JP2011093726A - Molded refractory for metal casting, method for manufacturing molded refractory for metal casting, castable refractory composition, and holding member of molten metal for metal casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light molded refractory for metal casting having good insulation (thermal insulation) that can suppress sticking of metal caused by penetration of molten metal and surface reaction without need for postprocessing such as coating. <P>SOLUTION: The molded refractory for metal casting is made of a raw material including 9-95 mass% of inorganic fiber, 4-20 mass% of a silica binder, and 1-87 mass% of at least one ionic substance selected from calcium fluoride, magnesium fluoride, calcium oxide, magnesium oxide, barium oxide, and barium sulfate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refractory molded body for metal casting that can be suitably used in a portion that is in direct contact with a molten metal in a casting apparatus for aluminum, magnesium, etc., a method for producing a refractory molded body for metal casting, an amorphous refractory composition, and a metal casting. The present invention relates to a molten metal holding member.

  In a non-ferrous metal casting apparatus such as aluminum, a refractory molded body for metal casting is widely used as a lining material for constructing a molten metal holding member that comes into contact with a molten metal such as a firewood, a molten metal holding furnace, and a ladle. . At present, fire-resistant castables containing alumina cement and fired products thereof are mainly used as fire-resistant molded bodies for metal casting, and fire-resistant molded bodies for metal casting are also called fire bricks.

  The refractory molded body for metal casting that is used for the part that comes into direct contact with the molten metal is stuck to the surface due to the reaction with the molten metal and the penetration of the molten metal at the time of use. When it tried to peel, the fireproof molded object also peeled together and the technical subject of causing damage existed.

  As a means to solve the above technical problem, a refractory molded article that attempts to suppress the penetration of molten metal by adding a refractory raw material fine powder having a particle size of 1 μm or less to alumina cement to reduce the porosity and the pore diameter is reported. (See Patent Document 1 (Japanese Patent Publication No. 59-37431)).

  Patent Document 2 (Japanese Patent Laid-Open No. 2002-274959) discloses a refractory molded body for aluminum and aluminum alloys containing a refractory powder material such as chamotte, a binder such as ultrafine silica, and a fluorine compound. According to this refractory molded body for aluminum and aluminum alloy, penetration of molten aluminum is prevented, and adhesion of molten oxide or the like to the surface of the refractory molded body is sufficiently prevented.

Japanese Examined Patent Publication No.59-37431 JP 2002-274959 A (Claim 3)

  However, in a refractory molded body having a reduced porosity and pore diameter as described in Patent Document 1, it is difficult to prevent the metal melt from sticking. Moreover, the fireproof molded object for aluminum and aluminum alloy of patent document 2 is what suppresses the penetration | infiltration of a molten metal, and aims at preventing adhesion of a molten metal oxide to the surface of a fireproof molded object. However, its adhesion prevention effect is still not sufficient.

  Under such circumstances, there are various coating agents to be applied to the surface of the refractory molded body in order to suppress the reaction with the molten metal and the penetration of the molten metal, but the coating agent will peel off when used repeatedly. Therefore, regular repairs are essential. For this reason, there is actually no method for effectively suppressing the reaction between the refractory and the molten metal and the penetration of the molten metal into the refractory.

On the other hand, in the present technical field, almost no effort has been made in the past to increase the heat retention (heat insulation) of the refractory constituting the casting apparatus and suppress the energy consumption. In terms of reliability such as mechanical strength and erosion resistance to molten metal, this is due to the absence of an alumina cement-containing refractory castable or a refractory molded body that replaces the fired product. In spite of demands for reduction of CO ₂ emission and energy saving, there is a need for a refractory molded body for metal casting that can suppress heat consumption by improving heat retention (heat insulation).
In addition, alumina cement-containing refractory castables and fired products thereof are relatively high (heavy) with a bulk density of 1.0 to 3.0 g / cm ³ , so in applications where lightness such as a ladle for transportation is required. There was a technical problem that was not appropriate.

  Furthermore, when connecting multiple refractory molded bodies and using them as lining materials for members that come into contact with molten metal such as firewood, molten metal holding furnaces, ladles, etc., a paste-like amorphous refractory composition is used for joints, etc. However, even for this paste-like amorphous refractory composition, as with the refractory molded article, there is no need for post-treatment such as coating, and metal adhesion due to penetration of metal melt and surface reaction is suppressed, It is required to have high heat retention (heat insulation) and light weight.

  Accordingly, the present invention eliminates the need for post-treatment such as coating, suppresses metal adhesion due to penetration of metal melt and surface reaction, has high heat retention (heat insulation), and is a lightweight fire-resistant molded article for metal casting. It is an object of the present invention to provide a method for easily producing a fire-resistant molded article for metal casting, an amorphous fire-resistant composition, and a molten metal holding member for metal casting.

In order to achieve the above object, the present inventors have conducted extensive studies, and as a result, 9-95% by mass of inorganic fibers, 4-20% by mass of silica binder, calcium fluoride, magnesium fluoride, calcium oxide, oxidation Based on this knowledge, the inventors have found that the above object can be achieved by a refractory molded body for metal casting made of a material containing 1 to 87% by mass of one or more ion-binding substances selected from magnesium, barium oxide and barium sulfate. The present invention has been completed.

That is, the present invention
(1) 9 to 95% by mass of inorganic fiber, 4 to 20% by mass of silica binder, one or more ion binding properties selected from calcium fluoride, magnesium fluoride, calcium oxide, magnesium oxide, barium oxide and barium sulfate A fire-resistant molded article for metal casting, characterized by comprising a material containing 1 to 87% by mass of a substance,
(2) A method for producing a refractory molded body for metal casting,
In solid content, inorganic fiber is 9 to 95% by mass, colloidal silica is 4 to 20% by mass in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide or precursor thereof, magnesium oxide or precursor thereof, barium oxide Or a slurry containing 1 to 87% by mass of one or more ion-binding substances selected from precursors thereof and barium sulfate,
A method for producing a refractory molded body for metal casting, characterized by dehydration molding;
(3) The method for producing a refractory molded body for metal casting according to the above (2), wherein the particle size of the colloidal silica is a median diameter of less than 0.1 μm and a 90% cumulative diameter of less than 0.2 μm.
(4) In the solid content, 9 to 95% by mass of inorganic fiber, 4 to 20% by mass of colloidal silica in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide or a precursor thereof, magnesium oxide or a precursor thereof An amorphous refractory composition comprising 1 to 87% by mass of one or more ion-binding substances selected from barium oxide or a precursor thereof and barium sulfate,
(5) A refractory molded body for metal casting according to (1) above or a refractory molded body for metal casting obtained by the method according to (2) or (3) above is used as an lining material. The present invention provides a molten metal holding member for metal casting.

According to the present invention, since the refractory molded body is made of a material containing a predetermined amount of an ion binding substance having a high ion binding property and a silica binder, the metal melt having a high reducing power and the oxygen supply to the metal melt are provided. The oxidation-reduction reaction of silica as a source proceeds rapidly, and a metal oxide film can be rapidly formed on the refractory surface. As a result, the metal oxide is formed on the surface before the penetration of the molten metal, so that the sticking of the metal and the penetration of the molten metal are suppressed, and the metal oxide itself is easily peeled off. It is possible to provide a refractory molded article that is suppressed in generation.
Further, according to the present invention, since the fireproof molded body is made of a material containing a predetermined amount of inorganic fibers together with an ion binding substance and a silica binder, the fireproof molded body has the necessary minimum strength and erosion resistance. In addition, it is possible to provide a fireproof molded article excellent in heat retention (heat insulation) and light weight.
Furthermore, according to this invention, the method of manufacturing the said fireproof molded object simply can be provided.
In addition, according to the present invention, when used as a joint of a refractory molded article, there is no need for post-treatment such as coating after construction, and metal adhesion due to penetration of metal melt or surface reaction is suppressed. Further, it is possible to provide an amorphous refractory composition having high heat retention (heat insulation) and light weight.
ADVANTAGE OF THE INVENTION According to this invention, the molten metal holding member for metal castings which has the said fireproof molded object as an lining material and was excellent in heat retention (heat insulation) and lightweight property can be provided.

(Fireproof molded body for metal casting)
First, the fire-resistant molded object for metal casting of this invention is demonstrated.
The fire-resistant molded article for metal casting of the present invention is selected from 9 to 95% by mass of inorganic fibers, 4 to 20% by mass of silica binder, calcium fluoride, magnesium fluoride, calcium oxide, magnesium oxide, barium oxide and barium sulfate. It consists of the material which contains 1-87 mass% of 1 or more types of ion binding substances.

  Inorganic fiber exhibits the function as an aggregate of the fire-resistant molded article obtained, and is not particularly limited as long as it exhibits this function. For example, glass fiber, glass wool, ceramic wool, rock wool, alumina 1 type or more chosen from a mineral fiber, a zirconia fiber, an aluminosilicate fiber, a biosoluble inorganic fiber, etc. can be mentioned.

In the present application document, the biosoluble inorganic fiber means an inorganic fiber having a physiological saline dissolution rate at 40 ° C. of 1% or more. Examples of the biosoluble inorganic fiber include inorganic fibers described in JP-A-2000-220037, JP-A-2002-68777, JP-A-2003-73926, or JP-A-2003-212596. That is, the total content of SiO ₂ and CaO is 85% by mass or more, 0.5 to 3.0% by mass of MgO and 2.0 to 8.0% by mass of P ₂ O ₅ , and Germany Inorganic fibers having a carcinogenicity index (KI value) of 40 or more according to hazardous substance regulations, inorganic fibers containing SiO ₂ , MgO and TiO ₂ as essential components, and inorganic fibers containing SiO ₂ , MgO and manganese oxide as essential components _and, SiO 2 fifty-two to seventy-two wt%, _Al less than 2 _{O 3} 3 wt%, MgO 0 to 7 wt%, CaO 7.5 to 9.5 _{wt%, B} 2 O 3 0 to 12 wt%, B O 0 to 4 wt%, SrO 0 to 3.5 _wt%, Na 2 O from 10 to 20.5 _wt%, the K 2 O 0.5 to 4.0 wt% and _P 2 _O 5 0 to 5 wt% and inorganic fibers _including, SiO 2 75-80 mass%, CaO + MgO 19 to _25% by _weight, can include one or more selected from inorganic fibers containing Al ₂ O 3 1 to 3 wt%.

The average fiber diameter of the inorganic fibers is preferably 1 to 50 μm, more preferably 1.5 to 10 μm, and further preferably 2 to 6 μm. If the average fiber diameter is less than 1 μm, the fiber is likely to break, so that the strength of the obtained fire-resistant molded article tends to be low, and if it exceeds 50 μm, the density of the fire-resistant molded article becomes low. The strength tends to be low. Moreover, it is preferable that the average fiber length of an inorganic fiber is 1-200 mm, It is more preferable that it is 2-50 mm, It is further more preferable that it is 10-50 mm. When the average fiber length is within the above range, it becomes easy to obtain a fireproof molded article having an appropriate density.
In addition, in this application document, an average fiber diameter means the average value when the diameter of 200 fibers is measured in the observation image by an electron microscope. Moreover, an average fiber length means the average value when the fiber length of 200 fibers is measured with a caliper.

In the fireproof molded article of the present invention, the inorganic fibers are contained in an amount of 9 to 95% by mass, preferably 15 to 90% by mass, and more preferably 20 to 90% by mass.
By providing the inorganic fiber content of 9 to 95% by mass, it is possible to provide a fire-resistant molded article having excellent heat retention (heat insulation) and light weight while having the minimum required strength and erosion resistance. it can.

  Since inorganic fibers have the properties of being lightweight and low density, when used as a constituent material of a fireproof molded body, conventionally, only a fireproof molded body that is brittle in mechanical strength and susceptible to corrosion by a molten metal such as aluminum is obtained. It was considered impossible. However, as a result of intensive studies by the present inventors, the use of a predetermined amount of inorganic fibers as a constituent material of a fire-resistant molded body together with an ion-binding substance and a silica binder has the minimum necessary strength and erosion resistance. The present inventors have found that a fire-resistant molded article that is excellent in heat retention (heat insulation) and reduced in weight can be produced, and has completed the present invention.

  In the refractory molded article of the present invention, the silica binder is preferably a dried or fired colloidal silica described later.

  In particular, the silica binder imparts sufficient shape retention and strength to the fireproof molded body obtained by dehydrating, drying and firing the raw materials, and exhibits the function of binding inorganic fibers together. At the same time, as an oxygen supply source to the molten metal, an oxide film (aluminum oxide film when the metal is aluminum) forming function of the molten metal is exhibited at the interface where the refractory and the molten metal are in contact.

  The fire-resistant molded article of the present invention contains 4 to 20% by mass of silica binder (silica), preferably 4 to 18% by mass, and more preferably 7 to 15% by mass.

  In the refractory molded article of the present invention, when the content of the silica binder is less than 4% by mass, it is difficult to quickly form an oxide film on the refractory surface, and it is difficult to obtain strength after firing. On the other hand, if it exceeds 20% by mass, the drainage at the time of dehydration molding, which will be described later, decreases, and the production efficiency tends to decrease.

  The fireproof molded article of the present invention contains at least one selected from calcium fluoride, magnesium fluoride, calcium oxide, magnesium oxide, barium oxide and barium sulfate as an ion binding substance. As the ion binding substance, calcium fluoride is preferred because it has the strongest ion binding ability.

  In the refractory molded body of the present invention, the ion-binding substance has a strong ionic bondability equal to or higher than that of the molten metal oxide, for example, aluminum oxide, and the interface where the refractory molded body and the molten metal are in contact. Therefore, it is used for the purpose of forming an oxide film of a molten metal. Since the ion binding substance has a larger oxide film forming effect as the ion binding property is stronger, even if the content in the mixture is small, a sufficient oxide film forming effect can be exhibited.

The ion-binding substance preferably has a small particle diameter, specifically, an average particle diameter of 0.15 mm or less is preferable, an average particle diameter of 0.10 mm or less is more preferable, and an average particle diameter of 0.050 mm. The following are more preferable. Moreover, it is preferable that the said average particle diameter is 0.001 mm or more.
When an ion-binding substance with a small particle size is used, the specific surface area of the ion-binding substance can be increased as a whole, so that an oxide film with appropriate peelability can be quickly formed on the surface of the fire-resistant molded body. can do.

  In the present application documents, the average particle size of the ion-binding substance means a value measured by a laser diffraction / scattering method using a particle size distribution meter.

  Moreover, it is preferable to use an ion-binding substance having a purity of 90% or more, and it is more preferable to use a substance having a purity of 99% or more.

  In the refractory molded article of the present invention, the ion-binding substance is contained in an amount of 1 to 87% by mass, preferably 4 to 30% by mass, and more preferably 7 to 20% by mass.

  When the content ratio of the ion-binding substance is less than 1% by mass, it becomes difficult to quickly form an oxide film of the molten metal at the interface where the refractory and the molten metal are in contact. On the other hand, when the content exceeds 87% by mass, a material having strong ionic bonding generally has a large volume expansion due to heating, so that the thermal shock resistance is lowered and the fire-resistant molded article obtained by thermal shock is easily cracked. In addition, since the content ratio of the ion binding substance (inorganic powder) with respect to the content ratio of the inorganic fibers becomes too high, the dehydration moldability is hindered during the production of the fire-resistant molded body described later. Moreover, since the content rate of a silica binder also reduces, the intensity | strength after baking is hard to be obtained. The refractory molded body of the present invention can rapidly form an oxide film of the molten metal at the interface where the obtained refractory molded body and the molten metal are in contact with each other by containing the ion binding substance and the silica binder in a specific ratio. it can.

  The fireproof molded article of the present invention may contain powdery fillers, aggregates, and organic binders as optional components, thereby improving the mechanical strength of the fireproof molded article.

  Examples of the filler and aggregate include silica, alumina, chamotte, titania, zirconia, silicon nitride, silicon carbide, cordierite, and wollastonite.

  Examples of the organic binder include starch, acrylic resin, polyacrylamide and the like. When the refractory molded article of the present invention contains an organic binder, sufficient shape retention and strength can be imparted to the refractory molded article obtained by dehydrating and drying the raw material, as will be described later. Among the organic binders, polyacrylamide is preferably used because it also functions as a flocculant during dehydration molding.

  The refractory molded article of the present invention preferably contains 0.1 to 80% by mass, more preferably 0.1 to 70% by mass, of filler and aggregate. Moreover, it is preferable to contain 0.05-15 mass% of organic binders, and it is more preferable to contain 0.5-5 mass%.

  The refractory molded article of the present invention is made of a material containing a predetermined amount of an ion-binding substance having a high ion-binding property and a silica binder, and is therefore a high reducing power metal melt and an oxygen supply source to the metal melt. The oxidation-reduction reaction of silica proceeds quickly, and a metal oxide film can be rapidly formed on the surface of the refractory molded body. As a result, since metal oxide is formed on the surface of the refractory molded body before the penetration of the molten metal occurs, the adhesion of the metal to the refractory molded body can be suppressed, and the penetration of the molten metal to the refractory molded body is suppressed. Furthermore, since the metal oxide itself is easily peeled off, damage to the fireproof molded body can be suppressed.

The fireproof molded body of the present invention has, for example, a bulk density of 0.2 to 0.9 g / cm ³ , and preferably 0.4 to 0.8 g / cm ³ . A normal refractory molded article using alumina cement usually has a bulk density of 1.0 to 3.0 g / cm ³ , but the refractory molded article of the present invention has a predetermined amount together with an ion binding substance and a silica binder. Since it consists of material containing an inorganic fiber, weight reduction can be achieved.

  Moreover, the fireproof molded object of this invention is 0.1-0.3 W / mK in the heat conductivity in 700 degreeC, for example, Preferably it is 0.2-0.3 W / mK.

  Conventional refractory molded articles using alumina cement usually have a thermal conductivity of 0.4 to 1.7 W / mK at 700 ° C., but the refractory molded article of the present invention has an ion binding substance and a silica binder. Since it consists of a material containing a predetermined amount of inorganic fibers, it is possible to reduce the thermal conductivity of the refractory molded body and improve the heat retention (heat insulation).

  Moreover, the refractory molded body of the present invention has, for example, a bending strength of 0.2 to 2.0 MPa, preferably 0.6 to 2.0 MPa.

  Thus, since the fire-resistant molded article of the present invention is made of a material containing a predetermined amount of inorganic fibers together with an ion-binding substance and a silica binder, it has the minimum necessary strength and erosion resistance, Excellent heat retention (heat insulation) and light weight can be exhibited.

  The fireproof molded body of the present invention can be produced by dehydrating the raw material in the method for producing a fireproof molded body to be described later.In the present application, the fireproof molded body includes those dried after dehydration molding, Further, a fired product obtained by firing treatment is also included. Even a refractory molded body that is not subjected to a firing treatment after dehydration molding can be placed in a desired position as a refractory material, and can be made into a fired product by simultaneously heating the refractory material during metal casting.

  The fireproof molded article of the present invention can be preferably produced by the method for producing a fireproof molded article of the present invention.

  The refractory molded body of the present invention is used, for example, as a lining material for constructing a molten metal holding member for metal casting that comes into contact with molten metal such as firewood, a molten metal holding furnace, a ladle, etc. in a casting apparatus for non-ferrous metals such as aluminum and magnesium. It can be preferably used.

(Method for producing refractory molded body for metal casting)
Next, the manufacturing method of the fire-resistant molded object for metal casting of this invention is demonstrated.
The method for producing a fire-resistant molded article for metal casting according to the present invention comprises 9 to 95% by mass of inorganic fibers and 4 to 20% by mass of colloidal silica in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide in the solid content. Alternatively, a slurry containing 1 to 87% by mass of one or more ion-binding substances selected from a precursor thereof, magnesium oxide or a precursor thereof, barium oxide or a precursor thereof and barium sulfate is dehydrated and molded. Is.

  In the method for producing a refractory molded body of the present invention, the inorganic fiber exhibits a function as an aggregate of the obtained refractory molded body, and examples thereof include those described above.

In the manufacturing method of the fireproof molded object of this invention, 9-95 mass% is contained in the solid content which comprises an inorganic fiber, It is preferable that 15-90 mass% is contained, and 20-90 mass% is contained. It is more preferable.
As will be described later, in the method for producing a refractory molded article of the present invention, the content ratio of the inorganic fibers in the mixture means a ratio of the entire solid content excluding moisture in the slurry.

  In the method for producing a refractory molded article of the present invention, colloidal silica includes silica particles or hydrates dispersed in water in a colloidal form, a median diameter (d50) of less than 0.1 μm, and a 90% integrated diameter (d90). ) Is preferably less than 0.2 μm, more preferably a median diameter (d50) of 0.01 μm or more and less than 0.1 μm, and a 90% cumulative diameter (d90) of 0.02 μm or more and less than 0.2 μm.

  Colloidal silica gives sufficient shape retention and strength to the obtained fire-resistant molded article, particularly when a raw material is dehydrated, dried and fired to produce a fire-resistant molded article. In addition to serving as a binder to bind inorganic fibers together, as an oxygen supply source to the molten metal, an oxide film of the molten metal (if the metal is aluminum, an aluminum oxide film at the interface between the refractory and the molten metal) ) Demonstrate the forming function. When the median diameter (d50) of the colloidal silica is less than 0.1 μm and the 90% cumulative diameter (d90) is less than 0.2 μm, the surface area of the silica increases after molding, and the metal melt having high reducing power and the oxidation of the silica The reduction reaction easily proceeds quickly, and an oxide film is easily formed on the surface of the refractory. On the other hand, if the median diameter (D50) of colloidal silica is 0.1 μm or more, or if the 90% cumulative diameter (d90) is 0.2 μm or more, it becomes difficult to form an oxide film quickly, and the resulting fireproof molded article It becomes easy for metal to stick to the surface.

  In the present application document, the median diameter (D50) refers to a particle diameter that is 50% integrated from the finest with respect to the particle size distribution, and the 90% integrated diameter (d90) is fine with respect to the particle size distribution. This means the particle size that is 90% integrated. The particle size of colloidal silica can be determined by a laser diffraction / scattering method for calculating the particle size distribution (particle size) from the light intensity distribution scattered from the particles.

  In the method for producing a refractory molded article of the present invention, the colloidal silica is contained in a solid content constituting the slurry in an amount of 4 to 20% by mass, preferably 4 to 18% by mass, preferably 7 to 15% by mass in terms of silica. % Is more preferable.

  Colloidal silica is a colloidal product in which silica particles or hydrates thereof are dispersed in water. In this application document, the content of the colloidal silica is converted to silica in the total solid content excluding the water content of the slurry. It means mass ratio.

  When the content of colloidal silica in the solid content constituting the slurry is less than 4% by mass in terms of silica, it is difficult to form an oxide film on the surface of the refractory quickly, and strength after firing is also obtained. It's hard to be done. On the other hand, if it exceeds 20% by mass, the drainage at the time of dehydration molding is lowered, and the production efficiency tends to be lowered.

  In the method for producing a refractory molded body of the present invention, the slurry contains calcium fluoride, magnesium fluoride, calcium oxide or a precursor thereof, magnesium oxide or a precursor thereof, barium oxide or a precursor thereof as an ion binding substance, and 1 type or more chosen from barium sulfate is included. As the ion binding substance, calcium fluoride is preferred because it has the strongest ion binding ability.

  An example of the calcium oxide precursor is calcium carbonate. Moreover, magnesium carbonate is mentioned as a precursor of magnesium oxide. Moreover, barium carbonate is mentioned as a precursor of barium oxide. Since these precursors are easily decomposed by heating, they exist as calcium oxide, magnesium oxide, and barium oxide in the dried refractory molded body or the heated refractory fired body, respectively.

  In the method for producing a refractory molded body according to the present invention, the ion-binding substance has a strong ionic bonding property equal to or higher than that of a molten metal oxide, for example, aluminum oxide. It is used for the purpose of forming an oxide film of molten metal at the contact interface. Since the ion binding substance has a larger oxide film forming effect as the ion binding property is stronger, even if the content in the mixture is small, a sufficient oxide film forming effect can be exhibited.

  The details of the particle size of the ion-binding substance, the method of measuring the particle size, and the purity are the same as those described in the description of the fireproof molded body of the present invention.

  In the method for producing a refractory molded article of the present invention, the ion-binding substance is contained in the solid content constituting the slurry in an amount of 1 to 87% by mass, preferably 4 to 30% by mass, and preferably 7 to 20% by mass. More preferably it is included.

When the content ratio of the ion-binding substance is less than 1% by mass, it becomes difficult to quickly form an oxide film of the molten metal at the interface where the refractory and the molten metal are in contact. On the other hand, when the content exceeds 87% by mass, a material having strong ionic bonding generally has a large volume expansion due to heating, so that the thermal shock resistance is lowered and the fire-resistant molded article obtained by thermal shock is easily cracked. In addition, the content ratio of the ion-binding substance (inorganic powder) with respect to the content ratio of the inorganic fibers becomes too high, which hinders the dehydration moldability. Moreover, since the amount of silica binder is also reduced, it is difficult to obtain strength after firing. In the method for producing a refractory molded body of the present invention, an oxide film of a molten metal is formed at the interface where the refractory molded body and the molten metal are in contact with each other by blending an ion binding substance and colloidal silica in a specific ratio in the slurry. Can be formed quickly.
In addition, in the manufacturing method of the fireproof molded object of this invention, the content rate of an ion binding substance means the mass ratio which occupies for the whole solid content except the water | moisture content of the slurry.

In the method for producing a refractory molded body of the present invention, the slurry may contain a powdery filler, an aggregate, and an organic binder as optional components. Can be improved.
Specific examples and blending amounts of the filler, aggregate, and organic binder are the same as those described in the explanation of the fire-resistant molded article of the present invention.

  In the method for producing a refractory molded body of the present invention, the liquid medium forming the slurry is not particularly limited, and examples thereof include water and polar organic solvents. Examples of the polar organic solvent include monovalent alcohols such as ethanol and propanol. And divalent alcohols such as ethylene glycol. Among these liquid media, water is preferable in consideration of the working environment and environmental load. Moreover, it does not restrict | limit especially as water, Distilled water, ion-exchange water, tap water, groundwater, industrial water etc. are mentioned.

  The solid content concentration in the slurry is preferably from 0.1 to 10% by mass, more preferably from 0.3 to 10% by mass, and even more preferably from 1 to 8% by mass. If the slurry concentration is less than 0.1% by mass, the amount of water to be removed in the dehydration molding process is excessive, which is inefficient. If it exceeds 10% by mass, the solid content is uniformly dispersed in the slurry. It becomes difficult to do. In addition, the film layer forming agent described below shall be contained in the solid content in the slurry.

The slurry may further contain a coating layer forming agent.
Examples of the coating layer forming agent include inorganic compounds such as phosphates, molybdenum compounds, and zinc compounds, and organic compounds such as polyamidine compounds and ethyleneimine compounds. Examples of the phosphate include aluminum tripolyphosphate, aluminum dipolyphosphate, aluminum metaphosphate, zinc phosphate, and calcium phosphate. Examples of the molybdenum compound include zinc molybdate, aluminum molybdate, calcium molybdate, phosphorus, and the like. Examples of the zinc compound include zinc oxide. Examples of the polyamidine compound include acrylamide, acrylonitrile, N-vinylacrylamidine hydrochloride, N-vinylacrylamide, and vinylamine hydrochloride. N-vinylformamide copolymer and the like, and examples of the ethyleneimine compound include aminoethylene and dimethyleneimine.

  In the method for producing a refractory molded body of the present invention, when a biosoluble inorganic fiber is used as the inorganic fiber, a coating layer is rapidly formed on the surface of the biosoluble inorganic fiber by blending a coating layer forming agent in the slurry. Thus, deterioration due to contact with a liquid medium such as water can be suppressed.

  In the method for producing a refractory molded body of the present invention, the order of mixing raw materials such as inorganic fibers, colloidal silica, and ion-binding substance in the liquid medium at the time of slurry formation is not particularly limited. What is necessary is just to mix in a medium. On the other hand, when the slurry contains the coating layer forming agent, it is preferable to mix the raw material such as inorganic fibers after mixing the coating layer forming agent in the liquid medium in advance when preparing the slurry. By mixing in advance, a coating layer can be rapidly formed on the surface of the inorganic fiber.

In the method for producing a refractory molded body of the present invention, the slurry is subjected to a dehydration molding process, and the liquid medium is removed.
In the method for producing a refractory molded article of the present invention, the slurry may contain a medium other than water as the liquid medium. However, in the present application document, the removal of the liquid medium other than water is also referred to as dehydration molding. .

  The dehydration molding is performed by, for example, a suction dehydration molding method, a pressure dehydration molding method, or a suction pressure dehydration method in which the slurry is poured into a molding die having a net installed at the bottom and the liquid medium such as water is sucked. be able to.

In the method for producing a refractory molded body of the present invention, when the slurry is conveyed to a molding die or the like, a pump or the like may be used, or the molding die is disposed at the lower part of the tank containing the slurry, and the slurry It may be conveyed by its own weight.
A dehydrated molded product having a shape similar to the fire-resistant molded product to be obtained is suitable, and examples thereof include a cylindrical shape, a bottomed cylindrical shape, a board shape, and a block shape.

  The obtained dehydrated molded product is preferably dried using a dryer or the like. The drying temperature is preferably 40 to 180 ° C, more preferably 60 to 150 ° C, and still more preferably 80 to 120 ° C. The drying time is preferably 6 to 48 hours, more preferably 8 to 40 hours, and further preferably 10 to 36 hours. In addition, examples of the atmosphere during drying include an air atmosphere, an oxygen atmosphere, and a nitrogen atmosphere.

In the method for producing a refractory molded article of the present invention, the dehydrated molded product may be further subjected to a firing treatment after being dried.
The firing temperature is preferably 600 to 1300 ° C, and more preferably 700 to 900 ° C. The atmosphere during firing is not particularly limited, but is preferably an air atmosphere, an oxygen atmosphere, or a nitrogen atmosphere. The firing time is preferably 0.5 to 4 hours.

  By performing the baking treatment, degreasing in the molded body and shrinkage during actual use can be prevented.

  In this way, a fire-resistant molded article having a desired shape excellent in thermal shock resistance, strength, erosion resistance, and penetration resistance can be obtained.

When a calcium oxide precursor, a magnesium oxide precursor, and a barium oxide precursor are used as the ion binding substance, these ion binding substances are calcium oxide, Present as magnesium oxide and barium oxide.
The details of the fireproof molded body to be obtained are as described in the description of the fireproof molded body of the present invention.
According to the method for producing a refractory molded body of the present invention, there is no need for post-treatment such as coating, metal penetration due to molten metal and surface adhesion is suppressed, heat retention (heat insulation) is high, and lightweight. A simple fire-resistant molded article for metal casting can be easily produced.

(Amorphous refractory composition)
Next, the amorphous refractory composition of the present invention will be described.
The amorphous refractory composition of the present invention comprises 9 to 95% by mass of inorganic fiber and 4 to 20% by mass of colloidal silica in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide or a precursor thereof in the solid content. 1-87 mass% of 1 or more types of ion binding substances chosen from magnesium oxide or its precursor, barium oxide or its precursor, and barium sulfate are included.

  In the amorphous refractory composition of the present invention, the inorganic fiber can be the same as that described in the description of the refractory molded body of the present invention, and the colloidal silica can be used to produce the refractory molded body of the present invention. The same substances as mentioned in the explanation of the method can be mentioned, and the ion-binding substance can be the same as those mentioned in the explanation of the fireproof molded article of the present invention and the method of producing the fireproof molded article of the present invention. Can be mentioned.

The amorphous refractory of the present invention contains 9 to 95% by mass of inorganic fibers in the solid content, preferably 15 to 90% by mass, and more preferably 20 to 90% by mass.
When the content ratio of the inorganic fiber is 9 to 95% by mass in the solid content, heat retention (heat insulation) and the construction material (refractory material) are given the necessary minimum strength and erosion resistance after construction. An amorphous refractory composition capable of imparting light weight can be provided.

The amorphous refractory composition of the present invention contains colloidal silica in a solid content of 4 to 20% by mass, preferably 4 to 18% by mass, and more preferably 7 to 15% by mass in terms of silica.
Colloidal silica gives sufficient shape retention and strength to the construction by treating it at a high temperature during the construction of the irregular refractory composition or during use after construction, and binds inorganic fibers together. In addition to exhibiting the function of forming the metal melt, it also functions as an oxygen supply source to the molten metal at the interface where the work piece and the molten metal are in contact with each other.

  In the amorphous refractory composition of the present invention, if the content of colloidal silica is less than 4% by mass in terms of silica in the solid content, it is difficult to quickly form an oxide film on the surface of the construction after construction. Thus, the strength after firing becomes difficult to obtain, and if it exceeds 20% by mass, the production efficiency tends to decrease.

  The amorphous refractory of the present invention contains 1 to 87% by mass, preferably 4 to 30% by mass, more preferably 7 to 20% by mass, in terms of silica, of the ion-binding substance in terms of silica. .

  When the content ratio of the ion-binding substance is less than 1% by mass, it is difficult to quickly form an oxide film of the molten metal at the interface where the work piece and the molten metal are in contact. On the other hand, when the amount exceeds 87% by mass, a material having strong ionic bonding generally has a large volume expansion due to heating, so that the thermal shock resistance is lowered and the construction obtained by thermal shock is easily cracked, and the silica binder is contained. Since the ratio also decreases, it becomes difficult to obtain a desired strength after firing. The amorphous refractory composition of the present invention rapidly forms an oxide film of the molten metal at the interface where the obtained refractory molded body and the molten metal are in contact with each other by containing the ion binding substance and the silica binder in a specific ratio. be able to.

  In the refractory molded body of the present invention, the ion binding substance has a strong ion binding property equal to or higher than that of the molten metal oxide, for example, aluminum oxide, at the interface between the construction object and the molten metal. It is used for the purpose of forming an oxide film of molten metal. Since the ion binding substance has a larger oxide film forming effect as the ion binding property is stronger, even if the content in the mixture is small, a sufficient oxide film forming effect can be exhibited.

The amorphous refractory composition of the present invention may contain, as an optional component, a powdery filler, aggregate, organic binder, and a flocculant, thereby improving the mechanical strength of the refractory molded body. Can do.
Specific examples of the filler, the aggregate, the organic binder, and the flocculant are the same as those described in the description of the fireproof molded article of the present invention. This is the same as described in the description of the fireproof molded article of the present invention.

  In addition, the amorphous refractory composition of the present invention may contain additives such as a coating layer forming agent, a pH adjuster, a thickener, a dispersant, and an antiseptic.

Examples of the coating layer forming agent include the same ones as mentioned in the description of the method for producing a refractory molded article of the present invention.
Examples of the pH adjuster include buffer solutions such as a phthalate standard solution (Selensen buffer solution) that is a pH 4 standard solution and a neutral phosphate standard solution that is a pH 7 standard solution. Examples of the acid include acetic acid, Formic acid and the like can be mentioned.
It is preferable that content of a buffer solution or an acid is the quantity which makes pH of an amorphous refractory composition 4 to 8.5.
Examples of the thickener include hydroxyethyl cellulose and sodium acrylate polymer, examples of the dispersant include carboxylic acids, polyhydric alcohols and amines, and examples of the preservative include a nitrogen atom or Mention may be made of inorganic or organic compounds having a sulfur atom.

  Furthermore, in the amorphous refractory composition of the present invention, when the inorganic fiber is a biosoluble fiber, it preferably contains an organic fiber. Examples of organic fibers include natural fibers such as pulp, cotton and hemp, and hydrophobic treated products of synthetic fibers such as vinylon, rayon, polypropylene and polyethylene.

  In the amorphous refractory composition of the present invention, examples of the irregular shape that is a refractory shape include a paste obtained by mixing a solid solvent with a liquid solvent.

  Although it does not restrict | limit especially as a liquid solvent which forms a paste-like thing, Water and a polar organic solvent are mentioned, As a polar organic solvent, bivalent alcohols, such as monohydric alcohols, such as ethanol and propanol, ethylene glycol, etc. Kind. Among these liquid media, water is preferable in consideration of the working environment and environmental load. Moreover, it does not restrict | limit especially as water, Distilled water, ion-exchange water, tap water, groundwater, industrial water etc. are mentioned.

  The viscosity of the paste, that is, the solid content concentration in the solvent is appropriately determined in consideration of the purpose of use and workability. For example, the content of the solvent is preferably 50 to 800% by mass, more preferably 100 to 800% by mass, with respect to 100% by mass of the solid material of the amorphous refractory composition of the present invention. More preferably, it is -500 mass%. If the solvent content is less than 50% by mass, the fluidity of the amorphous refractory composition is lowered, so that the workability is deteriorated, and the mechanical strength, particularly the bending strength, of the construction is lowered. In addition, if the solvent content exceeds 800% by mass, the consistency of the amorphous refractory composition increases, so that the paste-like composition drips during construction, and shrinkage of the construction such as joints due to drying increases. .

  The amorphous refractory composition of the present invention is used, for example, as a joint for a refractory molded body used for a lining material of a member that comes into contact with a molten metal such as firewood, a molten metal holding furnace, a ladle, etc. A construction having an arbitrary shape can be obtained. Except for the fact that this construction is constructed while taking an arbitrary shape during construction of the irregular refractory composition, the composition and physical properties of the constituent materials can be regarded as the refractory molded body of the present invention, Because it is made of a material containing a predetermined amount of an ion-binding substance having high binding properties and silica, the redox reaction of silica, which is an oxygen supply source to the molten metal with a high reducing power, and oxygen is rapidly progressing. A metal oxide film can be rapidly formed on the surface of the construction such as. As a result, since metal oxide is formed on the surface of the work before the penetration of the molten metal occurs, the adhesion of the metal to the work can be suppressed, and the penetration of the molten metal to the work is suppressed. Since the oxide itself is easy to peel off, damage to the construction can be suppressed.

  The amorphous refractory composition of the present invention is used as a joint of a lining material for constructing a member that comes into contact with a molten metal such as a firewood, a molten metal holding furnace, and a ladle in a casting apparatus for non-ferrous metals such as aluminum and magnesium. It can be preferably used.

Next, a method for producing the amorphous refractory composition of the present invention will be described.
As a method for producing the amorphous refractory composition of the present invention, it can be produced by mixing a constituent material such as the inorganic fiber, colloidal silica, ion-binding substance, etc. with a liquid solvent.

  The composition amount of the amorphous refractory composition and the amount of the solvent are as described above.

  As a preferred method for producing the amorphous refractory composition of the present invention, an inorganic fiber is added to a liquid mixture of a liquid solvent and a coating layer forming agent, and then colloidal silica and an ion-binding substance are added. A method of adding other compounding ingredients such as a thickener and preservative is preferred. Moreover, when mix | blending a pH adjuster, the method of adding an inorganic fiber to the liquid mixture of a solvent, a coating layer forming agent, and a pH adjuster, and adding another compounding component after that is preferable.

  Examples of the method of mixing the constituent material and the solvent include a method of kneading with a kneader such as a kneader or a pressure kneader. The kneading time is preferably 0.1 to 1.0 hour, and the kneading temperature is preferably 5 to 40 ° C.

(Melt holding member for metal casting)
Next, the molten metal holding member for metal casting according to the present invention will be described.
The molten metal holding member for metal casting of the present invention is characterized by having as a lining material the refractory molded body for metal casting of the present invention or the refractory molded body for metal casting obtained by the method of the present invention.

  The molten metal holding member for metal casting according to the present invention is a member used at a location where the molten metal is brought into contact with the molten metal in the metal casting apparatus, and specifically includes a slag, a molten metal holding furnace, a ladle and the like.

The molten metal holding member for metal casting usually has a metal casing and a lining material as constituent members.
The shape of the metal casing can be an arbitrary shape corresponding to the shape of the molten metal holding member for metal casting. For example, when the molten metal holding member for metal casting is a ladle, the metal casing has a thickness of 2 to 10 mm. It is preferable to use a lining material having a thickness of 50 to 200 mm with respect to the casing.

  The case where the molten metal holding member for metal casting is a ladle will be described as an example. As a ladle, a bottomed cylindrical pan body having a molten metal inlet and a pouring port and an opening and closing capable of sealing the molten metal inlet It has a free upper lid and an openable and closable pouring lid that can seal the molten metal extraction port. Examples thereof include those having a fire-resistant molded article for metal casting of the invention or a fire-resistant molded article for metal casting obtained by the method of the present invention. As said ladle, what has the said lining material in the whole inner surface of a pan main body, an inlet, and a spout is preferable.

  Since the molten metal holding member for metal casting of the present invention has the fireproof molded body of the present invention or the fireproof molded body obtained by the method of the present invention as a lining agent, it has the minimum necessary strength and erosion resistance. However, it is possible to improve heat retention (heat insulation) and reduce weight.

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.
In the following Examples and Comparative Examples, the colloidal silica particle size and the average particle size of the ion-binding substance were measured using a nanoparticle size distribution measuring device SALD-7100 (measurement range: 0.01 to 300 μm) (Shimadzu Corporation). Measured by the laser diffraction / scattering method. The bending strength (MPa) is measured according to JIS R 2553, and the 700 ° C. thermal conductivity (W / mK) is measured according to JIS A 1412 (protective hot plate method).

Example 1
1. Slurry Forming Step As shown in Table 1, 77.9% by mass of aluminosilicate fiber (fine flex bulk fiber manufactured by NICHIAS), median diameter (d50) of 0.02 μm, 90% integrated diameter (d90) of 0.001. 04 μm of colloidal silica in terms of silica, 8.7% by mass, calcium fluoride (average particle size 45 μm) 8.7% by mass, starch (Nippon Chemical Co., Ltd. Petrosize J) 4.3% by mass, polyacrylamide ( Polystron 311 manufactured by Arakawa Chemical Industries, Ltd.) To 100 parts by mass of the raw material consisting of 0.4% by mass, water was further added and stirred so that the slurry concentration became 3% by mass to prepare a slurry.

2. Molding step The slurry was poured into a mold having a net installed at the bottom, and water was dehydrated by sucking water in the slurry to obtain a plate-shaped dehydrated molded product.
Subsequently, it dried at 100 degreeC for 24 hours, and the flat processed material was obtained.

3. Firing step The obtained dried product is calcined at 700 ° C. for 3 hours in a heating furnace in an air atmosphere to obtain a target flat refractory molded body (length 200 mm, width 200 mm, thickness 50 mm). It was.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 2)
A fireproof molded article was obtained in the same manner as in Example 1 except that in the slurry forming step, 8.7% by mass of magnesium fluoride was used instead of 8.7% by mass of calcium fluoride.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 3)
In the slurry formation step, the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 69.3% by mass, and instead of 8.7% by mass of calcium fluoride, 17.3% by mass of calcium oxide was used. In the same manner as in Example 1, a fireproof molded body was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

Example 4
In the slurry forming step, the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 69.3% by mass, and instead of 8.7% by mass of calcium fluoride, 17.3% by mass of magnesium oxide was used. In the same manner as in Example 1, a fireproof molded body was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 5)
In the slurry forming step, the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 69.3% by mass, and barium sulfate 17.3% by mass was used instead of calcium fluoride 8.7% by mass. In the same manner as in Example 1, a fireproof molded body was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 6)
In the slurry forming step, the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 69.3% by mass, and barium oxide 17.3% by mass was used instead of 8.7% by mass of calcium fluoride. In the same manner as in Example 1, a fireproof molded body was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 7)
Example 1 except that the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 43.3% by mass and 34.6% by mass of silica particles (average particle size 6 μm) was used in the slurry forming step. In the same manner as above, a fireproof molded article was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Example 8)
Example 1 except that the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 17.3% by mass and 60.6% by mass of silica particles (average particle size 6 μm) was used in the slurry forming step. In the same manner as above, a fireproof molded article was obtained.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Comparative Example 1)
In the slurry forming step, a fireproof molded article was obtained in the same manner as in Example 1 except that the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 86.6% by mass and calcium fluoride was not used. It was.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Comparative Example 2)
In the slurry forming step, a refractory molded body was obtained in the same manner as in Example 1, except that 8.7% by mass of alumina sol (Nissan Chemical Co., Ltd.) was used instead of colloidal silica in terms of alumina.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) in the obtained fireproof molded article.

(Comparative Example 3)
In the slurry forming step, the blending amount of the aluminosilicate fiber was changed from 77.9% by mass to 86.6% by mass, calcium fluoride was not used, and alumina sol (manufactured by Nissan Chemical Co., Ltd.) was used instead of colloidal silica. A refractory molded article was obtained in the same manner as in Example 1 except that 8.7% by mass in terms of alumina was used.
Table 2 shows the composition of the obtained refractory molded article. In addition, Table 2 shows the bulk density (g / cm ³ ), bending strength (MPa), and 700 ° C. thermal conductivity (W / mK) of the obtained fireproof molded article.

(Evaluation)
The refractory molded bodies obtained in Examples 1 to 8 and Comparative Examples 1 to 3 were used as test bodies, and the following molten aluminum dripping test and molten aluminum immersion test were performed. The results are shown in Table 2.

<Aluminum melt drop test>
When the molten aluminum was dropped, it was measured whether or not an aluminum oxide film was formed in a short time at the interface between the specimen and the molten aluminum.
First, the plate-shaped test body was installed in an electric furnace so as to be horizontal, and a molten aluminum was dropped onto the test body from a close distance under a temperature condition of 700 ° C. and held for 1 hour. Then, after the inside of the electric furnace reached room temperature, the test specimen was taken out, and the oxidized state of the dropped aluminum was visually observed.
When the dropped aluminum is oxidized on the surface of the test specimen, the aluminum dropping portion of the test specimen loses luster and turns gray. Such a case was evaluated as "" (gray) ". In addition, when the dropped aluminum is not oxidized on the surface of the specimen, the aluminum dropping portion of the specimen is glossy. Such a case was evaluated as “×” (gloss).
According to this test method, since an oxide film layer is hardly formed on the surface of the molten aluminum immediately before contact with the test specimen, the molten aluminum without the oxide film layer can be brought into direct contact with the specimen. it can.

<Aluminum molten metal immersion test>
After immersing the test body in molten aluminum and then pulling up the test body, it was measured whether or not aluminum adhered to the test body.
First, aluminum was put into a crucible-shaped electric furnace and then melted at 700 ° C. The prismatic specimen is immersed in the melted aluminum. At this time, the upper surface portion of the test body is projected from the molten aluminum surface. During immersion, the electric furnace was maintained at 700 ° C., the test specimen was pulled up 24 hours after the start of immersion, and the pulled up specimen was cooled at room temperature and visually checked to evaluate as follows.
In the molten aluminum immersion test, when aluminum sticking is not observed on the test specimen, it is evaluated as “O” (none), and when aluminum sticking is observed on the specimen, “×” (full sticking) Attached) ”.
In the molten aluminum dropping test, the test time (700 ° C. holding time) is as short as 1 hour, so that even if aluminum is not oxidized, aluminum hardly sticks to the specimen. However, in the case of a test in which the molten aluminum is in contact with the test specimen for a long time such as an immersion test, aluminum that does not oxidize in a short period of time becomes adhered to the specimen.

From Table 2, the fireproof molded bodies obtained in Examples 1 to 8 have a bending strength of 0.3 to
While having a sufficient strength of 2.0 MPa, the heat conductivity at 700 ° C. is as low as 0.11 to 0.29 W / mK, so that it has sufficient heat retention (heat insulation) and the bulk density is 0.1. It turns out that it is lightweight with 29-0.75 g / cm < ³ >.

Further, from Table 2, the fire-resistant molded products obtained in Examples 1 to 8 formed an appropriate oxide film on the dropped portion of the molten aluminum in the aluminum dropping test, and in the aluminum immersion test. No adhesion of aluminum was observed on the surface of the test body. As described above, all of the refractory molded bodies obtained in Examples 1 to 8 have a rapid oxidation-reduction reaction between the molten metal having a high reducing power and the silica and the ion-binding material that are oxygen supply sources to the molten metal. It can be seen that an aluminum oxide film is rapidly formed at the interface between the refractory and the molten aluminum.
For this reason, according to the present invention, there is no need for post-treatment such as coating, metal penetration due to penetration of metal melt and surface reaction is suppressed, heat retention (heat insulation) is high, and light weight, ladle It can be seen that a refractory molded body that can be suitably used as a lining material for a molten metal holding member for metal casting such as the above can be easily produced.

  On the other hand, the fireproof molded bodies obtained in Comparative Examples 1 to 3 cannot form an appropriate oxide film on the dropping portion of the molten aluminum in the aluminum dropping test, and the aluminum immersion test. In FIG. 2, the sticking of aluminum was observed on the entire surface of the test body. For this reason, it turns out that all the refractory molded bodies obtained in Comparative Examples 1 to 3 do not rapidly form an aluminum oxide film at the interface between the refractory and the molten aluminum.

  According to the present invention, in a casting apparatus for non-ferrous metals such as aluminum and magnesium, for example, it can be suitably used as a lining material for constructing a member that comes into contact with a molten metal such as a firewood, a molten metal holding furnace, and a ladle. A fireproof molded body, a method for easily producing the fireproof molded body, an amorphous fireproof composition, and a molten metal holding member for metal casting can be provided.

Claims (5)

  9 to 95% by mass of inorganic fiber, 4 to 20% by mass of silica binder, 1 or more ion-binding substances selected from calcium fluoride, magnesium fluoride, calcium oxide, magnesium oxide, barium oxide and barium sulfate A fire-resistant molded article for metal casting, characterized by comprising a material containing ~ 87 mass%. A method of manufacturing a refractory molded body for metal casting,
In solid content, inorganic fiber is 9 to 95% by mass, colloidal silica is 4 to 20% by mass in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide or precursor thereof, magnesium oxide or precursor thereof, barium oxide Or a slurry containing 1 to 87% by mass of one or more ion-binding substances selected from precursors thereof and barium sulfate,
A method for producing a refractory molded body for metal casting, characterized by performing dehydration molding.   The method for producing a refractory molded body for metal casting according to claim 2, wherein the colloidal silica has a particle size of median diameter of less than 0.1 µm and 90% cumulative diameter of less than 0.2 µm.   In solid content, inorganic fiber is 9 to 95% by mass, colloidal silica is 4 to 20% by mass in terms of silica, calcium fluoride, magnesium fluoride, calcium oxide or precursor thereof, magnesium oxide or precursor thereof, barium oxide Or 1-87 mass% of 1 or more types of ion binding substances chosen from the precursor and barium sulfate are included, The amorphous refractory composition characterized by the above-mentioned.   A metal casting refractory molded body according to claim 1 or a metal casting refractory molded body obtained by the method according to claim 2 or claim 3 as a lining material. Element.