JP5208676B2 - Refractory composition - Google Patents

Description

  The present invention relates to lining of molten metal containers such as blast furnaces, kneading wheels, converters, ladles, smelting reduction furnaces, blast furnace outlet filling materials, nozzles provided in continuous casting equipment, immersion nozzles, long nozzles, sliding The present invention relates to a refractory composition suitably used for a non-ferrous metal melting furnace, such as a nozzle and a stopper.

  The refractory composition used for the above-mentioned application is prepared by blending a binder with a refractory aggregate and kneading it with a kneading apparatus such as a Simpson mill, Melanja, Eirich, Speed Maller, or Whirlmix. Generally, this is press-molded by an oil press, a friction press, a vacuum press, an isostatic press, or the like, and then heated, dried, cured, or fired to obtain a refractory. The above-described kneading apparatuses are properly used according to the form and properties of the binder and according to the kneading method.

  Here, the binder to be used includes solid and liquid binders. The properties required for a solid material are that it is easy to disperse in the refractory aggregate and hardly segregate, and is easily dissolved in the solvent used for adhering or coating on the surface of the refractory aggregate and is easy to dry. In addition, it is easy to be deformed when a load is applied during press molding, has good moldability, and has a high fixed carbon content when processed at high temperature and fired. In addition, it has good moldability when it is molded in liquid form, has a high fixed carbon content when it is processed and fired at high temperature, and further, a refractory composition (kneaded clay) prepared by kneading. ) If the wetness of the clay changes due to moisture absorption or drying before molding), the moldability will not be stable, the molding thickness will become thicker and thinner, and the yield of brick will decrease. Therefore, it is one of the required characteristics that it is difficult to absorb moisture between the preparation of the clay and the molding, and the solvent is difficult to evaporate.

  Among these characteristics, moldability and fixed carbon content are one of the important factors. Therefore, when a solid binder is used, a part of the low-boiling solvent used when blending the binder with the refractory aggregate is left in the refractory composition in order to impart plasticity, or the high-boiling solvent is used as a plasticizer. To the refractory composition to improve the fluidity of the refractory composition and improve the moldability. However, since the solvent is volatilized as a volatile substance when the refractory composition is molded and dried or fired, the solvent does not contribute to the fixed carbon amount of the refractory, and the fixed carbon amount is High and precise refractories cannot be obtained. Moreover, as the solvent in the clay evaporates, the wetness of the refractory composition changes and it is difficult to keep the moldability constant.

  In the case of a liquid binder, ethylene glycol or propylene glycol may be used to reduce the viscosity of the resin. In this case, the refractory composition is molded and dried or fired. At that time, ethylene glycol and propylene glycol are volatilized as volatiles, do not contribute to the fixed carbon content of the refractory, and a dense refractory with a high fixed carbon content cannot be obtained. Moreover, since ethylene glycol and propylene glycol easily absorb moisture, it is difficult to keep the moldability constant by changing the wetness of the refractory composition until it is molded.

  Furthermore, in any of these cases, when molding the refractory composition and drying / curing / firing, the solvents used to give moldability and the volatiles generated when the binder is cured or carbonized. In addition, there is a risk that the environment may be polluted, and the porosity of the refractory increases with solvents and volatiles, resulting in a decrease in oxidation resistance and corrosion resistance.

  Here, in the above-mentioned refractory composition, tars and pitches including coal tar pitch and petroleum tar pitch have been widely used as binders for a long time. This is because the carbon obtained after heat treatment of tar and pitch acts as a binder and is not easily wetted by molten slag and exhibits excellent corrosion resistance.

  However, the major drawback of using tar or pitch as a binder for the refractory composition is that tar and pitch are heated and volatile matter is scattered, and sufficient strength is obtained until the polycondensation reaction is almost completed. That is not. For this reason, it will receive various restrictions in manufacture and construction of a refractory. For example, in unfired or fired refractories using tar or pitch as a binder, it is necessary to remove most of the volatile components in tar and pitch and to promote carbonization by baking at 350 to 550 ° C. This baking process is based on the premise that the vapor pressure of volatile components in tar and pitch is suppressed to such an extent that the blistering phenomenon of the refractory does not occur, and the baking process takes a long time. It became a big problem in terms of production capacity and production cost. In addition, tar and pitch volatiles pollute the environment, and there is a problem that exhaust equipment is required.Further, refractory compositions containing tar and pitch as a binder component are poor in plasticity, so high pressure is required for molding. It was necessary to increase the amount of addition.

  On the other hand, in recent years, phenolic resins are frequently used as binders that can cope with the above problems of tar and pitch. Unlike tar and pitch, the phenol resin is a thermosetting compound, so that it develops strength from a low temperature range of 200 ° C. or less and does not need to be baked. However, since the phenolic resin is carbonized as it is by heating to become amorphous carbon, the refractory has a high porosity, which means that the oxidation resistance, corrosion resistance, and spalling resistance are inferior to tar and pitch. Has drawbacks.

  Therefore, if a phenol resin and tar or pitch can be used together as a binder, it is considered that both disadvantages can be compensated. However, tar and pitch are nonpolar, while phenol resin is highly polar, so both are poorly compatible, and even when mixed, they are separated as the temperature decreases, and both are evenly mixed. It is difficult to obtain a refractory by dispersing. It is also conceivable to use a solvent that uniformly dissolves the phenol resin and tar and pitch. However, when the solvent evaporates during heat curing, the binder component moves with the solvent, and the binder component does not disperse in the cured product. It becomes uniform and is not preferable.

Therefore, the present applicant has previously proposed a refractory composition in which a phenolic resin, tar, pitch, and a cyclic compound such as 2-furaldehyde are blended as a binder in a refractory aggregate (see Patent Document 1). In this product, since the cyclic compound acts as a solvent for dissolving the phenol resin and tar and pitch, respectively, the moldability can be improved, and since the cyclic compound is carbonized by firing, the amount of fixed carbon is high. A refractory with good corrosion resistance can be obtained.
JP 2003-89571 A

  And in the thing of said patent document 1, it is possible to increase the fixed carbon amount of a refractory by making cyclic compounds, such as 2-furaldehyde, react with a phenol resin. However, the amount of the curing agent (that is, hexamethylenetetramine) described in Patent Document 1 can only cure the phenol resin, and reacts a cyclic compound such as 2-furaldehyde with the phenol resin to produce a refractory. The amount of fixed carbon was not yet increased.

  The present invention has been made in view of the above points, and can further increase the amount of fixed carbon, and can provide a refractory composition having good oxidation resistance, spalling resistance, and corrosion resistance. Is intended to provide.

Refractory compositions according to the present invention, magnesia and carbon material as the refractory aggregate, the at least one preparative 2-furaldehyde phenol resin and tar and pitch as a binder, a compound which generates formaldehyde as a hardener of the binder Each containing what is chosen from a certain hexamethylenetetramine, tetraoxane, trioxane, and acetal resin , in a binder, phenol resin is 20-60 mass%, at least one of tar and pitch is 15-40 mass%, 2-furaldehyde Is a content ratio of 20 to 50% by mass, and the compounding amount of the compound that forms formaldehyde with respect to 100 parts by mass of the binder is 9.5 parts by mass or more.

  Further, the present invention is characterized in that the tar and pitch have a softening point of 30 to 400 ° C.

  Moreover, in this invention, said phenol resin is a solid, It is characterized by the above-mentioned.

  Moreover, in this invention, said phenol resin is a liquid, It is characterized by the above-mentioned.

  Further, in the present invention, at least one of the above-mentioned 2-furaldehyde and tar and pitch is blended at the same time when the phenol resin is blended with the refractory aggregate. .

  In the present invention, at least one of the above-mentioned phenol resin, tar and pitch, and any two kinds of 2-furaldehyde are mixed with the refractory aggregate in a mixed state in advance.

  In the present invention, at least one of the above-mentioned phenol resin, tar, and pitch, 2-furaldehyde, is mixed with the refractory aggregate in a premixed state.

  Further, in the present invention, 2-furaldehyde is characterized in that a part thereof is previously reacted with a phenol resin and at least one of tar and pitch.

  Moreover, in this invention, the reaction catalyst which reacts said phenol resin, at least one of tar and pitch, and 2-furaldehyde is contained, It is characterized by the above-mentioned.

  According to the present invention, 2-furaldehyde in the binder also acts as a solvent for dissolving the phenol resin and tar and pitch, respectively, especially phenol resin is 20 to 60% by mass, tar and pitch is 15 to 40% by mass, When the content ratio of 2-furaldehyde is 20 to 50% by mass, these can be dissolved with high compatibility and the moldability can be improved. In addition, the compounding amount of the compound that forms formaldehyde with respect to 100 parts by mass of the binder is 9.5 parts by mass or more, so that the phenol resin is cured by the compound that forms formaldehyde used as the curing agent, and 2 -Fluoraldehyde can be sufficiently polymerized by sufficiently reacting with phenol resin, tar or pitch, and a refractory having a high fixed carbon content and good corrosion resistance and spalling resistance can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described.

In the present invention, as the refractory aggregate, various kinds of materials generally used as refractory raw materials can be used, and any refractory raw material from coarse to fine powder can be blended and used. . For example, electrofused products such as electrofused magnesia, sintered products such as sintered magnesia, natural raw materials such as natural magnesia, bauxite, andalusite, sillimanite, and ultrafine powder materials such as calcined alumina and silica flour. Can be used. As the refractory aggregate, Al, Mg, Ca, Si, or one or more of these alloys can be blended and used. Further, various carbides, borides, nitrides such as SiC, B ₄ C, BN, Si ₃ N _{4 and the} like can be used as an antioxidant for the carbonaceous material.

  Among these, in the present invention, magnesia is used as at least a part of the refractory. This is because magnesia has a high melting point and excellent corrosion resistance among aggregates used for refractories. Moreover, as this magnesia, it is preferable to use a MgO content of 85% by mass or more. Magnesia having an MgO content of less than 85% by mass is not preferable because the fire resistance is lowered.

  Moreover, in order to improve corrosion resistance, the powder of the carbonaceous material with poor wettability with molten slag is mix | blended as a fireproof aggregate. The carbonaceous material may be any carbonaceous material such as natural graphite, artificial graphite, pitch, coke, carbon black, quiche graphite, mesophase carbon, and charcoal, but it should be as pure as possible. preferable.

  As described above, the present invention uses at least magnesia and a carbonaceous material as the refractory aggregate. In the refractory material, the content of magnesia is 60 to 99 mass%, and the content of the carbonaceous material is 1 to 40 mass. % Is desirable.

  A refractory composition can be obtained by blending and kneading a binder with these refractory aggregates. In the present invention, the binder includes three components of phenol resin, tar, pitch, and 2-furaldehyde. In addition, a curing agent and, if necessary, a reaction catalyst are blended. In the present invention, at least one of tar and pitch is used, that is, either tar or pitch is used alone, or both can be used in combination. Hereinafter, the meaning of “at least one of tar and pitch” is referred to as “tar pitch”.

  Here, what was prepared by making phenols and aldehydes react in presence of a reaction catalyst can be used for a phenol resin. Phenols mean phenol and derivatives of phenol. For example, in addition to phenol, trifunctional compounds such as m-cresol, resorcinol and 3,5-xylenol, and tetrafunctional compounds such as bisphenol A and dihydroxydiphenylmethane. Bifunctional o- or p such as o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, 2,4 or 2,6-xylenol -Substituted phenols can be mentioned, and also halogenated phenols substituted with chlorine or bromine can be used. Of course, in addition to selecting and using one of these, a plurality of types can be mixed and used.

  As the aldehyde, formalin in the form of an aqueous solution is optimal, but forms such as paraformaldehyde, acetaldehyde, benzaldehyde, trioxane, and tetraoxane can also be used. It can be used by replacing with aldehyde or furfuryl alcohol.

  The blending ratio of the above phenols and aldehydes is preferably set so that the molar ratio is in the range of 1: 0.5 to 1: 3.5. As a reaction catalyst, when preparing a novolac-type phenol resin, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, organic acids such as oxalic acid, paratoluenesulfonic acid, benzenesulfonic acid and xylenesulfonic acid, and acetic acid Zinc or the like can be used. When preparing a resol-type phenolic resin, an alkaline earth metal oxide or hydroxide can be used, and an aliphatic group such as dimethylamine, triethylamine, butylamine, dibutylamine, tributylamine, diethylenetriamine, or dicyandiamide. Primary, secondary, tertiary amine, aliphatic amines having aromatic rings such as N, N-dimethylbenzylamine, aromatic amines such as aniline and 1,5-naphthalenediamine, ammonia, hexamethylenetetramine, etc. Other divalent metal naphthenic acids and divalent metal hydroxides can also be used.

  The novolac-type phenol resin and the resol-type phenol resin may be used singly or may be used by mixing both in an arbitrary ratio. Various modified phenolic resins such as silicon modified, rubber modified, boron modified, etc. can be used. However, it does not matter whether the storage stability is stable or the refractory aggregate is acidic (for example, silica) or basic (for example, MgO). Considering the points that can be used, novolak type phenol resin is most preferable. As a curing agent for the novolac type phenol resin, a resol type phenol resin, an epoxy resin, an isocyanate compound, hexamethylenetetramine, trioxane, tetraoxane, an acetal resin, or the like can be used. Moreover, the curing agent of the resol type phenolic resin can be cured by heating to 100 ° C. or higher, but a curing agent can also be used. As the curing agent, novolac type phenolic resin, epoxy resin, isocyanate compound, organic Esters, alkylene carbonates, and the like can be used. In addition, as a curing catalyst for resol-type phenolic resins, inorganic acids such as hydrochloric acid and sulfuric acid, inorganic compounds such as aluminum chloride and zinc chloride, and organic acids such as benzenesulfonic acid, phenolsulfonic acid, and xylenesulfonic acid should be used. Can do.

  In order to improve the adhesion between the fireproof aggregate and the phenol resin, a coupling agent such as γ-aminopropyltriethoxysilane, γ- (aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane or the like is used. It can also be added and used.

  The tar pitch is preferably one having a small amount of insoluble benzene, which inhibits the uniformity of dispersion and reduces the function as a binder. The tar pitch can be a petroleum type or a coal type tar soft pitch, a reduced pressure pitch, a special pitch, a mesocarbon pitch, or the like, but it can be used from a liquid to a solid, but it is in a solid state and is JIS K 2425. Preferably, the softening point measured in accordance with is in the range of 30 to 400 ° C. Those with a softening point of less than 30 ° C have a large amount of volatile components, so the amount of fixed carbon is small, and those with a softening point of more than 400 ° C have many components that are insoluble in benzene, have few components as binders, and have a viscosity. Therefore, the moldability is inferior. Of course, the tar pitch is not limited to these, and a pitch having a high softening point and a liquid tar can be mixed and used, and a cup of phenol resin and tar pitch can be used. In order to promote the ring, a Lewis acid or the like can be added and mixed.

  The curing agent is used to cause a phenol resin to undergo a curing reaction and to react the phenol resin, tar pitch, and 2-furaldehyde to increase the molecular weight. As this hardening | curing agent, what produces | generates formaldehyde by thermally decomposing | disassembling is used, for example, hexamethylenetetramine, tetraoxane, trioxane, acetal resin etc. can be used.

  A reaction catalyst is used in order to accelerate | stimulate reaction of a phenol resin, tar pitch, and 2-furaldehyde. The reaction catalyst is not particularly limited, and an alkali metal or alkaline earth metal hydroxide, carbonate, oxide, acid catalyst, or amine catalyst can be used. In addition to using one of these alone, a plurality of types can be used in combination, but when using a plurality of types in combination, an alkali metal or alkaline earth metal oxide, hydroxide, carbonate, or acid is selected. It is preferable to use one or more of the above and an amine compound in combination. Furthermore, Lewis acids such as zinc chloride and aluminum chloride can be used as a reaction catalyst.

  Examples of alkali metal or alkaline earth metal hydroxides, carbonates and oxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, sodium carbonate, calcium carbonate, Examples thereof include barium oxide and calcium oxide.

  Acid catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, carboxylic acids such as oxalic acid, maleic acid, maleic anhydride, succinic acid and benzoic acid, paratoluenesulfonic acid, benzenesulfonic acid and xylenesulfonic acid. And sulfonic acid such as

  Examples of amine catalysts include aliphatic primary, secondary, and tertiary amines such as dimethylamine, triethylamine, butylamine, dibutylamine, tributylamine, diethylenetriamine, dicyandiamide, ethylenediamine, triethylenetetramine, and triethanolamine. N. Examples include aliphatic amines having an aromatic ring such as N-dimethylbenzylamine, aromatic amines such as aniline and 1,5-naphthalenediamine, and ammonia.

  And a refractory composition can be prepared by blending and kneading the above-mentioned phenol resin, tar pitch, 2-furaldehyde, a curing agent, and a reaction catalyst as a binder to the refractory aggregate. is there. As the phenol resin, either a solid resin or a liquid resin may be used. And 2-furaldehyde is a binder and also acts as a reactive solvent for dissolving the phenol resin and tar pitch, respectively, and can uniformly disperse the phenol resin and tar pitch. A refractory composition using both a phenol resin and tar pitch can be prepared.

  The blending amount of the binder with respect to the refractory aggregate is not particularly limited, but the total amount of phenol resin, tar pitch and 2-furaldehyde is 1 to 50 parts by mass with respect to 100 parts by mass of the refractory aggregate. It is preferable to set the range.

  And the ratio of the phenol resin in a binder, tar pitch, and 2-furaldehyde is 20-60 mass% of phenol resins, 15-40 mass% of tar pitches, and 20-50 mass% of 2-furaldehyde. It is set so that the total amount of the three components is 100% by mass. By setting the proportions of the phenol resin, tar pitch, and 2-furaldehyde within this range, the compatibility of these three components can be obtained satisfactorily and dissolved uniformly.

  Moreover, the compounding quantity of a hardening | curing agent is set to 9.5 mass parts or more with respect to 100 mass parts of total amounts of the phenol resin of a binder, tar pitch, and 2-furaldehyde. Thus, in this invention, by setting the compounding amount of the curing agent to 9.5 parts by mass or more with respect to 100 parts by mass of the binder, the curing agent is added in an excessive amount than consumed in the phenol resin curing reaction. This excess curing agent contributes to the reaction of phenolic resin with tar pitch or 2-furaldehyde to polymerize it, and in particular 2-furan having a -CHO group in the side chain. Aldehydes can be polymerized, and the fixed carbon content of the refractory can be increased. The upper limit of the blending amount of the curing agent is not particularly set, but practically, the upper limit is 25 parts by mass of the curing agent with respect to 100 parts by mass of the binder.

  Furthermore, the blending amount of the reaction catalyst is not particularly limited. preferable.

  Here, you may make it mix | blend 2-furaldehyde, tar pitch, a hardening | curing agent, and a reaction catalyst simultaneously, when mix | blending a phenol resin with a fireproof aggregate. At this time, the reaction catalyst may be blended separately from the phenol resin, tar pitch, and 2-furaldehyde, but is previously mixed with at least one of the phenol resin, tar pitch, and 2-furaldehyde. The reaction catalyst may also be blended when blending these with the refractory aggregate.

  Alternatively, the three types of tar pitch and 2-furaldehyde are premixed in the phenolic resin, and the curing agent and reaction catalyst are premixed therein, and these are premixed and blended into the refractory aggregate. It may be. Further, two types of phenol resin, tar pitch, and 2-furaldehyde may be mixed in advance and blended with the refractory aggregate simultaneously with the other type. When a solid resin is used as a phenol resin or tar pitch, it can be mixed with refractory aggregate in a liquid state by dissolving the phenol resin or tar pitch in 2-furaldehyde. When a liquid resin or tar pitch is used, it can be mixed with the refractory aggregate in a state where the viscosity of the phenol resin or tar pitch is lowered with 2-furaldehyde. The workability of mixing and kneading of phenol resin and tar / pitch to the material can be improved. Furthermore, by dissolving a phenol resin, tar pitch or reaction catalyst in 2-furaldehyde and heating, the phenol resin or tar pitch can be modified with 2-furaldehyde. A part of this can also be used in a state of reacting with phenol resin or tar pitch in advance.

  Here, 2-furaldehyde is easy to wet with refractory aggregates and the like, and easily penetrates into the details of the refractory composition. Therefore, the binder comprising 2-furaldehyde, phenolic resin and tar pitch is refractory. It can be uniformly mixed and kneaded with the aggregate. Also, 2-furaldehyde dissolves phenolic resin and tar pitch, and even if phenolic resin and tar pitch are dissolved at high concentration, the solution can maintain a low viscosity. There is no need to do it.

  And 2-furaldehyde works as a plasticizer of a refractory composition, and when shape | molding a refractory composition, a moldability becomes favorable. Moreover, since 2-furaldehyde has a high boiling point of 161.7 ° C., the evaporation of 2-furaldehyde from the refractory composition is small, and 2-furaldehyde has a higher moisture content in the air than aliphatic compounds. It absorbs very little moisture. Accordingly, the wetness of the refractory composition does not change and is stable from kneading and preparing the refractory composition to molding, and the moldability can be kept constant.

  Thus, after molding the refractory composition obtained by blending as described above, the molded product can be heated, dried, cured, or baked to obtain a refractory. It is. Here, it is not necessary to add a large amount of solvent as described above, and since 2-furaldehyde reacts and is fixed in the refractory, it is dried or fired after the refractory composition is molded. At the same time, the environment is less polluted with the solvent that volatilizes, and the porosity of the refractory increases due to the volatilization of the solvent, thereby preventing the corrosion resistance of the refractory from decreasing. In addition, the refractory composition contains a curing agent and a reaction catalyst for reacting phenol resin, tar pitch and 2-furaldehyde, so that phenol resin and tar pitch can be used during kneading and molding. And 2-furaldehyde can be reacted, and these components can be prevented from evaporating, the fixed carbon amount of the refractory can be increased sufficiently, and a dense refractory can be obtained. It can be done. Furthermore, 2-furaldehyde having a -CHO group in the side chain easily reacts with the phenol nucleus of the phenol resin to form a polymer, and also reacts with tar pitch to form a polymer by self-condensing itself. By being baked, it remains in the refractory as carbon, and the amount of fixed carbon of the refractory can be further increased.

  Next, the present invention will be specifically described with reference to examples.

(Examples 1-5)
A reaction vessel was charged with 940 parts by weight of phenol, 673 parts by weight of 37% by weight formalin, and 5.6 parts by weight of oxalic acid, refluxed for about 60 minutes, allowed to react for 180 minutes, and then reacted with water and unreacted phenol. Then, this was pulverized into a powder having a particle size of 100 μm or less to obtain a solid novolac-type phenol resin A having a softening point of 99 ° C.

  Further, a pitch A was obtained by pulverizing a vacuum pitch having a softening point of 110 ° C., a toluene insoluble content of 20.3% by mass, a quinoline insoluble content of 3.2% by mass, and a fixed carbon content of 60.1% by mass to a particle size of 100 μm or less. .

  And, as a refractory aggregate, 80 parts by mass of electrofused magnesia (MgO content: 98.3% by mass), 18 parts by mass of natural graphite having a purity of 98%, and 2 parts by mass of Al powder were charged into a mixer, Further, the above-described novolac type phenol resin A, the above pitch A, and hexamethylenetetramine as a curing agent were added in the formulation shown in Table 1, kneaded for 10 minutes, and then added with 2-furaldehyde (boiling point) at 70 to 80 ° C. 161.7 ° C.) was added in the formulation shown in Table 1, and these were kneaded for 20 minutes to obtain a wet kneaded material (kneaded clay). Table 1 shows the fixed carbon content measured in accordance with JIS K 6910 (1999) for a mixture of phenol resin, pitch, hexamethylenetetramine, and 2-furaldehyde mixed with this kneaded material.

Next, the day after the kneading of the kneaded clay, the kneaded clay was dried at 200 ° C. for 1 hour, and the volatile matter was measured. The clay of the next day of kneading was molded at 147 MPa (1500 kgf / cm ² ) using a hydraulic press, and the molded product was dried at 200 ° C. for 12 hours to obtain a brick. The bulk specific gravity and bending strength of this brick were measured and are shown in Table 1.

  The clay was put in a stainless bat, and the stainless bat was placed in a thermo-hygrostat set at a temperature of 30 ° C. and a humidity of 90% RH with the upper surface open, and left for one week. The volatile content of this clay was measured in the same manner as described above, and the bulk specific gravity and bending strength of the brick obtained from this clay in the same manner as above were measured.

(Example 6)
A reaction vessel was charged with 940 parts by weight of phenol, 567 parts by weight of formalin 567 parts by weight, and 5.6 parts by weight of oxalic acid, refluxed for about 60 minutes, allowed to react for 180 minutes, and then reacted with water and unreacted phenol. Was distilled off to obtain a solid novolac type phenol resin having a softening point of 80 ° C.

  Next, 25 parts by mass of 2-furaldehyde was added to 40 parts by mass of this novolac type phenol resin in the same reaction vessel, and mixed and dissolved at 100 ° C. for 120 minutes to obtain a novolac type phenol resin solution B. The viscosity of this novolac type phenolic resin solution B at 25 ° C. was 8.5 Pa · s.

  Then, to 100 parts by mass of the same fireproof aggregate as in Example 1, 7.8 parts by mass of the above-described novolac type phenol resin solution B (the resin content of the phenol resin is 4.8 parts by mass), pitch A4. 2 parts by mass and 1.2 parts by mass of hexamethylenetetramine as a curing agent were added, and this was put into a mixer and kneaded at 70 to 80 ° C. for 40 minutes to obtain a wet kneaded material (kneaded clay). . With respect to this clay, the amount of fixed carbon, the volatile matter after one day and one week, the bulk specific gravity, and the bending strength were measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
In a reaction vessel, 940 parts by weight of phenol and 1217 parts by weight of 37% by weight formalin are added, and 60 parts by weight of a 20% by weight aqueous caustic soda solution is added as a catalyst. The reaction is refluxed for 60 minutes, and the reaction is continued for 90 minutes. It was. Thereafter, the solution was immediately drained to 100 ° C. under a reduced pressure of 13300 Pa to obtain a semi-solid resol type phenol resin.

  Next, 20 parts by mass of pitch A of Example 1 and 45.0 parts by mass of 2-furaldehyde are added to 35 parts by mass of this resol type phenolic resin in the same reaction vessel, and mixed and dissolved at 40 ° C. for 5 hours. A resol-type phenol resin solution C in which the phenol resin and pitch were compatible was obtained. The viscosity of this resol type phenol resin solution C at 25 ° C. was 5.8 Pa · s.

  Then, to 100 parts by mass of the same fireproof aggregate as in Example 1, 12 parts by mass of the above-mentioned resol type phenol resin solution C (phenol resin solid content is 4.2 parts by mass, pitch is 2.4 parts by mass, 2-full Aldehyde is 5.4 parts by mass), and 1.2 parts by mass of hexamethylenetetramine is added as a curing agent, and this is put into a mixer and kneaded at 40 to 50 ° C. for 40 minutes to obtain a wet kneaded product (坏Sat) With respect to this clay, the amount of fixed carbon, the volatile matter after one day and one week, the bulk specific gravity, and the bending strength were measured in the same manner as in Example 1. The results are shown in Table 1.

(Examples 8 to 9)
A clay was obtained in the same manner as in Example 3 except that xylenesulfonic acid was added as a reaction catalyst in the amounts shown in Table 1. With respect to this clay, the amount of fixed carbon, the volatile matter after one day and one week, the bulk specific gravity, and the bending strength were measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Examples 1-7)
A clay was obtained in the same manner as in Example 1 except that the blending amounts shown in Table 2 were set. With respect to this clay, the amount of fixed carbon, volatile matter after one day and one week, bulk specific gravity, and bending strength were measured in the same manner as in Example 1, and the results are shown in Table 2.

  In said Examples 1-9 and Comparative Examples 1-7, the compatibility of phenol resin, pitch, and 2-furaldehyde was tested. The compatibility test was conducted as follows. First, a predetermined amount of phenol resin, pitch, and 2-furaldehyde set in Examples 1 to 9 and Comparative Examples 1 to 7 were weighed, heated to about 70 ° C., and mixed and dissolved. About 80 ml of the solution was placed in a 100 ml sample bottle and allowed to stand at room temperature for 3 days. After 3 days, the presence or absence of separation was visually confirmed, and a glass rod was inserted from the upper part of the sample bottle to confirm the presence or absence of a precipitate at the lower part. Those with no separation or precipitation were evaluated as “◯”, and those with separation or precipitation were evaluated as “x”.

  Moreover, in said Examples 1-9 and Comparative Examples 1-7, the sample was cut out from the brick produced on the day following kneading | mixing, and the spalling resistance test and the oxidation resistance test were done. The spalling resistance test was performed by immersing a test piece of 40 mm × 40 mm × 230 mm in hot metal iron at 1600 ° C. and water cooling five times, and examining the occurrence of cracks. The results were evaluated as “◎” for no crack, “◯” for crack occurrence, and “x” for crack and flaking. The oxidation resistance test was performed by firing a test piece of φ50 mm × 50 mm in an electric furnace at 1000 ° C. for 8 hours. The results were determined by cutting the sample after firing and measuring the thickness of the decarburized layer.

  Further, a 50 × 50 × 50 mm test piece was cut out from the brick produced on the next day of kneading, and the porosity after reduction baking at 1400 ° C. for 3 hours in a coke breeze was measured.

  Tables 1 and 2 show the blending and measurement / test results of Examples 1 to 9 and Comparative Examples 1 to 7.

  As can be seen in Tables 1 and 2, the clay of each example had less volatile content after one day and one week and stronger bending strength than the corresponding comparative example. In addition, each of the examples had a large amount of fixed carbon, and almost no change over time in the properties of the clay and the physical properties of the brick was observed. Furthermore, it was confirmed that a dense brick was produced with a low porosity after reduction firing, and the spalling resistance and oxidation resistance were also high.

Claims (9)

Hexamethylenetetramine, tetraoxane, trioxane, acetal, which is a compound that forms magnesia and carbonaceous materials as fireproof aggregates, phenol resin, at least one of tar and pitch, and 2-furaldehyde as binders, and formaldehyde as a curing agent for binders. What is selected from resins is contained, and in the binder, the phenol resin is 20 to 60% by mass, at least one of tar and pitch is 15 to 40% by mass, and 2-furaldehyde is 20 to 50% by mass. A refractory composition characterized in that the compounding amount of the formaldehyde-forming compound is 9.5 parts by mass or more with respect to 100 parts by mass of the binder.   The refractory composition according to claim 1, wherein the tar and pitch have a softening point of 30 to 400 ° C.   The refractory composition according to claim 1 or 2, wherein the phenol resin is solid.   The refractory composition according to claim 1 or 2, wherein the phenol resin is a liquid.   5. The compound according to claim 1, wherein at least one of 2-furaldehyde and at least one of tar and pitch is blended at the same time when the phenol resin is blended with the refractory aggregate. Refractory composition.   5. The refractory aggregate is mixed with at least one of phenolic resin, tar and pitch, and 2-furaldehyde in a state of being mixed in advance. 5. Refractory composition.   The refractory composition according to any one of claims 1 to 4, wherein at least one of phenol resin, tar, and pitch, and three types of 2-furaldehyde are mixed in advance in the refractory aggregate. object.   The refractory composition according to any one of claims 1 to 7, wherein a part of 2-furaldehyde is previously reacted with a phenol resin and at least one of tar and pitch. object.   The refractory composition according to any one of claims 1 to 8, further comprising a reaction catalyst for reacting at least one of a phenol resin, tar and pitch with 2-furaldehyde.