addition, these metal oxides may be used alone or in combination of two or more.

  According to the present invention, it is possible to provide a furnace bottom repair material that can form a smooth and horizontal construction body without damaging the work surface, and has high adhesive strength and excellent durability.

<Confirmation test>
Thermal spraying type repair method is adopted as a method that can repair the furnace bottom without cooling. Furthermore, as a characteristic necessary for the furnace bottom repair, the furnace bottom is required to be smooth and horizontal after construction. For this reason, it is necessary to give the characteristic that the liquid becomes a surface close to a free surface when the thermal spray material melts and spreads. Therefore, by applying quick lime powder containing CaO with high purity to the SiO2 refractory aggregate raw material, the melting point is lowered and the viscosity at the time of melting is reduced.

  First of all, quick lime powder with a particle size of 75 μm or less is applied, considering that it reacts quickly and favors viscosity reduction, and a test is performed to gradually increase the content. Up to a content of 20% by mass is retained at the adhesion site and melted. I confirmed that it did not spread. This coincides with the fact that the thermal spray material containing 20% by mass of the calcia powder (CaO ratio of 96.97%) of the example of Patent Document 2 is established as a repair material for a furnace wall having a vertical surface.

  Further, it was found that when the content was increased, the viscosity decreased when the content was 22% by mass or more and 40% by mass or less, and when the content was more than 40% by mass, it was not melted and spread again. Moreover, when it exceeded 20 mass%, the continuity of combustion fell remarkably and it did not become what can be constructed satisfactorily. This is presumably because the melting endotherm per unit time increases due to the reaction between the SiO2 refractory aggregate and quicklime powder, and the melting proceeds rapidly, and the supply of heat for continuing combustion is insufficient.

  Therefore, in order to moderately delay the reaction between the SiO2 refractory aggregate and the quicklime powder, a test was performed in which the quicklime powder was coarsened and applied, and the continuity of combustion was not impaired while the viscosity decreased. It came to specify content and a particle diameter.

<Embodiment>
(principle)
The furnace bottom repair material according to the present invention is characterized by a mixture of SiO2 refractory powder, metal powder and quicklime powder (hereinafter, a mixture of SiO2 refractory powder, metal powder and quicklime powder is referred to as a main raw material). In order to control, various trace amounts of additives are added.

  The melting points of SiO 2 and CaO are 1650 ° C. and 2850 ° C. respectively, but when it becomes a calcium silicate mineral, the melting point decreases to 1550 ° C. or less at a composition of 45% by mass to 65% by mass, depending on the composition. The melting point drops to near. In addition, introduction of Ca ions into the SiO2 network leads to a decrease in viscosity at high temperatures. Therefore, by adjusting the CaO ratio in the melt at the time of thermal spraying to be about 45 mass% to about 65 mass%, a viscosity reducing effect can be obtained, and a smooth and horizontal construction body can be obtained by melting and spreading. .

  However, in the construction of the furnace bottom repair material according to the present invention, the SiO2 component is generated by the oxidation reaction of metal silicon, or some of the refractory aggregate particles of SiO2 rebound, so the CaO ratio in the main raw material is Even if it is 45 mass% to 65 mass%, it does not correspond with the CaO ratio in a melt. Therefore, the content of quicklime powder in the main raw material in which the CaO in the melt is 45% by mass to 65% by mass was specified by investigating the composition after actual construction.

  From the test results, the content of quicklime powder in the main raw material is preferably 22% by mass to 40% by mass. More preferably, it is 26 mass% to 36 mass%.

  The particle diameter of the quicklime powder is preferably 5% by mass or less of particles larger than 355 μm, 7 to 20% by mass of particles of 75 μm or less, and the remaining particles of greater than 75 μm and 355 μm or less in the entire furnace bottom repair material. More preferably, particles larger than 355 μm are 1.0% by mass or less, and particles of 75 μm or less are 10 to 17% by mass. When the blending amount of the quicklime powder having a particle size larger than 355 μm is increased, the reaction with the SiO 2 -based refractory aggregate particles does not proceed and the meltability is lowered. A quick lime powder having a particle size of 75 μm or less is also less than 7% by mass because the reaction with the SiO 2 -based refractory aggregate particles is delayed and the meltability is lowered.

  On the other hand, when the lime powder having a particle size of 75 μm or less exceeds 20% by mass, the reaction with the SiO 2 -based refractory aggregate particles is too fast, and the amount of melt endotherm per unit time increases and combustion continues. This is not preferable because the supply of the amount of heat is not in time, the continuity of combustion is remarkably lowered, and the construction cannot be satisfied satisfactorily. The mass ratio (purity) of the CaO component contained in the quicklime powder is generally 90 to 99% or more, and quicklime with a purity of 96% was used in this test.

  Hereinafter, components other than quicklime will be described in detail.

(Fireproof powder)
As described above, the furnace floor repair material according to the present invention is mainly composed of a mixture of SiO2 refractory powder, metal powder and quicklime powder. As the SiO2 refractory powder, silica, silica brick powder, fused silica, or the like can be used depending on the application. Although not particularly limited, the maximum particle size of the refractory powder is preferably 2000 μm or less. If the maximum particle size is larger than 2000 μm, large particles will rebound during construction, making it difficult to adhere to the work piece and lowering the thermal spraying efficiency.

(Metal powder)
In the furnace bottom repair material according to the present invention, a metal powder as a combustion agent is blended. A combustion agent turns into an oxide which forms the binder phase which couple | bonds the above-mentioned refractory powder after combustion. For example, when the work object to be repaired is made of silica brick mainly composed of SiO2, metal silicon powder can be used as the combusting agent.

  The addition amount of the metal silicon powder is 10% by mass or more and 20% by mass or less, and preferably 13% by mass or more and 17% by mass or less with respect to the total amount of the main raw material.

  If the amount added is less than 10% by mass, the combustion reaction becomes weak, and the continuity of combustion and the adhesion to the workpiece are remarkably deteriorated. On the other hand, if the amount added exceeds 20% by mass, the amount of heat generated by combustion increases and the temperature becomes too high. As a result, when the furnace bottom damaged part is constructed, the nozzle tip is overheated, so that the reaction starts at the nozzle tip and the construction is interrupted, so that the furnace bottom repair cannot be satisfactorily performed. The mass ratio (Si purity) of the metal Si component contained in the metal silicon powder is not limited, but generally 90% to 98% or more is used.

  As for the particle diameter of the metal powder, it is preferable that 75 μm or more is 5 mass% or less, 20 μm or less is 3 to 14 mass%, and the remainder is more than 20 μm and less than 75 μm in the entire furnace bottom repair material. More preferably, 75 μm or more is 3.0% by mass or less, and 20 μm or less is 5 to 12% by mass. The metal powder having a particle size of 75 μm or more has a weak combustion reaction, and the combustion continuity is lowered when the blending amount is increased. Even when the metal powder of 20 μm or less is less than 3% by mass, the combustion reaction becomes weak and the combustion continuity is lowered, which is not preferable. When the metal powder of 20 μm or less exceeds 14% by mass, the powder fluidity is lowered, causing pulsation and increasing the risk of backfire, which is not preferable.

(Ignition accelerator)
In the furnace bottom repair material according to the present invention, a metal powder ignition accelerator having a function of assisting the initial amount of heat necessary for the oxidation reaction of the metal silicon powder can be blended as necessary. By blending the ignition accelerator, it is possible to promote ignition at the start of thermal spraying even when the temperature of the workpiece is a relatively low temperature of 800 ° C. or less.

  As such a metal powder, for example, iron powder, manganese powder, vanadium powder, magnesium powder, titanium powder, or a powder of these alloys can be preferably used. These metal powders may be used alone or in combination of two or more. The ignition accelerator can be used if its ignition point is 300 to 800 ° C, but iron powder having an ignition point of 400 ° C or less can be most preferably used.

  When the ignition accelerator is added, the amount added is preferably 0.1 or more and 1.5% by mass or less based on the total amount of the main raw material. When the addition amount is less than 0.1% by mass, the effect of adding the ignition accelerator (ignition promotion effect) cannot be obtained sufficiently. On the other hand, when the addition amount is more than 1.5% by mass, there is an increase in the risk of work such as explosion or flashback, which is not preferable. Moreover, it is preferable that the particle diameter of a metal powder as an ignition accelerator is 100 micrometers or less. This is because if the particle size is larger than 100 μm, the reactivity becomes poor, and the effect of promoting ignition cannot be obtained.

(Combustion aid)
In the furnace bottom repair material according to the present invention, if necessary, a combustion auxiliary agent having a function of supplying oxygen during combustion of the furnace bottom repair material and oxidizing the metal silicon powder as the combustion agent on the workpiece is required. Can be blended. When the combustion auxiliary agent is attached to the metal silicon, the combustion auxiliary agent is made of a metal oxide powder that becomes an oxygen supply source by receiving heat when attached to the workpiece.

  Examples of such metal oxides include transition metal oxides, particularly first transition metal oxides (scandium oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, oxidation Copper) can be preferably used. When these metal oxides adhere to the metal silicon, the metal silicon is oxidized by lowering the oxidation number of the metal oxide during combustion on the workpiece. Since the metal silicon powder that is the combustion agent is oxidized, the combustion on the workpiece is continued. These metal oxides may be added alone or in combination of two or more. From the viewpoint of efficiently oxidizing metal silicon powder, iron oxide (Fe2O3) is particularly suitable because it has an effect of increasing the oxygen permeation rate when it is dissolved in SiO2 glass produced by oxidation of metal silicon powder. it can.

  When the combustion auxiliary agent is added, the amount added is not less than 0.3 and not more than 2.0% by mass with respect to the total amount of the main raw material. When the addition amount is less than 0.3% by mass, the combustion continuation effect of the combustor is reduced. On the other hand, when the addition amount is more than 2.0% by mass, impurities are increased and the composition changes so much that design characteristics such as thermal expansion characteristics cannot be exhibited. Moreover, it is preferable that the particle diameter of metal oxide powder is 100 micrometers or less. When the particle size is larger than 100 μm, the reactivity becomes poor and the effect of improving the continuity of combustion cannot be obtained.

(Other additives)
In addition to the components described above, fumed silica, oxides of elements selected from magnesium and iron, carbides, nitrides, and the like can be added for the purpose of improving fluidity and adjusting the mineral composition.

  The furnace bottom repair material of the present invention will be described below by presenting examples and comparative examples.

  Furnace bottom repair materials were prepared at the blending ratios shown in Tables 1 and 2, and construction bodies formed by thermal spraying using the respective furnace bottom repair materials were evaluated. The SiO2 refractory powder used in each furnace bottom repair material is silica brick powder. The Si purity of the metal silicon powder used in each furnace bottom repair is 97%. The purity of the quicklime powder used in each furnace bottom repair material is 96%. Tables 1 and 2 show the particle diameters of the SiO2 refractory powder and the particle diameters of the quicklime powder and the metal silicon powder.

  As the workability of furnace bottom repair, in order to evaluate ignitability, combustion continuity and adhesion rate, and to measure unevenness as construction physical properties and evaluate smoothness, 1 kg of each furnace bottom repair material is placed in the furnace. A construction body A was created by spraying a 230 × 230 × 30 mm siliceous brick placed on the floor surface in a flat shape.

  In addition, in order to evaluate the adhesive strength with the workpiece as a construction body characteristic, each furnace bottom repair material 3.5 kg was placed on a floor in the furnace, and a 230 × 230 × 30 mm enclosure with a 170 × 170 × 30 mm enclosure. The construction body B was created by spraying on a siliceous brick, slowly cooled to room temperature, and then cut into a size of 100 × 100 mm and used.

  In each construction, an ejector-type thermal spraying apparatus was used, the carrier gas was oxygen having a purity of 100%, and the flow rate was 29 Nm 3 / h. The material supply rate was 90 to 95 kg / h. When the lance is 2 m in diameter, the tip nozzle diameter is 21 mm, the atmospheric temperature in the furnace is heated to about 1000 ° C, the furnace is opened, and the brick surface temperature is cooled to about 800 ° C. went.

  The result of each evaluation regarding the construction body by each furnace bottom repair is described in Tables 1 and 2.

  The ignitability was evaluated by visually observing the time until ignition at the start of thermal spraying and the combustion state. “◎” indicates that the material started to ignite after less than 3 seconds, “◯” indicates that the material began to ignite after 3 seconds or more and less than 6 seconds, and “△” represents 6 seconds or more. It ignites in less than 10 seconds, indicating that material has begun to deposit.

  Combustion continuity was evaluated by visually observing the state of misfire during thermal spraying. “◎” indicates that even if the lance scanning speed is increased, there is no sign of misfire and combustion continues with strong light during combustion, and “○” indicates that there is no sign of misfire and combustion with strong light during combustion is performed. The lance scanning speed was increased to indicate that it was likely to misfire. “△” indicates that the lance scanning speed had to be reduced slightly to continue combustion. “●” indicates that the lance scanning speed was reduced. There was no sign of misfire even as early as possible, but there is a concern that the reaction will start at the tip of the nozzle because the light at the time of combustion is very strong and the tip of the nozzle is overheated due to an increase in the amount of heat generated by combustion. It shows that.

  The smoothness was evaluated by measuring the difference between the most concave portion and the most convex portion by 3D analysis in the central portion 30 mm × 30 mm range of the construction surface of the construction body A. “◎” indicates that the unevenness is less than 1.0 mm, “◯” indicates that the unevenness is 1.0 mm or more and less than 1.5 mm, and “Δ” indicates that the unevenness is 1.5 mm or more. "X" indicates that the unevenness was met at 2.0 mm or more and less than 4.0 mm, and "XX" indicates that the unevenness was met at 4.0 mm or more and less than 6.0 mm. Show.

  The adhesion rate calculated the ratio of the said adhesion mass with respect to the weight of the to-be-processed body before and after construction of the construction A after a thermal spray test, and the weight of the furnace bottom repair discharged from the tip nozzle.

  The adhesive strength was calculated by applying a shearing stress to the construction body portion of the sample cut out from the construction body B on the construction surface and peeling it, and dividing the load observed at the time of peeling by the adhesion area.

  In each example shown in Table 1, the content of the metal silicon powder is 10 to 20% by mass in the main raw material 100% by mass composed of the refractory powder made of silica brick powder, the metal silicon powder and the quick lime powder, Is a compounding content of 22 to 40% by mass.

  Further, iron powder having a particle size of 100 μm or less, which is an ignition accelerator, and ferric oxide (iron (III) oxide) powder having a particle size of 100 μm or less, which is a combustion auxiliary agent, are appropriately added. In addition, the addition amount of iron powder and ferric oxide powder is prescribed | regulated by the outer coating with respect to the main raw material whole quantity. Hereinafter, each formulation will be briefly described.

  In Examples 1 to 3 and Examples 7 to 8, the compounding amount of the quicklime powder is changed. Example 4 to Example 6 and Example 9 to Example 11 are the compounding of Example 3, with the particle size of quicklime powder, the compounding amount of ferric oxide powder, the compounding amount of iron powder, and the particle size compounding of silica stone brick powder. , Has been changed respectively. In Examples 12 to 13, the mixing ratio of the silica brick powder and the metal silicon powder in the combination of Example 3 is changed.

  As shown in Table 1, it can be understood that good results are obtained in each of the evaluation items of ignitability, combustion continuity, smoothness, adhesion rate, and adhesive strength.

  Next, comparative examples shown in Table 2 will be described. Comparative Example 1 is a blend that does not contain quicklime powder in comparison with the blends of Examples 1 to 3 and Examples 7 to 8 (zero blending amount). With this formulation, melting became insufficient and smoothness was reduced.

  In Comparative Examples 2 to 3, the amount of quicklime powder is changed in comparison with Example 3. The comparative example 2 is a case where the compounding quantity of quick lime is less than an appropriate quantity, and it became lack of melting and smoothness fell. Moreover, the comparative example 3 is a case where there is more than an appropriate quantity, and it became the lack of melting and smoothness fell.

  Comparative Example 4 to Comparative Example 6 are different from Example 3 in that the particle size of the quicklime powder is changed. The comparative example 4 is a case where the particle size of quicklime is biased to a coarser particle size distribution than appropriate, and the smoothness was lowered due to insufficient melting. Further, Comparative Examples 5 to 6 were cases where the particle size distribution was biased to a finer particle size than appropriate, and the combustion continuity was significantly lowered and the adhesion rate was also lowered.

  As described above, the furnace bottom repair material is composed of SiO2 refractory powder, metal powder as a combustion agent, and quicklime powder, and by making the quicklime powder particle size and content appropriate, smooth and adhesive strength It is possible to have sufficient combustion continuity while forming a high construction body. Thereby, since the unevenness | corrugation of a furnace bottom damaged part can be repaired smoothly, horizontally and firmly, without damaging a to-be-processed surface, workability | operativity and construction quality improve. As a result, an unnecessarily long working time can be suppressed, the risk of clogging is reduced, and the repair frequency is also reduced, so that an increase in construction cost can be prevented. Further, the time for the construction worker to be exposed to a high temperature and dusty environment is not unnecessarily long.

  As described above, the furnace bottom repair material according to the present invention can be applied smoothly and horizontally, and is excellent in adhesive strength. Therefore, it is useful as a repair member used for furnace bottom repair in a coke oven carbonization chamber.

Claims (5)

A furnace bottom repair material used for a thermal spraying method that repairs a repaired surface by spraying with oxygen, including a main raw material composed of a refractory powder of SiO2 and a metal powder as a combustion agent and quicklime powder,
5 mass% or less of particles larger than 355 μm with respect to the total amount of the main raw material, 7 to 20 mass% of particles of 75 μm or less, and 22 to 40 mass% of quick lime powder that is 75 to 355 μm of the balance. Furnace bottom repair material. 40 to 68 mass% of the refractory powder with respect to the total amount of the main raw material,
The furnace bottom repair material of Claim 1 which contains 10-20 mass% of metal silicon powder as said metal powder with respect to the whole quantity of the said main raw material.   As an ignition accelerator, at least one selected from iron powder, manganese powder, vanadium powder, magnesium powder, titanium powder, or a powder of an alloy thereof is used as an external coating of the main raw material in an amount of 0. The furnace bottom repair material according to claim 1 or 2, further added in an amount of 1 to 1.5 mass%.   The transition metal oxide is further added as a combustion auxiliary agent in an amount of 0.3 to 2.0% by mass based on the total amount of the main raw material, according to any one of claims 1 to 3. Furnace bottom repair material.   The combustion aid is scandium oxide, titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, lithium peroxide, calcium peroxide, magnesium peroxide, strontium peroxide, peroxide The furnace bottom repair material according to any one of claims 1 to 4, which is at least one selected from barium.