Monomorphic refractory composition, monomorphic refractory material, and method for manufacturing monomorphic refractory material

Abstract

To provide a castable refractory composition with excellent adaptability to a rapidly rising temperature, while maintaining excellent thermal conductivity, a castable refractory formed of the castable refractory composition, and a method of producing the same.SOLUTION: The castable refractory composition includes silicon carbide, aluminum lactate, and organic fibers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a monolithic refractory composition, a monolithic refractory, and a method for manufacturing a monolithic refractory.

Background Art

[0002] In recent years, monolithic refractory compositions have been widely used in various fields because of their improved workability and ease of repair.

[0003] Monolithic refractory compositions generally contain alumina cement as a binder. However, when a monolithic refractory composition contains alumina cement, the heat resistance of the monolithic refractory produced from the monolithic refractory composition tends to decrease. Therefore, attempts have been made to reduce the content of alumina cement. For example, in Patent Document 1, a monolithic refractory composition in which the content of alumina cement is reduced and refractory powder is added to the aggregate has been proposed.

[0004] Depending on drying conditions such as the heating rate and drying temperature, the monolithic refractory composition after construction may crack in the monolithic refractory, and as a result of the rapid increase in the water vapor pressure in the refractory, there is a risk of a bursting phenomenon. Therefore, it is necessary to set the drying conditions strictly. In Patent Document 2, in order to prevent the occurrence of the above cracks and bursting phenomenon, a monolithic refractory composition is made to contain basic aluminum organic acid and polyvinyl alcohol. Also, in Patent Document 3, a castable refractory containing an aggregate, basic aluminum lactate, and alumina cement has been proposed. Also, in Patent Document 4, a castable monolithic refractory containing an aggregate, basic aluminum lactate, polyvinyl alcohol short fibers, and alumina cement has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the furnaces of boilers and other similar equipment (e.g., stoker incinerators with power generation boilers), monolithic refractories require high thermal conductivity from the standpoint of efficient heat recovery. Silicon carbide is known as a material that improves the thermal conductivity of monolithic refractories, but using such a highly thermally conductive material makes it prone to explosion, thus requiring more strict control of drying conditions.

[0007] On the other hand, in order to shorten construction periods, there is a need for monolithic refractory compositions that do not cause the above problems even at high heating rates and have high suitability for rapid heating. However, currently, no monolithic refractory compositions with excellent thermal conductivity and suitability for rapid heating are known, and their development is needed.

[0008] In view of the above circumstances, the object of this disclosure is to provide an amorphous refractory composition that maintains excellent thermal conductivity while exhibiting excellent suitability for rapid temperature rise, an amorphous refractory material formed from the amorphous refractory composition, and a method for manufacturing the same. [Means for solving the problem]

[0009] The specific means to achieve the above objectives are as follows:

[0010] <1> An amorphous refractory composition comprising silicon carbide, aluminum lactate, and organic fibers. <2> As aggregate, containing silicon carbide, <1> The amorphous fire-resistant composition described above. <3> As a fire-resistant powder, it contains silicon carbide. <1> or <2> The amorphous fire-resistant composition described above. <4> Organic fibers include polypropylene fibers. <1> ~ <3> An amorphous fire-resistant composition as described in any one of the following. <5> Further containing bentonite, <1> ~ <4> An amorphous fire-resistant composition as described in any one of the following. <6> Aluminum lactate comprises at least one selected from the group consisting of basic aluminum lactate and hydrated basic aluminum lactate. <1> ~ <5> An amorphous fire-resistant composition as described in any one of the following. <7> The fiber length of the organic fiber is 10 μm to 20 mm. <1> ~ <6> An amorphous fire-resistant composition as described in any one of the following. <8> The aluminum lactate content in the amorphous refractory composition is 0.1% to 0.9% by mass. <1> ~ <7> An amorphous fire-resistant composition as described in any one of the following. <9> The organic fiber content in the amorphous refractory composition is 0.005% by mass to 0.5% by mass. <1> ~ <8> An amorphous fire-resistant composition as described in any one of the following. <10> The silicon carbide content in the amorphous refractory composition is 70% to 95% by mass. <1> ~ <9> An amorphous fire-resistant composition as described in any one of the following. <11> Used in spray application, <1> ~ <10> An amorphous fire-resistant composition as described in any one of the following. <12> <1> ~ <11> A monolithic refractory material formed by a monolithic refractory composition described in any one of the following. <13> <1> ~ <11> A method for producing an unshaped refractory material, comprising spraying an unshaped refractory composition described in any one of the above onto a workpiece and drying it. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide an amorphous refractory composition that maintains excellent thermal conductivity while exhibiting excellent suitability for rapid temperature rise, an amorphous refractory material formed from the amorphous refractory composition, and a method for manufacturing the same. [Brief explanation of the drawing]

[0012] [Figure 1] FIG. 1 is a diagram for explaining a method for manufacturing an amorphous refractory using an air flow conveyance spraying construction method.

Embodiments for Carrying out the Invention

[0013] Hereinafter, embodiments for implementing the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to numerical values and their ranges, which do not limit the present disclosure.

[0014] In the numerical range indicated by "~" in the present disclosure, the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerically described range. Also, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the synthesis example. In the present disclosure, each component may contain a plurality of corresponding compounds. When there are a plurality of substances corresponding to each component in the composition, the content rate of each component means the total content rate of the plurality of substances present in the composition, unless otherwise specified.

[0015] (Amorphous refractory composition) The amorphous refractory composition of the present disclosure contains silicon carbide, aluminum lactate, and organic fibers.

[0016] According to the amorphous refractory composition of the present disclosure, an amorphous refractory composition excellent in rapid temperature rise suitability can be provided while maintaining excellent thermal conductivity.

[0017] The reason for the above effect is presumed as follows, but is not limited thereto. The amorphous refractory composition disclosed herein contains silicon carbide, which has high thermal conductivity. While silicon carbide in amorphous refractory compositions generally has a dense structure, the amorphous refractory composition disclosed herein contains both aluminum lactate and organic fibers, and when volume shrinkage occurs due to gelation caused by the addition of construction water, continuous pores are formed. Since internal water vapor can be released to the outside through these pores, it is presumed that the occurrence of cracks and spalling phenomena can be prevented even at high heating rates, thereby improving suitability for rapid heating.

[0018] The following describes each component included in the amorphous fire-resistant composition of this disclosure.

[0019] (Silicon carbide) The amorphous refractory composition disclosed herein contains silicon carbide. The amorphous refractory composition disclosed herein may contain silicon carbide as aggregate, may contain silicon carbide as refractory powder, or may contain silicon carbide as both aggregate and refractory powder. In this disclosure, "containing silicon carbide as aggregate" means containing silicon carbide with an average particle size of 30 μm or more and 10 mm or less. Furthermore, in this disclosure, "containing silicon carbide as a refractory powder" means containing silicon carbide particles with an average particle size of 1 μm or more and less than 30 μm. Furthermore, in this disclosure, "containing silicon carbide as aggregate and refractory powder" means containing silicon carbide with an average particle size of 30 μm or more and 10 mm or less, and silicon carbide with an average particle size of 1 μm or more and less than 30 μm. The average particle size of silicon carbide can be measured by a sieving test in accordance with JIS Z 8815:1994. Furthermore, the average particle size of silicon carbide particles smaller than 100 μm can be measured using the laser diffraction particle size distribution method in accordance with JIS Z 8825:2013, and this is the particle size at which the cumulative average diameter is 50%.

[0020] Furthermore, from the viewpoint of transportability, the average particle size of silicon carbide relative to the inner diameter of the transport pipe is preferably 1 / 10 to 1 / 2, and more preferably 1 / 7 to 1 / 3. The proportion of silicon carbide that satisfies the above relationship, relative to the total amount of silicon carbide in the amorphous refractory composition (100% by mass), is preferably 90% by mass or more, and more preferably 95% by mass or more.

[0021] When an amorphous refractory composition contains silicon carbide with an average particle size of 30 μm or more and 10 mm or less (hereinafter also referred to as specific silicon carbide A), from the viewpoint of improving physical properties through close packing, the content of specific silicon carbide A relative to 100% by mass of the total amount of silicon carbide contained in the amorphous refractory composition is preferably 60% to 98% by mass, more preferably 70% to 97% by mass, and even more preferably 85% to 95% by mass.

[0022] When an amorphous refractory composition contains silicon carbide with an average particle size of 1 μm or more and less than 30 μm (hereinafter also referred to as specific silicon carbide B), from the viewpoint of improving physical properties through close packing, the content of specific silicon carbide B relative to 100% by mass of the total amount of silicon carbide contained in the amorphous refractory composition is preferably 2% to 40% by mass, more preferably 3% to 30% by mass, and even more preferably 5% to 15% by mass.

[0023] From the viewpoint of thermal conductivity, the silicon carbide content in the amorphous refractory composition is preferably 60% to 95% by mass, more preferably 70% to 95% by mass, and even more preferably 80% to 95% by mass.

[0024] (aluminum lactate) Examples of aluminum lactate include aluminum lactate normal salt represented by Al(OCOCH(OH)CH3)3, basic aluminum lactate represented by Al(OH)(OCOCH(OH)CH3)2 or Al(OH)2(OCOCH(OH)CH3), and hydrates thereof. Among those described above, it is preferable that aluminum lactate includes at least one selected from the group consisting of basic aluminum lactate and hydrated basic aluminum lactate. Furthermore, as aluminum lactate, a composite salt with citric acid or glycolic acid may be used.

[0025] The aluminum lactate content in the amorphous refractory composition is preferably 0.1% to 0.9% by mass, more preferably 0.2% to 0.8% by mass, and even more preferably 0.3% to 0.7% by mass. By increasing the aluminum lactate content to 0.1% by mass or more, the suitability for rapid temperature rise can be further improved. By limiting the aluminum lactate content to 0.9% by mass or less, the occurrence of curing shrinkage cracks in monolithic refractories manufactured using the monolithic refractory composition of the present disclosure can be suppressed.

[0026] (Organic fibers) The type of organic fiber is not particularly limited and includes, for example, polypropylene fibers, polyethylene fibers, polyester fibers, polyvinyl alcohol fibers, and cellulose fibers. Among these, from the viewpoint of suitability for rapid temperature rise, it is preferable that the organic fiber includes polypropylene fibers. The amorphous fire-resistant composition disclosed herein may contain two types of organic fibers.

[0027] The fiber length of the organic fiber is preferably 10 μm to 20 mm, more preferably 100 μm to 15 mm, and particularly preferably 1.0 mm to 10 mm. By using organic fibers with a fiber length of 10 μm or more, the suitability for rapid temperature increase can be further improved. By limiting the fiber length of the organic fibers to 20 mm or less, the conveyance performance by air-flow type sprayers can be improved. The amorphous fire-resistant composition of this disclosure may contain two or more organic fibers with different fiber lengths. In this disclosure, the fiber length is measured in accordance with JIS L 1015:2010.

[0028] The fineness of the organic fiber is preferably 0.1 dtex to 20 dtex, and more preferably 0.5 dtex to 15 dtex. By using organic fibers with a fineness of 0.1 dtex or higher, the suitability for rapid temperature increase can be further improved. By using organic fibers with a fineness of 20 dtex or less, the conveyance performance by airflow-type spraying machines can be improved. In this disclosure, the fineness is measured in accordance with JIS L 1015:2010.

[0029] The organic fiber content in the amorphous refractory composition of this disclosure is preferably 0.005% to 0.7% by mass, more preferably 0.01% to 0.5% by mass, even more preferably 0.05% to 0.4% by mass, and particularly preferably 0.1% to 0.3% by mass. By increasing the organic fiber content to 0.005% by mass or more, the suitability for rapid temperature rise can be further improved. By limiting the organic fiber content to 0.7% by mass or less, the transportability by airflow-type spraying machines can be improved.

[0030] (Bentonite) The amorphous refractory compositions disclosed herein may contain bentonite. Bentonite is a weakly alkaline clay rock whose main component is the clay mineral montmorillonite. Furthermore, bentonite may contain silica minerals such as quartz, α-cristobalite, and opal as minor components. Furthermore, bentonite may be associated with silicate minerals such as feldspar, mica, and zeolite, carbonate minerals such as calcite, dolomite, and gypsum, sulfate minerals, and sulfide minerals such as pyrite.

[0031] From the viewpoint of rapid setting action, the average particle size of bentonite is preferably 45 μm or less, and more preferably 10 μm or less. Furthermore, the average particle size of the bentonite may be, for example, 1 μm or more. In this disclosure, the average particle size of bentonite can be measured by a laser diffraction particle size distribution method in accordance with JIS Z 8825:2013, and is the particle size at which the cumulative average diameter is 50%.

[0032] The bentonite content in the amorphous refractory composition of this disclosure is preferably 0.5% to 5% by mass, and more preferably 1% to 3% by mass. By increasing the bentonite content to 0.5% by mass or more, dust generation during spraying can be reduced. By limiting the bentonite content to 5% by mass or less, the strength, corrosion resistance, and transportability by air-flow spraying machines of refractories manufactured using monolithic refractory compositions can be improved.

[0033] (Refractory powders other than silicon carbide) As described above, the amorphous refractory composition of this disclosure may contain silicon carbide as a refractory powder, but may also contain one or more refractory powders other than silicon carbide. Other refractory powders besides silicon carbide are not particularly limited in type, as long as they can penetrate the gaps between aggregates and bind them together. Examples of other refractory powders include alumina, titania, bauxite, diaspore, mullite, van shale, chamotte, pyrophyllite, sillimanite, andalusite, silica, chromite, spinel, magnesia, zirconia, zircon, chromia, silicon nitride, aluminum nitride, boron carbide, titanium boride, zirconium boride, and silica. The materials described above may be used in a colloidal state, either entirely or partially, dispersed in a liquid.

[0034] The average particle size of the refractory powder other than silicon carbide is preferably 0.1 μm or more and less than 30 μm, and more preferably 0.5 μm or more and less than 5 μm. In this disclosure, the average particle size of the refractory powder can be measured by a laser diffraction particle size distribution method in accordance with JIS Z 8825:2013, and the particle size is defined as the particle size at which the cumulative average diameter is 50%.

[0035] The content of refractory powders other than silicon carbide in the amorphous refractory composition of this disclosure is preferably 1% to 24% by mass, and more preferably 3% to 20% by mass. By increasing the content of refractory powders other than silicon carbide to 1% by mass or more, the strength and corrosion resistance of refractories manufactured using amorphous refractory compositions can be improved. By limiting the content of refractory powders other than silicon carbide to 24% by mass or less, dust generation during spraying can be reduced, and the conveyance performance by air-flow type spraying machines can be improved.

[0036] (Aggregates other than silicon carbide) As described above, the amorphous refractory composition may contain silicon carbide as aggregate, but may also contain one or more types of aggregate other than silicon carbide. Examples of aggregates other than silicon carbide include alumina, bauxite, diaspore, mullite, kyanite, bann shale, chamotte, silica, pyrophyllite, sillimanite, andalusite, chromite, spinel, magnesia, zirconia, zircon, chromia, silicon nitride, aluminum nitride, boron carbide, graphite, titanium boride, and zirconium boride.

[0037] The preferred average particle size of aggregates other than silicon carbide is preferably 30 μm or more and 10 mm or less. The amorphous refractory composition of this disclosure may contain two or more aggregates with different average particle sizes.

[0038] From the viewpoint of thermal conductivity, the content of aggregates other than silicon carbide in the amorphous refractory composition is preferably 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 5% by mass or less.

[0039] (Binder) The amorphous fire-resistant compositions disclosed herein may contain one or more binders. The type of binder is not particularly limited and includes, for example, alumina cement, high alumina cement, activated magnesia, combinations of low-reactivity alkaline earth metal oxides and water-soluble organic or inorganic salts, phosphates such as phosphoric acid and aluminum phosphate, silicates such as sodium silicate and potassium silicate, lignin sulfonates, and water-soluble phenols. Among the above, alumina cement is preferred because it can maintain the strength of refractories manufactured using amorphous refractory compositions over a wide temperature range from room temperature to high temperatures.

[0040] From the viewpoint of compressive strength during curing, the average particle size of the binder is preferably less than 40 μm, more preferably less than 20 μm, and even more preferably less than 15 μm. Furthermore, the average particle size of the binder may be, for example, 1 μm or larger. In this disclosure, the average particle size of the binder can be measured by a laser diffraction particle size distribution method in accordance with JIS Z 8825:2013, and the particle size is the one in which the cumulative average diameter is 50%.

[0041] The binder content in the amorphous refractory composition of this disclosure is preferably 1% to 15% by mass, and more preferably 3% to 12% by mass. By increasing the binder content to 1% by mass or more, the strength and corrosion resistance of monolithic refractories manufactured using monolithic refractory compositions can be improved. Furthermore, the curing time can be shortened, further reducing the construction period. By limiting the binder content to 15% by mass or less, the curing time of the monolithic refractory composition can be adjusted to be suitable for the formation of monolithic refractories. Furthermore, if the monolithic refractory composition of this disclosure contains alumina cement, from the viewpoint of the curing time of the monolithic refractory composition and the heat resistance of the monolithic refractory product produced by the monolithic refractory composition, the alumina cement content in the monolithic refractory composition is preferably 1% to 10% by mass, and more preferably 3% to 9% by mass.

[0042] (Dispersant) The amorphous fire-resistant compositions disclosed herein may contain one or more dispersants. The type of dispersant is not particularly limited and examples include phosphate-based dispersants, carboxylic acid-based dispersants, and sulfonic acid-based dispersants. Examples of phosphate-based dispersants include condensed phosphates such as sodium tripolyphosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate. Examples of carboxylic acid-based dispersants include polycarboxylates and polyacrylates. Examples of sulfonic acid-based dispersants include melamine sulfonate and β-naphthalene sulfonate.

[0043] The dispersant content in the amorphous refractory composition of this disclosure is preferably 0.05% to 0.5% by mass, and more preferably 0.07% to 0.3% by mass. By increasing the dispersant content to 0.05% by mass or more, the strength and corrosion resistance of refractories manufactured using monolithic refractory compositions can be improved. By reducing the dispersant content to 0.5% by mass or less, long-term curing performance can be improved.

[0044] The amorphous refractory composition disclosed herein can be produced by kneading the above components by a conventionally known method. For mixing, an omni mixer, paddle mixer, Nauta mixer, Eilich mixer, vortex mixer, or continuous mixing device can be used.

[0045] (Uses of amorphous fire-resistant materials) The monolithic refractory composition disclosed herein can be used in the manufacture of monolithic refractory materials. Monomorphic refractories may be manufactured by spraying, pouring, or casting, but the monomorphic refractory composition disclosed herein is more suitable for manufacturing monomorphic refractories by spraying. Furthermore, from the viewpoint of shortening the construction period, spraying is preferable. The spray application can be either dry or wet, but from the viewpoint of the strength of the monolithic refractory material, wet spray application is preferred.

[0046] (Unshaped refractories) The monolithic refractories disclosed herein are formed from the monolithic refractory composition described above.

[0047] (Method of manufacturing unshaped refractories) The method for manufacturing an amorphous refractory material according to the present disclosure includes spraying the amorphous refractory composition onto an object to be constructed and drying it. Furthermore, the method for producing the monolithic fire-resistant composition of this disclosure may include adding application water to the monolithic fire-resistant composition before spraying it onto the object to be treated.

[0048] Hereinafter, an example of a method for manufacturing monolithic refractories using the monolithic refractory composition of this disclosure will be described with reference to Figure 1.

[0049] First, let's explain the airflow-conveying spray application device 1 shown in Figure 1. As shown in Figure 1, this spray application apparatus 1 comprises an airflow conveyor 2, a conveying pipe 3, a construction water addition means 4, a construction water addition unit 5, a spray nozzle 6, and a compressor 7.

[0050] The airflow conveyor 2 uses compressed air from the compressor 7 to convey the powdered monolithic refractory composition 21 into the conveying pipe 3 at a predetermined solid / gas ratio. The conveyed monolithic refractory composition 21 is then further conveyed from one end of the conveying pipe 3 (the airflow conveyor 2 side) to the other end (the spray nozzle 6 side).

[0051] The compressor 7 supplies compressed air to the airflow conveyor 2. The amorphous refractory composition 21 is transported in the airflow conveyor 2 by compressed air supplied from the compressor 7 through the conveying pipe 3. The airflow conveyor 2 is not particularly limited as long as it can convey the powdered amorphous refractory composition 21 through the conveying pipe 3 using compressed air. For example, a spraying machine such as the Need Gun (product name) manufactured by AGC Plibrico Co., Ltd. can be used.

[0052] The amount of powdered monolithic refractory composition 21 conveyed per unit time can be adjusted by continuously supplying a predetermined amount of the powdered monolithic refractory composition 21 to the airflow conveyor 2 and using compressed air supplied from the compressor 7 to send it to the conveying pipe 3.

[0053] The amorphous refractory composition 21, which has been fed into the conveying pipe 3, is transported within the conveying pipe 3 towards the spray nozzle 6 by compressed air supplied to the airflow conveyor 2. The length of the transport pipe 3 is not particularly limited, but can be, for example, 10m to 200m.

[0054] The transport pipe 3 is a passage for transporting the powdered amorphous refractory composition 21 to the spray nozzle using compressed air. Furthermore, even if construction water is added to the monolithic refractory composition 21 during transport, causing the monolithic refractory composition 21 to become wet, the monolithic refractory composition is still transported to the spray nozzle 6 by compressed air. In other words, the conveying pipe 3 only needs to be capable of stably conveying the powdered monolithic refractory composition 21 and the wet monolithic refractory composition 21 by connecting the airflow conveyor 2 and the spray nozzle 6.

[0055] The transport pipe 3 is not particularly limited and may include, for example, a transport pipe made of metal such as steel, a transport pipe made of rubber, or a transport pipe made of resin such as polyethylene. Rubber and resin transport pipes are preferable because they can be positioned according to the site conditions and are easy to move. Furthermore, they are preferable because they allow for stable construction even when the construction site is at a high elevation.

[0056] The inner diameter of the transport pipe 3 is preferably changed as appropriate depending on the amount and size of the amorphous fire-resistant composition 21 to be transported, as well as the site environment in which the construction is carried out. For example, from the viewpoint of the amount sprayed per unit time, the inner diameter of the transport pipe 3 is preferably 65 mm or less. Furthermore, from the standpoint of preventing pressure loss, the inner diameter of the transport pipe 3 is preferably 25 mm or larger.

[0057] In the amorphous refractory composition 21, the contained components may form clumps due to aggregation or other means. From the viewpoint of ease of transport, the ratio of the maximum particle diameter of the aggregate contained in the amorphous refractory composition 21 to the inner diameter of the transport pipe 3 (maximum particle diameter of the aggregate / inner diameter of the transport pipe) is preferably 1 / 10 to 1 / 2, and more preferably 1 / 7 to 1 / 3. Typically, the above conditions are met if the inner diameter of the conveying pipe is between 38mm and 65mm. In this disclosure, the maximum particle diameter of the above-mentioned clump can be measured by a sieving test in accordance with JIS Z 8815:1994.

[0058] The length of the transport pipe 3 is not limited as long as it can stably transport the amorphous refractory composition 21.

[0059] The construction water addition means 4 involves adding construction water into the transport pipe 3 in which the powdered amorphous refractory composition 21 is being transported, thereby wetting the amorphous refractory composition 21. The wet, amorphous refractory composition 21 is transported to the spray nozzle 6 by compressed air from the airflow conveyor 2. The construction water is added to the amorphous refractory composition 21 in the construction water addition section 5 of the transport pipe 3 by the construction water addition means 4.

[0060] The construction water addition means 4 is preferably a metal pipe made of stainless steel or the like, a rubber hose, or a resin hose made of polyethylene or the like. The inner diameter of the construction water addition means 4 can be appropriately selected depending on the amount of construction water to be added and the environment of the construction site, and is generally preferably 9 mm to 25 mm. The length of the construction water adding means 4 is preferably changed as appropriate depending on the location of the construction water supply source. However, since the construction water supply source is usually located near the airflow conveyor 2, the construction water adding means 4 is typically about the same length as the conveyor pipe 3.

[0061] The construction water addition means 4 is connected to a water addition port (not shown) of the construction water addition section 5, which is provided in the middle of the transport pipe 3, so that construction water can be supplied into the transport pipe 3. From the viewpoint of the mixability of the amorphous fire-resistant composition 21 and the application water, and from the viewpoint of preventing the accumulation of the amorphous fire-resistant composition 21 and blockage of the transport pipe 3, the placement of the application water addition section 5 is preferably 0.3 m to 1 m upstream from the tip of the spray nozzle 6.

[0062] From the viewpoint of spraying characteristics and the physical properties of the constructed object, the amount of construction water added per 100 parts by mass of the total amount of amorphous fire-resistant composition 21 is preferably 5 to 15 parts by mass, and more preferably 7 to 13 parts by mass.

[0063] In studies on the structure of dispersion systems of powder, water, and air, it is generally observed that these three systems can take on various structures. However, in the conveying pipe, the wet monolithic refractory composition 21 is thought to form a so-called "fiber (II) region" (Umeya: JSPS 136 Committee, Monolithic Refractory Construction Technology Council Research Meeting materials), in which air is trapped within continuous particles of powder and water. The wet monolithic refractory composition 21 is then transported while floating within the conveying pipe. However, this is a presumption of the mechanism and does not restrict the interpretation of this disclosure.

[0064] The spray nozzle 6 is attached to the tip of the transport pipe 3 and sprays the amorphous fire-resistant composition 21, to which construction water has been added, onto the object to be treated 22. The spray nozzle 6 is not particularly limited, and conventionally known nozzles can be used. The compressed air used for transport is released into the outside air by the impact when it is sprayed onto the object to be constructed 22. After degassing, the sprayed amorphous refractory composition 21 rapidly aggregates and then hardens to form an amorphous refractory material 23, creating a strong furnace wall. Formwork or the like may be used during construction as needed. [Examples]

[0065] The above embodiments will be described in detail below with reference to preparation examples, but the above embodiments are not limited to these examples. Examples 1 to 9 are examples, and Examples 10 to 11 are comparative examples. Furthermore, unless otherwise specified, the values ​​in the table refer to "parts of mass".

[0066] (Examples 1-11) An amorphous refractory composition was prepared by kneading various components according to the formulations shown in Table 1. Details of the various components shown in Table 1 are as follows. • Silicon carbide: A mixture of silicon carbide with an average particle size of 30 μm or more and 10 mm or less, and silicon carbide with an average particle size of 1 μm or more and less than 30 μm (each contained in a ratio of 75.15:5 by mass) • A mixture of alumina and silica (aggregate other than silicon carbide, with an average particle size of 30 μm to 10 mm) • Aluminum lactate: Basic aluminum lactate • Organic fiber A: Polypropylene fiber with a fiber length of 5 mm and a fineness of 2 dtex. • Organic fiber B: Polypropylene fiber with a fiber length of 0.5 mm and a fineness of 2 dtex. • Organic fiber C: Polypropylene fiber with a fiber length of 25 mm and a fineness of 2 dtex. • Organic fiber D: PVA fiber (vinylon) with a fiber length of 3 mm and a fineness of 2 dtex. • Bentonite: Average particle size less than 10 μm • Refractory powders other than silicon carbide: A mixture of alumina and silica fume with an average particle size of 0.5 μm or more and less than 5 μm. • Binder: Alumina cement, average particle size less than 15 μm • Dispersant: Sodium tripolyphosphate

[0067] <<Thermal Conductivity Evaluation>> 10,000 g of the amorphous refractory composition prepared in Examples 1 to 11 was dry-kneaded for 1 minute, then 800 g of water was added as needed and kneaded for 3 minutes to obtain a mixture. Two test specimens were prepared by pressing this mixture into a mold measuring 180 mm × 114 mm × 65 mm. The samples were cured at 20°C for 24 hours and then fired at 800°C for 3 hours. Thermal conductivity was measured according to JIS R 2251-1:2007. Evaluation was performed based on the following criteria. The evaluation results are shown in Table 1. (Evaluation Criteria) AA: The thermal conductivity was 7 W / (m·K) or higher. A: The thermal conductivity was between 5 W / (m·K) and less than 7 W / (m·K). B: The thermal conductivity was between 4 W / (m·K) and 5 W / (m·K), but this is not a practical problem.

[0068] <<Rapid Temperature Rise Suitability Evaluation>> 10,000 g of the amorphous refractory composition prepared in Examples 1 to 11 was dry-kneaded for 1 minute, then 800 g of water was added as needed and kneaded for 3 minutes to obtain a mixture. Two cylindrical test specimens were prepared by pressing this mixture into a mold measuring 100 mm in height and 100 mm in diameter. After curing in a 20°C environment for 24 hours, the sample was placed in an electric furnace with a 1000°C atmosphere. After 30 minutes, it was removed and visually inspected for any explosions. The suitability for rapid heating was then evaluated based on the evaluation criteria described below. The evaluation results are shown in Table 1. (Evaluation Criteria) A: No explosions were observed in the cylindrical test specimen. B: One explosion site was observed in the cylindrical test specimen. C: Two or more explosion sites were observed in the cylindrical test specimen, indicating a problem with its suitability for rapid heating.

[0069] <<Cured Appearance Evaluation>> The evaluation was conducted based on the following criteria. The evaluation results are shown in Table 1. (Evaluation Criteria) 10,000 g of the amorphous refractory composition prepared in Examples 1 to 11 was dry-kneaded for 1 minute, then 800 g of water was added as needed and kneaded for 3 minutes to obtain a mixture. One test specimen was prepared by pressing this mixture into a mold measuring 420 mm x 420 mm x 40 mm. After curing in a 20°C environment for 24 hours, the appearance of the test specimens was observed visually and evaluated according to the evaluation criteria below. The evaluation results are shown in Table 1. A: No curing shrinkage cracks were observed in the test specimens. B: Curing shrinkage cracks were observed in the test specimen.

[0070] [Table 1]

[0071] The amorphous refractory composition disclosed herein has been shown to exhibit excellent suitability for rapid temperature increases while maintaining excellent thermal conductivity. [Explanation of Symbols]

[0072] 1: Airflow-type spray application device, 2: Airflow conveyor, 3: Conveyor pipe, 4: Application water addition means, 5: Application water addition section, 6: Spray nozzle, 7: Compressor, 21: Monomorphic refractory composition, 22: Object to be applied, 23: Monomorphic refractory material

Claims

1. It contains silicon carbide, aluminum lactate, and organic fibers. The silicon carbide content in the amorphous refractory composition is 80% to 95% by mass. The aluminum lactate content in the amorphous refractory composition is 0.2% by mass to 0.9% by mass. The silicon carbide mentioned above includes silicon carbide as a refractory powder. The silicon carbide used as the refractory powder refers to silicon carbide with an average particle size of 1 μm or more and less than 30 μm. Amorphous refractory composition.

2. The silicon carbide comprises silicon carbide as aggregate, The amorphous refractory composition according to claim 1, wherein the silicon carbide used as aggregate means silicon carbide with an average particle size of 30 μm or more and 10 mm or less.

3. The amorphous fire-resistant composition according to claim 1 or claim 2, wherein the organic fiber includes polypropylene fiber.

4. An amorphous refractory composition according to any one of claims 1 to 3, further comprising bentonite.

5. The amorphous refractory composition according to any one of claims 1 to 4, wherein the aluminum lactate comprises at least one selected from the group consisting of basic aluminum lactate and hydrated basic aluminum lactate.

6. The amorphous fire-resistant composition according to any one of claims 1 to 5, wherein the content of the organic fibers in the amorphous fire-resistant composition is 0.005% by mass to 0.5% by mass.

7. An amorphous fire-resistant composition according to any one of claims 1 to 6, used for spray application.

8. A monomorphic refractory material formed by the monomorphic refractory composition described in any one of claims 1 to 7.

9. A method for producing an amorphous refractory material, comprising spraying an amorphous refractory composition according to any one of claims 1 to 7 onto a workpiece and drying it.

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